Merge pull request #235 from ide/bridge-node

ASBridgeNode: wrapper around an existing UIView with ASDisplayNode semantics

AsyncDisplayKit/ASDisplayNode.h

@@ -12,6 +12,8 @@
 #import "ASBaseDefines.h"
 #import "ASDealloc2MainObject.h"
 
+typedef UIView *(^ASDisplayNodeViewBlock)();
+typedef CALayer *(^ASDisplayNodeLayerBlock)();
 
 /**
  * An `ASDisplayNode` is an abstraction over `UIView` and `CALayer` that allows you to perform calculations about a view
@@ -69,6 +71,22 @@
  */
 - (id)initWithLayerClass:(Class)layerClass;
 
+/**
+ * @abstract Alternative initializer with a block to create the backing view.
+ *
+ * @return An ASDisplayNode instance that loads its view with the given block that is guaranteed to run on the main
+ * queue. The view will render synchronously and -layout and touch handling methods on the node will not be called.
+ */
+- (id)initWithViewBlock:(ASDisplayNodeViewBlock)viewBlock;
+
+/**
+ * @abstract Alternative initializer with a block to create the backing layer.
+ *
+ * @return An ASDisplayNode instance that loads its layer with the given block that is guaranteed to run on the main
+ * queue. The layer will render synchronously and -layout and touch handling methods on the node will not be called.
+ */
+- (id)initWithLayerBlock:(ASDisplayNodeLayerBlock)viewBlock;
+
 
 /** @name Properties */
 

AsyncDisplayKit/ASDisplayNode.mm

@@ -181,6 +181,35 @@ void ASDisplayNodePerformBlockOnMainThread(void (^block)())
   return self;
 }
 
+- (id)initWithViewBlock:(ASDisplayNodeViewBlock)viewBlock
+{
+  if (!(self = [super init]))
+    return nil;
+
+  ASDisplayNodeAssertNotNil(viewBlock, @"should initialize with a valid block that returns a UIView");
+
+  [self _initializeInstance];
+  _viewBlock = viewBlock;
+  _flags.synchronous = YES;
+
+  return self;
+}
+
+- (id)initWithLayerBlock:(ASDisplayNodeLayerBlock)layerBlock
+{
+  if (!(self = [super init]))
+    return nil;
+
+  ASDisplayNodeAssertNotNil(layerBlock, @"should initialize with a valid block that returns a CALayer");
+
+  [self _initializeInstance];
+  _layerBlock = layerBlock;
+  _flags.synchronous = YES;
+  _flags.layerBacked = YES;
+
+  return self;
+}
+
 - (void)dealloc
 {
   ASDisplayNodeAssertMainThread();
@@ -249,6 +278,48 @@ void ASDisplayNodePerformBlockOnMainThread(void (^block)())
 
 }
 
+- (UIView *)_viewToLoad
+{
+  UIView *view;
+  ASDN::MutexLocker l(_propertyLock);
+
+  if (_viewBlock) {
+    view = _viewBlock();
+    ASDisplayNodeAssertNotNil(view, @"View block returned nil");
+    ASDisplayNodeAssert(![view isKindOfClass:[_ASDisplayView class]], @"View block should return a synchronously displayed view");
+    _viewBlock = nil;
+    _viewClass = [view class];
+  } else {
+    if (!_viewClass) {
+      _viewClass = [self.class viewClass];
+    }
+    view = [[_viewClass alloc] init];
+  }
+
+  return view;
+}
+
+- (CALayer *)_layerToLoad
+{
+  CALayer *layer;
+  ASDN::MutexLocker l(_propertyLock);
+
+  if (_layerBlock) {
+    layer = _layerBlock();
+    ASDisplayNodeAssertNotNil(layer, @"Layer block returned nil");
+    ASDisplayNodeAssert(![layer isKindOfClass:[_ASDisplayLayer class]], @"Layer block should return a synchronously displayed layer");
+    _layerBlock = nil;
+    _layerClass = [layer class];
+  } else {
+    if (!_layerClass) {
+      _layerClass = [self.class layerClass];
+    }
+    layer = [[_layerClass alloc] init];
+  }
+
+  return layer;
+}
+
 - (void)_loadViewOrLayerIsLayerBacked:(BOOL)isLayerBacked
 {
   ASDN::MutexLocker l(_propertyLock);
@@ -263,18 +334,11 @@ void ASDisplayNodePerformBlockOnMainThread(void (^block)())
 
