Merge pull request #1456 from maicki/ASEnvironment

[ASEnvironment] Add support for ASEnvironment, supporting generalized state propagation both up and down node and layout spec trees.

AsyncDisplayKit.xcodeproj/project.pbxproj

@@ -258,6 +258,16 @@
 		68EE0DBE1C1B4ED300BA1B99 /* ASMainSerialQueue.h in Headers */ = {isa = PBXBuildFile; fileRef = 68EE0DBB1C1B4ED300BA1B99 /* ASMainSerialQueue.h */; };
 		68EE0DBF1C1B4ED300BA1B99 /* ASMainSerialQueue.mm in Sources */ = {isa = PBXBuildFile; fileRef = 68EE0DBC1C1B4ED300BA1B99 /* ASMainSerialQueue.mm */; };
 		68EE0DC01C1B4ED300BA1B99 /* ASMainSerialQueue.mm in Sources */ = {isa = PBXBuildFile; fileRef = 68EE0DBC1C1B4ED300BA1B99 /* ASMainSerialQueue.mm */; };
+		698548631CA9E025008A345F /* ASEnvironment.h in Headers */ = {isa = PBXBuildFile; fileRef = 698548611CA9E025008A345F /* ASEnvironment.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		698548641CA9E025008A345F /* ASEnvironment.h in Headers */ = {isa = PBXBuildFile; fileRef = 698548611CA9E025008A345F /* ASEnvironment.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		698548651CA9E025008A345F /* ASEnvironment.m in Sources */ = {isa = PBXBuildFile; fileRef = 698548621CA9E025008A345F /* ASEnvironment.m */; };
+		698548661CA9E025008A345F /* ASEnvironment.m in Sources */ = {isa = PBXBuildFile; fileRef = 698548621CA9E025008A345F /* ASEnvironment.m */; };
+		698C8B611CAB49FC0052DC3F /* ASLayoutableExtensibility.h in Headers */ = {isa = PBXBuildFile; fileRef = 698C8B601CAB49FC0052DC3F /* ASLayoutableExtensibility.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		698C8B621CAB49FC0052DC3F /* ASLayoutableExtensibility.h in Headers */ = {isa = PBXBuildFile; fileRef = 698C8B601CAB49FC0052DC3F /* ASLayoutableExtensibility.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		69E1006D1CA89CB600D88C1B /* ASEnvironmentInternal.h in Headers */ = {isa = PBXBuildFile; fileRef = 69E100691CA89CB600D88C1B /* ASEnvironmentInternal.h */; };
+		69E1006E1CA89CB600D88C1B /* ASEnvironmentInternal.h in Headers */ = {isa = PBXBuildFile; fileRef = 69E100691CA89CB600D88C1B /* ASEnvironmentInternal.h */; };
+		69E1006F1CA89CB600D88C1B /* ASEnvironmentInternal.mm in Sources */ = {isa = PBXBuildFile; fileRef = 69E1006A1CA89CB600D88C1B /* ASEnvironmentInternal.mm */; };
+		69E100701CA89CB600D88C1B /* ASEnvironmentInternal.mm in Sources */ = {isa = PBXBuildFile; fileRef = 69E1006A1CA89CB600D88C1B /* ASEnvironmentInternal.mm */; };
 		69F10C861C84C35D0026140C /* ASRangeControllerUpdateRangeProtocol+Beta.h in Headers */ = {isa = PBXBuildFile; fileRef = 69F10C851C84C35D0026140C /* ASRangeControllerUpdateRangeProtocol+Beta.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		69F10C871C84C35D0026140C /* ASRangeControllerUpdateRangeProtocol+Beta.h in Headers */ = {isa = PBXBuildFile; fileRef = 69F10C851C84C35D0026140C /* ASRangeControllerUpdateRangeProtocol+Beta.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		6BDC61F61979037800E50D21 /* AsyncDisplayKit.h in Headers */ = {isa = PBXBuildFile; fileRef = 6BDC61F51978FEA400E50D21 /* AsyncDisplayKit.h */; settings = {ATTRIBUTES = (Public, ); }; };
@@ -288,14 +298,6 @@
 		9C55866A1BD549CB00B50E3A /* ASAsciiArtBoxCreator.m in Sources */ = {isa = PBXBuildFile; fileRef = 9C5586681BD549CB00B50E3A /* ASAsciiArtBoxCreator.m */; };
 		9C55866B1BD54A1900B50E3A /* ASAsciiArtBoxCreator.m in Sources */ = {isa = PBXBuildFile; fileRef = 9C5586681BD549CB00B50E3A /* ASAsciiArtBoxCreator.m */; };
 		9C55866C1BD54A3000B50E3A /* ASAsciiArtBoxCreator.h in Headers */ = {isa = PBXBuildFile; fileRef = 9C5586671BD549CB00B50E3A /* ASAsciiArtBoxCreator.h */; settings = {ATTRIBUTES = (Public, ); }; };
-		9C5FA3511B8F6ADF00A62714 /* ASLayoutOptions.h in Headers */ = {isa = PBXBuildFile; fileRef = 9C5FA34F1B8F6ADF00A62714 /* ASLayoutOptions.h */; settings = {ATTRIBUTES = (Public, ); }; };
-		9C5FA3521B8F6ADF00A62714 /* ASLayoutOptions.h in Headers */ = {isa = PBXBuildFile; fileRef = 9C5FA34F1B8F6ADF00A62714 /* ASLayoutOptions.h */; settings = {ATTRIBUTES = (Public, ); }; };
-		9C5FA3531B8F6ADF00A62714 /* ASLayoutOptions.mm in Sources */ = {isa = PBXBuildFile; fileRef = 9C5FA3501B8F6ADF00A62714 /* ASLayoutOptions.mm */; };
-		9C5FA3541B8F6ADF00A62714 /* ASLayoutOptions.mm in Sources */ = {isa = PBXBuildFile; fileRef = 9C5FA3501B8F6ADF00A62714 /* ASLayoutOptions.mm */; };
-		9C5FA35F1B90C9A500A62714 /* ASLayoutOptionsPrivate.mm in Sources */ = {isa = PBXBuildFile; fileRef = 9C5FA35C1B90C9A500A62714 /* ASLayoutOptionsPrivate.mm */; };
-		9C5FA3601B90C9A500A62714 /* ASLayoutOptionsPrivate.mm in Sources */ = {isa = PBXBuildFile; fileRef = 9C5FA35C1B90C9A500A62714 /* ASLayoutOptionsPrivate.mm */; };
-		9C65A72A1BA8EA4D0084DA91 /* ASLayoutOptionsPrivate.h in Headers */ = {isa = PBXBuildFile; fileRef = 9C65A7291BA8EA4D0084DA91 /* ASLayoutOptionsPrivate.h */; };
-		9C65A72B1BA8EA4D0084DA91 /* ASLayoutOptionsPrivate.h in Headers */ = {isa = PBXBuildFile; fileRef = 9C65A7291BA8EA4D0084DA91 /* ASLayoutOptionsPrivate.h */; };
 		9C6BB3B21B8CC9C200F13F52 /* ASStaticLayoutable.h in Headers */ = {isa = PBXBuildFile; fileRef = 9C6BB3B01B8CC9C200F13F52 /* ASStaticLayoutable.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		9C6BB3B31B8CC9C200F13F52 /* ASStaticLayoutable.h in Headers */ = {isa = PBXBuildFile; fileRef = 9C6BB3B01B8CC9C200F13F52 /* ASStaticLayoutable.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		9C8221951BA237B80037F19A /* ASStackBaselinePositionedLayout.h in Headers */ = {isa = PBXBuildFile; fileRef = 9C8221931BA237B80037F19A /* ASStackBaselinePositionedLayout.h */; };
@@ -740,6 +742,11 @@
 		68B027791C1A79CC0041016B /* ASDisplayNode+Beta.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "ASDisplayNode+Beta.h"; sourceTree = "<group>"; };
 		68EE0DBB1C1B4ED300BA1B99 /* ASMainSerialQueue.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASMainSerialQueue.h; sourceTree = "<group>"; };
 		68EE0DBC1C1B4ED300BA1B99 /* ASMainSerialQueue.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASMainSerialQueue.mm; sourceTree = "<group>"; };
+		698548611CA9E025008A345F /* ASEnvironment.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASEnvironment.h; sourceTree = "<group>"; };
+		698548621CA9E025008A345F /* ASEnvironment.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ASEnvironment.m; sourceTree = "<group>"; };
+		698C8B601CAB49FC0052DC3F /* ASLayoutableExtensibility.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASLayoutableExtensibility.h; path = AsyncDisplayKit/Layout/ASLayoutableExtensibility.h; sourceTree = "<group>"; };
+		69E100691CA89CB600D88C1B /* ASEnvironmentInternal.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASEnvironmentInternal.h; sourceTree = "<group>"; };
+		69E1006A1CA89CB600D88C1B /* ASEnvironmentInternal.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASEnvironmentInternal.mm; sourceTree = "<group>"; };
 		69F10C851C84C35D0026140C /* ASRangeControllerUpdateRangeProtocol+Beta.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "ASRangeControllerUpdateRangeProtocol+Beta.h"; sourceTree = "<group>"; };
 		6BDC61F51978FEA400E50D21 /* AsyncDisplayKit.h */ = {isa = PBXFileReference; explicitFileType = sourcecode.c.h; path = AsyncDisplayKit.h; sourceTree = "<group>"; };
 		764D83D21C8EA515009B4FB8 /* AsyncDisplayKit+Debug.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "AsyncDisplayKit+Debug.h"; sourceTree = "<group>"; };
@@ -755,10 +762,6 @@
 		9C49C36E1B853957000B0DD5 /* ASStackLayoutable.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASStackLayoutable.h; path = AsyncDisplayKit/Layout/ASStackLayoutable.h; sourceTree = "<group>"; };
 		9C5586671BD549CB00B50E3A /* ASAsciiArtBoxCreator.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASAsciiArtBoxCreator.h; path = AsyncDisplayKit/Layout/ASAsciiArtBoxCreator.h; sourceTree = "<group>"; };
 		9C5586681BD549CB00B50E3A /* ASAsciiArtBoxCreator.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = ASAsciiArtBoxCreator.m; path = AsyncDisplayKit/Layout/ASAsciiArtBoxCreator.m; sourceTree = "<group>"; };
-		9C5FA34F1B8F6ADF00A62714 /* ASLayoutOptions.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASLayoutOptions.h; path = AsyncDisplayKit/Layout/ASLayoutOptions.h; sourceTree = "<group>"; };
-		9C5FA3501B8F6ADF00A62714 /* ASLayoutOptions.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; name = ASLayoutOptions.mm; path = AsyncDisplayKit/Layout/ASLayoutOptions.mm; sourceTree = "<group>"; };
-		9C5FA35C1B90C9A500A62714 /* ASLayoutOptionsPrivate.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; name = ASLayoutOptionsPrivate.mm; path = AsyncDisplayKit/Layout/ASLayoutOptionsPrivate.mm; sourceTree = "<group>"; };
-		9C65A7291BA8EA4D0084DA91 /* ASLayoutOptionsPrivate.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASLayoutOptionsPrivate.h; sourceTree = "<group>"; };
