fix PCM memory leak

This reverts commit f3b62cc756.

Source/Engine/AudioStreamEngine.swift

@@ -137,7 +137,7 @@ class AudioStreamEngine: AudioEngine {
         Log.info(url)
         super.init(url: url, delegate: delegate, engineAudioFormat: AudioEngine.defaultEngineAudioFormat)
         do {
-            converter = try AudioConverter(withRemoteUrl: url, toEngineAudioFormat: AudioEngine.defaultEngineAudioFormat)
+            converter = try AudioConverter(withRemoteUrl: url, toEngineAudioFormat: AudioEngine.defaultEngineAudioFormat, withPCMBufferSize: PCM_BUFFER_SIZE)
         } catch {
             delegate?.didError()
         }
@@ -149,7 +149,7 @@ class AudioStreamEngine: AudioEngine {
             guard let self = self else { return }
             guard self.playingStatus != .ended else { return }
             
-            self.pollForNextBuffer()
+            self.pollForNextBufferRecursive()
             self.updateNetworkBufferRange()
             self.updateNeedle()
             self.updateIsPlaying()
@@ -162,11 +162,11 @@ class AudioStreamEngine: AudioEngine {
     //Called when
     //1. First time audio is finally parsed
     //2. When we run to the end of the network buffer and we're waiting again
-    private func pollForNextBuffer() {
+    private func pollForNextBufferRecursive() {
         guard shouldPollForNextBuffer else { return }
         
         do {
-            var nextScheduledBuffer: AVAudioPCMBuffer! = try converter.pullBuffer(withSize: PCM_BUFFER_SIZE)
+            var nextScheduledBuffer: AVAudioPCMBuffer! = try converter.pullBuffer()
             numberOfBuffersScheduledFromPoll += 1
             numberOfBuffersScheduledInTotal += 1
             
@@ -177,13 +177,13 @@ class AudioStreamEngine: AudioEngine {
                     self?.playerNode.scheduleBuffer(nextScheduledBuffer, completionCallbackType: .dataRendered, completionHandler: { (_) in
                         nextScheduledBuffer = nil
                         self?.numberOfBuffersScheduledInTotal -= 1
-                        self?.pollForNextBufferRecursionHelper()
+                        self?.pollForNextBufferRecursive()
                     })
                 } else {
                     self?.playerNode.scheduleBuffer(nextScheduledBuffer) {
                         nextScheduledBuffer = nil
                         self?.numberOfBuffersScheduledInTotal -= 1
-                        self?.pollForNextBufferRecursionHelper()
+                        self?.pollForNextBufferRecursive()
                     }
                 }
             }
@@ -200,32 +200,6 @@ class AudioStreamEngine: AudioEngine {
         }
     }
     
-    private func pollForNextBufferRecursionHelper() {
-        do {
-            let nextScheduledBuffer = try converter.pullBuffer(withSize: PCM_BUFFER_SIZE)
-            Log.debug("processed buffer for engine of frame lengthL \(nextScheduledBuffer.frameLength)")
-            numberOfBuffersScheduledInTotal += 1
-            
-            queue.async { [weak self] in
-                self?.playerNode.scheduleBuffer(nextScheduledBuffer) {
-                    self?.numberOfBuffersScheduledInTotal -= 1
-                    self?.pollForNextBufferRecursionHelper()
-                }
-                
-            }
-            
-        } catch ConverterError.reachedEndOfFile {
-            Log.info(ConverterError.reachedEndOfFile.localizedDescription)
-        } catch ConverterError.notEnoughData {
-            shouldPollForNextBuffer = true
-            Log.debug(ConverterError.notEnoughData.localizedDescription)
-        } catch ConverterError.superConcerningShouldNeverHappen {
-            Log.error(ConverterError.superConcerningShouldNeverHappen.localizedDescription)
-        } catch {
-            Log.debug(error.localizedDescription)
-        }
-    }
-    
     private func updateNetworkBufferRange() { //for ui
         let range = converter.pollNetworkAudioAvailabilityRange()
         isPlayable = (numberOfBuffersScheduledInTotal >= MIN_BUFFERS_TO_BE_PLAYABLE && range.1 > 0) && predictedStreamDuration > 0

Source/Engine/Converter/AudioConverter.swift

@@ -36,8 +36,8 @@ import AudioToolbox
 protocol AudioConvertable {
     var engineAudioFormat: AVAudioFormat {get}
     
-    init(withRemoteUrl url: AudioURL, toEngineAudioFormat: AVAudioFormat) throws
-    func pullBuffer(withSize size: AVAudioFrameCount) throws -> AVAudioPCMBuffer
+    init(withRemoteUrl url: AudioURL, toEngineAudioFormat: AVAudioFormat, withPCMBufferSize size: AVAudioFrameCount) throws
+    func pullBuffer() throws -> AVAudioPCMBuffer
     func pollPredictedDuration() -> Duration?
     func pollNetworkAudioAvailabilityRange() -> (Needle, Duration)
     func seek(_ needle: Needle)
@@ -70,13 +70,20 @@ class AudioConverter: AudioConvertable {
     
