Fix update directories not being pruned (bad merge)

Conflicts:
	External/ReactiveCocoa
	Squirrel/SQRLShipItLauncher.m
	Squirrel/SQRLUpdater.m

Squirrel.xcodeproj/xcshareddata/xcschemes/shipit.xcscheme

@@ -20,6 +20,20 @@
                ReferencedContainer = "container:Squirrel.xcodeproj">
             </BuildableReference>
          </BuildActionEntry>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "NO"
+            buildForArchiving = "NO"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "D0C22BEE179CC00E00158214"
+               BuildableName = "SquirrelTests.octest"
+               BlueprintName = "SquirrelTests"
+               ReferencedContainer = "container:Squirrel.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
       </BuildActionEntries>
    </BuildAction>
    <TestAction

Squirrel/RACSignal+SQRLTransactionExtensions.m

@@ -97,15 +97,12 @@ static RACDisposable *SQRLCreateTransaction(NSString *name, NSString *descriptio
 		va_end(args);
 	}
 
-	return [[RACSignal createSignal:^(id<RACSubscriber> subscriber) {
-		RACDisposable *transactionDisposable = SQRLCreateTransaction(name, description);
-		RACDisposable *subscriptionDisposable = [self subscribe:subscriber];
-
-		return [RACDisposable disposableWithBlock:^{
-			[subscriptionDisposable dispose];
-			[transactionDisposable dispose];
-		}];
-	}] setNameWithFormat:@"[%@] -sqrl_addTransactionWithName: %@ description: %@", self.name, name, description];
+	return [[RACSignal
+		create:^(id<RACSubscriber> subscriber) {
+			[subscriber.disposable addDisposable:SQRLCreateTransaction(name, description)];
+			[self subscribe:subscriber];
+		}]
+		setNameWithFormat:@"[%@] -sqrl_addTransactionWithName: %@ description: %@", self.name, name, description];
 }
 
 - (RACSignal *)sqrl_addSubscriptionTransactionWithName:(NSString *)name description:(NSString *)descriptionFormat, ... {
@@ -117,13 +114,13 @@ static RACDisposable *SQRLCreateTransaction(NSString *name, NSString *descriptio
 		va_end(args);
 	}
 
-	return [[RACSignal createSignal:^(id<RACSubscriber> subscriber) {
-		RACDisposable *transactionDisposable = SQRLCreateTransaction(name, description);
-		RACDisposable *subscriptionDisposable = [self subscribe:subscriber];
-		[transactionDisposable dispose];
-
-		return subscriptionDisposable;
-	}] setNameWithFormat:@"[%@] -sqrl_addSubscriptionTransactionWithName: %@ description: %@", self.name, name, description];
+	return [[RACSignal
+		create:^(id<RACSubscriber> subscriber) {
+			RACDisposable *transactionDisposable = SQRLCreateTransaction(name, description);
+			[self subscribe:subscriber];
+			[transactionDisposable dispose];
+		}]
+		setNameWithFormat:@"[%@] -sqrl_addSubscriptionTransactionWithName: %@ description: %@", self.name, name, description];
 }
 
 @end

Squirrel/SQRLCodeSignature.m

@@ -83,7 +83,7 @@ const NSInteger SQRLCodeSignatureErrorCouldNotCreateStaticCode = -2;
 - (RACSignal *)verifyBundleAtURL:(NSURL *)bundleURL {
 	NSParameterAssert(bundleURL != nil);
 
-	return [[RACSignal createSignal:^ RACDisposable * (id<RACSubscriber> subscriber) {
+	return [[RACSignal create:^(id<RACSubscriber> subscriber) {
 		SecStaticCodeRef staticCode = NULL;
 		
 		OSStatus result = SecStaticCodeCreateWithPath((__bridge CFURLRef)bundleURL, kSecCSDefaultFlags, &staticCode);
@@ -100,8 +100,10 @@ const NSInteger SQRLCodeSignatureErrorCouldNotCreateStaticCode = -2;
 			if (failureReason != nil) userInfo[NSLocalizedFailureReasonErrorKey] = failureReason;
 			
 			[subscriber sendError:[NSError errorWithDomain:SQRLCodeSignatureErrorDomain code:SQRLCodeSignatureErrorCouldNotCreateStaticCode userInfo:userInfo]];
-			return nil;
+			return;
 		}
+
+		if (subscriber.disposable.disposed) return;
 		
 		CFErrorRef validityError = NULL;
 		result = SecStaticCodeCheckValidityWithErrors(staticCode, kSecCSCheckAllArchitectures, (__bridge SecRequirementRef)self.requirement, &validityError);
@@ -119,11 +121,10 @@ const NSInteger SQRLCodeSignatureErrorCouldNotCreateStaticCode = -2;
 			if (validityError != NULL) userInfo[NSUnderlyingErrorKey] = (__bridge NSError *)validityError;
 			
 			[subscriber sendError:[NSError errorWithDomain:SQRLCodeSignatureErrorDomain code:SQRLCodeSignatureErrorDidNotPass userInfo:userInfo]];
-			return nil;
+			return;
 		}
 		
 		[subscriber sendCompleted];
-		return nil;
 	}] setNameWithFormat:@"-verifyCodeSignatureOfBundle: %@", bundleURL];
 }
 

Squirrel/SQRLInstaller.h

@@ -34,7 +34,9 @@ extern const NSInteger SQRLInstallerErrorInvalidState;
 // There was an error moving a bundle across volumes.
 extern const NSInteger SQRLInstallerErrorMovingAcrossVolumes;
 
-@class RACCommand;
+@class RACSignal;
+@class RACAction;
+@class SQRLShipItState;
 @class SQRLDirectoryManager;
 
 // Performs the installation of an update, using the `SQRLShipItState` on disk,
@@ -44,21 +46,20 @@ extern const NSInteger SQRLInstallerErrorMovingAcrossVolumes;
 // terminated.
 @interface SQRLInstaller : NSObject
 