 		9C6BB3B01B8CC9C200F13F52 /* ASStaticLayoutable.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASStaticLayoutable.h; path = AsyncDisplayKit/Layout/ASStaticLayoutable.h; sourceTree = "<group>"; };
 		9C8221931BA237B80037F19A /* ASStackBaselinePositionedLayout.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASStackBaselinePositionedLayout.h; sourceTree = "<group>"; };
 		9C8221941BA237B80037F19A /* ASStackBaselinePositionedLayout.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASStackBaselinePositionedLayout.mm; sourceTree = "<group>"; };
@@ -802,7 +805,7 @@
 		ACF6ED161B17843500DA7C62 /* ASStackLayoutSpec.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASStackLayoutSpec.h; path = AsyncDisplayKit/Layout/ASStackLayoutSpec.h; sourceTree = "<group>"; };
 		ACF6ED171B17843500DA7C62 /* ASStackLayoutSpec.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; name = ASStackLayoutSpec.mm; path = AsyncDisplayKit/Layout/ASStackLayoutSpec.mm; sourceTree = "<group>"; };
 		ACF6ED181B17843500DA7C62 /* ASStaticLayoutSpec.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASStaticLayoutSpec.h; path = AsyncDisplayKit/Layout/ASStaticLayoutSpec.h; sourceTree = "<group>"; };
-		ACF6ED191B17843500DA7C62 /* ASStaticLayoutSpec.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; lineEnding = 0; name = ASStaticLayoutSpec.mm; path = AsyncDisplayKit/Layout/ASStaticLayoutSpec.mm; sourceTree = "<group>"; xcLanguageSpecificationIdentifier = xcode.lang.objcpp; };
+		ACF6ED191B17843500DA7C62 /* ASStaticLayoutSpec.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; lineEnding = 0; name = ASStaticLayoutSpec.mm; path = AsyncDisplayKit/Layout/ASStaticLayoutSpec.mm; sourceTree = "<group>"; };
 		ACF6ED431B17847A00DA7C62 /* ASInternalHelpers.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASInternalHelpers.h; sourceTree = "<group>"; };
 		ACF6ED441B17847A00DA7C62 /* ASInternalHelpers.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASInternalHelpers.mm; sourceTree = "<group>"; };
 		ACF6ED451B17847A00DA7C62 /* ASLayoutSpecUtilities.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASLayoutSpecUtilities.h; sourceTree = "<group>"; };
@@ -1116,14 +1119,6 @@
 		058D09E1195D050800B7D73C /* Details */ = {
 			isa = PBXGroup;
 			children = (
-				25B171EA1C12242700508A7A /* Data Controller */,
-				81EE384D1C8E94F000456208 /* ASRunLoopQueue.h */,
-				81EE384E1C8E94F000456208 /* ASRunLoopQueue.mm */,
-				CC7FD9DC1BB5E962005CCB2B /* ASPhotosFrameworkImageRequest.h */,
-				CC7FD9DD1BB5E962005CCB2B /* ASPhotosFrameworkImageRequest.m */,
-				251B8EF41BBB3D690087C538 /* ASCollectionViewFlowLayoutInspector.h */,
-				251B8EF51BBB3D690087C538 /* ASCollectionViewFlowLayoutInspector.m */,
-				251B8EF61BBB3D690087C538 /* ASDataController+Subclasses.h */,
 				058D09E2195D050800B7D73C /* _ASDisplayLayer.h */,
 				058D09E3195D050800B7D73C /* _ASDisplayLayer.mm */,
 				058D09E4195D050800B7D73C /* _ASDisplayView.h */,
@@ -1134,31 +1129,41 @@
 				054963481A1EA066000F8E56 /* ASBasicImageDownloader.mm */,
 				299DA1A71A828D2900162D41 /* ASBatchContext.h */,
 				299DA1A81A828D2900162D41 /* ASBatchContext.mm */,
+				251B8EF41BBB3D690087C538 /* ASCollectionViewFlowLayoutInspector.h */,
+				251B8EF51BBB3D690087C538 /* ASCollectionViewFlowLayoutInspector.m */,
 				205F0E1B1B373A2C007741D0 /* ASCollectionViewLayoutController.h */,
 				205F0E1C1B373A2C007741D0 /* ASCollectionViewLayoutController.mm */,
+				251B8EF61BBB3D690087C538 /* ASDataController+Subclasses.h */,
 				05A6D05819D0EB64002DD95E /* ASDealloc2MainObject.h */,
 				05A6D05919D0EB64002DD95E /* ASDealloc2MainObject.m */,
+				698548611CA9E025008A345F /* ASEnvironment.h */,
+				698548621CA9E025008A345F /* ASEnvironment.m */,
 				4640521B1A3F83C40061C0BA /* ASFlowLayoutController.h */,
 				4640521C1A3F83C40061C0BA /* ASFlowLayoutController.mm */,
 				058D09E6195D050800B7D73C /* ASHighlightOverlayLayer.h */,
 				058D09E7195D050800B7D73C /* ASHighlightOverlayLayer.mm */,
+				05F20AA31A15733C00DCA68A /* ASImageProtocols.h */,
 				430E7C8D1B4C23F100697A4C /* ASIndexPath.h */,
 				430E7C8E1B4C23F100697A4C /* ASIndexPath.m */,
-				05F20AA31A15733C00DCA68A /* ASImageProtocols.h */,
 				4640521D1A3F83C40061C0BA /* ASLayoutController.h */,
 				292C59991A956527007E5DD6 /* ASLayoutRangeType.h */,
 				68EE0DBB1C1B4ED300BA1B99 /* ASMainSerialQueue.h */,
 				68EE0DBC1C1B4ED300BA1B99 /* ASMainSerialQueue.mm */,
 				058D09E8195D050800B7D73C /* ASMutableAttributedStringBuilder.h */,
 				058D09E9195D050800B7D73C /* ASMutableAttributedStringBuilder.m */,
+				CC7FD9DC1BB5E962005CCB2B /* ASPhotosFrameworkImageRequest.h */,
+				CC7FD9DD1BB5E962005CCB2B /* ASPhotosFrameworkImageRequest.m */,
 				055F1A3619ABD413004DAFF1 /* ASRangeController.h */,
 				055F1A3719ABD413004DAFF1 /* ASRangeController.mm */,
 				69F10C851C84C35D0026140C /* ASRangeControllerUpdateRangeProtocol+Beta.h */,
+				81EE384D1C8E94F000456208 /* ASRunLoopQueue.h */,
+				81EE384E1C8E94F000456208 /* ASRunLoopQueue.mm */,
 				296A0A311A951715005ACEAA /* ASScrollDirection.h */,
 				205F0E111B371BD7007741D0 /* ASScrollDirection.m */,
 				058D0A12195D050800B7D73C /* ASThread.h */,
 				205F0E1F1B376416007741D0 /* CGRect+ASConvenience.h */,
 				205F0E201B376416007741D0 /* CGRect+ASConvenience.m */,
+				25B171EA1C12242700508A7A /* Data Controller */,
 				058D09F5195D050800B7D73C /* NSMutableAttributedString+TextKitAdditions.h */,
 				058D09F6195D050800B7D73C /* NSMutableAttributedString+TextKitAdditions.m */,
 				058D09F7195D050800B7D73C /* Transactions */,
@@ -1186,50 +1191,51 @@
 		058D0A01195D050800B7D73C /* Private */ = {
 			isa = PBXGroup;
 			children = (
-				DB55C25F1C6408D6004EDCF5 /* _ASTransitionContext.h */,
-				DB55C2601C6408D6004EDCF5 /* _ASTransitionContext.m */,
-				CC3B20811C3F76D600798563 /* ASPendingStateController.h */,
-				CC3B20821C3F76D600798563 /* ASPendingStateController.mm */,
-				CC3B20871C3F7A5400798563 /* ASWeakSet.h */,
-				CC3B20881C3F7A5400798563 /* ASWeakSet.m */,
-				AC026B6D1BD57DBF00BBC17E /* _ASHierarchyChangeSet.h */,
-				AC026B6E1BD57DBF00BBC17E /* _ASHierarchyChangeSet.m */,
-				9C65A7291BA8EA4D0084DA91 /* ASLayoutOptionsPrivate.h */,
-				9C8221931BA237B80037F19A /* ASStackBaselinePositionedLayout.h */,
-				9C8221941BA237B80037F19A /* ASStackBaselinePositionedLayout.mm */,
-				2967F9E11AB0A4CF0072E4AB /* ASBasicImageDownloaderInternal.h */,
 				058D0A02195D050800B7D73C /* _AS-objc-internal.h */,
 				058D0A03195D050800B7D73C /* _ASCoreAnimationExtras.h */,
 				058D0A04195D050800B7D73C /* _ASCoreAnimationExtras.mm */,
+				AC026B6D1BD57DBF00BBC17E /* _ASHierarchyChangeSet.h */,
+				AC026B6E1BD57DBF00BBC17E /* _ASHierarchyChangeSet.m */,
 				058D0A05195D050800B7D73C /* _ASPendingState.h */,
 				058D0A06195D050800B7D73C /* _ASPendingState.mm */,
 				058D0A07195D050800B7D73C /* _ASScopeTimer.h */,
-				058D0A08195D050800B7D73C /* ASDisplayNode+AsyncDisplay.mm */,
+				DB55C25F1C6408D6004EDCF5 /* _ASTransitionContext.h */,
+				DB55C2601C6408D6004EDCF5 /* _ASTransitionContext.m */,
+				2967F9E11AB0A4CF0072E4AB /* ASBasicImageDownloaderInternal.h */,
 				044285051BAA63FE00D16268 /* ASBatchFetching.h */,
 				044285061BAA63FE00D16268 /* ASBatchFetching.m */,
+				AEB7B0181C5962EA00662EF4 /* ASDefaultPlayButton.h */,
+				AEB7B0191C5962EA00662EF4 /* ASDefaultPlayButton.m */,
+				058D0A08195D050800B7D73C /* ASDisplayNode+AsyncDisplay.mm */,
 				058D0A09195D050800B7D73C /* ASDisplayNode+DebugTiming.h */,
 				058D0A0A195D050800B7D73C /* ASDisplayNode+DebugTiming.mm */,
-				058D0A0B195D050800B7D73C /* ASDisplayNode+UIViewBridge.mm */,
 				DE6EA3211C14000600183B10 /* ASDisplayNode+FrameworkPrivate.h */,
+				058D0A0B195D050800B7D73C /* ASDisplayNode+UIViewBridge.mm */,
+				058D0A0C195D050800B7D73C /* ASDisplayNodeInternal.h */,
 				E52405B41C8FEF16004DC8E7 /* ASDisplayNodeLayoutContext.h */,
 				E52405B21C8FEF03004DC8E7 /* ASDisplayNodeLayoutContext.mm */,
-				058D0A0C195D050800B7D73C /* ASDisplayNodeInternal.h */,
+				69E100691CA89CB600D88C1B /* ASEnvironmentInternal.h */,
+				69E1006A1CA89CB600D88C1B /* ASEnvironmentInternal.mm */,
 				058D0A0D195D050800B7D73C /* ASImageNode+CGExtras.h */,
 				058D0A0E195D050800B7D73C /* ASImageNode+CGExtras.m */,
-				058D0A10195D050800B7D73C /* ASSentinel.h */,
-				058D0A11195D050800B7D73C /* ASSentinel.m */,
 				ACF6ED431B17847A00DA7C62 /* ASInternalHelpers.h */,
 				ACF6ED441B17847A00DA7C62 /* ASInternalHelpers.mm */,
 				ACF6ED451B17847A00DA7C62 /* ASLayoutSpecUtilities.h */,
+				0442850B1BAA64EC00D16268 /* ASMultidimensionalArrayUtils.h */,
+				0442850C1BAA64EC00D16268 /* ASMultidimensionalArrayUtils.mm */,
+				CC3B20811C3F76D600798563 /* ASPendingStateController.h */,
+				CC3B20821C3F76D600798563 /* ASPendingStateController.mm */,
