Several small optimizations, especially to _ASPendingState and other hot paths.

Author: Scott Goodson

AsyncDisplayKit/ASControlNode.m

@@ -76,7 +76,6 @@ - (id)init
   if (!(self = [super init]))
     return nil;
 
-  _controlEventDispatchTable = [[NSMutableDictionary alloc] initWithCapacity:kASControlNodeEventDispatchTableInitialCapacity]; // enough to handle common types without re-hashing the dictionary when adding entries.
   _enabled = YES;
 
   // As we have no targets yet, we start off with user interaction off. When a target is added, it'll get turned back on.
@@ -214,6 +213,10 @@ - (void)addTarget:(id)target action:(SEL)action forControlEvents:(ASControlNodeE
   // Convert nil to [NSNull null] so that it can be used as a key for NSMapTable.
   if (!target)
     target = [NSNull null];
+  
+  if (!_controlEventDispatchTable) {
+    _controlEventDispatchTable = [[NSMutableDictionary alloc] initWithCapacity:kASControlNodeEventDispatchTableInitialCapacity]; // enough to handle common types without re-hashing the dictionary when adding entries.
+  }
 
   // Enumerate the events in the mask, adding the target-action pair for each control event included in controlEventMask
   _ASEnumerateControlEventsIncludedInMaskWithBlock(controlEventMask, ^

AsyncDisplayKit/ASDisplayNode.mm

@@ -1470,9 +1470,9 @@ - (BOOL)_pendingDisplayNodesHaveFinished
 }
 
 // Helper method to summarize whether or not the node run through the display process
-- (BOOL)_implementsDisplay
+- (BOOL)__implementsDisplay
 {
-  return _flags.implementsDrawRect == YES || _flags.implementsImageDisplay == YES;
+  return _flags.implementsDrawRect == YES || _flags.implementsImageDisplay == YES || self.shouldRasterizeDescendants;
 }
 
 - (void)_setupPlaceholderLayer
@@ -1502,7 +1502,7 @@ void recursivelyTriggerDisplayForLayer(CALayer *layer, BOOL shouldBlock)
   // (even a runloop observer at a late call order will not stop the next frame from compositing, showing placeholders).
 
   ASDisplayNode *node = [layer asyncdisplaykit_node];
-  if (!layer.contents && [node _implementsDisplay]) {
+  if (!layer.contents && [node __implementsDisplay]) {
     // For layers that do get displayed here, this immediately kicks off the work on the concurrent -[_ASDisplayLayer displayQueue].
     // At the same time, it creates an associated _ASAsyncTransaction, which we can use to block on display completion.  See ASDisplayNode+AsyncDisplay.mm.
     [layer displayIfNeeded];
@@ -2148,7 +2148,7 @@ - (void)setDisplaySuspended:(BOOL)flag
 
   self.asyncLayer.displaySuspended = flag;
 
-  if ([self _implementsDisplay]) {
+  if ([self __implementsDisplay]) {
     if (flag) {
       [_supernode subnodeDisplayDidFinish:self];
     } else {

AsyncDisplayKit/ASPagerNode.m

@@ -20,13 +20,14 @@ @implementation ASPagerNode
 
 - (instancetype)init
 {
-  _flowLayout = [[UICollectionViewFlowLayout alloc] init];
-  _flowLayout.scrollDirection = UICollectionViewScrollDirectionHorizontal;
-  _flowLayout.minimumInteritemSpacing = 0;
-  _flowLayout.minimumLineSpacing = 0;
+  UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
+  flowLayout.scrollDirection = UICollectionViewScrollDirectionHorizontal;
+  flowLayout.minimumInteritemSpacing = 0;
+  flowLayout.minimumLineSpacing = 0;
 
-  self = [super initWithCollectionViewLayout:_flowLayout];
+  self = [super initWithCollectionViewLayout:flowLayout];
   if (self != nil) {
+    _flowLayout = flowLayout;
   }
   return self;
 }

AsyncDisplayKit/ASTextNode.mm

@@ -97,6 +97,8 @@ @implementation ASTextNode {
 
 #pragma mark - NSObject
 
+static NSArray *DefaultLinkAttributeNames = @[ NSLinkAttributeName ];
+
 - (instancetype)init
 {
   if (self = [super init]) {
@@ -120,7 +122,7 @@ - (instancetype)init
     self.opaque = NO;
     self.backgroundColor = [UIColor clearColor];
 
-    self.linkAttributeNames = @[ NSLinkAttributeName ];
+    self.linkAttributeNames = DefaultLinkAttributeNames;
 
     // Accessibility
     self.isAccessibilityElement = YES;

AsyncDisplayKit/Private/ASDisplayNode+AsyncDisplay.mm

@@ -175,8 +175,6 @@ - (void)_recursivelyRasterizeSelfAndSublayersWithIsCancelledBlock:(asdisplaynode
 
 - (asyncdisplaykit_async_transaction_operation_block_t)_displayBlockWithAsynchronous:(BOOL)asynchronous isCancelledBlock:(asdisplaynode_iscancelled_block_t)isCancelledBlock rasterizing:(BOOL)rasterizing
 {
-  id nodeClass = [self class];
-
   asyncdisplaykit_async_transaction_operation_block_t displayBlock = nil;
 