-// When executed with a `SQRLShipItState`, attempts to install the update or
-// resume an in-progress installation.
+// Attempts to install the update or resume an in-progress installation.
 //
-// Each execution will complete or error on an unspecified scheduler when
+// Returns a signal which completes or errors on an unspecified scheduler when
 // installation has completed or failed.
-@property (nonatomic, strong, readonly) RACCommand *installUpdateCommand;
+- (RACSignal *)installUpdateWithState:(SQRLShipItState *)state;
 
-// When executed with a `SQRLShipItState`, aborts an installation, and attempts
-// to restore the old version of the application if necessary.
+// Aborts an installation, and attempts to restore the old version of the
+// application if necessary.
 //
-// This must not be executed while `installUpdateCommand` is executing.
+// This must not be executed while `installUpdateWithState:` is executing.
 //
-// Each execution will complete or error on an unspecified scheduler once
+// Returns a signal while completes or errors on an unspecified scheduler once
 // aborting/recovery has finished.
-@property (nonatomic, strong, readonly) RACCommand *abortInstallationCommand;
+- (RACSignal *)abortInstallationWithState:(SQRLShipItState *)state;
 
 // Initializes an installer using the given directory manager to read and write the
 // state of the installation.

Squirrel/SQRLInstaller.m

@@ -145,44 +145,34 @@ typedef struct {
 	if (self == nil) return nil;
 
 	_directoryManager = directoryManager;
-
-	@weakify(self);
-
-	RACSignal *aborting = [[[[RACObserve(self, abortInstallationCommand)
-		ignore:nil]
-		map:^(RACCommand *command) {
-			return command.executing;
-		}]
-		switchToLatest]
-		setNameWithFormat:@"aborting"];
-
-	_installUpdateCommand = [[RACCommand alloc] initWithEnabled:[aborting not] signalBlock:^(SQRLShipItState *state) {
-		@strongify(self);
-		NSParameterAssert(state != nil);
-
-		return [[self
-			resumeInstallationFromState:state]
-			sqrl_addTransactionWithName:NSLocalizedString(@"Updating", nil) description:NSLocalizedString(@"%@ is being updated, and interrupting the process could corrupt the application", nil), state.targetBundleURL.path];
-	}];
-
-	_abortInstallationCommand = [[RACCommand alloc] initWithEnabled:[self.installUpdateCommand.executing not] signalBlock:^(SQRLShipItState *state) {
-		@strongify(self);
-		NSParameterAssert(state != nil);
-
-		return [[[RACSignal
-			zip:@[
-				[self getRequiredKey:@keypath(state.targetBundleURL) fromState:state],
-				[self getRequiredKey:@keypath(state.codeSignature) fromState:state]
-			] reduce:^(NSURL *targetBundleURL, SQRLCodeSignature *codeSignature) {
-				return [self verifyBundleAtURL:targetBundleURL usingSignature:codeSignature recoveringUsingBackupAtURL:state.backupBundleURL];
-			}]
-			flatten]
-			sqrl_addTransactionWithName:NSLocalizedString(@"Aborting update", nil) description:NSLocalizedString(@"An update to %@ is being rolled back, and interrupting the process could corrupt the application", nil), state.targetBundleURL.path];
-	}];
 	
 	return self;
 }
 
+#pragma mark Actions
+
+- (RACSignal *)installUpdateWithState:(SQRLShipItState *)state {
+	NSParameterAssert(state != nil);
+
+	return [[self
+		resumeInstallationFromState:state]
+		sqrl_addTransactionWithName:NSLocalizedString(@"Updating", nil) description:NSLocalizedString(@"%@ is being updated, and interrupting the process could corrupt the application", nil), state.targetBundleURL.path];
+}
+
+- (RACSignal *)abortInstallationWithState:(SQRLShipItState *)state {
+	NSParameterAssert(state != nil);
+
+	return [[[RACSignal
+		zip:@[
+			[self getRequiredKey:@keypath(state.targetBundleURL) fromState:state],
+			[self getRequiredKey:@keypath(state.codeSignature) fromState:state]
+		] reduce:^(NSURL *targetBundleURL, SQRLCodeSignature *codeSignature) {
+			return [self verifyBundleAtURL:targetBundleURL usingSignature:codeSignature recoveringUsingBackupAtURL:state.backupBundleURL];
+		}]
+		flatten]
+		sqrl_addTransactionWithName:NSLocalizedString(@"Aborting update", nil) description:NSLocalizedString(@"An update to %@ is being rolled back, and interrupting the process could corrupt the application", nil), state.targetBundleURL.path];
+}
+
 #pragma mark Installer State
 
 - (RACSignal *)getRequiredKey:(NSString *)key fromState:(SQRLShipItState *)state {
@@ -262,13 +252,12 @@ typedef struct {
 			nextState = dispatchTable[tableIndex + 1].installerState;
 		}
 
-		return [[step
+		return [[[step
 			doCompleted:^{
 				NSLog(@"Completed state %i", (int)installerState);
 			}]
-			then:^{
-				return [RACSignal return:@(nextState)];
-			}];
+			ignoreValues]
+			concat:[RACSignal return:@(nextState)]];
 	}];
 
 	return [[self
@@ -365,11 +354,9 @@ typedef struct {
 					// failure. Try recovering it if it did.
 					return [[self
 						verifyBundleAtURL:targetBundleURL usingSignature:codeSignature recoveringUsingBackupAtURL:backupBundleURL]
-						then:^{
-							// Recovery succeeded, but we still want to pass
-							// through the original error.
-							return [RACSignal error:error];
-						}];
+						// Recovery succeeded, but we still want to pass
+						// through the original error.
+						concat:[RACSignal error:error]];
 				}];
 		}]
 		flatten]
@@ -387,11 +374,9 @@ typedef struct {
 		] reduce:^(NSURL *targetBundleURL, NSURL *backupBundleURL, SQRLCodeSignature *codeSignature) {
 			return [[self
 				verifyBundleAtURL:targetBundleURL usingSignature:codeSignature recoveringUsingBackupAtURL:backupBundleURL]
-				then:^{
-					return [[self
-						deleteBackupAtURL:backupBundleURL]
-						catchTo:[RACSignal empty]];
-				}];
+				concat:[[self
+					deleteBackupAtURL:backupBundleURL]
+					catchTo:[RACSignal empty]]];
 		}]
 		flatten]
 		setNameWithFormat:@"%@ -verifyInPlaceWithState: %@", self, state];
@@ -438,26 +423,23 @@ typedef struct {
 - (RACSignal *)deleteBackupAtURL:(NSURL *)backupURL {
 	NSParameterAssert(backupURL != nil);
 
