Improve separation of code for layout method types

AsyncDisplayKit.xcodeproj/project.pbxproj

@@ -207,6 +207,9 @@
 		9C8898BD1C738BB800D6B02E /* ASTextKitFontSizeAdjuster.h in Headers */ = {isa = PBXBuildFile; fileRef = A32FEDD31C501B6A004F642A /* ASTextKitFontSizeAdjuster.h */; settings = {ATTRIBUTES = (Private, ); }; };
 		9CC606651D24DF9E006581A0 /* NSIndexSet+ASHelpers.mm in Sources */ = {isa = PBXBuildFile; fileRef = CC4981BB1D1C7F65004E13CC /* NSIndexSet+ASHelpers.mm */; };
 		9CDC18CD1B910E12004965E2 /* ASLayoutElementPrivate.h in Headers */ = {isa = PBXBuildFile; fileRef = 9CDC18CB1B910E12004965E2 /* ASLayoutElementPrivate.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		9D9AA56921E23EE200172C09 /* ASDisplayNode+LayoutSpec.mm in Sources */ = {isa = PBXBuildFile; fileRef = 9D9AA56721E23EE200172C09 /* ASDisplayNode+LayoutSpec.mm */; };
+		9D9AA56B21E254B800172C09 /* ASDisplayNode+Yoga.h in Headers */ = {isa = PBXBuildFile; fileRef = 9D9AA56A21E254B800172C09 /* ASDisplayNode+Yoga.h */; };
+		9D9AA56D21E2568500172C09 /* ASDisplayNode+LayoutSpec.h in Headers */ = {isa = PBXBuildFile; fileRef = 9D9AA56C21E2568500172C09 /* ASDisplayNode+LayoutSpec.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		9F06E5CD1B4CAF4200F015D8 /* ASCollectionViewTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 9F06E5CC1B4CAF4200F015D8 /* ASCollectionViewTests.mm */; };
 		9F98C0261DBE29E000476D92 /* ASControlTargetAction.mm in Sources */ = {isa = PBXBuildFile; fileRef = 9F98C0241DBDF2A300476D92 /* ASControlTargetAction.mm */; };
 		9F98C0271DBE29FC00476D92 /* ASControlTargetAction.h in Headers */ = {isa = PBXBuildFile; fileRef = 9F98C0231DBDF2A300476D92 /* ASControlTargetAction.h */; settings = {ATTRIBUTES = (Private, ); }; };
@@ -774,6 +777,9 @@
 		9CDC18CB1B910E12004965E2 /* ASLayoutElementPrivate.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASLayoutElementPrivate.h; sourceTree = "<group>"; };
 		9CFFC6BF1CCAC73C006A6476 /* ASViewController.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASViewController.mm; sourceTree = "<group>"; };
 		9CFFC6C11CCAC768006A6476 /* ASTableNode.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASTableNode.mm; sourceTree = "<group>"; };
+		9D9AA56721E23EE200172C09 /* ASDisplayNode+LayoutSpec.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = "ASDisplayNode+LayoutSpec.mm"; sourceTree = "<group>"; };
+		9D9AA56A21E254B800172C09 /* ASDisplayNode+Yoga.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "ASDisplayNode+Yoga.h"; sourceTree = "<group>"; };
+		9D9AA56C21E2568500172C09 /* ASDisplayNode+LayoutSpec.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "ASDisplayNode+LayoutSpec.h"; sourceTree = "<group>"; };
 		9F06E5CC1B4CAF4200F015D8 /* ASCollectionViewTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; lineEnding = 0; path = ASCollectionViewTests.mm; sourceTree = "<group>"; xcLanguageSpecificationIdentifier = xcode.lang.objc; };
 		9F98C0231DBDF2A300476D92 /* ASControlTargetAction.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASControlTargetAction.h; sourceTree = "<group>"; };
 		9F98C0241DBDF2A300476D92 /* ASControlTargetAction.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASControlTargetAction.mm; sourceTree = "<group>"; };
@@ -1209,6 +1215,9 @@
 				683F563620E409D600CEB7A3 /* ASDisplayNode+InterfaceState.h */,
 				69BCE3D71EC6513B007DCCAD /* ASDisplayNode+Layout.mm */,
 				058D09DA195D050800B7D73C /* ASDisplayNode+Subclasses.h */,
+				9D9AA56C21E2568500172C09 /* ASDisplayNode+LayoutSpec.h */,
+				9D9AA56721E23EE200172C09 /* ASDisplayNode+LayoutSpec.mm */,
+				9D9AA56A21E254B800172C09 /* ASDisplayNode+Yoga.h */,
 				90FC784E1E4BFE1B00383C5A /* ASDisplayNode+Yoga.mm */,
 				058D09DB195D050800B7D73C /* ASDisplayNodeExtras.h */,
 				058D09DC195D050800B7D73C /* ASDisplayNodeExtras.mm */,
@@ -1887,6 +1896,7 @@
 				CCBDDD0520C62A2D00CBA922 /* ASMainThreadDeallocation.h in Headers */,
 				CCAA0B7F206ADBF30057B336 /* ASRecursiveUnfairLock.h in Headers */,
 				E5E281741E71C833006B67C2 /* ASCollectionLayoutState.h in Headers */,
+				9D9AA56D21E2568500172C09 /* ASDisplayNode+LayoutSpec.h in Headers */,
 				E5B077FF1E69F4EB00C24B5B /* ASElementMap.h in Headers */,
 				CCCCCCE31EC3EF060087FE10 /* NSParagraphStyle+ASText.h in Headers */,
 				E58E9E441E941D74004CFC59 /* ASCollectionLayoutContext.h in Headers */,
@@ -2018,6 +2028,7 @@
 				B35062531B010EFD0018CF92 /* ASImageNode+CGExtras.h in Headers */,
 				E58E9E491E941DA5004CFC59 /* ASCollectionLayout.h in Headers */,
 				254C6B7F1BF94DF4003EC431 /* ASTextKitTruncating.h in Headers */,
+				9D9AA56B21E254B800172C09 /* ASDisplayNode+Yoga.h in Headers */,
 				CC58AA4B1E398E1D002C8CB4 /* ASBlockTypes.h in Headers */,
 				CCA282BC1E9EABDD0037E8B7 /* ASTipProvider.h in Headers */,
 				6977965F1D8AC8D3007E93D7 /* ASLayoutSpec+Subclasses.h in Headers */,
@@ -2395,6 +2406,7 @@
 				CCDC9B4E200991D10063C1F8 /* ASGraphicsContext.mm in Sources */,
 				CCCCCCD81EC3EF060087FE10 /* ASTextInput.mm in Sources */,
 				34EFC7621B701CA400AD841F /* ASBackgroundLayoutSpec.mm in Sources */,
+				9D9AA56921E23EE200172C09 /* ASDisplayNode+LayoutSpec.mm in Sources */,
 				DE8BEAC41C2DF3FC00D57C12 /* ASDelegateProxy.mm in Sources */,
 				B35062141B010EFD0018CF92 /* ASBasicImageDownloader.mm in Sources */,
 				B35062161B010EFD0018CF92 /* ASBatchContext.mm in Sources */,

