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hellohuanlinhellohuanlin
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[camera]remove cas operation and use dispatch queue instead
1 parent 02b5b3f commit 4bd27c1

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9 files changed

+133
-48
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9 files changed

+133
-48
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‎packages/camera/camera/CHANGELOG.md‎

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## 0.9.4+15
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* Uses dispatch queue for pixel buffer synchronization on iOS.
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15
## 0.9.4+14
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* Restores compatibility with Flutter 2.5 and 2.8.

‎packages/camera/camera/example/ios/Runner.xcodeproj/project.pbxproj‎

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@@ -28,6 +28,7 @@
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E0C6E2002770F01A00EA6AA3 /* ThreadSafeMethodChannelTests.m in Sources */ = {isa = PBXBuildFile; fileRef = E0C6E1FD2770F01A00EA6AA3 /* ThreadSafeMethodChannelTests.m */; };
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E0C6E2012770F01A00EA6AA3 /* ThreadSafeTextureRegistryTests.m in Sources */ = {isa = PBXBuildFile; fileRef = E0C6E1FE2770F01A00EA6AA3 /* ThreadSafeTextureRegistryTests.m */; };
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E0C6E2022770F01A00EA6AA3 /* ThreadSafeEventChannelTests.m in Sources */ = {isa = PBXBuildFile; fileRef = E0C6E1FF2770F01A00EA6AA3 /* ThreadSafeEventChannelTests.m */; };
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E0CDBAC227CD9729002561D9 /* CameraTestUtils.m in Sources */ = {isa = PBXBuildFile; fileRef = E0CDBAC127CD9729002561D9 /* CameraTestUtils.m */; };
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E0F95E3D27A32AB900699390 /* CameraPropertiesTests.m in Sources */ = {isa = PBXBuildFile; fileRef = E0F95E3C27A32AB900699390 /* CameraPropertiesTests.m */; };
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E487C86026D686A10034AC92 /* CameraPreviewPauseTests.m in Sources */ = {isa = PBXBuildFile; fileRef = E487C85F26D686A10034AC92 /* CameraPreviewPauseTests.m */; };
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F6EE622F2710A6FC00905E4A /* MockFLTThreadSafeFlutterResult.m in Sources */ = {isa = PBXBuildFile; fileRef = F6EE622E2710A6FC00905E4A /* MockFLTThreadSafeFlutterResult.m */; };
@@ -91,6 +92,8 @@
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E0C6E1FD2770F01A00EA6AA3 /* ThreadSafeMethodChannelTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ThreadSafeMethodChannelTests.m; sourceTree = "<group>"; };
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E0C6E1FE2770F01A00EA6AA3 /* ThreadSafeTextureRegistryTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ThreadSafeTextureRegistryTests.m; sourceTree = "<group>"; };
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E0C6E1FF2770F01A00EA6AA3 /* ThreadSafeEventChannelTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ThreadSafeEventChannelTests.m; sourceTree = "<group>"; };
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E0CDBAC027CD9729002561D9 /* CameraTestUtils.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = CameraTestUtils.h; sourceTree = "<group>"; };
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E0CDBAC127CD9729002561D9 /* CameraTestUtils.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = CameraTestUtils.m; sourceTree = "<group>"; };
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E0F95E3C27A32AB900699390 /* CameraPropertiesTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = CameraPropertiesTests.m; sourceTree = "<group>"; };
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E487C85F26D686A10034AC92 /* CameraPreviewPauseTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = CameraPreviewPauseTests.m; sourceTree = "<group>"; };
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F63F9EED27143B19002479BF /* MockFLTThreadSafeFlutterResult.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = MockFLTThreadSafeFlutterResult.h; sourceTree = "<group>"; };
@@ -131,6 +134,8 @@
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E04F108527A87CA600573D0C /* FLTSavePhotoDelegateTests.m */,
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E071CF7127B3061B006EF3BA /* FLTCamPhotoCaptureTests.m */,
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E071CF7327B31DE4006EF3BA /* FLTCamSampleBufferTests.m */,
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E0CDBAC027CD9729002561D9 /* CameraTestUtils.h */,
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E0CDBAC127CD9729002561D9 /* CameraTestUtils.m */,
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E01EE4A72799F3A5008C1950 /* QueueHelperTests.m */,
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E487C85F26D686A10034AC92 /* CameraPreviewPauseTests.m */,
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F6EE622E2710A6FC00905E4A /* MockFLTThreadSafeFlutterResult.m */,
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E071CF7427B31DE4006EF3BA /* FLTCamSampleBufferTests.m in Sources */,
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E04F108627A87CA600573D0C /* FLTSavePhotoDelegateTests.m in Sources */,
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F6EE622F2710A6FC00905E4A /* MockFLTThreadSafeFlutterResult.m in Sources */,
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E0CDBAC227CD9729002561D9 /* CameraTestUtils.m in Sources */,
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334733EA2668111C00DCC49E /* CameraOrientationTests.m in Sources */,
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E032F250279F5E94009E9028 /* CameraCaptureSessionQueueRaceConditionTests.m in Sources */,
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E0C6E2022770F01A00EA6AA3 /* ThreadSafeEventChannelTests.m in Sources */,

