[camera_avfoundation] Implementation swift migration - part 10 (#9664)

Migrates camera implementation as part of flutter/flutter#119109

This PR migrates the 7th chunk of `FLTCam` class to Swift:
* `captureToFile`
* `getTemporaryFilePath`

We can also finally switch to Swift interface for dispatch queue specific because all usages are now in Swift.

## Pre-Review Checklist

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Author: RobertOdrowaz

packages/camera/camera_avfoundation/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.9.20+6
+
+* Migrates `captureToFile` and `getTemporaryFilePath` methods to Swift.
+* Switches to Swift dispatch queue specific interface.
+
 ## 0.9.20+5
 
 * Migrates `startVideoRecording`, `setUpVideoRecording`, and `setupWriter` methods to Swift.

packages/camera/camera_avfoundation/example/ios/RunnerTests/PhotoCaptureTests.swift

@@ -24,7 +24,8 @@ final class PhotoCaptureTests: XCTestCase {
     let errorExpectation = expectation(
       description: "Must send error to result if save photo delegate completes with error.")
     let captureSessionQueue = DispatchQueue(label: "capture_session_queue")
-    FLTDispatchQueueSetSpecific(captureSessionQueue, FLTCaptureSessionQueueSpecific)
+    captureSessionQueue.setSpecific(
+      key: captureSessionQueueSpecificKey, value: captureSessionQueueSpecificValue)
     let cam = createCam(with: captureSessionQueue)
     let error = NSError(domain: "test", code: 0, userInfo: nil)
 
@@ -57,7 +58,8 @@ final class PhotoCaptureTests: XCTestCase {
     let pathExpectation = expectation(
       description: "Must send file path to result if save photo delegate completes with file path.")
     let captureSessionQueue = DispatchQueue(label: "capture_session_queue")
-    FLTDispatchQueueSetSpecific(captureSessionQueue, FLTCaptureSessionQueueSpecific)
+    captureSessionQueue.setSpecific(
+      key: captureSessionQueueSpecificKey, value: captureSessionQueueSpecificValue)
     let cam = createCam(with: captureSessionQueue)
     let filePath = "test"
 
@@ -90,7 +92,8 @@ final class PhotoCaptureTests: XCTestCase {
       description: "Test must set extension to heif if availablePhotoCodecTypes contains HEVC.")
 
     let captureSessionQueue = DispatchQueue(label: "capture_session_queue")
-    FLTDispatchQueueSetSpecific(captureSessionQueue, FLTCaptureSessionQueueSpecific)
+    captureSessionQueue.setSpecific(
+      key: captureSessionQueueSpecificKey, value: captureSessionQueueSpecificValue)
     let cam = createCam(with: captureSessionQueue)
     cam.setImageFileFormat(FCPPlatformImageFileFormat.heif)
 
@@ -125,7 +128,8 @@ final class PhotoCaptureTests: XCTestCase {
         "Test must set extension to jpg if availablePhotoCodecTypes does not contain HEVC.")
 
     let captureSessionQueue = DispatchQueue(label: "capture_session_queue")
-    FLTDispatchQueueSetSpecific(captureSessionQueue, FLTCaptureSessionQueueSpecific)
+    captureSessionQueue.setSpecific(
+      key: captureSessionQueueSpecificKey, value: captureSessionQueueSpecificValue)
     let cam = createCam(with: captureSessionQueue)
     cam.setImageFileFormat(FCPPlatformImageFileFormat.heif)
 
@@ -170,7 +174,8 @@ final class PhotoCaptureTests: XCTestCase {
     }
 
     let captureSessionQueue = DispatchQueue(label: "capture_session_queue")
-    FLTDispatchQueueSetSpecific(captureSessionQueue, FLTCaptureSessionQueueSpecific)
+    captureSessionQueue.setSpecific(
+      key: captureSessionQueueSpecificKey, value: captureSessionQueueSpecificValue)
     let configuration = CameraTestUtils.createTestCameraConfiguration()
     configuration.captureSessionQueue = captureSessionQueue
     configuration.captureDeviceFactory = { _ in captureDeviceMock }

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

@@ -69,7 +69,8 @@ public final class CameraPlugin: NSObject, FlutterPlugin {
 
     super.init()
 
-    FLTDispatchQueueSetSpecific(captureSessionQueue, FLTCaptureSessionQueueSpecific)
+    captureSessionQueue.setSpecific(
+      key: captureSessionQueueSpecificKey, value: captureSessionQueueSpecificValue)
 
     UIDevice.current.beginGeneratingDeviceOrientationNotifications()
     NotificationCenter.default.addObserver(