-	return [[[RACSignal
+	return [[RACSignal
 		defer:^{
 			NSError *error = nil;
-			if ([NSFileManager.defaultManager removeItemAtURL:backupURL error:&error]) {
-				return [RACSignal empty];
-			} else {
+			if (![NSFileManager.defaultManager removeItemAtURL:backupURL error:&error]) {
 				return [RACSignal error:error];
 			}
-		}]
-		then:^{
+
 			// Also remove the temporary directory that the backup lived in.
 			NSURL *temporaryDirectoryURL = backupURL.URLByDeletingLastPathComponent;
 
 			// However, use rmdir() to skip it in case there are other files
 			// contained within (for whatever reason).
-			if (rmdir(temporaryDirectoryURL.path.fileSystemRepresentation) == 0) {
-				return [RACSignal empty];
-			} else {
+			if (rmdir(temporaryDirectoryURL.path.fileSystemRepresentation) != 0) {
 				return [RACSignal error:[NSError errorWithDomain:NSPOSIXErrorDomain code:errno userInfo:nil]];
 			}
+
+			return [RACSignal empty];
 		}]
 		setNameWithFormat:@"%@ -deleteBackupAtURL: %@", self, backupURL];
 }
@@ -471,10 +453,11 @@ typedef struct {
 		catch:^(NSError *error) {
 			if (backupBundleURL == nil) return [RACSignal error:error];
 
-			return [[[[self
-				installItemAtURL:bundleURL fromURL:backupBundleURL]
-				initially:^{
+			return [[[RACSignal
+				defer:^{
 					[NSFileManager.defaultManager removeItemAtURL:bundleURL error:NULL];
+
+					return [self installItemAtURL:bundleURL fromURL:backupBundleURL];
 				}]
 				doCompleted:^{
 					NSLog(@"Restored backup bundle to %@", bundleURL);
@@ -495,9 +478,7 @@ typedef struct {
 
 	return [[[[self
 		verifyBundleAtURL:targetURL usingSignature:signature recoveringUsingBackupAtURL:nil]
-		then:^{
-			return [RACSignal return:@YES];
-		}]
+		concat:[RACSignal return:@YES]]
 		catch:^(NSError *error) {
 			BOOL directory;
 			if ([NSFileManager.defaultManager fileExistsAtPath:sourceURL.path isDirectory:&directory]) {
@@ -563,7 +544,7 @@ typedef struct {
 				return YES;
 			}];
 
-			return enumerator.rac_sequence.signal;
+			return enumerator.allObjects.rac_signal;
 		}]
 		flattenMap:^(NSURL *URL) {
 			const char *path = URL.path.fileSystemRepresentation;

Squirrel/SQRLShipItLauncher.m

@@ -72,7 +72,7 @@ const NSInteger SQRLShipItLauncherErrorCouldNotStartService = 1;
 
 + (RACSignal *)shipItAuthorization {
 	return [[RACSignal
-		createSignal:^ RACDisposable * (id<RACSubscriber> subscriber) {
+		create:^(id<RACSubscriber> subscriber) {
 			AuthorizationItem rightItems[] = {
 				{
 					.name = kSMRightModifySystemDaemons,
@@ -116,8 +116,6 @@ const NSInteger SQRLShipItLauncherErrorCouldNotStartService = 1;
 			} else {
 				[subscriber sendError:[NSError errorWithDomain:NSOSStatusErrorDomain code:authorizationError userInfo:nil]];
 			}
-
-			return nil;
 		}]
 		setNameWithFormat:@"+shipItAuthorization"];
 }

Squirrel/SQRLTerminationListener.m

@@ -45,7 +45,7 @@
 	return [[[[RACSignal
 		defer:^{
 			NSArray *apps = [NSRunningApplication runningApplicationsWithBundleIdentifier:self.bundleIdentifier];
-			return [apps.rac_sequence signalWithScheduler:RACScheduler.immediateScheduler];
+			return apps.rac_signal;
 		}]
 		filter:^(NSRunningApplication *application) {
 			return [application.bundleURL.URLByStandardizingPath isEqual:self.bundleURL];
@@ -60,7 +60,7 @@
 
 - (RACSignal *)waitForTerminationOfProcessIdentifier:(pid_t)processIdentifier {
 	return [[RACSignal
-		createSignal:^(id<RACSubscriber> subscriber) {
+		create:^(id<RACSubscriber> subscriber) {
 			dispatch_source_t source = dispatch_source_create(DISPATCH_SOURCE_TYPE_PROC, processIdentifier, DISPATCH_PROC_EXIT, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0));
 
 			dispatch_source_set_registration_handler(source, ^{
@@ -72,10 +72,10 @@
 			});
 
 			dispatch_resume(source);
-			return [RACDisposable disposableWithBlock:^{
+			[subscriber.disposable addDisposable:[RACDisposable disposableWithBlock:^{
 				dispatch_source_cancel(source);
 				dispatch_release(source);
-			}];
+			}]];
 		}]
 		setNameWithFormat:@"%@ -waitForTerminationOfProcessIdentifier: %i", self, (int)processIdentifier];
 }

Squirrel/SQRLUpdater.h

@@ -43,7 +43,7 @@ extern NSString * const SQRLUpdaterServerDataErrorKey;
 // error with code `SQRLUpdaterErrorInvalidJSON` is generated.
 extern NSString * const SQRLUpdaterJSONObjectErrorKey;
 