+				058D0A10195D050800B7D73C /* ASSentinel.h */,
+				058D0A11195D050800B7D73C /* ASSentinel.m */,
+				9C8221931BA237B80037F19A /* ASStackBaselinePositionedLayout.h */,
+				9C8221941BA237B80037F19A /* ASStackBaselinePositionedLayout.mm */,
 				ACF6ED461B17847A00DA7C62 /* ASStackLayoutSpecUtilities.h */,
 				ACF6ED471B17847A00DA7C62 /* ASStackPositionedLayout.h */,
 				ACF6ED481B17847A00DA7C62 /* ASStackPositionedLayout.mm */,
 				ACF6ED491B17847A00DA7C62 /* ASStackUnpositionedLayout.h */,
 				ACF6ED4A1B17847A00DA7C62 /* ASStackUnpositionedLayout.mm */,
-				0442850B1BAA64EC00D16268 /* ASMultidimensionalArrayUtils.h */,
+				CC3B20871C3F7A5400798563 /* ASWeakSet.h */,
-				0442850C1BAA64EC00D16268 /* ASMultidimensionalArrayUtils.mm */,
+				CC3B20881C3F7A5400798563 /* ASWeakSet.m */,
-				AEB7B0181C5962EA00662EF4 /* ASDefaultPlayButton.h */,
-				AEB7B0191C5962EA00662EF4 /* ASDefaultPlayButton.m */,
 				DBC452D91C5BF64600B16017 /* NSArray+Diffing.h */,
 				DBC452DA1C5BF64600B16017 /* NSArray+Diffing.m */,
 			);
@@ -1314,14 +1320,13 @@
 				ACF6ED041B17843500DA7C62 /* ASCenterLayoutSpec.mm */,
 				ACF6ED071B17843500DA7C62 /* ASDimension.h */,
 				ACF6ED081B17843500DA7C62 /* ASDimension.mm */,
-				AC47D9431B3BB41900AAEE9D /* ASRelativeSize.h */,
-				AC47D9441B3BB41900AAEE9D /* ASRelativeSize.mm */,
 				ACF6ED091B17843500DA7C62 /* ASInsetLayoutSpec.h */,
 				ACF6ED0A1B17843500DA7C62 /* ASInsetLayoutSpec.mm */,
 				ACF6ED0B1B17843500DA7C62 /* ASLayout.h */,
 				ACF6ED0C1B17843500DA7C62 /* ASLayout.mm */,
 				ACF6ED111B17843500DA7C62 /* ASLayoutable.h */,
 				E55D86311CA8A14000A0C26F /* ASLayoutable.mm */,
+				698C8B601CAB49FC0052DC3F /* ASLayoutableExtensibility.h */,
 				9CDC18CB1B910E12004965E2 /* ASLayoutablePrivate.h */,
 				ACF6ED0D1B17843500DA7C62 /* ASLayoutSpec.h */,
 				ACF6ED0E1B17843500DA7C62 /* ASLayoutSpec.mm */,
@@ -1331,6 +1336,8 @@
 				ACF6ED151B17843500DA7C62 /* ASRatioLayoutSpec.mm */,
 				7A06A7391C35F08800FE8DAA /* ASRelativeLayoutSpec.h */,
 				7A06A7381C35F08800FE8DAA /* ASRelativeLayoutSpec.mm */,
+				AC47D9431B3BB41900AAEE9D /* ASRelativeSize.h */,
+				AC47D9441B3BB41900AAEE9D /* ASRelativeSize.mm */,
 				9C49C36E1B853957000B0DD5 /* ASStackLayoutable.h */,
 				AC21EC0F1B3D0BF600C8B19A /* ASStackLayoutDefines.h */,
 				ACF6ED161B17843500DA7C62 /* ASStackLayoutSpec.h */,
@@ -1338,9 +1345,6 @@
 				9C6BB3B01B8CC9C200F13F52 /* ASStaticLayoutable.h */,
 				ACF6ED181B17843500DA7C62 /* ASStaticLayoutSpec.h */,
 				ACF6ED191B17843500DA7C62 /* ASStaticLayoutSpec.mm */,
-				9C5FA34F1B8F6ADF00A62714 /* ASLayoutOptions.h */,
-				9C5FA3501B8F6ADF00A62714 /* ASLayoutOptions.mm */,
-				9C5FA35C1B90C9A500A62714 /* ASLayoutOptionsPrivate.mm */,
 			);
 			name = Layout;
 			path = ..;
@@ -1379,6 +1383,8 @@
 			isa = PBXHeadersBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				698C8B611CAB49FC0052DC3F /* ASLayoutableExtensibility.h in Headers */,
+				698548631CA9E025008A345F /* ASEnvironment.h in Headers */,
 				E5711A2B1C840C81009619D4 /* ASIndexedNodeContext.h in Headers */,
 				257754C21BEE458E00737CA5 /* ASTextKitCoreTextAdditions.h in Headers */,
 				A373200F1C571B730011FC94 /* ASTextNode+Beta.h in Headers */,
@@ -1462,8 +1468,6 @@
 				9CDC18CC1B910E12004965E2 /* ASLayoutablePrivate.h in Headers */,
 				B0F8805A1BEAEC7500D17647 /* ASTableNode.h in Headers */,
 				464052241A3F83C40061C0BA /* ASLayoutController.h in Headers */,
-				9C5FA3511B8F6ADF00A62714 /* ASLayoutOptions.h in Headers */,
-				9C65A72A1BA8EA4D0084DA91 /* ASLayoutOptionsPrivate.h in Headers */,
 				292C599F1A956527007E5DD6 /* ASLayoutRangeType.h in Headers */,
 				257754B61BEE44CD00737CA5 /* ASEqualityHashHelpers.h in Headers */,
 				ACF6ED261B17843500DA7C62 /* ASLayoutSpec.h in Headers */,
@@ -1487,6 +1491,7 @@
 				9C8221951BA237B80037F19A /* ASStackBaselinePositionedLayout.h in Headers */,
 				257754C31BEE458E00737CA5 /* ASTextNodeTypes.h in Headers */,
 				9C49C36F1B853957000B0DD5 /* ASStackLayoutable.h in Headers */,
+				69E1006D1CA89CB600D88C1B /* ASEnvironmentInternal.h in Headers */,
 				AC21EC101B3D0BF600C8B19A /* ASStackLayoutDefines.h in Headers */,
 				CC7FD9DE1BB5E962005CCB2B /* ASPhotosFrameworkImageRequest.h in Headers */,
 				ACF6ED2F1B17843500DA7C62 /* ASStackLayoutSpec.h in Headers */,
@@ -1522,6 +1527,8 @@
 			isa = PBXHeadersBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				698C8B621CAB49FC0052DC3F /* ASLayoutableExtensibility.h in Headers */,
+				698548641CA9E025008A345F /* ASEnvironment.h in Headers */,
 				AC026B6A1BD57D6F00BBC17E /* ASChangeSetDataController.h in Headers */,
 				B35062481B010EFD0018CF92 /* _AS-objc-internal.h in Headers */,
 				69F10C871C84C35D0026140C /* ASRangeControllerUpdateRangeProtocol+Beta.h in Headers */,
@@ -1598,8 +1605,6 @@
 				34EFC7691B701CE100AD841F /* ASLayoutable.h in Headers */,
 				9CDC18CD1B910E12004965E2 /* ASLayoutablePrivate.h in Headers */,
 				B35062201B010EFD0018CF92 /* ASLayoutController.h in Headers */,
-				9C5FA3521B8F6ADF00A62714 /* ASLayoutOptions.h in Headers */,
-				9C65A72B1BA8EA4D0084DA91 /* ASLayoutOptionsPrivate.h in Headers */,
 				B35062211B010EFD0018CF92 /* ASLayoutRangeType.h in Headers */,
 				34EFC76A1B701CE600AD841F /* ASLayoutSpec.h in Headers */,
 				34EFC7791B701D3600AD841F /* ASLayoutSpecUtilities.h in Headers */,
@@ -1640,6 +1645,7 @@
 				92DD2FE81BF4D0A80074C9DD /* ASMapNode.h in Headers */,
 				044284FE1BAA387800D16268 /* ASStackLayoutSpecUtilities.h in Headers */,
 				34EFC7751B701D2400AD841F /* ASStackPositionedLayout.h in Headers */,
+				69E1006E1CA89CB600D88C1B /* ASEnvironmentInternal.h in Headers */,
 				34EFC7771B701D2D00AD841F /* ASStackUnpositionedLayout.h in Headers */,
 				9C6BB3B31B8CC9C200F13F52 /* ASStaticLayoutable.h in Headers */,
 				34EFC7731B701D0700AD841F /* ASStaticLayoutSpec.h in Headers */,
@@ -1873,6 +1879,7 @@
 				DBDB83961C6E879900D0098C /* ASPagerFlowLayout.m in Sources */,
 				058D0A26195D050800B7D73C /* _ASCoreAnimationExtras.mm in Sources */,
 				257754B41BEE44CD00737CA5 /* ASTextKitTailTruncater.mm in Sources */,
+				69E1006F1CA89CB600D88C1B /* ASEnvironmentInternal.mm in Sources */,
 				AC026B711BD57DBF00BBC17E /* _ASHierarchyChangeSet.m in Sources */,
 				257754BF1BEE458E00737CA5 /* ASTextKitCoreTextAdditions.m in Sources */,
 				058D0A18195D050800B7D73C /* _ASDisplayLayer.mm in Sources */,
@@ -1916,10 +1923,9 @@
 				430E7C911B4C23F100697A4C /* ASIndexPath.m in Sources */,
 				ACF6ED231B17843500DA7C62 /* ASInsetLayoutSpec.mm in Sources */,
 				ACF6ED4C1B17847A00DA7C62 /* ASInternalHelpers.mm in Sources */,
+				698548651CA9E025008A345F /* ASEnvironment.m in Sources */,
 				ACF6ED251B17843500DA7C62 /* ASLayout.mm in Sources */,
 				DB55C2631C6408D6004EDCF5 /* _ASTransitionContext.m in Sources */,
-				9C5FA3531B8F6ADF00A62714 /* ASLayoutOptions.mm in Sources */,
-				9C5FA35F1B90C9A500A62714 /* ASLayoutOptionsPrivate.mm in Sources */,
 				251B8EFA1BBB3D690087C538 /* ASCollectionViewFlowLayoutInspector.m in Sources */,
 				ACF6ED271B17843500DA7C62 /* ASLayoutSpec.mm in Sources */,
 				257754B01BEE44CD00737CA5 /* ASTextKitRenderer+TextChecking.mm in Sources */,
@@ -2027,6 +2033,7 @@
 				B35062421B010EFD0018CF92 /* _ASAsyncTransactionGroup.m in Sources */,
 				B350624A1B010EFD0018CF92 /* _ASCoreAnimationExtras.mm in Sources */,
 				68EE0DC01C1B4ED300BA1B99 /* ASMainSerialQueue.mm in Sources */,
+				698548661CA9E025008A345F /* ASEnvironment.m in Sources */,
 				2767E9421BB19BD600EA9B77 /* ASViewController.m in Sources */,
 				B35062101B010EFD0018CF92 /* _ASDisplayLayer.mm in Sources */,
 				9C55866B1BD54A1900B50E3A /* ASAsciiArtBoxCreator.m in Sources */,
@@ -2056,6 +2063,7 @@
 				636EA1A41C7FF4EC00EE152F /* NSArray+Diffing.m in Sources */,
 				B35062501B010EFD0018CF92 /* ASDisplayNode+DebugTiming.mm in Sources */,
 				DEC146B91C37A16A004A0EE7 /* ASCollectionInternal.m in Sources */,
+				69E100701CA89CB600D88C1B /* ASEnvironmentInternal.mm in Sources */,
 				254C6B891BF94F8A003EC431 /* ASTextKitRenderer+Positioning.mm in Sources */,
 				E5711A301C840C96009619D4 /* ASIndexedNodeContext.m in Sources */,
 				B35062511B010EFD0018CF92 /* ASDisplayNode+UIViewBridge.mm in Sources */,
@@ -2073,8 +2081,6 @@
 				34EFC7601B701C8B00AD841F /* ASInsetLayoutSpec.mm in Sources */,
 				34EFC75E1B701BF000AD841F /* ASInternalHelpers.mm in Sources */,
 				34EFC7681B701CDE00AD841F /* ASLayout.mm in Sources */,
-				9C5FA3541B8F6ADF00A62714 /* ASLayoutOptions.mm in Sources */,
-				9C5FA3601B90C9A500A62714 /* ASLayoutOptionsPrivate.mm in Sources */,
 				DECBD6EA1BE56E1900CF4905 /* ASButtonNode.mm in Sources */,
 				254C6B841BF94F8A003EC431 /* ASTextNodeWordKerner.m in Sources */,
 				34EFC76B1B701CEB00AD841F /* ASLayoutSpec.mm in Sources */,