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

@@ -38,6 +38,10 @@ final class DefaultCamera: FLTCam, Camera {
   private let pixelBufferSynchronizationQueue = DispatchQueue(
     label: "io.flutter.camera.pixelBufferSynchronizationQueue")
 
+  /// The queue on which captured photos (not videos) are written to disk.
+  /// Videos are written to disk by `videoAdaptor` on an internal queue managed by AVFoundation.
+  private let photoIOQueue = DispatchQueue(label: "io.flutter.camera.photoIOQueue")
+
   /// Tracks the latest pixel buffer sent from AVFoundation's sample buffer delegate callback.
   /// Used to deliver the latest pixel buffer to the flutter engine via the `copyPixelBuffer` API.
   private var latestPixelBuffer: CVPixelBuffer?
@@ -313,6 +317,93 @@ final class DefaultCamera: FLTCam, Camera {
     }
   }
 
+  func captureToFile(completion: @escaping (String?, FlutterError?) -> Void) {
+    var settings = AVCapturePhotoSettings()
+
+    if mediaSettings.resolutionPreset == .max {
+      settings.isHighResolutionPhotoEnabled = true
+    }
+
+    let fileExtension: String
+
+    let isHEVCCodecAvailable = capturePhotoOutput.availablePhotoCodecTypes.contains(
+      .hevc)
+
+    if fileFormat == .heif, isHEVCCodecAvailable {
+      settings = AVCapturePhotoSettings(format: [AVVideoCodecKey: AVVideoCodecType.hevc])
+      fileExtension = "heif"
+    } else {
+      fileExtension = "jpg"
+    }
+
+    if flashMode != .torch {
+      settings.flashMode = FCPGetAVCaptureFlashModeForPigeonFlashMode(flashMode)
+    }
+
+    let path: String
+    do {
+      path = try getTemporaryFilePath(
+        withExtension: fileExtension,
+        subfolder: "pictures",
+        prefix: "CAP_")
+    } catch let error as NSError {
+      completion(nil, DefaultCamera.flutterErrorFromNSError(error))
+      return
+    }
+
+    let savePhotoDelegate = FLTSavePhotoDelegate(
+      path: path,
+      ioQueue: photoIOQueue,
+      completionHandler: { [weak self] path, error in
+        guard let strongSelf = self else { return }
+
+        strongSelf.captureSessionQueue.async { [weak self] in
+          self?.inProgressSavePhotoDelegates.removeObject(
+            forKey: settings.uniqueID)
+        }
+
+        if let error = error {
+          completion(nil, DefaultCamera.flutterErrorFromNSError(error as NSError))
+        } else {
+          assert(path != nil, "Path must not be nil if no error.")
+          completion(path, nil)
+        }
+      }
+    )
+
+    assert(
+      DispatchQueue.getSpecific(key: captureSessionQueueSpecificKey)
+        == captureSessionQueueSpecificValue,
+      "save photo delegate references must be updated on the capture session queue")
+    inProgressSavePhotoDelegates[settings.uniqueID] = savePhotoDelegate
+    capturePhotoOutput.capturePhoto(with: settings, delegate: savePhotoDelegate)
+  }
+
+  private func getTemporaryFilePath(
+    withExtension ext: String,
+    subfolder: String,
+    prefix: String
+  ) throws -> String {
+    let documentDirectory = FileManager.default.urls(
+      for: .documentDirectory,
+      in: .userDomainMask)[0]
+
+    let fileDirectory = documentDirectory.appendingPathComponent("camera").appendingPathComponent(
+      subfolder)
+    let fileName = prefix + UUID().uuidString
+    let file = fileDirectory.appendingPathComponent(fileName).appendingPathExtension(ext).path
+
+    let fileManager = FileManager.default
+    if !fileManager.fileExists(atPath: fileDirectory.path) {
+      try fileManager.createDirectory(
+        at: fileDirectory,
+        withIntermediateDirectories: true,
+        attributes: nil)
+    }
+
+    return file
+  }
+
   func lockCaptureOrientation(_ pigeonOrientation: FCPPlatformDeviceOrientation) {
     let orientation = FCPGetUIDeviceOrientationForPigeonDeviceOrientation(pigeonOrientation)
     if lockedCaptureOrientation != orientation {

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

@@ -0,0 +1,9 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import Dispatch
+
+/// Queue-specific context data to be associated with the capture session queue.
+let captureSessionQueueSpecificKey = DispatchSpecificKey<String>()
+let captureSessionQueueSpecificValue = "capture_session_queue"

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

@@ -19,12 +19,6 @@
 #import "./include/camera_avfoundation/QueueUtils.h"
 #import "./include/camera_avfoundation/messages.g.h"
 
