Merge pull request #785 from khipp/update-homebrew

Update Homebrew installation instructions

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,49 @@
+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: bug
+assignees: ''
+
+---
+
+## Example bug report template
+
+> Don't worry if you have trouble getting some of this info. Just leave it out.
+
+**Description of the bug**
+> Please don't just say it's "not working".
+
+**Steps to reproduce**
+> Steps to reproduce the bug. This usually doesn't need to be super detailed.
+1. Go to '...'
+2. Click on '...'
+3. See error message '...'
+
+**Versions**
+> Please complete the following information.
+ - Background Music: [e.g. "0.4.3" or "0.4.0-SNAPSHOT-c0ab98b". `Preferences > About Background Music`]
+ - macOS: [e.g. "11.3 Beta (20E5172i)" or "Big Sur". ` > About This Mac`]
+
+**Hardware**
+> Delete this part if you think it's probably not necessary.
+ - Computer: [e.g. "MacBook Pro (13-inch, 2016, Four Thunderbolt 3 Ports)". ` > About This Mac`]
+ - Audio Device: [e.g. "Built-in Output. Manufacturer: Apple Inc. Output Channels: 2 [...]". `System Information app > Hardware > Audio`]
+
+**Debug logs**
+> If you think the developers might not be able to reproduce the bug on their computers, e.g. because an important feature is completely broken and they would have noticed, it can help to include [debug logs](https://github.com/kyleneideck/BackgroundMusic/wiki/Getting-Debug-Logs). This takes a little effort, so feel free to leave it out at first.
+
+[Debug logs attached here](https://github.com/example/background-music-debug-logs.txt)
+
+**Other info**
+> Anything else you want to add?
+
+---
+
+> Tips
+> (Delete this section before posting.)
+>  - https://github.com/kyleneideck/BackgroundMusic#troubleshooting
+>  - Try the latest SNAPSHOT version from https://github.com/kyleneideck/BackgroundMusic/releases (if it's newer than the latest non-SNAPSHOT release).
+>  - If your bug is one of these common issues, consider leaving a comment or a +1 (👍) on an existing issue:
+>     - Background Music currently only supports audio devices with two channels. Bluetooth devices often only have one.
+>     - Volumes having no effect for certain apps: Microsoft Teams ([workaround](https://github.com/kyleneideck/BackgroundMusic/issues/268#issuecomment-604977210)), Zoom ([workaround](https://github.com/kyleneideck/BackgroundMusic/issues/396#issuecomment-741992157)), Discord ([workaround](https://github.com/kyleneideck/BackgroundMusic/issues/210#issuecomment-507048957), [see also](https://github.com/kyleneideck/BackgroundMusic/issues/267#issuecomment-617327850)), Chrome (sometimes)

.github/ISSUE_TEMPLATE/other.md

@@ -0,0 +1,10 @@
+---
+name: Other
+about: Feature request, question, support request or anything else
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+> There's no template for this issue type. I just wanted to make it clear that it's OK to submit other types of issues.

.github/workflows/build-test-release.yml

@@ -0,0 +1,216 @@
+# TODO: Split this into multiple .yml files? Multiple jobs?
+name: Build, Test and Release
+
+on:
+  push:
+    branches:
+      - '*'
+    tags:
+      - '*'
+  pull_request:
+    branches:
+      - '*'
+
+jobs:
+  # Build and test in the same job because the UI tests expect BGMDriver to be installed.
+  build-and-test:
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 30
+    strategy:
+      matrix:
+        # TODO: Add older macOS versions.
+        os:
+          - macos-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+      - name: Work in a case-sensitive disk image.
+        # This lets us catch failures that only happen on case-sensitive filesystems.
+        run: |
+          hdiutil create \
+            -type SPARSEBUNDLE \
+            -fs 'Case-sensitive Journaled HFS+' \
+            -volname bgmbuild \
+            -nospotlight \
+            -verbose \
+            -attach \
+            -size 100m \
+            bgmbuild.dmg
+          sudo cp -r . /Volumes/bgmbuild
+          cd /Volumes/bgmbuild
+      - name: Install coreutils for actions/runner/issues/884 workaround.
+        # See https://github.com/actions/runner/issues/884#issuecomment-1018851327
+        run: brew install coreutils
+      - name: Build and install Background Music.
+        run: |
+          # `sudo` and `tput` expect this to be set.
+          export TERM=xterm-256color
+          genv --default-signal=PIPE yes | sudo ./build_and_install.sh
+      - name: Print the log file.
+        if: always()
+        run: cat build_and_install.log
+      - name: Log some checksums.
+        run: 'find */build/Release/*/ -type f -exec md5 {} \;'
+      - name: Log the installed audio devices and their IDs.
+        run: |
+          system_profiler SPAudioDataType
+          say -a '?'
+      - name: Check the BGM dirs and files were installed.
+        run: |
+          # These commands fail if the dir/file isn't found.
+          ls -la "/Applications/Background Music.app"
+          ls -la "/Library/Audio/Plug-Ins/HAL/Background Music Device.driver"
+          ls -la "/usr/local/libexec/BGMXPCHelper.xpc" \
+            || ls -la "/Library/Application Support/Background Music/BGMXPCHelper.xpc"
+          ls -la "/Library/LaunchDaemons/com.bearisdriving.BGM.XPCHelper.plist"
+      - name: Close BGMApp (which the install script opened).
+        run: >-
+          osascript -e 'tell application "Background Music" to quit'
+          || killall "Background Music"
+      - name: Skip the UI tests. (They don't work on GitHub Actions yet.)
+        run: BGMApp/BGMAppTests/UITests/skip-ui-tests.py
+      - name: Run the tests.
+        run: |
+          echo '::group::BGMDriver Tests'
+          xcodebuild \
+            -quiet \
+            -workspace BGM.xcworkspace \
+            -scheme 'Background Music Device' \
+            test
+          echo '::endgroup::'
+
+          echo '::group::BGMXPCHelper Tests'
+          xcodebuild \
+            -quiet \
+            -workspace BGM.xcworkspace \
+            -scheme 'BGMXPCHelper' \
+            test
+          echo '::endgroup::'
+
+          # Grant BGMApp authorization to use input devices.
+          # This is necessary for the UI tests because accepting the "Background Music would like to
+          # use the microphone" dialog programmatically isn't reliable.
+          # TODO: Commented out because we would need to generate the csreq (codesign signature)
+          #       value to match the BGMApp bundle the tests will run against.
+          # dbPath="$HOME/Library/Application Support/com.apple.TCC/TCC.db"
+          # values="'kTCCServiceMicrophone','com.bearisdriving.BGM.App',0,2,2,1,X'FADE0C000000004800000001000000070000000800000014545ABE68FAF437700B14984BB24117EDDA1BBF2C0000000800000014386FB63B9CD6BA6E83CEDEAF4EDEE177C1FAEA92',NULL,NULL,'UNUSED',NULL,0,1652845317"
+          # sqlQuery="INSERT OR IGNORE INTO access VALUES($values);"
+          # sqlite3 "$dbPath" "$sqlQuery" || (echo "Failed to modify $dbPath"; exit 1)
+          # # Log the added TCC.db entry.
+          # sqlite3 "$dbPath" "select * from access where client like '%BGM%';"
+
+          echo '::group::BGMApp Tests'
+          # TODO: Commented out in case it uses too much CPU.
+          # log stream --info \
+          #   --predicate 'process == "coreaudiod" or
+          #                process == "Background Music" or
+          #                process == "BGMXPCHelper" or
+          #                composedMessage contains[cd] "Background Music" or
+          #                composedMessage contains "BGM"' > app.log &
+          xcodebuild \
+            -quiet \
+            -workspace BGM.xcworkspace \
+            -scheme 'Background Music' \
+            test
+          echo '::endgroup::'
+      - name: Upload the test results.
+        if: always()
+        uses: actions/upload-artifact@v3
+        with:
+          name: bgm-test-results
+          path: |
+            /Users/runner/Library/Developer/Xcode/DerivedData/*/Logs/Test/*.xcresult
+            app.log
+            /Users/runner/Library/Logs/CrashReporter/*
+            /Users/runner/Library/Logs/DiagnosticReports/*
+      - name: Uninstall Background Music.
+        run: |
+          # `tput` expects this to be set.
+          export TERM=xterm-256color
+          genv --default-signal=PIPE yes | sudo ./uninstall.sh
+      - name: Check the BGM dirs and files were removed.
+        run: |
+          if ls -la "/Applications/Background Music.app"; then exit 1; fi
+          if ls -la "/Library/Audio/Plug-Ins/HAL/Background Music Device.driver"; then exit 1; fi
+          if ls -la "/usr/local/libexec/BGMXPCHelper.xpc"; then exit 1; fi
+          if ls -la "/Library/Application Support/Background Music/BGMXPCHelper.xpc"; then
+            exit 1
+          fi
+          if ls -la "/Library/LaunchDaemons/com.bearisdriving.BGM.XPCHelper.plist"; then exit 1; fi
+  release:
+    runs-on: macos-latest
+    timeout-minutes: 15
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+      - name: Build the .pkg installer.
+        run: |
+          # `sudo` and `tput` expect this to be set.
+          export TERM=xterm-256color
+          # If this build is for a tag with "DEBUG" in its name, build a debug package. (More
+          # detailed logging, no optimization, etc.)
+          if [[ "$GITHUB_REF" =~ .*DEBUG.* ]]; then
+            sudo ./package.sh -d
+          else
+            sudo ./package.sh
+          fi
+      - name: Install the .pkg.
+        # Delete archives/ first because it contains a copy of Background Music.app.
+        # Background Music.app is "relocatable", which means that if the user moves it and then
+        # installs a new version, macOS will put the new version in the same place. This makes sure
+        # the installer puts Background Music.app in /Applications so the build won't fail when we
+        # check that later.
+        #
+        # package.sh puts the archives in a zipfile next to the .pkg, so we can still upload them
+        # after deleting the directory here.
+        #
+        # TODO: On TravisCI, this was failing for debug builds. We couldn't figure out why, so we
+        #       might have to ignore that with
+        #       || [[ "$GITHUB_REF" =~ .*DEBUG.* ]]
+        run: |
+          sudo rm -rf archives
+          sudo installer \
+            -pkg Background-Music-*/BackgroundMusic-*.pkg \
+            -target / \
+            -verbose \
+            -dumplog
+      - name: Print the installer logs.
+        if: always()
+        # This trims the start of the log to save space.
+        run: grep -E -A 9999 -B 20 'Background.?Music' /var/log/install.log
+      - name: Check the BGM dirs and files were installed.
+        if: always()
+        run: |
+          ls -la "/Applications/Background Music.app"
+          ls -la "/Library/Audio/Plug-Ins/HAL/Background Music Device.driver"
+          ls -la "/usr/local/libexec/BGMXPCHelper.xpc" \
+            || ls -la "/Library/Application Support/Background Music/BGMXPCHelper.xpc"
+          ls -la "/Library/LaunchDaemons/com.bearisdriving.BGM.XPCHelper.plist"
+      - name: Upload the .pkg installer and archives.
+        if: always()
+        uses: actions/upload-artifact@v3
+        with:
+          name: pkg-installer
+          path: Background-Music-*
+      - name: Upload the log file from the package.sh build.
+        if: always()
+        uses: actions/upload-artifact@v3
+        with:
+          name: build-and-install-log-for-pkg
+          path: build_and_install.log
+# TODO: Create a GitHub release. This is the Travis YAML that was handling it:
+# deploy:
+#  provider: releases
+#  api_key:
+#    secure: j5Gd[...]
+#  file_glob: true
+#  file: Background-Music-*/*
+#  skip_cleanup: true
+#  name: $TRAVIS_TAG
+#  prerelease: true
+#  draft: true
+#  on:
+#    repo: kyleneideck/BackgroundMusic
+#    tags: true
+#    # TODO: Use "condition" to build master and tags?
+#    condition: $DEPLOY = true

.gitignore

@@ -9,6 +9,7 @@ cmake-build-debug/
 BGM.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist
 Images/*.aux
 Images/*.log
+/archives/
 
 # Everything below is from https://github.com/github/gitignore/blob/master/Objective-C.gitignore
 

.travis.yml

@@ -1,124 +0,0 @@
-language: objective-c
-matrix:
-  include:
-    - os: osx
-      osx_image: xcode11
-      xcode_sdk: macosx10.14
-      sudo: required
-      env: DEPLOY=true
-    - os: osx
-      osx_image: xcode10.1
-      xcode_sdk: macosx10.14
-      sudo: required
-    - os: osx
-      osx_image: xcode10
-      xcode_sdk: macosx10.14
-      sudo: required
-    - os: osx
-      osx_image: xcode9.4
-      xcode_sdk: macosx10.13
-      sudo: required
-    - os: osx
-      osx_image: xcode9.3
-      xcode_sdk: macosx10.13
-      sudo: required
-    - os: osx
-      osx_image: xcode9.2
-      xcode_sdk: macosx10.13
-      sudo: required
-      # Fails to compile in 8.3, but it isn't clear from the logs why it fails.
-      # - os: osx
-      #   osx_image: xcode8.3
-      #   xcode_sdk: macosx10.12
-      #   sudo: required
-    - os: osx
-      osx_image: xcode7.3
-      xcode_sdk: macosx10.11
-      sudo: required
-      env: PACKAGE=false
-# branches:
-#   only:
-#     - master
-install:
-# Install Apple's NullAudio device. Travis' VMs don't have any audio devices installed.
-  - sudo xcodebuild -project BGMApp/BGMAppTests/NullAudio/AudioDriverExamples.xcodeproj -target NullAudio DSTROOT="/" install
-  - sudo launchctl kickstart -kp system/com.apple.audio.coreaudiod || sudo killall coreaudiod
-script:
-# Build in a case-sensitive disk image to catch failures that only happen on case-sensitive filesystems.
-  - hdiutil create -type SPARSEBUNDLE -fs 'Case-sensitive Journaled HFS+' -volname bgmbuild -nospotlight -verbose -attach -size 100m bgmbuild.dmg
-  - sudo cp -r . /Volumes/bgmbuild
-  - cd /Volumes/bgmbuild
-# Install Background Music.
-  - yes | ./build_and_install.sh
-# Print the log file, but put it in a fold because it's so long.
-  - echo -en 'build_and_install.log\ntravis_fold:start:build.log\\r'
-  - cat build_and_install.log
-  - echo -en 'travis_fold:end:build.log\\r'
-  - find */build/Release/*/ -type f -exec md5 {} \;
-# Log the installed audio devices...
-  - system_profiler SPAudioDataType
-# ...and their IDs.
-  - say -a '?'
-# Check the BGM dirs and files were installed. (These fail if the dir/file isn't found.)
-  - ls -la "/Applications/Background Music.app"
-  - ls -la "/Library/Audio/Plug-Ins/HAL/Background Music Device.driver"
-  - ls -la "/usr/local/libexec/BGMXPCHelper.xpc" || ls -la "/Library/Application Support/Background Music/BGMXPCHelper.xpc"
-  - ls -la "/Library/LaunchDaemons/com.bearisdriving.BGM.XPCHelper.plist"
-# Close BGMApp (which the install script opened).
-#
-# The killall fallback command is necessary because the AppleScript gets "user canceled" on Travis'
-# Xcode 9 images for some reason.
-  - osascript -e 'tell application "Background Music" to quit' || killall "Background Music"
-# Skip the UI tests until Travis has support for them.
-  - BGMApp/BGMAppTests/UITests/travis-skip.py
-# Run the tests.
-# The echo commands put the output into a fold in the Travis logs.
-  - echo -en 'Unit Tests\ntravis_fold:start:tests\\r'
-  - xcodebuild -workspace BGM.xcworkspace -scheme 'Background Music Device' test
-  - xcodebuild -workspace BGM.xcworkspace -scheme 'Background Music' test
-  - xcodebuild -workspace BGM.xcworkspace -scheme 'BGMXPCHelper' test
-  - echo -en 'travis_fold:end:tests\\r'
-# Uninstall Background Music.
-  - yes | ./uninstall.sh
-# Check the BGM dirs and files were removed.
-  - if ls -la "/Applications/Background Music.app"; then false; fi
-  - if ls -la "/Library/Audio/Plug-Ins/HAL/Background Music Device.driver"; then false; fi
-  - if ls -la "/usr/local/libexec/BGMXPCHelper.xpc"; then false; fi
-  - if ls -la "/Library/Application Support/Background Music/BGMXPCHelper.xpc"; then false; fi
-  - if ls -la "/Library/LaunchDaemons/com.bearisdriving.BGM.XPCHelper.plist"; then false; fi
-# Return early if we're not testing packaging on this OS X version.
-  - if [[ "$PACKAGE" == "false" ]]; then exit 0; fi
-# Build the .pkg installer. Print the build logs if it fails. If this build is for a tag with
-# "DEBUG" in its name, build a debug package. (More detailed logging, no optimization, etc.)
-  - if [[ "$TRAVIS_TAG" =~ .*DEBUG.* ]]; then
-        ./package.sh -d || (cat build_and_install.log && travis_terminate 1);
-    else
-        ./package.sh || (cat build_and_install.log && travis_terminate 1);
-    fi
-# Install the .pkg.
-  - sudo installer -pkg Background-Music-*/BackgroundMusic-*.pkg -target / -verbose -dumplog
-# Check the BGM dirs and files were installed again.
-  - ls -la "/Applications/Background Music.app"
-  - ls -la "/Library/Audio/Plug-Ins/HAL/Background Music Device.driver"
-  - ls -la "/usr/local/libexec/BGMXPCHelper.xpc" || ls -la "/Library/Application Support/Background Music/BGMXPCHelper.xpc"
-  - ls -la "/Library/LaunchDaemons/com.bearisdriving.BGM.XPCHelper.plist"
-# Post on IRC when Travis builds finish.
-notifications:
-  irc: "irc.freenode.org#backgroundmusic"
-# Upload the .pkg and dSYM zip to GitHub.
-deploy:
-  provider: releases
-  api_key:
-    secure: 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
-  file_glob: true
-  file: Background-Music-*/*
-  skip_cleanup: true
-  name: $TRAVIS_TAG
-  prerelease: true
-  on:
-    repo: kyleneideck/BackgroundMusic
-    tags: true
-    # TODO: Use "condition" to build master and tags?
-    condition: $DEPLOY = true
-
-

BGMApp/BGMApp.xcodeproj/project.pbxproj

@@ -8,12 +8,21 @@
 
 /* Begin PBXBuildFile section */
 		19FE7071FF5280BC38F35E1D /* BGMVolumeChangeListener.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 19FE7179EBFA116F3861E79D /* BGMVolumeChangeListener.cpp */; };
+		19FE70F73D26D54450779A22 /* BGMPlayThroughRTLogger.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 19FE7DE5E3BA0046ED2BC3C6 /* BGMPlayThroughRTLogger.cpp */; settings = {COMPILER_FLAGS = "-frandom-seed=BGMApp-BGMPlayThroughRTLogger.cpp"; }; };
+		19FE715E7338035C7BCD24E7 /* BGMPlayThroughRTLogger.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 19FE7DE5E3BA0046ED2BC3C6 /* BGMPlayThroughRTLogger.cpp */; };
 		19FE719951725A698A419CBA /* BGMVolumeChangeListener.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 19FE7179EBFA116F3861E79D /* BGMVolumeChangeListener.cpp */; settings = {COMPILER_FLAGS = "-frandom-seed=BGMApp-BGMVolumeChangeListener.cpp"; }; };
-		19FE72566BCEB11BD1F3D487 /* BGMMusic.m in Sources */ = {isa = PBXBuildFile; fileRef = 19FE73822ADD50BA9120AB05 /* BGMMusic.m */; };
+		19FE72566BCEB11BD1F3D487 /* BGMMusic.m in Sources */ = {isa = PBXBuildFile; fileRef = 19FE73822ADD50BA9120AB05 /* BGMMusic.m */; settings = {COMPILER_FLAGS = "-frandom-seed=BGMApp-BGMMusic.m"; }; };
+		19FE72D66CBC5C39F86333DE /* BGMPlayThroughRTLogger.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 19FE7DE5E3BA0046ED2BC3C6 /* BGMPlayThroughRTLogger.cpp */; };
+		19FE734C861E0370C21E4E94 /* BGMDebugLogging.c in Sources */ = {isa = PBXBuildFile; fileRef = 19FE73389459BF65748F531F /* BGMDebugLogging.c */; };
+		19FE7590D7565E7677D84C55 /* BGMDebugLogging.c in Sources */ = {isa = PBXBuildFile; fileRef = 19FE73389459BF65748F531F /* BGMDebugLogging.c */; };
 		19FE76F614F260F3F65AF550 /* BGMMusic.m in Sources */ = {isa = PBXBuildFile; fileRef = 19FE73822ADD50BA9120AB05 /* BGMMusic.m */; };
 		19FE77608F6C80D0B1F595A7 /* BGMStatusBarItem.mm in Sources */ = {isa = PBXBuildFile; fileRef = 19FE774DD758EC163EF4F28C /* BGMStatusBarItem.mm */; };
+		19FE78EEC6D3C3B19D1FBD64 /* BGMDebugLogging.c in Sources */ = {isa = PBXBuildFile; fileRef = 19FE73389459BF65748F531F /* BGMDebugLogging.c */; };
 		19FE7921FD1B6C037429ECA4 /* BGMStatusBarItem.mm in Sources */ = {isa = PBXBuildFile; fileRef = 19FE774DD758EC163EF4F28C /* BGMStatusBarItem.mm */; };
 		19FE7B32E1214BA0E8166A9E /* BGMMusic.m in Sources */ = {isa = PBXBuildFile; fileRef = 19FE73822ADD50BA9120AB05 /* BGMMusic.m */; };
+		19FE7B7BDF0C683288654F90 /* BGMDebugLogging.c in Sources */ = {isa = PBXBuildFile; fileRef = 19FE73389459BF65748F531F /* BGMDebugLogging.c */; settings = {COMPILER_FLAGS = "-frandom-seed=BGMApp-BGMDebugLogging.c"; }; };
+		19FE7BD48C0CA2CAF16C9ACE /* BGMPlayThroughTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 19FE761D0371DEF9FDF053D6 /* BGMPlayThroughTests.mm */; };
+		19FE7C144C12607D947EB030 /* BGMDebugLogging.c in Sources */ = {isa = PBXBuildFile; fileRef = 19FE73389459BF65748F531F /* BGMDebugLogging.c */; };
 		19FE7DFF63F69E77C53BF95E /* BGMVolumeChangeListener.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 19FE7179EBFA116F3861E79D /* BGMVolumeChangeListener.cpp */; };
 		19FE7F77376562C179449013 /* BGMStatusBarItem.mm in Sources */ = {isa = PBXBuildFile; fileRef = 19FE774DD758EC163EF4F28C /* BGMStatusBarItem.mm */; settings = {COMPILER_FLAGS = "-frandom-seed=BGMApp-BGMStatusBarItem.mm"; }; };
 		1C0BD0A51BF1A8E6004F4CF5 /* BGMAutoPauseMusicPrefs.mm in Sources */ = {isa = PBXBuildFile; fileRef = 1C0BD0A41BF1A8E6004F4CF5 /* BGMAutoPauseMusicPrefs.mm */; settings = {COMPILER_FLAGS = "-frandom-seed=BGMApp-BGMAutoPauseMusicPrefs.mm"; }; };
@@ -56,6 +65,15 @@
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+		1CE03A58239B56740036908D /* BGMDebugLoggingMenuItem.m in Sources */ = {isa = PBXBuildFile; fileRef = 1CE03A56239B56740036908D /* BGMDebugLoggingMenuItem.m */; };
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+		9E129A402602AE620005851B /* BGMASApplication.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; name = BGMASApplication.m; path = Scripting/BGMASApplication.m; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -414,6 +456,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				1C62FE5523D423D700B9B68E /* XCTest.framework in Frameworks */,
 				1C8B0C6B21645355008C5679 /* AVFoundation.framework in Frameworks */,
 				1CD989401ECFFCC50014BBBF /* AudioToolbox.framework in Frameworks */,
 			);
@@ -448,6 +491,15 @@
 /* End PBXFrameworksBuildPhase section */
 
 /* Begin PBXGroup section */
+		1C09150623F010FB001EB0E1 /* Scripts */ = {
+			isa = PBXGroup;
+			children = (
+				1C09150723F010FB001EB0E1 /* set-version.sh */,
+			);
+			name = Scripts;
+			path = ../SharedSource/Scripts;
+			sourceTree = "<group>";
+		};
 		1C0BD0A21BF1A827004F4CF5 /* Preferences Menu */ = {
 			isa = PBXGroup;
 			children = (
@@ -499,6 +551,9 @@
 				1C8034C31BDAFD5700668E00 /* CAPThread.h */,
 				1C1962E21BC94E15008A4DF7 /* CARingBuffer.cpp */,
 				1C1962E31BC94E15008A4DF7 /* CARingBuffer.h */,
+				19FE7908A33FA7BD97B432D9 /* BGMDebugLogging.h */,
+				19FE73389459BF65748F531F /* BGMDebugLogging.c */,
+				19FE71BCD79E7246F7345C16 /* BGMThreadSafetyAnalysis.h */,
 			);
 			name = PublicUtility;
 			sourceTree = "<group>";
@@ -511,6 +566,8 @@
 				1C2FC31D1EC723A100A76592 /* BGMASOutputDevice.h */,
 				1C2FC31A1EC7238A00A76592 /* BGMASOutputDevice.mm */,
 				1C2FC2FF1EB4D6E700A76592 /* BGMApp.sdef */,
+				9E129A3F2602AE620005851B /* BGMASApplication.h */,
+				9E129A402602AE620005851B /* BGMASApplication.m */,
 			);
 			name = Scripting;
 			sourceTree = "<group>";
@@ -519,6 +576,7 @@
 			isa = PBXGroup;
 			children = (
 				27D643B41C9FABBD00737F6E /* BGM_Types.h */,
+				1C09150623F010FB001EB0E1 /* Scripts */,
 				2771700F1CA0C83B00AB34B4 /* BGM_Utils.h */,
 				27FB8C2E1DE468320084DB9D /* BGM_Utils.cpp */,
 				27D643C41C9FBE5600737F6E /* BGM_TestUtils.h */,
@@ -561,10 +619,25 @@
 			name = "Music Players";
 			sourceTree = "<group>";
 		};
+		1C62FE4423D3EAC500B9B68E /* Mocks */ = {
+			isa = PBXGroup;
+			children = (
+				1C62FE4823D3EB2D00B9B68E /* Mock_CAHALAudioSystemObject.cpp */,
+				1C62FE4623D3EB2D00B9B68E /* Mock_CAHALAudioObject.cpp */,
+				1C62FE4A23D3EB2E00B9B68E /* Mock_CAHALAudioDevice.cpp */,
+				1C62FE4D23D3EB2E00B9B68E /* MockAudioObjects.h */,
+				1C62FE4723D3EB2D00B9B68E /* MockAudioObjects.cpp */,
+				1C62FE4C23D3EB2E00B9B68E /* MockAudioObject.h */,
+				1C62FE4523D3EB2D00B9B68E /* MockAudioObject.cpp */,
+				1C62FE4923D3EB2E00B9B68E /* MockAudioDevice.h */,
+				1C62FE4B23D3EB2E00B9B68E /* MockAudioDevice.cpp */,
+			);
+			path = Mocks;
+			sourceTree = "<group>";
+		};
 		1CB8B32D1BBA75EF000E2DD1 = {
 			isa = PBXGroup;
 			children = (
-				1C43DABE22F582780004AF35 /* Background Music.entitlements */,
 				1CB8B3381BBA75EF000E2DD1 /* BGMApp */,
 				1CB8B34C1BBA75F0000E2DD1 /* BGMApp Tests */,
 				27379B901C7F57DB0084A24C /* BGMXPCHelper */,
@@ -598,6 +671,8 @@
 				1C80DED220A6718600045BBE /* BGMAppWatcher.m */,
 				1C837DD61F6AA1F2004B1E60 /* BGMOutputVolumeMenuItem.h */,
 				1C837DD71F6AA1F2004B1E60 /* BGMOutputVolumeMenuItem.mm */,
+				1CE03A55239B56740036908D /* BGMDebugLoggingMenuItem.h */,
+				1CE03A56239B56740036908D /* BGMDebugLoggingMenuItem.m */,
 				1C780FF01FEF6C3B00497FAD /* BGMSystemSoundsVolume.h */,
 				1C780FF11FEF6C3B00497FAD /* BGMSystemSoundsVolume.mm */,
 				1C3DB48A1BE0888500EC8160 /* BGMAppVolumes.h */,
@@ -626,6 +701,8 @@
 				1C3D36701ED90E8600F98E66 /* BGMDeviceControlsList.cpp */,
 				1C1962E61BC94E91008A4DF7 /* BGMPlayThrough.h */,
 				1C1962E51BC94E91008A4DF7 /* BGMPlayThrough.cpp */,
+				19FE72A176FD500FB4C1F5C6 /* BGMPlayThroughRTLogger.h */,
+				19FE7DE5E3BA0046ED2BC3C6 /* BGMPlayThroughRTLogger.cpp */,
 				19FE799A86A285DD9423D164 /* BGMStatusBarItem.h */,
 				19FE774DD758EC163EF4F28C /* BGMStatusBarItem.mm */,
 				1CC6593B1F91DEB400B0CCDC /* BGMTermination.h */,
@@ -646,6 +723,8 @@
 		1CB8B3391BBA75EF000E2DD1 /* Supporting Files */ = {
 			isa = PBXGroup;
 			children = (
+				1C43DABE22F582780004AF35 /* BGMApp.entitlements */,
+				1C62FE5923D44FC000B9B68E /* BGMApp-Debug.entitlements */,
 				275343BF1DFD01BC00DF3858 /* SystemPreferences.h */,
 				1CED61681C3081C2002CAFCF /* LICENSE */,
 				1CC1DF951BE8607700FB8FE4 /* Images.xcassets */,
@@ -691,6 +770,7 @@
 			children = (
 				1CCC4F5F1E5840EF008053E4 /* BGMAppUITests-Info.plist */,
 				1CCC4F491E581C0D008053E4 /* BGMAppUnitTests-Info.plist */,
+				1C62FE5623D4278300B9B68E /* skip-ui-tests.py */,
 			);
 			name = "Supporting Files";
 			sourceTree = "<group>";
@@ -699,8 +779,9 @@
 			isa = PBXGroup;
 			children = (
 				1CCC4F4B1E581C40008053E4 /* BGMMusicPlayersUnitTests.mm */,
-				1CCC4F4C1E581C40008053E4 /* Mock_CAHALAudioObject.cpp */,
-				1CEACF4E1F34A30000FEC143 /* Mock_CAHALAudioSystemObject.cpp */,
+				19FE761D0371DEF9FDF053D6 /* BGMPlayThroughTests.mm */,
+				1C687A6A23B889E000834B75 /* BGMPlayThroughRTLoggerTests.mm */,
+				1C62FE4423D3EAC500B9B68E /* Mocks */,
 			);
 			name = "Unit Tests";
 			sourceTree = "<group>";
@@ -756,6 +837,7 @@
 		2743CA1B1D86DA9B0089613B /* Frameworks */ = {
 			isa = PBXGroup;
 			children = (
+				1C62FE5423D423D700B9B68E /* XCTest.framework */,
 				1C8034D420B0347A004BC50C /* Security.framework */,
 				1C8B0C69216205BF008C5679 /* AVFoundation.framework */,
 				270A84501E0044EE00F13C99 /* ScriptingBridge.framework */,
@@ -788,7 +870,7 @@
 				1CB8B3321BBA75EF000E2DD1 /* Sources */,
 				1CB8B3331BBA75EF000E2DD1 /* Frameworks */,
 				1CB8B3341BBA75EF000E2DD1 /* Resources */,
-				1CD440581E593DDD0064E0BC /* ShellScript */,
+				1CD440581E593DDD0064E0BC /* Run Script - set-version.sh */,
 			);
 			buildRules = (
 			);
@@ -824,7 +906,8 @@
 				27379B8B1C7F57DA0084A24C /* Sources */,
 				27379B8C1C7F57DA0084A24C /* Frameworks */,
 				27379B8D1C7F57DA0084A24C /* Resources */,
-				276972891CAFCE91007A2F7C /* ShellScript */,
+				1C09150923F0208F001EB0E1 /* Run Script - set-version.sh */,
+				276972891CAFCE91007A2F7C /* Run Script - post_install.sh */,
 			);
 			buildRules = (
 			);
@@ -902,16 +985,15 @@
 					};
 					2743C9F51D86CFF90089613B = {
 						CreatedOnToolsVersion = 8.0;
-						ProvisioningStyle = Automatic;
+						ProvisioningStyle = Manual;
 					};
 				};
 			};
 			buildConfigurationList = 1CB8B3311BBA75EF000E2DD1 /* Build configuration list for PBXProject "BGMApp" */;
 			compatibilityVersion = "Xcode 6.3";
-			developmentRegion = English;
+			developmentRegion = en;
 			hasScannedForEncodings = 0;
 			knownRegions = (
-				English,
 				en,
 				Base,
 			);
@@ -948,6 +1030,7 @@
 			isa = PBXResourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				1C62FE5823D4278300B9B68E /* skip-ui-tests.py in Resources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -978,26 +1061,46 @@
 /* End PBXResourcesBuildPhase section */
 
