[camera_avfoundation] Implementation swift migration - part 11 (#9690)

Migrates camera implementation as part of flutter/flutter#119109

Resolves flutter/flutter#170439. This PR migrates the last one of the problematic methods (`startImageStream`) to Switft, which resolves the issue.

This PR migrates the 8th chunk of `FLTCam` class to Swift:
* `startImageStream`
* `setUpCaptureSessionForAudioIfNeeded`
* `reportErrorMessage` (ObjC implementation removal)

Some properties of the FLTCam have to be temporarily made public so that they are accessible in DefaultCamera.

## Pre-Review Checklist

**Note**: The Flutter team is currently trialing the use of [Gemini Code Assist for GitHub](https://developers.google.com/gemini-code-assist/docs/review-github-code). Comments from the `gemini-code-assist` bot should not be taken as authoritative feedback from the Flutter team. If you find its comments useful you can update your code accordingly, but if you are unsure or disagree with the feedback, please feel free to wait for a Flutter team member's review for guidance on which automated comments should be addressed.

[^1]: Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling.

Author: RobertOdrowaz

packages/camera/camera_avfoundation/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.9.21+1
+
+* Migrates `startImageStream` and `setUpCaptureSessionForAudioIfNeeded` methods to Swift.
+* Removes Objective-C implementation of `reportErrorMessage` method.
+
 ## 0.9.21
 
 * Fixes crash when streaming is enabled during recording.

packages/camera/camera_avfoundation/ios/camera_avfoundation/Sources/camera_avfoundation/DefaultCamera.swift

@@ -92,6 +92,92 @@ final class DefaultCamera: FLTCam, Camera {
     return (captureVideoInput, captureVideoOutput, connection)
   }
 
+  func setUpCaptureSessionForAudioIfNeeded() {
+    // Don't setup audio twice or we will lose the audio.
+    guard !mediaSettings.enableAudio || !isAudioSetup else { return }
+
+    let audioDevice = audioCaptureDeviceFactory()
+    do {
+      // Create a device input with the device and add it to the session.
+      // Setup the audio input.
+      let audioInput = try captureDeviceInputFactory.deviceInput(with: audioDevice)
+
+      // Setup the audio output.
+      let audioOutput = AVCaptureAudioDataOutput()
+
+      let block = {
+        // Set up options implicit to AVAudioSessionCategoryPlayback to avoid conflicts with other
+        // plugins like video_player.
+        DefaultCamera.upgradeAudioSessionCategory(
+          requestedCategory: .playAndRecord,
+          options: [.defaultToSpeaker, .allowBluetoothA2DP, .allowAirPlay]
+        )
+      }
+
+      if !Thread.isMainThread {
+        DispatchQueue.main.sync(execute: block)
+      } else {
+        block()
+      }
+
+      if audioCaptureSession.canAddInput(audioInput) {
+        audioCaptureSession.addInput(audioInput)
+
+        if audioCaptureSession.canAddOutput(audioOutput) {
+          audioCaptureSession.addOutput(audioOutput)
+          audioOutput.setSampleBufferDelegate(self, queue: captureSessionQueue)
+          isAudioSetup = true
+        } else {
+          reportErrorMessage("Unable to add Audio input/output to session capture")
+          isAudioSetup = false
+        }
+      }
+    } catch let error as NSError {
+      reportErrorMessage(error.description)
+    }
+  }
+
+  // This function, although slightly modified, is also in video_player_avfoundation (in ObjC).
+  // Both need to do the same thing and run on the same thread (for example main thread).
+  // Configure application wide audio session manually to prevent overwriting flag
+  // MixWithOthers by capture session.
+  // Only change category if it is considered an upgrade which means it can only enable
+  // ability to play in silent mode or ability to record audio but never disables it,
+  // that could affect other plugins which depend on this global state. Only change
+  // category or options if there is change to prevent unnecessary lags and silence.
+  private static func upgradeAudioSessionCategory(
+    requestedCategory: AVAudioSession.Category,
+    options: AVAudioSession.CategoryOptions
+  ) {
+    let playCategories: Set<AVAudioSession.Category> = [.playback, .playAndRecord]
+    let recordCategories: Set<AVAudioSession.Category> = [.record, .playAndRecord]
+    let requiredCategories: Set<AVAudioSession.Category> = [
+      requestedCategory, AVAudioSession.sharedInstance().category,
+    ]
+
+    let requiresPlay = !requiredCategories.isDisjoint(with: playCategories)
+    let requiresRecord = !requiredCategories.isDisjoint(with: recordCategories)
+
+    var finalCategory = requestedCategory
+    if requiresPlay && requiresRecord {
+      finalCategory = .playAndRecord
+    } else if requiresPlay {
+      finalCategory = .playback
+    } else if requiresRecord {
+      finalCategory = .record
+    }
+
+    let finalOptions = AVAudioSession.sharedInstance().categoryOptions.union(options)
+
+    if finalCategory == AVAudioSession.sharedInstance().category
+      && finalOptions == AVAudioSession.sharedInstance().categoryOptions
+    {
+      return
+    }
+
+    try? AVAudioSession.sharedInstance().setCategory(finalCategory, options: finalOptions)
+  }
+
   func reportInitializationState() {
     // Get all the state on the current thread, not the main thread.
     let state = FCPPlatformCameraState.make(
@@ -257,7 +343,6 @@ final class DefaultCamera: FLTCam, Camera {
       newAudioWriterInput.expectsMediaDataInRealTime = true
       mediaSettingsAVWrapper.addInput(newAudioWriterInput, to: videoWriter)
       self.audioWriterInput = newAudioWriterInput
-      audioOutput.setSampleBufferDelegate(self, queue: captureSessionQueue)
     }
 