‎packages/camera/camera/example/ios/RunnerTests/CameraTestUtils.h‎

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// Copyright 2013 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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@import camera;
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NS_ASSUME_NONNULL_BEGIN
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@interface CameraTestUtils : NSObject
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/// Creates an `FLTCam` that runs its capture session operations on a given queue.
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/// @param captureSessionQueue the capture session queue
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/// @return an FLTCam object.
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+ (FLTCam *)createFLTCamWithCaptureSessionQueue:(dispatch_queue_t)captureSessionQueue;
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/// Creates a test sample buffer.
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/// @return a test sample buffer.
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+ (CMSampleBufferRef)createTestSampleBuffer;
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@end
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NS_ASSUME_NONNULL_END

‎packages/camera/camera/example/ios/RunnerTests/CameraTestUtils.m‎

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// Copyright 2013 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#import "CameraTestUtils.h"
6+
#import <OCMock/OCMock.h>
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@import AVFoundation;
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9+
@implementation CameraTestUtils
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11+
+ (FLTCam *)createFLTCamWithCaptureSessionQueue:(dispatch_queue_t)captureSessionQueue {
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id inputMock = OCMClassMock([AVCaptureDeviceInput class]);
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OCMStub([inputMock deviceInputWithDevice:[OCMArg any] error:[OCMArg setTo:nil]])
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.andReturn(inputMock);
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id sessionMock = OCMClassMock([AVCaptureSession class]);
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OCMStub([sessionMock alloc]).andReturn(sessionMock);
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OCMStub([sessionMock addInputWithNoConnections:[OCMArg any]]); // no-op
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OCMStub([sessionMock canSetSessionPreset:[OCMArg any]]).andReturn(YES);
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return [[FLTCam alloc] initWithCameraName:@"camera"
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resolutionPreset:@"medium"
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enableAudio:true
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orientation:UIDeviceOrientationPortrait
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captureSessionQueue:captureSessionQueue
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error:nil];
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}
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+ (CMSampleBufferRef)createTestSampleBuffer {
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CVPixelBufferRef pixelBuffer;
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CVPixelBufferCreate(kCFAllocatorDefault, 100, 100, kCVPixelFormatType_32BGRA, NULL, &pixelBuffer);
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CMFormatDescriptionRef formatDescription;
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CMVideoFormatDescriptionCreateForImageBuffer(kCFAllocatorDefault, pixelBuffer,
35+
&formatDescription);
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CMSampleTimingInfo timingInfo = {CMTimeMake(1, 44100), kCMTimeZero, kCMTimeInvalid};
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CMSampleBufferRef sampleBuffer;
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CMSampleBufferCreateReadyWithImageBuffer(kCFAllocatorDefault, pixelBuffer, formatDescription,
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&timingInfo, &sampleBuffer);
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CFRelease(pixelBuffer);
44+
CFRelease(formatDescription);
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return sampleBuffer;
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}
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@end