AsyncDisplayKit/ASDisplayNode.mm

@@ -10,7 +10,6 @@
 #import "ASDisplayNode+Subclasses.h"
 #import "ASDisplayNode+FrameworkPrivate.h"
 #import "ASDisplayNode+Beta.h"
-#import "ASLayoutOptionsPrivate.h"
 
 #import <objc/runtime.h>
 #import <deque>
@@ -25,6 +24,7 @@
 #import "ASDisplayNodeExtras.h"
 #import "ASEqualityHelpers.h"
 #import "ASRunLoopQueue.h"
+#import "ASEnvironmentInternal.h"
 
 #import "ASInternalHelpers.h"
 #import "ASLayout.h"
@@ -60,7 +60,7 @@ NSString * const ASRenderingEngineDidDisplayNodesScheduledBeforeTimestamp = @"AS
 @implementation ASDisplayNode
 
 // these dynamic properties all defined in ASLayoutOptionsPrivate.m
-@dynamic spacingAfter, spacingBefore, flexGrow, flexShrink, flexBasis, alignSelf, ascender, descender, sizeRange, layoutPosition, layoutOptions;
+@dynamic spacingAfter, spacingBefore, flexGrow, flexShrink, flexBasis, alignSelf, ascender, descender, sizeRange, layoutPosition;
 @synthesize name = _name;
 @synthesize preferredFrameSize = _preferredFrameSize;
 @synthesize isFinalLayoutable = _isFinalLayoutable;
@@ -252,6 +252,8 @@ static ASDisplayNodeMethodOverrides GetASDisplayNodeMethodOverrides(Class c)
   _contentsScaleForDisplay = ASScreenScale();
   _displaySentinel = [[ASSentinel alloc] init];
   _preferredFrameSize = CGSizeZero;
+  
+  _environmentState = ASEnvironmentStateMakeDefault();
 }
 
 - (id)init
@@ -1700,6 +1702,10 @@ static NSInteger incrementIfFound(NSInteger i) {
       [self exitHierarchyState:stateToEnterOrExit];
     }
   }
+    
+  if ([newSupernode supportsUpwardPropagation]) {
+    ASEnvironmentStatePropagateUp(newSupernode, _environmentState.layoutOptionsState);
+  }
 }
 
 // Track that a node will be displayed as part of the current node hierarchy.
@@ -1854,6 +1860,7 @@ void recursivelyTriggerDisplayForLayer(CALayer *layer, BOOL shouldBlock)
   ASDN::MutexLocker l(_propertyLock);
   if (_methodOverrides & ASDisplayNodeMethodOverrideLayoutSpecThatFits) {
     ASLayoutSpec *layoutSpec = [self layoutSpecThatFits:constrainedSize];
+    layoutSpec.parent = self;
     layoutSpec.isMutable = NO;
     ASLayout *layout = [layoutSpec measureWithSizeRange:constrainedSize];
     // Make sure layoutableObject of the root layout is `self`, so that the flattened layout will be structurally correct.
@@ -1918,6 +1925,7 @@ void recursivelyTriggerDisplayForLayer(CALayer *layer, BOOL shouldBlock)
   ASDN::MutexLocker l(_propertyLock);
   if (! CGSizeEqualToSize(_preferredFrameSize, preferredFrameSize)) {
     _preferredFrameSize = preferredFrameSize;
+    self.sizeRange = ASRelativeSizeRangeMake(ASRelativeSizeMakeWithCGSize(_preferredFrameSize), ASRelativeSizeMakeWithCGSize(_preferredFrameSize));
     [self invalidateCalculatedLayout];
   }
 }
@@ -2666,6 +2674,37 @@ static const char *ASDisplayNodeDrawingPriorityKey = "ASDrawingPriority";
   return self;
 }
 
+#pragma mark - ASEnvironment
+
+- (ASEnvironmentState)environmentState
+{
+  return _environmentState;
+}
+
+- (void)setEnvironmentState:(ASEnvironmentState)environmentState
+{
+  _environmentState = environmentState;
+}
+
+- (ASDisplayNode *)parent
+{
+  return self.supernode;
+}
+
+- (NSArray<ASDisplayNode *> *)children
+{
+  return self.subnodes;
+}
+
+- (BOOL)supportsUpwardPropagation
+{
+  return YES;
+}
+
+ASEnvironmentLayoutOptionsForwarding
+ASEnvironmentLayoutExtensibilityForwarding
+
+
 #if TARGET_OS_TV
 #pragma mark - UIFocusEnvironment Protocol (tvOS)
 

AsyncDisplayKit/ASTextNode.mm

@@ -365,6 +365,12 @@ static NSArray *DefaultLinkAttributeNames = @[ NSLinkAttributeName ];
 
   _attributedString = ASCleanseAttributedStringOfCoreTextAttributes(attributedString);
     
+  if (_attributedString.length > 0) {
+    CGFloat screenScale = ASScreenScale();
+    self.ascender = round([[_attributedString attribute:NSFontAttributeName atIndex:0 effectiveRange:NULL] ascender] * screenScale)/screenScale;
+    self.descender = round([[_attributedString attribute:NSFontAttributeName atIndex:_attributedString.length - 1 effectiveRange:NULL] descender] * screenScale)/screenScale;
+  }
+
   // Sync the truncation string with attributes from the updated _attributedString
   // Without this, the size calculation of the text with truncation applied will
   // not take into account the attributes of attributedString in the last line

AsyncDisplayKit/AsyncDisplayKit.h

@@ -40,6 +40,7 @@
 
 #import <AsyncDisplayKit/ASLayout.h>
 #import <AsyncDisplayKit/ASDimension.h>
+#import <AsyncDisplayKit/ASEnvironment.h>
 #import <AsyncDisplayKit/ASLayoutable.h>
 #import <AsyncDisplayKit/ASLayoutSpec.h>
 #import <AsyncDisplayKit/ASBackgroundLayoutSpec.h>
@@ -67,7 +68,6 @@
 #import <AsyncDisplayKit/ASEqualityHelpers.h>
 #import <AsyncDisplayKit/ASHighlightOverlayLayer.h>
 #import <AsyncDisplayKit/ASIndexPath.h>
-#import <AsyncDisplayKit/ASLayoutOptions.h>
 #import <AsyncDisplayKit/ASLog.h>
 #import <AsyncDisplayKit/ASMutableAttributedStringBuilder.h>
 #import <AsyncDisplayKit/ASThread.h>

AsyncDisplayKit/Details/ASEnvironment.h

@@ -0,0 +1,98 @@
+/*
+ *  Copyright (c) 2014-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
+#import <Foundation/Foundation.h>
+
+#import "ASDimension.h"
+#import "ASStackLayoutDefines.h"
+#import "ASRelativeSize.h"
+
+
+ASDISPLAYNODE_EXTERN_C_BEGIN
+NS_ASSUME_NONNULL_BEGIN
+
+static const int kMaxEnvironmentStateBoolExtensions = 1;
+static const int kMaxEnvironmentStateIntegerExtensions = 4;
+static const int kMaxEnvironmentStateEdgeInsetExtensions = 1;
+
+#pragma mark -
+
+typedef struct ASEnvironmentStateExtensions {
+  // Values to store extensions
+  BOOL boolExtensions[kMaxEnvironmentStateBoolExtensions];
+  NSInteger integerExtensions[kMaxEnvironmentStateIntegerExtensions];
+  UIEdgeInsets edgeInsetsExtensions[kMaxEnvironmentStateEdgeInsetExtensions];
+} ASEnvironmentStateExtensions;
+
+#pragma mark - ASEnvironmentLayoutOptionsState
+
+typedef struct ASEnvironmentLayoutOptionsState {
+  CGFloat spacingBefore;// = 0;
+  CGFloat spacingAfter;// = 0;
+  BOOL flexGrow;// = NO;
+  BOOL flexShrink;// = NO;
+  ASRelativeDimension flexBasis;// = ASRelativeDimensionUnconstrained;
+  ASStackLayoutAlignSelf alignSelf;// = ASStackLayoutAlignSelfAuto;
+  CGFloat ascender;// = 0;
+  CGFloat descender;// = 0;
+  
+  ASRelativeSizeRange sizeRange;// = ASRelativeSizeRangeMake(ASRelativeSizeMakeWithCGSize(CGSizeZero), ASRelativeSizeMakeWithCGSize(CGSizeZero));;
+  CGPoint layoutPosition;// = CGPointZero;
+  
+  ASEnvironmentStateExtensions _extensions;
+} ASEnvironmentLayoutOptionsState;
+
+
+#pragma mark - ASEnvironmentHierarchyState
+
+typedef struct ASEnvironmentHierarchyState {
+  unsigned rasterized:1; // = NO
+  unsigned rangeManaged:1; // = NO
+  unsigned transitioningSupernodes:1; // = NO
+  unsigned layoutPending:1; // = NO
+} ASEnvironmentHierarchyState;
+
+
+#pragma mark - ASEnvironmentState
+
+typedef struct ASEnvironmentState {
+  struct ASEnvironmentHierarchyState hierarchyState;
+  struct ASEnvironmentLayoutOptionsState layoutOptionsState;
+} ASEnvironmentState;
+extern ASEnvironmentState ASEnvironmentStateMakeDefault();
+
+ASDISPLAYNODE_EXTERN_C_END
+
+
+#pragma mark - ASEnvironment
+
+/**
+ * ASEnvironment allows objects that conform to the ASEnvironment protocol to be able to propagate specific States
+ * defined in an ASEnvironmentState up and down the ASEnvironment tree. To be able to define how merges of
+ * States should happen, specific merge functions can be provided
+ */
+@protocol ASEnvironment <NSObject>
+
+/// The environment collection of an object which class conforms to the ASEnvironment protocol
+- (ASEnvironmentState)environmentState;
+- (void)setEnvironmentState:(ASEnvironmentState)environmentState;
+
+/// Returns the parent of an object which class conforms to the ASEnvironment protocol
+- (id<ASEnvironment> _Nullable)parent;
+
+/// Returns all children of an object which class conforms to the ASEnvironment protocol
+- (NSArray<id<ASEnvironment>> *)children;
+
+/// Classes should implement this method and return YES / NO dependent if upward propagation is enabled or not 
+- (BOOL)supportsUpwardPropagation;
+
+@end
+
+NS_ASSUME_NONNULL_END

AsyncDisplayKit/Details/ASEnvironment.m

@@ -0,0 +1,33 @@
+/*
+ *  Copyright (c) 2014-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
+#import "ASEnvironment.h"
+
+ASEnvironmentLayoutOptionsState _ASEnvironmentLayoutOptionsStateMakeDefault()
+{
+  return (ASEnvironmentLayoutOptionsState) {
+    // Default values can be defined in here
+  };
+}
+
+ASEnvironmentHierarchyState _ASEnvironmentHierarchyStateMakeDefault()
+{
+  return (ASEnvironmentHierarchyState) {
+    // Default values can be defined in here
+  };
+}
+
+ASEnvironmentState ASEnvironmentStateMakeDefault()
+{
+  return (ASEnvironmentState) {
+    .layoutOptionsState = _ASEnvironmentLayoutOptionsStateMakeDefault(),
+    .hierarchyState = _ASEnvironmentHierarchyStateMakeDefault()
+  };
+}