-static FlutterError *FlutterErrorFromNSError(NSError *error) {
-  return [FlutterError errorWithCode:[NSString stringWithFormat:@"Error %d", (int)error.code]
-                             message:error.localizedDescription
-                             details:error.domain];
-}
-
 @interface FLTCam () <AVCaptureVideoDataOutputSampleBufferDelegate,
                       AVCaptureAudioDataOutputSampleBufferDelegate>
 
@@ -36,9 +30,6 @@ @interface FLTCam () <AVCaptureVideoDataOutputSampleBufferDelegate,
 @property(strong, nonatomic) AVCaptureVideoDataOutput *videoOutput;
 @property(assign, nonatomic) BOOL isAudioSetup;
 
-/// The queue on which captured photos (not videos) are written to disk.
-/// Videos are written to disk by `videoAdaptor` on an internal queue managed by AVFoundation.
-@property(strong, nonatomic) dispatch_queue_t photoIOQueue;
 /// A wrapper for CMVideoFormatDescriptionGetDimensions.
 /// Allows for alternate implementations in tests.
 @property(nonatomic, copy) VideoDimensionsForFormat videoDimensionsForFormat;
@@ -62,7 +53,6 @@ - (instancetype)initWithConfiguration:(nonnull FLTCamConfiguration *)configurati
   _mediaSettingsAVWrapper = configuration.mediaSettingsWrapper;
 
   _captureSessionQueue = configuration.captureSessionQueue;
-  _photoIOQueue = dispatch_queue_create("io.flutter.camera.photoIOQueue", NULL);
   _videoCaptureSession = configuration.videoCaptureSession;
   _audioCaptureSession = configuration.audioCaptureSession;
   _captureDeviceFactory = configuration.captureDeviceFactory;
@@ -206,69 +196,6 @@ - (void)updateOrientation:(UIDeviceOrientation)orientation
   }
 }
 
-- (void)captureToFileWithCompletion:(void (^)(NSString *_Nullable,
-                                              FlutterError *_Nullable))completion {
-  AVCapturePhotoSettings *settings = [AVCapturePhotoSettings photoSettings];
-
-  if (self.mediaSettings.resolutionPreset == FCPPlatformResolutionPresetMax) {
-    [settings setHighResolutionPhotoEnabled:YES];
-  }
-
-  NSString *extension;
-
-  BOOL isHEVCCodecAvailable =
-      [self.capturePhotoOutput.availablePhotoCodecTypes containsObject:AVVideoCodecTypeHEVC];
-
-  if (_fileFormat == FCPPlatformImageFileFormatHeif && isHEVCCodecAvailable) {
-    settings =
-        [AVCapturePhotoSettings photoSettingsWithFormat:@{AVVideoCodecKey : AVVideoCodecTypeHEVC}];
-    extension = @"heif";
-  } else {
-    extension = @"jpg";
-  }
-
-  // If the flash is in torch mode, no capture-level flash setting is needed.
-  if (self.flashMode != FCPPlatformFlashModeTorch) {
-    [settings setFlashMode:FCPGetAVCaptureFlashModeForPigeonFlashMode(self.flashMode)];
-  }
-  NSError *error;
-  NSString *path = [self getTemporaryFilePathWithExtension:extension
-                                                 subfolder:@"pictures"
-                                                    prefix:@"CAP_"
-                                                     error:&error];
-  if (error) {
-    completion(nil, FlutterErrorFromNSError(error));
-    return;
-  }
-
-  __weak typeof(self) weakSelf = self;
-  FLTSavePhotoDelegate *savePhotoDelegate = [[FLTSavePhotoDelegate alloc]
-           initWithPath:path
-                ioQueue:self.photoIOQueue
-      completionHandler:^(NSString *_Nullable path, NSError *_Nullable error) {
-        typeof(self) strongSelf = weakSelf;
-        if (!strongSelf) return;
-        dispatch_async(strongSelf.captureSessionQueue, ^{
-          // cannot use the outter `strongSelf`
-          typeof(self) strongSelf = weakSelf;
-          if (!strongSelf) return;
-          [strongSelf.inProgressSavePhotoDelegates removeObjectForKey:@(settings.uniqueID)];
-        });
-
-        if (error) {
-          completion(nil, FlutterErrorFromNSError(error));
-        } else {
-          NSAssert(path, @"Path must not be nil if no error.");
-          completion(path, nil);
-        }
-      }];
-
-  NSAssert(dispatch_get_specific(FLTCaptureSessionQueueSpecific),
-           @"save photo delegate references must be updated on the capture session queue");
-  self.inProgressSavePhotoDelegates[@(settings.uniqueID)] = savePhotoDelegate;
-  [self.capturePhotoOutput capturePhotoWithSettings:settings delegate:savePhotoDelegate];
-}
-
 - (AVCaptureVideoOrientation)getVideoOrientationForDeviceOrientation:
     (UIDeviceOrientation)deviceOrientation {
   if (deviceOrientation == UIDeviceOrientationPortrait) {
@@ -288,32 +215,6 @@ - (AVCaptureVideoOrientation)getVideoOrientationForDeviceOrientation:
   }
 }
 