     if flashMode == .torch {
@@ -728,6 +813,53 @@ final class DefaultCamera: FLTCam, Camera {
     completion(nil)
   }
 
+  func startImageStream(
+    with messenger: any FlutterBinaryMessenger, completion: @escaping (FlutterError?) -> Void
+  ) {
+    startImageStream(
+      with: messenger,
+      imageStreamHandler: FLTImageStreamHandler(captureSessionQueue: captureSessionQueue),
+      completion: completion
+    )
+  }
+
+  func startImageStream(
+    with messenger: FlutterBinaryMessenger,
+    imageStreamHandler: FLTImageStreamHandler,
+    completion: @escaping (FlutterError?) -> Void
+  ) {
+    if isStreamingImages {
+      reportErrorMessage("Images from camera are already streaming!")
+      completion(nil)
+      return
+    }
+
+    let eventChannel = FlutterEventChannel(
+      name: "plugins.flutter.io/camera_avfoundation/imageStream",
+      binaryMessenger: messenger
+    )
+    let threadSafeEventChannel = FLTThreadSafeEventChannel(eventChannel: eventChannel)
+
+    self.imageStreamHandler = imageStreamHandler
+    threadSafeEventChannel.setStreamHandler(imageStreamHandler) { [weak self] in
+      guard let strongSelf = self else {
+        completion(nil)
+        return
+      }
+
+      strongSelf.captureSessionQueue.async { [weak self] in
+        guard let strongSelf = self else {
+          completion(nil)
+          return
+        }
+
+        strongSelf.isStreamingImages = true
+        strongSelf.streamingPendingFramesCount = 0
+        completion(nil)
+      }
+    }
+  }
+
   func stopImageStream() {
     if isStreamingImages {
       isStreamingImages = false
@@ -989,6 +1121,9 @@ final class DefaultCamera: FLTCam, Camera {
     }
   }
 
+  /// Reports the given error message to the Dart side of the plugin.
+  ///
+  /// Can be called from any thread.
   private func reportErrorMessage(_ errorMessage: String) {
     FLTEnsureToRunOnMainQueue { [weak self] in
       self?.dartAPI?.reportError(errorMessage) { _ in

packages/camera/camera_avfoundation/ios/camera_avfoundation/Sources/camera_avfoundation_objc/FLTCam.m

@@ -28,17 +28,11 @@ @interface FLTCam () <AVCaptureVideoDataOutputSampleBufferDelegate,
 @property(strong, nonatomic)
     NSObject<FLTAssetWriterInputPixelBufferAdaptor> *assetWriterPixelBufferAdaptor;
 @property(strong, nonatomic) AVCaptureVideoDataOutput *videoOutput;
-@property(assign, nonatomic) BOOL isAudioSetup;
 
 /// A wrapper for CMVideoFormatDescriptionGetDimensions.
 /// Allows for alternate implementations in tests.
 @property(nonatomic, copy) VideoDimensionsForFormat videoDimensionsForFormat;
-/// A wrapper for AVCaptureDevice creation to allow for dependency injection in tests.
-@property(nonatomic, copy) AudioCaptureDeviceFactory audioCaptureDeviceFactory;
-/// Reports the given error message to the Dart side of the plugin.
-///
-/// Can be called from any thread.
-- (void)reportErrorMessage:(NSString *)errorMessage;
+
 @end
 