-@class RACCommand;
+@class RACAction;
 @class RACDisposable;
 @class RACSignal;
 
@@ -52,14 +52,12 @@ extern NSString * const SQRLUpdaterJSONObjectErrorKey;
 
 // Kicks off a check for updates.
 //
-// If an update is available, it will be sent on `updates` once downloaded.
-@property (nonatomic, strong, readonly) RACCommand *checkForUpdatesCommand;
+// If an update is available, it will be sent on
+// `[checkForUpdatesAction deferred]` and `updates` once downloaded.
+@property (nonatomic, strong, readonly) RACAction *checkForUpdatesAction;
 
 // Sends an `SQRLDownloadedUpdate` object on the main thread whenever a new
-// update is available.
-//
-// This signal is actually just `checkForUpdatesCommand.executionSignals`,
-// flattened for convenience.
+// update is available. Completes when the receiver deallocates.
 @property (nonatomic, strong, readonly) RACSignal *updates;
 
 // The request that will be sent to check for updates.
@@ -106,8 +104,8 @@ extern NSString * const SQRLUpdaterJSONObjectErrorKey;
 // relaunch. Otherwise, you can simply use `-[NSApplication terminate:]` or any
 // other exit mechanism.
 //
-// After invoking this method, the receiver is responsible for terminating the
-// application upon success. The app must not be terminated in any other way
+// After subscribing to this signal, the receiver is responsible for terminating
+// the application upon success. The app must not be terminated in any other way
 // unless an error occurs.
 //
 // Returns a signal that will error on the main scheduler if anything goes

Squirrel/SQRLUpdater.m

@@ -136,14 +136,15 @@ static NSString * const SQRLUpdaterUniqueTemporaryDirectoryPrefix = @"update.";
 
 @end
 
-@implementation SQRLUpdater
+@implementation SQRLUpdater {
+	RACSubject *_updates;
+}
 
 #pragma mark Properties
 
 - (RACSignal *)updates {
-	return [[self.checkForUpdatesCommand.executionSignals
-		concat]
-		setNameWithFormat:@"%@ -updates", self];
+	return [_updates
+		deliverOn:RACScheduler.mainThreadScheduler];
 }
 
 #pragma mark Lifecycle
@@ -174,10 +175,9 @@ static NSString * const SQRLUpdaterUniqueTemporaryDirectoryPrefix = @"update.";
 #endif
 	}
 
-	BOOL updatesDisabled = (getenv("DISABLE_UPDATE_CHECK") != NULL);
 	@weakify(self);
 
-	_prunedUpdateDirectories = [[[[RACSignal
+	_prunedUpdateDirectories = [[[[[[[[RACSignal
 		defer:^{
 			SQRLDirectoryManager *directoryManager = [[SQRLDirectoryManager alloc] initWithApplicationIdentifier:SQRLShipItLauncher.shipItJobLabel];
 			return [directoryManager applicationSupportURL];
@@ -189,7 +189,7 @@ static NSString * const SQRLUpdaterUniqueTemporaryDirectoryPrefix = @"update.";
 				return YES;
 			}];
 
-			return [[enumerator.rac_sequence.signal
+			return [[enumerator.allObjects.rac_signal
 				filter:^(NSURL *enumeratedURL) {
 					NSString *name = enumeratedURL.lastPathComponent;
 					return [name hasPrefix:SQRLUpdaterUniqueTemporaryDirectoryPrefix];
@@ -201,57 +201,32 @@ static NSString * const SQRLUpdaterUniqueTemporaryDirectoryPrefix = @"update.";
 					}
 				}];
 		}]
-		replayLazily]
+		collect]
+		// These operators ensure that the actual work only executes once,
+		// without starting it immediately.
+		concat:[RACSignal never]]
+		shareWhileActive]
+		take:1]
+		flattenMap:^(NSArray *URLs) {
+			return URLs.rac_signal;
+		}]
 		setNameWithFormat:@"%@ -prunedUpdateDirectories", self];
 
-	_checkForUpdatesCommand = [[RACCommand alloc] initWithEnabled:[RACSignal return:@(!updatesDisabled)] signalBlock:^(id _) {
-		@strongify(self);
-		NSParameterAssert(self.updateRequest != nil);
+	_checkForUpdatesAction = [[[RACSignal
+		defer:^{
+			@strongify(self);
+			return [RACSignal return:self.updateRequest];
+		}]
+		flattenMap:^(NSURLRequest *request) {
+			return [self checkForUpdates:request];
+		}]
+		action];
 
-		// TODO: Maybe allow this to be an argument to the command?
-		NSMutableURLRequest *request = [self.updateRequest mutableCopy];
-		[request setValue:@"application/json" forHTTPHeaderField:@"Accept"];
+	_updates = [[RACSubject
+		subject]
+		setNameWithFormat:@"%@ updates", self];
 
-		// Prune old updates before the first update check.
-		return [[[[[[[self.prunedUpdateDirectories
-			catch:^(NSError *error) {
-				NSLog(@"Error pruning old updates: %@", error);
-				return [RACSignal empty];
-			}]
-			then:^{
-				return [NSURLConnection rac_sendAsynchronousRequest:request];
-			}]
-			reduceEach:^(NSURLResponse *response, NSData *bodyData) {
-				if ([response isKindOfClass:NSHTTPURLResponse.class]) {
-					NSHTTPURLResponse *httpResponse = (id)response;
-					if (!(httpResponse.statusCode >= 200 && httpResponse.statusCode <= 299)) {
-						NSDictionary *errorInfo = @{
-							NSLocalizedDescriptionKey: NSLocalizedString(@"Update check failed", nil),
-							NSLocalizedRecoverySuggestionErrorKey: NSLocalizedString(@"The server sent an invalid response. Try again later.", nil),
-							SQRLUpdaterServerDataErrorKey: bodyData,
-						};
-						NSError *error = [NSError errorWithDomain:SQRLUpdaterErrorDomain code:SQRLUpdaterErrorInvalidServerResponse userInfo:errorInfo];
-						return [RACSignal error:error];
-					}
-
-					if (httpResponse.statusCode == 204 /* No Content */) {
-						return [RACSignal empty];
-					}
-				}
-
-				return [RACSignal return:bodyData];
-			}]
-			flatten]
-			flattenMap:^(NSData *data) {
-				return [self updateFromJSONData:data];
-			}]
-			flattenMap:^(SQRLUpdate *update) {
-				return [self downloadAndPrepareUpdate:update];
-			}]
-			deliverOn:RACScheduler.mainThreadScheduler];
-	}];
-
-	_shipItLauncher = [[[RACSignal
+	_shipItLauncher = [[[[[[[RACSignal
 		defer:^{
 			NSURL *targetURL = NSRunningApplication.currentApplication.bundleURL;
 