 /* Begin PBXShellScriptBuildPhase section */
-		1CD440581E593DDD0064E0BC /* ShellScript */ = {
+		1C09150923F0208F001EB0E1 /* Run Script - set-version.sh */ = {
+			isa = PBXShellScriptBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			inputFileListPaths = (
+			);
+			inputPaths = (
+			);
+			name = "Run Script - set-version.sh";
+			outputFileListPaths = (
+			);
+			outputPaths = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+			shellPath = /bin/sh;
+			shellScript = "# Append the git HEAD short ID to the build version for SNAPSHOT and DEBUG builds.\n\"$SRCROOT/../SharedSource/Scripts/set-version.sh\"\n";
+		};
+		1CD440581E593DDD0064E0BC /* Run Script - set-version.sh */ = {
 			isa = PBXShellScriptBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
 			);
 			inputPaths = (
 			);
+			name = "Run Script - set-version.sh";
 			outputPaths = (
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "# Append the git HEAD short ID to the build version for snapshot builds. Thanks to\n# Václav Slavík for the initial version of this: http://stackoverflow.com/a/26354117/1091063\n# TODO: Update CFBundleVersion as well?\n\n# If HEAD isn't tagged, or has \"SNAPSHOT\" or \"DEBUG\" in the tag name, this is a snapshot build.\n# If HEAD is tagged more than once, use the most recent.\nTAG=$(/usr/bin/git tag --points-at HEAD --sort='-taggerdate' 2>/dev/null | head -n 1)\nif [[ $? -eq 0 ]] && ( [[ \"${TAG}\" == \"\" ]] || \\\n        [[ \"${TAG}\" =~ .*SNAPSHOT.* ]] || \\\n        [[ \"${TAG}\" =~ .*DEBUG.* ]] ); then\n    HEAD=$(/usr/bin/git rev-list HEAD --max-count=1 --abbrev-commit)\n    INFO_PLIST=\"${BUILT_PRODUCTS_DIR}/${INFOPLIST_PATH}\"\n    if [[ \"${CONFIGURATION}\" != \"Release\" ]]; then\n        TYPE=\"DEBUG\"\n    else\n        TYPE=\"SNAPSHOT\"\n    fi\n    if [[ -f \"$INFO_PLIST\" ]]; then\n        CURRENT_VERSION=$(/usr/libexec/PlistBuddy -c \"Print :CFBundleShortVersionString\" \"${INFO_PLIST}\")\n        BASE_VERSION=$(/usr/libexec/PlistBuddy -c \"Print :BGMBundleVersionBase\" \"${INFO_PLIST}\" 2>/dev/null)\n        if [[ $? -ne 0 ]] || [[ \"${BASE_VERSION}\" == \"\" ]]; then\n            BASE_VERSION=\"${CURRENT_VERSION}\"\n            /usr/libexec/PlistBuddy -c \"Add :BGMBundleVersionBase string ${BASE_VERSION}\" \"${INFO_PLIST}\"\n        fi\n        NEW_VERSION=\"${BASE_VERSION}-${TYPE}-${HEAD}\"\n        if [[ \"${NEW_VERSION}\" != \"${CURRENT_VERSION}\" ]]; then  # Only touch the file if we need to.\n            /usr/libexec/PlistBuddy -c \"Set :CFBundleShortVersionString ${NEW_VERSION}\" \"${INFO_PLIST}\"\n        fi\n    fi\nfi\n";
+			shellScript = "# Append the git HEAD short ID to the build version for SNAPSHOT and DEBUG builds.\n\"$SRCROOT/../SharedSource/Scripts/set-version.sh\"\n";
 		};
-		276972891CAFCE91007A2F7C /* ShellScript */ = {
+		276972891CAFCE91007A2F7C /* Run Script - post_install.sh */ = {
 			isa = PBXShellScriptBuildPhase;
 			buildActionMask = 8;
 			files = (
 			);
 			inputPaths = (
 			);
+			name = "Run Script - post_install.sh";
 			outputPaths = (
 			);
 			runOnlyForDeploymentPostprocessing = 1;
@@ -1013,6 +1116,7 @@
 			files = (
 				1C86DA6A1F91EE3B000C8CCF /* CAPThread.cpp in Sources */,
 				1C780FF21FEF6C3B00497FAD /* BGMSystemSoundsVolume.mm in Sources */,
+				1CE03A57239B56740036908D /* BGMDebugLoggingMenuItem.m in Sources */,
 				1C4699471BD5C0E400F78043 /* BGMiTunes.m in Sources */,
 				1CD410D41F9EDDAD0070A094 /* BGMAppVolumesController.mm in Sources */,
 				1C1962E41BC94E15008A4DF7 /* CARingBuffer.cpp in Sources */,
@@ -1053,6 +1157,7 @@
 				1C837DD81F6AA1F2004B1E60 /* BGMOutputVolumeMenuItem.mm in Sources */,
 				1C9258472090287F00B8D3A6 /* BGMGooglePlayMusicDesktopPlayerConnection.m in Sources */,
 				1C1963011BCAC0F6008A4DF7 /* CACFString.cpp in Sources */,
+				9E129A412602AE620005851B /* BGMASApplication.m in Sources */,
 				1C1962E71BC94E91008A4DF7 /* BGMPlayThrough.cpp in Sources */,
 				1C8D8304204238DB00A838F2 /* BGMSwinsian.m in Sources */,
 				1C1962FA1BCAC061008A4DF7 /* CADebugMacros.cpp in Sources */,
@@ -1067,6 +1172,8 @@
 				19FE7F77376562C179449013 /* BGMStatusBarItem.mm in Sources */,
 				19FE719951725A698A419CBA /* BGMVolumeChangeListener.cpp in Sources */,
 				19FE72566BCEB11BD1F3D487 /* BGMMusic.m in Sources */,
+				19FE70F73D26D54450779A22 /* BGMPlayThroughRTLogger.cpp in Sources */,
+				19FE7B7BDF0C683288654F90 /* BGMDebugLogging.c in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -1076,6 +1183,7 @@
 			files = (
 				1C8104B022AD082E00B35517 /* BGMGooglePlayMusicDesktopPlayer.m in Sources */,
 				1C8D830520423E1C00A838F2 /* BGMSwinsian.m in Sources */,
+				1CE03A58239B56740036908D /* BGMDebugLoggingMenuItem.m in Sources */,
 				1CACCF3A1F334447007F86CA /* BGMBackgroundMusicDevice.cpp in Sources */,
 				1C780FF31FEF6C3B00497FAD /* BGMSystemSoundsVolume.mm in Sources */,
 				1CC6593D1F91DEB400B0CCDC /* BGMTermination.mm in Sources */,
@@ -1116,6 +1224,7 @@
 				1CD989361ECFFC9E0014BBBF /* CACFDictionary.cpp in Sources */,
 				1CD989371ECFFC9E0014BBBF /* CACFNumber.cpp in Sources */,
 				1CD989381ECFFC9E0014BBBF /* CACFString.cpp in Sources */,
+				9E542C7026057FBA0016C0B5 /* BGMASApplication.m in Sources */,
 				1CD989391ECFFC9E0014BBBF /* CADebugger.cpp in Sources */,
 				1CD9893A1ECFFC9E0014BBBF /* CADebugMacros.cpp in Sources */,
 				1CD9893B1ECFFC9E0014BBBF /* CADebugPrintf.cpp in Sources */,
@@ -1130,6 +1239,8 @@
 				19FE7921FD1B6C037429ECA4 /* BGMStatusBarItem.mm in Sources */,
 				19FE7DFF63F69E77C53BF95E /* BGMVolumeChangeListener.cpp in Sources */,
 				19FE7B32E1214BA0E8166A9E /* BGMMusic.m in Sources */,
+				19FE72D66CBC5C39F86333DE /* BGMPlayThroughRTLogger.cpp in Sources */,
+				19FE734C861E0370C21E4E94 /* BGMDebugLogging.c in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -1158,6 +1269,7 @@
 				27D643C01C9FB99200737F6E /* BGMXPCHelperService.mm in Sources */,
 				27D643C11C9FB99200737F6E /* main.m in Sources */,
 				277170161CA24D7C00AB34B4 /* BGMXPCListenerDelegate.m in Sources */,
+				19FE7590D7565E7677D84C55 /* BGMDebugLogging.c in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -1165,10 +1277,10 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				1C62FE5123D3EB2E00B9B68E /* Mock_CAHALAudioSystemObject.cpp in Sources */,
 				1C8104AF22AD07E200B35517 /* BGMAppWatcher.m in Sources */,
 				1C8D830620423E2400A838F2 /* BGMSwinsian.m in Sources */,
 				1C227C0B1FA4C48200A95B6D /* BGMAppVolumes.m in Sources */,
-				1CEACF4D1F34793700FEC143 /* CAHALAudioDevice.cpp in Sources */,
 				1CACCF3B1F334450007F86CA /* BGMBackgroundMusicDevice.cpp in Sources */,
 				1C8D830C2042DE9600A838F2 /* BGMGooglePlayMusicDesktopPlayer.m in Sources */,
 				1C3D36741ED90E8600F98E66 /* BGMDeviceControlsList.cpp in Sources */,
@@ -1176,14 +1288,16 @@
 				27FB8C311DE4758A0084DB9D /* BGM_Utils.cpp in Sources */,
 				27FB8C071DD75D0A0084DB9D /* BGMHermes.m in Sources */,
 				2743CA211D86DE780089613B /* BGMDeviceControlSync.cpp in Sources */,
+				1CE03A59239B56740036908D /* BGMDebugLoggingMenuItem.m in Sources */,
 				2743CA0C1D86D7FA0089613B /* CACFArray.cpp in Sources */,
 				1C837DDA1F6AA1F2004B1E60 /* BGMOutputVolumeMenuItem.mm in Sources */,
 				2743CA0D1D86D7FA0089613B /* CACFDictionary.cpp in Sources */,
 				2743CA0E1D86D7FA0089613B /* CACFNumber.cpp in Sources */,
 				2743CA0F1D86D7FA0089613B /* CACFString.cpp in Sources */,
-				1CCC4F4E1E581C40008053E4 /* Mock_CAHALAudioObject.cpp in Sources */,
 				2743CA101D86D7FA0089613B /* CADebugger.cpp in Sources */,
+				1C687A6B23B889E000834B75 /* BGMPlayThroughRTLoggerTests.mm in Sources */,
 				2743CA111D86D7FA0089613B /* CADebugMacros.cpp in Sources */,
+				1C62FE4F23D3EB2E00B9B68E /* Mock_CAHALAudioObject.cpp in Sources */,
 				2743CA121D86D7FA0089613B /* CADebugPrintf.cpp in Sources */,
 				1CCC4F4D1E581C40008053E4 /* BGMMusicPlayersUnitTests.mm in Sources */,
 				2743CA141D86D7FA0089613B /* CAHALAudioStream.cpp in Sources */,
@@ -1193,7 +1307,6 @@
 				2743CA191D86D7FA0089613B /* CARingBuffer.cpp in Sources */,
 				2743CA0A1D86D52D0089613B /* BGMAudioDeviceManager.mm in Sources */,
 				2743CA031D86D41C0089613B /* BGMScriptingBridge.m in Sources */,
-				1CEACF4F1F34A30000FEC143 /* Mock_CAHALAudioSystemObject.cpp in Sources */,
 				2743CA041D86D41C0089613B /* BGMMusicPlayer.m in Sources */,
 				1CD410D61F9EDDAD0070A094 /* BGMAppVolumesController.mm in Sources */,
 				2743CA051D86D41C0089613B /* BGMDecibel.m in Sources */,
@@ -1201,14 +1314,21 @@
 				2743CA071D86D41C0089613B /* BGMVLC.m in Sources */,
 				1CF5423D1EAAEE4300445AD8 /* BGMAudioDevice.cpp in Sources */,
 				2743CA081D86D41C0089613B /* BGMVOX.m in Sources */,
+				1C62FE5223D3EB2E00B9B68E /* Mock_CAHALAudioDevice.cpp in Sources */,
+				1C62FE5323D3EB2E00B9B68E /* MockAudioDevice.cpp in Sources */,
 				2743CA091D86D41C0089613B /* BGMUserDefaults.m in Sources */,
+				1C62FE5023D3EB2E00B9B68E /* MockAudioObjects.cpp in Sources */,
 				1CC6593E1F91DEB400B0CCDC /* BGMTermination.mm in Sources */,
 				2743CA011D86D3CB0089613B /* BGMMusicPlayers.mm in Sources */,
+				1C62FE4E23D3EB2E00B9B68E /* MockAudioObject.cpp in Sources */,
 				2743CA021D86D3CB0089613B /* BGMiTunes.m in Sources */,
 				19FE77608F6C80D0B1F595A7 /* BGMStatusBarItem.mm in Sources */,
 				19FE7071FF5280BC38F35E1D /* BGMVolumeChangeListener.cpp in Sources */,
 				1C9258492090287F00B8D3A6 /* BGMGooglePlayMusicDesktopPlayerConnection.m in Sources */,
 				19FE76F614F260F3F65AF550 /* BGMMusic.m in Sources */,
+				19FE715E7338035C7BCD24E7 /* BGMPlayThroughRTLogger.cpp in Sources */,
+				19FE78EEC6D3C3B19D1FBD64 /* BGMDebugLogging.c in Sources */,
+				19FE7BD48C0CA2CAF16C9ACE /* BGMPlayThroughTests.mm in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -1217,6 +1337,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				1CCC4F3E1E58196C008053E4 /* BGMXPCHelperTests.m in Sources */,
+				19FE7C144C12607D947EB030 /* BGMDebugLogging.c in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -1278,6 +1399,7 @@
 				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = NO;
 				CLANG_WARN_OBJC_REPEATED_USE_OF_WEAK = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_QUOTED_INCLUDE_IN_FRAMEWORK_HEADER = YES;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
 				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_IMPLICIT_CONVERSION = YES;
@@ -1321,7 +1443,7 @@
 				GCC_WARN_UNUSED_LABEL = YES;
 				GCC_WARN_UNUSED_PARAMETER = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				MACOSX_DEPLOYMENT_TARGET = 10.9;
+				MACOSX_DEPLOYMENT_TARGET = 10.13;
 				MTL_ENABLE_DEBUG_INFO = YES;
 				ONLY_ACTIVE_ARCH = YES;
 				OTHER_CFLAGS = "-fno-omit-frame-pointer";
@@ -1336,20 +1458,23 @@
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				CLANG_USE_OPTIMIZATION_PROFILE = NO;
-				CODE_SIGN_ENTITLEMENTS = "Background Music.entitlements";
+				CLANG_WARN_ATOMIC_IMPLICIT_SEQ_CST = YES;
+				CODE_SIGN_ENTITLEMENTS = "BGMApp/BGMApp-Debug.entitlements";
 				COMBINE_HIDPI_IMAGES = YES;
 				DEAD_CODE_STRIPPING = YES;
 				DEPLOYMENT_POSTPROCESSING = NO;
 				DWARF_DSYM_FILE_NAME = "$(EXECUTABLE_NAME).dSYM";
 				DWARF_DSYM_FOLDER_PATH = "$(CONFIGURATION_BUILD_DIR)/$(EXECUTABLE_FOLDER_PATH)";
-				ENABLE_HARDENED_RUNTIME = YES;
 				GCC_TREAT_WARNINGS_AS_ERRORS = YES;
 				INFOPLIST_FILE = BGMApp/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = com.bearisdriving.BGM.App;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				STRIP_STYLE = "non-global";
-				WARNING_CFLAGS = "-Wpartial-availability";
+				WARNING_CFLAGS = (
+					"-Wpartial-availability",
+					"-Wthread-safety",
+				);
 			};
 			name = DebugOpt;
 		};
@@ -1384,6 +1509,7 @@
 				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = NO;
 				CLANG_WARN_OBJC_REPEATED_USE_OF_WEAK = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_QUOTED_INCLUDE_IN_FRAMEWORK_HEADER = YES;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
 				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_IMPLICIT_CONVERSION = YES;
@@ -1427,7 +1553,7 @@
 				GCC_WARN_UNUSED_LABEL = YES;
 				GCC_WARN_UNUSED_PARAMETER = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				MACOSX_DEPLOYMENT_TARGET = 10.9;
+				MACOSX_DEPLOYMENT_TARGET = 10.13;
 				MTL_ENABLE_DEBUG_INFO = YES;
 				ONLY_ACTIVE_ARCH = YES;
 				OTHER_CFLAGS = "-fno-omit-frame-pointer";
@@ -1468,6 +1594,7 @@
 				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = NO;
 				CLANG_WARN_OBJC_REPEATED_USE_OF_WEAK = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_QUOTED_INCLUDE_IN_FRAMEWORK_HEADER = YES;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
 				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_IMPLICIT_CONVERSION = YES;
@@ -1508,7 +1635,7 @@
 				GCC_WARN_UNUSED_LABEL = YES;
 				GCC_WARN_UNUSED_PARAMETER = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				MACOSX_DEPLOYMENT_TARGET = 10.9;
+				MACOSX_DEPLOYMENT_TARGET = 10.13;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				OTHER_CFLAGS = "";
 				RUN_CLANG_STATIC_ANALYZER = YES;
@@ -1522,20 +1649,23 @@
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				CLANG_USE_OPTIMIZATION_PROFILE = NO;
-				CODE_SIGN_ENTITLEMENTS = "Background Music.entitlements";
+				CLANG_WARN_ATOMIC_IMPLICIT_SEQ_CST = YES;
+				CODE_SIGN_ENTITLEMENTS = "BGMApp/BGMApp-Debug.entitlements";
 				COMBINE_HIDPI_IMAGES = YES;
 				DEAD_CODE_STRIPPING = YES;
 				DEPLOYMENT_POSTPROCESSING = NO;
 				DWARF_DSYM_FILE_NAME = "$(EXECUTABLE_NAME).dSYM";
 				DWARF_DSYM_FOLDER_PATH = "$(CONFIGURATION_BUILD_DIR)/$(EXECUTABLE_FOLDER_PATH)";
-				ENABLE_HARDENED_RUNTIME = YES;
 				GCC_TREAT_WARNINGS_AS_ERRORS = YES;
 				INFOPLIST_FILE = BGMApp/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = com.bearisdriving.BGM.App;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				STRIP_STYLE = "non-global";
-				WARNING_CFLAGS = "-Wpartial-availability";
+				WARNING_CFLAGS = (
+					"-Wpartial-availability",
+					"-Wthread-safety",
+				);
 			};
 			name = Debug;
 		};
@@ -1544,13 +1674,22 @@
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				CLANG_USE_OPTIMIZATION_PROFILE = NO;
-				CODE_SIGN_ENTITLEMENTS = "Background Music.entitlements";
+				CLANG_WARN_ATOMIC_IMPLICIT_SEQ_CST = YES;
+				CODE_SIGN_ENTITLEMENTS = BGMApp/BGMApp.entitlements;
 				COMBINE_HIDPI_IMAGES = YES;
 				DEAD_CODE_STRIPPING = YES;
 				DEPLOYMENT_POSTPROCESSING = YES;
 				DWARF_DSYM_FILE_NAME = "$(EXECUTABLE_NAME).dSYM";
 				DWARF_DSYM_FOLDER_PATH = "$(CONFIGURATION_BUILD_DIR)/$(EXECUTABLE_FOLDER_PATH)";
-				ENABLE_HARDENED_RUNTIME = YES;
+				GCC_PREPROCESSOR_DEFINITIONS = (
+					"DEBUG=0",
+					"CoreAudio_Debug=0",
+					"CoreAudio_StopOnAssert=0",
+					"BGM_StopDebuggerOnLoggedExceptions=$(BGM_STOP_DEBUGGER_ON_LOGGED_EXCEPTIONS)",
+					"BGM_StopDebuggerOnLoggedUnexpectedExceptions=$(BGM_STOP_DEBUGGER_ON_LOGGED_UNEXPECTED_EXCEPTIONS)",
+					"CoreAudio_StopOnThrow=0",
+					"CoreAudio_UseSysLog=1",
+				);
 				GCC_TREAT_WARNINGS_AS_ERRORS = YES;
 				INFOPLIST_FILE = BGMApp/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks";
@@ -1561,6 +1700,7 @@
 				WARNING_CFLAGS = (
 					"-Wno-profile-instr-out-of-date",
 					"-Wpartial-availability",
+					"-Wthread-safety",
 				);
 			};
 			name = Release;
@@ -1568,14 +1708,16 @@
 		1CCC4F5C1E584081008053E4 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CODE_SIGN_ENTITLEMENTS = "BGMApp/BGMApp-Debug.entitlements";
 				COMBINE_HIDPI_IMAGES = YES;
 				COPY_PHASE_STRIP = NO;
 				DEBUG_INFORMATION_FORMAT = dwarf;
+				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = "BGMAppTests/UITests/BGMAppUITests-Info.plist";
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/../Frameworks";
-				MACOSX_DEPLOYMENT_TARGET = 10.11;
 				PRODUCT_BUNDLE_IDENTIFIER = com.bearisdriving.BGM.AppUITests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				PROVISIONING_PROFILE_SPECIFIER = "";
 				TEST_TARGET_NAME = "Background Music";
 				WARNING_CFLAGS = "";
 			};
@@ -1584,13 +1726,15 @@
 		1CCC4F5D1E584081008053E4 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CODE_SIGN_ENTITLEMENTS = "BGMApp/BGMApp-Debug.entitlements";
 				COMBINE_HIDPI_IMAGES = YES;
 				COPY_PHASE_STRIP = NO;
+				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = "BGMAppTests/UITests/BGMAppUITests-Info.plist";
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/../Frameworks";
-				MACOSX_DEPLOYMENT_TARGET = 10.11;
 				PRODUCT_BUNDLE_IDENTIFIER = com.bearisdriving.BGM.AppUITests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				PROVISIONING_PROFILE_SPECIFIER = "";
 				TEST_TARGET_NAME = "Background Music";
 				WARNING_CFLAGS = "";
 			};
@@ -1599,14 +1743,16 @@
 		1CCC4F5E1E584081008053E4 /* DebugOpt */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				CODE_SIGN_ENTITLEMENTS = "BGMApp/BGMApp-Debug.entitlements";
 				COMBINE_HIDPI_IMAGES = YES;
 				COPY_PHASE_STRIP = NO;
 				DEBUG_INFORMATION_FORMAT = dwarf;
+				DEVELOPMENT_TEAM = "";
 				INFOPLIST_FILE = "BGMAppTests/UITests/BGMAppUITests-Info.plist";
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/../Frameworks";
-				MACOSX_DEPLOYMENT_TARGET = 10.11;
 				PRODUCT_BUNDLE_IDENTIFIER = com.bearisdriving.BGM.AppUITests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				PROVISIONING_PROFILE_SPECIFIER = "";
 				TEST_TARGET_NAME = "Background Music";
 				WARNING_CFLAGS = "";
 			};
@@ -1615,6 +1761,7 @@
 		27379B991C7F57DB0084A24C /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				COPY_PHASE_STRIP = NO;
 				DEPLOYMENT_POSTPROCESSING = NO;
 				GCC_PREPROCESSOR_DEFINITIONS = (
 					"DEBUG=1",
@@ -1628,12 +1775,14 @@
 				INSTALL_PATH = /usr/local/libexec;
 				PRODUCT_BUNDLE_IDENTIFIER = com.bearisdriving.BGM.XPCHelper;
 				PRODUCT_NAME = BGMXPCHelper;
+				STRIP_INSTALLED_PRODUCT = NO;
 			};
 			name = Debug;
 		};
 		27379B9A1C7F57DB0084A24C /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				COPY_PHASE_STRIP = NO;
 				DEPLOYMENT_POSTPROCESSING = YES;
 				INFOPLIST_FILE = BGMXPCHelper/Info.plist;
 				INSTALL_GROUP = wheel;
@@ -1642,12 +1791,14 @@
 				LLVM_LTO = YES;
 				PRODUCT_BUNDLE_IDENTIFIER = com.bearisdriving.BGM.XPCHelper;
 				PRODUCT_NAME = BGMXPCHelper;
+				STRIP_INSTALLED_PRODUCT = NO;
 			};
 			name = Release;
 		};
 		27379B9B1C7F57DB0084A24C /* DebugOpt */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
+				COPY_PHASE_STRIP = NO;
 				DEPLOYMENT_POSTPROCESSING = NO;
 				GCC_PREPROCESSOR_DEFINITIONS = (
 					"DEBUG=1",
@@ -1661,6 +1812,7 @@
 				INSTALL_PATH = /usr/local/libexec;
 				PRODUCT_BUNDLE_IDENTIFIER = com.bearisdriving.BGM.XPCHelper;
 				PRODUCT_NAME = BGMXPCHelper;
+				STRIP_INSTALLED_PRODUCT = NO;
 			};
 			name = DebugOpt;
 		};
@@ -1672,11 +1824,25 @@
 				CLANG_WARN_SUSPICIOUS_MOVES = YES;
 				CLANG_WARN__EXIT_TIME_DESTRUCTORS = NO;
 				CODE_SIGN_IDENTITY = "";
+				CODE_SIGN_STYLE = Manual;
 				COMBINE_HIDPI_IMAGES = YES;
+				DEVELOPMENT_TEAM = "";
+				GCC_PREPROCESSOR_DEFINITIONS = (
+					"DEBUG=1",
+					"CoreAudio_Debug=1",
+					"CoreAudio_UseSysLog=1",
+					"CoreAudio_StopOnAssert=1",
+					"CoreAudio_ThreadStampMessages=0",
+					"BGM_StopDebuggerOnLoggedExceptions=$(BGM_STOP_DEBUGGER_ON_LOGGED_EXCEPTIONS)",
+					"BGM_StopDebuggerOnLoggedUnexpectedExceptions=$(BGM_STOP_DEBUGGER_ON_LOGGED_UNEXPECTED_EXCEPTIONS)",
+					"CoreAudio_StopOnThrow=0",
+					"BGM_UnitTest=1",
+				);
 				INFOPLIST_FILE = "BGMAppTests/UnitTests/BGMAppUnitTests-Info.plist";
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/../Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = com.bearisdriving.BGM.AppUnitTests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				PROVISIONING_PROFILE_SPECIFIER = "";
 				WARNING_CFLAGS = "";
 			};
 			name = Debug;
@@ -1689,11 +1855,23 @@
 				CLANG_WARN_SUSPICIOUS_MOVES = YES;
 				CLANG_WARN__EXIT_TIME_DESTRUCTORS = NO;
 				CODE_SIGN_IDENTITY = "";
+				CODE_SIGN_STYLE = Manual;
 				COMBINE_HIDPI_IMAGES = YES;
+				DEVELOPMENT_TEAM = "";
+				GCC_PREPROCESSOR_DEFINITIONS = (
+					"DEBUG=0",
+					"CoreAudio_Debug=0",
+					"CoreAudio_StopOnAssert=0",
+					"BGM_StopDebuggerOnLoggedExceptions=$(BGM_STOP_DEBUGGER_ON_LOGGED_EXCEPTIONS)",
+					"BGM_StopDebuggerOnLoggedUnexpectedExceptions=$(BGM_STOP_DEBUGGER_ON_LOGGED_UNEXPECTED_EXCEPTIONS)",
+					"CoreAudio_StopOnThrow=0",
+					"BGM_UnitTest=1",
+				);
 				INFOPLIST_FILE = "BGMAppTests/UnitTests/BGMAppUnitTests-Info.plist";
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/../Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = com.bearisdriving.BGM.AppUnitTests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				PROVISIONING_PROFILE_SPECIFIER = "";
 				WARNING_CFLAGS = "";
 			};
 			name = Release;
@@ -1706,11 +1884,25 @@
 				CLANG_WARN_SUSPICIOUS_MOVES = YES;
 				CLANG_WARN__EXIT_TIME_DESTRUCTORS = NO;
 				CODE_SIGN_IDENTITY = "";
+				CODE_SIGN_STYLE = Manual;
 				COMBINE_HIDPI_IMAGES = YES;
+				DEVELOPMENT_TEAM = "";
+				GCC_PREPROCESSOR_DEFINITIONS = (
+					"DEBUG=1",
+					"CoreAudio_Debug=1",
+					"CoreAudio_UseSysLog=1",
+					"CoreAudio_StopOnAssert=1",
+					"CoreAudio_ThreadStampMessages=0",
+					"BGM_StopDebuggerOnLoggedExceptions=$(BGM_STOP_DEBUGGER_ON_LOGGED_EXCEPTIONS)",
+					"BGM_StopDebuggerOnLoggedUnexpectedExceptions=$(BGM_STOP_DEBUGGER_ON_LOGGED_UNEXPECTED_EXCEPTIONS)",
+					"CoreAudio_StopOnThrow=0",
+					"BGM_UnitTest=1",
+				);
 				INFOPLIST_FILE = "BGMAppTests/UnitTests/BGMAppUnitTests-Info.plist";
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks @loader_path/../Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = com.bearisdriving.BGM.AppUnitTests;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				PROVISIONING_PROFILE_SPECIFIER = "";
 				WARNING_CFLAGS = "";
 			};
 			name = DebugOpt;

BGMApp/BGMApp.xcodeproj/xcshareddata/xcschemes/BGMXPCHelper.xcscheme

@@ -26,9 +26,42 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES"
       enableAddressSanitizer = "YES"
-      language = ""
-      shouldUseLaunchSchemeArgsEnv = "YES">
+      enableASanStackUseAfterReturn = "YES"
+      enableUBSanitizer = "YES"
+      codeCoverageEnabled = "YES"
+      onlyGenerateCoverageForSpecifiedTargets = "YES">
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "27379B8E1C7F57DA0084A24C"
+            BuildableName = "BGMXPCHelper.xpc"
+            BlueprintName = "BGMXPCHelper"
+            ReferencedContainer = "container:BGMApp.xcodeproj">
+         </BuildableReference>
+      </MacroExpansion>
+      <AdditionalOptions>
+         <AdditionalOption
+            key = "NSZombieEnabled"
+            value = "YES"
+            isEnabled = "YES">
+         </AdditionalOption>
+         <AdditionalOption
+            key = "MallocScribble"
+            value = ""
+            isEnabled = "YES">
+         </AdditionalOption>
+      </AdditionalOptions>
+      <CodeCoverageTargets>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "27379B8E1C7F57DA0084A24C"
+            BuildableName = "BGMXPCHelper.xpc"
+            BlueprintName = "BGMXPCHelper"
+            ReferencedContainer = "container:BGMApp.xcodeproj">
+         </BuildableReference>
+      </CodeCoverageTargets>
       <Testables>
          <TestableReference
             skipped = "NO">
@@ -41,24 +74,14 @@
             </BuildableReference>
          </TestableReference>
       </Testables>
-      <MacroExpansion>
-         <BuildableReference
-            BuildableIdentifier = "primary"
-            BlueprintIdentifier = "27379B8E1C7F57DA0084A24C"
-            BuildableName = "BGMXPCHelper.xpc"
-            BlueprintName = "BGMXPCHelper"
-            ReferencedContainer = "container:BGMApp.xcodeproj">
-         </BuildableReference>
-      </MacroExpansion>
-      <AdditionalOptions>
-      </AdditionalOptions>
    </TestAction>
    <LaunchAction
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       enableAddressSanitizer = "YES"
-      language = ""
+      enableASanStackUseAfterReturn = "YES"
+      enableUBSanitizer = "YES"
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
@@ -82,6 +105,16 @@
          </EnvironmentVariable>
       </EnvironmentVariables>
       <AdditionalOptions>
+         <AdditionalOption
+            key = "NSZombieEnabled"
+            value = "YES"
+            isEnabled = "YES">
+         </AdditionalOption>
+         <AdditionalOption
+            key = "MallocScribble"
+            value = ""
+            isEnabled = "YES">
+         </AdditionalOption>
       </AdditionalOptions>
    </LaunchAction>
    <ProfileAction

BGMApp/BGMApp.xcodeproj/xcshareddata/xcschemes/Background Music.xcscheme

@@ -26,11 +26,47 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES"
       enableAddressSanitizer = "YES"
-      shouldUseLaunchSchemeArgsEnv = "YES">
+      enableASanStackUseAfterReturn = "YES"
+      enableUBSanitizer = "YES"
+      codeCoverageEnabled = "YES"
+      onlyGenerateCoverageForSpecifiedTargets = "YES">
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "1CB8B3351BBA75EF000E2DD1"
+            BuildableName = "Background Music.app"
+            BlueprintName = "Background Music"
+            ReferencedContainer = "container:BGMApp.xcodeproj">
+         </BuildableReference>
+      </MacroExpansion>
+      <AdditionalOptions>
+         <AdditionalOption
+            key = "NSZombieEnabled"
+            value = "YES"
+            isEnabled = "YES">
+         </AdditionalOption>
+         <AdditionalOption
+            key = "MallocScribble"
+            value = ""
+            isEnabled = "YES">
+         </AdditionalOption>
+      </AdditionalOptions>
+      <CodeCoverageTargets>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "1CB8B3351BBA75EF000E2DD1"
+            BuildableName = "Background Music.app"
+            BlueprintName = "Background Music"
+            ReferencedContainer = "container:BGMApp.xcodeproj">
+         </BuildableReference>
+      </CodeCoverageTargets>
       <Testables>
          <TestableReference
-            skipped = "NO">
+            skipped = "NO"
+            parallelizable = "YES"
+            testExecutionOrdering = "random">
             <BuildableReference
                BuildableIdentifier = "primary"
                BlueprintIdentifier = "2743C9F51D86CFF90089613B"
@@ -50,23 +86,14 @@
             </BuildableReference>
          </TestableReference>
       </Testables>
-      <MacroExpansion>
-         <BuildableReference
-            BuildableIdentifier = "primary"
-            BlueprintIdentifier = "1CB8B3351BBA75EF000E2DD1"
-            BuildableName = "Background Music.app"
-            BlueprintName = "Background Music"
-            ReferencedContainer = "container:BGMApp.xcodeproj">
-         </BuildableReference>
-      </MacroExpansion>
-      <AdditionalOptions>
-      </AdditionalOptions>
    </TestAction>
    <LaunchAction
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       enableAddressSanitizer = "YES"
+      enableASanStackUseAfterReturn = "YES"
+      enableUBSanitizer = "YES"
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
@@ -101,6 +128,16 @@
          </EnvironmentVariable>
       </EnvironmentVariables>
       <AdditionalOptions>
+         <AdditionalOption
+            key = "NSZombieEnabled"
+            value = "YES"
+            isEnabled = "YES">
+         </AdditionalOption>
+         <AdditionalOption
+            key = "MallocScribble"
+            value = ""
+            isEnabled = "YES">
+         </AdditionalOption>
       </AdditionalOptions>
    </LaunchAction>
    <ProfileAction

BGMApp/BGMApp/BGMApp-Debug.entitlements

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>com.apple.security.automation.apple-events</key>
+	<true/>
+	<key>com.apple.security.device.audio-input</key>
+	<true/>
+    <!--
+    Without this key, AddressSanitizer and the UI tests would only work when BGMApp is code signed.
+    -->
+	<key>com.apple.security.cs.disable-library-validation</key>
+	<true/>
+</dict>
+</plist>

BGMApp/BGMApp/BGMAppDelegate.h

@@ -17,17 +17,17 @@
 //  BGMAppDelegate.h
 //  BGMApp
 //
-//  Copyright © 2016, 2017 Kyle Neideck
+//  Copyright © 2016, 2017, 2020 Kyle Neideck
+//  Copyright © 2021 Marcus Wu
 //
 //  Sets up and tears down the app.
 //
 
-// Local Includes
-#import "BGMAudioDeviceManager.h"
-
 // System Includes
 #import <Cocoa/Cocoa.h>
 
+@class BGMAudioDeviceManager;
+@class BGMAppVolumesController;
 
 // Tags for UI elements in MainMenu.xib
 static NSInteger const kVolumesHeadingMenuItemTag = 3;
@@ -50,8 +50,10 @@ static NSInteger const kSeparatorBelowVolumesMenuItemTag = 4;
 @property (unsafe_unretained) IBOutlet NSTextView* aboutPanelLicenseView;
 
 @property (weak) IBOutlet NSMenuItem* autoPauseMenuItemUnwrapped;
+@property (weak) IBOutlet NSMenuItem* debugLoggingMenuItemUnwrapped;
 
 @property (readonly) BGMAudioDeviceManager* audioDevices;
+@property BGMAppVolumesController* appVolumes;
 
 @end
 

BGMApp/BGMApp/BGMAppDelegate.mm

@@ -17,7 +17,8 @@
 //  BGMAppDelegate.mm
 //  BGMApp
 //
-//  Copyright © 2016-2019 Kyle Neideck
+//  Copyright © 2016-2022 Kyle Neideck
+//  Copyright © 2021 Marcus Wu
 //
 
 // Self Include
@@ -25,9 +26,11 @@
 
 // Local Includes
 #import "BGM_Utils.h"
+#import "BGMAppVolumes.h"
 #import "BGMAppVolumesController.h"
 #import "BGMAutoPauseMusic.h"
 #import "BGMAutoPauseMenuItem.h"
+#import "BGMDebugLoggingMenuItem.h"
 #import "BGMMusicPlayers.h"
 #import "BGMOutputDeviceMenuSection.h"
 #import "BGMOutputVolumeMenuItem.h"
@@ -63,14 +66,15 @@ static NSString* const kOptShowDockIcon      = @"--show-dock-icon";
     BGMAutoPauseMenuItem* autoPauseMenuItem;
     BGMMusicPlayers* musicPlayers;
     BGMSystemSoundsVolume* systemSoundsVolume;
-    BGMAppVolumesController* appVolumes;
     BGMOutputDeviceMenuSection* outputDeviceMenuSection;
     BGMPreferencesMenu* prefsMenu;
+    BGMDebugLoggingMenuItem* debugLoggingMenuItem;
     BGMXPCListener* xpcListener;
     BGMPreferredOutputDevices* preferredOutputDevices;
 }
 
 @synthesize audioDevices = audioDevices;
+@synthesize appVolumes = appVolumes;
 
 - (void) awakeFromNib {
     [super awakeFromNib];
@@ -115,6 +119,48 @@ static NSString* const kOptShowDockIcon      = @"--show-dock-icon";
     preferredOutputDevices =
         [[BGMPreferredOutputDevices alloc] initWithDevices:audioDevices userDefaults:userDefaults];
 
+    // Skip this if we're compiling on a version of macOS before 10.14 as won't compile and it
+    // isn't needed.
+#if MAC_OS_X_VERSION_MAX_ALLOWED >= 101400  // MAC_OS_X_VERSION_10_14
+    if (@available(macOS 10.14, *)) {
+        // On macOS 10.14+ we need to get the user's permission to use input devices before we can
+        // use BGMDevice for playthrough (see BGMPlayThrough), so we wait until they've given it
+        // before making BGMDevice the default device. This way, if the user is playing audio when
+        // they open Background Music, we won't interrupt it while we're waiting for them to click
+        // OK.
+        [AVCaptureDevice requestAccessForMediaType:AVMediaTypeAudio
+                                 completionHandler:^(BOOL granted) {
+            dispatch_async(dispatch_get_main_queue(), ^{
+                if (granted) {
+                    DebugMsg("BGMAppDelegate::applicationDidFinishLaunching: Permission granted");
+                    [self continueLaunchAfterInputDevicePermissionGranted];
+                } else {
+                    NSLog(@"BGMAppDelegate::applicationDidFinishLaunching: Permission denied");
+                    // If they don't accept, Background Music won't work at all and the only way to
+                    // fix it is in System Preferences, so show an error dialog with instructions.
+                    //
+                    // TODO: It would be nice if this dialog had a shortcut to open the System
+                    //       Preferences panel. See showSetDeviceAsDefaultError.
+                    [self showErrorMessage:@"Background Music needs permission to use microphones."
+                           informativeText:@"It uses a virtual microphone to access your system's "
+                                            "audio.\n\nYou can grant the permission by going to "
+                                            "System Preferences > Security and Privacy > "
+                                            "Microphone and checking the box for Background Music."
+                 exitAfterMessageDismissed:YES];
+                }
+            });
+        }];
+    }
+    else
+#endif
+    {
+        // We can change the device immediately on older versions of macOS because they don't
+        // require user permission for input devices.
+        [self continueLaunchAfterInputDevicePermissionGranted];
+    }
+}
+
+- (void) continueLaunchAfterInputDevicePermissionGranted {
     // Choose an output device for BGMApp to use to play audio.
     if (![self setInitialOutputDevice]) {
         return;
@@ -132,16 +178,16 @@ static NSString* const kOptShowDockIcon      = @"--show-dock-icon";
 
     autoPauseMusic = [[BGMAutoPauseMusic alloc] initWithAudioDevices:audioDevices
                                                         musicPlayers:musicPlayers];
-    
+
     [self setUpMainMenu];
-    
+
     xpcListener = [[BGMXPCListener alloc] initWithAudioDevices:audioDevices
                                   helperConnectionErrorHandler:^(NSError* error) {
-                                      NSLog(@"BGMAppDelegate::applicationDidFinishLaunching: (helperConnectionErrorHandler) "
-                                             "BGMXPCHelper connection error: %@",
-                                            error);
-                                      [self showXPCHelperErrorMessage:error];
-                                  }];
+        NSLog(@"BGMAppDelegate::continueLaunchAfterInputDevicePermissionGranted: "
+              "(helperConnectionErrorHandler) BGMXPCHelper connection error: %@",
+              error);
+        [self showXPCHelperErrorMessage:error];
+    }];
 }
 
 // Returns NO if (and only if) BGMApp is about to terminate because of a fatal error.
@@ -179,51 +225,73 @@ static NSString* const kOptShowDockIcon      = @"--show-dock-icon";
 
 // Sets the "Background Music" virtual audio device (BGMDevice) as the user's default audio device.
 - (void) setBGMDeviceAsDefault {
-    void (^setDefaultDevice)() = ^{
-        NSError* error = [audioDevices setBGMDeviceAsOSDefault];
+    NSError* error = [audioDevices setBGMDeviceAsOSDefault];
 
-        if (error) {
-            [self showSetDeviceAsDefaultError:error
-                                      message:@"Could not set the Background Music device as your"
-                                               "default audio device."
-                              informativeText:@"You might be able to change it yourself."];
-        }
-    };
-
-    // Skip this if we're compiling on a version of macOS before 10.14 as won't compile and it
-    // isn't needed.
-#if MAC_OS_X_VERSION_MAX_ALLOWED >= 101400  // MAC_OS_X_VERSION_10_14
-    if (@available(macOS 10.14, *)) {
-        // On macOS 10.14+ we need to get the user's permission to use input devices before we can
-        // use BGMDevice for playthrough (see BGMPlayThrough), so we wait until they've given it
-        // before making BGMDevice the default device. This way, if the user is playing audio when
-        // they open Background Music, we won't interrupt it while we're waiting for them to click
-        // OK.
-        //
-        // TODO: This isn't a perfect solution because, if the user takes too long to accept,
-        //       BGMPlayThrough will try to use BGMDevice again and log some errors.
-        [AVCaptureDevice requestAccessForMediaType:AVMediaTypeAudio
-                                 completionHandler:^(BOOL granted) {
-                                     if (granted) {
-                                         DebugMsg("BGMAppDelegate::setBGMDeviceAsDefault: "
-                                                  "Permission granted");
-                                         setDefaultDevice();
-                                     } else {
-                                         NSLog(@"BGMAppDelegate::setBGMDeviceAsDefault: "
-                                               "Permission denied");
-                                         // TODO: If they don't accept, Background Music won't work
-                                         //       at all and the only way to fix it is in System
-                                         //       Preferences, so we should show an error dialog
-                                         //       with instructions.
-                                     }
-                                 }];
+    if (error) {
+        [self showSetDeviceAsDefaultError:error
+                                  message:@"Could not set the Background Music device as your"
+                                           "default audio device."
+                          informativeText:@"You might be able to change it yourself."];
     }
-    else
-#endif
-    {
-        // We can change the device immediately on older versions of macOS because they don't
-        // require user permission for input devices.
-        setDefaultDevice();
+}
+
+- (void) menuWillOpen:(NSMenu*)menu {
+    if (@available(macOS 10.16, *)) {
+        // Set menu offset and check for any active menu items
+        float menuOffset = 12.0;
+        for (NSMenuItem* menuItem in self.bgmMenu.itemArray) {
+            if (menuItem.state == NSControlStateValueOn && menuItem.indentationLevel == 0) {
+                menuOffset += 10;
+                break;
+            }
+        }
+        
+        // Align volume output device and slider
+        for (NSView* subview in self.outputVolumeView.subviews) {
+            CGRect newSubview = subview.frame;
+            newSubview.origin.x = menuOffset;
+            subview.frame = newSubview;
+        }
+
+        // Align system sounds and app volumes
+        double appIconTitleOffset = 0;
+        for (NSMenuItem* menuItem in self.bgmMenu.itemArray) {
+            if (menuItem.view.subviews.count == 7 || menuItem.view.subviews.count == 3) {
+                NSTextField* appTitle;
+                NSImageView* appIcon;
+                
+                for (NSView* subview in menuItem.view.subviews) {
+                    if (menuItem.view.subviews.count == 3) {
+                        // System sounds
+                        if ([subview isKindOfClass:[NSTextField class]]) {
+                            appTitle = (NSTextField*)subview;
+                        }
+                        if ([subview isKindOfClass:[NSImageView class]]) {
+                            appIcon = (NSImageView*)subview;
+                        }
+                    } else if (menuItem.view.subviews.count == 7) {
+                        // App volumes
+                        if ([subview isKindOfClass:[BGMAVM_AppNameLabel class]]) {
+                            appTitle = (NSTextField*)subview;
+                        }
+                        if ([subview isKindOfClass:[BGMAVM_AppIcon class]]) {
+                            appIcon = (NSImageView*)subview;
+                        }
+                    }
+                }
+ 
+                if (appIconTitleOffset == 0) {
+                    appIconTitleOffset = appTitle.frame.origin.x - appIcon.frame.origin.x;
+                }
+                
+                CGRect newAppIcon = appIcon.frame;
+                newAppIcon.origin.x = menuOffset;
+                appIcon.frame = newAppIcon;
+                CGRect newAppTitle = appTitle.frame;
+                newAppTitle.origin.x = menuOffset + appIconTitleOffset;
+                appTitle.frame = newAppTitle;
+            }
+        }
     }
 }
 
@@ -251,6 +319,11 @@ static NSString* const kOptShowDockIcon      = @"--show-dock-icon";
                                                  aboutPanel:self.aboutPanel
                                       aboutPanelLicenseView:self.aboutPanelLicenseView];
 
+    // Enable/disable debug logging. Hidden unless you option-click the status bar icon.
+    debugLoggingMenuItem =
+        [[BGMDebugLoggingMenuItem alloc] initWithMenuItem:self.debugLoggingMenuItemUnwrapped];
+    [statusBarItem setDebugLoggingMenuItem:debugLoggingMenuItem];
+
     // Handle events about the main menu. (See the NSMenuDelegate methods below.)
     self.bgmMenu.delegate = self;
 }

BGMApp/BGMApp/BGMAppVolumes.h

@@ -18,6 +18,7 @@
 //  BGMApp
 //
 //  Copyright © 2016, 2017 Kyle Neideck
+//  Copyright © 2021 Marcus Wu
 //
 
 // Local Includes
@@ -35,7 +36,7 @@
                   bgmMenu:(NSMenu*)inMenu
             appVolumeView:(NSView*)inView;
 
-// Pass -1 for initialVolume or initialPan to leave the volume/pan at its default level.
+// Pass -1 for initialVolume or kAppPanNoValue for initialPan to leave the volume/pan at its default level.
 - (void) insertMenuItemForApp:(NSRunningApplication*)app
                 initialVolume:(int)volume
                    initialPan:(int)pan;
@@ -44,6 +45,9 @@
 
 - (void) removeAllAppVolumeMenuItems;
 
+- (BGMAppVolumeAndPan) getVolumeAndPanForApp:(NSRunningApplication*)app;
+- (void) setVolumeAndPan:(BGMAppVolumeAndPan)volumeAndPan forApp:(NSRunningApplication*)app;
+
 @end
 
 // Protocol for the UI custom classes

BGMApp/BGMApp/BGMAppVolumes.m

@@ -17,8 +17,10 @@
 //  BGMAppVolumes.m
 //  BGMApp
 //
-//  Copyright © 2016-2018 Kyle Neideck
+//  Copyright © 2016-2020 Kyle Neideck
 //  Copyright © 2017 Andrew Tonner
+//  Copyright © 2021 Marcus Wu
+//  Copyright © 2022 Jon Egan
 //
 
 // Self Include
@@ -124,6 +126,79 @@ static NSString* const kMoreAppsMenuTitle          = @"More Apps";
     }
 }
 
+- (NSMenuItem*) getMenuItemForApp:(NSRunningApplication*)app {
+    NSInteger lastAppVolumeMenuItemIndex = [self lastMenuItemIndex] - 2;
+
+    for (NSInteger i = [self firstMenuItemIndex]; i <= lastAppVolumeMenuItemIndex; i++) {
+        NSMenuItem* item = [bgmMenu itemAtIndex:i];
+        NSRunningApplication* itemApp = item.representedObject;
+        BGMAssert(itemApp, "!itemApp for %s", item.title.UTF8String);
+
+        if ([itemApp isEqual:app]) {
+            return item;
+        }
+    }
+    for (NSInteger i = 0; i < [moreAppsMenu numberOfItems]; i++) {
+        NSMenuItem* item = [moreAppsMenu itemAtIndex:i];
+        NSRunningApplication* itemApp = item.representedObject;
+        BGMAssert(itemApp, "!itemApp for %s", item.title.UTF8String);
+
+        if ([itemApp isEqual:app]) {
+            return item;
+        }
+    }
+
+    return nil;
+}
+
+- (BGMAppVolumeAndPan) getVolumeAndPanForApp:(NSRunningApplication*)app {
+    BGMAppVolumeAndPan result = {
+        .volume = -1,
+        .pan = kAppPanNoValue
+    };
+
+    NSMenuItem *item = [self getMenuItemForApp:app];
+
+    if (item == nil) {
+        return result;
+    }
+
+    for (NSView* subview in item.view.subviews) {
+        // Get the volume.
+        if ([subview isKindOfClass:[BGMAVM_VolumeSlider class]]) {
+            result.volume = [(BGMAVM_VolumeSlider*)subview intValue];
+        }
+
+        // Get the pan position.
+        if ([subview isKindOfClass:[BGMAVM_PanSlider class]]) {
+            result.pan = [(BGMAVM_PanSlider*)subview intValue];
+        }
+    }
+
+    return result;
+}
+
+- (void) setVolumeAndPan:(BGMAppVolumeAndPan)volumeAndPan forApp:(NSRunningApplication*)app {
+    NSMenuItem *item = [self getMenuItemForApp:app];
+
+    if (item == nil) {
+        return;
+    }
+
+    for (NSView* subview in item.view.subviews) {
+        // Set the volume.
+        if (volumeAndPan.volume != -1 && [subview isKindOfClass:[BGMAVM_VolumeSlider class]]) {
+            [(BGMAVM_VolumeSlider*)subview setRelativeVolume:volumeAndPan.volume];
+        }
+
+        // Set the pan position.
+        if (volumeAndPan.pan != kAppPanNoValue && [subview isKindOfClass:[BGMAVM_PanSlider class]]) {
+            [(BGMAVM_PanSlider*)subview setPanPosition:volumeAndPan.pan];
+        }
+    }
+
+}
+
 // Create a blank menu item to copy as a template.
 - (NSMenuItem*) createBlankAppVolumeMenuItem {
     NSMenuItem* menuItem = [[NSMenuItem alloc] initWithTitle:@"" action:nil keyEquivalent:@""];
@@ -143,7 +218,7 @@ static NSString* const kMoreAppsMenuTitle          = @"More Apps";
         }
 
         // Set the pan position.
-        if (pan != -1 && [subview isKindOfClass:[BGMAVM_PanSlider class]]) {
+        if (pan != kAppPanNoValue && [subview isKindOfClass:[BGMAVM_PanSlider class]]) {
             [(BGMAVM_PanSlider*)subview setPanPosition:pan];
         }
     }
@@ -196,20 +271,32 @@ static NSString* const kMoreAppsMenuTitle          = @"More Apps";
     
     BGMAssert(button, "!button");
     BGMAssert(menuItem, "!menuItem");
-    
+
     CGFloat width = menuItem.view.frame.size.width;
-    CGFloat height = menuItem.view.frame.size.height;
-    
 #if DEBUG
-    const char* appName = [((NSRunningApplication*)menuItem.representedObject).localizedName UTF8String];
+    CGFloat height = menuItem.view.frame.size.height;
 #endif
 
+    const char* appName =
+        [((NSRunningApplication*)menuItem.representedObject).localizedName UTF8String];
+
     // Using this function (instead of just ==) shouldn't be necessary, but just in case.
+#if DEBUG
     BOOL(^nearEnough)(CGFloat x, CGFloat y) = ^BOOL(CGFloat x, CGFloat y) {
         return fabs(x - y) < 0.01;  // We don't need much precision.
     };
+#endif
     
-    if (nearEnough(button.frameCenterRotation, 0.0)) {
+    bool allSubviewsShowing = true;
+    for (NSView* subview in menuItem.view.subviews) {
+        if (subview.hidden) {
+            allSubviewsShowing = false;
+            break;
+        }
+        //DebugMsg("BGMAppVolumes:: subview hash / hidden: (%lu) / (%hhd)", (unsigned long)subview.hash, subview.hidden);
+    }
+
+    if (allSubviewsShowing) {
         // Hide extra controls
         DebugMsg("BGMAppVolumes::showHideExtraControls: Hiding extra controls (%s)", appName);
         
@@ -241,7 +328,7 @@ static NSString* const kMoreAppsMenuTitle          = @"More Apps";
         menuItem.view.frameSize = NSMakeSize(width, appVolumeViewFullHeight);
         // Turn the button rightside up so the arrowhead points up.
         button.frameCenterRotation = 0.0;
-        // Move the button down slightly, back to it's original position.
+        // Move the button down slightly, back to its original position.
         [button setFrameOrigin:NSMakePoint(button.frame.origin.x, button.frame.origin.y + 1)];
 
         // Set all of the UI elements in the menu item to "not hidden" for accessibility clients.
@@ -446,4 +533,3 @@ static NSString* const kMoreAppsMenuTitle          = @"More Apps";
 }
 
 @end
-

BGMApp/BGMApp/BGMAppVolumesController.h

@@ -18,6 +18,7 @@
 //  BGMApp
 //
 //  Copyright © 2017 Kyle Neideck
+//  Copyright © 2021 Marcus Wu
 //
 
 // Local Includes
@@ -29,6 +30,11 @@
 
 #pragma clang assume_nonnull begin
 
+typedef struct BGMAppVolumeAndPan {
+    int volume;
+    int pan;
+} BGMAppVolumeAndPan;
+
 @interface BGMAppVolumesController : NSObject
 
 - (id) initWithMenu:(NSMenu*)menu
@@ -45,6 +51,9 @@ forAppWithProcessID:(pid_t)processID
     forAppWithProcessID:(pid_t)processID
                bundleID:(NSString* __nullable)bundleID;
 