 @implementation FLTCam
@@ -308,139 +302,4 @@ - (BOOL)setCaptureSessionPreset:(FCPPlatformResolutionPreset)resolutionPreset
   return bestFormat;
 }
 
-- (void)startImageStreamWithMessenger:(NSObject<FlutterBinaryMessenger> *)messenger
-                           completion:(void (^)(FlutterError *))completion {
-  [self startImageStreamWithMessenger:messenger
-                   imageStreamHandler:[[FLTImageStreamHandler alloc]
-                                          initWithCaptureSessionQueue:_captureSessionQueue]
-                           completion:completion];
-}
-
-- (void)startImageStreamWithMessenger:(NSObject<FlutterBinaryMessenger> *)messenger
-                   imageStreamHandler:(FLTImageStreamHandler *)imageStreamHandler
-                           completion:(void (^)(FlutterError *))completion {
-  if (!_isStreamingImages) {
-    id<FLTEventChannel> eventChannel = [FlutterEventChannel
-        eventChannelWithName:@"plugins.flutter.io/camera_avfoundation/imageStream"
-             binaryMessenger:messenger];
-    FLTThreadSafeEventChannel *threadSafeEventChannel =
-        [[FLTThreadSafeEventChannel alloc] initWithEventChannel:eventChannel];
-
-    _imageStreamHandler = imageStreamHandler;
-    __weak typeof(self) weakSelf = self;
-    [threadSafeEventChannel setStreamHandler:_imageStreamHandler
-                                  completion:^{
-                                    typeof(self) strongSelf = weakSelf;
-                                    if (!strongSelf) {
-                                      completion(nil);
-                                      return;
-                                    }
-
-                                    dispatch_async(strongSelf.captureSessionQueue, ^{
-                                      // cannot use the outter strongSelf
-                                      typeof(self) strongSelf = weakSelf;
-                                      if (!strongSelf) {
-                                        completion(nil);
-                                        return;
-                                      }
-
-                                      strongSelf.isStreamingImages = YES;
-                                      strongSelf.streamingPendingFramesCount = 0;
-                                      completion(nil);
-                                    });
-                                  }];
-  } else {
-    [self reportErrorMessage:@"Images from camera are already streaming!"];
-    completion(nil);
-  }
-}
-
-// This function, although slightly modified, is also in video_player_avfoundation.
-// Both need to do the same thing and run on the same thread (for example main thread).
-// Configure application wide audio session manually to prevent overwriting flag
-// MixWithOthers by capture session.
-// Only change category if it is considered an upgrade which means it can only enable
-// ability to play in silent mode or ability to record audio but never disables it,
-// that could affect other plugins which depend on this global state. Only change
-// category or options if there is change to prevent unnecessary lags and silence.
-static void upgradeAudioSessionCategory(AVAudioSessionCategory requestedCategory,
-                                        AVAudioSessionCategoryOptions options) {
-  NSSet *playCategories = [NSSet
-      setWithObjects:AVAudioSessionCategoryPlayback, AVAudioSessionCategoryPlayAndRecord, nil];
-  NSSet *recordCategories =
-      [NSSet setWithObjects:AVAudioSessionCategoryRecord, AVAudioSessionCategoryPlayAndRecord, nil];
-  NSSet *requiredCategories =
-      [NSSet setWithObjects:requestedCategory, AVAudioSession.sharedInstance.category, nil];
-  BOOL requiresPlay = [requiredCategories intersectsSet:playCategories];
-  BOOL requiresRecord = [requiredCategories intersectsSet:recordCategories];
-  if (requiresPlay && requiresRecord) {
-    requestedCategory = AVAudioSessionCategoryPlayAndRecord;
-  } else if (requiresPlay) {
-    requestedCategory = AVAudioSessionCategoryPlayback;
-  } else if (requiresRecord) {
-    requestedCategory = AVAudioSessionCategoryRecord;
-  }
-  options = AVAudioSession.sharedInstance.categoryOptions | options;
-  if ([requestedCategory isEqualToString:AVAudioSession.sharedInstance.category] &&
-      options == AVAudioSession.sharedInstance.categoryOptions) {
-    return;
-  }
-  [AVAudioSession.sharedInstance setCategory:requestedCategory withOptions:options error:nil];
-}
-
-- (void)setUpCaptureSessionForAudioIfNeeded {
-  // Don't setup audio twice or we will lose the audio.
-  if (!_mediaSettings.enableAudio || _isAudioSetup) {
-    return;
-  }
-
-  NSError *error = nil;
-  // Create a device input with the device and add it to the session.
-  // Setup the audio input.
-  NSObject<FLTCaptureDevice> *audioDevice = self.audioCaptureDeviceFactory();
-  NSObject<FLTCaptureInput> *audioInput =
-      [_captureDeviceInputFactory deviceInputWithDevice:audioDevice error:&error];
-  if (error) {
-    [self reportErrorMessage:error.description];
-  }
-  // Setup the audio output.
-  _audioOutput = [[AVCaptureAudioDataOutput alloc] init];
-
-  dispatch_block_t block = ^{
-    // Set up options implicit to AVAudioSessionCategoryPlayback to avoid conflicts with other
-    // plugins like video_player.
-    upgradeAudioSessionCategory(AVAudioSessionCategoryPlayAndRecord,
-                                AVAudioSessionCategoryOptionDefaultToSpeaker |
-                                    AVAudioSessionCategoryOptionAllowBluetoothA2DP |
-                                    AVAudioSessionCategoryOptionAllowAirPlay);
-  };
-  if (!NSThread.isMainThread) {
-    dispatch_sync(dispatch_get_main_queue(), block);
-  } else {
-    block();
-  }
-
-  if ([_audioCaptureSession canAddInput:audioInput]) {
-    [_audioCaptureSession addInput:audioInput];
-
-    if ([_audioCaptureSession canAddOutput:_audioOutput]) {
-      [_audioCaptureSession addOutput:_audioOutput];
-      _isAudioSetup = YES;
-    } else {
-      [self reportErrorMessage:@"Unable to add Audio input/output to session capture"];
-      _isAudioSetup = NO;
-    }
-  }
-}
-
-- (void)reportErrorMessage:(NSString *)errorMessage {
-  __weak typeof(self) weakSelf = self;
-  FLTEnsureToRunOnMainQueue(^{
-    [weakSelf.dartAPI reportError:errorMessage
-                       completion:^(FlutterError *error){
-                           // Ignore any errors, as this is just an event broadcast.
-                       }];
-  });
-}
-
 @end