   if (isLayerBacked) {
     TIME_SCOPED(_debugTimeToCreateView);
-    if (!_layerClass) {
+    _layer = [self _layerToLoad];
-      _layerClass = [self.class layerClass];
-    }
-
-    _layer = [[_layerClass alloc] init];
     _layer.delegate = self;
   } else {
     TIME_SCOPED(_debugTimeToCreateView);
-    if (!_viewClass) {
+    _view = [self _viewToLoad];
-      _viewClass = [self.class viewClass];
-    }
-    _view = [[_viewClass alloc] init];
     _view.asyncdisplaykit_node = self;
     _layer = _view.layer;
   }
@@ -363,6 +427,9 @@ void ASDisplayNodePerformBlockOnMainThread(void (^block)())
 
   ASDN::MutexLocker l(_propertyLock);
   ASDisplayNodeAssert(!_view && !_layer, @"Cannot change isLayerBacked after layer or view has loaded");
+  ASDisplayNodeAssert(!_viewBlock && !_layerBlock, @"Cannot change isLayerBacked when a layer or view block is provided");
+  ASDisplayNodeAssert(!_viewClass && !_layerClass, @"Cannot change isLayerBacked when a layer or view class is provided");
+
   if (isLayerBacked != _flags.layerBacked && !_view && !_layer) {
     _flags.layerBacked = isLayerBacked;
   }
@@ -1616,6 +1683,10 @@ static void _recursivelySetDisplaySuspended(ASDisplayNode *node, CALayer *layer,
     notableTargetDesc = [NSString stringWithFormat:@" [%@]", _viewClass];
   } else if (_layerClass) { // Nonstandard layer class unloaded
     notableTargetDesc = [NSString stringWithFormat:@" [%@]", _layerClass];
+  } else if (_viewBlock) { // Nonstandard lazy view unloaded
+    notableTargetDesc = @" [block]";
+  } else if (_layerBlock) { // Nonstandard lazy layer unloaded
+    notableTargetDesc = @" [block]";
   }
   if (self.name) {
     return [NSString stringWithFormat:@"<%@ %p name = %@%@>", self.class, self, self.name, notableTargetDesc];

AsyncDisplayKit/Private/ASDisplayNodeInternal.h

@@ -56,6 +56,8 @@ typedef NS_OPTIONS(NSUInteger, ASDisplayNodeMethodOverrides) {
   UIEdgeInsets _hitTestSlop;
   NSMutableArray *_subnodes;
 
+  ASDisplayNodeViewBlock _viewBlock;
+  ASDisplayNodeLayerBlock _layerBlock;
   Class _viewClass;
   Class _layerClass;
   UIView *_view;

AsyncDisplayKitTests/ASDisplayNodeTests.m

@@ -11,6 +11,7 @@
 #import <XCTest/XCTest.h>
 
 #import "_ASDisplayLayer.h"
+#import "_ASDisplayView.h"
 #import "ASDisplayNode+Subclasses.h"
 #import "ASDisplayNodeTestsHelper.h"
 #import "UIView+ASConvenience.h"
@@ -87,6 +88,12 @@ for (ASDisplayNode *n in @[ nodes ]) {\
 
 @end
 
+@interface UIDisplayNodeTestView : UIView
+@end
+
+@implementation UIDisplayNodeTestView
+@end
+
 @interface ASDisplayNodeTests : XCTestCase
 @end
 
@@ -118,6 +125,53 @@ for (ASDisplayNode *n in @[ nodes ]) {\
   XCTAssertNotNil(view, @"Getting node's view on-thread should succeed.");
 }
 
