From d5feb3a4898779be4d596217910c1fc6d861ec92 Mon Sep 17 00:00:00 2001
From: Ben Hagen <ben@ottomatic.io>
Date: Fri, 12 Nov 2021 19:12:19 +0100
Subject: [PATCH] Use synchronized

---
 .../macos/Classes/FLTVideoPlayerPlugin.m      | 69 +++++++++++--------
 1 file changed, 40 insertions(+), 29 deletions(-)

diff --git a/packages/video_player/video_player_macos/macos/Classes/FLTVideoPlayerPlugin.m b/packages/video_player/video_player_macos/macos/Classes/FLTVideoPlayerPlugin.m
index f223340aaf2b..151e97f9e4b0 100644
--- a/packages/video_player/video_player_macos/macos/Classes/FLTVideoPlayerPlugin.m
+++ b/packages/video_player/video_player_macos/macos/Classes/FLTVideoPlayerPlugin.m
@@ -172,8 +172,10 @@ - (void)notifyIfFrameAvailable {
   } else {
     CVPixelBufferRef pixelBuffer = [_videoOutput copyPixelBufferForItemTime:outputItemTime itemTimeForDisplay:NULL];
     if (pixelBuffer != NULL) {
-      CVBufferRelease(_lastValidFrame);
-      _lastValidFrame = pixelBuffer;
+      @synchronized (self) {
+        CVBufferRelease(_lastValidFrame);
+        _lastValidFrame = pixelBuffer;
+      }
     }
     [_frameUpdater notifyFrameAvailable];
   }
@@ -185,9 +187,7 @@ static CVReturn OnDisplayLink(CVDisplayLinkRef CV_NONNULL displayLink,
                               CVOptionFlags* CV_NONNULL flagsOut,
                               void* CV_NULLABLE displayLinkContext) {
   __weak FLTVideoPlayer* video_player = (__bridge FLTVideoPlayer*)(displayLinkContext);
-  dispatch_async(dispatch_get_main_queue(), ^{
-    [video_player notifyIfFrameAvailable];
-  });
+  [video_player notifyIfFrameAvailable];
   return kCVReturnSuccess;
 }
 
@@ -403,9 +403,7 @@ - (void)seekTo:(int)location {
   [_player seekToTime:CMTimeMake(location, 1000)
       toleranceBefore:kCMTimeZero
        toleranceAfter:kCMTimeZero];
-  dispatch_async(dispatch_get_main_queue(), ^{
-    [self notifyIfFrameAvailable];
-  });
+  [self notifyIfFrameAvailable];
 }
 
 - (void)setIsLooping:(bool)isLooping {
@@ -445,28 +443,41 @@ - (CVPixelBufferRef)copyPixelBuffer {
   //
   // Unlike on iOS, the macOS embedder does show the last frame when
   // we return NULL from `copyPixelBuffer`.
-  CVPixelBufferLockBaseAddress(_lastValidFrame, kCVPixelBufferLock_ReadOnly);
-  int bufferWidth = (int)CVPixelBufferGetWidth(_lastValidFrame);
-  int bufferHeight = (int)CVPixelBufferGetHeight(_lastValidFrame);
-  size_t bytesPerRow = CVPixelBufferGetBytesPerRow(_lastValidFrame);
-  uint8_t *baseAddress = CVPixelBufferGetBaseAddress(_lastValidFrame);
-  NSDictionary* pixBuffAttributes = @{
-    (id)kCVPixelBufferPixelFormatTypeKey : @(kCVPixelFormatType_32BGRA),
-    (id)kCVPixelBufferIOSurfacePropertiesKey : @{},
-    (id)kCVPixelBufferOpenGLCompatibilityKey : @YES,
-    (id)kCVPixelBufferMetalCompatibilityKey : @YES,
-  };
-
-  CVPixelBufferRef pixelBufferCopy = NULL;
-  CVPixelBufferCreate(kCFAllocatorDefault, bufferWidth, bufferHeight,kCVPixelFormatType_32BGRA,
-                      CFBridgingRetain(pixBuffAttributes), &pixelBufferCopy);
-  CVPixelBufferLockBaseAddress(pixelBufferCopy, 0);
-  uint8_t *copyBaseAddress = CVPixelBufferGetBaseAddress(pixelBufferCopy);
-  memcpy(copyBaseAddress, baseAddress, bufferHeight * bytesPerRow);
 
-  CVPixelBufferUnlockBaseAddress(_lastValidFrame, kCVPixelBufferLock_ReadOnly);
-  CVPixelBufferUnlockBaseAddress(pixelBufferCopy, 0);
-  return pixelBufferCopy;
+  if (_lastValidFrame == NULL) {
+    return NULL;
+  }
+  
+  @synchronized (self) {
+    CVPixelBufferLockBaseAddress(_lastValidFrame, kCVPixelBufferLock_ReadOnly);
+    int bufferWidth = (int)CVPixelBufferGetWidth(_lastValidFrame);
+    int bufferHeight = (int)CVPixelBufferGetHeight(_lastValidFrame);
+    size_t bytesPerRow = CVPixelBufferGetBytesPerRow(_lastValidFrame);
+    uint8_t *baseAddress = CVPixelBufferGetBaseAddress(_lastValidFrame);
+    
+    if (baseAddress == NULL) {
+      NSLog(@"----> baseadress is NULL");
+      return NULL;
+    }
+    
+    NSDictionary* pixBuffAttributes = @{
+      (id)kCVPixelBufferPixelFormatTypeKey : @(kCVPixelFormatType_32BGRA),
+      (id)kCVPixelBufferIOSurfacePropertiesKey : @{},
+      (id)kCVPixelBufferOpenGLCompatibilityKey : @YES,
+      (id)kCVPixelBufferMetalCompatibilityKey : @YES,
+    };
+
+    CVPixelBufferRef pixelBufferCopy = NULL;
+    CVPixelBufferCreate(kCFAllocatorDefault, bufferWidth, bufferHeight,kCVPixelFormatType_32BGRA,
+                        CFBridgingRetain(pixBuffAttributes), &pixelBufferCopy);
+    CVPixelBufferLockBaseAddress(pixelBufferCopy, 0);
+    uint8_t *copyBaseAddress = CVPixelBufferGetBaseAddress(pixelBufferCopy);
+    memcpy(copyBaseAddress, baseAddress, bufferHeight * bytesPerRow);
+
+    CVPixelBufferUnlockBaseAddress(_lastValidFrame, kCVPixelBufferLock_ReadOnly);
+    CVPixelBufferUnlockBaseAddress(pixelBufferCopy, 0);
+    return pixelBufferCopy;
+  }
 }
 
 - (void)onTextureUnregistered:(NSObject<FlutterTexture>*)texture {