AsyncDisplayKit/Layout/ASLayoutOptions.h

@@ -1,91 +0,0 @@
-/*
- *  Copyright (c) 2014-present, Facebook, Inc.
- *  All rights reserved.
- *
- *  This source code is licensed under the BSD-style license found in the
- *  LICENSE file in the root directory of this source tree. An additional grant
- *  of patent rights can be found in the PATENTS file in the same directory.
- *
- */
-
-#import <Foundation/Foundation.h>
-#import <AsyncDisplayKit/ASStaticLayoutable.h>
-#import <AsyncDisplayKit/ASStackLayoutable.h>
-
-NS_ASSUME_NONNULL_BEGIN
-
-@protocol ASLayoutable;
-
-/**
- *  A store for all of the options defined by ASLayoutSpec subclasses. All implementors of ASLayoutable own a
- *  ASLayoutOptions. When certain layoutSpecs need option values, they are read from this class.
- *
- *  Unless you wish to create a custom layout spec, ASLayoutOptions can largely be ignored. Instead you can access
- *  the layout option properties exposed in ASLayoutable directly, which will set the values in ASLayoutOptions
- *  behind the scenes.
- */
-@interface ASLayoutOptions : NSObject <ASStackLayoutable, ASStaticLayoutable, NSCopying>
-
-/**
- *  Sets the class name for the ASLayoutOptions subclasses that will be created when a node or layoutSpec's options 
- *  are first accessed.
- *
- *  If you create a custom layoutSpec that includes new options, you will want to subclass ASLayoutOptions to add
- *  the new layout options for your layoutSpec(s). In order to make sure your subclass is created instead of an 
- *  instance of ASLayoutOptions, call setDefaultLayoutOptionsClass: early in app launch (applicationDidFinishLaunching:)
- *  with your subclass's class.
- *
- *  @param defaultLayoutOptionsClass The class of ASLayoutOptions that will be lazily created for a node or layout spec.
- */
-+ (void)setDefaultLayoutOptionsClass:(Class)defaultLayoutOptionsClass;
-
-/**
- *  @return the Class of ASLayoutOptions that will be created for a node or layoutspec. Defaults to [ASLayoutOptions class];
- */
-+ (Class)defaultLayoutOptionsClass;
-
-#pragma mark - Subclasses should implement these!
-/**
- *  Initializes a new ASLayoutOptions using the given layoutable to assign any intrinsic option values.
- *  This init function sets a sensible default value for each layout option. If you create a subclass of 
- *  ASLayoutOptions, your subclass should do the same.
- *
- *  @param layoutable The layoutable that will own these options. The layoutable will be used to set any intrinsic
- *         layoutOptions. For example, if the layoutable is an ASTextNode the ascender/descender values will get set.
- *
- *  @return a new instance of ASLayoutOptions
- */
-- (instancetype)initWithLayoutable:(id<ASLayoutable>)layoutable;
-
-/**
- *  Copies the values of layoutOptions into self. This is useful when placing a layoutable inside of another. Consider
- *  an ASTextNode that you want to align to the baseline by putting it in an ASStackLayoutSpec. Before that, you want
- *  to inset the ASTextNode by placing it in an ASInsetLayoutSpec. An ASInsetLayoutSpec will not have any information
- *  about the ASTextNode's ascender/descender unless we copy over the layout options from ASTextNode to ASInsetLayoutSpec.
- *  This is done automatically and should not need to be called directly. It is listed here to make sure that any 
- *  ASLayoutOptions subclass implements the method.
- *
- *  @param layoutOptions The layoutOptions to copy from
- */
-- (void)copyFromOptions:(ASLayoutOptions *)layoutOptions;
-
-#pragma mark - ASStackLayoutable
-
-@property (nonatomic, readwrite) CGFloat spacingBefore;
-@property (nonatomic, readwrite) CGFloat spacingAfter;
-@property (nonatomic, readwrite) BOOL flexGrow;
-@property (nonatomic, readwrite) BOOL flexShrink;
-@property (nonatomic, readwrite) ASRelativeDimension flexBasis;
-@property (nonatomic, readwrite) ASStackLayoutAlignSelf alignSelf;
-@property (nonatomic, readwrite) CGFloat ascender;
-@property (nonatomic, readwrite) CGFloat descender;
-
-#pragma mark - ASStaticLayoutable
-
-@property (nonatomic, readwrite) ASRelativeSizeRange sizeRange;
-@property (nonatomic, readwrite) CGPoint layoutPosition;
-
-@end
-
-NS_ASSUME_NONNULL_END
-

AsyncDisplayKit/Layout/ASLayoutOptions.mm

@@ -1,263 +0,0 @@
-/*
- *  Copyright (c) 2014-present, Facebook, Inc.
- *  All rights reserved.
- *
- *  This source code is licensed under the BSD-style license found in the
- *  LICENSE file in the root directory of this source tree. An additional grant
- *  of patent rights can be found in the PATENTS file in the same directory.
- *
- */
-
-#import "ASLayoutOptions.h"
-
-#import <AsyncDisplayKit/ASAssert.h>
-#import <AsyncDisplayKit/ASThread.h>
-#import <AsyncDisplayKit/ASTextNode.h>
-#import "ASInternalHelpers.h"
-
-@interface ASLayoutOptions()
-{
-  ASDN::RecursiveMutex _propertyLock;
-}
-@end
-
-@implementation ASLayoutOptions
-
-@synthesize spacingBefore = _spacingBefore;
-@synthesize spacingAfter = _spacingAfter;
-@synthesize flexGrow = _flexGrow;
-@synthesize flexShrink = _flexShrink;
-@synthesize flexBasis = _flexBasis;
-@synthesize alignSelf = _alignSelf;
-
-@synthesize ascender = _ascender;
-@synthesize descender = _descender;
-
-@synthesize sizeRange = _sizeRange;
-@synthesize layoutPosition = _layoutPosition;
-
-static Class gDefaultLayoutOptionsClass = nil;
-+ (void)setDefaultLayoutOptionsClass:(Class)defaultLayoutOptionsClass
-{
-  gDefaultLayoutOptionsClass = defaultLayoutOptionsClass;
-}
-
-+ (Class)defaultLayoutOptionsClass
-{
-  static dispatch_once_t onceToken;
-  dispatch_once(&onceToken, ^{
-    if (gDefaultLayoutOptionsClass == nil) {
-      // If someone is asking for this and it hasn't been customized yet, use the default.
-      gDefaultLayoutOptionsClass = [ASLayoutOptions class];
-    }
-  });
-  return gDefaultLayoutOptionsClass;
-}
-
-- (instancetype)init
-{
-  return nil;
-}
-
-- (instancetype)initWithLayoutable:(id<ASLayoutable>)layoutable
-{
-  self = [super init];
-  if (self) {
-    
-    self.flexBasis = ASRelativeDimensionUnconstrained;
-    self.sizeRange = ASRelativeSizeRangeMake(ASRelativeSizeMakeWithCGSize(CGSizeZero), ASRelativeSizeMakeWithCGSize(CGSizeZero));
-    self.layoutPosition = CGPointZero;
-    
-    // The following properties use a default value of 0 which we do not need to assign.
-    // self.spacingBefore = 0;
-    // self.spacingAfter = 0;
-    // self.flexGrow = NO;
-    // self.flexShrink = NO;
-    // self.alignSelf = ASStackLayoutAlignSelfAuto;
-    // self.ascender = 0;
-    // self.descender = 0;
-    
-    [self setValuesFromLayoutable:layoutable];
-  }
-  return self;
-}
-
-#pragma mark - NSCopying
-- (id)copyWithZone:(NSZone *)zone
-{
-  ASLayoutOptions *copy = [[[self class] alloc] init];
-  [copy copyFromOptions:self];
-  return copy;
-}
-
-- (void)copyFromOptions:(ASLayoutOptions *)layoutOptions
-{
-  ASDN::MutexLocker l(_propertyLock);
-  self.flexBasis = layoutOptions.flexBasis;
-  self.spacingAfter = layoutOptions.spacingAfter;
-  self.spacingBefore = layoutOptions.spacingBefore;
-  self.flexGrow = layoutOptions.flexGrow;
-  self.flexShrink = layoutOptions.flexShrink;
-  self.alignSelf = layoutOptions.alignSelf;
-  
-  self.ascender = layoutOptions.ascender;
-  self.descender = layoutOptions.descender;
-  
-  self.sizeRange = layoutOptions.sizeRange;
-  self.layoutPosition = layoutOptions.layoutPosition;
-}
-
-/**
- *  Given an id<ASLayoutable>, set up layout options that are intrinsically defined by the layoutable.
- *
- *  While this could be done in the layoutable object itself, moving the logic into the ASLayoutOptions class 
- *  allows a custom spec to set up defaults without needing to alter the layoutable itself. For example,
- *  image you were creating a custom baseline spec that needed ascender/descender. To assign values automatically
- *  when a text node's attribute string is set, you would need to subclass ASTextNode and assign the values in the
- *  override of setAttributeString. However, assigning the defaults in an ASLayoutOptions subclass's
- *  setValuesFromLayoutable allows you to create a custom spec without the need to create a
- *  subclass of ASTextNode.
- *
- *  @param layoutable The layoutable object to inspect for default intrinsic layout option values
- */
-- (void)setValuesFromLayoutable:(id<ASLayoutable>)layoutable
-{
-  ASDN::MutexLocker l(_propertyLock);
-  if ([layoutable isKindOfClass:[ASDisplayNode class]]) {
-    ASDisplayNode *displayNode = (ASDisplayNode *)layoutable;
-    self.sizeRange = ASRelativeSizeRangeMake(ASRelativeSizeMakeWithCGSize(displayNode.preferredFrameSize), ASRelativeSizeMakeWithCGSize(displayNode.preferredFrameSize));
-    
-    if ([layoutable isKindOfClass:[ASTextNode class]]) {
-      ASTextNode *textNode = (ASTextNode *)layoutable;
-      NSAttributedString *attributedString = textNode.attributedString;
-      if (attributedString.length > 0) {
-        CGFloat screenScale = ASScreenScale();
-        self.ascender = round([[attributedString attribute:NSFontAttributeName atIndex:0 effectiveRange:NULL] ascender] * screenScale)/screenScale;
-        self.descender = round([[attributedString attribute:NSFontAttributeName atIndex:attributedString.length - 1 effectiveRange:NULL] descender] * screenScale)/screenScale;
-      }
-    }
-    
-  }
-}
-
-- (CGFloat)spacingAfter
-{
-  ASDN::MutexLocker l(_propertyLock);
-  return _spacingAfter;
-}
-
-- (void)setSpacingAfter:(CGFloat)spacingAfter
-{
-  ASDN::MutexLocker l(_propertyLock);
-  _spacingAfter = spacingAfter;
-}
-
-- (CGFloat)spacingBefore
-{
-  ASDN::MutexLocker l(_propertyLock);
-  return _spacingBefore;
-}
-
-- (void)setSpacingBefore:(CGFloat)spacingBefore
-{
-  ASDN::MutexLocker l(_propertyLock);
-  _spacingBefore = spacingBefore;
-}
-
-- (BOOL)flexGrow
-{
-  ASDN::MutexLocker l(_propertyLock);
-  return _flexGrow;
-}
-
-- (void)setFlexGrow:(BOOL)flexGrow
-{
-  ASDN::MutexLocker l(_propertyLock);
-  _flexGrow = flexGrow;
-}
-
-- (BOOL)flexShrink
-{
-  ASDN::MutexLocker l(_propertyLock);
-  return _flexShrink;
-}
-
-- (void)setFlexShrink:(BOOL)flexShrink
-{
-  ASDN::MutexLocker l(_propertyLock);
-  _flexShrink = flexShrink;
-}
-
-- (ASRelativeDimension)flexBasis
-{
-  ASDN::MutexLocker l(_propertyLock);
-  return _flexBasis;
-}
-
-- (void)setFlexBasis:(ASRelativeDimension)flexBasis
-{
-  ASDN::MutexLocker l(_propertyLock);
-  _flexBasis = flexBasis;
-}
-
-- (ASStackLayoutAlignSelf)alignSelf
-{
-  ASDN::MutexLocker l(_propertyLock);
-  return _alignSelf;
-}
-
-- (void)setAlignSelf:(ASStackLayoutAlignSelf)alignSelf
-{
-  ASDN::MutexLocker l(_propertyLock);
-  _alignSelf = alignSelf;
-}
-
-- (CGFloat)ascender
-{
-  ASDN::MutexLocker l(_propertyLock);
-  return _ascender;
-}
-
-- (void)setAscender:(CGFloat)ascender
-{
-  ASDN::MutexLocker l(_propertyLock);
-  _ascender = ascender;
-}
-
-- (CGFloat)descender
-{
-  ASDN::MutexLocker l(_propertyLock);
-  return _descender;
-}
-
-- (void)setDescender:(CGFloat)descender
-{
-  ASDN::MutexLocker l(_propertyLock);
-  _descender = descender;
-}
-
-- (ASRelativeSizeRange)sizeRange
-{
-  ASDN::MutexLocker l(_propertyLock);
-  return _sizeRange;
-}
-
-- (void)setSizeRange:(ASRelativeSizeRange)sizeRange
-{
-  ASDN::MutexLocker l(_propertyLock);
-  _sizeRange = sizeRange;
-}
-
-- (CGPoint)layoutPosition
-{
-  ASDN::MutexLocker l(_propertyLock);
-  return _layoutPosition;
-}
-
-- (void)setLayoutPosition:(CGPoint)layoutPosition
-{
-  ASDN::MutexLocker l(_propertyLock);
-  _layoutPosition = layoutPosition;
-}
-
-@end