+- (BGMAppVolumeAndPan) getVolumeAndPanForApp:(NSRunningApplication *)app;
+- (void) setVolumeAndPan:(BGMAppVolumeAndPan)volumeAndPan forApp:(NSRunningApplication*)app;
+
 @end
 
 #pragma clang assume_nonnull end

BGMApp/BGMApp/BGMAppVolumesController.mm

@@ -19,6 +19,7 @@
 //
 //  Copyright © 2017, 2018 Kyle Neideck
 //  Copyright © 2017 Andrew Tonner
+//  Copyright © 2021 Marcus Wu
 //
 
 // Self Include
@@ -40,11 +41,6 @@
 
 #pragma clang assume_nonnull begin
 
-typedef struct BGMAppVolumeAndPan {
-    int volume;
-    int pan;
-} BGMAppVolumeAndPan;
-
 @implementation BGMAppVolumesController {
     // The App Volumes UI.
     BGMAppVolumes* appVolumes;
@@ -104,11 +100,25 @@ typedef struct BGMAppVolumeAndPan {
     }
 }
 
+- (BGMAppVolumeAndPan) getVolumeAndPanForApp:(NSRunningApplication *)app {
+    return [appVolumes getVolumeAndPanForApp:app];
+}
+
+- (void) setVolumeAndPan:(BGMAppVolumeAndPan)volumeAndPan forApp:(NSRunningApplication*)app {
+    [appVolumes setVolumeAndPan:volumeAndPan forApp:app];
+    if (volumeAndPan.volume != -1) {
+        [self setVolume:volumeAndPan.volume forAppWithProcessID:app.processIdentifier bundleID:app.bundleIdentifier];
+    }
+    if (volumeAndPan.pan != kAppPanNoValue) {
+        [self setPanPosition:volumeAndPan.pan forAppWithProcessID:app.processIdentifier bundleID:app.bundleIdentifier];
+    }
+}
+
 - (BGMAppVolumeAndPan) getVolumeAndPanForApp:(NSRunningApplication*)app
                                  fromVolumes:(const CACFArray&)volumes {
     BGMAppVolumeAndPan volumeAndPan = {
         .volume = -1,
-        .pan = -1
+        .pan = kAppPanNoValue
     };
 
     for (UInt32 i = 0; i < volumes.GetNumberItems(); i++) {

BGMApp/BGMApp/BGMAudioDevice.cpp

@@ -48,7 +48,7 @@ BGMAudioDevice::BGMAudioDevice(const CAHALAudioDevice& inDevice)
 :
     BGMAudioDevice(inDevice.GetObjectID())
 {
-};
+}
 
 BGMAudioDevice::~BGMAudioDevice()
 {
@@ -57,6 +57,8 @@ BGMAudioDevice::~BGMAudioDevice()
 bool    BGMAudioDevice::CanBeOutputDeviceInBGMApp() const
 {
     CFStringRef uid = CopyDeviceUID();
+    assert(uid != nullptr);
+
     bool isNullDevice = CFEqual(uid, CFSTR(kBGMNullDeviceUID));
     CFRelease(uid);
 
@@ -81,7 +83,7 @@ bool    BGMAudioDevice::HasSettableMasterVolume(AudioObjectPropertyScope inScope
 bool    BGMAudioDevice::HasSettableVirtualMasterVolume(AudioObjectPropertyScope inScope) const
 {
     AudioObjectPropertyAddress virtualMasterVolumeAddress = {
-        kAudioHardwareServiceDeviceProperty_VirtualMasterVolume,
+        kAudioHardwareServiceDeviceProperty_VirtualMainVolume,
         inScope,
         kAudioObjectPropertyElementMaster
     };
@@ -220,7 +222,7 @@ bool    BGMAudioDevice::GetVirtualMasterVolumeScalar(AudioObjectPropertyScope in
                                                      Float32& outVirtualMasterVolume) const
 {
     AudioObjectPropertyAddress virtualMasterVolumeAddress = {
-        kAudioHardwareServiceDeviceProperty_VirtualMasterVolume,
+        kAudioHardwareServiceDeviceProperty_VirtualMainVolume,
         inScope,
         kAudioObjectPropertyElementMaster
     };
@@ -265,7 +267,7 @@ bool    BGMAudioDevice::SetVirtualMasterVolumeScalar(AudioObjectPropertyScope in
         bool didGetVirtualMasterBalance = GetVirtualMasterBalance(inScope, virtualMasterBalance);
 
         AudioObjectPropertyAddress virtualMasterVolumeAddress = {
-            kAudioHardwareServiceDeviceProperty_VirtualMasterVolume,
+            kAudioHardwareServiceDeviceProperty_VirtualMainVolume,
             inScope,
             kAudioObjectPropertyElementMaster
         };
@@ -277,7 +279,7 @@ bool    BGMAudioDevice::SetVirtualMasterVolumeScalar(AudioObjectPropertyScope in
 
         // Reset the balance
         AudioObjectPropertyAddress virtualMasterBalanceAddress = {
-            kAudioHardwareServiceDeviceProperty_VirtualMasterBalance,
+            kAudioHardwareServiceDeviceProperty_VirtualMainBalance,
             inScope,
             kAudioObjectPropertyElementMaster
         };
@@ -310,7 +312,7 @@ bool    BGMAudioDevice::GetVirtualMasterBalance(AudioObjectPropertyScope inScope
                                                 Float32& outVirtualMasterBalance) const
 {
     AudioObjectPropertyAddress virtualMasterBalanceAddress = {
-        kAudioHardwareServiceDeviceProperty_VirtualMasterBalance,
+        kAudioHardwareServiceDeviceProperty_VirtualMainBalance,
         inScope,
         kAudioObjectPropertyElementMaster
     };
@@ -340,6 +342,9 @@ bool    BGMAudioDevice::IsBGMDevice(bool inIncludeUISoundsInstance) const
     {
         // Check the device's UID to see whether it's BGMDevice.
         CFStringRef uid = CopyDeviceUID();
+        if (uid == nullptr) {
+            return isBGMDevice;
+        }
 
         isBGMDevice =
             CFEqual(uid, CFSTR(kBGMDeviceUID)) ||

BGMApp/BGMApp/BGMAudioDevice.h

@@ -16,7 +16,7 @@
 //  BGMAudioDevice.h
 //  BGMApp
 //
-//  Copyright © 2017 Kyle Neideck
+//  Copyright © 2017, 2020 Kyle Neideck
 //
 //  A HAL audio device. Note that this class's only state is the AudioObjectID of the device.
 //
@@ -59,7 +59,8 @@ public:
                        operator AudioObjectID() const { return GetObjectID(); }
 
     /*!
-     @return True if this device is BGMDevice. (Specifically, the main instance of BGMDevice.)
+     @return True if this device is BGMDevice. (Specifically, the main instance of BGMDevice, not
+             the instance used for UI sounds.)
      @throws CAException If the HAL returns an error when queried.
      */
     bool               IsBGMDevice() const { return IsBGMDevice(false); };

BGMApp/BGMApp/BGMAudioDeviceManager.mm

@@ -378,8 +378,14 @@
     
     @try {
         gotLock = [stateLock tryLock];
-        
-        if (gotLock) {
+
+        BOOL isBigSur = NO;
+        if (@available(macOS 11.0, *)) {
+            isBigSur = YES;
+        }
+
+        // Always start playthrough asynchronously. Temp workaround for deadlock on Big Sur.
+        if (!isBigSur && gotLock) {
             BGMPlayThrough& pt = (forUISoundsDevice ? playThrough_UISounds : playThrough);
 
             // Playthrough might not have been notified that BGMDevice is starting yet, so make sure

BGMApp/BGMApp/BGMBackgroundMusicDevice.cpp

@@ -17,7 +17,7 @@
 //  BGMBackgroundMusicDevice.cpp
 //  BGMApp
 //
-//  Copyright © 2016, 2017 Kyle Neideck
+//  Copyright © 2016-2019 Kyle Neideck
 //  Copyright © 2017 Andrew Tonner
 //
 
@@ -239,7 +239,13 @@ BGMBackgroundMusicDevice::ResponsibleBundleIDsOf(CACFString inParentBundleID)
         // Discord
         { "com.hnc.Discord", { "com.hnc.Discord.helper" } },
         // Skype
-        { "com.skype.skype", { "com.skype.skype.Helper" } }
+        { "com.skype.skype", { "com.skype.skype.Helper" } },
+        // Google Chrome
+        { "com.google.Chrome", { "com.google.Chrome.helper" } },
+        // Microsoft Edge
+        { "com.microsoft.edgemac", { "com.microsoft.edgemac.helper" } },
+        // Arc
+        { "company.thebrowser.Browser", { "company.thebrowser.browser.helper" } }
     };
 
     // Parallels' VM "dock helper" apps have bundle IDs like

BGMApp/BGMApp/BGMDebugLoggingMenuItem.h

@@ -0,0 +1,48 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  BGMDebugLoggingMenuItem.h
+//  BGMApp
+//
+//  Copyright © 2020 Kyle Neideck
+//
+//  A menu item in the main menu that enables/disables debug logging. Only visible if you hold the
+//  option down when you click the status bar icon to reveal the main menu.
+//
+//  TODO: It would be better to have this menu item in the Preferences menu (maybe in an Advanced
+//        section) and always visible, but first we'd need to add something that tells the user how
+//        to view the log messages. Or better yet, something that automatically opens them.
+//
+
+// System Includes
+#import <Cocoa/Cocoa.h>
+
+
+#pragma clang assume_nonnull begin
+
+@interface BGMDebugLoggingMenuItem : NSObject
+
+- (instancetype) initWithMenuItem:(NSMenuItem*)menuItem;
+
+// True if the main menu is showing hidden items/options because the user held the option key when
+// they clicked the icon. This class makes the debug logging menu item visible if this property has
+// been set true or if debug logging is enabled.
+@property (nonatomic) BOOL menuShowingExtraOptions;
+
+@end
+
+#pragma clang assume_nonnull end
+

BGMApp/BGMApp/BGMDebugLoggingMenuItem.m

@@ -0,0 +1,73 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  BGMDebugLoggingMenuItem.m
+//  BGMApp
+//
+//  Copyright © 2020 Kyle Neideck
+//
+
+// Self Include
+#import "BGMDebugLoggingMenuItem.h"
+
+// PublicUtility Includes
+#import "BGMDebugLogging.h"
+#import "CADebugMacros.h"
+
+
+#pragma clang assume_nonnull begin
+
+@implementation BGMDebugLoggingMenuItem {
+    NSMenuItem* _menuItem;
+    BOOL _menuShowingExtraOptions;
+}
+
+- (instancetype) initWithMenuItem:(NSMenuItem*)menuItem {
+    if ((self = [super init])) {
+        _menuItem = menuItem;
+        _menuItem.state =
+                BGMDebugLoggingIsEnabled() ? NSControlStateValueOn : NSControlStateValueOff;
+
+        [self setMenuShowingExtraOptions:NO];
+
+        // Enable/disable debug logging when the menu item is clicked.
+        menuItem.target = self;
+        menuItem.action = @selector(toggleDebugLogging);
+    }
+
+    return self;
+}
+
+- (void) setMenuShowingExtraOptions:(BOOL)showingExtra {
+    _menuShowingExtraOptions = showingExtra;
+    _menuItem.hidden = !BGMDebugLoggingIsEnabled() && !showingExtra;
+
+    DebugMsg("BGMDebugLoggingMenuItem::menuShowingExtraOptions: %s the menu item",
+             _menuItem.hidden ? "Hiding" : "Showing");
+}
+
+- (void) toggleDebugLogging {
+    BGMSetDebugLoggingEnabled(!BGMDebugLoggingIsEnabled());
+    _menuItem.state = BGMDebugLoggingIsEnabled() ? NSControlStateValueOn : NSControlStateValueOff;
+
+    DebugMsg("BGMDebugLoggingMenuItem::toggleDebugLogging: Debug logging %s",
+             BGMDebugLoggingIsEnabled() ? "enabled" : "disabled");
+}
+
+@end
+
+#pragma clang assume_nonnull end
+

BGMApp/BGMApp/BGMOutputVolumeMenuItem.mm

@@ -211,36 +211,53 @@ NSString* const __nonnull      kGenericOutputDeviceName = @"Output Device";
 // datasource, the device's name is set as this menu item's tooltip. Falls back to a generic name if
 // the device returns an error when queried.
 - (void) updateLabelAndToolTip {
-    BOOL didSetLabel = NO;
-
-    try {
-        if (outputDevice.HasDataSourceControl(kScope, kMasterChannel)) {
-            // The device has datasources, so use the current datasource's name like macOS does.
-            UInt32 dataSourceID = outputDevice.GetCurrentDataSourceID(kScope, kMasterChannel);
-
-            deviceLabel.stringValue =
-                (__bridge_transfer NSString*)outputDevice.CopyDataSourceNameForID(kScope,
-                                                                                  kMasterChannel,
-                                                                                  dataSourceID);
-            didSetLabel = YES;  // So we know not to change the text if setting the tooltip fails.
-
-            // Set the tooltip of the menu item (the container) rather than the label because menu
-            // items' tooltips will still appear when a different app is focused and, as far as I
-            // know, BGMApp should never be the foreground app.
-            self.toolTip = (__bridge_transfer NSString*)outputDevice.CopyName();
-        } else {
-            deviceLabel.stringValue = (__bridge_transfer NSString*)outputDevice.CopyName();
-            self.toolTip = nil;
-        }
-    } catch (const CAException& e) {
-        BGMLogException(e);
-
-        // The device returned an error, so set the label to a generic device name, since we don't
-        // want to leave it set to the previous device's name.
+    if (outputDevice.GetObjectID() == kAudioObjectUnknown) {
+        DebugMsg("BGMOutputVolumeMenuItem::updateLabelAndToolTip: Output device unknown. Using the "
+                 "generic label.");
         self.toolTip = nil;
+        deviceLabel.stringValue = kGenericOutputDeviceName;
+    } else {
+        BOOL didSetLabel = NO;
 
-        if (!didSetLabel) {
-            deviceLabel.stringValue = kGenericOutputDeviceName;
+        DebugMsg("BGMOutputVolumeMenuItem::updateLabelAndToolTip: Output device: %u",
+                 outputDevice.GetObjectID());
+
+        try {
+            if (outputDevice.HasDataSourceControl(kScope, kMasterChannel)) {
+                DebugMsg("BGMOutputVolumeMenuItem::updateLabelAndToolTip: Getting data source ID");
+                // The device has datasources, so use the current datasource's name like macOS does.
+                UInt32 dataSourceID = outputDevice.GetCurrentDataSourceID(kScope, kMasterChannel);
+
+                DebugMsg("BGMOutputVolumeMenuItem::updateLabelAndToolTip: "
+                         "Getting name for data source %u",
+                         dataSourceID);
+                deviceLabel.stringValue =
+                    (__bridge_transfer NSString*)outputDevice.CopyDataSourceNameForID(
+                        kScope, kMasterChannel, dataSourceID);
+
+                // So we know not to change the text if setting the tooltip fails.
+                didSetLabel = YES;
+
+                DebugMsg("BGMOutputVolumeMenuItem::updateLabelAndToolTip: Getting device name");
+                // Set the tooltip of the menu item (the container) rather than the label because
+                // menu items' tooltips will still appear when a different app is focused and, as
+                // far as I know, BGMApp should never be the foreground app.
+                self.toolTip = (__bridge_transfer NSString*)outputDevice.CopyName();
+            } else {
+                DebugMsg("BGMOutputVolumeMenuItem::updateLabelAndToolTip: Getting device name");
+                deviceLabel.stringValue = (__bridge_transfer NSString*)outputDevice.CopyName();
+                self.toolTip = nil;
+            }
+        } catch (const CAException& e) {
+            BGMLogException(e);
+
+            // The device returned an error, so set the label to a generic device name, since we
+            // don't want to leave it set to the previous device's name.
+            self.toolTip = nil;
+
+            if (!didSetLabel) {
+                deviceLabel.stringValue = kGenericOutputDeviceName;
+            }
         }
     }
 

BGMApp/BGMApp/BGMPlayThrough.cpp

@@ -17,7 +17,7 @@
 //  BGMPlayThrough.cpp
 //  BGMApp
 //
-//  Copyright © 2016, 2017 Kyle Neideck
+//  Copyright © 2016, 2017, 2020 Kyle Neideck
 //
 
 // Self Include
@@ -28,7 +28,6 @@
 #include "BGM_Utils.h"
 
 // PublicUtility Includes
-#include "CAAtomic.h"
 #include "CAHALAudioSystemObject.h"
 #include "CAPropertyAddress.h"
 
@@ -57,9 +56,20 @@ BGMPlayThrough::BGMPlayThrough(BGMAudioDevice inInputDevice, BGMAudioDevice inOu
 
 BGMPlayThrough::~BGMPlayThrough()
 {
+    CAMutex::Locker stateLocker(mStateMutex);
+
     BGMLogAndSwallowExceptionsMsg("BGMPlayThrough::~BGMPlayThrough", "Deactivate", [&]() {
         Deactivate();
     });
+
+    // If one of the IOProcs failed to stop, CoreAudio could (at least in theory) still call it
+    // after this point. This isn't a solution, but calling DeallocateBuffer instead of letting it
+    // deallocate itself should at least make the error less likely to cause a segfault, since
+    // DeallocateBuffer takes the buffer locks and sets mBuffer to null.
+    //
+    // TODO: It probably wouldn't be too hard to fix this properly by giving the IOProcs weak refs
+    //       to the BGMPlayThrough object instead of raw pointers.
+    DeallocateBuffer();
     
     if(mOutputDeviceIOProcSemaphore != SEMAPHORE_NULL)
     {
@@ -97,7 +107,7 @@ void    BGMPlayThrough::Init(BGMAudioDevice inInputDevice, BGMAudioDevice inOutp
     catch (...)
     {
         // Clean up.
-        mBuffer.Deallocate();
+        DeallocateBuffer();
         throw;
     }
 }
@@ -178,7 +188,7 @@ void    BGMPlayThrough::Deactivate()
         DebugMsg("BGMPlayThrough::Deactivate: Deactivating playthrough");
         
         bool inputDeviceIsBGMDevice = true;
-        
+
         CATry
         inputDeviceIsBGMDevice = mInputDevice.IsBGMDeviceInstance();
         CACatch
@@ -231,13 +241,29 @@ void    BGMPlayThrough::AllocateBuffer()
         Throw(CAException(kAudioHardwareUnsupportedOperationError));
     }
     
+    // Need to lock the buffer mutexes to make sure the IOProcs aren't accessing it. The order is
+    // important here. We always lock them in the same order to prevent deadlocks.
+    CAMutex::Locker lockerInput(mBufferInputMutex);
+    CAMutex::Locker lockerOutput(mBufferOutputMutex);
+
+    mBuffer = std::unique_ptr<CARingBuffer>(new CARingBuffer);
+
     // The calculation for the size of the buffer is from Apple's CAPlayThrough.cpp sample code
     //
     // TODO: Test playthrough with hardware with more than 2 channels per frame, a sample (virtual) format other than
     //       32-bit floats and/or an IO buffer size other than 512 frames
-    mBuffer.Allocate(outputFormat[0].mChannelsPerFrame,
-                     outputFormat[0].mBytesPerFrame,
-                     mOutputDevice.GetIOBufferSize() * 20);
+    mBuffer->Allocate(outputFormat[0].mChannelsPerFrame,
+                      outputFormat[0].mBytesPerFrame,
+                      mOutputDevice.GetIOBufferSize() * 20);
+}
+
+void    BGMPlayThrough::DeallocateBuffer()
+{
+    // Need to lock the buffer mutexes to make sure the IOProcs aren't accessing it. The order is
+    // important here. We always lock them in the same order to prevent deadlocks.
+    CAMutex::Locker lockerInput(mBufferInputMutex);
+    CAMutex::Locker lockerOutput(mBufferOutputMutex);
+    mBuffer = nullptr;  // Note that the buffer's destructor will deallocate it.
 }
 
 void    BGMPlayThrough::CreateIOProcIDs()
@@ -569,20 +595,21 @@ OSStatus    BGMPlayThrough::WaitForOutputDeviceToStart() noexcept
     while((theError != KERN_SUCCESS) &&         // Signalled from the IOProc.
           (state == IOState::Starting) &&       // IO state changed.
           (waitedNsec < kStartIOTimeoutNsec));  // Timed out.
-    
-#if DEBUG
-    UInt64 startedBy = mach_absolute_time();
-    
-    struct mach_timebase_info baseInfo = { 0, 0 };
-    mach_timebase_info(&baseInfo);
-    UInt64 base = baseInfo.numer / baseInfo.denom;
-    
-    DebugMsg("BGMPlayThrough::WaitForOutputDeviceToStart: Started %f ms after notification, %f ms "
-             "after entering WaitForOutputDeviceToStart.",
-             static_cast<Float64>(startedBy - mToldOutputDeviceToStartAt) * base / NSEC_PER_MSEC,
-             static_cast<Float64>(startedBy - startedAt) * base / NSEC_PER_MSEC);
-#endif
-    
+
+    if(BGMDebugLoggingIsEnabled())
+    {
+        UInt64 startedBy = mach_absolute_time();
+
+        struct mach_timebase_info baseInfo = { 0, 0 };
+        mach_timebase_info(&baseInfo);
+        UInt64 base = baseInfo.numer / baseInfo.denom;
+
+        DebugMsg("BGMPlayThrough::WaitForOutputDeviceToStart: Started %f ms after notification, %f "
+                 "ms after entering WaitForOutputDeviceToStart.",
+                 static_cast<Float64>(startedBy - mToldOutputDeviceToStartAt) * base / NSEC_PER_MSEC,
+                 static_cast<Float64>(startedBy - startedAt) * base / NSEC_PER_MSEC);
+    }
+
     // Figure out which error code to return.
     switch (theError)
     {
@@ -604,7 +631,7 @@ OSStatus    BGMPlayThrough::WaitForOutputDeviceToStart() noexcept
 
 // Release any threads waiting for the output device to start. This function doesn't take mStateMutex
 // because it gets called on the IO thread, which is realtime priority.
-void    BGMPlayThrough::ReleaseThreadsWaitingForOutputToStart() const
+void    BGMPlayThrough::ReleaseThreadsWaitingForOutputToStart()
 {
     if(mActive)
     {
@@ -612,13 +639,10 @@ void    BGMPlayThrough::ReleaseThreadsWaitingForOutputToStart() const
         
         if(semaphore != SEMAPHORE_NULL)
         {
-            DebugMsg("BGMPlayThrough::ReleaseThreadsWaitingForOutputToStart: Releasing waiting threads");
+            mRTLogger.LogReleasingWaitingThreads();
+
             kern_return_t theError = semaphore_signal_all(semaphore);
-            
-            // TODO: Tell another thread to log this error, since we might be on a realtime thread.
-            BGM_Utils::LogIfMachError("BGMPlayThrough::ReleaseThreadsWaitingForOutputToStart",
-                                      "semaphore_signal_all",
-                                      theError);
+            mRTLogger.LogIfMachError_ReleaseWaitingThreadsSignal(theError);
         }
     }
 }
@@ -867,12 +891,15 @@ void    BGMPlayThrough::HandleBGMDeviceIsRunning(BGMPlayThrough* refCon)
                 isRunningSomewhereOtherThanBGMApp =
                     IsRunningSomewhereOtherThanBGMApp(refCon->mInputDevice);
             });
+
+            DebugMsg("BGMPlayThrough::HandleBGMDeviceIsRunning: "
+                     "BGMDevice is %srunning somewhere other than BGMApp",
+                     isRunningSomewhereOtherThanBGMApp ? "" : "not ");
             
             if(isRunningSomewhereOtherThanBGMApp)
             {
-#if DEBUG
                 refCon->mToldOutputDeviceToStartAt = mach_absolute_time();
-#endif
+
                 // TODO: Handle expected exceptions (mostly CAExceptions from PublicUtility classes) in Start.
                 //       For any that can't be handled sensibly in Start, catch them here and retry a few
                 //       times (with a very short delay) before handling them by showing an unobtrusive error
@@ -906,15 +933,14 @@ void    BGMPlayThrough::HandleBGMDeviceIsRunningSomewhereOtherThanBGMApp(BGMPlay
 // static
 bool    BGMPlayThrough::IsRunningSomewhereOtherThanBGMApp(const BGMAudioDevice& inBGMDevice)
 {
-    return CFBooleanGetValue(
-        static_cast<CFBooleanRef>(
-            inBGMDevice.GetPropertyData_CFType(kBGMRunningSomewhereOtherThanBGMAppAddress)));
+    auto type = inBGMDevice.GetPropertyData_CFType(kBGMRunningSomewhereOtherThanBGMAppAddress);
+    return type && CFBooleanGetValue(static_cast<CFBooleanRef>(type));
 }
 
 #pragma mark IOProcs
 
-// Note that the IOProcs will very likely not run on the same thread and that they intentionally don't
-// lock any mutexes.
+// Note that the IOProcs will very likely not run on the same thread and that they intentionally
+// only lock mutexes around their use of mBuffer.
 
 // static
 OSStatus    BGMPlayThrough::InputDeviceIOProc(AudioObjectID           inDevice,
@@ -932,6 +958,7 @@ OSStatus    BGMPlayThrough::InputDeviceIOProc(AudioObjectID           inDevice,
     
     IOState state;
     UpdateIOProcState("InputDeviceIOProc",
+                      refCon->mRTLogger,
                       refCon->mInputDeviceIOProcState,
                       refCon->mInputDeviceIOProcID,
                       refCon->mInputDevice,
@@ -952,16 +979,30 @@ OSStatus    BGMPlayThrough::InputDeviceIOProc(AudioObjectID           inDevice,
     
     UInt32 framesToStore = inInputData->mBuffers[0].mDataByteSize / (SizeOf32(Float32) * 2);
 
-    CARingBufferError err =
-        refCon->mBuffer.Store(inInputData,
-                              framesToStore,
-                              static_cast<CARingBuffer::SampleTime>(inInputTime->mSampleTime));
-    
-    HandleRingBufferError(err, "InputDeviceIOProc", "mBuffer.Store");
-    
-    CAMemoryBarrier();
-    refCon->mLastInputSampleTime = inInputTime->mSampleTime;
-    
+    // See the comments in OutputDeviceIOProc where it locks mBufferOutputMutex.
+    CAMutex::Tryer tryer(refCon->mBufferInputMutex);
+
+    // Disable a warning about accessing mBuffer without holding both mBufferInputMutex and
+    // mBufferOutputMutex. Explained further in OutputDeviceIOProc.
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wthread-safety"
+    if(tryer.HasLock() && refCon->mBuffer)
+    {
+        CARingBufferError err =
+                refCon->mBuffer->Store(inInputData,
+                                       framesToStore,
+                                       static_cast<CARingBuffer::SampleTime>(
+                                               inInputTime->mSampleTime));
+#pragma clang diagnostic pop
+        refCon->mRTLogger.LogIfRingBufferError_Store(err);
+
+        refCon->mLastInputSampleTime = inInputTime->mSampleTime;
+    }
+    else
+    {
+        refCon->mRTLogger.LogRingBufferUnavailable("InputDeviceIOProc", tryer.HasLock());
+    }
+
     return noErr;
 }
 
@@ -974,13 +1015,14 @@ OSStatus    BGMPlayThrough::OutputDeviceIOProc(AudioObjectID           inDevice,
                                                const AudioTimeStamp*   inOutputTime,
                                                void* __nullable        inClientData)
 {
-    #pragma unused (inDevice, inNow, inInputData, inInputTime, inOutputTime)
+    #pragma unused (inDevice, inNow, inInputData, inInputTime)
     
     // refCon (reference context) is the instance that created the IOProc
     BGMPlayThrough* const refCon = static_cast<BGMPlayThrough*>(inClientData);
     
     IOState state;
     const bool didChangeState = UpdateIOProcState("OutputDeviceIOProc",
+                                                  refCon->mRTLogger,
                                                   refCon->mOutputDeviceIOProcState,
                                                   refCon->mOutputDeviceIOProcID,
                                                   refCon->mOutputDevice,
@@ -989,6 +1031,7 @@ OSStatus    BGMPlayThrough::OutputDeviceIOProc(AudioObjectID           inDevice,
     if(state == IOState::Stopped || state == IOState::Stopping)
     {
         // Return early, since we just asked to stop. (Or something really weird is going on.)
+        FillWithSilence(outOutputData);
         return noErr;
     }
     
@@ -1008,8 +1051,7 @@ OSStatus    BGMPlayThrough::OutputDeviceIOProc(AudioObjectID           inDevice,
     if(refCon->mLastInputSampleTime == -1)
     {
         // Return early, since we don't have any data to output yet.
-        //
-        // TODO: Write silence to outOutputData here
+        FillWithSilence(outOutputData);
         return noErr;
     }
     
@@ -1020,13 +1062,8 @@ OSStatus    BGMPlayThrough::OutputDeviceIOProc(AudioObjectID           inDevice,
         refCon->mInToOutSampleOffset = inOutputTime->mSampleTime - refCon->mLastInputSampleTime;
         
         // Log if we dropped frames
-        if(refCon->mFirstInputSampleTime != refCon->mLastInputSampleTime)
-        {
-            DebugMsg("BGMPlayThrough::OutputDeviceIOProc: Dropped %f frames before output started. %s%f %s%f",
-                     (refCon->mLastInputSampleTime - refCon->mFirstInputSampleTime),
-                     "mFirstInputSampleTime=", refCon->mFirstInputSampleTime,
-                     "mLastInputSampleTime=", refCon->mLastInputSampleTime);
-        }
+        refCon->mRTLogger.LogIfDroppedFrames(refCon->mFirstInputSampleTime,
+                                             refCon->mLastInputSampleTime);
     }
     
     CARingBuffer::SampleTime readHeadSampleTime =
@@ -1035,47 +1072,93 @@ OSStatus    BGMPlayThrough::OutputDeviceIOProc(AudioObjectID           inDevice,
         static_cast<CARingBuffer::SampleTime>(refCon->mLastInputSampleTime);
     
     UInt32 framesToOutput = outOutputData->mBuffers[0].mDataByteSize / (SizeOf32(Float32) * 2);
-    
-    // Very occasionally (at least for me) our read head gets ahead of input, i.e. we haven't received any new input since
-    // this IOProc was last called, and we have to recalculate its position. I figure this might be caused by clock drift
-    // but I'm really not sure. It also happens if the input or output sample times are restarted from zero.
-    //
-    // We also recalculate the offset if the read head is outside of the ring buffer. This happens for example when you plug
-    // in or unplug headphones, which causes the output sample times to be restarted from zero.
-    //
-    // The vast majority of the time, just using lastInputSampleTime as the read head time instead of the one we calculate
-    // would work fine (and would also account for the above).
-    SInt64 bufferStartTime, bufferEndTime;
-    CARingBufferError err = refCon->mBuffer.GetTimeBounds(bufferStartTime, bufferEndTime);
-    bool outOfBounds = false;
-    if(err == kCARingBufferError_OK)
-    {
-        outOfBounds = (readHeadSampleTime < bufferStartTime) || (readHeadSampleTime - framesToOutput > bufferEndTime);
-    }
-    if(lastInputSampleTime < readHeadSampleTime || outOfBounds)
-    {
-        DebugMsg("BGMPlayThrough::OutputDeviceIOProc: No input samples ready at output sample time. %s%lld %s%lld %s%f",
-                 "lastInputSampleTime=", lastInputSampleTime,
-                 "readHeadSampleTime=", readHeadSampleTime,
-                 "mInToOutSampleOffset=", refCon->mInToOutSampleOffset);
-        
-        // Recalculate the in-to-out offset and read head
-        refCon->mInToOutSampleOffset = inOutputTime->mSampleTime - lastInputSampleTime;
-        readHeadSampleTime = static_cast<CARingBuffer::SampleTime>(inOutputTime->mSampleTime - refCon->mInToOutSampleOffset);
-    }
 
-    // Copy the frames from the ring buffer
-    err = refCon->mBuffer.Fetch(outOutputData, framesToOutput, readHeadSampleTime);
-    
-    HandleRingBufferError(err, "OutputDeviceIOProc", "mBuffer.Fetch");
-    
+    // When the input and output devices are set, during start up or because the user changed the
+    // output device, this class (re)allocates the ring buffer (mBuffer). We try to take this
+    // lock before accessing the buffer to make sure it's allocated.
+    //
+    // If we don't get the lock, another thread must be allocating or deallocating it, so we just
+    // give up. We can't avoid audio glitches while changing devices anyway. This class tries to
+    // make sure the IOProcs aren't running when it allocates the buffer, but it can't guarantee
+    // that.
+    //
+    // Note that this is only realtime safe because we only try to lock the mutex. If another
+    // thread has the mutex, it will be a non-realtime thread, so we can't wait for it.
+    CAMutex::Tryer tryer(refCon->mBufferOutputMutex);
+
+    // Disable a warning about accessing mBuffer without holding both mBufferInputMutex and
+    // mBufferOutputMutex. The input IOProc always writes ahead of where the output IOProc will read
+    // in a given IO cycle, so it's safe for them to read and write at the same time.
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wthread-safety"
+    if(tryer.HasLock() && refCon->mBuffer)
+    {
+        // Very occasionally (at least for me) our read head gets ahead of input, i.e. we haven't
+        // received any new input since this IOProc was last called, and we have to recalculate its
+        // position. I figure this might be caused by clock drift but I'm really not sure. It also
+        // happens if the input or output sample times are restarted from zero.
+        //
+        // We also recalculate the offset if the read head is outside of the ring buffer. This
+        // happens for example when you plug in or unplug headphones, which causes the output sample
+        // times to be restarted from zero.
+        //
+        // The vast majority of the time, just using lastInputSampleTime as the read head time
+        // instead of the one we calculate would work fine (and would also account for the above).
+        SInt64 bufferStartTime, bufferEndTime;
+        CARingBufferError err = refCon->mBuffer->GetTimeBounds(bufferStartTime, bufferEndTime);
+        bool outOfBounds = false;
+
+        if(err == kCARingBufferError_OK)
+        {
+            outOfBounds = (readHeadSampleTime < bufferStartTime)
+                    || (readHeadSampleTime - framesToOutput > bufferEndTime);
+        }
+
+        if(lastInputSampleTime < readHeadSampleTime || outOfBounds)
+        {
+            refCon->mRTLogger.LogNoSamplesReady(lastInputSampleTime,
+                                                readHeadSampleTime,
+                                                refCon->mInToOutSampleOffset);
+
+            // Recalculate the in-to-out offset and read head.
+            refCon->mInToOutSampleOffset = inOutputTime->mSampleTime - lastInputSampleTime;
+            readHeadSampleTime = static_cast<CARingBuffer::SampleTime>(
+                    inOutputTime->mSampleTime - refCon->mInToOutSampleOffset);
+        }
+
+        // Copy the frames from the ring buffer.
+        err = refCon->mBuffer->Fetch(outOutputData, framesToOutput, readHeadSampleTime);
+        refCon->mRTLogger.LogIfRingBufferError_Fetch(err);
+
+        if(err != kCARingBufferError_OK)
+        {
+            FillWithSilence(outOutputData);
+        }
+    }
+    else
+    {
+        refCon->mRTLogger.LogRingBufferUnavailable("OutputDeviceIOProc", tryer.HasLock());
+        FillWithSilence(outOutputData);
+    }
+#pragma clang diagnostic pop
+
     refCon->mLastOutputSampleTime = inOutputTime->mSampleTime;
     
     return noErr;
 }
 
 // static
-bool    BGMPlayThrough::UpdateIOProcState(const char* __nullable callerName,
+inline void BGMPlayThrough::FillWithSilence(AudioBufferList* ioBuffer)
+{
+    for(UInt32 i = 0; i < ioBuffer->mNumberBuffers; i++)
+    {
+        memset(ioBuffer->mBuffers[i].mData, 0, ioBuffer->mBuffers[i].mDataByteSize);
+    }
+}
+
+// static
+bool    BGMPlayThrough::UpdateIOProcState(const char* inCallerName,
+                                          BGMPlayThroughRTLogger& inRTLogger,
                                           std::atomic<IOState>& inState,
                                           AudioDeviceIOProcID __nullable inIOProcID,
                                           BGMAudioDevice& inDevice,
@@ -1088,6 +1171,9 @@ bool    BGMPlayThrough::UpdateIOProcState(const char* __nullable callerName,
     //
     // compare_exchange_strong will return true iff it changed inState from Starting to Running.
     // Otherwise it will set prevState to the current value of inState.
+    //
+    // TODO: We probably don't actually need memory_order_seq_cst (the default). Would it be worth
+    //       changing? Might be worth checking for the other atomics/barriers in this class, too.
     IOState prevState = IOState::Starting;
     bool didChangeState = inState.compare_exchange_strong(prevState, IOState::Running);
 
@@ -1105,21 +1191,28 @@ bool    BGMPlayThrough::UpdateIOProcState(const char* __nullable callerName,
         {
             // The IOProc isn't Starting or Running, so it must be Stopping. That is, it's been
             // told to stop itself.
-            
             BGMAssert(outNewState == IOState::Stopping,
                       "BGMPlayThrough::UpdateIOProcState: Unexpected state: %d",
                       outNewState);
             
             bool stoppedSuccessfully = false;
-            BGMLogAndSwallowExceptionsMsg("BGMPlayThrough::UpdateIOProcState", callerName, [&]() {
-                // TODO: If this throws, tell another thread to log the exception rather than
-                //       logging it from a real-time thread.
+
+            try
+            {
                 inDevice.StopIOProc(inIOProcID);
 
                 // StopIOProc didn't throw, so the IOProc won't be called again until the next
                 // time playthrough is started.
                 stoppedSuccessfully = true;
-            });
+            }
+            catch(CAException e)
+            {
+                inRTLogger.LogExceptionStoppingIOProc(inCallerName, e.GetError());
+            }
+            catch(...)
+            {
+                inRTLogger.LogExceptionStoppingIOProc(inCallerName);
+            }
 
             if(stoppedSuccessfully)
             {
@@ -1132,7 +1225,7 @@ bool    BGMPlayThrough::UpdateIOProcState(const char* __nullable callerName,
                 //
                 // Stop won't return until the IOProc has changed inState to Stopped, unless it
                 // times out, so Stop should still be waiting. And since Start and Stop are
-                // mutually exclusive, so this should be safe.
+                // mutually exclusive, this should be safe.
                 //
                 // But if Stop has timed out and inState has changed, we leave it in its new
                 // state (unless there's some ABA problem thing happening), which I suspect is
@@ -1145,8 +1238,8 @@ bool    BGMPlayThrough::UpdateIOProcState(const char* __nullable callerName,
                 }
                 else
                 {
-                    DebugMsg("BGMPlayThrough::UpdateIOProcState: inState changed since last read "
-                             "outNewState = %d", outNewState);
+                    inRTLogger.LogUnexpectedIOStateAfterStopping(inCallerName,
+                                                                 static_cast<int>(outNewState));
                 }
             }
         }
@@ -1155,30 +1248,3 @@ bool    BGMPlayThrough::UpdateIOProcState(const char* __nullable callerName,
     return didChangeState;
 }
 
-// static
-void    BGMPlayThrough::HandleRingBufferError(CARingBufferError inErr,
-                                              const char* inMethodName,
-                                              const char* inCallReturningErr)
-{
-#if DEBUG
-    if(inErr != kCARingBufferError_OK)
-    {
-        const char* errStr = (inErr == kCARingBufferError_TooMuch ? "kCARingBufferError_TooMuch" :
-                              (inErr == kCARingBufferError_CPUOverload ? "kCARingBufferError_CPUOverload" : "unknown error"));
-
-        DebugMsg("BGMPlayThrough::%s: %s returned %s (%d)", inMethodName, inCallReturningErr, errStr, inErr);
-        
-        // kCARingBufferError_CPUOverload wouldn't mean we have a bug, but I think kCARingBufferError_TooMuch would
-        if(inErr != kCARingBufferError_CPUOverload)
-        {
-            Throw(CAException(inErr));
-        }
-    }
-#else
-    // Not sure what we should do to handle these errors in release builds, if anything.
-    // TODO: There's code in Apple's CAPlayThrough.cpp sample code that handles them. (Look for "kCARingBufferError_OK"
-    //       around line 707.) Should be easy enough to use, but it's more complicated that just directly copying it.
-    #pragma unused (inErr, inMethodName, inCallReturningErr)
-#endif
-}
-

BGMApp/BGMApp/BGMPlayThrough.h

@@ -17,7 +17,7 @@
 //  BGMPlayThrough.h
 //  BGMApp
 //
-//  Copyright © 2016, 2017 Kyle Neideck
+//  Copyright © 2016, 2017, 2020 Kyle Neideck
 //
 //  Reads audio from an input device and immediately writes it to an output device. We currently use this class with the input
 //  device always set to BGMDevice and the output device set to the one selected in the preferences menu.
@@ -41,14 +41,17 @@
 
 // Local Includes
 #include "BGMAudioDevice.h"
+#include "BGMPlayThroughRTLogger.h"
 
 // PublicUtility Includes
-#include "CARingBuffer.h"
 #include "CAMutex.h"
+#include "CARingBuffer.h"
+#include "BGMThreadSafetyAnalysis.h"
 
 // STL Includes
 #include <atomic>
 #include <algorithm>
+#include <memory>
 
 // System Includes
 #include <mach/semaphore.h>
@@ -78,7 +81,8 @@ public:
     
 private:
     /*! @throws CAException */
-    void                Init(BGMAudioDevice inInputDevice, BGMAudioDevice inOutputDevice);
+    void                Init(BGMAudioDevice inInputDevice, BGMAudioDevice inOutputDevice)
+                            REQUIRES(mStateMutex);
 
 public:
     /*! @throws CAException */
@@ -87,7 +91,8 @@ public:
     void                Deactivate();
 
 private:
-    void                AllocateBuffer();
+    void                AllocateBuffer() REQUIRES(mStateMutex);
+    void                DeallocateBuffer();
 
     /*! @throws CAException */
     void                CreateIOProcIDs();
@@ -97,7 +102,7 @@ private:
         @return True if both IOProcs are stopped.
         @nonthreadsafe
      */
-    bool                CheckIOProcsAreStopped() const noexcept; // TODO: REQUIRES(mStateMutex);
+    bool                CheckIOProcsAreStopped() const noexcept REQUIRES(mStateMutex);
 	
 public:
     /*!
@@ -115,7 +120,8 @@ public:
     OSStatus            WaitForOutputDeviceToStart() noexcept;
     
 private:
-    void                ReleaseThreadsWaitingForOutputToStart() const;
+    /*! Real-time safe. */
+    void                ReleaseThreadsWaitingForOutputToStart();
     
 public:
     OSStatus            Stop();
@@ -146,7 +152,10 @@ private:
                                            AudioBufferList*        outOutputData,
                                            const AudioTimeStamp*   inOutputTime,
                                            void* __nullable        inClientData);
-    
+
+    /*! Fills the given ABL with zeroes to make it silent. */
+    static inline void  FillWithSilence(AudioBufferList* ioBuffer);
+
     // The state of an IOProc. Used by the IOProc to tell other threads when it's finished starting. Used by other
     // threads to tell the IOProc to stop itself. (Probably used for other things as well.)
     enum class          IOState
@@ -156,27 +165,45 @@ private:
     
     // The IOProcs call this to update their IOState member. Also stops the IOProc if its state has been set to Stopping.
     // Returns true if it changes the state.
-    static bool         UpdateIOProcState(const char* __nullable callerName,
+    static bool         UpdateIOProcState(const char* inCallerName,
+                                          BGMPlayThroughRTLogger& inRTLogger,
                                           std::atomic<IOState>& inState,
                                           AudioDeviceIOProcID __nullable inIOProcID,
                                           BGMAudioDevice& inDevice,
                                           IOState& outNewState);
     
-    static void         HandleRingBufferError(CARingBufferError err,
-                                              const char* methodName,
-                                              const char* callReturningErr);
-    
 private:
-    CARingBuffer        mBuffer;
+    std::unique_ptr<CARingBuffer>    mBuffer PT_GUARDED_BY(mBufferInputMutex)
+                                        PT_GUARDED_BY(mBufferOutputMutex) { nullptr };
     