‎packages/camera/camera/example/ios/RunnerTests/FLTCamPhotoCaptureTests.m‎

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@import AVFoundation;
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@import XCTest;
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#import <OCMock/OCMock.h>
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#import "CameraTestUtils.h"
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/// Includes test cases related to photo capture operations for FLTCam class.
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@interface FLTCamPhotoCaptureTests : XCTestCase
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@end
@@ -22,7 +24,7 @@ - (void)testCaptureToFile_mustReportErrorToResultIfSavePhotoDelegateCompletionsW
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dispatch_queue_t captureSessionQueue = dispatch_queue_create("capture_session_queue", NULL);
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dispatch_queue_set_specific(captureSessionQueue, FLTCaptureSessionQueueSpecific,
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(void *)FLTCaptureSessionQueueSpecific, NULL);
25-
FLTCam *cam = [self createFLTCamWithCaptureSessionQueue:captureSessionQueue];
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FLTCam *cam = [CameraTestUtils createFLTCamWithCaptureSessionQueue:captureSessionQueue];
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AVCapturePhotoSettings *settings = [AVCapturePhotoSettings photoSettings];
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id mockSettings = OCMClassMock([AVCapturePhotoSettings class]);
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OCMStub([mockSettings photoSettings]).andReturn(settings);
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dispatch_queue_t captureSessionQueue = dispatch_queue_create("capture_session_queue", NULL);
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dispatch_queue_set_specific(captureSessionQueue, FLTCaptureSessionQueueSpecific,
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(void *)FLTCaptureSessionQueueSpecific, NULL);
64-
FLTCam *cam = [self createFLTCamWithCaptureSessionQueue:captureSessionQueue];
66+
FLTCam *cam = [CameraTestUtils createFLTCamWithCaptureSessionQueue:captureSessionQueue];
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AVCapturePhotoSettings *settings = [AVCapturePhotoSettings photoSettings];
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id mockSettings = OCMClassMock([AVCapturePhotoSettings class]);
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[self waitForExpectationsWithTimeout:1 handler:nil];
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}
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95-
/// Creates an `FLTCam` that runs its operations on a given capture session queue.
96-
- (FLTCam *)createFLTCamWithCaptureSessionQueue:(dispatch_queue_t)captureSessionQueue {
97-
id inputMock = OCMClassMock([AVCaptureDeviceInput class]);
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OCMStub([inputMock deviceInputWithDevice:[OCMArg any] error:[OCMArg setTo:nil]])
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.andReturn(inputMock);
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id sessionMock = OCMClassMock([AVCaptureSession class]);
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OCMStub([sessionMock alloc]).andReturn(sessionMock);
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OCMStub([sessionMock addInputWithNoConnections:[OCMArg any]]); // no-op
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OCMStub([sessionMock canSetSessionPreset:[OCMArg any]]).andReturn(YES);
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return [[FLTCam alloc] initWithCameraName:@"camera"
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resolutionPreset:@"medium"
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enableAudio:true
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orientation:UIDeviceOrientationPortrait
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captureSessionQueue:captureSessionQueue
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error:nil];
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}
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@end