Source/ASCellNode.mm

@@ -17,7 +17,6 @@
 #import <AsyncDisplayKit/ASTableView+Undeprecated.h>
 #import <AsyncDisplayKit/_ASDisplayView.h>
 #import <AsyncDisplayKit/ASDisplayNode+Subclasses.h>
-#import <AsyncDisplayKit/ASDisplayNode+Beta.h>
 #import <AsyncDisplayKit/ASTextNode.h>
 #import <AsyncDisplayKit/ASCollectionNode.h>
 #import <AsyncDisplayKit/ASTableNode.h>

Source/ASDisplayNode+Beta.h

@@ -15,6 +15,7 @@
 #if YOGA
   #import YOGA_HEADER_PATH
   #import <AsyncDisplayKit/ASYogaUtilities.h>
+  #import <AsyncDisplayKit/ASDisplayNode+Yoga.h>
 #endif
 
 NS_ASSUME_NONNULL_BEGIN
@@ -180,63 +181,4 @@ typedef struct {
 
 @end
 
-#pragma mark - Yoga Layout Support
-
-#if YOGA
-
-AS_EXTERN void ASDisplayNodePerformBlockOnEveryYogaChild(ASDisplayNode * _Nullable node, void(^block)(ASDisplayNode *node));
-
-@interface ASDisplayNode (Yoga)
-
-@property (copy) NSArray *yogaChildren;
-
-- (void)addYogaChild:(ASDisplayNode *)child;
-- (void)removeYogaChild:(ASDisplayNode *)child;
-- (void)insertYogaChild:(ASDisplayNode *)child atIndex:(NSUInteger)index;
-
-- (void)semanticContentAttributeDidChange:(UISemanticContentAttribute)attribute;
-
-@property BOOL yogaLayoutInProgress;
-// TODO: Make this atomic (lock).
-@property (nullable, nonatomic) ASLayout *yogaCalculatedLayout;
-
-// Will walk up the Yoga tree and returns the root node
-- (ASDisplayNode *)yogaRoot;
-
-// These methods are intended to be used internally to Texture, and should not be called directly.
-- (BOOL)shouldHaveYogaMeasureFunc;
-- (void)invalidateCalculatedYogaLayout;
-- (void)calculateLayoutFromYogaRoot:(ASSizeRange)rootConstrainedSize;
-
-@end
-
-@interface ASDisplayNode (YogaDebugging)
-
-- (NSString *)yogaTreeDescription;
-
-@end
-
-@interface ASLayoutElementStyle (Yoga)
-
-- (YGNodeRef)yogaNodeCreateIfNeeded;
-- (void)destroyYogaNode;
-
-@property (readonly) YGNodeRef yogaNode;
-
-@property ASStackLayoutDirection flexDirection;
-@property YGDirection direction;
-@property ASStackLayoutJustifyContent justifyContent;
-@property ASStackLayoutAlignItems alignItems;
-@property YGPositionType positionType;
-@property ASEdgeInsets position;
-@property ASEdgeInsets margin;
-@property ASEdgeInsets padding;
-@property ASEdgeInsets border;
-@property CGFloat aspectRatio;
-@property YGWrap flexWrap;
-
-@end
-
-#endif
-
 NS_ASSUME_NONNULL_END

Source/ASDisplayNode+Layout.mm

@@ -7,6 +7,7 @@
 //  Licensed under Apache 2.0: http://www.apache.org/licenses/LICENSE-2.0
 //
 
+#import <AsyncDisplayKit/ASAvailability.h>
 #import <AsyncDisplayKit/ASDisplayNodeExtras.h>
 #import <AsyncDisplayKit/ASDisplayNodeInternal.h>
 #import <AsyncDisplayKit/ASDisplayNode+FrameworkPrivate.h>
@@ -143,19 +144,19 @@ - (NSString *)asciiArtName
 
 @implementation ASDisplayNode (ASLayout)
 
-- (void)setLayoutSpecBlock:(ASLayoutSpecBlock)layoutSpecBlock
+- (ASLayoutEngineType)layoutEngineType
 {
-  // For now there should never be an override of layoutSpecThatFits: and a layoutSpecBlock together.
-  ASDisplayNodeAssert(!(_methodOverrides & ASDisplayNodeMethodOverrideLayoutSpecThatFits),
-                      @"Nodes with a .layoutSpecBlock must not also implement -layoutSpecThatFits:");
+#if YOGA
   ASDN::MutexLocker l(__instanceLock__);
-  _layoutSpecBlock = layoutSpecBlock;
-}
+  YGNodeRef yogaNode = _style.yogaNode;
+  BOOL hasYogaParent = (_yogaParent != nil);
+  BOOL hasYogaChildren = (_yogaChildren.count > 0);
+  if (yogaNode != NULL && (hasYogaParent || hasYogaChildren)) {
+    return ASLayoutEngineTypeYoga;
+  }
+#endif
 
-- (ASLayoutSpecBlock)layoutSpecBlock
-{
-  ASDN::MutexLocker l(__instanceLock__);
-  return _layoutSpecBlock;
+  return ASLayoutEngineTypeLayoutSpec;
 }
 