     AudioDeviceIOProcID __nullable mInputDeviceIOProcID { nullptr };
     AudioDeviceIOProcID __nullable mOutputDeviceIOProcID { nullptr };
     
     BGMAudioDevice      mInputDevice { kAudioObjectUnknown };
     BGMAudioDevice      mOutputDevice { kAudioObjectUnknown };
-    
-    CAMutex             mStateMutex { "Playthrough state" };
-    
+
+    // mStateMutex is the general purpose mutex. mBufferInputMutex and mBufferOutputMutex are
+    // just used to make sure mBuffer, the ring buffer, is allocated when the IOProcs access it. See
+    // the comments in the IOProcs for details.
+    //
+    // If a thread might lock more than one of these mutexes, it *must* take them in this order:
+    //     1. mStateMutex
+    //     2. mBufferInputMutex
+    //     3. mBufferOutputMutex
+    //
+    // The ACQUIRED_BEFORE annotations don't do anything yet. From clang's docs: "ACQUIRED_BEFORE(…)
+    // and ACQUIRED_AFTER(…) are currently unimplemented. To be fixed in a future update." After
+    // they've fixed that, the compiler will enforce the ordering statically.
+    //
+    // TODO: We can't use std::shared_lock because we're still on C++11, but we could use std::lock
+    //       to help ensure the locks are always taken in the right order.
+    // TODO: It would be better to have a separate class for the buffer and its mutexes.
+    CAMutex             mStateMutex ACQUIRED_BEFORE(mBufferInputMutex)
+                            ACQUIRED_BEFORE(mBufferOutputMutex) { "Playthrough state" };
+    CAMutex             mBufferInputMutex ACQUIRED_BEFORE(mBufferOutputMutex)
+                            { "Playthrough ring buffer input" };
+    CAMutex             mBufferOutputMutex { "Playthrough ring buffer output" };
+
     // Signalled when the output IOProc runs. We use it to tell BGMDriver when the output device is ready to receive audio data.
     semaphore_t         mOutputDeviceIOProcSemaphore { SEMAPHORE_NULL };
     
@@ -200,7 +227,9 @@ private:
     
     // Subtract this from the output time to get the input time.
     Float64             mInToOutSampleOffset { 0.0 };
-    
+
+    BGMPlayThroughRTLogger mRTLogger;
+
 };
 
 #pragma clang assume_nonnull end

BGMApp/BGMApp/BGMPlayThroughRTLogger.cpp

@@ -0,0 +1,521 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  BGMPlayThroughRTLogger.cpp
+//  BGMApp
+//
+//  Copyright © 2020 Kyle Neideck
+//
+
+// Self Include
+#include "BGMPlayThroughRTLogger.h"
+
+// Local Includes
+#include "BGM_Utils.h"
+
+// PublicUtility Includes
+#include "CADebugMacros.h"
+
+// STL Includes
+#include <atomic>
+
+// System Includes
+#include <CoreAudio/CoreAudio.h>
+#include <mach/mach_init.h>
+#include <mach/task.h>
+#include <unistd.h>
+
+
+#pragma clang assume_nonnull begin
+
+// Track the number of messages logged when built for the unit tests.
+#if BGM_UnitTest
+    #define LogSync_Debug(inFormat, ...) do { \
+                mNumDebugMessagesLogged++; \
+                DebugMsg(inFormat, ## __VA_ARGS__); \
+            } while (0)
+#else
+    #define LogSync_Debug(inFormat, ...) DebugMsg(inFormat, ## __VA_ARGS__)
+#endif
+
+#pragma mark Construction/Destruction
+
+BGMPlayThroughRTLogger::BGMPlayThroughRTLogger()
+{
+    // Create the semaphore we use to wake up the logging thread when it has messages to log.
+    mWakeUpLoggingThreadSemaphore = CreateSemaphore();
+
+    // Create the logging thread last because it starts immediately and expects the other member
+    // variables to be initialised.
+    mLoggingThread = std::thread(&BGMPlayThroughRTLogger::LoggingThreadEntry, this);
+}
+
+// static
+semaphore_t BGMPlayThroughRTLogger::CreateSemaphore()
+{
+    // TODO: Make a BGMMachSemaphore class to reduce some of this repetitive semaphore code.
+
+    // Create the semaphore.
+    semaphore_t semaphore;
+    kern_return_t error =
+            semaphore_create(mach_task_self(), &semaphore, SYNC_POLICY_FIFO, 0);
+
+    // Check the error code.
+    BGM_Utils::ThrowIfMachError("BGMPlayThroughRTLogger::CreateSemaphore",
+                                "semaphore_create",
+                                error);
+    ThrowIf(semaphore == SEMAPHORE_NULL,
+            CAException(kAudioHardwareUnspecifiedError),
+            "BGMPlayThroughRTLogger::CreateSemaphore: Failed to create semaphore");
+
+    return semaphore;
+}
+
+BGMPlayThroughRTLogger::~BGMPlayThroughRTLogger()
+{
+    // Stop the logging thread.
+    mLoggingThreadShouldExit = true;
+    kern_return_t error = semaphore_signal(mWakeUpLoggingThreadSemaphore);
+
+    BGM_Utils::LogIfMachError("BGMPlayThroughRTLogger::~BGMPlayThroughRTLogger",
+                              "semaphore_signal",
+                              error);
+
+    if(error == KERN_SUCCESS)
+    {
+        // Wait for it to stop.
+        mLoggingThread.join();
+
+        // Destroy the semaphore.
+        error = semaphore_destroy(mach_task_self(), mWakeUpLoggingThreadSemaphore);
+        BGM_Utils::LogIfMachError("BGMPlayThroughRTLogger::~BGMPlayThroughRTLogger",
+                                  "semaphore_destroy",
+                                  error);
+    }
+    else
+    {
+        // If we couldn't tell it to wake up, it's not safe to wait for it to stop or to destroy the
+        // semaphore. We have to detach it so its destructor doesn't cause a crash.
+        mLoggingThread.detach();
+    }
+}
+
+#pragma mark Log Messages
+
+void BGMPlayThroughRTLogger::LogReleasingWaitingThreads()
+{
+    if(!BGMDebugLoggingIsEnabled())
+    {
+        return;
+    }
+
+    if(!mLogReleasingWaitingThreadsMsg.is_lock_free())
+    {
+        // Modifying mLogReleasingWaitingThreadsMsg might cause the thread to lock a mutex that
+        // isn't safe to lock on a realtime thread, so just give up.
+        return;
+    }
+
+    // Set the flag that tells the logging thread to log the message.
+    mLogReleasingWaitingThreadsMsg = true;
+
+    // Wake the logging thread so it can log the message.
+    WakeLoggingThread();
+}
+
+void BGMPlayThroughRTLogger::LogIfMachError_ReleaseWaitingThreadsSignal(mach_error_t inError)
+{
+    if(inError == KERN_SUCCESS)
+    {
+        // No error.
+        return;
+    }
+
+    if(!mReleaseWaitingThreadsSignalError.is_lock_free())
+    {
+        // Modifying mReleaseWaitingThreadsSignalError might cause the thread to lock a mutex that
+        // isn't safe to lock on a realtime thread, so just give up.
+        return;
+    }
+
+    mReleaseWaitingThreadsSignalError = inError;
+    WakeLoggingThread();
+}
+
+void BGMPlayThroughRTLogger::LogIfDroppedFrames(Float64 inFirstInputSampleTime,
+                                                Float64 inLastInputSampleTime)
+{
+    if(inFirstInputSampleTime == inLastInputSampleTime || !BGMDebugLoggingIsEnabled())
+    {
+        // Either we didn't drop any initial frames or we don't need to log a message about it.
+        return;
+    }
+
+    LogAsync(mDroppedFrames, [&]()
+    {
+        // Store the data to include in the log message.
+        mDroppedFrames.firstInputSampleTime = inFirstInputSampleTime;
+        mDroppedFrames.lastInputSampleTime = inLastInputSampleTime;
+    });
+}
+
+void BGMPlayThroughRTLogger::LogNoSamplesReady(CARingBuffer::SampleTime inLastInputSampleTime,
+                                               CARingBuffer::SampleTime inReadHeadSampleTime,
+                                               Float64 inInToOutSampleOffset)
+{
+    if(!BGMDebugLoggingIsEnabled())
+    {
+        return;
+    }
+
+    LogAsync(mNoSamplesReady, [&]()
+    {
+        // Store the data to include in the log message.
+        mNoSamplesReady.lastInputSampleTime = inLastInputSampleTime;
+        mNoSamplesReady.readHeadSampleTime = inReadHeadSampleTime;
+        mNoSamplesReady.inToOutSampleOffset = inInToOutSampleOffset;
+    });
+}
+
+void BGMPlayThroughRTLogger::LogExceptionStoppingIOProc(const char* inCallerName,
+                                                        OSStatus inError,
+                                                        bool inErrorKnown)
+{
+    LogAsync(mExceptionStoppingIOProc, [&]()
+    {
+        // Store the data to include in the log message.
+        mExceptionStoppingIOProc.callerName = inCallerName;
+        mExceptionStoppingIOProc.error = inError;
+        mExceptionStoppingIOProc.errorKnown = inErrorKnown;
+    });
+}
+
+void BGMPlayThroughRTLogger::LogUnexpectedIOStateAfterStopping(const char* inCallerName,
+                                                               int inIOState)
+{
+    LogAsync(mUnexpectedIOStateAfterStopping, [&]()
+    {
+        // Store the data to include in the log message.
+        mUnexpectedIOStateAfterStopping.callerName = inCallerName;
+        mUnexpectedIOStateAfterStopping.ioState = inIOState;
+    });
+}
+
+void BGMPlayThroughRTLogger::LogRingBufferUnavailable(const char* inCallerName, bool inGotLock)
+{
+    LogAsync(mRingBufferUnavailable, [&]()
+    {
+        // Store the data to include in the log message.
+        mRingBufferUnavailable.callerName = inCallerName;
+        mRingBufferUnavailable.gotLock = inGotLock;
+    });
+}
+
+void BGMPlayThroughRTLogger::LogIfRingBufferError(CARingBufferError inError,
+                                                  std::atomic<CARingBufferError>& outError)
+{
+    if(inError == kCARingBufferError_OK)
+    {
+        // No error.
+        return;
+    }
+
+    if(!outError.is_lock_free())
+    {
+        // Modifying outError might cause the thread to lock a mutex that isn't safe to lock on
+        // a realtime thread, so just give up.
+        return;
+    }
+
+    // Store the error.
+    outError = inError;
+
+    // Wake the logging thread so it can log the error.
+    WakeLoggingThread();
+}
+
+template <typename T, typename F>
+void BGMPlayThroughRTLogger::LogAsync(T& inMessageData, F&& inStoreMessageData)
+{
+    if(!inMessageData.shouldLogMessage.is_lock_free())
+    {
+        // Modifying shouldLogMessage might cause the thread to lock a mutex that isn't safe to
+        // lock on a realtime thread, so just give up.
+        return;
+    }
+
+    if(inMessageData.shouldLogMessage)
+    {
+        // The logging thread could be reading inMessageData.
+        return;
+    }
+
+    // Store the data to include in the log message.
+    //
+    // std::forward lets the compiler treat inStoreMessageData as an rvalue if the caller gave it as
+    // an rvalue. No idea if that actually does anything.
+    std::forward<F>(inStoreMessageData)();
+
+    // shouldLogMessage is a std::atomic, so this store also makes sure that the non-atomic stores
+    // in inStoreMessageData will be visible to the logger thread (since the default memory order is
+    // memory_order_seq_cst).
+    inMessageData.shouldLogMessage = true;
+
+    WakeLoggingThread();
+}
+
+void BGMPlayThroughRTLogger::LogSync_Warning(const char* inFormat, ...)
+{
+    va_list args;
+    va_start(args, inFormat);
+
+#if BGM_UnitTest
+    mNumWarningMessagesLogged++;
+#endif
+
+    vLogWarning(inFormat, args);
+
+    va_end(args);
+}
+
+void BGMPlayThroughRTLogger::LogSync_Error(const char* inFormat, ...)
+{
+    va_list args;
+    va_start(args, inFormat);
+
+#if BGM_UnitTest
+    mNumErrorMessagesLogged++;
+
+    if(!mContinueOnErrorLogged)
+    {
+        vLogError(inFormat, args);
+    }
+#else
+    vLogError(inFormat, args);
+#endif
+
+    va_end(args);
+}
+
+#pragma mark Logging Thread
+
+void BGMPlayThroughRTLogger::WakeLoggingThread()
+{
+    kern_return_t error = semaphore_signal(mWakeUpLoggingThreadSemaphore);
+
+    BGMAssert(error == KERN_SUCCESS, "semaphore_signal (%d)", error);
+
+    // We can't do anything useful with the error in release builds. At least, not easily.
+    (void)error;
+}
+
+void BGMPlayThroughRTLogger::LogMessages()
+{
+    // Log the messages/errors from the realtime threads (if any).
+    LogSync_ReleasingWaitingThreads();
+    LogSync_ReleaseWaitingThreadsSignalError();
+    LogSync_DroppedFrames();
+    LogSync_NoSamplesReady();
+    LogSync_ExceptionStoppingIOProc();
+    LogSync_UnexpectedIOStateAfterStopping();
+    LogSync_RingBufferUnavailable();
+    LogSync_RingBufferError(mRingBufferStoreError, "InputDeviceIOProc");
+    LogSync_RingBufferError(mRingBufferFetchError, "OutputDeviceIOProc");
+}
+
+void BGMPlayThroughRTLogger::LogSync_ReleasingWaitingThreads()
+{
+    if(mLogReleasingWaitingThreadsMsg)
+    {
+        LogSync_Debug("BGMPlayThrough::ReleaseThreadsWaitingForOutputToStart: "
+                      "Releasing waiting threads");
+        // Reset it.
+        mLogReleasingWaitingThreadsMsg = false;
+    }
+}
+
+void BGMPlayThroughRTLogger::LogSync_ReleaseWaitingThreadsSignalError()
+{
+    if(mReleaseWaitingThreadsSignalError != KERN_SUCCESS)
+    {
+        BGM_Utils::LogIfMachError("BGMPlayThrough::ReleaseThreadsWaitingForOutputToStart",
+                                  "semaphore_signal_all",
+                                  mReleaseWaitingThreadsSignalError);
+        // Reset it.
+        mReleaseWaitingThreadsSignalError = KERN_SUCCESS;
+    }
+}
+
+void BGMPlayThroughRTLogger::LogSync_DroppedFrames()
+{
+    if(mDroppedFrames.shouldLogMessage)
+    {
+        LogSync_Debug("BGMPlayThrough::OutputDeviceIOProc: "
+                      "Dropped %f frames before output started. %s%f %s%f",
+                      (mDroppedFrames.lastInputSampleTime - mDroppedFrames.firstInputSampleTime),
+                      "mFirstInputSampleTime=",
+                      mDroppedFrames.firstInputSampleTime,
+                      "mLastInputSampleTime=",
+                      mDroppedFrames.lastInputSampleTime);
+        mDroppedFrames.shouldLogMessage = false;
+    }
+}
+
+void BGMPlayThroughRTLogger::LogSync_NoSamplesReady()
+{
+    if(mNoSamplesReady.shouldLogMessage)
+    {
+        LogSync_Debug("BGMPlayThrough::OutputDeviceIOProc: "
+                      "No input samples ready at output sample time. %s%lld %s%lld %s%f",
+                      "lastInputSampleTime=", mNoSamplesReady.lastInputSampleTime,
+                      "readHeadSampleTime=", mNoSamplesReady.readHeadSampleTime,
+                      "mInToOutSampleOffset=", mNoSamplesReady.inToOutSampleOffset);
+        mNoSamplesReady.shouldLogMessage = false;
+    }
+}
+
+void BGMPlayThroughRTLogger::LogSync_ExceptionStoppingIOProc()
+{
+    if(mExceptionStoppingIOProc.shouldLogMessage)
+    {
+        const char error4CC[5] = CA4CCToCString(mExceptionStoppingIOProc.error);
+        LogSync_Error("BGMPlayThrough::UpdateIOProcState: "
+                      "Exception while stopping IOProc %s: %s (%d)",
+                      mExceptionStoppingIOProc.callerName,
+                      mExceptionStoppingIOProc.errorKnown ? error4CC : "unknown",
+                      mExceptionStoppingIOProc.error);
+        mExceptionStoppingIOProc.shouldLogMessage = false;
+    }
+}
+
+void BGMPlayThroughRTLogger::LogSync_UnexpectedIOStateAfterStopping()
+{
+    if(mUnexpectedIOStateAfterStopping.shouldLogMessage)
+    {
+        LogSync_Warning("BGMPlayThrough::UpdateIOProcState: "
+                        "%s IO state changed since last read. state = %d",
+                        mUnexpectedIOStateAfterStopping.callerName,
+                        mUnexpectedIOStateAfterStopping.ioState);
+        mUnexpectedIOStateAfterStopping.shouldLogMessage = false;
+    }
+}
+
+void BGMPlayThroughRTLogger::LogSync_RingBufferUnavailable()
+{
+    if(mRingBufferUnavailable.shouldLogMessage)
+    {
+        LogSync_Warning("BGMPlayThrough::%s: Ring buffer unavailable. %s",
+                        mRingBufferUnavailable.callerName,
+                        mRingBufferUnavailable.gotLock ?
+                            "No buffer currently allocated." :
+                            "Buffer locked for allocation/deallocation by another thread.");
+        mRingBufferUnavailable.shouldLogMessage = false;
+    }
+}
+
+void BGMPlayThroughRTLogger::LogSync_RingBufferError(
+        std::atomic<CARingBufferError>& ioRingBufferError,
+        const char* inMethodName)
+{
+    CARingBufferError error = ioRingBufferError;
+
+    switch(error)
+    {
+        case kCARingBufferError_OK:
+            // No error.
+            return;
+        case kCARingBufferError_CPUOverload:
+            // kCARingBufferError_CPUOverload might not be our fault, so just log a warning.
+            LogSync_Warning("BGMPlayThrough::%s: Ring buffer error: "
+                            "kCARingBufferError_CPUOverload (%d)",
+                            inMethodName,
+                            error);
+            break;
+        default:
+            // Other types of CARingBuffer errors should never occur. This will crash debug builds.
+            LogSync_Error("BGMPlayThrough::%s: Ring buffer error: %s (%d)",
+                          inMethodName,
+                          (error == kCARingBufferError_TooMuch ?
+                                  "kCARingBufferError_TooMuch" :
+                                  "unknown error"),
+                          error);
+            break;
+    };
+
+    // Reset it.
+    ioRingBufferError = kCARingBufferError_OK;
+}
+
+// static
+void* __nullable BGMPlayThroughRTLogger::LoggingThreadEntry(BGMPlayThroughRTLogger* inRefCon)
+{
+    DebugMsg("BGMPlayThroughRTLogger::IOProcLoggingThreadEntry: "
+             "Starting the IOProc logging thread");
+
+    while(!inRefCon->mLoggingThreadShouldExit)
+    {
+        // Log the messages, if there are any to log.
+        inRefCon->LogMessages();
+
+        // Wait until woken up.
+        kern_return_t error = semaphore_wait(inRefCon->mWakeUpLoggingThreadSemaphore);
+        BGM_Utils::LogIfMachError("BGMPlayThroughRTLogger::IOProcLoggingThreadEntry",
+                                  "semaphore_wait",
+                                  error);
+    }
+
+    DebugMsg("BGMPlayThroughRTLogger::IOProcLoggingThreadEntry: IOProc logging thread exiting");
+
+    return nullptr;
+}
+
+#if BGM_UnitTest
+
+#pragma mark Test Helpers
+
+bool BGMPlayThroughRTLogger::WaitUntilLoggerThreadIdle()
+{
+    int msWaited = 0;
+
+    while(mLogReleasingWaitingThreadsMsg ||
+            mReleaseWaitingThreadsSignalError != KERN_SUCCESS ||
+            mDroppedFrames.shouldLogMessage ||
+            mNoSamplesReady.shouldLogMessage ||
+            mUnexpectedIOStateAfterStopping.shouldLogMessage ||
+            mRingBufferUnavailable.shouldLogMessage ||
+            mExceptionStoppingIOProc.shouldLogMessage ||
+            mRingBufferStoreError != kCARingBufferError_OK ||
+            mRingBufferFetchError != kCARingBufferError_OK)
+    {
+        // Poll until the logger thread has nothing left to log. (Ideally we'd use a semaphore
+        // instead of polling, but it isn't worth the effort at this point.)
+        usleep(10 * 1000);
+        msWaited += 10;
+
+        // Time out after 5 seconds.
+        if(msWaited > 5000)
+        {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+#endif /* BGM_UnitTest */
+
+#pragma clang assume_nonnull end
+

BGMApp/BGMApp/BGMPlayThroughRTLogger.h

@@ -0,0 +1,227 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  BGMPlayThroughRTLogger.h
+//  BGMApp
+//
+//  Copyright © 2020 Kyle Neideck
+//
+//  A real-time safe logger for BGMPlayThrough. The messages are logged asynchronously by a
+//  non-realtime thread.
+//
+//  For the sake of simplicity, this class is very closely coupled with BGMPlayThrough and its
+//  methods make assumptions about where they will be called. Also, if the same logging method is
+//  called multiple times before the logging thread next checks for messages, it will only log the
+//  message for one of those calls and ignore the others.
+//
+//  This class's methods are real-time safe in that they return in a bounded amount of time and we
+//  think they're probably fast enough that the callers won't miss their deadlines, but we don't try
+//  to guarantee it. Some of them should only be called in unusual cases where it's worth increasing
+//  the risk of a thread missing its deadline.
+//
+
+#ifndef BGMApp__BGMPlayThroughRTLogger
+#define BGMApp__BGMPlayThroughRTLogger
+
+// PublicUtility Includes
+#include "CARingBuffer.h"
+
+// STL Includes
+#include <thread>
+
+// System Includes
+#include <mach/error.h>
+#include <mach/semaphore.h>
+
+
+#pragma clang assume_nonnull begin
+
+class BGMPlayThroughRTLogger
+{
+
+#pragma mark Construction/Destruction
+
+public:
+                            BGMPlayThroughRTLogger();
+                            ~BGMPlayThroughRTLogger();
+                            BGMPlayThroughRTLogger(const BGMPlayThroughRTLogger&) = delete;
+                            BGMPlayThroughRTLogger& operator=(
+                                    const BGMPlayThroughRTLogger&) = delete;
+private:
+    static semaphore_t      CreateSemaphore();
+
+#pragma mark Log Messages
+
+public:
+    /*! For BGMPlayThrough::ReleaseThreadsWaitingForOutputToStart. */
+    void                    LogReleasingWaitingThreads();
+    /*! For BGMPlayThrough::ReleaseThreadsWaitingForOutputToStart. */
+    void                    LogIfMachError_ReleaseWaitingThreadsSignal(mach_error_t inError);
+
+    /*! For BGMPlayThrough::OutputDeviceIOProc. Not thread-safe. */
+    void                    LogIfDroppedFrames(Float64 inFirstInputSampleTime,
+                                               Float64 inLastInputSampleTime);
+    /*! For BGMPlayThrough::OutputDeviceIOProc. Not thread-safe. */
+    void                    LogNoSamplesReady(CARingBuffer::SampleTime inLastInputSampleTime,
+                                              CARingBuffer::SampleTime inReadHeadSampleTime,
+                                              Float64 inInToOutSampleOffset);
+
+    /*! For BGMPlayThrough::UpdateIOProcState. Not thread-safe. */
+    void                    LogExceptionStoppingIOProc(const char* inCallerName)
+                            {
+                                LogExceptionStoppingIOProc(inCallerName, noErr, false);
+                            }
+    /*! For BGMPlayThrough::UpdateIOProcState. Not thread-safe. */
+    void                    LogExceptionStoppingIOProc(const char* inCallerName, OSStatus inError)
+                            {
+                                LogExceptionStoppingIOProc(inCallerName, inError, true);
+                            }
+
+private:
+    void                    LogExceptionStoppingIOProc(const char* inCallerName,
+                                                       OSStatus inError,
+                                                       bool inErrorKnown);
+
+public:
+    /*! For BGMPlayThrough::UpdateIOProcState. Not thread-safe. */
+    void                    LogUnexpectedIOStateAfterStopping(const char* inCallerName,
+                                                              int inIOState);
+    /*! For BGMPlayThrough::InputDeviceIOProc and BGMPlayThrough::OutputDeviceIOProc. */
+    void                    LogRingBufferUnavailable(const char* inCallerName, bool inGotLock);
+    /*! For BGMPlayThrough::OutputDeviceIOProc. */
+    void                    LogIfRingBufferError_Fetch(CARingBufferError inError)
+                            {
+                                LogIfRingBufferError(inError, mRingBufferFetchError);
+                            }
+    /*! For BGMPlayThrough::InputDeviceIOProc. */
+    void                    LogIfRingBufferError_Store(CARingBufferError inError)
+                            {
+                                LogIfRingBufferError(inError, mRingBufferStoreError);
+                            }
+
+private:
+    void                    LogIfRingBufferError(CARingBufferError inError,
+                                                 std::atomic<CARingBufferError>& outError);
+
+    template <typename T, typename F>
+    void                    LogAsync(T& inMessageData, F&& inStoreMessageData);
+
+    // Wrapper methods used to mock out the logging for unit tests.
+    void                    LogSync_Warning(const char* inFormat, ...) __printflike(2, 3);
+    void                    LogSync_Error(const char* inFormat, ...) __printflike(2, 3);
+
+#pragma mark Logging Thread
+
+private:
+    void                    WakeLoggingThread();
+
+    void                    LogMessages();
+    void                    LogSync_ReleasingWaitingThreads();
+    void                    LogSync_ReleaseWaitingThreadsSignalError();
+    void                    LogSync_DroppedFrames();
+    void                    LogSync_NoSamplesReady();
+    void                    LogSync_ExceptionStoppingIOProc();
+    void                    LogSync_UnexpectedIOStateAfterStopping();
+    void                    LogSync_RingBufferUnavailable();
+    void                    LogSync_RingBufferError(
+                                std::atomic<CARingBufferError>& ioRingBufferError,
+                                const char* inMethodName);
+
+    // The entry point of the logging thread (mLoggingThread).
+    static void* __nullable LoggingThreadEntry(BGMPlayThroughRTLogger* inRefCon);
+
+#if BGM_UnitTest
+
+#pragma mark Test Helpers
+
+public:
+    /*!
+     * @return True if the logger thread finished logging the requested messages. False if it still
+     *         had messages to log after 5 seconds.
+     */
+    bool                    WaitUntilLoggerThreadIdle();
+
+#endif /* BGM_UnitTest */
+
+private:
+    // For BGMPlayThrough::ReleaseThreadsWaitingForOutputToStart
+    std::atomic<bool>       mLogReleasingWaitingThreadsMsg { false };
+    std::atomic<kern_return_t> mReleaseWaitingThreadsSignalError { KERN_SUCCESS };
+
+    // For BGMPlayThrough::InputDeviceIOProc and BGMPlayThrough::OutputDeviceIOProc
+    struct {
+        Float64 firstInputSampleTime;
+        Float64 lastInputSampleTime;
+        std::atomic<bool> shouldLogMessage { false };
+    } mDroppedFrames;
+
+    struct {
+        CARingBuffer::SampleTime lastInputSampleTime;
+        CARingBuffer::SampleTime readHeadSampleTime;
+        Float64 inToOutSampleOffset;
+        std::atomic<bool> shouldLogMessage { false };
+    } mNoSamplesReady;
+
+    struct {
+        const char* callerName;
+        bool gotLock;
+        std::atomic<bool> shouldLogMessage { false };
+    } mRingBufferUnavailable;
+
+    // For BGMPlayThrough::UpdateIOProcState
+    struct {
+        const char* callerName;
+        int ioState;
+        std::atomic<bool> shouldLogMessage { false };
+    } mUnexpectedIOStateAfterStopping;
+
+    struct {
+        const char* callerName;
+        OSStatus error;
+        bool errorKnown;  // If false, we didn't get an error code from the exception.
+        std::atomic<bool> shouldLogMessage { false };
+    } mExceptionStoppingIOProc;
+
+    // For BGMPlayThrough::OutputDeviceIOProc
+    std::atomic<CARingBufferError> mRingBufferStoreError { kCARingBufferError_OK };
+    // For BGMPlayThrough::InputDeviceIOProc.
+    std::atomic<CARingBufferError> mRingBufferFetchError { kCARingBufferError_OK };
+
+    // Signalled to wake up the mLoggingThread when it has messages to log.
+    semaphore_t             mWakeUpLoggingThreadSemaphore;
+    std::atomic<bool>       mLoggingThreadShouldExit { false };
+    // The thread that actually logs the messages.
+    std::thread             mLoggingThread;
+
+#if BGM_UnitTest
+
+public:
+    // Tests normally crash (abort) if LogError is called. This flag lets us test the code that
+    // would otherwise call LogError.
+    bool                    mContinueOnErrorLogged { false };
+
+    int                     mNumDebugMessagesLogged { 0 };
+    int                     mNumWarningMessagesLogged { 0 };
+    int                     mNumErrorMessagesLogged { 0 };
+
+#endif /* BGM_UnitTest */
+
+};
+
+#pragma clang assume_nonnull end
+
+#endif /* BGMApp__BGMPlayThroughRTLogger */
+

BGMApp/BGMApp/BGMPreferredOutputDevices.mm

@@ -113,7 +113,7 @@ NSString* const kAudioSystemSettingsPlist =
     // BGMApp's stored preferred devices to fill in the rest optimistically. This doesn't help us
     // tell when to switch to a newly connected device, but it should improve our chances of
     // switching to the best device if the current output device is disconnected.
-    NSArray<NSDictionary*>* preferredOutputDeviceInfos = @[];
+    NSArray<NSDictionary*>* _Nonnull preferredOutputDeviceInfos = @[];
 
     // If we can't read the Plist, we only know that the current systemwide default device is the
     // most-preferred device that's currently connected.

BGMApp/BGMApp/BGMStatusBarItem.h

@@ -17,7 +17,7 @@
 //  BGMStatusBarItem.h
 //  BGMApp
 //
-//  Copyright © 2019 Kyle Neideck
+//  Copyright © 2019, 2020 Kyle Neideck
 //
 //  The button in the system status bar (the bar with volume, battery, clock, etc.) to show the main
 //  menu for the app. These are called "menu bar extras" in the Human Interface Guidelines.
@@ -25,6 +25,7 @@
 
 // Local Includes
 #import "BGMAudioDeviceManager.h"
+#import "BGMDebugLoggingMenuItem.h"
 
 // System Includes
 #import <Cocoa/Cocoa.h>
@@ -57,6 +58,10 @@ static BGMStatusBarIcon const kBGMStatusBarIconDefaultValue = BGMFermataStatusBa
 // same as the icon for the macOS volume status bar item.
 @property BGMStatusBarIcon icon;
 
+// If the user holds down the option key when they click the status bar icon, this menu item will be
+// shown in the main menu.
+- (void) setDebugLoggingMenuItem:(BGMDebugLoggingMenuItem*)menuItem;
+
 @end
 
 #pragma clang assume_nonnull end

BGMApp/BGMApp/BGMStatusBarItem.mm

@@ -17,7 +17,7 @@
 //  BGMStatusBarItem.m
 //  BGMApp
 //
-//  Copyright © 2019 Kyle Neideck
+//  Copyright © 2019, 2020 Kyle Neideck
 //
 
 // Self Include
@@ -48,11 +48,16 @@ static CGFloat const kVolumeIconAdditionalVerticalPadding = 0.075;
     NSImage* volumeIcon3SoundWaves;
 
     NSStatusItem* statusBarItem;
+    BGMDebugLoggingMenuItem* debugLoggingMenuItem;
+
     BGMVolumeChangeListener* volumeChangeListener;
+    id __nullable clickEventHandler;
 
     BGMStatusBarIcon _icon;
 }
 
+#pragma mark Initialisation
+
 - (instancetype) initWithMenu:(NSMenu*)bgmMenu
                  audioDevices:(BGMAudioDeviceManager*)devices
                  userDefaults:(BGMUserDefaults*)defaults {
@@ -72,6 +77,10 @@ static CGFloat const kVolumeIconAdditionalVerticalPadding = 0.075;
         // Set the menu item to open the main menu.
         statusBarItem.menu = bgmMenu;
 
+        // Monitor click events so we can show extra options in the menu if the user was holding the
+        // option key.
+        clickEventHandler = [self addClickMonitor];
+
         // Set the accessibility label to "Background Music". (We intentionally don't set a title or
         // a tooltip.)
         if ([BGMStatusBarItem buttonAvailable]) {
@@ -92,17 +101,41 @@ static CGFloat const kVolumeIconAdditionalVerticalPadding = 0.075;
     return self;
 }
 
+- (id __nullable) addClickMonitor {
+    NSEvent* __nullable (^handlerBlock)(NSEvent*) =
+        ^NSEvent* __nullable (NSEvent* event) {
+            [self statusBarItemWasClicked:event];
+            return event;
+        };
+
+    // TODO: I doubt this works well with VoiceOver.
+    return [NSEvent addLocalMonitorForEventsMatchingMask:NSEventMaskLeftMouseDown
+                                                 handler:handlerBlock];
+}
+
 - (void) dealloc {
     delete volumeChangeListener;
+
+    if (clickEventHandler) {
+        [NSEvent removeMonitor:(id)clickEventHandler];
+        clickEventHandler = nil;
+    }
 }
 
 - (void) initIcons {
     // Load the icons.
     fermataIcon = [NSImage imageNamed:@"FermataIcon"];
-    volumeIcon0SoundWaves = [NSImage imageNamed:@"Volume0"];
-    volumeIcon1SoundWave = [NSImage imageNamed:@"Volume1"];
-    volumeIcon2SoundWaves = [NSImage imageNamed:@"Volume2"];
-    volumeIcon3SoundWaves = [NSImage imageNamed:@"Volume3"];
+    if (@available(macOS 11.0, *)) {
+        volumeIcon0SoundWaves = [NSImage imageWithSystemSymbolName:@"speaker.fill" accessibilityDescription:nil];
+        volumeIcon1SoundWave = [NSImage imageWithSystemSymbolName:@"speaker.wave.1.fill" accessibilityDescription:nil];
+        volumeIcon2SoundWaves = [NSImage imageWithSystemSymbolName:@"speaker.wave.2.fill" accessibilityDescription:nil];
+        volumeIcon3SoundWaves = [NSImage imageWithSystemSymbolName:@"speaker.wave.3.fill" accessibilityDescription:nil];
+    } else {
+        volumeIcon0SoundWaves = [NSImage imageNamed:@"Volume0"];
+        volumeIcon1SoundWave = [NSImage imageNamed:@"Volume1"];
+        volumeIcon2SoundWaves = [NSImage imageNamed:@"Volume2"];
+        volumeIcon3SoundWaves = [NSImage imageNamed:@"Volume3"];
+    }
 
     // Set the icons' sizes.
     NSRect statusBarItemFrame;
@@ -142,6 +175,8 @@ static CGFloat const kVolumeIconAdditionalVerticalPadding = 0.075;
     [volumeIcon3SoundWaves setTemplate:YES];
 }
 
+#pragma mark Accessors
+
 + (BOOL) buttonAvailable {
     // NSStatusItem doesn't have the "button" property on OS X 10.9.
     return (floor(NSAppKitVersionNumber) >= NSAppKitVersionNumber10_10);
@@ -188,6 +223,8 @@ static CGFloat const kVolumeIconAdditionalVerticalPadding = 0.075;
     });
 }
 
+#pragma mark Volume Icon
+
 - (void) bgmDeviceVolumeDidChange {
     if (self.icon == BGMVolumeStatusBarIcon) {
         [self updateVolumeStatusBarIcon];
@@ -251,6 +288,21 @@ static CGFloat const kVolumeIconAdditionalVerticalPadding = 0.075;
              statusBarItem.image.name.UTF8String);
 }
 
+#pragma mark Debug Logging Menu Item
+
+- (void) statusBarItemWasClicked:(NSEvent* __nonnull)event {
+    if ((event.modifierFlags & NSEventModifierFlagOption) != 0) {
+        DebugMsg("BGMStatusBarItem::statusBarItemWasClicked: Option key held");
+        [debugLoggingMenuItem setMenuShowingExtraOptions:YES];
+    } else {
+        [debugLoggingMenuItem setMenuShowingExtraOptions:NO];
+    }
+}
+
+- (void) setDebugLoggingMenuItem:(BGMDebugLoggingMenuItem*)menuItem {
+    debugLoggingMenuItem = menuItem;
+}
+
 @end
 
 #pragma clang assume_nonnull end

BGMApp/BGMApp/BGMTermination.h

@@ -19,7 +19,7 @@
 //
 //  Copyright © 2017 Kyle Neideck
 //
-//  Cleans up if BGMApp crashes because of an uncaught C++ or Objective C exception, or is sent
+//  Cleans up if BGMApp crashes because of an uncaught C++ or Objective-C exception, or is sent
 //  SIGINT/SIGTERM/SIGQUIT. Currently, it just changes the default output device from BGMDevice to
 //  the real output device and records debug info for some types of crashes.
 //

BGMApp/BGMApp/BGMTermination.mm

@@ -83,7 +83,7 @@ void BGMTermination::SetUpTerminationCleanUp(BGMAudioDeviceManager* inAudioDevic
     StartExitSignalsThread();
 
     // Wrap the default handler for std::terminate, which is called if BGMApp crashes because of an
-    // uncaught C++ or Objective C exception, so we can clean up first.
+    // uncaught C++ or Objective-C exception, so we can clean up first.
     sOriginalTerminateHandler = std::get_terminate();
 