‎packages/camera/camera/example/ios/RunnerTests/FLTCamSampleBufferTests.m‎

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@import AVFoundation;
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@import XCTest;
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#import <OCMock/OCMock.h>
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#import "CameraTestUtils.h"
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/// Includes test cases related to sample buffer handling for FLTCam class.
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@interface FLTCamSampleBufferTests : XCTestCase
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@end
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@implementation FLTCamSampleBufferTests
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1719
- (void)testSampleBufferCallbackQueueMustBeCaptureSessionQueue {
18-
id inputMock = OCMClassMock([AVCaptureDeviceInput class]);
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OCMStub([inputMock deviceInputWithDevice:[OCMArg any] error:[OCMArg setTo:nil]])
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.andReturn(inputMock);
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id sessionMock = OCMClassMock([AVCaptureSession class]);
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OCMStub([sessionMock alloc]).andReturn(sessionMock);
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OCMStub([sessionMock addInputWithNoConnections:[OCMArg any]]); // no-op
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OCMStub([sessionMock canSetSessionPreset:[OCMArg any]]).andReturn(YES);
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dispatch_queue_t captureSessionQueue = dispatch_queue_create("testing", NULL);
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FLTCam *cam = [[FLTCam alloc] initWithCameraName:@"camera"
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resolutionPreset:@"medium"
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enableAudio:true
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orientation:UIDeviceOrientationPortrait
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captureSessionQueue:captureSessionQueue
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error:nil];
34-
XCTAssertEqual(captureSessionQueue, cam.captureVideoOutput.sampleBufferCallbackQueue);
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FLTCam *cam = [CameraTestUtils createFLTCamWithCaptureSessionQueue:captureSessionQueue];
22+
XCTAssertEqual(captureSessionQueue, cam.captureVideoOutput.sampleBufferCallbackQueue,
23+
@"Sample buffer callback queue must be the capture session queue.");
24+
}
25+
26+
- (void)testCopyPixelBuffer {
27+
FLTCam *cam =
28+
[CameraTestUtils createFLTCamWithCaptureSessionQueue:dispatch_queue_create("test", NULL)];
29+
CMSampleBufferRef capturedSampleBuffer = [CameraTestUtils createTestSampleBuffer];
30+
CVPixelBufferRef capturedPixelBuffer = CMSampleBufferGetImageBuffer(capturedSampleBuffer);
31+
// Mimic sample buffer callback when captured a new video sample
32+
[cam captureOutput:cam.captureVideoOutput
33+
didOutputSampleBuffer:capturedSampleBuffer
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fromConnection:OCMClassMock([AVCaptureConnection class])];
35+
CVPixelBufferRef deliveriedPixelBuffer = [cam copyPixelBuffer];
36+
XCTAssertEqual(deliveriedPixelBuffer, capturedPixelBuffer,
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@"FLTCam must deliver the latest captured pixel buffer to copyPixelBuffer API.");
38+
CFRelease(capturedSampleBuffer);
3539
}
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3741
@end