@@ -263,31 +238,90 @@ static NSString * const SQRLUpdaterUniqueTemporaryDirectoryPrefix = @"update.";
 			// wait for another, more canonical error.
 			return [SQRLShipItLauncher launchPrivileged:(gotWritable && !targetWritable.boolValue)];
 		}]
-		replayLazily]
+		// These operators ensure that the actual work only executes once,
+		// without starting it immediately. Super hacky.
+		concat:[RACSignal return:RACUnit.defaultUnit]]
+		concat:[RACSignal never]]
+		shareWhileActive]
+		take:1]
+		ignoreValues]
 		setNameWithFormat:@"shipItLauncher"];
 	
 	return self;
 }
 
+- (void)dealloc {
+	[_updates sendCompleted];
+}
+
 #pragma mark Checking for Updates
 
 - (RACDisposable *)startAutomaticChecksWithInterval:(NSTimeInterval)interval {
 	@weakify(self);
 
-	return [[[[[RACSignal
+	return [[[[RACSignal
 		interval:interval onScheduler:[RACScheduler schedulerWithPriority:RACSchedulerPriorityBackground]]
 		flattenMap:^(id _) {
 			@strongify(self);
-			return [[self.checkForUpdatesCommand
-				execute:RACUnit.defaultUnit]
+
+			return [[[self.checkForUpdatesAction
+				signalWithValue:nil]
+				ignoreValues]
 				catch:^(NSError *error) {
 					NSLog(@"Error checking for updates: %@", error);
 					return [RACSignal empty];
 				}];
 		}]
 		takeUntil:self.rac_willDeallocSignal]
-		publish]
-		connect];
+		subscribeCompleted:^{}];
+}
+
+- (RACSignal *)checkForUpdates:(NSURLRequest *)request {
+	NSParameterAssert(request != nil);
+
+	BOOL updatesDisabled = (getenv("DISABLE_UPDATE_CHECK") != NULL);
+	if (updatesDisabled) return [RACSignal empty];
+
+	NSMutableURLRequest *newRequest = [request mutableCopy];
+	[newRequest setValue:@"application/json" forHTTPHeaderField:@"Accept"];
+
+	return [[[[[[[[self.prunedUpdateDirectories
+		catch:^(NSError *error) {
+			NSLog(@"Error pruning old updates: %@", error);
+			return [RACSignal empty];
+		}]
+		ignoreValues]
+		concat:[NSURLConnection rac_sendAsynchronousRequest:newRequest]]
+		reduceEach:^(NSURLResponse *response, NSData *bodyData) {
+			if ([response isKindOfClass:NSHTTPURLResponse.class]) {
+				NSHTTPURLResponse *httpResponse = (id)response;
+				if (!(httpResponse.statusCode >= 200 && httpResponse.statusCode <= 299)) {
+					NSDictionary *errorInfo = @{
+						NSLocalizedDescriptionKey: NSLocalizedString(@"Update check failed", nil),
+						NSLocalizedRecoverySuggestionErrorKey: NSLocalizedString(@"The server sent an invalid response. Try again later.", nil),
+						SQRLUpdaterServerDataErrorKey: bodyData,
+					};
+					NSError *error = [NSError errorWithDomain:SQRLUpdaterErrorDomain code:SQRLUpdaterErrorInvalidServerResponse userInfo:errorInfo];
+					return [RACSignal error:error];
+				}
+
+				if (httpResponse.statusCode == 204 /* No Content */) {
+					return [RACSignal empty];
+				}
+			}
+
+			return [RACSignal return:bodyData];
+		}]
+		flatten]
+		flattenMap:^(NSData *data) {
+			return [self updateFromJSONData:data];
+		}]
+		flattenMap:^(SQRLUpdate *update) {
+			return [self downloadAndPrepareUpdate:update];
+		}]
+		doNext:^(SQRLDownloadedUpdate *update) {
+			[self->_updates sendNext:update];
+		}];
 }
 
 - (RACSignal *)updateFromJSONData:(NSData *)data {
@@ -403,9 +437,7 @@ static NSString * const SQRLUpdaterUniqueTemporaryDirectoryPrefix = @"update.";
 					}
 				}];
 		}]
-		then:^{
-			return [self updateBundleMatchingCurrentApplicationInDirectory:downloadDirectory];
-		}]
+		concat:[self updateBundleMatchingCurrentApplicationInDirectory:downloadDirectory]]
 		setNameWithFormat:@"%@ -downloadBundleForUpdate: %@ intoDirectory: %@", self, update, downloadDirectory];
 }
 
@@ -451,25 +483,27 @@ static NSString * const SQRLUpdaterUniqueTemporaryDirectoryPrefix = @"update.";
 				NSLog(@"Error enumerating item %@ within directory %@: %@", URL, directory, error);
 				return YES;
 			}];
-			
-			NSURL *updateBundleURL = [enumerator.rac_sequence objectPassingTest:^(NSURL *URL) {
-				NSString *type = nil;
-				NSError *error = nil;
-				if (![URL getResourceValue:&type forKey:NSURLTypeIdentifierKey error:&error]) {
-					NSLog(@"Error retrieving UTI for item at %@: %@", URL, error);
-					return NO;
-				}
 
