Add method to cancel layout transitions in progress

- Also make sure a transition isn't invalidated right after it passed the validation test and before it proceeds
sainttail · Mar 21, 2016 · 9e76d7b · 9e76d7b
1 parent 1a57e2c
commit 9e76d7b
Show file tree

Hide file tree

Showing 2 changed files with 23 additions and 10 deletions.
diff --git a/AsyncDisplayKit/ASDisplayNode+Beta.h b/AsyncDisplayKit/ASDisplayNode+Beta.h
@@ -98,4 +98,9 @@ ASDISPLAYNODE_EXTERN_C_END
  */
 - (BOOL)placeholderShouldPersist;
 
+/**
+ * @abstract Cancels all performing layout transitions. Can be called on any thread.
+ */
+- (void)cancelLayoutTransitionsInProgress;
+
 @end
diff --git a/AsyncDisplayKit/ASDisplayNode.mm b/AsyncDisplayKit/ASDisplayNode.mm
@@ -593,14 +593,7 @@ - (ASLayout *)measureWithSizeRange:(ASSizeRange)constrainedSize
  return _layout;
  }
 
- if ([self _hasTransitionsInProgress]) {
- // Invalidate transition sentinel to cancel transitions in progress
- [self _invalidateTransitionSentinel];
- // Tell subnodes to exit layout pending state and clear related properties
- ASDisplayNodePerformBlockOnEverySubnode(self, ^(ASDisplayNode * _Nonnull node) {
- node.hierarchyState &= (~ASHierarchyStateLayoutPending);
- });
- }
+ [self cancelLayoutTransitionsInProgress];
 
  ASLayout *previousLayout = _layout;
  ASSizeRange previousConstrainedSize = _constrainedSize;
@@ -698,12 +691,14 @@ - (void)transitionLayoutWithSizeRange:(ASSizeRange)constrainedSize
  }
 
  ASPerformBlockOnMainThread(^{
+ // Grab _propertyLock here to make sure this transition isn't invalidated
+ // right after it passed the validation test and before it proceeds
+ ASDN::MutexLocker l(_propertyLock);
+
  if ([self _shouldAbortTransitionWithID:transitionID]) {
  return;
  }
 
- ASDN::MutexLocker l(_propertyLock);
-
  ASLayout *previousLayout = _layout;
  ASSizeRange previousConstrainedSize = _constrainedSize;
  [self applyLayout:newLayout constrainedSize:constrainedSize layoutContext:nil];
@@ -769,6 +764,19 @@ - (void)calculatedLayoutDidChange
  // subclass override
 }
 
+- (void)cancelLayoutTransitionsInProgress
+{
+ ASDN::MutexLocker l(_propertyLock);
+ if ([self _hasTransitionsInProgress]) {
+ // Invalidate transition sentinel to cancel transitions in progress
+ [self _invalidateTransitionSentinel];
+ // Tell subnodes to exit layout pending state and clear related properties
+ ASDisplayNodePerformBlockOnEverySubnode(self, ^(ASDisplayNode * _Nonnull node) {
+ node.hierarchyState &= (~ASHierarchyStateLayoutPending);
+ });
+ }
+}
+
 #pragma mark - Layout Transition
 
 - (BOOL)usesImplicitHierarchyManagement