-- (NSString *)getTemporaryFilePathWithExtension:(NSString *)extension
-                                      subfolder:(NSString *)subfolder
-                                         prefix:(NSString *)prefix
-                                          error:(NSError **)error {
-  NSString *docDir =
-      NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];
-  NSString *fileDir =
-      [[docDir stringByAppendingPathComponent:@"camera"] stringByAppendingPathComponent:subfolder];
-  NSString *fileName = [prefix stringByAppendingString:[[NSUUID UUID] UUIDString]];
-  NSString *file =
-      [[fileDir stringByAppendingPathComponent:fileName] stringByAppendingPathExtension:extension];
-
-  NSFileManager *fm = [NSFileManager defaultManager];
-  if (![fm fileExistsAtPath:fileDir]) {
-    BOOL success = [[NSFileManager defaultManager] createDirectoryAtPath:fileDir
-                                             withIntermediateDirectories:true
-                                                              attributes:nil
-                                                                   error:error];
-    if (!success) {
-      return nil;
-    }
-  }
-
-  return file;
-}
-
 - (BOOL)setCaptureSessionPreset:(FCPPlatformResolutionPreset)resolutionPreset
                       withError:(NSError **)error {
   switch (resolutionPreset) {

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

@@ -4,16 +4,10 @@
 
 #import "./include/camera_avfoundation/QueueUtils.h"
 
-const char *FLTCaptureSessionQueueSpecific = "capture_session_queue";
-
 void FLTEnsureToRunOnMainQueue(dispatch_block_t block) {
   if (!NSThread.isMainThread) {
     dispatch_async(dispatch_get_main_queue(), block);
   } else {
     block();
   }
 }
-
-void FLTDispatchQueueSetSpecific(dispatch_queue_t queue, const void *key) {
-  dispatch_queue_set_specific(queue, key, (void *)key, NULL);
-}

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

@@ -70,19 +70,12 @@ NS_ASSUME_NONNULL_BEGIN
 /// @param error report to the caller if any error happened creating the camera.
 - (instancetype)initWithConfiguration:(FLTCamConfiguration *)configuration error:(NSError **)error;
 
-- (void)captureToFileWithCompletion:(void (^)(NSString *_Nullable,
-                                              FlutterError *_Nullable))completion;
-
 - (void)startImageStreamWithMessenger:(NSObject<FlutterBinaryMessenger> *)messenger
                            completion:(nonnull void (^)(FlutterError *_Nullable))completion;
 - (void)setUpCaptureSessionForAudioIfNeeded;
 
 // Methods exposed for the Swift DefaultCamera subclass
 - (void)updateOrientation;
-- (nullable NSString *)getTemporaryFilePathWithExtension:(NSString *)extension
-                                               subfolder:(NSString *)subfolder
-                                                  prefix:(NSString *)prefix
-                                                   error:(NSError **)error;
 
 @end
 

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

@@ -6,23 +6,11 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
-/// Queue-specific context data to be associated with the capture session queue.
-extern const char* FLTCaptureSessionQueueSpecific;
-
 /// Ensures the given block to be run on the main queue.
 /// If caller site is already on the main queue, the block will be run
 /// synchronously. Otherwise, the block will be dispatched asynchronously to the
 /// main queue.
 /// @param block the block to be run on the main queue.
 extern void FLTEnsureToRunOnMainQueue(dispatch_block_t block);
 
-/// Calls `dispatch_queue_set_specific` with a key that is used to identify the
-/// queue. This method is needed for compatibility of Swift implementation with
-/// Objective-C code. In Swift, the API for setting key-value pairs on a queue
-/// is different, so Swift code need to call this method to set the key-value
-/// pair on the queue in a way that's compatible with the existing Objective-C
-/// code.
-extern void FLTDispatchQueueSetSpecific(dispatch_queue_t queue,
-                                        const void* key);
-
 NS_ASSUME_NONNULL_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: 0.9.20+5
+version: 0.9.20+6
 
 environment:
   sdk: ^3.6.0