-				if (!UTTypeConformsTo((__bridge CFStringRef)type, kUTTypeApplicationBundle)) return NO;
+			NSURL *updateBundleURL = [[enumerator.allObjects.rac_signal
+				filter:^(NSURL *URL) {
+					NSString *type = nil;
+					NSError *error = nil;
+					if (![URL getResourceValue:&type forKey:NSURLTypeIdentifierKey error:&error]) {
+						NSLog(@"Error retrieving UTI for item at %@: %@", URL, error);
+						return NO;
+					}
 
-				NSBundle *bundle = [NSBundle bundleWithURL:URL];
-				if (bundle == nil) {
-					NSLog(@"Could not open application bundle at %@", URL);
-					return NO;
-				}
+					if (!UTTypeConformsTo((__bridge CFStringRef)type, kUTTypeApplicationBundle)) return NO;
 
-				return [bundle.bundleIdentifier isEqual:NSRunningApplication.currentApplication.bundleIdentifier];
-			}];
+					NSBundle *bundle = [NSBundle bundleWithURL:URL];
+					if (bundle == nil) {
+						NSLog(@"Could not open application bundle at %@", URL);
+						return NO;
+					}
+
+					return [bundle.bundleIdentifier isEqual:NSRunningApplication.currentApplication.bundleIdentifier];
+				}]
+				first];
 
 			if (updateBundleURL != nil) {
 				return [RACSignal return:updateBundleURL];
@@ -504,14 +538,11 @@ static NSString * const SQRLUpdaterUniqueTemporaryDirectoryPrefix = @"update.";
 
 	return [[[[self.signature
 		verifyBundleAtURL:updateBundle.bundleURL]
-		then:^{
-			SQRLDownloadedUpdate *downloadedUpdate = [[SQRLDownloadedUpdate alloc] initWithUpdate:update bundle:updateBundle];
-			return [RACSignal return:downloadedUpdate];
-		}]
+		concat:[RACSignal return:[[SQRLDownloadedUpdate alloc] initWithUpdate:update bundle:updateBundle]]]
 		flattenMap:^(SQRLDownloadedUpdate *downloadedUpdate) {
-			return [[self prepareUpdateForInstallation:downloadedUpdate] then:^{
-				return [RACSignal return:downloadedUpdate];
-			}];
+			return [[self
+				prepareUpdateForInstallation:downloadedUpdate]
+				concat:[RACSignal return:downloadedUpdate]];
 		}]
 		setNameWithFormat:@"%@ -verifyAndPrepareUpdate: %@ fromBundle: %@", self, update, updateBundle];
 }
@@ -538,25 +569,24 @@ static NSString * const SQRLUpdaterUniqueTemporaryDirectoryPrefix = @"update.";
 - (RACSignal *)prepareUpdateForInstallation:(SQRLDownloadedUpdate *)update {
 	NSParameterAssert(update != nil);
 
-	return [[[[[[[SQRLShipItState
+	return [[[[[[[[SQRLShipItState
 		readUsingURL:self.shipItStateURL]
 		catchTo:[RACSignal empty]]
 		flattenMap:^(SQRLShipItState *existingState) {
 			return [self validateExistingState:existingState];
 		}]
-		then:^{
+		ignoreValues]
+		concat:[RACSignal defer:^{
 			SQRLShipItState *state = [[SQRLShipItState alloc] initWithTargetBundleURL:NSRunningApplication.currentApplication.bundleURL updateBundleURL:update.bundle.bundleURL bundleIdentifier:NSRunningApplication.currentApplication.bundleIdentifier codeSignature:self.signature];
 			return [state writeUsingURL:self.shipItStateURL];
-		}]
-		then:^{
-			return self.shipItLauncher;
-		}]
+		}]]
+		concat:self.shipItLauncher]
 		sqrl_addTransactionWithName:NSLocalizedString(@"Preparing update", nil) description:NSLocalizedString(@"An update for %@ is being prepared. Interrupting the process could corrupt the application.", nil), NSRunningApplication.currentApplication.bundleIdentifier]
 		setNameWithFormat:@"%@ -prepareUpdateForInstallation: %@", self, update];
 }
 
 - (RACSignal *)relaunchToInstallUpdate {
-	return [[[[[[[[SQRLShipItState
+	return [[[[[[[SQRLShipItState
 		readUsingURL:self.shipItStateURL]
 		flattenMap:^(SQRLShipItState *existingState) {
 			return [self validateExistingState:existingState];
@@ -574,7 +604,6 @@ static NSString * const SQRLUpdaterUniqueTemporaryDirectoryPrefix = @"update.";
 		// Never allow `completed` to escape this signal chain (in case
 		// -terminate: is asynchronous or something crazy).
 		concat:[RACSignal never]]
-		replay]
 		setNameWithFormat:@"%@ -relaunchToInstallUpdate", self];
 }
 

Squirrel/SQRLZipArchiver.m

@@ -130,25 +130,23 @@ const NSInteger SQRLZipArchiverShellTaskFailed = 1;
 		// This is important because the signals on `self` complete upon
 		// dealloc.
 		return:self]
-		then:^{
-			return [RACSignal
-				zip:@[ self.taskTerminated, self.standardErrorData ]
-				reduce:^(NSNumber *exitStatus, NSData *errorData) {
-					if (exitStatus.intValue == 0) return [RACSignal empty];
+		ignoreValues]
+		concat:[RACSignal
+			zip:@[ self.taskTerminated, self.standardErrorData ]
+			reduce:^(NSNumber *exitStatus, NSData *errorData) {
+				if (exitStatus.intValue == 0) return [RACSignal empty];
 
-					NSMutableDictionary *userInfo = [NSMutableDictionary dictionary];
-					userInfo[SQRLZipArchiverExitCodeErrorKey] = exitStatus;
+				NSMutableDictionary *userInfo = [NSMutableDictionary dictionary];
+				userInfo[SQRLZipArchiverExitCodeErrorKey] = exitStatus;
 