packages/camera/camera_avfoundation/ios/camera_avfoundation/Sources/camera_avfoundation_objc/include/camera_avfoundation/FLTCam.h

@@ -64,16 +64,14 @@ NS_ASSUME_NONNULL_BEGIN
 @property(readonly, nonatomic) FLTCamMediaSettingsAVWrapper *mediaSettingsAVWrapper;
 @property(readonly, nonatomic) FCPPlatformMediaSettings *mediaSettings;
 @property(nonatomic, copy) InputPixelBufferAdaptorFactory inputPixelBufferAdaptorFactory;
-@property(strong, nonatomic) AVCaptureAudioDataOutput *audioOutput;
+@property(assign, nonatomic) BOOL isAudioSetup;
+/// A wrapper for AVCaptureDevice creation to allow for dependency injection in tests.
+@property(nonatomic, copy) AudioCaptureDeviceFactory audioCaptureDeviceFactory;
 
 /// Initializes an `FLTCam` instance with the given configuration.
 /// @param error report to the caller if any error happened creating the camera.
 - (instancetype)initWithConfiguration:(FLTCamConfiguration *)configuration error:(NSError **)error;
 
-- (void)startImageStreamWithMessenger:(NSObject<FlutterBinaryMessenger> *)messenger
-                           completion:(nonnull void (^)(FlutterError *_Nullable))completion;
-- (void)setUpCaptureSessionForAudioIfNeeded;
-
 // Methods exposed for the Swift DefaultCamera subclass
 - (void)updateOrientation;
 

packages/camera/camera_avfoundation/ios/camera_avfoundation/Sources/camera_avfoundation_objc/include/camera_avfoundation/FLTCam_Test.h

@@ -31,9 +31,4 @@
 @property(readonly, nonatomic)
     NSMutableDictionary<NSNumber *, FLTSavePhotoDelegate *> *inProgressSavePhotoDelegates;
 
-/// Start streaming images.
-- (void)startImageStreamWithMessenger:(NSObject<FlutterBinaryMessenger> *)messenger
-                   imageStreamHandler:(FLTImageStreamHandler *)imageStreamHandler
-                           completion:(void (^)(FlutterError *))completion;
-
 @end

packages/camera/camera_avfoundation/pubspec.yaml

@@ -2,7 +2,7 @@ name: camera_avfoundation
 description: iOS implementation of the camera plugin.
 repository: https://github.com/flutter/packages/tree/main/packages/camera/camera_avfoundation
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+camera%22
-version: 0.9.21
+version: 0.9.21+1
 
 environment:
   sdk: ^3.6.0