     //From protocol
     public var engineAudioFormat: AVAudioFormat
+    let pcmBufferSize: AVAudioFrameCount
     
     //Field
     var converter: AudioConverterRef? //set by AudioConverterNew
     var currentAudioPacketIndex: AVAudioPacketCount = 0
     
-    required init(withRemoteUrl url: AudioURL, toEngineAudioFormat: AVAudioFormat) throws {
+    // use to store reference to the allocated buffers from the converter to properly deallocate them before the next packet is being converted
+    var converterBuffer: UnsafeMutableRawPointer?
+    var converterDescriptions: UnsafeMutablePointer<AudioStreamPacketDescription>?
+    
+    required init(withRemoteUrl url: AudioURL, toEngineAudioFormat: AVAudioFormat, withPCMBufferSize size: AVAudioFrameCount) throws {
         self.engineAudioFormat = toEngineAudioFormat
+        self.pcmBufferSize = size
+        
         do {
             parser = try AudioParser(withRemoteUrl: url, parsedFileAudioFormatCallback: {
                 [weak self] (fileAudioFormat: AVAudioFormat) in
@@ -108,17 +115,17 @@ class AudioConverter: AudioConvertable {
         }
     }
     
-    func pullBuffer(withSize size: AVAudioFrameCount) throws -> AVAudioPCMBuffer {
+    func pullBuffer() throws -> AVAudioPCMBuffer {
         guard let converter = converter else {
             Log.debug("reader_error trying to read before converter has been created")
             throw ConverterError.cannotCreatePCMBufferWithoutConverter
         }
         
-        guard let pcmBuffer = AVAudioPCMBuffer(pcmFormat: engineAudioFormat, frameCapacity: size) else {
+        guard let pcmBuffer = AVAudioPCMBuffer(pcmFormat: engineAudioFormat, frameCapacity: pcmBufferSize) else {
             Log.monitor(ConverterError.failedToCreatePCMBuffer.errorDescription as Any)
             throw ConverterError.failedToCreatePCMBuffer
         }
-        pcmBuffer.frameLength = size
+        pcmBuffer.frameLength = pcmBufferSize
         
         /**
          The whole thing is wrapped in queue.sync() because the converter listener
@@ -127,7 +134,7 @@ class AudioConverter: AudioConvertable {
          */
         return try queue.sync { () -> AVAudioPCMBuffer in
             let framesPerPacket = engineAudioFormat.streamDescription.pointee.mFramesPerPacket
-            var numberOfPacketsWeWantTheBufferToFill = size / framesPerPacket
+            var numberOfPacketsWeWantTheBufferToFill = pcmBuffer.frameLength / framesPerPacket
             
             let context = unsafeBitCast(self, to: UnsafeMutableRawPointer.self)
             let status = AudioConverterFillComplexBuffer(converter, ConverterListener, context, &numberOfPacketsWeWantTheBufferToFill, pcmBuffer.mutableAudioBufferList, nil)

Source/Engine/Converter/AudioConverterListener.swift

@@ -65,6 +65,10 @@ func ConverterListener(_ converter: AudioConverterRef, _ packetCount: UnsafeMuta
         return ReaderShouldNotHappenError
     }
     
+    if let lastBuffer = selfAudioConverter.converterBuffer {
+        lastBuffer.deallocate()
+    }
+    
     // Copy data over (note we've only processing a single packet of data at a time)
     var packet = audioPacket.1
     let packetByteCount = packet.count //this is not the count of an array
@@ -75,6 +79,12 @@ func ConverterListener(_ converter: AudioConverterRef, _ packetCount: UnsafeMuta
     })
     ioData.pointee.mBuffers.mDataByteSize = UInt32(packetByteCount)
     
+    selfAudioConverter.converterBuffer = ioData.pointee.mBuffers.mData
+    
+    if let lastDescription = selfAudioConverter.converterDescriptions {
+        lastDescription.deallocate()
+    }
+    
     // Handle packet descriptions for compressed formats (MP3, AAC, etc)
     let fileFormatDescription = fileAudioFormat.streamDescription.pointee
     if fileFormatDescription.mFormatID != kAudioFormatLinearPCM {
@@ -86,6 +96,8 @@ func ConverterListener(_ converter: AudioConverterRef, _ packetCount: UnsafeMuta
         outPacketDescriptions?.pointee?.pointee.mVariableFramesInPacket = 0
     }
     
+    selfAudioConverter.converterDescriptions = outPacketDescriptions?.pointee
+    
     packetCount.pointee = 1
     
     //we've successfully given a packet to the LPCM buffer now we can process the next audio packet