-					NSString *errorString = [[NSString alloc] initWithData:errorData encoding:NSUTF8StringEncoding];
-					errorString = [errorString stringByTrimmingCharactersInSet:NSCharacterSet.whitespaceAndNewlineCharacterSet];
-					if (errorString.length > 0) userInfo[NSLocalizedDescriptionKey] = errorString;
+				NSString *errorString = [[NSString alloc] initWithData:errorData encoding:NSUTF8StringEncoding];
+				errorString = [errorString stringByTrimmingCharactersInSet:NSCharacterSet.whitespaceAndNewlineCharacterSet];
+				if (errorString.length > 0) userInfo[NSLocalizedDescriptionKey] = errorString;
 
-					return [RACSignal error:[NSError errorWithDomain:SQRLZipArchiverErrorDomain code:SQRLZipArchiverShellTaskFailed userInfo:userInfo]];
-				}];
-		}]
+				return [RACSignal error:[NSError errorWithDomain:SQRLZipArchiverErrorDomain code:SQRLZipArchiverShellTaskFailed userInfo:userInfo]];
+			}]]
 		take:1]
 		flatten]
-		replay]
 		setNameWithFormat:@"-launchWithArguments: %@", arguments];
 
 	self.dittoTask.arguments = arguments;

Squirrel/ShipIt-main.m

@@ -55,16 +55,15 @@ int main(int argc, const char * argv[]) {
 		SQRLDirectoryManager *directoryManager = [[SQRLDirectoryManager alloc] initWithApplicationIdentifier:@(jobLabel)];
 		RACSignal *stateLocation = directoryManager.shipItStateURL;
 
-		[[[[[[SQRLShipItState
+		[[[[[[[SQRLShipItState
 			readUsingURL:stateLocation]
 			flattenMap:^(SQRLShipItState *state) {
 				return waitForTerminationIfNecessary(state);
 			}]
-			then:^{
-				// Read the latest state, in case it was modified by the
-				// controlling application in the meantime.
-				return [SQRLShipItState readUsingURL:stateLocation];
-			}]
+			ignoreValues]
+			// Read the latest state, in case it was modified by the
+			// controlling application in the meantime.
+			concat:[SQRLShipItState readUsingURL:stateLocation]]
 			catch:^(NSError *error) {
 				NSLog(@"Error reading saved installer state: %@", error);
 
@@ -79,10 +78,11 @@ int main(int argc, const char * argv[]) {
 				RACSignal *action;
 
 				if (attempt > SQRLShipItMaximumInstallationAttempts) {
-					action = [[[installer.abortInstallationCommand
-						execute:state]
-						initially:^{
+					action = [[RACSignal
+						defer:^{
 							NSLog(@"Too many attempts to install from state %i, aborting update", (int)state.installerState);
+
+							return [installer abortInstallationWithState:state];
 						}]
 						catch:^(NSError *error) {
 							NSLog(@"Error aborting installation: %@", error);
@@ -91,9 +91,8 @@ int main(int argc, const char * argv[]) {
 							return [RACSignal empty];
 						}];
 				} else {
-					action = [[[[[state
-						writeUsingURL:stateLocation]
-						initially:^{
+					action = [[[[RACSignal
+						defer:^{
 							if (freshInstall) {
 								NSLog(@"Beginning installation");
 								state.installerState = SQRLInstallerStateClearingQuarantine;
@@ -102,10 +101,10 @@ int main(int argc, const char * argv[]) {
 							}
 
 							state.installationStateAttempt = attempt;
+
+							return [state writeUsingURL:stateLocation];
 						}]
-						then:^{
-							return [installer.installUpdateCommand execute:state];
-						}]
+						concat:[installer installUpdateWithState:state]]
 						doCompleted:^{
 							NSLog(@"Installation completed successfully");
 						}]
@@ -117,7 +116,7 @@ int main(int argc, const char * argv[]) {
 					// fails.
 					action = [[action
 						deliverOn:RACScheduler.mainThreadScheduler]
-						finally:^{
+						doFinished:^{
 							NSURL *bundleURL = state.targetBundleURL;
 							if (bundleURL == nil) {
 								NSLog(@"Missing target bundle URL, cannot relaunch application");

SquirrelTests/SQRLInstallerSpec.m

@@ -77,7 +77,7 @@ it(@"should install an update in process", ^{
 	expect(installer).notTo.beNil();
 
 	NSError *installError = nil;
-	BOOL install = [[installer.installUpdateCommand execute:state] asynchronouslyWaitUntilCompleted:&installError];
+	BOOL install = [[installer installUpdateWithState:state] asynchronouslyWaitUntilCompleted:&installError];
 	expect(install).to.beTruthy();
 	expect(installError).to.beNil();
 });

SquirrelTests/SQRLTestCase.m

@@ -53,7 +53,7 @@ static void SQRLSignalHandler(int sig) {
 
 // Returns an _unlaunched_ task that will follow log files at the given paths,
 // then pipe that output through this process.
-+ (NSTask *)tailTaskWithPaths:(RACSequence *)paths;
++ (NSTask *)tailTaskWithPaths:(RACSignal *)paths;
 
 @end
 
@@ -75,23 +75,24 @@ static void SQRLSignalHandler(int sig) {
 		@"otest-x86_64.ShipIt",
 	];
 
-	RACSequence *URLs = [folders.rac_sequence flattenMap:^(NSString *folder) {
-		NSURL *baseURL = [appSupportURL URLByAppendingPathComponent:folder];
-		return @[
-			[baseURL URLByAppendingPathComponent:@"ShipIt_stdout.log"],
-			[baseURL URLByAppendingPathComponent:@"ShipIt_stderr.log"]
-		].rac_sequence;
-	}];
+	RACSignal *logLocations = [[[[folders.rac_signal
+		flattenMap:^(NSString *folder) {
+			return [folder stringsByAppendingPaths:@[
+				@"ShipIt_stdout.log",
+				@"ShipIt_stderr.log",
+			]].rac_signal;
+		}]
+		map:^(NSString *path) {
+			return [appSupportURL URLByAppendingPathComponent:path];
+		}]
+		doNext:^(NSURL *location) {
+			[[NSData data] writeToURL:location atomically:YES];
+		}]
+		map:^(NSURL *location) {
+			return location.path;
+		}];
 
