create queue helper

Author: hellohuanlin

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

@@ -19,8 +19,9 @@ - (void)testCaptureToFile_mustReportErrorToResultIfSavePhotoDelegateCompletionsW
       [self expectationWithDescription:
                 @"Must send error to result if save photo delegate completes with error."];
 
-  dispatch_queue_t captureSessionQueue = dispatch_queue_create("capture_session_queue", NULL);
-  [QueueHelper setSpecific:FLTCaptureSessionQueueSpecific forQueue:captureSessionQueue];
+  dispatch_queue_t captureSessionQueue =
+      [QueueHelper createQueueWithLabel:"capture_session_queue"
+                               specific:FLTCaptureSessionQueueSpecific];
   FLTCam *cam = [self createFLTCamWithCaptureSessionQueue:captureSessionQueue];
   AVCapturePhotoSettings *settings = [AVCapturePhotoSettings photoSettings];
   id mockSettings = OCMClassMock([AVCapturePhotoSettings class]);
@@ -57,8 +58,9 @@ - (void)testCaptureToFile_mustReportPathToResultIfSavePhotoDelegateCompletionsWi
       [self expectationWithDescription:
                 @"Must send file path to result if save photo delegate completes with file path."];
 
-  dispatch_queue_t captureSessionQueue = dispatch_queue_create("capture_session_queue", NULL);
-  [QueueHelper setSpecific:FLTCaptureSessionQueueSpecific forQueue:captureSessionQueue];
+  dispatch_queue_t captureSessionQueue =
+      [QueueHelper createQueueWithLabel:"capture_session_queue"
+                               specific:FLTCaptureSessionQueueSpecific];
   FLTCam *cam = [self createFLTCamWithCaptureSessionQueue:captureSessionQueue];
 
   AVCapturePhotoSettings *settings = [AVCapturePhotoSettings photoSettings];

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

@@ -35,11 +35,18 @@ - (void)testShouldDispatchToMainQueueIfCalledFromBackgroundQueue {
   [self waitForExpectationsWithTimeout:1 handler:nil];
 }
 
-- (void)testSetAndCheckQueueSpecific {
-  dispatch_queue_t queue = dispatch_queue_create("test", NULL);
+- (void)testCreateQueue {
+  const char *label = "label";
   const char *specific = "specific";
-  [QueueHelper setSpecific:specific forQueue:queue];
+  dispatch_queue_t queue = [QueueHelper createQueueWithLabel:label specific:specific];
+  XCTAssert(0 == strcmp(label, dispatch_queue_get_label(queue)), "Must set the correct label.");
+  XCTAssert(0 == strcmp(specific, dispatch_queue_get_specific(queue, specific)),
+            "Must set the correct specific.");
+}
 
+- (void)testIsCurrentlyOnQueueWithSpecific {
+  const char *specific = "specific";
+  dispatch_queue_t queue = [QueueHelper createQueueWithLabel:"test" specific:specific];
   XCTAssertFalse([QueueHelper isCurrentlyOnQueueWithSpecific:specific],
                  @"Must not be on the test queue before dispatching to it.");
 

packages/camera/camera/ios/Classes/CameraPlugin.m

@@ -38,8 +38,8 @@ - (instancetype)initWithRegistry:(NSObject<FlutterTextureRegistry> *)registry
   NSAssert(self, @"super init cannot be nil");
   _registry = [[FLTThreadSafeTextureRegistry alloc] initWithTextureRegistry:registry];
   _messenger = messenger;
-  _captureSessionQueue = dispatch_queue_create("io.flutter.camera.captureSessionQueue", NULL);
-  [QueueHelper setSpecific:FLTCaptureSessionQueueSpecific forQueue:_captureSessionQueue];
+  _captureSessionQueue = [QueueHelper createQueueWithLabel:"io.flutter.camera.captureSessionQueue"
+                                                  specific:FLTCaptureSessionQueueSpecific];
 
   [self initDeviceEventMethodChannel];
   [self startOrientationListener];

packages/camera/camera/ios/Classes/QueueHelper.h

@@ -14,17 +14,19 @@ extern const char *FLTCaptureSessionQueueSpecific;
 
 /// Ensure 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 dispatch asynchronously to the main queue.
+/// block will be dispatched asynchronously to the main queue.
 /// @param block the block to be run on the main queue.
 + (void)ensureToRunOnMainQueue:(void (^)(void))block;
 
-/// Sets the queue-specific context data for a given queue.
-/// @param specific the queue-specific context data.
-/// @param queue the queue to be associated with the context data.
-+ (void)setSpecific:(const char *)specific forQueue:(dispatch_queue_t)queue;
+/// Creates a dispatch queue with a label and queue-specific context data.
+/// @param label label for debugging purpose.
+/// @param specific queue-specific context data.
+/// @return the created dispatch queue with the given label and queue-specific context data.
++ (dispatch_queue_t)createQueueWithLabel:(const char *)label specific:(const char *)specific;
 
 /// Check if the caller is on a certain queue specified by its queue-specifc context data.
-/// @returns YES if the caller is on a certain queue specified by its queue-specific context data.
+/// @param specific queue-specific context data.
+/// @return YES if the caller is on a certain queue specified by its queue-specific context data;
 /// NO otherwise.
 + (BOOL)isCurrentlyOnQueueWithSpecific:(const char *)specific;
 

packages/camera/camera/ios/Classes/QueueHelper.m

@@ -16,8 +16,10 @@ + (void)ensureToRunOnMainQueue:(void (^)(void))block {
   }
 }
 
-+ (void)setSpecific:(const char *)specific forQueue:(dispatch_queue_t)queue {
++ (dispatch_queue_t)createQueueWithLabel:(const char *)label specific:(const char *)specific {
+  dispatch_queue_t queue = dispatch_queue_create(label, NULL);
   dispatch_queue_set_specific(queue, specific, (void *)specific, NULL);
+  return queue;
 }
 
 + (BOOL)isCurrentlyOnQueueWithSpecific:(const char *)specific {