‎packages/camera/camera/ios/Classes/FLTCam.m‎

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@@ -52,7 +52,9 @@ @interface FLTCam () <AVCaptureVideoDataOutputSampleBufferDelegate,
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@property(readonly, nonatomic) AVCaptureSession *captureSession;
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@property(readonly, nonatomic) AVCaptureInput *captureVideoInput;
55-
@property(readonly) CVPixelBufferRef volatile latestPixelBuffer;
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/// Tracks the latest pixel buffer sent from AVFoundation's sample buffer delegate callback.
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/// Used to deliver the latest pixel buffer to the flutter engine via the `copyPixelBuffer` API.
57+
@property(readwrite, nonatomic) CVPixelBufferRef latestPixelBuffer;
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@property(readonly, nonatomic) CGSize captureSize;
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@property(strong, nonatomic) AVAssetWriter *videoWriter;
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@property(strong, nonatomic) AVAssetWriterInput *videoWriterInput;
@@ -76,6 +78,8 @@ @interface FLTCam () <AVCaptureVideoDataOutputSampleBufferDelegate,
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@property AVAssetWriterInputPixelBufferAdaptor *videoAdaptor;
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/// All FLTCam's state access and capture session related operations should be on run on this queue.
7880
@property(strong, nonatomic) dispatch_queue_t captureSessionQueue;
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/// The queue on which `latestPixelBuffer` property is accessed.
82+
@property(strong, nonatomic) dispatch_queue_t pixelBufferSynchronizationQueue;
7983
/// The queue on which captured photos (not videos) are written to disk.
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/// Videos are written to disk by `videoAdaptor` on an internal queue managed by AVFoundation.
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@property(strong, nonatomic) dispatch_queue_t photoIOQueue;
@@ -101,6 +105,8 @@ - (instancetype)initWithCameraName:(NSString *)cameraName
101105
}
102106
_enableAudio = enableAudio;
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_captureSessionQueue = captureSessionQueue;
108+
_pixelBufferSynchronizationQueue =
109+
dispatch_queue_create("io.flutter.camera.pixelBufferSynchronizationQueue", NULL);
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_photoIOQueue = dispatch_queue_create("io.flutter.camera.photoIOQueue", NULL);
105111
_captureSession = [[AVCaptureSession alloc] init];
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_captureDevice = [AVCaptureDevice deviceWithUniqueID:cameraName];
@@ -355,10 +361,15 @@ - (void)captureOutput:(AVCaptureOutput *)output
355361
if (output == _captureVideoOutput) {
356362
CVPixelBufferRef newBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
357363
CFRetain(newBuffer);
358-
CVPixelBufferRef old = _latestPixelBuffer;
359-
while (!OSAtomicCompareAndSwapPtrBarrier(old, newBuffer, (void **)&_latestPixelBuffer)) {
360-
old = _latestPixelBuffer;
361-
}
364+
365+
__block CVPixelBufferRef old = nil;
366+
// Use `dispatch_sync` to avoid unnecessary context switch under common non-contest scenarios,
367+
// i.e. 2 queues sharing the same thread. Under rare contest scenarios, it will not block for
368+
// too long since the critical section is quite lightweight.
369+
dispatch_sync(self.pixelBufferSynchronizationQueue, ^{
370+
old = self.latestPixelBuffer;
371+
self.latestPixelBuffer = newBuffer;
372+
});
362373
if (old != nil) {
363374
CFRelease(old);
364375
}
@@ -575,11 +586,12 @@ - (void)dealloc {
575586
}
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577588
- (CVPixelBufferRef)copyPixelBuffer {
578-
CVPixelBufferRef pixelBuffer = _latestPixelBuffer;
579-
while (!OSAtomicCompareAndSwapPtrBarrier(pixelBuffer, nil, (void **)&_latestPixelBuffer)) {
580-
pixelBuffer = _latestPixelBuffer;
581-
}
582-
589+
__block CVPixelBufferRef pixelBuffer = nil;
590+
// `copyPixelBuffer` API requires synchronous return, so we have to use `dispatch_sync`.
591+
dispatch_sync(self.pixelBufferSynchronizationQueue, ^{
592+
pixelBuffer = self.latestPixelBuffer;
593+
self.latestPixelBuffer = nil;
594+
});
583595
return pixelBuffer;
584596
}
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‎packages/camera/camera/ios/Classes/FLTCam_Test.h‎

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@property(readonly, nonatomic)
2323
NSMutableDictionary<NSNumber *, FLTSavePhotoDelegate *> *inProgressSavePhotoDelegates;
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25+
/// Delegate callback when receive a new video or audio sample.
26+
/// Exposed for unit tests.
27+
- (void)captureOutput:(AVCaptureOutput *)output
28+
didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer
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fromConnection:(AVCaptureConnection *)connection;
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@end

‎packages/camera/camera/pubspec.yaml‎

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@@ -4,7 +4,7 @@ description: A Flutter plugin for controlling the camera. Supports previewing
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Dart.
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repository: https://github.com/flutter/plugins/tree/main/packages/camera/camera
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issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+camera%22
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version: 0.9.4+14
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version: 0.9.4+15
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environment:
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sdk: ">=2.14.0 <3.0.0"

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