AsyncDisplayKit/Layout/ASLayoutOptionsPrivate.mm

@@ -1,143 +0,0 @@
-/*
- *  Copyright (c) 2014-present, Facebook, Inc.
- *  All rights reserved.
- *
- *  This source code is licensed under the BSD-style license found in the
- *  LICENSE file in the root directory of this source tree. An additional grant
- *  of patent rights can be found in the PATENTS file in the same directory.
- *
- */
-
-#import "ASLayoutOptionsPrivate.h"
-#import <AsyncDisplayKit/ASDisplayNodeInternal.h>
-
-
-/**
- *  Both an ASDisplayNode and an ASLayoutSpec conform to ASLayoutable. There are several properties
- *  in ASLayoutable that are used as layoutOptions when a node or spec is used in a layout spec.
- *  These properties are provided for convenience, as they are forwards to the node or spec's
- *  ASLayoutOptions class. Instead of duplicating the property forwarding in both classes, we 
- *  create a define that allows us to easily implement the forwards in one place.
- *
- *  If you create a custom layout spec, we recommend this stragety if you decide to extend
- *  ASDisplayNode and ASLayoutSpec to provide convenience properties for any options that your
- *  layoutSpec may require.
- */
-#define ASLayoutOptionsForwarding \
-- (ASLayoutOptions *)layoutOptions\
-{\
-ASDN::MutexLocker l(_layoutOptionsLock);\
-if (_layoutOptions == nil) {\
-_layoutOptions = [[[ASLayoutOptions defaultLayoutOptionsClass] alloc] initWithLayoutable:self];\
-}\
-return _layoutOptions;\
-}\
-\
-- (CGFloat)spacingBefore\
-{\
-return self.layoutOptions.spacingBefore;\
-}\
-\
-- (void)setSpacingBefore:(CGFloat)spacingBefore\
-{\
-self.layoutOptions.spacingBefore = spacingBefore;\
-}\
-\
-- (CGFloat)spacingAfter\
-{\
-return self.layoutOptions.spacingAfter;\
-}\
-\
-- (void)setSpacingAfter:(CGFloat)spacingAfter\
-{\
-self.layoutOptions.spacingAfter = spacingAfter;\
-}\
-\
-- (BOOL)flexGrow\
-{\
-return self.layoutOptions.flexGrow;\
-}\
-\
-- (void)setFlexGrow:(BOOL)flexGrow\
-{\
-self.layoutOptions.flexGrow = flexGrow;\
-}\
-\
-- (BOOL)flexShrink\
-{\
-return self.layoutOptions.flexShrink;\
-}\
-\
-- (void)setFlexShrink:(BOOL)flexShrink\
-{\
-self.layoutOptions.flexShrink = flexShrink;\
-}\
-\
-- (ASRelativeDimension)flexBasis\
-{\
-return self.layoutOptions.flexBasis;\
-}\
-\
-- (void)setFlexBasis:(ASRelativeDimension)flexBasis\
-{\
-self.layoutOptions.flexBasis = flexBasis;\
-}\
-\
-- (ASStackLayoutAlignSelf)alignSelf\
-{\
-return self.layoutOptions.alignSelf;\
-}\
-\
-- (void)setAlignSelf:(ASStackLayoutAlignSelf)alignSelf\
-{\
-  self.layoutOptions.alignSelf = alignSelf;\
-}\
-\
-- (CGFloat)ascender\
-{\
-  return self.layoutOptions.ascender;\
-}\
-\
-- (void)setAscender:(CGFloat)ascender\
-{\
-  self.layoutOptions.ascender = ascender;\
-}\
-\
-- (CGFloat)descender\
-{\
-  return self.layoutOptions.descender;\
-}\
-\
-- (void)setDescender:(CGFloat)descender\
-{\
-  self.layoutOptions.descender = descender;\
-}\
-\
-- (ASRelativeSizeRange)sizeRange\
-{\
-  return self.layoutOptions.sizeRange;\
-}\
-\
-- (void)setSizeRange:(ASRelativeSizeRange)sizeRange\
-{\
-  self.layoutOptions.sizeRange = sizeRange;\
-}\
-\
-- (CGPoint)layoutPosition\
-{\
-  return self.layoutOptions.layoutPosition;\
-}\
-\
-- (void)setLayoutPosition:(CGPoint)position\
-{\
-  self.layoutOptions.layoutPosition = position;\
-}\
-
-
-@implementation ASDisplayNode(ASLayoutOptions)
-ASLayoutOptionsForwarding
-@end
-
-@implementation ASLayoutSpec(ASLayoutOptions)
-ASLayoutOptionsForwarding
-@end

AsyncDisplayKit/Layout/ASLayoutSpec.h

@@ -25,6 +25,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (instancetype)init;
 
+@property (nullable, nonatomic, weak) id<ASLayoutable> parent;
+
 /**
  * Adds a child to this layout spec using a default identifier.
  *

AsyncDisplayKit/Layout/ASLayoutSpec.mm

@@ -8,29 +8,33 @@
  *
  */
 
-#import "ASLayoutOptionsPrivate.h"
+#import "ASLayoutSpec.h"
 
 #import "ASAssert.h"
 #import "ASBaseDefines.h"
+#import "ASEnvironmentInternal.h"
 
 #import "ASInternalHelpers.h"
 #import "ASLayout.h"
-#import "ASLayoutOptions.h"
 #import "ASThread.h"
 
+
 #import <objc/runtime.h>
 
 static NSString * const kDefaultChildKey = @"kDefaultChildKey";
 static NSString * const kDefaultChildrenKey = @"kDefaultChildrenKey";
 
-@interface ASLayoutSpec()
+@interface ASLayoutSpec() {
+  ASEnvironmentState _environmentState;
+  ASDN::RecursiveMutex _propertyLock;
+}
 @property (nonatomic, strong) NSMutableDictionary *layoutChildren;
 @end
 
 @implementation ASLayoutSpec
 
 // these dynamic properties all defined in ASLayoutOptionsPrivate.m
-@dynamic spacingAfter, spacingBefore, flexGrow, flexShrink, flexBasis, alignSelf, ascender, descender, sizeRange, layoutPosition, layoutOptions;
+@dynamic spacingAfter, spacingBefore, flexGrow, flexShrink, flexBasis, alignSelf, ascender, descender, sizeRange, layoutPosition;
 @synthesize layoutChildren = _layoutChildren;
 @synthesize isFinalLayoutable = _isFinalLayoutable;
 
@@ -40,6 +44,8 @@ static NSString * const kDefaultChildrenKey = @"kDefaultChildrenKey";
     return nil;
   }
   _isMutable = YES;
+  _environmentState = ASEnvironmentStateMakeDefault();
+  
   return self;
 }
 
@@ -75,7 +81,8 @@ static NSString * const kDefaultChildrenKey = @"kDefaultChildrenKey";
 
     id<ASLayoutable> finalLayoutable = [child finalLayoutable];
     if (finalLayoutable != child) {
-      [finalLayoutable.layoutOptions copyFromOptions:child.layoutOptions];
+      // Layout options state of child needs to be copied to final layoutable
+      finalLayoutable.environmentState.layoutOptionsState = child.environmentState.layoutOptionsState;
       return finalLayoutable;
     }
   }
@@ -90,6 +97,15 @@ static NSString * const kDefaultChildrenKey = @"kDefaultChildrenKey";
   return _layoutChildren;
 }
 
+- (void)setParent:(id<ASLayoutable>)parent
+{
+  _parent = parent;
+  
+  if ([parent supportsUpwardPropagation]) {
+    ASEnvironmentStatePropagateUp(parent, _environmentState.layoutOptionsState);
+  }
+}
+
 - (void)setChild:(id<ASLayoutable>)child;
 {
   [self setChild:child forIdentifier:kDefaultChildKey];
@@ -98,7 +114,14 @@ static NSString * const kDefaultChildrenKey = @"kDefaultChildrenKey";
 - (void)setChild:(id<ASLayoutable>)child forIdentifier:(NSString *)identifier
 {
   ASDisplayNodeAssert(self.isMutable, @"Cannot set properties when layout spec is not mutable");
-  self.layoutChildren[identifier] = [self layoutableToAddFromLayoutable:child];;
+  id<ASLayoutable> finalLayoutable = [self layoutableToAddFromLayoutable:child];
+  BOOL needsToPropagateLayoutOptionsState = (child != finalLayoutable);
+  self.layoutChildren[identifier] = finalLayoutable;
+  if (needsToPropagateLayoutOptionsState) {
+    // We only need to propagate up layout options in setChild: as up propagation is currently only supported for
+    // layout specification has with one child
+    [self propagateUpLayoutOptionsState];
+  }
 }
 
 - (void)setChildren:(NSArray *)children
@@ -128,6 +151,30 @@ static NSString * const kDefaultChildrenKey = @"kDefaultChildrenKey";
   return self.layoutChildren[kDefaultChildrenKey];
 }
 
+
+#pragma mark - ASEnvironment
+
+- (ASEnvironmentState)environmentState
+{
+  return _environmentState;
+}
+
+- (void)setEnvironmentState:(ASEnvironmentState)environmentState
+{
+  _environmentState = environmentState;
+}
+
+// Subclasses can override this method to return NO, because upward propagation is not enabled if a layout
+// specification has more than one child. Currently ASStackLayoutSpec and ASStaticLayoutSpec are currently
+// the specifications that are known to have more than one.
+- (BOOL)supportsUpwardPropagation
+{
+  return YES;
+}
+
+ASEnvironmentLayoutOptionsForwarding
+ASEnvironmentLayoutExtensibilityForwarding
+
 @end
 
 @implementation ASLayoutSpec (Debugging)

AsyncDisplayKit/Layout/ASLayoutable.h

@@ -15,6 +15,8 @@
 #import <AsyncDisplayKit/ASStaticLayoutable.h>
 
 #import <AsyncDisplayKit/ASLayoutablePrivate.h>
+#import <AsyncDisplayKit/ASEnvironment.h>
+#import <AsyncDisplayKit/ASLayoutableExtensibility.h>
 
 @class ASLayout;
 @class ASLayoutSpec;
@@ -37,7 +39,7 @@ NS_ASSUME_NONNULL_BEGIN
  * access to the options via convenience properties. If you are creating custom layout spec, then you can
  * extend the backing layout options class to accommodate any new layout options.
  */
-@protocol ASLayoutable <ASStackLayoutable, ASStaticLayoutable, ASLayoutablePrivate>
+@protocol ASLayoutable <ASEnvironment, ASStackLayoutable, ASStaticLayoutable, ASLayoutablePrivate, ASLayoutableExtensibility>
 
 /**
  * @abstract Calculate a layout based on given size range.

AsyncDisplayKit/Layout/ASLayoutable.mm

@@ -7,6 +7,12 @@
 //
 
 #import "ASLayoutablePrivate.h"
+#import "ASInternalHelpers.h"
+#import "ASEnvironmentInternal.h"
+#import "ASDisplayNodeInternal.h"
+#import "ASTextNode.h"
+#import "ASLayoutSpec.h"
+
 #import "pthread.h"
 #import <map>
 #import <iterator>

AsyncDisplayKit/Layout/ASLayoutableExtensibility.h

@@ -0,0 +1,25 @@
+//
+//  ASLayoutableExtensibility.h
+//  AsyncDisplayKit
+//
+//  Created by Michael Schneider on 3/29/16.
+//  Copyright © 2016 Facebook. All rights reserved.
+//
+
+#import <UIKit/UIGeometry.h>
+
+@protocol ASLayoutableExtensibility <NSObject>
+
+/// Currently up to 4 BOOL values
+- (void)setLayoutOptionExtensionBool:(BOOL)value atIndex:(int)idx;
+- (BOOL)layoutOptionExtensionBoolAtIndex:(int)idx;
+
+/// Currently up to 1 NSInteger value
+- (void)setLayoutOptionExtensionInteger:(NSInteger)value atIndex:(int)idx;
+- (NSInteger)layoutOptionExtensionIntegerAtIndex:(int)idx;
+
+/// Currently up to 1 UIEdgeInsets value
+- (void)setLayoutOptionExtensionEdgeInsets:(UIEdgeInsets)value atIndex:(int)idx;
+- (UIEdgeInsets)layoutOptionExtensionEdgeInsetsAtIndex:(int)idx;
+
+@end

AsyncDisplayKit/Layout/ASLayoutablePrivate.h

@@ -11,7 +11,6 @@
 #import <Foundation/Foundation.h>
 
 @class ASLayoutSpec;
-@class ASLayoutOptions;
 @protocol ASLayoutable;
 
 struct ASLayoutableContext {
@@ -60,9 +59,211 @@ extern void ASLayoutableClearCurrentContext();
  */
 @property (nonatomic, assign) BOOL isFinalLayoutable;
 