+- (void)testNodeCreatedOffThreadWithExistingView
+{
+  UIView *view = [[UIDisplayNodeTestView alloc] init];
+
+  __block ASDisplayNode *node = nil;
+  [self executeOffThread:^{
+    node = [[ASDisplayNode alloc] initWithViewBlock:^UIView *{
+      return view;
+    }];
+  }];
+
+  XCTAssertFalse(node.layerBacked, @"Can't be layer backed");
+  XCTAssertTrue(node.synchronous, @"Node with plain view should be synchronous");
+  XCTAssertFalse(node.nodeLoaded, @"Shouldn't have a view yet");
+  XCTAssertEqual(view, node.view, @"Getting node's view on-thread should succeed.");
+}
+
+- (void)testNodeCreatedOffThreadWithLazyView
+{
+  __block UIView *view = nil;
+  __block ASDisplayNode *node = nil;
+  [self executeOffThread:^{
+    node = [[ASDisplayNode alloc] initWithViewBlock:^UIView *{
+      XCTAssertTrue([NSThread isMainThread], @"View block must run on the main queue");
+      view = [[UIDisplayNodeTestView alloc] init];
+      return view;
+    }];
+  }];
+
+  XCTAssertNil(view, @"View block should not be invoked yet");
+  [node view];
+  XCTAssertNotNil(view, @"View block should have been invoked");
+  XCTAssertEqual(view, node.view, @"Getting node's view on-thread should succeed.");
+  XCTAssertTrue(node.synchronous, @"Node with plain view should be synchronous");
+}
+
+- (void)testNodeCreatedWithLazyAsyncView
+{
+  ASDisplayNode *node = [[ASDisplayNode alloc] initWithViewBlock:^UIView *{
+    XCTAssertTrue([NSThread isMainThread], @"View block must run on the main queue");
+    return [[_ASDisplayView alloc] init];
+  }];
+
+  XCTAssertThrows([node view], @"Externally provided views should be synchronous");
+  XCTAssertTrue(node.synchronous, @"Node with externally provided view should be synchronous");
+}
+
 - (void)checkValuesMatchDefaults:(ASDisplayNode *)node isLayerBacked:(BOOL)isLayerBacked
 {
   NSString *targetName = isLayerBacked ? @"layer" : @"view";
@@ -350,6 +404,92 @@ for (ASDisplayNode *n in @[ nodes ]) {\
   [self checkSimpleBridgePropertiesSetPropagate:YES];
 }
 