 - (ASLayout *)calculatedLayout

Source/ASDisplayNode+LayoutSpec.h

@@ -0,0 +1,66 @@
+//
+//  ASDisplayNode+LayoutSpec.h
+//  Texture
+//
+//  Copyright (c) Pinterest, Inc.  All rights reserved.
+//  Licensed under Apache 2.0: http://www.apache.org/licenses/LICENSE-2.0
+//
+
+#import <AsyncDisplayKit/ASDisplayNode.h>
+#import <AsyncDisplayKit/ASDimension.h>
+
+@class ASLayout;
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface ASDisplayNode (ASLayoutSpec)
+
+/**
+ * @abstract Provides a way to declare a block to provide an ASLayoutSpec without having to subclass ASDisplayNode and
+ * implement layoutSpecThatFits:
+ *
+ * @return A block that takes a constrainedSize ASSizeRange argument, and must return an ASLayoutSpec that includes all
+ * of the subnodes to position in the layout. This input-output relationship is identical to the subclass override
+ * method -layoutSpecThatFits:
+ *
+ * @warning Subclasses that implement -layoutSpecThatFits: must not also use .layoutSpecBlock. Doing so will trigger
+ * an exception. A future version of the framework may support using both, calling them serially, with the
+ * .layoutSpecBlock superseding any values set by the method override.
+ *
+ * @code ^ASLayoutSpec *(__kindof ASDisplayNode * _Nonnull node, ASSizeRange constrainedSize) {};
+ */
+@property (nullable) ASLayoutSpecBlock layoutSpecBlock;
+
+@end
+
+// These methods are intended to be used internally to Texture, and should not be called directly.
+@interface ASDisplayNode (ASLayoutSpecPrivate)
+
+///  For internal usage only
+- (ASLayout *)calculateLayoutLayoutSpec:(ASSizeRange)constrainedSize;
+
+@end
+
+@interface ASDisplayNode (ASLayoutSpecSubclasses)
+
+/**
+ * @abstract Return a layout spec that describes the layout of the receiver and its children.
+ *
+ * @param constrainedSize The minimum and maximum sizes the receiver should fit in.
+ *
+ * @discussion Subclasses that override should expect this method to be called on a non-main thread. The returned layout spec
+ * is used to calculate an ASLayout and cached by ASDisplayNode for quick access during -layout. Other expensive work that needs to
+ * be done before display can be performed here, and using ivars to cache any valuable intermediate results is
+ * encouraged.
+ *
+ * @note This method should not be called directly outside of ASDisplayNode; use -layoutThatFits: instead.
+ *
+ * @warning Subclasses that implement -layoutSpecThatFits: must not use .layoutSpecBlock. Doing so will trigger an
+ * exception. A future version of the framework may support using both, calling them serially, with the .layoutSpecBlock
+ * superseding any values set by the method override.
+ */
+- (ASLayoutSpec *)layoutSpecThatFits:(ASSizeRange)constrainedSize;
+
+@end
+
+NS_ASSUME_NONNULL_END