+@end
+
+
+#pragma mark - ASLayoutOptionsForwarding
 
 /**
- *  The class that holds all of the layoutOptions set on an ASLayoutable.
+ *  Both an ASDisplayNode and an ASLayoutSpec conform to ASLayoutable. There are several properties
+ *  in ASLayoutable that are used when a node or spec is used in a layout spec.
+ *  These properties are provided for convenience, as they are forwards to the node or spec's
+ *  properties. Instead of duplicating the property forwarding in both classes, we
+ *  create a define that allows us to easily implement the forwards in one place.
+ *
+ *  If you create a custom layout spec, we recommend this stragety if you decide to extend
+ *  ASDisplayNode and ASLayoutSpec to provide convenience properties for any options that your
+ *  layoutSpec may require.
  */
-@property (nonatomic, strong, readonly) ASLayoutOptions *layoutOptions;
+
-@end
+#define ASEnvironmentLayoutOptionsForwarding \
+- (void)propagateUpLayoutOptionsState\
+{\
+  id<ASEnvironment> parent = [self parent];\
+  if ([parent supportsUpwardPropagation]) {\
+    ASEnvironmentStatePropagateUp(parent, _environmentState.layoutOptionsState);\
+  }\
+}\
+\
+- (CGFloat)spacingAfter\
+{\
+  ASDN::MutexLocker l(_propertyLock);\
+  return _environmentState.layoutOptionsState.spacingAfter;\
+}\
+\
+- (void)setSpacingAfter:(CGFloat)spacingAfter\
+{\
+  _propertyLock.lock();\
+  _environmentState.layoutOptionsState.spacingAfter = spacingAfter;\
+  [self propagateUpLayoutOptionsState];\
+  _propertyLock.unlock();\
+}\
+\
+- (CGFloat)spacingBefore\
+{\
+  ASDN::MutexLocker l(_propertyLock);\
+  return _environmentState.layoutOptionsState.spacingBefore;\
+}\
+\
+- (void)setSpacingBefore:(CGFloat)spacingBefore\
+{\
+  _propertyLock.lock();\
+  _environmentState.layoutOptionsState.spacingBefore = spacingBefore;\
+  [self propagateUpLayoutOptionsState];\
+  _propertyLock.unlock();\
+}\
+\
+- (BOOL)flexGrow\
+{\
+  ASDN::MutexLocker l(_propertyLock);\
+  return _environmentState.layoutOptionsState.flexGrow;\
+}\
+\
+- (void)setFlexGrow:(BOOL)flexGrow\
+{\
+  _propertyLock.lock();\
+  _environmentState.layoutOptionsState.flexGrow = flexGrow;\
+  [self propagateUpLayoutOptionsState];\
+  _propertyLock.unlock();\
+}\
+\
+- (BOOL)flexShrink\
+{\
+  ASDN::MutexLocker l(_propertyLock);\
+  return _environmentState.layoutOptionsState.flexShrink;\
+}\
+\
+- (void)setFlexShrink:(BOOL)flexShrink\
+{\
+  _propertyLock.lock();\
+  _environmentState.layoutOptionsState.flexShrink = flexShrink;\
+  [self propagateUpLayoutOptionsState];\
+  _propertyLock.unlock();\
+}\
+\
+- (ASRelativeDimension)flexBasis\
+{\
+  ASDN::MutexLocker l(_propertyLock);\
+  return _environmentState.layoutOptionsState.flexBasis;\
+}\
+\
+- (void)setFlexBasis:(ASRelativeDimension)flexBasis\
+{\
+  _propertyLock.lock();\
+  _environmentState.layoutOptionsState.flexBasis = flexBasis;\
+  [self propagateUpLayoutOptionsState];\
+  _propertyLock.unlock();\
+}\
+\
+- (ASStackLayoutAlignSelf)alignSelf\
+{\
+  ASDN::MutexLocker l(_propertyLock);\
+  return _environmentState.layoutOptionsState.alignSelf;\
+}\
+\
+- (void)setAlignSelf:(ASStackLayoutAlignSelf)alignSelf\
+{\
+  _propertyLock.lock();\
+  _environmentState.layoutOptionsState.alignSelf = alignSelf;\
+  [self propagateUpLayoutOptionsState];\
+  _propertyLock.unlock();\
+}\
+\
+- (CGFloat)ascender\
+{\
+  ASDN::MutexLocker l(_propertyLock);\
+  return _environmentState.layoutOptionsState.ascender;\
+}\
+\
+- (void)setAscender:(CGFloat)ascender\
+{\
+  _propertyLock.lock();\
+  _environmentState.layoutOptionsState.ascender = ascender;\
+  [self propagateUpLayoutOptionsState];\
+  _propertyLock.unlock();\
+}\
+\
+- (CGFloat)descender\
+{\
+  ASDN::MutexLocker l(_propertyLock);\
+  return _environmentState.layoutOptionsState.descender;\
+}\
+\
+- (void)setDescender:(CGFloat)descender\
+{\
+  _propertyLock.lock();\
+  _environmentState.layoutOptionsState.descender = descender;\
+  [self propagateUpLayoutOptionsState];\
+  _propertyLock.unlock();\
+}\
+\
+- (ASRelativeSizeRange)sizeRange\
+{\
+  ASDN::MutexLocker l(_propertyLock);\
+  return _environmentState.layoutOptionsState.sizeRange;\
+}\
+\
+- (void)setSizeRange:(ASRelativeSizeRange)sizeRange\
+{\
+  _propertyLock.lock();\
+  _environmentState.layoutOptionsState.sizeRange = sizeRange;\
+  [self propagateUpLayoutOptionsState];\
+  _propertyLock.unlock();\
+}\
+\
+- (CGPoint)layoutPosition\
+{\
+  ASDN::MutexLocker l(_propertyLock);\
+  return _environmentState.layoutOptionsState.layoutPosition;\
+}\
+\
+- (void)setLayoutPosition:(CGPoint)layoutPosition\
+{\
+  _propertyLock.lock();\
+  _environmentState.layoutOptionsState.layoutPosition = layoutPosition;\
+  [self propagateUpLayoutOptionsState];\
+  _propertyLock.unlock();\
+}\
+
+
+#pragma mark - ASLayoutableExtensibility
+
+#define ASEnvironmentLayoutExtensibilityForwarding \
+- (void)setLayoutOptionExtensionBool:(BOOL)value atIndex:(int)idx\
+{\
+  _propertyLock.lock();\
+  _ASEnvironmentLayoutOptionsExtensionSetBoolAtIndex(self, idx, value);\
+  _propertyLock.unlock();\
+}\
+\
+- (BOOL)layoutOptionExtensionBoolAtIndex:(int)idx\
+{\
+  ASDN::MutexLocker l(_propertyLock);\
+  return _ASEnvironmentLayoutOptionsExtensionGetBoolAtIndex(self, idx);\
+}\
+\
+- (void)setLayoutOptionExtensionInteger:(NSInteger)value atIndex:(int)idx\
+{\
+  _propertyLock.lock();\
+  _ASEnvironmentLayoutOptionsExtensionSetIntegerAtIndex(self, idx, value);\
+  _propertyLock.unlock();\
+}\
+\
+- (NSInteger)layoutOptionExtensionIntegerAtIndex:(int)idx\
+{\
+  ASDN::MutexLocker l(_propertyLock);\
+  return _ASEnvironmentLayoutOptionsExtensionGetIntegerAtIndex(self, idx);\
+}\
+\
+- (void)setLayoutOptionExtensionEdgeInsets:(UIEdgeInsets)value atIndex:(int)idx\
+{\
+  _propertyLock.lock();\
+  _ASEnvironmentLayoutOptionsExtensionSetEdgeInsetsAtIndex(self, idx, value);\
+  _propertyLock.unlock();\
+}\
+\
+- (UIEdgeInsets)layoutOptionExtensionEdgeInsetsAtIndex:(int)idx\
+{\
+  ASDN::MutexLocker l(_propertyLock);\
+  return _ASEnvironmentLayoutOptionsExtensionGetEdgeInsetsAtIndex(self, idx);\
+}\

AsyncDisplayKit/Layout/ASStackLayoutSpec.mm

@@ -198,6 +198,15 @@
 
 @end
 
+@implementation ASStackLayoutSpec (ASEnvironment)
+
+- (BOOL)supportsUpwardPropagation
+{
+  return NO;
+}
+
+@end
+
 @implementation ASStackLayoutSpec (Debugging)
 
 #pragma mark - ASLayoutableAsciiArtProtocol

AsyncDisplayKit/Layout/ASStaticLayoutSpec.mm

@@ -11,7 +11,6 @@
 #import "ASStaticLayoutSpec.h"
 
 #import "ASLayoutSpecUtilities.h"
-#import "ASLayoutOptions.h"
 #import "ASInternalHelpers.h"
 #import "ASLayout.h"
 
@@ -86,6 +85,15 @@
 
 @end
 
+@implementation ASStaticLayoutSpec (ASEnvironment)
+
+- (BOOL)supportsUpwardPropagation
+{
+  return NO;
+}
+
+@end
+
 @implementation ASStaticLayoutSpec (Debugging)
 
 #pragma mark - ASLayoutableAsciiArtProtocol

AsyncDisplayKit/Private/ASDisplayNode+FrameworkPrivate.h

@@ -16,7 +16,6 @@
 #import "ASDisplayNode.h"
 #import "ASSentinel.h"
 #import "ASThread.h"
-#import "ASLayoutOptions.h"
 #import "_ASDisplayLayer.h"
 
 NS_ASSUME_NONNULL_BEGIN

AsyncDisplayKit/Private/ASDisplayNodeInternal.h

@@ -16,9 +16,9 @@
 #import "ASDisplayNode.h"
 #import "ASSentinel.h"
 #import "ASThread.h"
-#import "ASLayoutOptions.h"
 #import "_ASTransitionContext.h"
 #import "ASDisplayNodeLayoutContext.h"
+#import "ASEnvironment.h"
 
 #include <vector>
 
@@ -97,6 +97,7 @@ FOUNDATION_EXPORT NSString * const ASRenderingEngineDidDisplayNodesScheduledBefo
   // This is the desired contentsScale, not the scale at which the layer's contents should be displayed
   CGFloat _contentsScaleForDisplay;
 
+  ASEnvironmentState _environmentState;
   ASLayout *_layout;
 
   ASSizeRange _constrainedSize;

AsyncDisplayKit/Private/ASEnvironmentInternal.h

@@ -0,0 +1,69 @@
+/*
+ *  Copyright (c) 2014-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
+#import "ASEnvironment.h"
+
+#pragma once
+
+enum class ASEnvironmentStatePropagation { DOWN, UP };
+
+
+#pragma mark - Set and get extensible values for layout options
+
+void _ASEnvironmentLayoutOptionsExtensionSetBoolAtIndex(id<ASEnvironment> object, int idx, BOOL value);
+BOOL _ASEnvironmentLayoutOptionsExtensionGetBoolAtIndex(id<ASEnvironment> object, int idx);
+
+void _ASEnvironmentLayoutOptionsExtensionSetIntegerAtIndex(id<ASEnvironment> object, int idx, NSInteger value);
+NSInteger _ASEnvironmentLayoutOptionsExtensionGetIntegerAtIndex(id<ASEnvironment> object, int idx);
+
+void _ASEnvironmentLayoutOptionsExtensionSetEdgeInsetsAtIndex(id<ASEnvironment> object, int idx, UIEdgeInsets value);
+UIEdgeInsets _ASEnvironmentLayoutOptionsExtensionGetEdgeInsetsAtIndex(id<ASEnvironment> object, int idx);
+
+
+#pragma mark - Traversing an ASEnvironment Tree
+
+void ASEnvironmentPerformBlockOnObjectAndChildren(id<ASEnvironment> object, void(^block)(id<ASEnvironment> object));
+void ASEnvironmentPerformBlockOnObjectAndParents(id<ASEnvironment> object, void(^block)(id<ASEnvironment> object));
+
+
+#pragma mark - Merging
+
+static const struct ASEnvironmentLayoutOptionsState ASEnvironmentDefaultLayoutOptionsState = {};
+ASEnvironmentState ASEnvironmentMergeObjectAndState(ASEnvironmentState environmentState, ASEnvironmentLayoutOptionsState state, ASEnvironmentStatePropagation propagation);
+
+
+static const struct ASEnvironmentHierarchyState ASEnvironmentDefaultHierarchyState = {};
+ASEnvironmentState ASEnvironmentMergeObjectAndState(ASEnvironmentState environmentState, ASEnvironmentHierarchyState state, ASEnvironmentStatePropagation propagation);
+
+
+#pragma mark - Propagation
+
+template <typename ASEnvironmentStateType>
+void ASEnvironmentStatePropagateDown(id<ASEnvironment> object, ASEnvironmentStateType state) {
+  ASEnvironmentPerformBlockOnObjectAndChildren(object, ^(id<ASEnvironment> node) {
+    object.environmentState = ASEnvironmentMergeObjectAndState(object.environmentState, state, ASEnvironmentStatePropagation::DOWN);
+  });
+}
+
+template <typename ASEnvironmentStateType>
+void ASEnvironmentStatePropagateUp(id<ASEnvironment> object, ASEnvironmentStateType state) {
+  ASEnvironmentPerformBlockOnObjectAndParents(object, ^(id<ASEnvironment> node) {
+    object.environmentState = ASEnvironmentMergeObjectAndState(object.environmentState, state, ASEnvironmentStatePropagation::UP);
+  });
+}
+
+template <typename ASEnvironmentStateType>
+void ASEnvironmentStateApply(id<ASEnvironment> object, ASEnvironmentStateType& state, ASEnvironmentStatePropagation propagate) {
+  if (propagate == ASEnvironmentStatePropagation::DOWN) {
+    ASEnvironmentStatePropagateUp(object, state);
+  } else if (propagate == ASEnvironmentStatePropagation::UP) {
+    ASEnvironmentStatePropagateDown(object, state);
+  }
+}