     std::set_terminate([] {

BGMApp/BGMApp/Base.lproj/MainMenu.xib

@@ -1,9 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="14835.7" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
+<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="22505" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
     <dependencies>
         <deployment identifier="macosx"/>
-        <development version="8000" identifier="xcode"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="14835.7"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="22505"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <objects>
@@ -21,6 +20,7 @@
                 <outlet property="appVolumeView" destination="MWB-XH-kFI" id="eFA-RN-VMC"/>
                 <outlet property="autoPauseMenuItemUnwrapped" destination="nHv-T8-1nb" id="Lie-Cx-jw6"/>
                 <outlet property="bgmMenu" destination="8AN-nh-rEe" id="UWn-BX-eLy"/>
+                <outlet property="debugLoggingMenuItemUnwrapped" destination="sc9-vO-KyP" id="Zyd-0v-0RN"/>
                 <outlet property="outputVolumeLabel" destination="wfC-C6-SLv" id="Nuf-mo-osG"/>
                 <outlet property="outputVolumeSlider" destination="9Ru-Sc-dqC" id="wv0-Md-BwF"/>
                 <outlet property="outputVolumeView" destination="JOz-H1-mj9" id="xeJ-fk-NMI"/>
@@ -58,7 +58,7 @@
                             <menuItem title="Background Music Logo" state="on" tag="2" id="9VF-qy-6fh">
                                 <modifierMask key="keyEquivalentModifierMask"/>
                             </menuItem>
-                            <menuItem title="Volume Icon" tag="3" toolTip="todo" id="B47-O2-wd0">
+                            <menuItem title="Volume Icon" tag="3" id="B47-O2-wd0">
                                 <modifierMask key="keyEquivalentModifierMask"/>
                             </menuItem>
                             <menuItem isSeparatorItem="YES" id="pYP-Fy-nKA"/>
@@ -68,6 +68,9 @@
                         </items>
                     </menu>
                 </menuItem>
+                <menuItem title="Debug Logging" hidden="YES" toolTip="Log detailed messages to help diagnose bugs. Search for &quot;bgm&quot; or &quot;background music&quot; in Console.app." id="sc9-vO-KyP">
+                    <modifierMask key="keyEquivalentModifierMask"/>
+                </menuItem>
                 <menuItem title="Quit Background Music" id="Nj2-gJ-DhW">
                     <modifierMask key="keyEquivalentModifierMask"/>
                     <connections>
@@ -82,7 +85,7 @@
             <rect key="frame" x="0.0" y="0.0" width="269" height="47"/>
             <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
             <subviews>
-                <textField identifier="AppName" horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" allowsCharacterPickerTouchBarItem="YES" translatesAutoresizingMaskIntoConstraints="NO" id="Xmd-bg-huG" customClass="BGMAVM_AppNameLabel">
+                <textField identifier="AppName" focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" allowsCharacterPickerTouchBarItem="YES" translatesAutoresizingMaskIntoConstraints="NO" id="Xmd-bg-huG" customClass="BGMAVM_AppNameLabel">
                     <rect key="frame" x="42" y="28" width="115" height="14"/>
                     <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                     <textFieldCell key="cell" controlSize="small" lineBreakMode="truncatingTail" allowsUndo="NO" sendsActionOnEndEditing="YES" alignment="left" title="App name here" usesSingleLineMode="YES" id="ZHF-ZW-Oqg">
@@ -99,7 +102,7 @@
                 <slider verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="I1l-Ci-4md" customClass="BGMAVM_VolumeSlider">
                     <rect key="frame" x="163" y="27" width="74" height="15"/>
                     <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
-                    <sliderCell key="cell" controlSize="small" continuous="YES" state="on" alignment="left" maxValue="100" doubleValue="50" tickMarkPosition="above" sliderType="linear" id="Jmg-df-9Xl"/>
+                    <sliderCell key="cell" controlSize="mini" continuous="YES" state="on" alignment="left" maxValue="100" doubleValue="50" tickMarkPosition="above" sliderType="linear" id="Jmg-df-9Xl"/>
                     <accessibility description="Volume"/>
                 </slider>
                 <slider toolTip="Pan" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="2mh-uO-kOV" customClass="BGMAVM_PanSlider">
@@ -108,7 +111,7 @@
                     <sliderCell key="cell" controlSize="mini" continuous="YES" state="on" alignment="left" minValue="-100" maxValue="100" tickMarkPosition="below" numberOfTickMarks="1" sliderType="linear" id="ccM-Mt-93g"/>
                     <accessibility description="Pan"/>
                 </slider>
-                <button verticalHuggingPriority="750" fixedFrame="YES" tag="1" springLoaded="YES" translatesAutoresizingMaskIntoConstraints="NO" id="vTG-n6-GxY" customClass="BGMAVM_ShowMoreControlsButton">
+                <button tag="1" springLoaded="YES" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="vTG-n6-GxY" customClass="BGMAVM_ShowMoreControlsButton">
                     <rect key="frame" x="243" y="27" width="16" height="17"/>
                     <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                     <contentFilters>
@@ -124,20 +127,20 @@
                         <font key="font" metaFont="system"/>
                     </buttonCell>
                 </button>
-                <textField identifier="PanLeft" toolTip="Pan" horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="9jc-9i-jw2">
+                <textField identifier="PanLeft" toolTip="Pan" focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="9jc-9i-jw2">
                     <rect key="frame" x="162" y="-1" width="12" height="17"/>
                     <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                     <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="L" id="hgE-7A-bez">
-                        <font key="font" metaFont="miniSystem"/>
+                        <font key="font" metaFont="menu" size="9"/>
                         <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
                         <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                     </textFieldCell>
                 </textField>
-                <textField identifier="PanRight" toolTip="Pan" horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="1lZ-hX-6Kl">
+                <textField identifier="PanRight" toolTip="Pan" focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="1lZ-hX-6Kl">
                     <rect key="frame" x="228" y="-1" width="12" height="17"/>
                     <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                     <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="R" id="lzr-NO-0Na">
-                        <font key="font" metaFont="miniSystem"/>
+                        <font key="font" metaFont="menu" size="9"/>
                         <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
                         <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                     </textFieldCell>
@@ -145,16 +148,16 @@
             </subviews>
             <point key="canvasLocation" x="117" y="-45"/>
         </customView>
-        <window allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" restorable="NO" hidesOnDeactivate="YES" visibleAtLaunch="NO" animationBehavior="default" id="Cf4-3V-gl1" customClass="NSPanel">
-            <windowStyleMask key="styleMask" titled="YES" closable="YES" utility="YES"/>
+        <window allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" restorable="NO" hidesOnDeactivate="YES" releasedWhenClosed="NO" visibleAtLaunch="NO" animationBehavior="default" id="Cf4-3V-gl1" customClass="NSPanel">
+            <windowStyleMask key="styleMask" titled="YES" closable="YES" utility="YES" nonactivatingPanel="YES"/>
             <windowPositionMask key="initialPositionMask" topStrut="YES"/>
             <rect key="contentRect" x="248" y="350" width="1002" height="335"/>
-            <rect key="screenRect" x="0.0" y="0.0" width="1440" height="877"/>
+            <rect key="screenRect" x="0.0" y="0.0" width="1512" height="920"/>
             <view key="contentView" id="HlB-hX-Y0Y">
                 <rect key="frame" x="0.0" y="0.0" width="1002" height="335"/>
                 <autoresizingMask key="autoresizingMask"/>
                 <subviews>
-                    <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" allowsCharacterPickerTouchBarItem="YES" translatesAutoresizingMaskIntoConstraints="NO" id="r51-dd-LGP">
+                    <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" allowsCharacterPickerTouchBarItem="YES" translatesAutoresizingMaskIntoConstraints="NO" id="r51-dd-LGP">
                         <rect key="frame" x="71" y="125" width="240" height="22"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                         <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" alignment="center" title="Background Music" id="Dw2-nu-eBQ">
@@ -163,16 +166,16 @@
                             <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                         </textFieldCell>
                     </textField>
-                    <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" tag="1" allowsCharacterPickerTouchBarItem="YES" translatesAutoresizingMaskIntoConstraints="NO" id="ekc-h0-I43">
+                    <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" tag="1" allowsCharacterPickerTouchBarItem="YES" translatesAutoresizingMaskIntoConstraints="NO" id="ekc-h0-I43">
                         <rect key="frame" x="71" y="100" width="240" height="17"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
-                        <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" alignment="center" title="Version 0.3.1" id="FDH-7l-wFf">
+                        <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" alignment="center" title="Version 0.4.3" id="FDH-7l-wFf">
                             <font key="font" metaFont="system"/>
                             <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
                             <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                         </textFieldCell>
                     </textField>
-                    <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" allowsCharacterPickerTouchBarItem="YES" translatesAutoresizingMaskIntoConstraints="NO" id="L5P-Lw-aCd">
+                    <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" allowsCharacterPickerTouchBarItem="YES" translatesAutoresizingMaskIntoConstraints="NO" id="L5P-Lw-aCd">
                         <rect key="frame" x="413" y="298" width="270" height="17"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                         <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" alignment="left" title="Licensed under GPL v2 or any later version." id="ETh-En-bzX">
@@ -185,7 +188,7 @@
                         <rect key="frame" x="383" y="93" width="5" height="150"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                     </box>
-                    <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" tag="3" allowsCharacterPickerTouchBarItem="YES" translatesAutoresizingMaskIntoConstraints="NO" id="nx6-kQ-N8Z" customClass="BGMLinkField">
+                    <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" tag="3" allowsCharacterPickerTouchBarItem="YES" translatesAutoresizingMaskIntoConstraints="NO" id="nx6-kQ-N8Z" customClass="BGMLinkField">
                         <rect key="frame" x="36" y="50" width="310" height="17"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                         <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" alignment="center" tag="3" title="https://github.com/kyleneideck/BackgroundMusic" placeholderString="" id="VOb-5X-o3R">
@@ -213,11 +216,11 @@
                     <scrollView fixedFrame="YES" horizontalLineScroll="10" horizontalPageScroll="10" verticalLineScroll="10" verticalPageScroll="10" hasHorizontalScroller="NO" usesPredominantAxisScrolling="NO" translatesAutoresizingMaskIntoConstraints="NO" id="eqz-ap-PAC">
                         <rect key="frame" x="415" y="45" width="567" height="245"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
-                        <clipView key="contentView" ambiguous="YES" drawsBackground="NO" id="Cdb-RA-YK0">
+                        <clipView key="contentView" drawsBackground="NO" id="Cdb-RA-YK0">
                             <rect key="frame" x="1" y="1" width="565" height="243"/>
                             <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                             <subviews>
-                                <textView ambiguous="YES" editable="NO" importsGraphics="NO" richText="NO" verticallyResizable="YES" id="LSG-PF-cl8">
+                                <textView editable="NO" importsGraphics="NO" richText="NO" verticallyResizable="YES" id="LSG-PF-cl8">
                                     <rect key="frame" x="-6" y="0.0" width="577" height="243"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                     <color key="textColor" name="textColor" catalog="System" colorSpace="catalog"/>
@@ -240,29 +243,38 @@
                             <autoresizingMask key="autoresizingMask"/>
                         </scroller>
                     </scrollView>
-                    <textField verticalHuggingPriority="750" horizontalCompressionResistancePriority="250" fixedFrame="YES" allowsCharacterPickerTouchBarItem="YES" translatesAutoresizingMaskIntoConstraints="NO" id="6qu-yI-r00">
+                    <textField focusRingType="none" verticalHuggingPriority="750" horizontalCompressionResistancePriority="250" fixedFrame="YES" allowsCharacterPickerTouchBarItem="YES" translatesAutoresizingMaskIntoConstraints="NO" id="6qu-yI-r00">
                         <rect key="frame" x="413" y="20" width="203" height="11"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                         <textFieldCell key="cell" lineBreakMode="truncatingTail" sendsActionOnEndEditing="YES" title="The AirPlay Logo is a trademark of Apple Inc." id="lx7-k3-q16">
-                            <font key="font" metaFont="miniSystem"/>
+                            <font key="font" metaFont="menu" size="9"/>
                             <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
                             <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                         </textFieldCell>
                     </textField>
-                    <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" tag="2" allowsCharacterPickerTouchBarItem="YES" translatesAutoresizingMaskIntoConstraints="NO" id="Vy4-dv-jQB">
-                        <rect key="frame" x="18" y="75" width="346" height="17"/>
+                    <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" tag="2" allowsCharacterPickerTouchBarItem="YES" translatesAutoresizingMaskIntoConstraints="NO" id="Vy4-dv-jQB">
+                        <rect key="frame" x="18" y="75" width="155" height="16"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
-                        <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" alignment="center" title="Copyright © 2016-2019 Background Music contributors" placeholderString="" id="ctF-95-uVu">
+                        <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" alignment="center" title="Copyright © 2016-2024" placeholderString="" id="ctF-95-uVu">
                             <font key="font" metaFont="system"/>
                             <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
                             <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                         </textFieldCell>
                     </textField>
+                    <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" tag="4" allowsCharacterPickerTouchBarItem="YES" translatesAutoresizingMaskIntoConstraints="NO" id="tRj-QC-GuQ" customClass="BGMLinkField">
+                        <rect key="frame" x="168" y="75" width="194" height="16"/>
+                        <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
+                        <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" selectable="YES" sendsActionOnEndEditing="YES" alignment="left" tag="3" title="Background Music contributors" placeholderString="" allowsEditingTextAttributes="YES" usesSingleLineMode="YES" id="UC2-MX-fML">
+                            <font key="font" metaFont="system"/>
+                            <color key="textColor" red="0.20000000000000001" green="0.40000000000000002" blue="0.59999999999999998" alpha="1" colorSpace="calibratedRGB"/>
+                            <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
+                        </textFieldCell>
+                    </textField>
                 </subviews>
             </view>
             <point key="canvasLocation" x="-200" y="232.5"/>
         </window>
-        <textField verticalHuggingPriority="750" horizontalCompressionResistancePriority="250" setsMaxLayoutWidthAtFirstLayout="YES" allowsCharacterPickerTouchBarItem="YES" id="IoN-sN-cCx">
+        <textField focusRingType="none" verticalHuggingPriority="750" horizontalCompressionResistancePriority="250" setsMaxLayoutWidthAtFirstLayout="YES" allowsCharacterPickerTouchBarItem="YES" id="IoN-sN-cCx">
             <rect key="frame" x="0.0" y="0.0" width="471" height="180"/>
             <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
             <textFieldCell key="cell" controlSize="mini" sendsActionOnEndEditing="YES" drawsBackground="YES" id="Ay8-8n-FHi">
@@ -281,10 +293,10 @@
                 <slider identifier="Output Volume" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="9Ru-Sc-dqC" userLabel="Output Volume Slider">
                     <rect key="frame" x="20" y="4" width="220" height="19"/>
                     <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
-                    <sliderCell key="cell" continuous="YES" state="on" alignment="left" maxValue="1" tickMarkPosition="above" sliderType="linear" id="MzM-fe-nKb"/>
+                    <sliderCell key="cell" controlSize="small" continuous="YES" state="on" alignment="left" maxValue="1" tickMarkPosition="above" sliderType="linear" id="MzM-fe-nKb"/>
                     <accessibility description="Output Volume" help="Sets the volume of your audio output device." identifier="Output Volume"/>
                 </slider>
-                <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="wfC-C6-SLv">
+                <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="wfC-C6-SLv">
                     <rect key="frame" x="20" y="25" width="226" height="17"/>
                     <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                     <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Volume" id="60O-ju-B5C">
@@ -303,10 +315,10 @@
                 <slider identifier="System Sounds Volume" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="gyd-WV-2ju" userLabel="Output Volume Slider">
                     <rect key="frame" x="163" y="0.0" width="74" height="15"/>
                     <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
-                    <sliderCell key="cell" controlSize="small" continuous="YES" state="on" alignment="left" maxValue="1" doubleValue="1" tickMarkPosition="above" sliderType="linear" id="VDn-d8-XK3"/>
+                    <sliderCell key="cell" controlSize="mini" continuous="YES" state="on" alignment="left" maxValue="1" doubleValue="1" tickMarkPosition="above" sliderType="linear" id="VDn-d8-XK3"/>
                     <accessibility description="System Sounds Volume" help="Volume of alerts, notification sounds, etc. Usually short. Can be played by any app."/>
                 </slider>
-                <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="iKs-df-Hp6">
+                <textField focusRingType="none" horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="iKs-df-Hp6">
                     <rect key="frame" x="42" y="1" width="86" height="14"/>
                     <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
                     <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="System Sounds" id="ATK-L8-s8z">
@@ -330,53 +342,54 @@
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 </mutableData>
         </image>
     </resources>

BGMApp/BGMApp/Info.plist

@@ -17,7 +17,7 @@
 	<key>CFBundlePackageType</key>
 	<string>APPL</string>
 	<key>CFBundleShortVersionString</key>
-	<string>0.3.1</string>
+	<string>0.4.3</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
@@ -33,7 +33,7 @@
 	<key>NSAppleScriptEnabled</key>
 	<true/>
 	<key>NSHumanReadableCopyright</key>
-	<string>Copyright © 2016-2019 Background Music contributors</string>
+	<string>Copyright © 2016-2024 Background Music contributors</string>
 	<key>NSMainNibFile</key>
 	<string>MainMenu</string>
 	<key>NSMicrophoneUsageDescription</key>
@@ -46,5 +46,11 @@
 	</array>
 	<key>OSAScriptingDefinition</key>
 	<string>BGMApp.sdef</string>
+    <!--
+    Hopefully this will keep Background Music from using the discrete GPU on multi-GPU systems,
+    which wastes energy. I don't have any hardware I could easily test this on, so it's untested.
+    -->
+	<key>NSSupportsAutomaticGraphicsSwitching</key>
+	<true/>
 </dict>
 </plist>

BGMApp/BGMApp/Music Players/BGMMusicPlayer.m

@@ -92,7 +92,11 @@
 
 + (NSArray<id<BGMMusicPlayer>>*) createInstancesWithDefaults:(BGMUserDefaults*)userDefaults {
     #pragma unused (userDefaults)
+    // TODO: Fix this warning properly.
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wobjc-literal-conversion"
     return @[ [self new] ];
+#pragma clang diagnostic pop
 }
 
 - (NSImage* __nullable) icon {

BGMApp/BGMApp/Music Players/BGMMusicPlayers.mm

@@ -146,7 +146,7 @@
 - (void) initSelectedMusicPlayerFromBGMDevice {
     // When the selected music player setting hasn't been stored in user defaults yet, we get the music player
     // bundle ID from the driver and look for the music player with that bundle ID. This is mainly done for
-    // backwards compatability.
+    // backwards compatibility.
     
     NSString* __nullable bundleID =
         (__bridge_transfer NSString* __nullable)[audioDevices bgmDevice].GetMusicPlayerBundleID();

BGMApp/BGMApp/Music Players/BGMVLC.m

@@ -18,7 +18,7 @@
 //  BGMApp
 //
 //  Copyright © 2016-2018 Kyle Neideck
-//  Portions copyright (C) 2012 Peter Ljunglöf. All rights reserved.
+//  Copyright (C) 2012 Peter Ljunglöf. All rights reserved.
 //
 
 // Self Include

BGMApp/BGMApp/Music Players/VLC.h

@@ -221,7 +221,7 @@ typedef enum VLCEnum VLCEnum;
 @property NSInteger audioVolume;  // The volume of the current playlist item from 0 to 4, where 4 is 400%
 @property NSInteger currentTime;  // The current time of the current playlist item in seconds.
 @property (readonly) NSInteger durationOfCurrentItem;  // The duration of the current playlist item in seconds.
-@property BOOL fullscreenMode;  // indicates wheter fullscreen is enabled or not
+@property BOOL fullscreenMode;  // indicates whether fullscreen is enabled or not
 @property (readonly) BOOL muted;  // Is VLC currently muted?
 @property (copy, readonly) NSString *nameOfCurrentItem;  // Name of the current playlist item.
 @property (copy, readonly) NSString *pathOfCurrentItem;  // Path to the current playlist item.

BGMApp/BGMApp/Music Players/VOX.h

@@ -37,7 +37,7 @@
 - (void) rewindForwardFast;  // Rewind current track forward fast.
 - (void) rewindBackward;  // Rewind current track backward.
 - (void) rewindBackwardFast;  // Rewind current track backward fast.
-- (void) increasVolume;  // Increas volume.
+- (void) increasVolume;  // Increase volume.
 - (void) decreaseVolume;  // Decrease volume.
 - (void) showHidePlaylist;  // Show/Hide playlist.
 
@@ -62,7 +62,7 @@
 @property (copy, readonly) NSString *album;  // Current track album.
 @property (copy, readonly) NSString *uniqueID;  // Unique identifier for the current track.
 @property double currentTime;  // The current playback position.
-@property (readonly) double totalTime;  // The total time of the currenty playing track.
+@property (readonly) double totalTime;  // The total time of the currently playing track.
 @property double playerVolume;  // Player volume (0.0 to 1.0)
 @property NSInteger repeatState;  // Player repeat state (none = 0, repeat one = 1, repeat all = 2)
 

BGMApp/BGMApp/Preferences/BGMAboutPanel.m

@@ -17,7 +17,7 @@
 //  BGMAboutPanel.m
 //  BGMApp
 //
-//  Copyright © 2016 Kyle Neideck
+//  Copyright © 2016, 2024 Kyle Neideck
 //
 
 // Self Include
@@ -35,6 +35,7 @@ NS_ASSUME_NONNULL_BEGIN
 static NSInteger const kVersionLabelTag = 1;
 static NSInteger const kCopyrightLabelTag = 2;
 static NSInteger const kProjectWebsiteLabelTag = 3;
+static NSInteger const kContributorsLabelTag = 4;
 
 @implementation BGMAboutPanel {
     NSPanel* aboutPanel;
@@ -42,6 +43,7 @@ static NSInteger const kProjectWebsiteLabelTag = 3;
     NSTextField* versionLabel;
     NSTextField* copyrightLabel;
     NSTextField* websiteLabel;
+    NSTextField* contributorsLabel;
     
     NSTextView* licenseView;
 }
@@ -53,6 +55,7 @@ static NSInteger const kProjectWebsiteLabelTag = 3;
         versionLabel = [[aboutPanel contentView] viewWithTag:kVersionLabelTag];
         copyrightLabel = [[aboutPanel contentView] viewWithTag:kCopyrightLabelTag];
         websiteLabel = [[aboutPanel contentView] viewWithTag:kProjectWebsiteLabelTag];
+        contributorsLabel = [[aboutPanel contentView] viewWithTag:kContributorsLabelTag];
         
         licenseView = inLicenseView;
         
@@ -83,7 +86,10 @@ static NSInteger const kProjectWebsiteLabelTag = 3;
             [[bundle infoDictionary] objectForKey:@"NSHumanReadableCopyright"];
         
         if (copyrightNotice) {
-            copyrightLabel.stringValue = (NSString*)copyrightNotice;
+            // Remove the part that we replace with a link.
+            copyrightLabel.stringValue =
+                [((NSString*)copyrightNotice) stringByReplacingOccurrencesOfString:contributorsLabel.stringValue
+                                                                        withString:@""];
         }
         
         // Project website link label
@@ -97,6 +103,18 @@ static NSInteger const kProjectWebsiteLabelTag = 3;
                                             attributes:@{ NSLinkAttributeName: projectURL,
                                                           NSFontAttributeName: linkFont }];
         
+        // Contributors link label
+        // TODO: Proper credits (i.e. in the app instead of just a link)
+        contributorsLabel.selectable = YES;
+        contributorsLabel.allowsEditingTextAttributes = YES;
+        
+        NSString* contributorsURL = [NSString stringWithUTF8String:kBGMContributorsURL];
+        NSFont* cLinkFont = contributorsLabel.font ? contributorsLabel.font : [NSFont labelFontOfSize:0.0];
+        contributorsLabel.attributedStringValue =
+            [[NSAttributedString alloc] initWithString:contributorsLabel.stringValue
+                                            attributes:@{ NSLinkAttributeName: contributorsURL,
+                                                          NSFontAttributeName: cLinkFont }];
+        
         // Load the text of the license into the text view
         NSString* __nullable licensePath = [bundle pathForResource:@"LICENSE" ofType:nil];
         
@@ -122,9 +140,25 @@ static NSInteger const kProjectWebsiteLabelTag = 3;
 
 - (void) show {
     DebugMsg("BGMAboutPanel::showAboutPanel: Opening \"About Background Music\" panel");
-    [NSApp activateIgnoringOtherApps:YES];
+    
+    // We have to make aboutPanel visible before calling [NSApp activateIgnoringOtherApps:YES]
+    // or the app won't be activated the first time (not sure why it only happens the first
+    // time) and aboutPanel won't open. WindowServer logs this explanation:
+    // 0[SetFrontProcessWithInfo]: CPS: Rejecting the request for pid 1234 due to the activation count being 0; launch ts=19302059379458, current time=19314267188375, window count = 0.
     [aboutPanel setIsVisible:YES];
     [aboutPanel makeKeyAndOrderFront:self];
+    
+    // On macOS 14.4, aboutPanel needs "Release When Closed" unchecked in MainMenu.xib. Otherwise,
+    // aboutPanel will never open again if you click the close button.
+    
+    // This is deprecated for NSApplication.activate, but that stops aboutPanel from ever being shown.
+    [NSApp activateIgnoringOtherApps:YES];
+    
+    DebugMsg("BGMAboutPanel::showAboutPanel: Finished opening panel. "
+             "aboutPanel.isVisible %d, aboutPanel.isKeyWindow %d, NSApp.isActive %d",
+             aboutPanel.isVisible,
+             aboutPanel.isKeyWindow,
+             NSApp.isActive);
 }
 
 @end

BGMApp/BGMApp/Scripting/BGMASApplication.h

@@ -0,0 +1,50 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  BGMASApplication.h
+//  BGMApp
+//
+//  Copyright © 2021 Marcus Wu
+//  Copyright © 2021 Kyle Neideck
+//
+//  An AppleScript class for volume and pan settings for running applications.
+//
+
+
+// Local Includes
+#import "BGMAppVolumesController.h"
+
+// System Includes
+#import <Foundation/Foundation.h>
+#import <Cocoa/Cocoa.h>
+
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface BGMASApplication : NSObject
+
+- (instancetype) initWithApplication:(NSRunningApplication*)app
+                          volumeController:(BGMAppVolumesController*)volumeController
+                     parentSpecifier:(NSScriptObjectSpecifier* __nullable)parentSpecifier
+                               index:(int)i;
+
+@property (readonly) NSString* name;
+@property (readonly) NSString* bundleID;
+@property int volume;
+@property int pan;
+@end
+
+NS_ASSUME_NONNULL_END

BGMApp/BGMApp/Scripting/BGMASApplication.m

@@ -0,0 +1,91 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  BGMASApplication.m
+//  BGMApp
+//
+//  Copyright © 2021 Marcus Wu
+//  Copyright © 2021 Kyle Neideck
+//
+
+// Self Include
+#import "BGMASApplication.h"
+
+// Local Includes
+#import "BGM_Types.h"
+
+@implementation BGMASApplication {
+    NSScriptObjectSpecifier* parentSpecifier;
+    NSRunningApplication *application;
+    BGMAppVolumesController* appVolumesController;
+    int index;
+}
+
+- (instancetype) initWithApplication:(NSRunningApplication*)app
+                          volumeController:(BGMAppVolumesController*)volumeController
+                     parentSpecifier:(NSScriptObjectSpecifier* __nullable)parent
+                               index:(int)i {
+    if ((self = [super init])) {
+        parentSpecifier = parent;
+        application = app;
+        appVolumesController = volumeController;
+        index = i;
+    }
+
+    return self;
+}
+
+- (NSString*) name {
+    return [NSString stringWithFormat:@"%@", [application localizedName]];
+}
+
+- (NSString*) bundleID {
+    return [NSString stringWithFormat:@"%@", [application bundleIdentifier]];
+}
+
+- (int) volume {
+    return [appVolumesController getVolumeAndPanForApp:application].volume;
+}
+
+- (void) setVolume:(int)vol {
+    BGMAppVolumeAndPan volume = {
+        .volume = vol,
+        .pan = kAppPanNoValue
+    };
+    [appVolumesController setVolumeAndPan:volume forApp:application];
+}
+
+- (int) pan {
+    return [appVolumesController getVolumeAndPanForApp:application].pan;
+}
+
+- (void) setPan:(int)pan {
+    BGMAppVolumeAndPan thePan = {
+        .volume = -1,
+        .pan = pan
+    };
+    [appVolumesController setVolumeAndPan:thePan forApp:application];
+}
+
+- (NSScriptObjectSpecifier* __nullable) objectSpecifier {
+    NSScriptClassDescription* parentClassDescription = [parentSpecifier keyClassDescription];
+    return [[NSNameSpecifier alloc] initWithContainerClassDescription:parentClassDescription
+                                                   containerSpecifier:parentSpecifier
+                                                                  key:@"applications"
+                                                                 name:self.name];
+}
+
+@end

BGMApp/BGMApp/Scripting/BGMApp.sdef

@@ -9,8 +9,7 @@
         <class name="output device"
                code="aDev"
                description="A hardware device that can play audio"
-               plural="output devices"
-               inherits="item">
+               plural="output devices">
             <synonym name="audio device"/>
 
             <cocoa class="BGMASOutputDevice"/>
@@ -19,14 +18,58 @@
                       code="pnam"
                       description="The name of the output device."
                       type="text"
-                      access="r"/>
+                      access="r">
+                <cocoa key="name"/>
+            </property>
 
             <property name="selected"
                       code="Slcd"
                       type="boolean"
                       access="rw"
                       description="Is this the device to be used for audio output?">
-                <synonym name="default"/>
+		<synonym name="default"/>
+                <cocoa key="selected"/>
+            </property>
+        </class>
+
+        <class name="audio application"
+               code="aApp"
+               description="An application that can play audio"
+               plural="audio applications">
+            <synonym name="audio app"/>
+
+            <cocoa class="BGMASApplication"/>
+
+            <property name="name"
+                      code="pnam"
+                      description="The name of the application."
+                      type="text"
+                      access="r">
+                <cocoa key="name"/>
+            </property>
+
+            <property name="bundleID"
+                      code="bdid"
+                      description="The bundle ID of the application, e.g. 'com.somecompany.coolapp'."
+                      type="text"
+                      access="r">
+                <cocoa key="bundleID"/>
+            </property>
+
+            <property name="vol"
+                      code="pVol"
+                      type="integer"
+                      access="rw"
+                      description="The volume setting of the application">
+                <cocoa key="volume"/>
+            </property>
+
+            <property name="pan"
+                      code="pPan"
+                      type="integer"
+                      access="rw"
+                      description="The pan setting of the application">
+                <cocoa key="pan"/>
             </property>
         </class>
 
@@ -48,11 +91,23 @@
 
                 <cocoa key="selectedOutputDevice"/>
             </property>
+            <property name="output volume"
+                type="real"
+                code="oVol"
+                access="rw"
+                description="The main output volume">
+                <synonym name="main volume"/>
+
+                <cocoa key="mainVolume"/>
+            </property>
 
             <!-- Unintuitively, this is for the array of output devices. -->
             <element type="output device" access="r">
                 <cocoa key="outputDevices"/>
             </element>
+            <element type="audio application" access="r">
+                <cocoa key="applications"/>
+            </element>
         </class>
     </suite>
 </dictionary>

BGMApp/BGMApp/Scripting/BGMAppDelegate+AppleScript.h

@@ -18,12 +18,18 @@
 //  BGMApp
 //
 //  Copyright © 2017 Kyle Neideck
+//  Copyright © 2021 Marcus Wu
 //
 
 #import "BGMAppDelegate.h"
 
+// Local Includes
+#import "BGMAudioDeviceManager.h"
+#import "BGMAppVolumesController.h"
+
 // Local Includes
 #import "BGMASOutputDevice.h"
+#import "BGMASApplication.h"
 
 // System Includes
 #import <Foundation/Foundation.h>
@@ -37,6 +43,8 @@
 
 @property BGMASOutputDevice* selectedOutputDevice;
 @property (readonly) NSArray<BGMASOutputDevice*>* outputDevices;
+@property double mainVolume;
+@property (readonly) NSArray<BGMASApplication*>* applications;
 
 @end
 

BGMApp/BGMApp/Scripting/BGMAppDelegate+AppleScript.mm

@@ -18,6 +18,7 @@
 //  BGMApp
 //
 //  Copyright © 2017 Kyle Neideck
+//  Copyright © 2021 Marcus Wu
 //
 
 // Self Include
@@ -30,6 +31,7 @@
 #import "CAHALAudioSystemObject.h"
 #import "CAAutoDisposer.h"
 
+const AudioObjectPropertyScope kScope                   = kAudioDevicePropertyScopeOutput;
 
 #pragma clang assume_nonnull begin
 
@@ -43,7 +45,7 @@
                  [key UTF8String]);
     }
 
-    return [@[@"selectedOutputDevice", @"outputDevices"] containsObject:key];
+    return [@[@"selectedOutputDevice", @"outputDevices", @"mainVolume", @"applications"] containsObject:key];
 }
 
 - (BGMASOutputDevice*) selectedOutputDevice {
@@ -83,6 +85,30 @@
     return outputDevices;
 }
 
+- (double) mainVolume {
+    BGMAudioDevice bgmDevice = [self.audioDevices bgmDevice];
+    return bgmDevice.GetVolumeControlScalarValue(kScope, kMasterChannel);
+}
+
+- (void) setMainVolume:(double)mainVolume {
+    BGMAudioDevice bgmDevice = [self.audioDevices bgmDevice];
+    bgmDevice.SetMasterVolumeScalar(kScope, (Float32)mainVolume);
+    [self.outputVolumeSlider setFloatValue:(float)mainVolume];
+}
+
+- (NSArray<BGMASApplication*>*) applications {
+    NSArray<NSRunningApplication*>* apps = [[NSWorkspace sharedWorkspace] runningApplications];
+    NSMutableArray<BGMASApplication*>* applications = [NSMutableArray arrayWithCapacity:[apps count]];
+
+    for (UInt32 i = 0; i < [apps count]; i++) {
+        BGMASApplication *app = [[BGMASApplication alloc] initWithApplication:apps[i] volumeController:self.appVolumes parentSpecifier:[self objectSpecifier] index:i];
+
+        [applications addObject:app];
+    }
+
+    return applications;
+}
+
 @end
 
 #pragma clang assume_nonnull end

BGMApp/BGMApp/_uninstall-non-interactive.sh

@@ -20,7 +20,7 @@
 # _uninstall-non-interactive.sh
 #
 # Copyright © 2016 Nick Jacques
-# Copyright © 2016, 2017 Kyle Neideck
+# Copyright © 2016, 2017, 2021 Kyle Neideck
 #
 # Removes BGMApp, BGMDriver and BGMXPCHelper from the system immediately. Run by uninstall.sh and the Homebrew formula.
 #
@@ -43,8 +43,9 @@ driver_path="/Library/Audio/Plug-Ins/HAL/Background Music Device.driver"
 xpc_path1="/usr/local/libexec/BGMXPCHelper.xpc"
 xpc_path2="/Library/Application Support/Background Music/BGMXPCHelper.xpc"
 
-# Check that files/directories are at most this big before we delete them, just to be safe.
-max_size_mb_for_rm=15
+# Check that files/directories are at most this big before we delete them, just to be safe. Note that the bundles can
+# include debug symbols, e.g. if you use build_and_install.sh, which makes them a lot bigger.
+max_size_mb_for_rm=30
 
 file_paths=("${app_path}" "${driver_path}" "${xpc_path1}" "${xpc_path2}")
 
@@ -68,8 +69,9 @@ function size_check {
   [[ "${size}" =~ ^[0-9]+$ ]] && [[ "${size}" -le ${max_size_mb_for_rm} ]]
 }
 
-# Ensure that the user can use sudo. (But not if this is a Travis CI build, because then it would fail.)
-if ([[ -z ${TRAVIS:-} ]] || [[ "${TRAVIS}" != true ]]) && ! sudo -v; then
+# Ensure that the user can use sudo. (Use `sudo true` instead of `sudo -v` because that causes a
+# password prompt in Travis CI builds for some reason.)
+if ! sudo true; then
   echo "ERROR: This script must be run by a user with administrator (sudo) privileges." >&2
   exit 1
 fi
@@ -137,20 +139,21 @@ sleep 2
 # The extra or-clauses are fallback versions of the command that restarts coreaudiod. Apparently some of these commands 
 # don't work with older versions of launchctl, so I figure there's no harm in trying a bunch of different ways until
 # one works.
-(sudo launchctl kill SIGTERM system/com.apple.audio.coreaudiod &>/dev/null || \
+(sudo launchctl kickstart -k system/com.apple.audio.coreaudiod &>/dev/null || \
+  sudo killall coreaudiod &>/dev/null || \
+  sudo launchctl kill SIGTERM system/com.apple.audio.coreaudiod &>/dev/null || \
   sudo launchctl kill TERM system/com.apple.audio.coreaudiod &>/dev/null || \
   sudo launchctl kill 15 system/com.apple.audio.coreaudiod &>/dev/null || \
   sudo launchctl kill -15 system/com.apple.audio.coreaudiod &>/dev/null || \
   (sudo launchctl unload "${coreaudiod_plist}" &>/dev/null && \
-    sudo launchctl load "${coreaudiod_plist}" &>/dev/null) || \
-  sudo killall coreaudiod &>/dev/null)
+    sudo launchctl load "${coreaudiod_plist}" &>/dev/null))
 
 echo "..."
 sleep 3
 
 # TODO: What if they only have one audio device?
 echo ""
-echo "${bold}Done! Toggle your audio output device in the Sound section of System Preferences to finish" \
+echo "${bold}Done! Toggle your audio output device in the Sound section of System Settings to finish" \
      "uninstalling. (Or just restart your computer.)${normal}"
 
 

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-				CLANG_WARN__EXIT_TIME_DESTRUCTORS = NO;
-				GCC_PREPROCESSOR_DEFINITIONS = "DEBUG=1";
-				INFOPLIST_FILE = "SimpleAudio/Driver/SimpleAudioDriver-Info.plist";
-				INSTALL_PATH = "$(SYSTEM_LIBRARY_DIR)/Extensions";
-				MODULE_NAME = com.apple.audio.SimpleAudioDriver;
-				MODULE_VERSION = 1.0;
-				PRODUCT_NAME = "$(TARGET_NAME)";
-				WRAPPER_EXTENSION = kext;
-			};
-			name = Debug;
-		};
-		2DED184815C357180091BE97 /* Debug-Opt */ = {
-			isa = XCBuildConfiguration;
-			buildSettings = {
-				CLANG_WARN__EXIT_TIME_DESTRUCTORS = NO;
-				GCC_PREPROCESSOR_DEFINITIONS = "DEBUG=1";
-				INFOPLIST_FILE = "SimpleAudio/Driver/SimpleAudioDriver-Info.plist";
-				INSTALL_PATH = "$(SYSTEM_LIBRARY_DIR)/Extensions";
-				MODULE_NAME = com.apple.audio.SimpleAudioDriver;
-				MODULE_VERSION = 1.0;
-				PRODUCT_NAME = "$(TARGET_NAME)";
-				WRAPPER_EXTENSION = kext;
-			};
-			name = "Debug-Opt";
-		};
-/* End XCBuildConfiguration section */
-
-/* Begin XCConfigurationList section */
-		2D7477A01578162B00412279 /* Build configuration list for PBXProject "AudioDriverExamples" */ = {
-			isa = XCConfigurationList;
-			buildConfigurations = (
-				2D7477A21578162B00412279 /* Release */,
-				2D7477A31578162B00412279 /* Debug */,
-				2D7477A41578164E00412279 /* Debug-Opt */,
-			);
-			defaultConfigurationIsVisible = 0;
-			defaultConfigurationName = Release;
-		};
-		2D7477B51578168D00412279 /* Build configuration list for PBXNativeTarget "NullAudio" */ = {
-			isa = XCConfigurationList;
-			buildConfigurations = (
-				2D7477B61578168D00412279 /* Release */,
-				2D7477B71578168D00412279 /* Debug */,
-				2D7477B81578168D00412279 /* Debug-Opt */,
-			);
-			defaultConfigurationIsVisible = 0;
-			defaultConfigurationName = Release;
-		};
-		2D76D97215E48B2000FF0F33 /* Build configuration list for PBXNativeTarget "SimpleAudioPlugIn" */ = {
-			isa = XCConfigurationList;
-			buildConfigurations = (
-				2D76D96F15E48B2000FF0F33 /* Release */,
-				2D76D97015E48B2000FF0F33 /* Debug */,
-				2D76D97115E48B2000FF0F33 /* Debug-Opt */,
-			);
-			defaultConfigurationIsVisible = 0;
-			defaultConfigurationName = Release;
-		};
-		2DED184515C357180091BE97 /* Build configuration list for PBXNativeTarget "SimpleAudioDriver" */ = {
-			isa = XCConfigurationList;
-			buildConfigurations = (
-				2DED184615C357180091BE97 /* Release */,
-				2DED184715C357180091BE97 /* Debug */,
-				2DED184815C357180091BE97 /* Debug-Opt */,
-			);
-			defaultConfigurationIsVisible = 0;
-			defaultConfigurationName = Release;
-		};
-/* End XCConfigurationList section */
-	};
-	rootObject = 2D74779D1578162B00412279 /* Project object */;
-}

BGMApp/BGMAppTests/NullAudio/AudioDriverExamples.xcodeproj/project.xcworkspace/contents.xcworkspacedata

@@ -1,7 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<Workspace
-   version = "1.0">
-   <FileRef
-      location = "self:">
-   </FileRef>
-</Workspace>

BGMApp/BGMAppTests/NullAudio/NullAudio/NullAudio-Info.plist

@@ -1,38 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
-<plist version="1.0">
-<dict>
-	<key>CFBundleDevelopmentRegion</key>
-	<string>English</string>
-	<key>CFBundleExecutable</key>
-	<string>${EXECUTABLE_NAME}</string>
-	<key>CFBundleIconFile</key>
-	<string></string>
-	<key>CFBundleIdentifier</key>
-	<string>com.apple.audio.${PRODUCT_NAME:rfc1034identifier}</string>
-	<key>CFBundleInfoDictionaryVersion</key>
-	<string>6.0</string>
-	<key>CFBundleName</key>
-	<string>${PRODUCT_NAME}</string>
-	<key>CFBundlePackageType</key>
-	<string>BNDL</string>
-	<key>CFBundleShortVersionString</key>
-	<string>1.0.1</string>
-	<key>CFBundleSignature</key>
-	<string>????</string>
-	<key>CFBundleVersion</key>
-	<string>1</string>
-	<key>CFPlugInFactories</key>
-	<dict>
-		<key>99A15A8B-DA3C-42C3-BD5D-D035A0C2377A</key>
-		<string>NullAudio_Create</string>
-	</dict>
-	<key>CFPlugInTypes</key>
-	<dict>
-		<key>443ABAB8-E7B3-491A-B985-BEB9187030DB</key>
-		<array>
-			<string>99A15A8B-DA3C-42C3-BD5D-D035A0C2377A</string>
-		</array>
-	</dict>
-</dict>
-</plist>

BGMApp/BGMAppTests/NullAudio/README

@@ -1,6 +0,0 @@
-TravisCI's OS X VMs don't have any audio devices installed by default, so we
-install Apple's NullAudio sample driver before the tests run. Otherwise the
-tests would fail because BGMApp currently crashes on launch if you don't have
-any audio devices.
-
-

BGMApp/BGMAppTests/UITests/BGMAppUITests.mm

@@ -17,7 +17,7 @@
 //  BGMAppUITests.mm
 //  BGMAppUITests
 //
-//  Copyright © 2017, 2018 Kyle Neideck
+//  Copyright © 2017, 2018, 2020, 2022 Kyle Neideck
 //
 //  You might want to use Xcode's UI test recording feature if you add new tests.
 //
@@ -30,8 +30,10 @@
 // Scripting Bridge Includes
 #import "BGMApp.h"
 
+// System Includes
+#import <XCTest/XCTest.h>
+
 
-// TODO: Skip these tests if macOS SDK 10.11 or higher isn't available.
 // TODO: Mock BGMDevice and music players.
 
 #if __clang_major__ >= 9
@@ -72,22 +74,55 @@
     // would fail to start because of a bug in Xcode.
     app.launchArguments = @[ @"--no-persistent-data", @"--show-dock-icon" ];
 
+    // Make the "Background Music wants to use the microphone" dialog appear every time so the test
+    // doesn't need logic to handle both cases.
+    // TODO: Commented out until acceptMicrophoneAuthorizationDialog work again. See below.
+    // if (@available(macOS 10.15.4, *)) {
+    //     [app resetAuthorizationStatusForResource:XCUIProtectedResourceMicrophone];
+    // }
+
     // Launch BGMApp.
     [app launch];
 
-     if (![icon waitForExistenceWithTimeout:1.0]) {
+    // TODO: This doesn't seem to be working on macOS 12.4 (21F79). You can click OK manually for
+    //       now.
+    // [self acceptMicrophoneAuthorizationDialog];
+
+    if (![icon waitForExistenceWithTimeout:20.0]) {
         // The status bar icon/button has this type when using older versions of XCTest, so try
         // both. (Actually, it might depend on the macOS or Xcode version. I'm not sure.)
         XCUIElement* iconOldType =
-                [app.menuBars childrenMatchingType:XCUIElementTypeMenuBarItem].element;
-         if (![iconOldType waitForExistenceWithTimeout:5.0]) {
-             icon = iconOldType;
-         }
+            [app.menuBars childrenMatchingType:XCUIElementTypeMenuBarItem].element;
+        if ([iconOldType waitForExistenceWithTimeout:20.0]) {
+            NSLog(@"icon = iconOldType");
+            icon = iconOldType;
+        }
     }
 
     // Wait for the initial elements.
-    XCTAssert([app waitForExistenceWithTimeout:10.0]);
-    XCTAssert([icon waitForExistenceWithTimeout:10.0]);
+    XCTAssert([app waitForExistenceWithTimeout:20.0]);
+    XCTAssert([icon waitForExistenceWithTimeout:20.0]);
+}
+
+// Clicks the OK button in the "Background Music wants to use the microphone" dialog.
+- (void) acceptMicrophoneAuthorizationDialog {
+    XCUIApplication* unc =
+        [[XCUIApplication alloc] initWithBundleIdentifier:@"com.apple.UserNotificationCenter"];
+    NSLog(@"UserNotificationCenter: %@", unc);
+    XCUIElement* okButton = unc.dialogs.buttons[@"OK"];
+
+    XCTAssert([okButton waitForExistenceWithTimeout:20.0]);
+
+    // This click is failing on GH Actions. No idea why, so try a sleep.
+    (void)[XCTWaiter waitForExpectations:@[[XCTestExpectation new]] timeout:5.0];
+    [okButton click];
+
+    int retries = 10;
+    while (retries > 0 && [okButton waitForExistenceWithTimeout:3.0]) {
+        NSLog(@"Microphone authorization dialog is still open. Trying to click OK again.");
+        [okButton click];
+        retries--;
+    }
 }
 
 - (void) tearDown {
@@ -99,13 +134,13 @@
     [menuItems[@"Quit Background Music"] click];
 
     // BGMApp should quit.
-    XCTAssert(!app.exists);
+    XCTAssertTrue([app waitForState:XCUIApplicationStateNotRunning timeout:10.0]);
     
     [super tearDown];
 }
 
 - (void) testCycleOutputDevices {
-    const int NUM_CYCLES = 2;
+    const int NUM_CYCLES = 1;
 
     // sbApp lets us use AppleScript to query BGMApp and check the test has made the changes to its
     // settings we expect.

BGMApp/BGMAppTests/UITests/skip-ui-tests.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python2.7
+#!/usr/bin/env python3
 
 # This file is part of Background Music.
 #
@@ -16,20 +16,12 @@
 # along with Background Music. If not, see <http://www.gnu.org/licenses/>.
 
 #
-# travis-skip.py
+# skip-ui-tests.py
 # BGMAppUITests
 #
-# Copyright (c) 2017 Kyle Neideck
+# Copyright (c) 2017, 2024 Kyle Neideck
 #
-# Skip the UI tests in Travis builds because they aren't supported.
-#
-# We can't run the tests on Travis because Xcode needs permission to use the Accessibility API
-# to control BGMApp. There's no way to set that up programmatically without disabling SIP and
-# Travis doesn't support that.
-#
-# See https://github.com/travis-ci/travis-ci/issues/5819
-#
-# TODO: Figure out a better way to do this.
+# Disables the UI tests. This is mainly useful on CI systems that don't support UI tests.
 #
 
 import xml.etree.ElementTree as ET
@@ -46,4 +38,3 @@ tree.getroot().findall(UI_REF_XPATH)[0].set("skipped", "YES")
 # Save the scheme.
 tree.write(SCHEME_FILE)
 
-

BGMApp/BGMAppTests/UnitTests/BGMMusicPlayersUnitTests.mm

@@ -17,24 +17,28 @@
 //  BGMMusicPlayersUnitTests.mm
 //  BGMAppUnitTests
 //
-//  Copyright © 2016-2018 Kyle Neideck
+//  Copyright © 2016-2020 Kyle Neideck
 //
 
 // Unit include
 #import "BGMMusicPlayers.h"
 
-// Local includes
-#import "BGM_TestUtils.h"
-
+// BGM includes
 #import "BGM_Types.h"
 #import "BGMAudioDeviceManager.h"
 #import "BGMiTunes.h"
-#import "BGMVLC.h"
 #import "BGMDecibel.h"
 #import "BGMSpotify.h"
+#import "BGMVLC.h"
+
+// Local includes
+#import "BGM_TestUtils.h"
+#import "MockAudioObject.h"
+#import "MockAudioObjects.h"
 
 // System includes
 #import <Foundation/Foundation.h>
+#import <XCTest/XCTest.h>
 
 
 // Note that the PublicUtility classes that we use to communicate with the HAL, CAHALAudioObject and
@@ -72,32 +76,6 @@
 
 // -------------------------------------------------------------------------------------------------
 
-class BGMMockBackgroundMusicDevice
-:
-    public BGMBackgroundMusicDevice
-{
-
-public:
-    CFStringRef GetMusicPlayerBundleID() const;
-    void        SetMusicPlayerBundleID(CFStringRef inBundleID);
-
-private:
-    CFStringRef mMusicPlayerBundleID = CFSTR("");
-
-};
-
-CFStringRef BGMMockBackgroundMusicDevice::GetMusicPlayerBundleID() const
-{
-    return mMusicPlayerBundleID;
-}
-
-void BGMMockBackgroundMusicDevice::SetMusicPlayerBundleID(CFStringRef inBundleID)
-{
-    mMusicPlayerBundleID = inBundleID;
-}
-
-// -------------------------------------------------------------------------------------------------
-
 @interface BGMMockAudioDeviceManager : BGMAudioDeviceManager
 @end
 
@@ -127,6 +105,10 @@ void BGMMockBackgroundMusicDevice::SetMusicPlayerBundleID(CFStringRef inBundleID
 - (void) setUp {
     [super setUp];
 
+    // Mock BGMDevice.
+    MockAudioObjects::CreateMockDevice(kBGMDeviceUID);
+    MockAudioObjects::CreateMockDevice(kBGMDeviceUID_UISounds);
+
     devices = [BGMMockAudioDeviceManager new];
     defaults = [BGMMockUserDefaults new];
     
@@ -137,9 +119,10 @@ void BGMMockBackgroundMusicDevice::SetMusicPlayerBundleID(CFStringRef inBundleID
 
 - (void) tearDown {
     [super tearDown];
+    MockAudioObjects::DestroyMocks();
 }
 
-- (void) testNoSelectedMusicPlayerStored {
+- (void) testNoSelectedMusicPlayerStored_iTunesDefault {
     // Test the case where the user has never changed the music player preference.
     