Source/ASDisplayNode+LayoutSpec.mm

@@ -0,0 +1,146 @@
+//
+//  ASDisplayNode+LayoutSpec.mm
+//  Texture
+//
+//  Copyright (c) Pinterest, Inc.  All rights reserved.
+//  Licensed under Apache 2.0: http://www.apache.org/licenses/LICENSE-2.0
+//
+
+#import <UIKit/UIKit.h>
+#import <AsyncDisplayKit/ASAvailability.h>
+
+#import <AsyncDisplayKit/_ASScopeTimer.h>
+#import <AsyncDisplayKit/ASDisplayNodeInternal.h>
+#import <AsyncDisplayKit/ASDisplayNode+Subclasses.h>
+#import <AsyncDisplayKit/ASLayout.h>
+#import <AsyncDisplayKit/ASLayoutSpec+Subclasses.h>
+#import <AsyncDisplayKit/ASLayoutSpecPrivate.h>
+#import <AsyncDisplayKit/ASLog.h>
+#import <AsyncDisplayKit/ASThread.h>
+
+
+@implementation ASDisplayNode (ASLayoutSpec)
+
+- (void)setLayoutSpecBlock:(ASLayoutSpecBlock)layoutSpecBlock
+{
+  // For now there should never be an override of layoutSpecThatFits: and a layoutSpecBlock together.
+  ASDisplayNodeAssert(!(_methodOverrides & ASDisplayNodeMethodOverrideLayoutSpecThatFits),
+                      @"Nodes with a .layoutSpecBlock must not also implement -layoutSpecThatFits:");
+  ASDN::MutexLocker l(__instanceLock__);
+  _layoutSpecBlock = layoutSpecBlock;
+}
+
+- (ASLayoutSpecBlock)layoutSpecBlock
+{
+  ASDN::MutexLocker l(__instanceLock__);
+  return _layoutSpecBlock;
+}
+
+- (ASLayout *)calculateLayoutLayoutSpec:(ASSizeRange)constrainedSize
+{
+  ASDN::UniqueLock l(__instanceLock__);
+
+  // Manual size calculation via calculateSizeThatFits:
+  if (_layoutSpecBlock == NULL && (_methodOverrides & ASDisplayNodeMethodOverrideLayoutSpecThatFits) == 0) {
+    CGSize size = [self calculateSizeThatFits:constrainedSize.max];
+    ASDisplayNodeLogEvent(self, @"calculatedSize: %@", NSStringFromCGSize(size));
+    return [ASLayout layoutWithLayoutElement:self size:ASSizeRangeClamp(constrainedSize, size) sublayouts:nil];
+  }
+
+  // Size calcualtion with layout elements
+  BOOL measureLayoutSpec = _measurementOptions & ASDisplayNodePerformanceMeasurementOptionLayoutSpec;
+  if (measureLayoutSpec) {
+    _layoutSpecNumberOfPasses++;
+  }
+
+  // Get layout element from the node
+  id<ASLayoutElement> layoutElement = [self _locked_layoutElementThatFits:constrainedSize];
+#if ASEnableVerboseLogging
+  for (NSString *asciiLine in [[layoutElement asciiArtString] componentsSeparatedByString:@"\n"]) {
+    as_log_verbose(ASLayoutLog(), "%@", asciiLine);
+  }
+#endif
+
+
+  // Certain properties are necessary to set on an element of type ASLayoutSpec
+  if (layoutElement.layoutElementType == ASLayoutElementTypeLayoutSpec) {
+    ASLayoutSpec *layoutSpec = (ASLayoutSpec *)layoutElement;
+
+#if AS_DEDUPE_LAYOUT_SPEC_TREE
+    NSHashTable *duplicateElements = [layoutSpec findDuplicatedElementsInSubtree];
+    if (duplicateElements.count > 0) {
+      ASDisplayNodeFailAssert(@"Node %@ returned a layout spec that contains the same elements in multiple positions. Elements: %@", self, duplicateElements);
