Merge pull request #1304 from garrettmoon/betterSkipClearContents

[ASDisplayNode] Coalesce -clearContents onto the next runloop, so it can be skipped if re-added to hierarchy in move operation.

AsyncDisplayKit/ASDisplayNode.mm

@@ -1227,7 +1227,7 @@ static bool disableNotificationsForMovingBetweenParents(ASDisplayNode *from, ASD
   if (isMovingEquivalentParents) {
     [subnode __incrementVisibilityNotificationsDisabled];
   }
-  [subnode removeFromSupernodeMovingBetweenNodes:YES];
+  [subnode removeFromSupernode];
 
   if (!_subnodes)
     _subnodes = [[NSMutableArray alloc] init];
@@ -1497,11 +1497,6 @@ static NSInteger incrementIfFound(NSInteger i) {
 }
 
 - (void)removeFromSupernode
-{
-  [self removeFromSupernodeMovingBetweenNodes:NO];
-}
-
-- (void)removeFromSupernodeMovingBetweenNodes:(BOOL)movingBetweenNodes
 {
   ASDisplayNodeAssertThreadAffinity(self);
   BOOL shouldRemoveFromSuperviewOrSuperlayer = NO;
@@ -1510,7 +1505,7 @@ static NSInteger incrementIfFound(NSInteger i) {
     ASDN::MutexLocker l(_propertyLock);
     if (!_supernode)
       return;
-    
+
     // Check to ensure that our view or layer is actually inside of our supernode; otherwise, don't remove it.
     // Though _ASDisplayView decouples the supernode if it is inserted inside another view hierarchy, this is
     // more difficult to guarantee with _ASDisplayLayer because CoreAnimation doesn't have a -didMoveToSuperlayer.
@@ -1527,22 +1522,15 @@ static NSInteger incrementIfFound(NSInteger i) {
   // Do this before removing the view from the hierarchy, as the node will clear its supernode pointer when its view is removed from the hierarchy.
   // This call may result in the object being destroyed.
   [_supernode _removeSubnode:self];
-  
+
   if (shouldRemoveFromSuperviewOrSuperlayer) {
     ASPerformBlockOnMainThread(^{
       ASDN::MutexLocker l(_propertyLock);
-      
-      if (movingBetweenNodes) {
-        _flags.isMovingBetweenNodes = YES;
-      }
       if (_flags.layerBacked) {
         [_layer removeFromSuperlayer];
       } else {
         [_view removeFromSuperview];
       }
-      if (movingBetweenNodes) {
-        _flags.isMovingBetweenNodes = NO;
-      }
     });
   }
 }
@@ -1982,14 +1970,6 @@ void recursivelyTriggerDisplayForLayer(CALayer *layer, BOOL shouldBlock)
 - (void)clearContents
 {
   // No-op if these haven't been created yet, as that guarantees they don't have contents that needs to be released.
-  {
-    ASDN::MutexLocker l(_propertyLock);
-    //Do not clear contents if we're mearly moving between nodes
-    if (_flags.isMovingBetweenNodes) {
-      return;
-    }
-  }
-  
   _layer.contents = nil;
   _placeholderLayer.contents = nil;
   _placeholderImage = nil;
@@ -2103,7 +2083,13 @@ void recursivelyTriggerDisplayForLayer(CALayer *layer, BOOL shouldBlock)
         [self setDisplaySuspended:NO];
       } else {
         [self setDisplaySuspended:YES];
-        [self clearContents];
+        //schedule clear contents on next runloop
+        dispatch_async(dispatch_get_main_queue(), ^{
+          ASDN::MutexLocker l(_propertyLock);
+          if (ASInterfaceStateIncludesDisplay(_interfaceState) == NO) {
+            [self clearContents];
+          }
+        });
       }
     } else {
       // NOTE: This case isn't currently supported as setInterfaceState: isn't exposed externally, and all
@@ -2115,7 +2101,13 @@ void recursivelyTriggerDisplayForLayer(CALayer *layer, BOOL shouldBlock)
             [ASDisplayNode scheduleNodeForRecursiveDisplay:self];
           } else {
             [[self asyncLayer] cancelAsyncDisplay];
-            [self clearContents];
+            //schedule clear contents on next runloop
+            dispatch_async(dispatch_get_main_queue(), ^{
+              ASDN::MutexLocker l(_propertyLock);
+              if (ASInterfaceStateIncludesDisplay(_interfaceState) == NO) {
+                [self clearContents];
+              }
+            });
           }
         }
       }

AsyncDisplayKit/Private/ASDisplayNodeInternal.h

@@ -82,7 +82,6 @@ FOUNDATION_EXPORT NSString * const ASRenderingEngineDidDisplayNodesScheduledBefo
     unsigned isEnteringHierarchy:1;
     unsigned isExitingHierarchy:1;
     unsigned isInHierarchy:1;
-    unsigned isMovingBetweenNodes:1;
     unsigned visibilityNotificationsDisabled:VISIBILITY_NOTIFICATIONS_DISABLED_BITS;
   } _flags;