     // Test with iTunes as the default.
@@ -156,16 +139,20 @@ void BGMMockBackgroundMusicDevice::SetMusicPlayerBundleID(CFStringRef inBundleID
     
     XCTAssertEqualObjects(players.selectedMusicPlayer.musicPlayerID, [BGMiTunes sharedMusicPlayerID]);
     XCTAssertEqualObjects(players.selectedMusicPlayer.name, @"iTunes");
-    
-    [self resetDevice];
-    
+}
+
+
+- (void) testNoSelectedMusicPlayerStored_vlcDefault {
+    // Test the case where the user has never changed the music player preference.
+
     // Test with VLC as the default.
-    players = [[BGMMusicPlayers alloc] initWithAudioDevices:devices
-                                       defaultMusicPlayerID:vlcID
-                                         musicPlayerClasses:@[ BGMiTunes.class,
-                                                               BGMVLC.class,
-                                                               BGMDecibel.class ]
-                                               userDefaults:defaults];
+    BGMMusicPlayers* players =
+            [[BGMMusicPlayers alloc] initWithAudioDevices:devices
+                                     defaultMusicPlayerID:vlcID
+                                       musicPlayerClasses:@[ BGMiTunes.class,
+                                                             BGMVLC.class,
+                                                             BGMDecibel.class ]
+                                             userDefaults:defaults];
     
     XCTAssertEqual(players.musicPlayers.count, 3);
     
@@ -193,15 +180,15 @@ void BGMMockBackgroundMusicDevice::SetMusicPlayerBundleID(CFStringRef inBundleID
     
     XCTAssertEqualObjects(players.selectedMusicPlayer.musicPlayerID, spotifyID);
     XCTAssertEqualObjects(players.selectedMusicPlayer.name, @"Spotify");
-    
-    [self resetDevice];
-    
+}
+
+- (void) testUnrecognizedSelectedMusicPlayerInUserDefaults {
     // If there's an unrecognized ID in user defaults, the default music player should be selected.
     defaults.selectedPlayerID = [[NSUUID alloc] initWithUUIDString:@"11111111-1111-1111-0000-000000000000"];
     
     // This initializer sets iTunes as the default music player and adds all the other music players.
-    players = [[BGMMusicPlayers alloc] initWithAudioDevices:devices
-                                               userDefaults:defaults];
+    BGMMusicPlayers* players = [[BGMMusicPlayers alloc] initWithAudioDevices:devices
+                                                                userDefaults:defaults];
     
     XCTAssert(players.musicPlayers.count >= 6);
     
@@ -226,10 +213,5 @@ void BGMMockBackgroundMusicDevice::SetMusicPlayerBundleID(CFStringRef inBundleID
 
 // TODO: Test setting the selectedMusicPlayer property
 
-- (void) resetDevice {
-    // Reset the mock BGMDevice.
-    [devices bgmDevice].SetMusicPlayerBundleID(CFSTR(""));
-}
-
 @end
 

BGMApp/BGMAppTests/UnitTests/BGMPlayThroughRTLoggerTests.mm

@@ -0,0 +1,179 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  BGMPlayThroughRTLoggerTests.mm
+//  BGMAppUnitTests
+//
+//  Copyright © 2020 Kyle Neideck
+//
+
+// Unit Include
+#import "BGMPlayThroughRTLogger.h"
+
+// PublicUtility Includes
+#import "CARingBuffer.h"
+
+// System Includes
+#import <CoreAudio/CoreAudio.h>
+#import <XCTest/XCTest.h>
+
+
+@interface BGMPlayThroughRTLoggerTests : XCTestCase
+
+@end
+
+@implementation BGMPlayThroughRTLoggerTests
+{
+    BGMPlayThroughRTLogger* logger;
+}
+
+- (void) setUp {
+    [super setUp];
+    logger = new BGMPlayThroughRTLogger;
+}
+
+- (void) tearDown {
+    [super tearDown];
+    delete logger;
+}
+
+- (void) testLogReleasingWaitingThreads {
+    logger->LogReleasingWaitingThreads();
+    [self assertLoggedOneDebugMessage];
+}
+
+- (void) testLogIfMachError_ReleaseWaitingThreadsSignal {
+    logger->LogIfMachError_ReleaseWaitingThreadsSignal(KERN_SUCCESS);
+    [self assertLoggedNoMessages];
+}
+
+- (void) testLogIfDroppedFrames_didNotDropFrames {
+    logger->LogIfDroppedFrames(11256.0, 11256.0);
+    [self assertLoggedNoMessages];
+}
+
+- (void) testLogIfDroppedFrames_didDropFrames {
+    logger->LogIfDroppedFrames(11256.0, 11768.0);
+    [self assertLoggedOneDebugMessage];
+}
+
+- (void) testLogNoSamplesReady {
+    logger->LogNoSamplesReady(512, 1024, 512.0);
+    [self assertLoggedOneDebugMessage];
+}
+
+- (void) testLogExceptionStoppingIOProc_withoutErrorCode {
+    // Set a test-only flag that keeps it from calling abort() after logging the error when the
+    // tests are compiled with the debug configuration.
+    logger->mContinueOnErrorLogged = true;
+
+    logger->LogExceptionStoppingIOProc("InputDeviceIOProc");
+    [self assertLoggedOneErrorMessage];
+}
+
+- (void) testLogExceptionStoppingIOProc_withErrorCode {
+    // Set a test-only flag that keeps it from calling abort() after logging the error when the
+    // tests are compiled with the debug configuration.
+    logger->mContinueOnErrorLogged = true;
+
+    logger->LogExceptionStoppingIOProc("OutputDeviceIOProc", kAudioHardwareUnknownPropertyError);
+    [self assertLoggedOneErrorMessage];
+}
+
+- (void) testLogUnexpectedIOStateAfterStopping {
+    logger->LogUnexpectedIOStateAfterStopping("OutputDeviceIOProc", 1);
+    [self assertLoggedOneWarningMessage];
+}
+
+- (void) testLogRingBufferUnavailable {
+    logger->LogRingBufferUnavailable("OutputDeviceIOProc", false);
+    [self assertLoggedOneWarningMessage];
+}
+
+- (void) testLogIfRingBufferError_Fetch_noError {
+    logger->LogIfRingBufferError_Fetch(kCARingBufferError_OK);
+    [self assertLoggedNoMessages];
+}
+
+- (void) testLogIfRingBufferError_Fetch_errorCPUOverload {
+    logger->LogIfRingBufferError_Fetch(kCARingBufferError_CPUOverload);
+    [self assertLoggedOneWarningMessage];
+}
+
+- (void) testLogIfRingBufferError_Fetch_errorTooMuch {
+    // Set a test-only flag that keeps it from calling abort() after logging the error when the
+    // tests are compiled with the debug configuration.
+    logger->mContinueOnErrorLogged = true;
+
+    logger->LogIfRingBufferError_Fetch(kCARingBufferError_TooMuch);
+    [self assertLoggedOneErrorMessage];
+}
+
+- (void) testLogIfRingBufferError_Store_noError {
+    logger->LogIfRingBufferError_Store(kCARingBufferError_OK);
+    [self assertLoggedNoMessages];
+}
+
+- (void) testLogIfRingBufferError_Store_errorCPUOverload {
+    logger->LogIfRingBufferError_Store(kCARingBufferError_CPUOverload);
+    [self assertLoggedOneWarningMessage];
+}
+
+- (void) testLogIfRingBufferError_Store_errorTooMuch {
+    // Set a test-only flag that keeps it from calling abort() after logging the error when the
+    // tests are compiled with the debug configuration.
+    logger->mContinueOnErrorLogged = true;
+
+    logger->LogIfRingBufferError_Store(kCARingBufferError_TooMuch);
+    [self assertLoggedOneErrorMessage];
+}
+
+- (void) waitForLoggingThread {
+    // Wait for it to finish logging the messages.
+    bool noMessagesLeft = logger->WaitUntilLoggerThreadIdle();
+    XCTAssert(noMessagesLeft);
+}
+
+- (void) assertLoggedNoMessages {
+    [self waitForLoggingThread];
+    XCTAssertEqual(0, logger->mNumDebugMessagesLogged);
+    XCTAssertEqual(0, logger->mNumWarningMessagesLogged);
+    XCTAssertEqual(0, logger->mNumErrorMessagesLogged);
+}
+
+- (void) assertLoggedOneDebugMessage {
+    [self waitForLoggingThread];
+    XCTAssertEqual(1, logger->mNumDebugMessagesLogged);
+    XCTAssertEqual(0, logger->mNumWarningMessagesLogged);
+    XCTAssertEqual(0, logger->mNumErrorMessagesLogged);
+}
+
+- (void) assertLoggedOneWarningMessage {
+    [self waitForLoggingThread];
+    XCTAssertEqual(0, logger->mNumDebugMessagesLogged);
+    XCTAssertEqual(1, logger->mNumWarningMessagesLogged);
+    XCTAssertEqual(0, logger->mNumErrorMessagesLogged);
+}
+
+- (void) assertLoggedOneErrorMessage {
+    [self waitForLoggingThread];
+    XCTAssertEqual(0, logger->mNumDebugMessagesLogged);
+    XCTAssertEqual(0, logger->mNumWarningMessagesLogged);
+    XCTAssertEqual(1, logger->mNumErrorMessagesLogged);
+}
+
+@end
+

BGMApp/BGMAppTests/UnitTests/BGMPlayThroughTests.mm

@@ -0,0 +1,106 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  BGMPlayThroughTests.mm
+//  BGMAppUnitTests
+//
+//  Copyright © 2020 Kyle Neideck
+//
+
+// Unit Include
+#import "BGMPlayThrough.h"
+
+// Local Includes
+#import "MockAudioDevice.h"
+#import "MockAudioObjects.h"
+
+// BGM Includes
+#import "BGM_Types.h"
+#import "BGMAudioDevice.h"
+
+// STL Includes
+#import <memory>
+
+// System Includes
+#import <XCTest/XCTest.h>
+
+
+@interface BGMPlayThroughTests : XCTestCase
+
+@end
+
+@implementation BGMPlayThroughTests {
+    BGMAudioDevice inputDevice;
+    BGMAudioDevice outputDevice;
+
+    // The unit tests use mock implementations of CAHALAudioObject and CAHALAudioDevice, which are
+    // the superclasses of BGMAudioDevice. When BGMPlayThrough calls methods on inputDevice or
+    // outputDevice, some of them will update these objects.
+    std::shared_ptr<MockAudioDevice> mockInputDevice;
+    std::shared_ptr<MockAudioDevice> mockOutputDevice;
+}
+
+- (void) setUp {
+    [super setUp];
+
+    // Set up the mocks.
+    mockInputDevice = MockAudioObjects::CreateMockDevice(kBGMDeviceUID);
+    mockOutputDevice = MockAudioObjects::CreateMockDevice("Mock Output Device");
+
+    inputDevice = BGMAudioDevice(mockInputDevice->GetObjectID());
+    outputDevice = BGMAudioDevice(mockOutputDevice->GetObjectID());
+}
+
+- (void) tearDown {
+    [super tearDown];
+    MockAudioObjects::DestroyMocks();
+}
+
+- (void) testActivate {
+    // Set the mock output device's sample rate and IO buffer size.
+    outputDevice.SetNominalSampleRate(12345.0);
+    outputDevice.SetIOBufferSize(123);
+
+    // Create an instance and activate it.
+    BGMPlayThrough playThrough(inputDevice, outputDevice);
+    playThrough.Activate();
+
+    // It should set the input device's sample rate and IO buffer size to match the output device.
+    XCTAssertEqual(12345.0, inputDevice.GetNominalSampleRate());
+    XCTAssertEqual(123, inputDevice.GetIOBufferSize());
+
+    // It should add the property listeners it needs.
+    std::set<AudioObjectPropertySelector> expectedProperties {
+            kAudioDevicePropertyDeviceIsRunning,
+            kAudioDeviceProcessorOverload,
+            kAudioDeviceCustomPropertyDeviceIsRunningSomewhereOtherThanBGMApp
+    };
+
+    XCTAssertEqual(expectedProperties, mockInputDevice->mPropertiesWithListeners);
+}
+
+- (void) testDeactivate {
+    BGMPlayThrough playThrough(inputDevice, outputDevice);
+
+    playThrough.Activate();
+    playThrough.Deactivate();
+
+    // It should remove the property listeners added by Activate.
+    XCTAssert(mockInputDevice->mPropertiesWithListeners.empty());
+}
+
+@end
+

BGMApp/BGMAppTests/UnitTests/Mocks/MockAudioDevice.cpp

@@ -0,0 +1,61 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  MockAudioDevice.cpp
+//  BGMAppUnitTests
+//
+//  Copyright © 2020 Kyle Neideck
+//
+
+// Self Include
+#include "MockAudioDevice.h"
+
+// BGM Includes
+#include "BGM_Types.h"
+
+// STL Includes
+#include <functional>
+
+
+MockAudioDevice::MockAudioDevice(const std::string& inUID)
+:
+    mUID(inUID),
+    mNominalSampleRate(44100.0),
+    mIOBufferSize(512),
+    MockAudioObject(static_cast<AudioObjectID>(std::hash<std::string>{}(inUID)))
+{
+}
+
+CACFString MockAudioDevice::GetPlayerBundleID() const
+{
+    if(mUID != kBGMDeviceUID)
+    {
+        throw "Only BGMDevice has kAudioDeviceCustomPropertyMusicPlayerBundleID";
+    }
+
+    return mPlayerBundleID;
+}
+
+void MockAudioDevice::SetPlayerBundleID(const CACFString& inPlayerBundleID)
+{
+    if(mUID != kBGMDeviceUID)
+    {
+        throw "Only BGMDevice has kAudioDeviceCustomPropertyMusicPlayerBundleID";
+    }
+
+    mPlayerBundleID = inPlayerBundleID;
+}
+

BGMApp/BGMAppTests/UnitTests/Mocks/MockAudioDevice.h

@@ -0,0 +1,73 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  MockAudioObject.h
+//  BGMAppUnitTests
+//
+//  Copyright © 2020 Kyle Neideck
+//
+
+#ifndef BGMAppUnitTests__MockAudioDevice
+#define BGMAppUnitTests__MockAudioDevice
+
+// Superclass Includes
+#include "MockAudioObject.h"
+
+// STL Includes
+#include <string>
+
+
+/*!
+ * A mock audio device in our mock CoreAudio HAL. In the HAL's API class hierarchy, the base class
+ * for audio devices, kAudioDeviceClassID, is the audio objects class, kAudioObjectClassID.
+ *
+ * The unit tests generally use instances of this class to verify the HAL is being queried correctly
+ * and to control the responses that the code they're testing will receive from the mock HAL.
+ */
+class MockAudioDevice
+:
+        public MockAudioObject
+{
+
+public:
+    MockAudioDevice(const std::string& inUID);
+
+    /*!
+     * @return This device's music player bundle ID property.
+     * @throws If this device isn't a mock of BGMDevice.
+     */
+    CACFString GetPlayerBundleID() const;
+    /*!
+     * Set this device's music player bundle ID property.
+     * @throws If this device isn't a mock of BGMDevice.
+     */
+    void SetPlayerBundleID(const CACFString& inPlayerBundleID);
+
+    /*!
+     * The device's UID. The UID is a persistent token used to identify a particular audio device
+     * across boot sessions.
+     */
+    const std::string mUID;
+    Float64 mNominalSampleRate;
+    UInt32 mIOBufferSize;
+
+private:
+    CACFString mPlayerBundleID { "" };
+
+};
+
+#endif /* BGMAppUnitTests__MockAudioDevice */
+

BGMApp/BGMAppTests/UnitTests/Mocks/MockAudioObject.cpp

@@ -0,0 +1,37 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  MockAudioObject.cpp
+//  BGMAppUnitTests
+//
+//  Copyright © 2020 Kyle Neideck
+//
+
+// Self Include
+#include "MockAudioObject.h"
+
+
+MockAudioObject::MockAudioObject(AudioObjectID inAudioObjectID)
+:
+        mAudioObjectID(inAudioObjectID)
+{
+}
+
+AudioObjectID MockAudioObject::GetObjectID() const
+{
+    return mAudioObjectID;
+}
+

BGMApp/BGMAppTests/UnitTests/Mocks/MockAudioObject.h

@@ -0,0 +1,61 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  MockAudioObject.h
+//  BGMAppUnitTests
+//
+//  Copyright © 2020 Kyle Neideck
+//
+
+#ifndef BGMAppUnitTests__MockAudioObject
+#define BGMAppUnitTests__MockAudioObject
+
+// PublicUtility Includes
+#include "CACFString.h"
+
+// STL Includes
+#include <set>
+
+// System Includes
+#include <CoreAudio/CoreAudio.h>
+
+
+/*!
+ * The base class for mock audio objects in our mock CoreAudio HAL. Maps to kAudioObjectClassID
+ * (AudioHardwareBase.h) in the HAL's API class hierarchy.
+ */
+class MockAudioObject
+{
+
+public:
+    MockAudioObject(AudioObjectID inAudioObjectID);
+    virtual ~MockAudioObject() = default;
+
+    AudioObjectID GetObjectID() const;
+
+    /*!
+     * The properties that callers have added listeners for (and haven't since removed). See
+     * CAHALAudioObject::AddPropertyListener and CAHALAudioObject::RemovePropertyListener.
+     */
+    std::set<AudioObjectPropertySelector> mPropertiesWithListeners;
+
+private:
+    AudioObjectID mAudioObjectID;
+
+};
+
+#endif /* BGMAppUnitTests__MockAudioObject */
+

BGMApp/BGMAppTests/UnitTests/Mocks/MockAudioObjects.cpp

@@ -0,0 +1,123 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  MockAudioObjects.cpp
+//  BGMAppUnitTests
+//
+//  Copyright © 2020 Kyle Neideck
+//
+
+// Self Include
+#include "MockAudioObjects.h"
+
+// PublicUtility Includes
+#include "CACFString.h"
+
+
+// static
+MockAudioObjects::MockDeviceMap MockAudioObjects::sDevices;
+
+// static
+MockAudioObjects::MockDeviceMapByUID MockAudioObjects::sDevicesByUID;
+
+// static
+std::shared_ptr<MockAudioDevice> MockAudioObjects::CreateMockDevice(const std::string& inUID)
+{
+    std::shared_ptr<MockAudioDevice> mockDevice = std::make_shared<MockAudioDevice>(inUID);
+
+    sDevices.insert(MockDeviceMap::value_type(mockDevice->GetObjectID(), mockDevice));
+    sDevicesByUID.insert(MockDeviceMapByUID::value_type(inUID, mockDevice));
+
+    return mockDevice;
+}
+
+// static
+void MockAudioObjects::DestroyMocks()
+{
+    sDevices.clear();
+}
+
+// static
+std::shared_ptr<MockAudioObject> MockAudioObjects::GetAudioObject(AudioObjectID inAudioObjectID)
+{
+    auto device = GetAudioDeviceOrNull(inAudioObjectID);
+
+    if(device)
+    {
+        return device;
+    }
+
+    // Devices are the only audio objects we currently mock.
+
+    // Tests have to create mocks for all of the audio objects they expect the code they test to
+    // access. They should fail if it accesses any others.
+    throw "Mock audio object not found.";
+}
+
+// static
+std::shared_ptr<MockAudioDevice> MockAudioObjects::GetAudioDevice(AudioObjectID inAudioObjectID)
+{
+    auto device = GetAudioDeviceOrNull(inAudioObjectID);
+
+    if(device)
+    {
+        return device;
+    }
+
+    // Tests have to create mocks for all of the audio devices they expect the code they test to
+    // access. They should fail if it accesses any others.
+    throw "Mock audio device not found.";
+}
+
+// static
+std::shared_ptr<MockAudioDevice> MockAudioObjects::GetAudioDevice(CFStringRef inUID)
+{
+    // Convert inUID to a std::string.
+    UInt32 uidCStringLen = CACFString::GetStringByteLength(inUID) + 1;
+    char uidCString[uidCStringLen];
+    CACFString::GetCString(inUID, uidCString, uidCStringLen);
+    std::string uid = std::string(uidCString);
+
+    return GetAudioDevice(uid);
+}
+
+// static
+std::shared_ptr<MockAudioDevice> MockAudioObjects::GetAudioDevice(const std::string& inUID)
+{
+    auto device = sDevicesByUID.find(inUID);
+
+    if(device != sDevicesByUID.end())
+    {
+        return device->second;
+    }
+
+    return nullptr;
+}
+
+// static
+std::shared_ptr<MockAudioDevice>
+MockAudioObjects::GetAudioDeviceOrNull(AudioObjectID inAudioObjectID)
+{
+    auto device = sDevices.find(inAudioObjectID);
+
+    if(device != sDevices.end())
+    {
+        return device->second;
+    }
+
+    return nullptr;
+}
+

BGMApp/BGMAppTests/UnitTests/Mocks/MockAudioObjects.h

@@ -0,0 +1,90 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  MockAudioObjects.h
+//  BGMAppUnitTests
+//
+//  Copyright © 2020 Kyle Neideck
+//
+
+#ifndef BGMAppUnitTests__MockAudioObjects
+#define BGMAppUnitTests__MockAudioObjects
+
+// Local Includes
+#include "MockAudioObject.h"
+#include "MockAudioDevice.h"
+
+// STL Includes
+#include <map>
+#include <memory>
+#include <string>
+
+// System Includes
+#include <CoreAudio/CoreAudio.h>
+
+
+class MockAudioObjects
+{
+
+public:
+    /*!
+     * Create a mock audio device in the mock CoreAudio HAL.
+     *
+     * The mock device will then be accessible using GetAudioObject and GetAudioDevice. The
+     * Mock_CAHAL* implementations will access the mock device when they query the mock HAL.
+     *
+     * Unit tests can check the mock device to verify the code they're testing has called the mocked
+     * CAHAL classes correctly. They can also modify the mock device to control the Mock_CAHAL*
+     * implementations, e.g. to have CAHALAudioDevice::IsAlive return false so the test can cover
+     * the case where a device is being removed from the system.
+     *
+     * @param inUID The UID string to give the device. The UID is a persistent token used to
+     *              identify a particular audio device across boot sessions.
+     * @return The mock device.
+     */
+    static std::shared_ptr<MockAudioDevice> CreateMockDevice(const std::string& inUID);
+
+    /*!
+     * Remove all mock audio objects from the mock HAL. (Currently, mock devices are the only mock
+     * objects that can be created.)
+     */
+    static void DestroyMocks();
+
+    /*! Get a mock audio object by its ID. */
+    static std::shared_ptr<MockAudioObject> GetAudioObject(AudioObjectID inAudioObjectID);
+
+    /*! Get a mock audio device by its ID. */
+    static std::shared_ptr<MockAudioDevice> GetAudioDevice(AudioObjectID inAudioDeviceID);
+    /*! Get a mock audio device by its UID. */
+    static std::shared_ptr<MockAudioDevice> GetAudioDevice(const std::string& inUID);
+    /*! Get a mock audio device by its UID. */
+    static std::shared_ptr<MockAudioDevice> GetAudioDevice(CFStringRef inUID);
+
+private:
+    typedef std::map<AudioObjectID, std::shared_ptr<MockAudioDevice>> MockDeviceMap;
+    typedef std::map<std::string, std::shared_ptr<MockAudioDevice>> MockDeviceMapByUID;
+
+    static std::shared_ptr<MockAudioDevice> GetAudioDeviceOrNull(AudioObjectID inAudioDeviceID);
+
+    /*! Maps IDs to mocked audio devices. */
+    static MockDeviceMap sDevices;
+    /*! Maps UIDs (ID strings) to mocked audio devices. */
+    static MockDeviceMapByUID sDevicesByUID;
+
+};
+
+#endif /* BGMAppUnitTests__MockAudioObjects */
+

BGMApp/BGMAppTests/UnitTests/Mocks/Mock_CAHALAudioDevice.cpp

@@ -0,0 +1,691 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  Mock_CAHALAudioDevice.cpp
+//  BGMAppUnitTests
+//
+//  Copyright © 2020 Kyle Neideck
+//
+
+// Self Include
+#include "CAHALAudioDevice.h"
+
+// Local Includes
+#include "MockAudioDevice.h"
+#include "MockAudioObjects.h"
+
+// BGM Includes
+#include "BGM_Types.h"
+
+// PublicUtility Includes
+#include "CACFString.h"
+#include "CAHALAudioSystemObject.h"
+#include "CAPropertyAddress.h"
+
+
+#pragma clang diagnostic ignored "-Wunused-parameter"
+
+CAHALAudioDevice::CAHALAudioDevice(AudioObjectID inObjectID)
+:
+    CAHALAudioObject(inObjectID)
+{
+}
+
+CAHALAudioDevice::CAHALAudioDevice(CFStringRef inUID)
+:
+        CAHALAudioObject(CAHALAudioSystemObject().GetAudioDeviceForUID(inUID))
+{
+}
+
+CAHALAudioDevice::~CAHALAudioDevice()
+{
+}
+
+void	CAHALAudioDevice::GetCurrentVirtualFormats(bool inIsInput, UInt32& ioNumberStreams, AudioStreamBasicDescription* outFormats) const
+{
+    ioNumberStreams = 1;
+    CAPropertyAddress theAddress(kAudioStreamPropertyVirtualFormat);
+    UInt32 theSize = sizeof(AudioStreamBasicDescription);
+    GetPropertyData(theAddress, 0, NULL, theSize, outFormats);
+}
+
+UInt32	CAHALAudioDevice::GetIOBufferSize() const
+{
+    return MockAudioObjects::GetAudioDevice(GetObjectID())->mIOBufferSize;
+}
+
+void	CAHALAudioDevice::SetIOBufferSize(UInt32 inBufferSize)
+{
+    MockAudioObjects::GetAudioDevice(GetObjectID())->mIOBufferSize = inBufferSize;
+}
+
+bool	CAHALAudioDevice::IsAlive() const
+{
+    return true;
+}
+
+AudioDeviceIOProcID	CAHALAudioDevice::CreateIOProcID(AudioDeviceIOProc inIOProc, void* inClientData)
+{
+    return reinterpret_cast<AudioDeviceIOProcID>(0x99990000);
+}
+
+void	CAHALAudioDevice::DestroyIOProcID(AudioDeviceIOProcID inIOProcID)
+{
+}
+
+Float64	CAHALAudioDevice::GetNominalSampleRate() const
+{
+    return MockAudioObjects::GetAudioDevice(GetObjectID())->mNominalSampleRate;
+}
+
+void	CAHALAudioDevice::SetNominalSampleRate(Float64 inSampleRate)
+{
+    MockAudioObjects::GetAudioDevice(GetObjectID())->mNominalSampleRate = inSampleRate;
+}
+
+CFStringRef    CAHALAudioDevice::CopyDeviceUID() const
+{
+    std::string uid = MockAudioObjects::GetAudioDevice(GetObjectID())->mUID;
+    return CACFString(uid.c_str()).CopyCFString();
+}
+
+#pragma mark Unimplemented Methods
+
+bool	CAHALAudioDevice::HasModelUID() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+CFStringRef	CAHALAudioDevice::CopyModelUID() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+CFStringRef	CAHALAudioDevice::CopyConfigurationApplicationBundleID() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+CFURLRef	CAHALAudioDevice::CopyIconLocation() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetTransportType() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::CanBeDefaultDevice(bool inIsInput, bool inIsSystem) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::HasDevicePlugInStatus() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+OSStatus	CAHALAudioDevice::GetDevicePlugInStatus() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::IsHidden() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+pid_t	CAHALAudioDevice::GetHogModeOwner() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::IsHogModeSettable() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::TakeHogMode()
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::ReleaseHogMode()
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::HasPreferredStereoChannels(bool inIsInput) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::GetPreferredStereoChannels(bool inIsInput, UInt32& outLeft, UInt32& outRight) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::SetPreferredStereoChannels(bool inIsInput, UInt32 inLeft, UInt32 inRight)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::HasPreferredChannelLayout(bool inIsInput) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::GetPreferredChannelLayout(bool inIsInput, AudioChannelLayout& outChannelLayout) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::SetPreferredStereoChannels(bool inIsInput, AudioChannelLayout& inChannelLayout)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetNumberRelatedAudioDevices() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::GetRelatedAudioDevices(UInt32& ioNumberRelatedDevices, AudioObjectID* outRelatedDevices) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+AudioObjectID	CAHALAudioDevice::GetRelatedAudioDeviceByIndex(UInt32 inIndex) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetNumberStreams(bool inIsInput) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::GetStreams(bool inIsInput, UInt32& ioNumberStreams, AudioObjectID* outStreamList) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+AudioObjectID	CAHALAudioDevice::GetStreamByIndex(bool inIsInput, UInt32 inIndex) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetTotalNumberChannels(bool inIsInput) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::GetCurrentPhysicalFormats(bool inIsInput, UInt32& ioNumberStreams, AudioStreamBasicDescription* outFormats) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::IsRunning() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::IsRunningSomewhere() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetLatency(bool inIsInput) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetSafetyOffset(bool inIsInput) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::HasClockDomain() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetClockDomain() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+Float64	CAHALAudioDevice::GetActualSampleRate() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetNumberAvailableNominalSampleRateRanges() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::GetAvailableNominalSampleRateRanges(UInt32& ioNumberRanges, AudioValueRange* outRanges) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::GetAvailableNominalSampleRateRangeByIndex(UInt32 inIndex, Float64& outMinimum, Float64& outMaximum) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::IsValidNominalSampleRate(Float64 inSampleRate) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::IsIOBufferSizeSettable() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::UsesVariableIOBufferSizes() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetMaximumVariableIOBufferSize() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::HasIOBufferSizeRange() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::GetIOBufferSizeRange(UInt32& outMinimum, UInt32& outMaximum) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::StartIOProc(AudioDeviceIOProcID inIOProcID)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::StartIOProcAtTime(AudioDeviceIOProcID inIOProcID, AudioTimeStamp& ioStartTime, bool inIsInput, bool inIgnoreHardware)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::StopIOProc(AudioDeviceIOProcID inIOProcID)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::GetIOProcStreamUsage(AudioDeviceIOProcID inIOProcID, bool inIsInput, bool* outStreamUsage) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::SetIOProcStreamUsage(AudioDeviceIOProcID inIOProcID, bool inIsInput, const bool* inStreamUsage)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+Float32	CAHALAudioDevice::GetIOCycleUsage() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::SetIOCycleUsage(Float32 inValue)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::GetCurrentTime(AudioTimeStamp& outTime)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::TranslateTime(const AudioTimeStamp& inTime, AudioTimeStamp& outTime)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::GetNearestStartTime(AudioTimeStamp& ioTime, bool inIsInput, bool inIgnoreHardware)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::HasVolumeControl(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::VolumeControlIsSettable(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+Float32	CAHALAudioDevice::GetVolumeControlScalarValue(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+Float32	CAHALAudioDevice::GetVolumeControlDecibelValue(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::SetVolumeControlScalarValue(AudioObjectPropertyScope inScope, UInt32 inChannel, Float32 inValue)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::SetVolumeControlDecibelValue(AudioObjectPropertyScope inScope, UInt32 inChannel, Float32 inValue)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+Float32	CAHALAudioDevice::GetVolumeControlScalarForDecibelValue(AudioObjectPropertyScope inScope, UInt32 inChannel, Float32 inValue) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+Float32	CAHALAudioDevice::GetVolumeControlDecibelForScalarValue(AudioObjectPropertyScope inScope, UInt32 inChannel, Float32 inValue) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::HasSubVolumeControl(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::SubVolumeControlIsSettable(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+Float32	CAHALAudioDevice::GetSubVolumeControlScalarValue(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+Float32	CAHALAudioDevice::GetSubVolumeControlDecibelValue(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::SetSubVolumeControlScalarValue(AudioObjectPropertyScope inScope, UInt32 inChannel, Float32 inValue)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::SetSubVolumeControlDecibelValue(AudioObjectPropertyScope inScope, UInt32 inChannel, Float32 inValue)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+Float32	CAHALAudioDevice::GetSubVolumeControlScalarForDecibelValue(AudioObjectPropertyScope inScope, UInt32 inChannel, Float32 inValue) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+Float32	CAHALAudioDevice::GetSubVolumeControlDecibelForScalarValue(AudioObjectPropertyScope inScope, UInt32 inChannel, Float32 inValue) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::HasMuteControl(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::MuteControlIsSettable(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::GetMuteControlValue(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::SetMuteControlValue(AudioObjectPropertyScope inScope, UInt32 inChannel, bool inValue)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::HasSoloControl(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::SoloControlIsSettable(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::GetSoloControlValue(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::SetSoloControlValue(AudioObjectPropertyScope inScope, UInt32 inChannel, bool inValue)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::HasStereoPanControl(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::StereoPanControlIsSettable(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+Float32	CAHALAudioDevice::GetStereoPanControlValue(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::SetStereoPanControlValue(AudioObjectPropertyScope inScope, UInt32 inChannel, Float32 inValue)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::GetStereoPanControlChannels(AudioObjectPropertyScope inScope, UInt32 inChannel, UInt32& outLeftChannel, UInt32& outRightChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::HasJackControl(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::GetJackControlValue(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::HasSubMuteControl(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::SubMuteControlIsSettable(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::GetSubMuteControlValue(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::SetSubMuteControlValue(AudioObjectPropertyScope inScope, UInt32 inChannel, bool inValue)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::HasiSubOwnerControl(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::iSubOwnerControlIsSettable(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::GetiSubOwnerControlValue(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::SetiSubOwnerControlValue(AudioObjectPropertyScope inScope, UInt32 inChannel, bool inValue)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::HasDataSourceControl(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::DataSourceControlIsSettable(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetCurrentDataSourceID(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::SetCurrentDataSourceByID(AudioObjectPropertyScope inScope, UInt32 inChannel, UInt32 inID)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetNumberAvailableDataSources(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::GetAvailableDataSources(AudioObjectPropertyScope inScope, UInt32 inChannel, UInt32& ioNumberSources, UInt32* outSources) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetAvailableDataSourceByIndex(AudioObjectPropertyScope inScope, UInt32 inChannel, UInt32 inIndex) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+CFStringRef	CAHALAudioDevice::CopyDataSourceNameForID(AudioObjectPropertyScope inScope, UInt32 inChannel, UInt32 inID) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::HasDataDestinationControl(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::DataDestinationControlIsSettable(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetCurrentDataDestinationID(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::SetCurrentDataDestinationByID(AudioObjectPropertyScope inScope, UInt32 inChannel, UInt32 inID)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetNumberAvailableDataDestinations(AudioObjectPropertyScope inScope, UInt32 inChannel) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::GetAvailableDataDestinations(AudioObjectPropertyScope inScope, UInt32 inChannel, UInt32& ioNumberDestinations, UInt32* outDestinations) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetAvailableDataDestinationByIndex(AudioObjectPropertyScope inScope, UInt32 inChannel, UInt32 inIndex) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+CFStringRef	CAHALAudioDevice::CopyDataDestinationNameForID(AudioObjectPropertyScope inScope, UInt32 inChannel, UInt32 inID) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::HasClockSourceControl() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+bool	CAHALAudioDevice::ClockSourceControlIsSettable() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetCurrentClockSourceID() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::SetCurrentClockSourceByID(UInt32 inID)
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetNumberAvailableClockSources() const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+void	CAHALAudioDevice::GetAvailableClockSources(UInt32& ioNumberSources, UInt32* outSources) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetAvailableClockSourceByIndex(UInt32 inIndex) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+CFStringRef	CAHALAudioDevice::CopyClockSourceNameForID(UInt32 inID) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+
+UInt32	CAHALAudioDevice::GetClockSourceKindForID(UInt32 inID) const
+{
+    Throw(new CAException(kAudio_UnimplementedError));
+}
+

BGMApp/BGMAppTests/UnitTests/Mocks/Mock_CAHALAudioObject.cpp

@@ -17,25 +17,24 @@
 //  Mock_CAHALAudioObject.cpp
 //  BGMAppUnitTests
 //
-//  Copyright © 2016 Kyle Neideck
+//  Copyright © 2016, 2020 Kyle Neideck
 //
 
-// Self include
+// Self Include
 #include "CAHALAudioObject.h"
 
+// Local Includes
+#include "MockAudioObjects.h"
+
 // BGM Includes
 #include "BGM_Types.h"
 
-// System includes
-#include <CoreAudio/AudioHardware.h>
+// PublicUtility Includes
+#include "CACFString.h"
 
 
 #pragma clang diagnostic ignored "-Wunused-parameter"
 
-// The value of the music player bundle ID property. Tests should set this back to "" when they finish. (Has
-// to be static because we can't add to the real class's interface.)
-static CFStringRef playerBundleID = CFSTR("");
-
 CAHALAudioObject::CAHALAudioObject(AudioObjectID inObjectID)
 :
     mObjectID(inObjectID)
@@ -53,21 +52,89 @@ AudioObjectID	CAHALAudioObject::GetObjectID() const
 
 void	CAHALAudioObject::GetPropertyData(const AudioObjectPropertyAddress& inAddress, UInt32 inQualifierDataSize, const void* inQualifierData, UInt32& ioDataSize, void* outData) const
 {
-    if(inAddress.mSelector == kAudioDeviceCustomPropertyMusicPlayerBundleID)
+    switch(inAddress.mSelector)
     {
-        *reinterpret_cast<CFStringRef*>(outData) = playerBundleID;
+        case kAudioDeviceCustomPropertyMusicPlayerBundleID:
+            *reinterpret_cast<CFStringRef*>(outData) =
+                    MockAudioObjects::GetAudioDevice(GetObjectID())->
+                            GetPlayerBundleID().CopyCFString();
+            break;
+
+        case kAudioDevicePropertyStreams:
+            reinterpret_cast<AudioObjectID*>(outData)[0] = 1;
+            if(inAddress.mScope == kAudioObjectPropertyScopeGlobal)
+            {
+                reinterpret_cast<AudioObjectID*>(outData)[1] = 2;
+            }
+            break;
+
+        case kAudioDevicePropertyBufferFrameSize:
+            *reinterpret_cast<UInt32*>(outData) = 512;
+            break;
+
+        case kAudioDevicePropertyDeviceIsAlive:
+            *reinterpret_cast<UInt32*>(outData) = 1;
+            break;
+
+        case kAudioStreamPropertyVirtualFormat:
+        {
+            AudioStreamBasicDescription* outASBD =
+                    reinterpret_cast<AudioStreamBasicDescription*>(outData);
+            outASBD->mSampleRate = 44100.0;
+            outASBD->mFormatID = kAudioFormatLinearPCM;
+            outASBD->mFormatFlags =
+                    kAudioFormatFlagIsFloat | kAudioFormatFlagsNativeEndian | kAudioFormatFlagIsPacked;
+            outASBD->mBytesPerPacket = 8;
+            outASBD->mFramesPerPacket = 1;
+            outASBD->mBytesPerFrame = 8;
+            outASBD->mChannelsPerFrame = 2;
+            outASBD->mBitsPerChannel = 32;
+            break;
+        }
+
+        default:
+            Throw(new CAException(kAudio_UnimplementedError));
     }
 }
 
 void	CAHALAudioObject::SetPropertyData(const AudioObjectPropertyAddress& inAddress, UInt32 inQualifierDataSize, const void* inQualifierData, UInt32 inDataSize, const void* inData)
 {
-    if(inAddress.mSelector == kAudioDeviceCustomPropertyMusicPlayerBundleID)
+    switch(inAddress.mSelector)
     {
-        playerBundleID = *reinterpret_cast<const CFStringRef*>(inData);
+        case kAudioDeviceCustomPropertyMusicPlayerBundleID:
+            MockAudioObjects::GetAudioDevice(GetObjectID())->SetPlayerBundleID(
+                    CACFString(*reinterpret_cast<const CFStringRef*>(inData), false));
+            break;
+        default:
+            break;
     }
 }
 
-#pragma mark Unimplemented methods
+UInt32	CAHALAudioObject::GetPropertyDataSize(const AudioObjectPropertyAddress& inAddress, UInt32 inQualifierDataSize, const void* inQualifierData) const
+{
+    switch(inAddress.mSelector)
+    {
+        case kAudioDevicePropertyStreams:
+            return (inAddress.mScope == kAudioObjectPropertyScopeGlobal ? 2 : 1) *
+                    sizeof(AudioObjectID);
+        default:
+            Throw(new CAException(kAudio_UnimplementedError));
+    }
+}
+
+void	CAHALAudioObject::AddPropertyListener(const AudioObjectPropertyAddress& inAddress, AudioObjectPropertyListenerProc inListenerProc, void* inClientData)
+{
+    MockAudioObjects::GetAudioObject(GetObjectID())->
+            mPropertiesWithListeners.insert(inAddress.mSelector);
+}
+
+void	CAHALAudioObject::RemovePropertyListener(const AudioObjectPropertyAddress& inAddress, AudioObjectPropertyListenerProc inListenerProc, void* inClientData)
+{
+    MockAudioObjects::GetAudioObject(GetObjectID())->
+            mPropertiesWithListeners.erase(inAddress.mSelector);
+}
+
+#pragma mark Unimplemented Methods
 
 void	CAHALAudioObject::SetObjectID(AudioObjectID inObjectID)
 {
@@ -144,18 +211,3 @@ bool	CAHALAudioObject::IsPropertySettable(const AudioObjectPropertyAddress& inAd
     Throw(new CAException(kAudio_UnimplementedError));
 }
 
-UInt32	CAHALAudioObject::GetPropertyDataSize(const AudioObjectPropertyAddress& inAddress, UInt32 inQualifierDataSize, const void* inQualifierData) const
-{
-    Throw(new CAException(kAudio_UnimplementedError));
-}
-
-void	CAHALAudioObject::AddPropertyListener(const AudioObjectPropertyAddress& inAddress, AudioObjectPropertyListenerProc inListenerProc, void* inClientData)
-{
-    Throw(new CAException(kAudio_UnimplementedError));
-}
-
-void	CAHALAudioObject::RemovePropertyListener(const AudioObjectPropertyAddress& inAddress, AudioObjectPropertyListenerProc inListenerProc, void* inClientData)
-{
-    Throw(new CAException(kAudio_UnimplementedError));
-}
-

BGMApp/BGMAppTests/UnitTests/Mocks/Mock_CAHALAudioSystemObject.cpp

@@ -17,12 +17,18 @@
 //  Mock_CAHALAudioSystemObject.cpp
 //  BGMAppUnitTests
 //
-//  Copyright © 2017 Kyle Neideck
+//  Copyright © 2017, 2020 Kyle Neideck
 //
 
 // Self include
 #include "CAHALAudioSystemObject.h"
 
+// BGM Includes
+#include "BGM_Types.h"
+
+// Local Includes
+#include "MockAudioObjects.h"
+
 
 CAHALAudioSystemObject::CAHALAudioSystemObject()
 :
@@ -36,19 +42,17 @@ CAHALAudioSystemObject::~CAHALAudioSystemObject()
 
 AudioObjectID	CAHALAudioSystemObject::GetAudioDeviceForUID(CFStringRef inUID) const
 {
-    AudioObjectID id = kAudioObjectUnknown;
+    auto device = MockAudioObjects::GetAudioDevice(inUID);
 