+- (void)testPropertiesSetOffThreadBeforeLoadingExternalView
+{
+  UIView *view = [[UIDisplayNodeTestView alloc] init];
+
+  __block ASDisplayNode *node = nil;
+  [self executeOffThread:^{
+    node = [[ASDisplayNode alloc] initWithViewBlock:^{
+      return view;
+    }];
+    node.backgroundColor = [UIColor blueColor];
+    node.frame = CGRectMake(10, 20, 30, 40);
+    node.autoresizingMask = UIViewAutoresizingFlexibleWidth;
+    node.userInteractionEnabled = YES;
+  }];
+
+  [self checkExternalViewAppliedPropertiesMatch:node];
+}
+
+- (void)testPropertiesSetOnThreadAfterLoadingExternalView
+{
+  UIView *view = [[UIDisplayNodeTestView alloc] init];
+  ASDisplayNode *node = [[ASDisplayNode alloc] initWithViewBlock:^{
+    return view;
+  }];
+
+  // Load the backing view first
+  [node view];
+
+  node.backgroundColor = [UIColor blueColor];
+  node.frame = CGRectMake(10, 20, 30, 40);
+  node.autoresizingMask = UIViewAutoresizingFlexibleWidth;
+  node.userInteractionEnabled = YES;
+
+  [self checkExternalViewAppliedPropertiesMatch:node];
+}
+
+- (void)checkExternalViewAppliedPropertiesMatch:(ASDisplayNode *)node
+{
+  UIView *view = node.view;
+
+  XCTAssertEqualObjects([UIColor blueColor], view.backgroundColor, @"backgroundColor not propagated to view");
+  XCTAssertTrue(CGRectEqualToRect(CGRectMake(10, 20, 30, 40), view.frame), @"frame not propagated to view");
+  XCTAssertEqual(UIViewAutoresizingFlexibleWidth, view.autoresizingMask, @"autoresizingMask not propagated to view");
+  XCTAssertEqual(YES, view.userInteractionEnabled, @"userInteractionEnabled not propagated to view");
+}
+
+- (void)testPropertiesSetOffThreadBeforeLoadingExternalLayer
+{
+  CALayer *layer = [[CAShapeLayer alloc] init];
+
+  __block ASDisplayNode *node = nil;
+  [self executeOffThread:^{
+    node = [[ASDisplayNode alloc] initWithLayerBlock:^{
+      return layer;
+    }];
+    node.backgroundColor = [UIColor blueColor];
+    node.frame = CGRectMake(10, 20, 30, 40);
+  }];
+
+  [self checkExternalLayerAppliedPropertiesMatch:node];
+}
+
+- (void)testPropertiesSetOnThreadAfterLoadingExternalLayer
+{
+  CALayer *layer = [[CAShapeLayer alloc] init];
+  ASDisplayNode *node = [[ASDisplayNode alloc] initWithLayerBlock:^{
+    return layer;
+  }];
+
+  // Load the backing layer first
+  [node layer];
+
+  node.backgroundColor = [UIColor blueColor];
+  node.frame = CGRectMake(10, 20, 30, 40);
+
+  [self checkExternalLayerAppliedPropertiesMatch:node];
+}
+
+- (void)checkExternalLayerAppliedPropertiesMatch:(ASDisplayNode *)node
+{
+  CALayer *layer = node.layer;
+
+  XCTAssertTrue(CGColorEqualToColor([UIColor blueColor].CGColor, layer.backgroundColor), @"backgroundColor not propagated to layer");
+  XCTAssertTrue(CGRectEqualToRect(CGRectMake(10, 20, 30, 40), layer.frame), @"frame not propagated to layer");
+}
+
 
 // Perform parallel updates of a standard UIView/CALayer and an ASDisplayNode and ensure they are equivalent.
 - (void)testDeriveFrameFromBoundsPositionAnchorPoint
@@ -1355,6 +1495,46 @@ static inline BOOL _CGPointEqualToPointWithEpsilon(CGPoint point1, CGPoint point
   [c release];
 }
 
+- (void)testSubnodeAddedBeforeLoadingExternalView
+{
+  UIView *view = [[UIDisplayNodeTestView alloc] init];
+
+  __block ASDisplayNode *parent = nil;
+  __block ASDisplayNode *child = nil;
+  [self executeOffThread:^{
+    parent = [[ASDisplayNode alloc] initWithViewBlock:^{
+      return view;
+    }];
+    child = [[ASDisplayNode alloc] init];
+    [parent addSubnode:child];
+  }];
+
+  XCTAssertEqual(1, parent.subnodes.count, @"Parent should have 1 subnode");
+  XCTAssertEqualObjects(parent, child.supernode, @"Child has the wrong parent");
+  XCTAssertEqual(0, view.subviews.count, @"View shouldn't have any subviews");
+
+  [parent view];
+
+  XCTAssertEqual(1, view.subviews.count, @"View should have 1 subview");
+}
+
+- (void)testSubnodeAddedAfterLoadingExternalView
+{
+  UIView *view = [[UIDisplayNodeTestView alloc] init];
+  ASDisplayNode *parent = [[ASDisplayNode alloc] initWithViewBlock:^{
+    return view;
+  }];
+
+  [parent view];
+
+  ASDisplayNode *child = [[ASDisplayNode alloc] init];
+  [parent addSubnode:child];
+
+  XCTAssertEqual(1, parent.subnodes.count, @"Parent should have 1 subnode");
+  XCTAssertEqualObjects(parent, child.supernode, @"Child has the wrong parent");
+  XCTAssertEqual(1, view.subviews.count, @"View should have 1 subview");
+}
+
 - (void)checkBackgroundColorOpaqueRelationshipWithViewLoaded:(BOOL)loaded layerBacked:(BOOL)isLayerBacked
 {
   ASDisplayNode *node = [[ASDisplayNode alloc] init];