+      // Use an empty layout spec to avoid crashes
+      layoutSpec = [[ASLayoutSpec alloc] init];
+    }
+#endif
+
+    ASDisplayNodeAssert(layoutSpec.isMutable, @"Node %@ returned layout spec %@ that has already been used. Layout specs should always be regenerated.", self, layoutSpec);
+
+    layoutSpec.isMutable = NO;
+  }
+
+  // Manually propagate the trait collection here so that any layoutSpec children of layoutSpec will get a traitCollection
+  {
+    ASDN::SumScopeTimer t(_layoutSpecTotalTime, measureLayoutSpec);
+    ASTraitCollectionPropagateDown(layoutElement, self.primitiveTraitCollection);
+  }
+
+  BOOL measureLayoutComputation = _measurementOptions & ASDisplayNodePerformanceMeasurementOptionLayoutComputation;
+  if (measureLayoutComputation) {
+    _layoutComputationNumberOfPasses++;
+  }
+
+  // Layout element layout creation
+  ASLayout *layout = ({
+    ASDN::SumScopeTimer t(_layoutComputationTotalTime, measureLayoutComputation);
+    [layoutElement layoutThatFits:constrainedSize];
+  });
+  ASDisplayNodeAssertNotNil(layout, @"[ASLayoutElement layoutThatFits:] should never return nil! %@, %@", self, layout);
+
+  // Make sure layoutElementObject of the root layout is `self`, so that the flattened layout will be structurally correct.
+  BOOL isFinalLayoutElement = (layout.layoutElement != self);
+  if (isFinalLayoutElement) {
+    layout.position = CGPointZero;
+    layout = [ASLayout layoutWithLayoutElement:self size:layout.size sublayouts:@[layout]];
+  }
+  ASDisplayNodeLogEvent(self, @"computedLayout: %@", layout);
+
+  // PR #1157: Reduces accuracy of _unflattenedLayout for debugging/Weaver
+  if ([ASDisplayNode shouldStoreUnflattenedLayouts]) {
+    _unflattenedLayout = layout;
+  }
+  layout = [layout filteredNodeLayoutTree];
+
+  return layout;
+}
+
+- (id<ASLayoutElement>)_locked_layoutElementThatFits:(ASSizeRange)constrainedSize
+{
+  ASAssertLocked(__instanceLock__);
+
+  BOOL measureLayoutSpec = _measurementOptions & ASDisplayNodePerformanceMeasurementOptionLayoutSpec;
+
+  if (_layoutSpecBlock != NULL) {
+    return ({
+      ASDN::MutexLocker l(__instanceLock__);
+      ASDN::SumScopeTimer t(_layoutSpecTotalTime, measureLayoutSpec);
+      _layoutSpecBlock(self, constrainedSize);
+    });
+  } else {
+    return ({
+      ASDN::SumScopeTimer t(_layoutSpecTotalTime, measureLayoutSpec);
+      [self layoutSpecThatFits:constrainedSize];
+    });
+  }
+}
+
+- (ASLayoutSpec *)layoutSpecThatFits:(ASSizeRange)constrainedSize
+{
+  __ASDisplayNodeCheckForLayoutMethodOverrides;
+
+  ASDisplayNodeAssert(NO, @"-[ASDisplayNode layoutSpecThatFits:] should never return an empty value. One way this is caused is by calling -[super layoutSpecThatFits:] which is not currently supported.");
+  return [[ASLayoutSpec alloc] init];
+}
+
+@end