   ASDisplayNodeAssert(rasterizing || !(_hierarchyState & ASHierarchyStateRasterized), @"Rasterized descendants should never display unless being drawn into the rasterized container.");
@@ -235,7 +233,7 @@ - (asyncdisplaykit_async_transaction_operation_block_t)_displayBlockWithAsynchro
 
       ASDN_DELAY_FOR_DISPLAY();
 
-      UIImage *result = [nodeClass displayWithParameters:drawParameters isCancelled:isCancelledBlock];
+      UIImage *result = [[self class] displayWithParameters:drawParameters isCancelled:isCancelledBlock];
       __ASDisplayLayerDecrementConcurrentDisplayCount(asynchronous, rasterizing);
       return result;
     };
@@ -265,7 +263,7 @@ - (asyncdisplaykit_async_transaction_operation_block_t)_displayBlockWithAsynchro
         UIGraphicsBeginImageContextWithOptions(bounds.size, opaque, contentsScaleForDisplay);
       }
 
-      [nodeClass drawRect:bounds withParameters:drawParameters isCancelled:isCancelledBlock isRasterizing:rasterizing];
+      [[self class] drawRect:bounds withParameters:drawParameters isCancelled:isCancelledBlock isRasterizing:rasterizing];
 
       if (isCancelledBlock()) {
         if (!rasterizing) {

AsyncDisplayKit/Private/ASDisplayNodeInternal.h

@@ -144,6 +144,9 @@ typedef NS_OPTIONS(NSUInteger, ASDisplayNodeMethodOverrides)
 // Call didExitHierarchy if necessary and set inHierarchy = NO if visibility notifications are enabled on all of its parents
 - (void)__exitHierarchy;
 
+// Helper method to summarize whether or not the node run through the display process
+- (BOOL)__implementsDisplay;
+
 // Display the node's view/layer immediately on the current thread, bypassing the background thread rendering. Will be deprecated.
 - (void)displayImmediately;
 

AsyncDisplayKit/Private/_ASPendingState.m

@@ -135,19 +135,24 @@ @implementation _ASPendingState
 @synthesize borderColor=borderColor;
 @synthesize asyncdisplaykit_asyncTransactionContainer=asyncTransactionContainer;
 
+
+static CGColorRef blackColorRef = NULL;
+static UIColor *defaultTintColor = nil;
+
 - (id)init
 {
   if (!(self = [super init]))
     return nil;
 
-  // Default UIKit color is an RGB color
-  static CGColorRef black;
+
   static dispatch_once_t onceToken;
   dispatch_once(&onceToken, ^{
+    // Default UIKit color is an RGB color
     CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
-    black = CGColorCreate(colorSpace, (CGFloat[]){0,0,0,1} );
-    CFRetain(black);
+    blackColorRef = CGColorCreate(colorSpace, (CGFloat[]){0,0,0,1} );
+    CFRetain(blackColorRef);
     CGColorSpaceRelease(colorSpace);
+    defaultTintColor = [UIColor colorWithRed:0.0 green:0.478 blue:1.0 alpha:1.0];
   });
 
   // Set defaults, these come from the defaults specified in CALayer and UIView
@@ -156,7 +161,7 @@ - (id)init
   frame = CGRectZero;
   bounds = CGRectZero;
   backgroundColor = nil;
-  tintColor = [UIColor colorWithRed:0.0 green:0.478 blue:1.0 alpha:1.0];
+  tintColor = defaultTintColor;
   contents = nil;
   isHidden = NO;
   needsDisplayOnBoundsChange = NO;
@@ -172,14 +177,12 @@ - (id)init
   transform = CATransform3DIdentity;
   sublayerTransform = CATransform3DIdentity;
   userInteractionEnabled = YES;
-  CFRetain(black);
-  shadowColor = black;
+  shadowColor = blackColorRef;
   shadowOpacity = 0.0;
   shadowOffset = CGSizeMake(0, -3);
   shadowRadius = 3;
   borderWidth = 0;
-  CFRetain(black);
-  borderColor = black;
+  borderColor = blackColorRef;
   isAccessibilityElement = NO;
   accessibilityLabel = nil;
   accessibilityHint = nil;
@@ -376,7 +379,9 @@ - (void)setShadowColor:(CGColorRef)color
     return;
   }
 
-  CGColorRelease(shadowColor);
+  if (shadowColor != blackColorRef) {
+    CGColorRelease(shadowColor);
+  }
   shadowColor = color;
   CGColorRetain(shadowColor);
 
@@ -413,7 +418,9 @@ - (void)setBorderColor:(CGColorRef)color
     return;
   }
 
-  CGColorRelease(borderColor);
+  if (borderColor != blackColorRef) {
+    CGColorRelease(borderColor);
+  }
   borderColor = color;
   CGColorRetain(borderColor);
 
@@ -1002,8 +1009,14 @@ + (_ASPendingState *)pendingViewStateFromView:(UIView *)view
 - (void)dealloc
 {
   CGColorRelease(backgroundColor);
-  CGColorRelease(shadowColor);
-  CGColorRelease(borderColor);
+  
+  if (shadowColor != blackColorRef) {
+    CGColorRelease(shadowColor);
+  }
+  
+  if (borderColor != blackColorRef) {
+    CGColorRelease(borderColor);
+  }
 }
 
 @end