AsyncDisplayKit/Private/ASEnvironmentInternal.mm

@@ -0,0 +1,151 @@
+/*
+ *  Copyright (c) 2014-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
+#import "ASEnvironmentInternal.h"
+
+#import <queue>
+
+//#define LOG(...) NSLog(__VA_ARGS__)
+#define LOG(...)
+
+#pragma mark - Traversing an ASEnvironment Tree
+
+void ASEnvironmentPerformBlockOnObjectAndChildren(id<ASEnvironment> object, void(^block)(id<ASEnvironment> node))
+{
+  if (!object) {
+    return;
+  }
+  
+  std::queue<id<ASEnvironment>> queue;
+  queue.push(object);
+  
+  while (!queue.empty()) {
+    id<ASEnvironment> object = queue.front(); queue.pop();
+    
+    block(object);
+    
+    for (id<ASEnvironment> child in [object children]) {
+      queue.push(child);
+    }
+  }
+}
+
+void ASEnvironmentPerformBlockOnObjectAndParents(id<ASEnvironment> object, void(^block)(id<ASEnvironment> node))
+{
+  while (object) {
+    block(object);
+    object = [object parent];
+  }
+}
+
+
+#pragma mark - Set and get extensible values from state structs
+
+void _ASEnvironmentLayoutOptionsExtensionSetBoolAtIndex(id<ASEnvironment> object, int idx, BOOL value)
+{
+  NSCAssert(idx < kMaxEnvironmentStateBoolExtensions, @"Setting index outside of max bool extensions space");
+  
+  ASEnvironmentStateExtensions extension = object.environmentState.layoutOptionsState._extensions;
+  extension.boolExtensions[idx] = value;
+  object.environmentState.layoutOptionsState._extensions = extension;
+}
+
+BOOL _ASEnvironmentLayoutOptionsExtensionGetBoolAtIndex(id<ASEnvironment> object, int idx)
+{
+  NSCAssert(idx < kMaxEnvironmentStateBoolExtensions, @"Accessing index outside of max bool extensions space");
+  return object.environmentState.layoutOptionsState._extensions.boolExtensions[idx];
+}
+
+void _ASEnvironmentLayoutOptionsExtensionSetIntegerAtIndex(id<ASEnvironment> object, int idx, NSInteger value)
+{
+  NSCAssert(idx < kMaxEnvironmentStateIntegerExtensions, @"Setting index outside of max integer extensions space");
+  
+  ASEnvironmentStateExtensions extension = object.environmentState.layoutOptionsState._extensions;
+  extension.integerExtensions[idx] = value;
+  object.environmentState.layoutOptionsState._extensions = extension;
+}
+
+NSInteger _ASEnvironmentLayoutOptionsExtensionGetIntegerAtIndex(id<ASEnvironment> object, int idx)
+{
+  NSCAssert(idx < kMaxEnvironmentStateIntegerExtensions, @"Accessing index outside of max integer extensions space");
+  return object.environmentState.layoutOptionsState._extensions.integerExtensions[idx];
+}
+
+void _ASEnvironmentLayoutOptionsExtensionSetEdgeInsetsAtIndex(id<ASEnvironment> object, int idx, UIEdgeInsets value)
+{
+  NSCAssert(idx < kMaxEnvironmentStateEdgeInsetExtensions, @"Setting index outside of max edge insets extensions space");
+  
+  ASEnvironmentStateExtensions extension = object.environmentState.layoutOptionsState._extensions;
+  extension.edgeInsetsExtensions[idx] = value;
+  object.environmentState.layoutOptionsState._extensions = extension;
+}
+
+UIEdgeInsets _ASEnvironmentLayoutOptionsExtensionGetEdgeInsetsAtIndex(id<ASEnvironment> object, int idx)
+{
+  NSCAssert(idx < kMaxEnvironmentStateEdgeInsetExtensions, @"Accessing index outside of max edge insets extensions space");
+  return object.environmentState.layoutOptionsState._extensions.edgeInsetsExtensions[idx];
+}
+
+
+#pragma mark - Merging functions for states
+
+ASEnvironmentState ASEnvironmentMergeObjectAndState(ASEnvironmentState environmentState, ASEnvironmentHierarchyState state, ASEnvironmentStatePropagation propagation) {
+    // Merge object and hierarchy state
+  LOG(@"Merge object and state: %@ - ASEnvironmentHierarchyState", object);
+  return environmentState;
+}
+
+ASEnvironmentState ASEnvironmentMergeObjectAndState(ASEnvironmentState environmentState, ASEnvironmentLayoutOptionsState state, ASEnvironmentStatePropagation propagation) {
+  // Merge object and layout options state
+  LOG(@"Merge object and state: %@ - ASEnvironmentLayoutOptionsState", object);
+  
+  // Support propagate up
+  if (propagation == ASEnvironmentStatePropagation::UP) {
+
+   // Object is the parent and the state is the state of the child
+    const ASEnvironmentLayoutOptionsState defaultState = ASEnvironmentDefaultLayoutOptionsState;
+    ASEnvironmentLayoutOptionsState parentState = environmentState.layoutOptionsState;
+    
+    // For every field check if the parent value is equal to the default than propegate up the child value to
+    // the parent
+    if (parentState.spacingBefore != defaultState.spacingBefore) {
+      parentState.spacingBefore = state.spacingBefore;
+    }
+    if (parentState.spacingAfter != defaultState.spacingAfter) {
+      parentState.spacingAfter = state.spacingAfter;
+    }
+    if (parentState.alignSelf != defaultState.alignSelf) {
+      parentState.alignSelf = defaultState.alignSelf;
+    }
+    if (parentState.flexGrow != defaultState.flexGrow) {
+      parentState.flexGrow = defaultState.flexGrow;
+    }
+    if (!ASRelativeDimensionEqualToRelativeDimension(parentState.flexBasis, defaultState.flexBasis)) {
+      parentState.flexBasis = defaultState.flexBasis;
+    }
+    if (parentState.alignSelf != defaultState.alignSelf) {
+      parentState.alignSelf = defaultState.alignSelf;
+    }
+    if (parentState.ascender != defaultState.ascender) {
+      parentState.ascender = defaultState.ascender;
+    }
+    
+    if (!ASRelativeSizeRangeEqualToRelativeSizeRange(parentState.sizeRange, defaultState.sizeRange)) {
+      parentState.sizeRange = defaultState.sizeRange;
+    }
+    if (CGPointEqualToPoint(parentState.layoutPosition, defaultState.layoutPosition)) {
+      parentState.layoutPosition = defaultState.layoutPosition;
+    }
+    
+    environmentState.layoutOptionsState = parentState;
+  }
+  
+  return environmentState;
+}

AsyncDisplayKit/Private/ASLayoutOptionsPrivate.h

@@ -1,33 +0,0 @@
-/*
- *  Copyright (c) 2014-present, Facebook, Inc.
- *  All rights reserved.
- *
- *  This source code is licensed under the BSD-style license found in the
- *  LICENSE file in the root directory of this source tree. An additional grant
- *  of patent rights can be found in the PATENTS file in the same directory.
- *
- */
-
-#import <AsyncDisplayKit/ASDisplayNode.h>
-#import <AsyncDisplayKit/ASLayoutSpec.h>
-#import <AsyncDisplayKit/ASThread.h>
-
-@interface ASDisplayNode(ASLayoutOptions)<ASLayoutable>
-@end
-
-@interface ASDisplayNode()
-{
-  ASLayoutOptions *_layoutOptions;
-  ASDN::RecursiveMutex _layoutOptionsLock;
-}
-@end
-
-@interface ASLayoutSpec(ASLayoutOptions)<ASLayoutable>
-@end
-
-@interface ASLayoutSpec()
-{
-  ASLayoutOptions *_layoutOptions;
-  ASDN::RecursiveMutex _layoutOptionsLock;
-}
-@end

AsyncDisplayKit/Private/ASStackBaselinePositionedLayout.mm

@@ -12,7 +12,6 @@
 
 #import "ASLayoutSpecUtilities.h"
 #import "ASStackLayoutSpecUtilities.h"
-#import "ASLayoutOptions.h"
 
 static CGFloat baselineForItem(const ASStackLayoutSpecStyle &style,
                                const ASLayout *layout) {

AsyncDisplayKit/Private/ASStackPositionedLayout.mm

@@ -14,7 +14,6 @@
 #import "ASLayoutSpecUtilities.h"
 #import "ASStackLayoutSpecUtilities.h"
 #import "ASLayoutable.h"
-#import "ASLayoutOptions.h"
 #import "ASAssert.h"
 
 static CGFloat crossOffset(const ASStackLayoutSpecStyle &style,

AsyncDisplayKit/Private/ASStackUnpositionedLayout.mm

@@ -14,7 +14,6 @@
 
 #import "ASLayoutSpecUtilities.h"
 #import "ASStackLayoutSpecUtilities.h"
-#import "ASLayoutOptions.h"
 
 /**
  Sizes the child given the parameters specified, and returns the computed layout.
@@ -116,8 +115,7 @@ static CGFloat computeStackDimensionSum(const std::vector<ASStackUnpositionedIte
                                                   children.empty() ? 0 : style.spacing * (children.size() - 1),
                                                   [&](CGFloat x, const ASStackUnpositionedItem &l) {
                                                     const id<ASLayoutable> child = l.child;
-                                                    const ASLayoutOptions *layoutOptions = child.layoutOptions;
+                                                    return x + child.spacingBefore + child.spacingAfter;
-                                                    return x + layoutOptions.spacingBefore + layoutOptions.spacingAfter;
                                                   });
 
   // Sum up the childrens' dimensions (including spacing) in the stack direction.

AsyncDisplayKitTests/ASCenterLayoutSpecSnapshotTests.mm

@@ -13,7 +13,6 @@
 #import "ASBackgroundLayoutSpec.h"
 #import "ASCenterLayoutSpec.h"
 #import "ASStackLayoutSpec.h"
-#import "ASLayoutOptions.h"
 
 static const ASSizeRange kSize = {{100, 120}, {320, 160}};
 

AsyncDisplayKitTests/ASRelativeLayoutSpecSnapshotTests.mm

@@ -13,7 +13,6 @@
 #import "ASBackgroundLayoutSpec.h"
 #import "ASRelativeLayoutSpec.h"
 #import "ASStackLayoutSpec.h"
-#import "ASLayoutOptions.h"
 
 static const ASSizeRange kSize = {{100, 120}, {320, 160}};
 

AsyncDisplayKitTests/ASStackLayoutSpecSnapshotTests.mm

@@ -15,7 +15,6 @@
 #import "ASBackgroundLayoutSpec.h"
 #import "ASRatioLayoutSpec.h"
 #import "ASInsetLayoutSpec.h"
-#import "ASLayoutOptions.h"
 
 @interface ASStackLayoutSpecSnapshotTests : ASLayoutSpecSnapshotTestCase
 @end