-    // Generate a deterministic and random-ish ID from the UID string. Ideally we would ensure the
-    // IDs are unique, but this is probably fine.
-    for(int i = 0; i < CFStringGetLength(inUID); i++)
+    if(device)
     {
-        id += 37 * CFStringGetCharacterAtIndex(inUID, i);
+        return device->GetObjectID();
     }
 
-    return id;
+    return kAudioObjectUnknown;
 }
 
-#pragma mark Unimplemented methods
+#pragma mark Unimplemented Methods
 
 #pragma clang diagnostic ignored "-Wunused-parameter"
 

BGMApp/BGMThreadSafetyAnalysis.h

@@ -0,0 +1,383 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+// Original licence at the end of this file.
+
+//
+//  BGMThreadSafetyAnalysis.h
+//  PublicUtility
+//
+//  © Copyright 2007-2020, The Clang Team
+//  Copyright © 2020 Kyle Neideck
+//
+//  Macros that wrap Clang's attributes for statically checking concurrency properties. From
+//  <https://clang.llvm.org/docs/ThreadSafetyAnalysis.html#mutexheader>.
+//
+
+
+#ifndef PublicUtility__BGMThreadSafetyAnalysis
+#define PublicUtility__BGMThreadSafetyAnalysis
+
+// Enable thread safety attributes only with clang.
+// The attributes can be safely erased when compiling with other compilers.
+#if defined(__clang__) && (!defined(SWIG))
+#define THREAD_ANNOTATION_ATTRIBUTE__(x)   __attribute__((x))
+#else
+#define THREAD_ANNOTATION_ATTRIBUTE__(x)   // no-op
+#endif
+
+#define CAPABILITY(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(capability(x))
+
+#define SCOPED_CAPABILITY \
+  THREAD_ANNOTATION_ATTRIBUTE__(scoped_lockable)
+
+#define GUARDED_BY(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(guarded_by(x))
+
+#define PT_GUARDED_BY(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(pt_guarded_by(x))
+
+#define ACQUIRED_BEFORE(...) \
+  THREAD_ANNOTATION_ATTRIBUTE__(acquired_before(__VA_ARGS__))
+
+#define ACQUIRED_AFTER(...) \
+  THREAD_ANNOTATION_ATTRIBUTE__(acquired_after(__VA_ARGS__))
+
+#define REQUIRES(...) \
+  THREAD_ANNOTATION_ATTRIBUTE__(requires_capability(__VA_ARGS__))
+
+#define REQUIRES_SHARED(...) \
+  THREAD_ANNOTATION_ATTRIBUTE__(requires_shared_capability(__VA_ARGS__))
+
+#define ACQUIRE(...) \
+  THREAD_ANNOTATION_ATTRIBUTE__(acquire_capability(__VA_ARGS__))
+
+#define ACQUIRE_SHARED(...) \
+  THREAD_ANNOTATION_ATTRIBUTE__(acquire_shared_capability(__VA_ARGS__))
+
+#define RELEASE(...) \
+  THREAD_ANNOTATION_ATTRIBUTE__(release_capability(__VA_ARGS__))
+
+#define RELEASE_SHARED(...) \
+  THREAD_ANNOTATION_ATTRIBUTE__(release_shared_capability(__VA_ARGS__))
+
+#define TRY_ACQUIRE(...) \
+  THREAD_ANNOTATION_ATTRIBUTE__(try_acquire_capability(__VA_ARGS__))
+
+#define TRY_ACQUIRE_SHARED(...) \
+  THREAD_ANNOTATION_ATTRIBUTE__(try_acquire_shared_capability(__VA_ARGS__))
+
+#define EXCLUDES(...) \
+  THREAD_ANNOTATION_ATTRIBUTE__(locks_excluded(__VA_ARGS__))
+
+#define ASSERT_CAPABILITY(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(assert_capability(x))
+
+#define ASSERT_SHARED_CAPABILITY(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(assert_shared_capability(x))
+
+#define RETURN_CAPABILITY(x) \
+  THREAD_ANNOTATION_ATTRIBUTE__(lock_returned(x))
+
+#define NO_THREAD_SAFETY_ANALYSIS \
+  THREAD_ANNOTATION_ATTRIBUTE__(no_thread_safety_analysis)
+
+#endif /* PublicUtility__BGMThreadSafetyAnalysis */
+
+/*
+This file is derived from "mutex.h" from the Clang documentation at
+<https://clang.llvm.org/docs/ThreadSafetyAnalysis.html>. This is the original license of "mutex.h".
+
+==============================================================================
+The LLVM Project is under the Apache License v2.0 with LLVM Exceptions:
+==============================================================================
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+    TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+    1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
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+---- LLVM Exceptions to the Apache 2.0 License ----
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+
+In addition, if you combine or link compiled forms of this Software with
+software that is licensed under the GPLv2 ("Combined Software") and if a
+court of competent jurisdiction determines that the patent provision (Section
+3), the indemnity provision (Section 9) or other Section of the License
+conflicts with the conditions of the GPLv2, you may retroactively and
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+the License, but only in their entirety and only with respect to the Combined
+Software.
+
+==============================================================================
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+==============================================================================
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+terms. All such code will be identified clearly using at least one of two
+mechanisms:
+1) It will be in a separate directory tree with its own `LICENSE.txt` or
+   `LICENSE` file at the top containing the specific license and restrictions
+   which apply to that software, or
+2) It will contain specific license and restriction terms at the top of every
+   file.
+
+==============================================================================
+Legacy LLVM License (https://llvm.org/docs/DeveloperPolicy.html#legacy):
+==============================================================================
+University of Illinois/NCSA
+Open Source License
+
+Copyright (c) 2007-2019 University of Illinois at Urbana-Champaign.
+All rights reserved.
+
+Developed by:
+
+    LLVM Team
+
+    University of Illinois at Urbana-Champaign
+
+    http://llvm.org
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal with
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+    * Redistributions of source code must retain the above copyright notice,
+      this list of conditions and the following disclaimers.
+
+    * Redistributions in binary form must reproduce the above copyright notice,
+      this list of conditions and the following disclaimers in the
+      documentation and/or other materials provided with the distribution.
+
+    * Neither the names of the LLVM Team, University of Illinois at
+      Urbana-Champaign, nor the names of its contributors may be used to
+      endorse or promote products derived from this Software without specific
+      prior written permission.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
+SOFTWARE.
+ */
+

BGMApp/BGMXPCHelper/Info.plist

@@ -17,13 +17,13 @@
 	<key>CFBundlePackageType</key>
 	<string>XPC!</string>
 	<key>CFBundleShortVersionString</key>
-	<string>0.3.1</string>
+	<string>0.4.3</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
 	<string>1</string>
 	<key>NSHumanReadableCopyright</key>
-	<string>Copyright © 2016-2019 Background Music contributors</string>
+	<string>Copyright © 2016-2024 Background Music contributors</string>
 	<key>XPCService</key>
 	<dict>
 		<key>ServiceType</key>

BGMApp/BGMXPCHelper/post_install.sh

@@ -20,7 +20,7 @@
 # post_install.sh
 # BGMXPCHelper
 #
-# Copyright © 2016-2018 Kyle Neideck
+# Copyright © 2016-2020 Kyle Neideck
 #
 # Installs BGMXPCHelper's launchd plist file and "bootstraps" (registers/enables) it with launchd.
 #
@@ -68,7 +68,13 @@ fi
 # If DEPLOYMENT_POSTPROCESSING is true, xcodebuild calls this script even if you're just building
 # (and not also installing). I'm not sure why, as we have the "run script only when installing"
 # option enabled.
-if ! [[ -z ${ACTION} ]] && [[ "${ACTION}" != "install" ]]; then
+#
+# REAL_ACTION is a workaround for xcodebuild setting ACTION to "install" even if we're actually
+# making an archive.
+#
+# TODO: Archiving BGMXPCHelper from Xcode instead of using build_and_install.sh still fails.
+if ( ! [[ -z ${ACTION} ]] && [[ "${ACTION}" != "install" ]] ) || \
+        ( ! [[ -z ${REAL_ACTION} ]] && [[ "${REAL_ACTION}" == "archive" ]] ); then
     echo "$0 should only be called during an install. Exiting."
     exit 0
 fi

BGMApp/BGMXPCHelper/safe_install_dir.sh

@@ -71,7 +71,7 @@ check_dir() {
     pushd . > /dev/null
 
     # Normalize the path and follow symlinks.
-    REAL_PATH=$(python -c "import os,sys; print(os.path.realpath(sys.argv[1]))" "$1")
+    REAL_PATH=$(cd "$1" && pwd -P)
     cd "${REAL_PATH}"
 
     DIR_IS_SAFE=0
@@ -84,7 +84,7 @@ check_dir() {
         [[ $((0$(stat -f '%Lp' .) & 0022)) -eq 0 ]]; do
         # ...go upwards until we reach the root directory.
         cd ..
-        if [[ "${PWD}" == / ]]; then
+        if [[ "${PWD}" -ef / ]]; then
             DIR_IS_SAFE=1
             break
         fi

BGMApp/BGMXPCHelperTests/BGMXPCHelperTests.m

@@ -69,7 +69,7 @@
         dispatch_semaphore_signal(replySemaphore);
     } forUISoundsDevice:NO];
 
-    // Very long timeout to make it less likely to fail on Travis CI when there's high contention.
+    // Very long timeout to make it less likely to fail in CI builds when there's high contention.
     if (0 != dispatch_semaphore_wait(replySemaphore, dispatch_time(DISPATCH_TIME_NOW, 5 * 60 * NSEC_PER_SEC))) {
         XCTFail(@"Timed out waiting for BGMXPCHelper");
     }

BGMApp/PublicUtility/BGMDebugLogging.c

@@ -0,0 +1,50 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  BGMDebugLogging.c
+//  PublicUtility
+//
+//  Copyright © 2020, 2024 Kyle Neideck
+//
+
+// Self Include
+#include "BGMDebugLogging.h"
+
+
+#pragma clang assume_nonnull begin
+
+// It's probably not ideal to use a global variable for this, but it's a lot easier.
+#if DEBUG || CoreAudio_Debug
+    // Enable debug logging by default in debug builds.
+    int gDebugLoggingIsEnabled = 1;
+#else
+    int gDebugLoggingIsEnabled = 0;
+#endif
+
+// We don't bother synchronising accesses of gDebugLoggingIsEnabled because it isn't really
+// necessary and would complicate code that accesses it on realtime threads.
+int BGMDebugLoggingIsEnabled(void)
+{
+    return gDebugLoggingIsEnabled;
+}
+
+void BGMSetDebugLoggingEnabled(int inEnabled)
+{
+    gDebugLoggingIsEnabled = inEnabled;
+}
+
+#pragma clang assume_nonnull end
+

BGMApp/PublicUtility/BGMDebugLogging.h

@@ -0,0 +1,63 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  BGMDebugLogging.h
+//  PublicUtility
+//
+//  Copyright © 2020 Kyle Neideck
+//
+//  Functions to globally enable/disable debug logging, i.e. more detailed logging to help diagnose
+//  bugs. If debug logging is enabled, the DebugMsg macro from CADebugMacros.h (and possibly others)
+//  will log messages. If not, it won't do anything.
+//
+//  If the preprocessor macro CoreAudio_UseSysLog is true, which is currently the case for all build
+//  variants (see BGMApp/BGMApp.xcodeproj/project.pbxproj and
+//  BGMDriver/BGMDriver.xcodeproj/project.pbxproj), those messages will be logged using syslog and
+//  can be read using Console.app. Try searching for "background music", "bgm" or "coreaudiod".
+//
+//  Debug logging is enabled by default in debug builds, but in release builds you have to enable it
+//  by option-clicking the status bar icon and then checking the Debug Logging menu item. Enabling
+//  debug logging probably won't cause glitches, but we don't try to guarantee that and it's not
+//  well tested.
+//
+
+#ifndef PublicUtility__BGMDebugLogging
+#define PublicUtility__BGMDebugLogging
+
+#pragma clang assume_nonnull begin
+
+/*!
+ * @return Non-zero if debug logging is globally enabled. (Probably -- it's not synchronised.)
+ *         Real-time safe.
+ */
+#if defined(__cplusplus)
+extern "C"
+#endif
+int BGMDebugLoggingIsEnabled(void);
+
+/*!
+ * @param inEnabled Non-zero to globally enable debug logging, zero to disable it. The change might
+ *                  not be visible to other threads immediately.
+ */
+#if defined(__cplusplus)
+extern "C"
+#endif
+void BGMSetDebugLoggingEnabled(int inEnabled);
+
+#pragma clang assume_nonnull end
+
+#endif /* PublicUtility__BGMDebugLogging */
+

BGMApp/PublicUtility/CAAtomic.h

@@ -59,13 +59,15 @@ full barrier.
 #if TARGET_OS_WIN32
 	#include <windows.h>
 	#include <intrin.h>
-	#pragma intrinsic(_InterlockedOr)
+	#pragma intrinsic(_InterlockedOr)
 	#pragma intrinsic(_InterlockedAnd)
 #else
 	#include <CoreFoundation/CFBase.h>
 	#include <libkern/OSAtomic.h>
 #endif
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated"
 inline void CAMemoryBarrier() 
 {
 #if TARGET_OS_WIN32
@@ -196,6 +198,8 @@ inline bool CAAtomicTestAndSetBarrier(int bitToSet, void* theAddress)
 #endif
 }
 
+#pragma clang diagnostic pop
+
 // int32_t flavors -- for C++ only since we can't overload in C
 // CFBase.h defines SInt32 as signed int which is similar to int32_t. If CFBase.h is included, then
 // this will generate redefinition error. But on Mac, CFBase.h, still includes MacTypes.h where
@@ -243,6 +247,9 @@ inline int32_t CAAtomicDecrement32Barrier(volatile int32_t* theValue)
 }
 #endif // __cplusplus && !__LP64__
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated"
+
 #if __LP64__
 inline bool CAAtomicCompareAndSwap64Barrier( int64_t __oldValue, int64_t __newValue, volatile int64_t *__theValue )
 {
@@ -259,6 +266,8 @@ inline bool CAAtomicCompareAndSwapPtrBarrier(void *__oldValue, void *__newValue,
 #endif
 }
 
+#pragma clang diagnostic pop
+
 /* Spinlocks.  These use memory barriers as required to synchronize access to shared
  * memory protected by the lock.  The lock operation spins, but employs various strategies
  * to back off if the lock is held, making it immune to most priority-inversion livelocks.
@@ -273,6 +282,9 @@ bool    CASpinLockTry( volatile CASpinLock *__lock );
 void    CASpinLockLock( volatile CASpinLock *__lock );
 void    CASpinLockUnlock( volatile CASpinLock *__lock );
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated"
+
 inline void    CASpinLockLock( volatile CASpinLock *__lock )
 {
 #if TARGET_OS_MAC
@@ -301,5 +313,6 @@ inline bool    CASpinLockTry( volatile CASpinLock *__lock )
 #endif
 }
 
+#pragma clang diagnostic pop
 
 #endif // __CAAtomic_h__

BGMApp/PublicUtility/CADebugMacros.cpp

@@ -1,3 +1,28 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  CADebugMacros.cpp
+//  PublicUtility
+//
+//  Copyright (C) 2014 Apple Inc. All Rights Reserved.
+//  Copyright © 2016, 2017, 2020 Kyle Neideck
+//
+//  Original license header follows.
+//
+
 /*
      File: CADebugMacros.cpp
  Abstract: CADebugMacros.h
@@ -46,7 +71,6 @@
 */
 #include "CADebugMacros.h"
 #include <stdio.h>
-#include <stdarg.h>
 #if TARGET_API_MAC_OSX
 	#include <syslog.h>
 #endif
@@ -67,14 +91,12 @@ void	LogError(const char *fmt, ...)
 {
 	va_list args;
 	va_start(args, fmt);
-    // BGM edit: vprintf leaves args in an undefined state, which can cause a crash in
-    //           vsyslog. Also added CADebuggerStop(). Original code commented out below.
-//#if DEBUG
-//	vprintf(fmt, args);
-//#endif
-//#if TARGET_API_MAC_OSX
-//	vsyslog(LOG_ERR, fmt, args);
-//#endif
+    vLogError(fmt, args);
+    va_end(args);
+}
+
+void    vLogError(const char *fmt, va_list args)
+{
 #if (DEBUG || !TARGET_API_MAC_OSX) && !CoreAudio_UseSysLog
     printf("[ERROR] ");
     vprintf(fmt, args);
@@ -82,25 +104,22 @@ void	LogError(const char *fmt, ...)
 #else
     vsyslog(LOG_ERR, fmt, args);
 #endif
+
 #if DEBUG
     CADebuggerStop();
 #endif
-    // BGM edit end
-	va_end(args);
 }
 
 void	LogWarning(const char *fmt, ...)
 {
 	va_list args;
     va_start(args, fmt);
-    // BGM edit: vprintf leaves args in an undefined state, which can cause a crash in
-    //           vsyslog. Also added CADebuggerStop(). Original code commented out below.
-//#if DEBUG
-//	vprintf(fmt, args);
-//#endif
-//#if TARGET_API_MAC_OSX
-//	vsyslog(LOG_WARNING, fmt, args);
-//#endif
+    vLogWarning(fmt, args);
+    va_end(args);
+}
+
+void    vLogWarning(const char *fmt, va_list args)
+{
 #if (DEBUG || !TARGET_API_MAC_OSX) && !CoreAudio_UseSysLog
     printf("[WARNING] ");
     vprintf(fmt, args);
@@ -108,9 +127,8 @@ void	LogWarning(const char *fmt, ...)
 #else
     vsyslog(LOG_WARNING, fmt, args);
 #endif
+
 #if DEBUG
     //CADebuggerStop(); // TODO: Add a toggle for this to the project file (under "Preprocessor Macros"). Default to off.
 #endif
-    // BGM edit end
-	va_end(args);
 }

BGMApp/PublicUtility/CADebugMacros.h

@@ -1,3 +1,28 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  CADebugMacros.h
+//  PublicUtility
+//
+//  Copyright (C) 2014 Apple Inc. All Rights Reserved.
+//  Copyright © 2016, 2020 Kyle Neideck
+//
+//  Original license header follows.
+//
+
 /*
      File: CADebugMacros.h
  Abstract: Part of CoreAudio Utility Classes
@@ -57,6 +82,10 @@
 	#include "CoreAudioTypes.h"
 #endif
 
+#include "CADebugPrintf.h"
+
+#include <stdarg.h>
+
 //=============================================================================
 //	CADebugMacros
 //=============================================================================
@@ -92,42 +121,41 @@
 
 #pragma mark	Basic Definitions
 
+//	basic debugging print routines
+#if	TARGET_OS_MAC && !TARGET_API_MAC_CARBON
+	extern void DebugStr(const unsigned char* debuggerMsg);
+	#define	DebugMessage(msg)	DebugStr("\p"msg)
+	#define DebugMessageN1(msg, N1)
+	#define DebugMessageN2(msg, N1, N2)
+	#define DebugMessageN3(msg, N1, N2, N3)
+#else
+	#if	(CoreAudio_FlushDebugMessages && !CoreAudio_UseSysLog) || defined(CoreAudio_UseSideFile)
+		#define	FlushRtn	,fflush(DebugPrintfFile)
+	#else
+		#define	FlushRtn
+	#endif
+
+	#if		CoreAudio_ThreadStampMessages
+		#include <pthread.h>
+		#include "CAHostTimeBase.h"
+		#if TARGET_RT_64_BIT
+			#define	DebugPrintfThreadIDFormat	"%16p"
+		#else
+			#define	DebugPrintfThreadIDFormat	"%8p"
+		#endif
+		#define	DebugMsg(inFormat, ...)	DebugPrintf("%17qd: " DebugPrintfThreadIDFormat " " inFormat, CAHostTimeBase::GetCurrentTimeInNanos(), pthread_self(), ## __VA_ARGS__) FlushRtn
+	#elif	CoreAudio_TimeStampMessages
+		#include "CAHostTimeBase.h"
+		#define	DebugMsg(inFormat, ...)	DebugPrintf("%17qd: " inFormat, CAHostTimeBase::GetCurrentTimeInNanos(), ## __VA_ARGS__) FlushRtn
+	#else
+		#define	DebugMsg(inFormat, ...)	DebugPrintf(inFormat, ## __VA_ARGS__) FlushRtn
+	#endif
+#endif
+
 #if	DEBUG || CoreAudio_Debug
 	// can be used to break into debugger immediately, also see CADebugger
 	#define BusError()		{ long* p=NULL; *p=0; }
-	
-	//	basic debugging print routines
-	#if	TARGET_OS_MAC && !TARGET_API_MAC_CARBON
-		extern void DebugStr(const unsigned char* debuggerMsg);
-		#define	DebugMessage(msg)	DebugStr("\p"msg)
-		#define DebugMessageN1(msg, N1)
-		#define DebugMessageN2(msg, N1, N2)
-		#define DebugMessageN3(msg, N1, N2, N3)
-	#else
-		#include "CADebugPrintf.h"
-		
-		#if	(CoreAudio_FlushDebugMessages && !CoreAudio_UseSysLog) || defined(CoreAudio_UseSideFile)
-			#define	FlushRtn	,fflush(DebugPrintfFile)
-		#else
-			#define	FlushRtn
-		#endif
-		
-		#if		CoreAudio_ThreadStampMessages
-			#include <pthread.h>
-			#include "CAHostTimeBase.h"
-			#if TARGET_RT_64_BIT
-				#define	DebugPrintfThreadIDFormat	"%16p"
-			#else
-				#define	DebugPrintfThreadIDFormat	"%8p"
-			#endif
-			#define	DebugMsg(inFormat, ...)	DebugPrintf("%17qd: " DebugPrintfThreadIDFormat " " inFormat, CAHostTimeBase::GetCurrentTimeInNanos(), pthread_self(), ## __VA_ARGS__) FlushRtn
-		#elif	CoreAudio_TimeStampMessages
-			#include "CAHostTimeBase.h"
-			#define	DebugMsg(inFormat, ...)	DebugPrintf("%17qd: " inFormat, CAHostTimeBase::GetCurrentTimeInNanos(), ## __VA_ARGS__) FlushRtn
-		#else
-			#define	DebugMsg(inFormat, ...)	DebugPrintf(inFormat, ## __VA_ARGS__) FlushRtn
-		#endif
-	#endif
+
 	void	DebugPrint(const char *fmt, ...);	// can be used like printf
 	#ifndef DEBUGPRINT
 		#define DEBUGPRINT(msg) DebugPrint msg		// have to double-parenthesize arglist (see Debugging.h)
@@ -172,7 +200,7 @@
 	#endif
 
 #else
-	#define	DebugMsg(inFormat, ...)
+
 	#ifndef DEBUGPRINT
 		#define DEBUGPRINT(msg)
 	#endif
@@ -194,9 +222,11 @@
 #define DebugMessageN8(msg, N1, N2, N3, N4, N5, N6, N7, N8)		DebugMsg(msg, N1, N2, N3, N4, N5, N6, N7, N8)
 #define DebugMessageN9(msg, N1, N2, N3, N4, N5, N6, N7, N8, N9)	DebugMsg(msg, N1, N2, N3, N4, N5, N6, N7, N8, N9)
 
-// BGM edit: Added __printflike.
+// BGM edit: Added __printflike and va_list versions.
 void	LogError(const char *fmt, ...) __printflike(1, 2);			// writes to syslog (and stderr if debugging)
+void    vLogError(const char *fmt, va_list args);
 void	LogWarning(const char *fmt, ...) __printflike(1, 2);		// writes to syslog (and stderr if debugging)
+void    vLogWarning(const char *fmt, va_list args);
 
 #define	NO_ACTION	(void)0
 

BGMApp/PublicUtility/CADebugPrintf.cpp

@@ -1,3 +1,28 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  CADebugPrintf.cpp
+//  PublicUtility
+//
+//  Copyright (C) 2014 Apple Inc. All Rights Reserved.
+//  Copyright © 2020 Kyle Neideck
+//
+//  Original license header follows.
+//
+
 /*
      File: CADebugPrintf.cpp
  Abstract: CADebugPrintf.h
@@ -51,39 +76,39 @@
 //	Self Include
 #include "CADebugPrintf.h"
 
-#if	DEBUG || CoreAudio_Debug
-
-	#if	TARGET_OS_WIN32
-		#include <stdarg.h>
-		#include <stdio.h>
-		#include <Windows.h>
-		extern "C"
-		int	CAWin32DebugPrintf(char* inFormat, ...)
-		{
+#if	TARGET_OS_WIN32
+	#include <stdarg.h>
+	#include <stdio.h>
+	#include <Windows.h>
+	extern "C"
+	int	CAWin32DebugPrintf(char* inFormat, ...)
+	{
+		if (BGMDebugLoggingIsEnabled()) {
 			char theMessage[1024];
 			va_list theArguments;
 			va_start(theArguments, inFormat);
 			_vsnprintf(theMessage, 1024, inFormat, theArguments);
 			va_end(theArguments);
 			OutputDebugString(theMessage);
-			return 0;
 		}
-	#endif
-	
-	#if defined(CoreAudio_UseSideFile)
-		#include <unistd.h>
-		FILE* sDebugPrintfSideFile = NULL;
-		extern "C"
-		void OpenDebugPrintfSideFile()
-		{
-			if(sDebugPrintfSideFile == NULL)
-			{
-				char theFileName[1024];
-				snprintf(theFileName, sizeof(theFileName), CoreAudio_UseSideFile, getpid());
-				sDebugPrintfSideFile = fopen(theFileName, "a+");
-				DebugPrintfRtn(DebugPrintfFileComma "\n------------------------------\n");
-			}
-		}
-	#endif
 
+		return 0;
+	}
 #endif
+
+#if defined(CoreAudio_UseSideFile)
+	#include <unistd.h>
+	FILE* sDebugPrintfSideFile = NULL;
+	extern "C"
+	void OpenDebugPrintfSideFile()
+	{
+		if(sDebugPrintfSideFile == NULL)
+		{
+			char theFileName[1024];
+			snprintf(theFileName, sizeof(theFileName), CoreAudio_UseSideFile, getpid());
+			sDebugPrintfSideFile = fopen(theFileName, "a+");
+			DebugPrintfRtn(DebugPrintfFileComma "\n------------------------------\n");
+		}
+	}
+#endif
+

BGMApp/PublicUtility/CADebugPrintf.h

@@ -57,6 +57,8 @@
 	#include "CoreAudioTypes.h"
 #endif
 
+#include "BGMDebugLogging.h"
+
 //=============================================================================
 //	Macros to redirect debugging output to various logging services
 //=============================================================================
@@ -64,52 +66,48 @@
 //#define	CoreAudio_UseSysLog		1
 //#define	CoreAudio_UseSideFile	"/CoreAudio-%d.txt"
 
-#if	DEBUG || CoreAudio_Debug
-	
-	#if	TARGET_OS_WIN32
+#if	TARGET_OS_WIN32
+	#if defined(__cplusplus)
+	extern "C"
+	#endif
+	extern int CAWin32DebugPrintf(char* inFormat, ...);
+	#define	DebugPrintfRtn			CAWin32DebugPrintf
+	#define	DebugPrintfFile
+	#define	DebugPrintfLineEnding	"\n"
+	#define	DebugPrintfFileComma
+#else
+	#if	CoreAudio_UseSysLog
+		#include <sys/syslog.h>
+		#define	DebugPrintfRtn	syslog
+		#define	DebugPrintfFile	LOG_NOTICE
+		#define	DebugPrintfLineEnding	""
+		#define	DebugPrintfFileComma	DebugPrintfFile,
+	#elif defined(CoreAudio_UseSideFile)
+		#include <stdio.h>
 		#if defined(__cplusplus)
 		extern "C"
 		#endif
-		extern int CAWin32DebugPrintf(char* inFormat, ...);
-		#define	DebugPrintfRtn			CAWin32DebugPrintf
-		#define	DebugPrintfFile			
+		void OpenDebugPrintfSideFile();
+		extern FILE* sDebugPrintfSideFile;
+		#define	DebugPrintfRtn	fprintf
+		#define	DebugPrintfFile	((sDebugPrintfSideFile != NULL) ? sDebugPrintfSideFile : stderr)
 		#define	DebugPrintfLineEnding	"\n"
-		#define	DebugPrintfFileComma
+		#define	DebugPrintfFileComma	DebugPrintfFile,
 	#else
-		#if	CoreAudio_UseSysLog
-			#include <sys/syslog.h>
-			#define	DebugPrintfRtn	syslog
-			#define	DebugPrintfFile	LOG_NOTICE
-			#define	DebugPrintfLineEnding	""
-			#define	DebugPrintfFileComma	DebugPrintfFile,
-		#elif defined(CoreAudio_UseSideFile)
-			#include <stdio.h>
-			#if defined(__cplusplus)
-			extern "C"
-			#endif
-			void OpenDebugPrintfSideFile();
-			extern FILE* sDebugPrintfSideFile;
-			#define	DebugPrintfRtn	fprintf
-			#define	DebugPrintfFile	((sDebugPrintfSideFile != NULL) ? sDebugPrintfSideFile : stderr)
-			#define	DebugPrintfLineEnding	"\n"
-			#define	DebugPrintfFileComma	DebugPrintfFile,
-		#else
-			#include <stdio.h>
-			#define	DebugPrintfRtn	fprintf
-			#define	DebugPrintfFile	stderr
-			#define	DebugPrintfLineEnding	"\n"
-			#define	DebugPrintfFileComma	DebugPrintfFile,
-		#endif
+		#include <stdio.h>
+		#define	DebugPrintfRtn	fprintf
+		#define	DebugPrintfFile	stderr
+		#define	DebugPrintfLineEnding	"\n"
+		#define	DebugPrintfFileComma	DebugPrintfFile,
 	#endif
-
-	#define	DebugPrintf(inFormat, ...)	DebugPrintfRtn(DebugPrintfFileComma inFormat DebugPrintfLineEnding, ## __VA_ARGS__)
-#else
-	#define	DebugPrintfRtn	
-	#define	DebugPrintfFile	
-	#define	DebugPrintfLineEnding	
-	#define	DebugPrintfFileComma
-	#define	DebugPrintf(inFormat, ...)
 #endif
 
+#define DebugPrintf(inFormat, ...) \
+		do { \
+			if (BGMDebugLoggingIsEnabled()) { \
+                DebugPrintfRtn(DebugPrintfFileComma inFormat DebugPrintfLineEnding, ## __VA_ARGS__); \
+			} \
+		} while (0)
 
 #endif
+

BGMApp/PublicUtility/CAMutex.h

@@ -1,3 +1,28 @@
+// This file is part of Background Music.
+//
+// Background Music is free software: you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation, either version 2 of the
+// License, or (at your option) any later version.
+//
+// Background Music is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Background Music. If not, see <http://www.gnu.org/licenses/>.
+
+//
+//  CAMutex.h
+//  PublicUtility
+//
+//  Copyright (C) 2014 Apple Inc. All Rights Reserved.
+//  Copyright © 2020 Kyle Neideck
+//
+//  Original license header follows.
+//
+
 /*
      File: CAMutex.h
  Abstract: Part of CoreAudio Utility Classes
@@ -51,6 +76,8 @@
 //	Includes
 //==================================================================================================
 
+#include "BGMThreadSafetyAnalysis.h"
+
 //	System Includes
 #if !defined(__COREAUDIO_USE_FLAT_INCLUDES__)
 	#include <CoreAudio/CoreAudioTypes.h>
@@ -70,7 +97,7 @@
 //	A recursive mutex.
 //==================================================================================================
 
-class	CAMutex
+class CAPABILITY("mutex") CAMutex
 {
 //	Construction/Destruction
 public:
@@ -79,9 +106,9 @@ public:
 
 //	Actions
 public:
-	virtual bool	Lock();
-	virtual void	Unlock();
-	virtual bool	Try(bool& outWasLocked);	// returns true if lock is free, false if not
+	virtual bool	Lock() ACQUIRE();
+	virtual void	Unlock() RELEASE();
+	virtual bool	Try(bool& outWasLocked) TRY_ACQUIRE(true);	// returns true if lock is free, false if not
 	
 	virtual bool	IsFree() const;
 	virtual bool	IsOwnedByCurrentThread() const;
@@ -99,15 +126,15 @@ protected:
 
 //	Helper class to manage taking and releasing recursively
 public:
-	class			Locker
+	class SCOPED_CAPABILITY Locker
 	{
 	
 	//	Construction/Destruction
 	public:
-					Locker(CAMutex& inMutex) : mMutex(&inMutex), mNeedsRelease(false) { mNeedsRelease = mMutex->Lock(); }
-					Locker(CAMutex* inMutex) : mMutex(inMutex), mNeedsRelease(false) { mNeedsRelease = (mMutex != NULL && mMutex->Lock()); }
+					Locker(CAMutex& inMutex) ACQUIRE(inMutex) : mMutex(&inMutex), mNeedsRelease(false) { mNeedsRelease = mMutex->Lock(); }
+					Locker(CAMutex* inMutex) ACQUIRE(inMutex) : mMutex(inMutex), mNeedsRelease(false) { mNeedsRelease = (mMutex != NULL && mMutex->Lock()); }
 						// in this case the mutex can be null
-					~Locker() { if(mNeedsRelease) { mMutex->Unlock(); } }
+					~Locker() RELEASE() { if(mNeedsRelease) { mMutex->Unlock(); } }
 	
 	
 	private:
@@ -121,6 +148,8 @@ public:
 	
 	};
 
+	// Clang's static analysis doesn't work for unlocker classes. See
+	// <https://clang.llvm.org/docs/ThreadSafetyAnalysis.html#no-alias-analysis>.
 // Unlocker
 	class Unlocker
 	{
@@ -138,12 +167,12 @@ public:
 	};
 	
 // you can use this with Try - if you take the lock in try, pass in the outWasLocked var
-	class Tryer {
+	class SCOPED_CAPABILITY Tryer {
 	
 	//	Construction/Destruction
 	public:
-		Tryer (CAMutex &mutex) : mMutex(mutex), mNeedsRelease(false), mHasLock(false) { mHasLock = mMutex.Try (mNeedsRelease); }
-		~Tryer () { if (mNeedsRelease) mMutex.Unlock(); }
+		Tryer (CAMutex &mutex) TRY_ACQUIRE(true, mutex) : mMutex(mutex), mNeedsRelease(false), mHasLock(false) { mHasLock = mMutex.Try (mNeedsRelease); }
+		~Tryer () RELEASE() { if (mNeedsRelease) mMutex.Unlock(); }
 		
 		bool HasLock () const { return mHasLock; }
 

BGMApp/PublicUtility/CAPropertyAddress.h

@@ -98,29 +98,6 @@ public:
 	static bool			IsCongruentElement(AudioObjectPropertyElement inElement1, AudioObjectPropertyElement inElement2)									{ return (inElement1 == inElement2) || (inElement1 == kAudioObjectPropertyElementWildcard) || (inElement2 == kAudioObjectPropertyElementWildcard); }
 	static bool			IsCongruentAddress(const AudioObjectPropertyAddress& inAddress1, const AudioObjectPropertyAddress& inAddress2)						{ return IsCongruentScope(inAddress1.mScope, inAddress2.mScope) && IsCongruentSelector(inAddress1.mSelector, inAddress2.mSelector) && IsCongruentElement(inAddress1.mElement, inAddress2.mElement); }
 	static bool			IsCongruentLessThanAddress(const AudioObjectPropertyAddress& inAddress1, const AudioObjectPropertyAddress& inAddress2)				{ bool theAnswer = false; if(!IsCongruentScope(inAddress1.mScope, inAddress2.mScope)) { theAnswer = inAddress1.mScope < inAddress2.mScope; } else if(!IsCongruentSelector(inAddress1.mSelector, inAddress2.mSelector)) { theAnswer = inAddress1.mSelector < inAddress2.mSelector; } else if(!IsCongruentElement(inAddress1.mElement, inAddress2.mElement)) { theAnswer = inAddress1.mElement < inAddress2.mElement; } return theAnswer; }
-
-//  STL Helpers
-public:
-	struct EqualTo : public std::binary_function<AudioObjectPropertyAddress, AudioObjectPropertyAddress, bool>
-	{
-		bool	operator()(const AudioObjectPropertyAddress& inAddress1, const AudioObjectPropertyAddress& inAddress2) const								{ return IsSameAddress(inAddress1, inAddress2); }
-	};
-
-	struct LessThan : public std::binary_function<AudioObjectPropertyAddress, AudioObjectPropertyAddress, bool>
-	{
-		bool	operator()(const AudioObjectPropertyAddress& inAddress1, const AudioObjectPropertyAddress& inAddress2) const								{ return IsLessThanAddress(inAddress1, inAddress2); }
-	};
-
-	struct CongruentEqualTo : public std::binary_function<AudioObjectPropertyAddress, AudioObjectPropertyAddress, bool>
-	{
-		bool	operator()(const AudioObjectPropertyAddress& inAddress1, const AudioObjectPropertyAddress& inAddress2) const								{ return IsCongruentAddress(inAddress1, inAddress2); }
-	};
-
-	struct CongruentLessThan : public std::binary_function<AudioObjectPropertyAddress, AudioObjectPropertyAddress, bool>
-	{
-		bool	operator()(const AudioObjectPropertyAddress& inAddress1, const AudioObjectPropertyAddress& inAddress2) const								{ return IsCongruentLessThanAddress(inAddress1, inAddress2); }
-	};
-
 };
 
 //==================================================================================================
@@ -157,11 +134,8 @@ public:
 	const AudioObjectPropertyAddress*		GetItems() const																		{ return &(*mAddressList.begin()); }
 	AudioObjectPropertyAddress*				GetItems()																				{ return &(*mAddressList.begin()); }
 
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wdeprecated"
-	bool									HasItem(const AudioObjectPropertyAddress& inAddress) const								{ AddressList::const_iterator theIterator = std::find_if(mAddressList.begin(), mAddressList.end(), std::bind1st(CAPropertyAddress::CongruentEqualTo(), inAddress)); return theIterator != mAddressList.end(); }
-	bool									HasExactItem(const AudioObjectPropertyAddress& inAddress) const							{ AddressList::const_iterator theIterator = std::find_if(mAddressList.begin(), mAddressList.end(), std::bind1st(CAPropertyAddress::EqualTo(), inAddress)); return theIterator != mAddressList.end(); }
-#pragma clang diagnostic pop
+	bool									HasItem(const AudioObjectPropertyAddress& inAddress) const								{ AddressList::const_iterator theIterator = std::find_if(mAddressList.begin(), mAddressList.end(), [&inAddress](const CAPropertyAddress& addr) { return CAPropertyAddress::IsCongruentAddress(addr, inAddress); }); return theIterator != mAddressList.end(); }
+	bool									HasExactItem(const AudioObjectPropertyAddress& inAddress) const							{ AddressList::const_iterator theIterator = std::find_if(mAddressList.begin(), mAddressList.end(), [&inAddress](const CAPropertyAddress& addr) { return CAPropertyAddress::IsSameAddress(addr, inAddress); }); return theIterator != mAddressList.end(); }
 
 	void									AppendItem(const AudioObjectPropertyAddress& inAddress)									{ mAddressList.push_back(inAddress); }
 	void									AppendUniqueItem(const AudioObjectPropertyAddress& inAddress)							{ if(!HasItem(inAddress)) { mAddressList.push_back(inAddress); } }
@@ -169,7 +143,7 @@ public:
 	void									InsertItemAtIndex(UInt32 inIndex, const AudioObjectPropertyAddress& inAddress)			{ if(inIndex < mAddressList.size()) { AddressList::iterator theIterator = mAddressList.begin(); std::advance(theIterator, static_cast<int>(inIndex)); mAddressList.insert(theIterator, inAddress); } else { mAddressList.push_back(inAddress); } }
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wdeprecated"
-	void									EraseExactItem(const AudioObjectPropertyAddress& inAddress)								{ AddressList::iterator theIterator = std::find_if(mAddressList.begin(), mAddressList.end(), std::bind1st(CAPropertyAddress::EqualTo(), inAddress)); if(theIterator != mAddressList.end()) { mAddressList.erase(theIterator); } }
+	void									EraseExactItem(const AudioObjectPropertyAddress& inAddress)								{ AddressList::iterator theIterator = std::find_if(mAddressList.begin(), mAddressList.end(), [&inAddress](const CAPropertyAddress& addr) { return CAPropertyAddress::IsSameAddress(addr, inAddress); }); if(theIterator != mAddressList.end()) { mAddressList.erase(theIterator); } }
 #pragma clang diagnostic pop
 	void									EraseItemAtIndex(UInt32 inIndex)														{ if(inIndex < mAddressList.size()) { AddressList::iterator theIterator = mAddressList.begin(); std::advance(theIterator, static_cast<int>(inIndex)); mAddressList.erase(theIterator); } }
 	void									EraseAllItems()																			{ mAddressList.clear(); }

BGMApp/PublicUtility/CARingBuffer.h

@@ -87,13 +87,13 @@ public:
 							// Return false for failure (buffer not large enough).
 				
