Remove ASImageNode thread affinity asserts (#57).

AsyncDisplayKit/ASDisplayNode.mm

@@ -63,6 +63,17 @@ CGFloat ASDisplayNodeScreenScale()
   return screenScale;
 }
 
+void ASDisplayNodePerformBlockOnMainThread(void (^block)())
+{
+  if ([NSThread isMainThread]) {
+    block();
+  } else {
+    dispatch_async(dispatch_get_main_queue(), ^{
+      block();
+    });
+  }
+}
+
 + (void)initialize
 {
   if (self == [ASDisplayNode class]) {

AsyncDisplayKit/ASImageNode.mm

@@ -106,35 +106,35 @@
 
 - (void)setImage:(UIImage *)image
 {
-  ASDisplayNodeAssertThreadAffinity(self);
   ASDN::MutexLocker l(_imageLock);
   if (_image != image) {
     _image = image;
+    ASDisplayNodePerformBlockOnMainThread(^{
       [self invalidateCalculatedSize];
       [self setNeedsDisplay];
+    });
   }
 }
 
 - (UIImage *)image
 {
-  ASDisplayNodeAssertThreadAffinity(self);
   ASDN::MutexLocker l(_imageLock);
   return _image;
 }
 
 - (void)setTint:(ASImageNodeTint)tint
 {
-  ASDisplayNodeAssertThreadAffinity(self);
   ASDN::MutexLocker l(_imageLock);
   if (_tint != tint) {
     _tint = tint;
+    ASDisplayNodePerformBlockOnMainThread(^{
       [self setNeedsDisplay];
+    });
   }
 }
 
 - (ASImageNodeTint)tint
 {
-  ASDisplayNodeAssertThreadAffinity(self);
   ASDN::MutexLocker l(_imageLock);
   return _tint;
 }
@@ -281,19 +281,16 @@
 #pragma mark - Cropping
 - (BOOL)isCropEnabled
 {
-  ASDisplayNodeAssertThreadAffinity(self);
   return _cropEnabled;
 }
 
 - (void)setCropEnabled:(BOOL)cropEnabled
 {
-  ASDisplayNodeAssertThreadAffinity(self);
   [self setCropEnabled:cropEnabled recropImmediately:NO inBounds:self.bounds];
 }
 
 - (void)setCropEnabled:(BOOL)cropEnabled recropImmediately:(BOOL)recropImmediately inBounds:(CGRect)cropBounds
 {
-  ASDisplayNodeAssertThreadAffinity(self);
   if (_cropEnabled == cropEnabled)
     return;
 
@@ -303,23 +300,22 @@
   // If we have an image to display, display it, respecting our recrop flag.
   if (self.image)
   {
+    ASDisplayNodePerformBlockOnMainThread(^{
       if (recropImmediately)
         [self displayImmediately];
       else
         [self setNeedsDisplay];
+    });
   }
 }
 
 - (CGRect)cropRect
 {
-  ASDisplayNodeAssertThreadAffinity(self);
   return _cropRect;
 }
 
 - (void)setCropRect:(CGRect)cropRect
 {
-  ASDisplayNodeAssertThreadAffinity(self);
-
   if (CGRectEqualToRect(_cropRect, cropRect))
     return;
 
@@ -332,8 +328,10 @@
   BOOL isCroppingImage = ((boundsSize.width < imageSize.width) || (boundsSize.height < imageSize.height));
 
   // Re-display if we need to.
+  ASDisplayNodePerformBlockOnMainThread(^{
     if (self.nodeLoaded && self.contentMode == UIViewContentModeScaleAspectFill && isCroppingImage)
       [self setNeedsDisplay];
+  });
 }
 
 @end

AsyncDisplayKit/Private/ASDisplayNodeInternal.h

@@ -20,6 +20,7 @@
 
 BOOL ASDisplayNodeSubclassOverridesSelector(Class subclass, SEL selector);
 CGFloat ASDisplayNodeScreenScale();
+void ASDisplayNodePerformBlockOnMainThread(void (^block)());
 
 @class _ASPendingState;
 

examples/Kittens/Sample/KittenNode.m

@@ -138,15 +138,7 @@ static const CGFloat kInnerPadding = 10.0f;
                              return;
 
                            // set our image node's data
-                           if (_imageNode.nodeLoaded) {
-                             dispatch_sync(dispatch_get_main_queue(), ^{
-                               // once the node's view is loaded, the node should only be used on the main thread
                            _imageNode.image = [UIImage imageWithData:data];
-                             });
-                           } else {
-                             // if the node hasn't loaded, we can use it on a background thread
-                             _imageNode.image = [UIImage imageWithData:data];
-                           }
                          }];
 }