-	for (NSURL *URL in URLs) {
-		[[NSData data] writeToURL:URL atomically:YES];
-	}
-
-	RACSequence *paths = [URLs map:^(NSURL *URL) {
-		return URL.path;
-	}];
-
-	NSTask *readShipIt = [self tailTaskWithPaths:paths];
+	NSTask *readShipIt = [self tailTaskWithPaths:logLocations];
 	[readShipIt launch];
 
 	NSAssert([readShipIt isRunning], @"Could not start task %@", readShipIt);
@@ -136,7 +137,7 @@ static void SQRLSignalHandler(int sig) {
 
 #pragma mark Logging
 
-+ (NSTask *)tailTaskWithPaths:(RACSequence *)paths {
++ (NSTask *)tailTaskWithPaths:(RACSignal *)paths {
 	NSPipe *outputPipe = [NSPipe pipe];
 	NSFileHandle *outputHandle = outputPipe.fileHandleForReading;
 
@@ -197,7 +198,7 @@ static void SQRLSignalHandler(int sig) {
 		NSURL *testAppLog = [fixtureURL.URLByDeletingLastPathComponent URLByAppendingPathComponent:@"TestApplication.log"];
 		[[NSData data] writeToURL:testAppLog atomically:YES];
 
-		NSTask *readTestApp = [self.class tailTaskWithPaths:[RACSequence return:testAppLog.path]];
+		NSTask *readTestApp = [self.class tailTaskWithPaths:[RACSignal return:testAppLog.path]];
 		[readTestApp launch];
 
 		STAssertTrue([readTestApp isRunning], @"Could not start task %@ to read %@", readTestApp, testAppLog);

SquirrelTests/SQRLUpdaterSpec.m

@@ -154,7 +154,7 @@ describe(@"updating", ^{
 					NSArray *contents = [NSFileManager.defaultManager contentsOfDirectoryAtURL:appSupportURL includingPropertiesForKeys:nil options:0 error:NULL];
 					if (contents == nil) return [RACSignal empty];
 
-					return contents.rac_sequence.signal;
+					return contents.rac_signal;
 				}]
 				filter:^(NSURL *directoryURL) {
 					return [directoryURL.lastPathComponent hasPrefix:@"update."];
@@ -179,7 +179,7 @@ describe(@"updating", ^{
 
 			// Also test that this is the only update directory (any others
 			// should've been removed).
-			NSArray *directoryURLs = [updateDirectoryURLs toArray];
+			NSArray *directoryURLs = [updateDirectoryURLs array];
 			expect(directoryURLs.count).to.equal(1);
 
 			NSArray *contents = [NSFileManager.defaultManager contentsOfDirectoryAtURL:directoryURLs[0] includingPropertiesForKeys:nil options:NSDirectoryEnumerationSkipsHiddenFiles error:NULL];
@@ -208,7 +208,7 @@ describe(@"response handling", ^{
 		}];
 
 		NSError *error = nil;
-		BOOL result = [[updater.checkForUpdatesCommand execute:nil] asynchronouslyWaitUntilCompleted:&error];
+		BOOL result = [[updater.checkForUpdatesAction signalWithValue:nil] asynchronouslyWaitUntilCompleted:&error];
 		expect(result).to.beFalsy();
 		expect(error.domain).to.equal(SQRLUpdaterErrorDomain);
 		expect(error.code).to.equal(SQRLUpdaterErrorInvalidServerResponse);
@@ -225,7 +225,7 @@ describe(@"response handling", ^{
 		}];
 
 		NSError *error = nil;
-		BOOL result = [[updater.checkForUpdatesCommand execute:nil] asynchronouslyWaitUntilCompleted:&error];
+		BOOL result = [[updater.checkForUpdatesAction signalWithValue:nil] asynchronouslyWaitUntilCompleted:&error];
 		expect(result).to.beFalsy();
 		expect(error.domain).to.equal(SQRLUpdaterErrorDomain);
 		expect(error.code).to.equal(SQRLUpdaterErrorInvalidServerBody);

TestApplication/TestAppDelegate.m

@@ -70,18 +70,18 @@
 			NSLog(@"***** UPDATE CHECK %lu *****", (unsigned long)updateCheckCount);
 			updateCheckCount++;
 
-			return [self.updater.checkForUpdatesCommand execute:RACUnit.defaultUnit];
+			return [self.updater.checkForUpdatesAction signalWithValue:nil];
 		}]
 		doNext:^(SQRLDownloadedUpdate *update) {
 			NSLog(@"Got a candidate update: %@", update);
 		}]
 		// Retry until we get the expected release.
 		repeat]
-		skipUntilBlock:^(SQRLDownloadedUpdate *download) {
+		skipWhile:^ BOOL (SQRLDownloadedUpdate *download) {
 			SQRLTestUpdate *testUpdate = (id)download.update;
 			NSAssert([testUpdate isKindOfClass:SQRLTestUpdate.class], @"Unexpected update type: %@", testUpdate);
 
-			return testUpdate.final;
+			return !testUpdate.final;
 		}]
 		take:1]
 		doNext:^(id _) {
@@ -92,12 +92,12 @@
 			NSLog(@"Error in updater: %@", error);
 			return [RACSignal empty];
 		}]
-		then:^{
+		concat:[RACSignal defer:^{
 			NSString *delayString = NSProcessInfo.processInfo.environment[@"SQRLUpdateDelay"];
 			if (delayString == nil) return [RACSignal empty];
 
 			return [[RACSignal interval:delayString.doubleValue onScheduler:RACScheduler.mainThreadScheduler] take:1];
-		}]
+		}]]
 		subscribeCompleted:^{
 			[NSApp terminate:self];
 		}];