 	CARingBufferError	Fetch(AudioBufferList *abl, UInt32 nFrames, SampleTime frameNumber);
-								// will alter mNumDataBytes of the buffers
+								// will alter mDataByteSize of the buffers
 	
 	CARingBufferError	GetTimeBounds(SampleTime &startTime, SampleTime &endTime);
 	
 protected:
 
-	int						FrameOffset(SampleTime frameNumber) { return (frameNumber & mCapacityFramesMask) * mBytesPerFrame; }
+	UInt32					FrameOffset(SampleTime frameNumber) { return (frameNumber & mCapacityFramesMask) * mBytesPerFrame; }
 
 	CARingBufferError		ClipTimeBounds(SampleTime& startRead, SampleTime& endRead);
 	

BGMDriver/BGMDriver.xcodeproj/project.pbxproj

@@ -17,6 +17,7 @@
 		1C30A69F1C1E98F000C05AA5 /* CAMutex.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 1CB8B3841BBCEFE8000E2DD1 /* CAMutex.cpp */; };
 		1C38210E1C4A163A00A0C8C6 /* BGM_TaskQueue.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 1C38210C1C4A163A00A0C8C6 /* BGM_TaskQueue.cpp */; settings = {COMPILER_FLAGS = "-frandom-seed=BGMDriver-BGM_TaskQueue.cpp"; }; };
 		1C3DB4871BE063C500EC8160 /* BGM_DeviceTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 1C3DB4861BE063C500EC8160 /* BGM_DeviceTests.mm */; };
+		1C6181A72388FC8A0068C4D3 /* CARingBuffer.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 1C6181A52388FC8A0068C4D3 /* CARingBuffer.cpp */; };
 		1C7010751F05ED5100D8CCDC /* BGM_AudibleState.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 1C7010731F05ED5100D8CCDC /* BGM_AudibleState.cpp */; settings = {COMPILER_FLAGS = "-frandom-seed=BGMDriver-BGM_AudibleState.cpp"; }; };
 		1C7010761F05ED5100D8CCDC /* BGM_AudibleState.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 1C7010731F05ED5100D8CCDC /* BGM_AudibleState.cpp */; };
 		1C7010791F07A0BA00D8CCDC /* BGM_VolumeControl.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 1C7010771F07A0BA00D8CCDC /* BGM_VolumeControl.cpp */; settings = {COMPILER_FLAGS = "-frandom-seed=BGMDriver-BGM_VolumeControl.cpp"; }; };
@@ -43,6 +44,8 @@
 		1CD95B141E93AA5200EB8EF0 /* BGM_Stream.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 1CA2A9E01E8D1D08007A76A4 /* BGM_Stream.cpp */; };
 		1CDF3ABC1E863B980001E9B7 /* BGM_NullDevice.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 1CDF3ABA1E863B980001E9B7 /* BGM_NullDevice.cpp */; settings = {COMPILER_FLAGS = "-frandom-seed=BGMDriver-BGM_NullDevice.cpp"; }; };
 		1CDF3ABF1E8644C20001E9B7 /* BGM_AbstractDevice.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 1CDF3ABD1E8644C20001E9B7 /* BGM_AbstractDevice.cpp */; settings = {COMPILER_FLAGS = "-frandom-seed=BGMDriver-BGM_AbstractDevice.cpp"; }; };
+		1CE03A4B238A5BF40036908D /* CABitOperations.h in Headers */ = {isa = PBXBuildFile; fileRef = 1CE03A4A238A5BF40036908D /* CABitOperations.h */; };
+		1CE03A4C23928B370036908D /* CARingBuffer.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 1C6181A52388FC8A0068C4D3 /* CARingBuffer.cpp */; };
 		27379B821C76D62D0084A24C /* CADebugMacros.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 1CB8B3701BBBD8A4000E2DD1 /* CADebugMacros.cpp */; };
 		27379B831C76D62D0084A24C /* CADebugPrintf.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 1CB8B3781BBBDFA2000E2DD1 /* CADebugPrintf.cpp */; };
 		27381A161C8EF50F00DF167C /* BGM_XPCHelper.m in Sources */ = {isa = PBXBuildFile; fileRef = 27381A141C8EF50F00DF167C /* BGM_XPCHelper.m */; settings = {COMPILER_FLAGS = "-frandom-seed=BGMDriver-BGM_XPCHelper.m"; }; };
@@ -85,6 +88,7 @@
 		19FE7B8CE9148B3D8D7517C6 /* BGM_Control.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = BGM_Control.h; sourceTree = "<group>"; };
 		19FE7BC3396C4E50D21E1BC8 /* BGM_Control.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = BGM_Control.cpp; sourceTree = "<group>"; };
 		19FE7E6DC2A1B61211D74782 /* BGM_MuteControl.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = BGM_MuteControl.cpp; sourceTree = "<group>"; };
+		1C09150523F010E8001EB0E1 /* set-version.sh */ = {isa = PBXFileReference; lastKnownFileType = text.script.sh; path = "set-version.sh"; sourceTree = "<group>"; };
 		1C0CB6A61C4E06C00084C15A /* CAAtomicStack.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = CAAtomicStack.h; path = PublicUtility/CAAtomicStack.h; sourceTree = "<group>"; };
 		1C0CB6A71C4E06F70084C15A /* CAAtomic.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = CAAtomic.h; path = PublicUtility/CAAtomic.h; sourceTree = "<group>"; };
 		1C0CB6A91C50A3AF0084C15A /* CAAutoDisposer.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = CAAutoDisposer.h; path = PublicUtility/CAAutoDisposer.h; sourceTree = "<group>"; };
@@ -103,6 +107,8 @@
 		1C38210F1C4A18DE00A0C8C6 /* CAPThread.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = CAPThread.cpp; path = PublicUtility/CAPThread.cpp; sourceTree = "<group>"; };
 		1C3821101C4A18DE00A0C8C6 /* CAPThread.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = CAPThread.h; path = PublicUtility/CAPThread.h; sourceTree = "<group>"; };
 		1C3DB4861BE063C500EC8160 /* BGM_DeviceTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = BGM_DeviceTests.mm; sourceTree = "<group>"; };
+		1C6181A42388FC8A0068C4D3 /* CARingBuffer.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = CARingBuffer.h; path = PublicUtility/CARingBuffer.h; sourceTree = "<group>"; };
+		1C6181A52388FC8A0068C4D3 /* CARingBuffer.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = CARingBuffer.cpp; path = PublicUtility/CARingBuffer.cpp; sourceTree = "<group>"; };
 		1C7010731F05ED5100D8CCDC /* BGM_AudibleState.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = BGM_AudibleState.cpp; sourceTree = "<group>"; };
 		1C7010741F05ED5100D8CCDC /* BGM_AudibleState.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = BGM_AudibleState.h; sourceTree = "<group>"; };
 		1C7010771F07A0BA00D8CCDC /* BGM_VolumeControl.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = BGM_VolumeControl.cpp; sourceTree = "<group>"; };
@@ -149,6 +155,7 @@
 		1CDF3ABB1E863B980001E9B7 /* BGM_NullDevice.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = BGM_NullDevice.h; sourceTree = "<group>"; };
 		1CDF3ABD1E8644C20001E9B7 /* BGM_AbstractDevice.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = BGM_AbstractDevice.cpp; sourceTree = "<group>"; };
 		1CDF3ABE1E8644C20001E9B7 /* BGM_AbstractDevice.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = BGM_AbstractDevice.h; sourceTree = "<group>"; };
+		1CE03A4A238A5BF40036908D /* CABitOperations.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = CABitOperations.h; path = PublicUtility/CABitOperations.h; sourceTree = "<group>"; };
 		1CE3E68C1BE263CA00167F5D /* CACFDictionary.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = CACFDictionary.cpp; path = PublicUtility/CACFDictionary.cpp; sourceTree = "<group>"; };
 		1CE3E68D1BE263CA00167F5D /* CACFDictionary.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = CACFDictionary.h; path = PublicUtility/CACFDictionary.h; sourceTree = "<group>"; };
 		1CE3E68F1BE2683900167F5D /* CACFArray.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = CACFArray.cpp; path = PublicUtility/CACFArray.cpp; sourceTree = "<group>"; };
@@ -197,6 +204,15 @@
 /* End PBXFrameworksBuildPhase section */
 
 /* Begin PBXGroup section */
+		1C09150423F010E8001EB0E1 /* Scripts */ = {
+			isa = PBXGroup;
+			children = (
+				1C09150523F010E8001EB0E1 /* set-version.sh */,
+			);
+			name = Scripts;
+			path = ../SharedSource/Scripts;
+			sourceTree = "<group>";
+		};
 		1C0CB6AF1C642C600084C15A /* DeviceClients */ = {
 			isa = PBXGroup;
 			children = (
@@ -297,6 +313,7 @@
 				1C37B3681E9B8D3C000DF98F /* CAPropertyAddress.h */,
 				1C0CB6A61C4E06C00084C15A /* CAAtomicStack.h */,
 				1C0CB6A91C50A3AF0084C15A /* CAAutoDisposer.h */,
+				1CE03A4A238A5BF40036908D /* CABitOperations.h */,
 				1CE3E68F1BE2683900167F5D /* CACFArray.cpp */,
 				1CE3E6901BE2683900167F5D /* CACFArray.h */,
 				1CE3E68C1BE263CA00167F5D /* CACFDictionary.cpp */,
@@ -320,6 +337,8 @@
 				1CB8B3851BBCEFE8000E2DD1 /* CAMutex.h */,
 				1C38210F1C4A18DE00A0C8C6 /* CAPThread.cpp */,
 				1C3821101C4A18DE00A0C8C6 /* CAPThread.h */,
+				1C6181A42388FC8A0068C4D3 /* CARingBuffer.h */,
+				1C6181A52388FC8A0068C4D3 /* CARingBuffer.cpp */,
 				1CB8B38C1BBCF4A9000E2DD1 /* CAVolumeCurve.cpp */,
 				1CB8B38D1BBCF4A9000E2DD1 /* CAVolumeCurve.h */,
 			);
@@ -343,6 +362,7 @@
 				27D643B71C9FABF600737F6E /* BGM_Types.h */,
 				2771700E1CA0C16200AB34B4 /* BGM_Utils.h */,
 				275343BC1DE9B44900DF3858 /* BGM_Utils.cpp */,
+				1C09150423F010E8001EB0E1 /* Scripts */,
 				27D643C21C9FBC5800737F6E /* BGM_TestUtils.h */,
 				27D643B81C9FABF600737F6E /* BGMXPCProtocols.h */,
 			);
@@ -356,6 +376,7 @@
 			isa = PBXHeadersBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				1CE03A4B238A5BF40036908D /* CABitOperations.h in Headers */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -386,6 +407,7 @@
 				1CB8B3601BBBB78D000E2DD1 /* Sources */,
 				1CB8B3611BBBB78D000E2DD1 /* Frameworks */,
 				1CB8B3621BBBB78D000E2DD1 /* Resources */,
+				1C09150823F01E6D001EB0E1 /* Run Script - set-version.sh */,
 			);
 			buildRules = (
 			);
@@ -437,11 +459,11 @@
 			};
 			buildConfigurationList = 1CB8B35D1BBBB69C000E2DD1 /* Build configuration list for PBXProject "BGMDriver" */;
 			compatibilityVersion = "Xcode 6.3";
-			developmentRegion = English;
+			developmentRegion = en;
 			hasScannedForEncodings = 0;
 			knownRegions = (
-				English,
 				en,
+				Base,
 			);
 			mainGroup = 1CB8B3591BBBB69C000E2DD1;
 			productRefGroup = 1CB8B3651BBBB78D000E2DD1 /* Products */;
@@ -473,11 +495,33 @@
 		};
 /* End PBXResourcesBuildPhase section */
 
+/* Begin PBXShellScriptBuildPhase section */
+		1C09150823F01E6D001EB0E1 /* Run Script - set-version.sh */ = {
+			isa = PBXShellScriptBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			inputFileListPaths = (
+			);
+			inputPaths = (
+			);
+			name = "Run Script - set-version.sh";
+			outputFileListPaths = (
+			);
+			outputPaths = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+			shellPath = /bin/sh;
+			shellScript = "# Append the git HEAD short ID to the build version for SNAPSHOT and DEBUG builds.\n\"$SRCROOT/../SharedSource/Scripts/set-version.sh\"\n";
+		};
+/* End PBXShellScriptBuildPhase section */
+
 /* Begin PBXSourcesBuildPhase section */
 		1C8034D61BDD073B00668E00 /* Sources */ = {
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				1CE03A4C23928B370036908D /* CARingBuffer.cpp in Sources */,
 				1CD95B121E93AA5200EB8EF0 /* BGM_AbstractDevice.cpp in Sources */,
 				1CD95B131E93AA5200EB8EF0 /* BGM_NullDevice.cpp in Sources */,
 				1CD95B141E93AA5200EB8EF0 /* BGM_Stream.cpp in Sources */,
@@ -546,6 +590,7 @@
 				2743C9CD1D7EF8760089613B /* CACFArray.cpp in Sources */,
 				2743C9CF1D7EF8760089613B /* CACFDictionary.cpp in Sources */,
 				2743C9D11D7EF8760089613B /* CACFNumber.cpp in Sources */,
+				1C6181A72388FC8A0068C4D3 /* CARingBuffer.cpp in Sources */,
 				2743C9D31D7EF8760089613B /* CACFString.cpp in Sources */,
 				2743C9D51D7EF8760089613B /* CADebugger.cpp in Sources */,
 				2743C9D71D7EF8760089613B /* CADebugMacros.cpp in Sources */,
@@ -627,6 +672,7 @@
 				CLANG_WARN_NULLABLE_TO_NONNULL_CONVERSION = YES;
 				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
 				CLANG_WARN_OBJC_REPEATED_USE_OF_WEAK = YES;
+				CLANG_WARN_QUOTED_INCLUDE_IN_FRAMEWORK_HEADER = YES;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
 				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_IMPLICIT_CONVERSION = YES;
@@ -666,7 +712,7 @@
 				GCC_WARN_UNUSED_LABEL = YES;
 				GCC_WARN_UNUSED_PARAMETER = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				MACOSX_DEPLOYMENT_TARGET = 10.9;
+				MACOSX_DEPLOYMENT_TARGET = 10.13;
 				ONLY_ACTIVE_ARCH = YES;
 				RUN_CLANG_STATIC_ANALYZER = YES;
 				WARNING_CFLAGS = "-Wpartial-availability";
@@ -694,6 +740,7 @@
 				CLANG_WARN_NULLABLE_TO_NONNULL_CONVERSION = YES;
 				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
 				CLANG_WARN_OBJC_REPEATED_USE_OF_WEAK = YES;
+				CLANG_WARN_QUOTED_INCLUDE_IN_FRAMEWORK_HEADER = YES;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
 				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_IMPLICIT_CONVERSION = YES;
@@ -733,7 +780,7 @@
 				GCC_WARN_UNUSED_LABEL = YES;
 				GCC_WARN_UNUSED_PARAMETER = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				MACOSX_DEPLOYMENT_TARGET = 10.9;
+				MACOSX_DEPLOYMENT_TARGET = 10.13;
 				RUN_CLANG_STATIC_ANALYZER = YES;
 				WARNING_CFLAGS = "-Wpartial-availability";
 			};
@@ -762,13 +809,14 @@
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
 				INFOPLIST_FILE = BGMDriver/Info.plist;
+				INSTALL_GROUP = wheel;
+				INSTALL_OWNER = root;
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Audio/Plug-Ins/HAL";
 				MTL_ENABLE_DEBUG_INFO = YES;
 				ONLY_ACTIVE_ARCH = YES;
 				PRODUCT_BUNDLE_IDENTIFIER = com.bearisdriving.BGM.Driver;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SDKROOT = macosx;
-				SKIP_INSTALL = NO;
 				WRAPPER_EXTENSION = driver;
 			};
 			name = Debug;
@@ -797,12 +845,13 @@
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
 				INFOPLIST_FILE = BGMDriver/Info.plist;
+				INSTALL_GROUP = wheel;
+				INSTALL_OWNER = root;
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Audio/Plug-Ins/HAL";
 				MTL_ENABLE_DEBUG_INFO = NO;
 				PRODUCT_BUNDLE_IDENTIFIER = com.bearisdriving.BGM.Driver;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SDKROOT = macosx;
-				SKIP_INSTALL = NO;
 				WRAPPER_EXTENSION = driver;
 			};
 			name = Release;
@@ -833,6 +882,7 @@
 				MTL_ENABLE_DEBUG_INFO = YES;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SDKROOT = macosx;
+				SKIP_INSTALL = YES;
 			};
 			name = Debug;
 		};
@@ -857,6 +907,7 @@
 				MTL_ENABLE_DEBUG_INFO = NO;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SDKROOT = macosx;
+				SKIP_INSTALL = YES;
 			};
 			name = Release;
 		};

BGMDriver/BGMDriver.xcodeproj/xcshareddata/xcschemes/Background Music Device.xcscheme

@@ -26,21 +26,12 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES"
       enableAddressSanitizer = "YES"
-      language = ""
-      shouldUseLaunchSchemeArgsEnv = "YES">
-      <Testables>
-         <TestableReference
-            skipped = "NO">
-            <BuildableReference
-               BuildableIdentifier = "primary"
-               BlueprintIdentifier = "1C8034D91BDD073B00668E00"
-               BuildableName = "BGMDriverTests.xctest"
-               BlueprintName = "BGMDriverTests"
-               ReferencedContainer = "container:BGMDriver.xcodeproj">
-            </BuildableReference>
-         </TestableReference>
-      </Testables>
+      enableASanStackUseAfterReturn = "YES"
+      enableUBSanitizer = "YES"
+      codeCoverageEnabled = "YES"
+      onlyGenerateCoverageForSpecifiedTargets = "YES">
       <MacroExpansion>
          <BuildableReference
             BuildableIdentifier = "primary"
@@ -50,15 +41,37 @@
             ReferencedContainer = "container:BGMDriver.xcodeproj">
          </BuildableReference>
       </MacroExpansion>
-      <AdditionalOptions>
-      </AdditionalOptions>
+      <CodeCoverageTargets>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "1CB8B3631BBBB78D000E2DD1"
+            BuildableName = "Background Music Device.driver"
+            BlueprintName = "Background Music Device"
+            ReferencedContainer = "container:BGMDriver.xcodeproj">
+         </BuildableReference>
+      </CodeCoverageTargets>
+      <Testables>
+         <TestableReference
+            skipped = "NO"
+            parallelizable = "YES"
+            testExecutionOrdering = "random">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "1C8034D91BDD073B00668E00"
+               BuildableName = "BGMDriverTests.xctest"
+               BlueprintName = "BGMDriverTests"
+               ReferencedContainer = "container:BGMDriver.xcodeproj">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
    </TestAction>
    <LaunchAction
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       debugAsWhichUser = "root"
-      language = ""
+      enableASanStackUseAfterReturn = "YES"
+      disableMainThreadChecker = "YES"
       launchStyle = "1"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
@@ -85,8 +98,6 @@
             isEnabled = "YES">
          </EnvironmentVariable>
       </EnvironmentVariables>
-      <AdditionalOptions>
-      </AdditionalOptions>
    </LaunchAction>
    <ProfileAction
       buildConfiguration = "Release"

BGMDriver/BGMDriver.xcodeproj/xcshareddata/xcschemes/PublicUtility.xcscheme

@@ -26,19 +26,20 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES"
       enableAddressSanitizer = "YES"
-      language = ""
-      shouldUseLaunchSchemeArgsEnv = "YES">
+      enableASanStackUseAfterReturn = "YES"
+      enableUBSanitizer = "YES"
+      disableMainThreadChecker = "YES">
       <Testables>
       </Testables>
-      <AdditionalOptions>
-      </AdditionalOptions>
    </TestAction>
    <LaunchAction
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
+      enableASanStackUseAfterReturn = "YES"
+      disableMainThreadChecker = "YES"
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
@@ -61,8 +62,6 @@
             isEnabled = "YES">
          </EnvironmentVariable>
       </EnvironmentVariables>
-      <AdditionalOptions>
-      </AdditionalOptions>
    </LaunchAction>
    <ProfileAction
       buildConfiguration = "Release"

BGMDriver/BGMDriver/BGM_AbstractDevice.cpp

@@ -18,7 +18,7 @@
 //  BGMDriver
 //
 //  Copyright © 2017 Kyle Neideck
-//  Portions copyright (C) 2013 Apple Inc. All Rights Reserved.
+//  Copyright (C) 2013 Apple Inc. All Rights Reserved.
 //
 
 // Self Include

BGMDriver/BGMDriver/BGM_AudibleState.cpp

@@ -175,7 +175,7 @@ bool    BGM_AudibleState::BufferIsAudible(UInt32 inIOBufferFrameSize, const Floa
     // Check each frame to see if any are audible. This could be much more accurate, but seems to
     // work well enough for now.
     //
-    // The trade off here is between pausing the music player at the wrong time and unpausing it at
+    // The trade-off here is between pausing the music player at the wrong time and unpausing it at
     // the wrong time. If a short sound (e.g. a UI alert) plays but has a long, barely-audible tail,
     // we might not detect the silence quickly enough and pause the music player. Similarly, if
     // we've paused the music player and there's a period of near-silence in the new audio, we might

BGMDriver/BGMDriver/BGM_Control.cpp

@@ -18,7 +18,7 @@
 //  BGMDriver
 //
 //  Copyright © 2017 Kyle Neideck
-//  Portions copyright (C) 2013 Apple Inc. All Rights Reserved.
+//  Copyright (C) 2013 Apple Inc. All Rights Reserved.
 //
 
 // Self Include

BGMDriver/BGMDriver/BGM_Device.cpp

@@ -17,9 +17,11 @@
 //  BGM_Device.cpp
 //  BGMDriver
 //
-//  Copyright © 2016, 2017 Kyle Neideck
+//  Copyright © 2016, 2017, 2019 Kyle Neideck
 //  Copyright © 2017 Andrew Tonner
-//  Portions copyright (C) 2013 Apple Inc. All Rights Reserved.
+//  Copyright © 2019 Gordon Childs
+//  Copyright © 2020 Aleksey Yurkevich
+//  Copyright (C) 2013 Apple Inc. All Rights Reserved.
 //
 //  Based largely on SA_Device.cpp from Apple's SimpleAudioDriver Plug-In sample code. Also uses a few sections from Apple's
 //  NullAudio.c sample code (found in the same sample project).
@@ -199,9 +201,11 @@ void    BGM_Device::InitLoopback()
     // Calculate the number of host clock ticks per frame for our loopback clock.
     mLoopbackTime.hostTicksPerFrame = CAHostTimeBase::GetFrequency() / mLoopbackSampleRate;
     
-    //  Zero-out the loopback buffer
+    //  Allocate (or re-allocate) the loopback buffer.
     //  2 channels * 32-bit float = bytes in each frame
-    memset(mLoopbackRingBuffer, 0, sizeof(Float32) * 2 * kLoopbackRingBufferFrameSize);
+    //  Pass 1 for nChannels because it's going to be storing interleaved audio, which means we
+    //  don't need a separate buffer for each channel.
+	mLoopbackRingBuffer.Allocate(1, 2 * sizeof(Float32), kLoopbackRingBufferFrameSize);
 }
 
 #pragma mark Property Operations
@@ -1203,6 +1207,7 @@ void	BGM_Device::StartIO(UInt32 inClientID)
     // frames or increase latency.
     if(!clientIsBGMApp && bgmAppHasClientRegistered)
     {
+        DebugMsg("BGM_Device::StartIO: StartBGMAppPlayThroughSync.");
         UInt64 theXPCError = StartBGMAppPlayThroughSync(GetObjectID() == kObjectID_Device_UI_Sounds);
         
         switch(theXPCError)
@@ -1214,9 +1219,15 @@ void	BGM_Device::StartIO(UInt32 inClientID)
             case kBGMXPC_MessageFailure:
                 // This most likely means BGMXPCHelper isn't installed or has crashed. IO will probably still work,
                 // but we may drop frames while the audio hardware starts up.
-                LogError("BGM_Device::StartIO: Couldn't reach BGMApp via XPC. Attempting to start IO anyway.");
+                LogWarning("BGM_Device::StartIO: Couldn't reach BGMApp via XPC. Attempting to start IO anyway.");
                 break;
-                
+                       
+           case kBGMXPC_Timeout:
+               // XPC timeout. IO will probably still work,
+               // but we may drop frames while the audio hardware starts up.
+               LogWarning("BGM_Device::StartIO: Couldn't reach BGMApp via XPC (timeout). Attempting to start IO anyway.");
+               break;
+
             case kBGMXPC_ReturningEarlyError:
                 // This can (and might always) happen when the user changes output device in BGMApp while IO is running.
                 // See BGMAudioDeviceManager::startPlayThroughSync and BGMPlayThrough::WaitForOutputDeviceToStart.
@@ -1224,8 +1235,9 @@ void	BGM_Device::StartIO(UInt32 inClientID)
                 break;
                 
             default:
+                DebugMsg("BGM_Device::StartIO: BGMApp failed to start the output device. theXPCError=%llu", theXPCError);
                 LogError("BGM_Device::StartIO: BGMApp failed to start the output device. theXPCError=%llu", theXPCError);
-                Throw(CAException(kAudioHardwareNotRunningError));
+                //Throw(CAException(kAudioHardwareNotRunningError));
         }
     }
 }
@@ -1345,7 +1357,19 @@ void	BGM_Device::DoIOOperation(AudioObjectID inStreamObjectID, UInt32 inClientID
 		case kAudioServerPlugInIOOperationReadInput:
             {
                 CAMutex::Locker theIOLocker(mIOMutex);
-                ReadInputData(inIOBufferFrameSize, inIOCycleInfo.mInputTime.mSampleTime, ioMainBuffer);
+
+                // Copy the audio data out of our ring buffer.
+                //
+                // Take the IO mutex because, in testing, not taking it seemed to make this function
+                // occasionally miss its deadline and cause an audio glitch. It's hard to be sure
+                // that was actually the cause, but it's probably not worth the risk anyway.
+                //
+                // If an IO operation misses its deadline, the host will log this message:
+                //     Audio IO Overload inputs: '<private>' outputs: '<private>' cause: 'Unknown'
+                //     prewarming: no recovering: no
+                ReadInputData(inIOBufferFrameSize,
+                              inIOCycleInfo.mInputTime.mSampleTime,
+                              ioMainBuffer);
             }
 			break;
             
@@ -1384,21 +1408,23 @@ void	BGM_Device::DoIOOperation(AudioObjectID inStreamObjectID, UInt32 inClientID
             {
                 CAMutex::Locker theIOLocker(mIOMutex);
 
-				bool didChangeState =
-						mAudibleState.UpdateWithMixedIO(inIOBufferFrameSize,
-														inIOCycleInfo.mOutputTime.mSampleTime,
-														reinterpret_cast<const Float32*>(ioMainBuffer));
+                bool didChangeState =
+                        mAudibleState.UpdateWithMixedIO(
+                                inIOBufferFrameSize,
+                                inIOCycleInfo.mOutputTime.mSampleTime,
+                                reinterpret_cast<const Float32*>(ioMainBuffer));
 
                 if(didChangeState)
                 {
-                    // Send notifications. I'm pretty sure we don't have to use
-					// RequestDeviceConfigurationChange for this property, but the docs seemed a bit
-					// unclear to me.
+                    // Send notifications.
                     mTaskQueue.QueueAsync_SendPropertyNotification(
 							kAudioDeviceCustomPropertyDeviceAudibleState, GetObjectID());
                 }
 
-                WriteOutputData(inIOBufferFrameSize, inIOCycleInfo.mOutputTime.mSampleTime, ioMainBuffer);
+                // Copy the audio data into our ring buffer.
+                WriteOutputData(inIOBufferFrameSize,
+                                inIOCycleInfo.mOutputTime.mSampleTime,
+                                ioMainBuffer);
             }
 			break;
 
@@ -1425,54 +1451,69 @@ void	BGM_Device::EndIOOperation(UInt32 inOperationID, UInt32 inIOBufferFrameSize
 
 void	BGM_Device::ReadInputData(UInt32 inIOBufferFrameSize, Float64 inSampleTime, void* outBuffer)
 {
-	//	figure out where we are starting
-	UInt64 theSampleTime = static_cast<UInt64>(inSampleTime);
-	UInt32 theStartFrameOffset = theSampleTime % kLoopbackRingBufferFrameSize;
-	
-	//	figure out how many frames we need to copy
-	UInt32 theNumberFramesToCopy1 = inIOBufferFrameSize;
-	UInt32 theNumberFramesToCopy2 = 0;
-	if((theStartFrameOffset + theNumberFramesToCopy1) > kLoopbackRingBufferFrameSize)
-	{
-		theNumberFramesToCopy1 = kLoopbackRingBufferFrameSize - theStartFrameOffset;
-		theNumberFramesToCopy2 = inIOBufferFrameSize - theNumberFramesToCopy1;
-	}
-	
-	//	do the copying (the byte sizes here assume a 32 bit stereo sample format)
-	Float32* theDestination = reinterpret_cast<Float32*>(outBuffer);
-	memcpy(theDestination, mLoopbackRingBuffer + (theStartFrameOffset * 2), theNumberFramesToCopy1 * 8);
-	if(theNumberFramesToCopy2 > 0)
-	{
-		memcpy(theDestination + (theNumberFramesToCopy1 * 2), mLoopbackRingBuffer, theNumberFramesToCopy2 * 8);
+    // Wrap the provided buffer in an AudioBufferList.
+    AudioBufferList abl = {
+        .mNumberBuffers = 1,
+        .mBuffers[0] = {
+            .mNumberChannels = 2,
+            // Each frame is 2 Float32 samples (one per channel). The number of frames * the number
+            // of bytes per frame = the size of outBuffer in bytes.
+            .mDataByteSize = static_cast<UInt32>(inIOBufferFrameSize * sizeof(Float32) * 2),
+            .mData = outBuffer
+        }
+    };
+
+    // Copy the audio data from our ring buffer into the provided buffer.
+    CARingBufferError err =
+            mLoopbackRingBuffer.Fetch(&abl,
+                                      inIOBufferFrameSize,
+                                      static_cast<CARingBuffer::SampleTime>(inSampleTime));
+
+    // Handle errors.
+    switch (err)
+    {
+        case kCARingBufferError_CPUOverload:
+            // Write silence to the buffer.
+            memset(outBuffer, 0, abl.mBuffers[0].mDataByteSize);
+            break;
+        case kCARingBufferError_TooMuch:
+            // Should be impossible, but handle it just in case. Write silence to the buffer and
+            // return an error code.
+            memset(outBuffer, 0, abl.mBuffers[0].mDataByteSize);
+            Throw(CAException(kAudioHardwareIllegalOperationError));
+        case kCARingBufferError_OK:
+            break;
+        default:
+            throw CAException(kAudioHardwareUnspecifiedError);
     }
-    
-    //DebugMsg("BGM_Device::ReadInputData: Reading. theSampleTime=%llu theStartFrameOffset=%u theNumberFramesToCopy1=%u theNumberFramesToCopy2=%u", theSampleTime, theStartFrameOffset, theNumberFramesToCopy1, theNumberFramesToCopy2);
 }
 
 void	BGM_Device::WriteOutputData(UInt32 inIOBufferFrameSize, Float64 inSampleTime, const void* inBuffer)
 {
-	//	figure out where we are starting
-	UInt64 theSampleTime = static_cast<UInt64>(inSampleTime);
-	UInt32 theStartFrameOffset = theSampleTime % kLoopbackRingBufferFrameSize;
-	
-	//	figure out how many frames we need to copy
-	UInt32 theNumberFramesToCopy1 = inIOBufferFrameSize;
-	UInt32 theNumberFramesToCopy2 = 0;
-	if((theStartFrameOffset + theNumberFramesToCopy1) > kLoopbackRingBufferFrameSize)
-	{
-		theNumberFramesToCopy1 = kLoopbackRingBufferFrameSize - theStartFrameOffset;
-		theNumberFramesToCopy2 = inIOBufferFrameSize - theNumberFramesToCopy1;
-	}
-	
-	//	do the copying (the byte sizes here assume a 32 bit stereo sample format)
-	const Float32* theSource = reinterpret_cast<const Float32*>(inBuffer);
-	memcpy(mLoopbackRingBuffer + (theStartFrameOffset * 2), theSource, theNumberFramesToCopy1 * 8);
-	if(theNumberFramesToCopy2 > 0)
-	{
-		memcpy(mLoopbackRingBuffer, theSource + (theNumberFramesToCopy1 * 2), theNumberFramesToCopy2 * 8);
+    // Wrap the provided buffer in an AudioBufferList.
+    AudioBufferList abl = {
+        .mNumberBuffers = 1,
+        .mBuffers[0] = {
+            .mNumberChannels = 2,
+            // Each frame is 2 Float32 samples (one per channel). The number of frames * the number
+            // of bytes per frame = the size of inBuffer in bytes.
+            .mDataByteSize = static_cast<UInt32>(inIOBufferFrameSize * sizeof(Float32) * 2),
+            .mData = const_cast<void *>(inBuffer)
+        }
+    };
+
+    // Copy the audio data from the provided buffer into our ring buffer.
+    CARingBufferError err =
+            mLoopbackRingBuffer.Store(&abl,
+                                      inIOBufferFrameSize,
+                                      static_cast<CARingBuffer::SampleTime>(inSampleTime));
+
+    // Return an error code if we failed to store the data. (But ignore CPU overload, which would be
+    // temporary.)
+    if (err != kCARingBufferError_OK && err != kCARingBufferError_CPUOverload)
+    {
+        Throw(CAException(err));
     }
-    
-    //DebugMsg("BGM_Device::WriteOutputData: Writing. theSampleTime=%llu theStartFrameOffset=%u theNumberFramesToCopy1=%u theNumberFramesToCopy2=%u", theSampleTime, theStartFrameOffset, theNumberFramesToCopy1, theNumberFramesToCopy2);
 }
 
 void	BGM_Device::ApplyClientRelativeVolume(UInt32 inClientID, UInt32 inIOBufferFrameSize, void* ioBuffer) const

BGMDriver/BGMDriver/BGM_Device.h

@@ -17,8 +17,9 @@
 //  BGM_Device.h
 //  BGMDriver
 //
-//  Copyright © 2016, 2017 Kyle Neideck
-//  Portions copyright (C) 2013 Apple Inc. All Rights Reserved.
+//  Copyright © 2016, 2017, 2019 Kyle Neideck
+//  Copyright © 2019 Gordon Childs
+//  Copyright (C) 2013 Apple Inc. All Rights Reserved.
 //
 //  Based largely on SA_Device.h from Apple's SimpleAudioDriver Plug-In sample code.
 //  https://developer.apple.com/library/mac/samplecode/AudioDriverExamples
@@ -43,6 +44,7 @@
 // PublicUtility Includes
 #include "CAMutex.h"
 #include "CAVolumeCurve.h"
+#include "CARingBuffer.h"
 
 // System Includes
 #include <CoreFoundation/CoreFoundation.h>
@@ -237,7 +239,8 @@ private:
     
     #define kLoopbackRingBufferFrameSize    16384
     Float64                     mLoopbackSampleRate;
-	Float32						mLoopbackRingBuffer[kLoopbackRingBufferFrameSize * 2];
+    CARingBuffer                mLoopbackRingBuffer;
+
     // TODO: a comment explaining why we need a clock for loopback-only mode
     struct {
         Float64					hostTicksPerFrame = 0.0;

BGMDriver/BGMDriver/BGM_Object.cpp

@@ -18,7 +18,7 @@
 //  BGMDriver
 //
 //  Copyright © 2016 Kyle Neideck
-//  Portions copyright (C) 2013 Apple Inc. All Rights Reserved.
+//  Copyright (C) 2013 Apple Inc. All Rights Reserved.
 //
 //  Based largely on SA_Object.cpp from Apple's SimpleAudioDriver Plug-In sample code.
 //  https://developer.apple.com/library/mac/samplecode/AudioDriverExamples

BGMDriver/BGMDriver/BGM_Object.h

@@ -18,7 +18,7 @@
 //  BGMDriver
 //
 //  Copyright © 2016 Kyle Neideck
-//  Portions copyright (C) 2013 Apple Inc. All Rights Reserved.
+//  Copyright (C) 2013 Apple Inc. All Rights Reserved.
 //
 //  Based largely on SA_Object.h from Apple's SimpleAudioDriver Plug-In sample code.
 //  https://developer.apple.com/library/mac/samplecode/AudioDriverExamples
@@ -46,7 +46,7 @@
 //
 //	This is the base class for objects managed by BGM_ObjectMap. It's only job is to ensure that
 //	objects of this type have the proper external semantics for a reference counted object. This
-//	means that the desctructor is protected so that these objects cannot be deleted directly. Also,
+//	means that the destructor is protected so that these objects cannot be deleted directly. Also,
 //	these objects many not make a copy of another object or be assigned from another object. Note
 //	that the reference count of the object is tracked and owned by the BGM_ObjectMap.
 //
@@ -68,8 +68,8 @@
 //	not need to worry about being thread safe while Activate() is in progress.
 //
 //	Subclasses of this class must also implement Deactivate(). This method is called when the object
-//	is at the end of it's lifecycle. Once Deactivate() has been called, the object may no longer
-//	perform active opertions, including Deactivating other objects. This is based on the notion that
+//	is at the end of its lifecycle. Once Deactivate() has been called, the object may no longer
+//	perform active operations, including Deactivating other objects. This is based on the notion that
 //	all the objects have a definite point at which they are considered dead to the outside world.
 //	For example, an AudioDevice object is dead if it's hardware is unplugged. The point of death is
 //	the notification the owner of the device gets to signal that it has been unplugged. Note that it

BGMDriver/BGMDriver/BGM_PlugIn.cpp

@@ -18,7 +18,7 @@
 //  BGMDriver
 //
 //  Copyright © 2016, 2017 Kyle Neideck
-//  Portions copyright (C) 2013 Apple Inc. All Rights Reserved.
+//  Copyright (C) 2013 Apple Inc. All Rights Reserved.
 //
 //  Based largely on SA_PlugIn.cpp from Apple's SimpleAudioDriver Plug-In sample code.
 //  https://developer.apple.com/library/mac/samplecode/AudioDriverExamples

BGMDriver/BGMDriver/BGM_PlugIn.h

@@ -18,7 +18,7 @@
 //  BGMDriver
 //
 //  Copyright © 2016 Kyle Neideck
-//  Portions copyright (C) 2013 Apple Inc. All Rights Reserved.
+//  Copyright (C) 2013 Apple Inc. All Rights Reserved.
 //
 //  Based largely on SA_PlugIn.h from Apple's SimpleAudioDriver Plug-In sample code.
 //  https://developer.apple.com/library/mac/samplecode/AudioDriverExamples

BGMDriver/BGMDriver/BGM_PlugInInterface.cpp

@@ -18,7 +18,7 @@
 //  BGMDriver
 //
 //  Copyright © 2016, 2017 Kyle Neideck
-//  Portions copyright (C) 2013 Apple Inc. All Rights Reserved.
+//  Copyright (C) 2013 Apple Inc. All Rights Reserved.
 //
 //  Based largely on SA_PlugIn.cpp from Apple's SimpleAudioDriver Plug-In sample code.
 //  https://developer.apple.com/library/mac/samplecode/AudioDriverExamples
@@ -153,11 +153,11 @@ void*	BGM_Create(CFAllocatorRef inAllocator, CFUUIDRef inRequestedTypeUUID)
 {
 	//	This is the CFPlugIn factory function. Its job is to create the implementation for the given
 	//	type provided that the type is supported. Because this driver is simple and all its
-	//	initialization is handled via static initalization when the bundle is loaded, all that
+	//	initialization is handled via static initialization when the bundle is loaded, all that
 	//	needs to be done is to return the AudioServerPlugInDriverRef that points to the driver's
 	//	interface. A more complicated driver would create any base line objects it needs to satisfy
 	//	the IUnknown methods that are used to discover that actual interface to talk to the driver.
-	//	The majority of the driver's initilization should be handled in the Initialize() method of
+	//	The majority of the driver's initialization should be handled in the Initialize() method of
 	//	the driver's AudioServerPlugInDriverInterface.
 	
 	#pragma unused(inAllocator)
@@ -196,7 +196,7 @@ static HRESULT	BGM_QueryInterface(void* inDriver, REFIID inUUID, LPVOID* outInte
     	ThrowIf(theRequestedUUID == NULL, CAException(kAudioHardwareIllegalOperationError), "BGM_QueryInterface: failed to create the CFUUIDRef");
 
 		//	AudioServerPlugIns only support two interfaces, IUnknown (which has to be supported by all
-		//	CFPlugIns and AudioServerPlugInDriverInterface (which is the actual interface the HAL will
+		//	CFPlugIns) and AudioServerPlugInDriverInterface (which is the actual interface the HAL will
 		//	use).
 		ThrowIf(!CFEqual(theRequestedUUID, IUnknownUUID) && !CFEqual(theRequestedUUID, kAudioServerPlugInDriverInterfaceUUID), CAException(E_NOINTERFACE), "BGM_QueryInterface: requested interface is unsupported");
 		ThrowIf(gAudioServerPlugInDriverRefCount == UINT32_MAX, CAException(E_NOINTERFACE), "BGM_QueryInterface: the ref count is maxxed out");
@@ -268,7 +268,7 @@ static OSStatus	BGM_Initialize(AudioServerPlugInDriverRef inDriver, AudioServerP
 	//	The job of this method is, as the name implies, to get the driver initialized. One specific
 	//	thing that needs to be done is to store the AudioServerPlugInHostRef so that it can be used
 	//	later. Note that when this call returns, the HAL will scan the various lists the driver
-	//	maintains (such as the device list) to get the inital set of objects the driver is
+	//	maintains (such as the device list) to get the initial set of objects the driver is
 	//	publishing. So, there is no need to notifiy the HAL about any objects created as part of the
 	//	execution of this method.
 
@@ -397,7 +397,7 @@ static OSStatus	BGM_RemoveDeviceClient(AudioServerPlugInDriverRef inDriver, Audi
 
 static OSStatus	BGM_PerformDeviceConfigurationChange(AudioServerPlugInDriverRef inDriver, AudioObjectID inDeviceObjectID, UInt64 inChangeAction, void* inChangeInfo)
 {
-	//	This method is called to tell the device that it can perform the configuation change that it
+	//	This method is called to tell the device that it can perform the configuration change that it
 	//	had requested via a call to the host method, RequestDeviceConfigurationChange(). The
 	//	arguments, inChangeAction and inChangeInfo are the same as what was passed to
 	//	RequestDeviceConfigurationChange().

BGMDriver/BGMDriver/BGM_Stream.cpp

@@ -17,7 +17,7 @@
 //  BGMDriver
 //
 //  Copyright © 2017 Kyle Neideck
-//  Portions copyright (C) 2013 Apple Inc. All Rights Reserved.
+//  Copyright (C) 2013 Apple Inc. All Rights Reserved.
 //
 
 // Self Include
@@ -287,7 +287,7 @@ void    BGM_Stream::GetPropertyData(AudioObjectID inObjectID,
             break;
 
         case kAudioStreamPropertyLatency:
-            // This property returns any additonal presentation latency the stream has.
+            // This property returns any additional presentation latency the stream has.
             ThrowIf(inDataSize < sizeof(UInt32),
                     CAException(kAudioHardwareBadPropertySizeError),
                     "BGM_Stream::GetPropertyData: not enough space for the return "

BGMDriver/BGMDriver/BGM_VolumeControl.cpp

@@ -18,7 +18,7 @@
 //  BGMDriver
 //
 //  Copyright © 2016, 2017 Kyle Neideck
-//  Portions copyright (C) 2013 Apple Inc. All Rights Reserved.
+//  Copyright (C) 2013 Apple Inc. All Rights Reserved.
 //
 
 // Self Include

BGMDriver/BGMDriver/BGM_XPCHelper.m

@@ -14,10 +14,11 @@
 // along with Background Music. If not, see <http://www.gnu.org/licenses/>.
 
 //
-//  BGM_XPCHelper.cpp
+//  BGM_XPCHelper.m
 //  BGMDriver
 //
-//  Copyright © 2016, 2017 Kyle Neideck
+//  Copyright © 2016, 2017, 2020, 2024 Kyle Neideck
+//  Copyright © 2020 Aleksey Yurkevich
 //
 
 // Self Include
@@ -37,7 +38,7 @@
 
 static const UInt64 REMOTE_CALL_DEFAULT_TIMEOUT_SECS = 30;
 
-static NSXPCConnection* CreateXPCHelperConnection()
+static NSXPCConnection* CreateXPCHelperConnection(void)
 {
     // Create a connection to BGMXPCHelper's Mach service. If it isn't already running, launchd will start BGMXPCHelper when we send
     // a message to this connection.

BGMDriver/BGMDriver/DeviceClients/BGM_ClientMap.cpp

@@ -17,7 +17,7 @@
 //  BGM_ClientMap.cpp
 //  BGMDriver
 //
-//  Copyright © 2016 Kyle Neideck
+//  Copyright © 2016, 2017, 2019 Kyle Neideck
 //  Copyright © 2017 Andrew Tonner
 //
 
@@ -59,11 +59,13 @@ void    BGM_ClientMap::AddClient(BGM_Client inClient)
     // The shadow maps (which were the main maps until we swapped them) are now missing the new client. Add it again to
     // keep the sets of maps identical.
     AddClientToShadowMaps(inClient);
-    
-    // Remove the client from the past clients map (if it was in there)
+
+    // Insert the client into the past clients map. We do this here rather than in RemoveClient
+    // because some apps add multiple clients with the same bundle ID and we want to give them all
+    // the same settings (volume, etc.).
     if(inClient.mBundleID.IsValid())
     {
-        mPastClientMap.erase(inClient.mBundleID);
+        mPastClientMap[inClient.mBundleID] = inClient;
     }
 }
 
@@ -102,12 +104,6 @@ BGM_Client    BGM_ClientMap::RemoveClient(UInt32 inClientID)
     
     BGM_Client theClient = theClientItr->second;
     
-    // Insert the client into the past clients map
-    if(theClient.mBundleID.IsValid())
-    {
-        mPastClientMap[theClient.mBundleID] = theClient;
-    }
-    
     // Remove the client from the shadow maps
     mClientMapShadow.erase(theClientItr);
     mClientMapByPIDShadow.erase(theClient.mProcessID);

BGMDriver/BGMDriver/DeviceClients/BGM_ClientMap.h

@@ -53,7 +53,7 @@ class BGM_ClientTasks;
 //  removed by the HAL we add it to a map of past clients to keep track of settings specific to that
 //  client. (Currently only the client's volume.)
 //
-//  Since the maps are read from during IO, this class has to to be real-time safe when accessing
+//  Since the maps are read from during IO, this class has to be real-time safe when accessing
 //  them. So each map has an identical "shadow" map, which we use to buffer updates.
 //
 //  To update the clients we lock the shadow maps, modify them, have BGM_TaskQueue's real-time
@@ -182,8 +182,8 @@ private:
     std::map<CACFString, BGM_ClientPtrList>             mClientMapByBundleID;
     std::map<CACFString, BGM_ClientPtrList>             mClientMapByBundleIDShadow;
     
-    // Clients are added to mPastClientMap after they're removed so we can restore settings specific to them
-    // if they get added again.
+    // Clients are added to mPastClientMap so we can restore settings specific to them if they get
+    // added again.
     std::map<CACFString, BGM_Client>                    mPastClientMap;
     
 };