Merge remote-tracking branch 'facebook/master' into 500pxgram

2026-01-05 20:52:48 +00:00 · 2016-04-04 20:33:14 -07:00
parent caf2e43d57 0ef9d295b9
commit e07827bf64
67 changed files with 1119 additions and 723 deletions
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,8 +1,8 @@
 language: objective-c
-osx_image: xcode7.2
+osx_image: xcode7.3
 before_install:
  - brew update
-  - brew reinstall xctool
+  - brew reinstall --HEAD xctool
  - brew reinstall carthage
  - gem install cocoapods -v 0.38.2
  - gem install slather
--- a/AsyncDisplayKit.podspec
+++ b/AsyncDisplayKit.podspec
@@ -1,6 +1,6 @@
 Pod::Spec.new do |spec|
  spec.name         = 'AsyncDisplayKit'
-  spec.version      = '1.9.7.1'
+  spec.version      = '1.9.8'
  spec.license      =  { :type => 'BSD' }
  spec.homepage     = 'http://asyncdisplaykit.org'
  spec.authors      = { 'Scott Goodson' => 'scottgoodson@gmail.com', 'Ryan Nystrom' => 'rnystrom@fb.com' }
@@ -14,7 +14,8 @@ Pod::Spec.new do |spec|
      'AsyncDisplayKit/Details/**/*.h',
      'AsyncDisplayKit/Layout/*.h',
      'Base/*.h',
-      'AsyncDisplayKit/TextKit/ASTextNodeTypes.h'
+      'AsyncDisplayKit/TextKit/ASTextNodeTypes.h',
+      'AsyncDisplayKit/TextKit/ASTextKitComponents.h'
  ]

  spec.source_files = [
--- a/AsyncDisplayKit.xcodeproj/project.pbxproj
+++ b/AsyncDisplayKit.xcodeproj/project.pbxproj
@@ -136,7 +136,7 @@
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-		254C6B751BF94DF4003EC431 /* ASTextKitHelpers.h in Headers */ = {isa = PBXBuildFile; fileRef = 257754BA1BEE458E00737CA5 /* ASTextKitHelpers.h */; };
+		254C6B751BF94DF4003EC431 /* ASTextKitComponents.h in Headers */ = {isa = PBXBuildFile; fileRef = 257754BA1BEE458E00737CA5 /* ASTextKitComponents.h */; settings = {ATTRIBUTES = (Public, ); }; };
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@@ -148,7 +148,7 @@
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+		254C6B821BF94F8A003EC431 /* ASTextKitComponents.m in Sources */ = {isa = PBXBuildFile; fileRef = 257754B71BEE458D00737CA5 /* ASTextKitComponents.m */; };
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-		257754BE1BEE458E00737CA5 /* ASTextKitHelpers.mm in Sources */ = {isa = PBXBuildFile; fileRef = 257754B71BEE458D00737CA5 /* ASTextKitHelpers.mm */; };
+		257754BE1BEE458E00737CA5 /* ASTextKitComponents.m in Sources */ = {isa = PBXBuildFile; fileRef = 257754B71BEE458D00737CA5 /* ASTextKitComponents.m */; };
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+		257754C11BEE458E00737CA5 /* ASTextKitComponents.h in Headers */ = {isa = PBXBuildFile; fileRef = 257754BA1BEE458E00737CA5 /* ASTextKitComponents.h */; settings = {ATTRIBUTES = (Public, ); }; };
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+		ACF6ED191B17843500DA7C62 /* ASStaticLayoutSpec.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; lineEnding = 0; name = ASStaticLayoutSpec.mm; path = AsyncDisplayKit/Layout/ASStaticLayoutSpec.mm; sourceTree = "<group>"; };
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@@ -1116,14 +1119,6 @@
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 			isa = PBXGroup;
 			children = (
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-				81EE384E1C8E94F000456208 /* ASRunLoopQueue.mm */,
-				CC7FD9DC1BB5E962005CCB2B /* ASPhotosFrameworkImageRequest.h */,
-				CC7FD9DD1BB5E962005CCB2B /* ASPhotosFrameworkImageRequest.m */,
-				251B8EF41BBB3D690087C538 /* ASCollectionViewFlowLayoutInspector.h */,
-				251B8EF51BBB3D690087C538 /* ASCollectionViewFlowLayoutInspector.m */,
-				251B8EF61BBB3D690087C538 /* ASDataController+Subclasses.h */,
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 				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 */,
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 				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 */,
-				0442850C1BAA64EC00D16268 /* ASMultidimensionalArrayUtils.mm */,
-				AEB7B0181C5962EA00662EF4 /* ASDefaultPlayButton.h */,
-				AEB7B0191C5962EA00662EF4 /* ASDefaultPlayButton.m */,
+				CC3B20871C3F7A5400798563 /* ASWeakSet.h */,
+				CC3B20881C3F7A5400798563 /* ASWeakSet.m */,
 				DBC452D91C5BF64600B16017 /* NSArray+Diffing.h */,
 				DBC452DA1C5BF64600B16017 /* NSArray+Diffing.m */,
 			);
@@ -1254,11 +1260,11 @@
 			children = (
 				B30BF6501C5964B0004FCD53 /* ASLayoutManager.h */,
 				B30BF6511C5964B0004FCD53 /* ASLayoutManager.m */,
-				257754B71BEE458D00737CA5 /* ASTextKitHelpers.mm */,
+				257754BA1BEE458E00737CA5 /* ASTextKitComponents.h */,
+				257754B71BEE458D00737CA5 /* ASTextKitComponents.m */,
 				257754BB1BEE458E00737CA5 /* ASTextKitCoreTextAdditions.h */,
 				257754B81BEE458E00737CA5 /* ASTextKitCoreTextAdditions.m */,
 				257754B91BEE458E00737CA5 /* ASTextNodeWordKerner.h */,
-				257754BA1BEE458E00737CA5 /* ASTextKitHelpers.h */,
 				257754BC1BEE458E00737CA5 /* ASTextNodeTypes.h */,
 				257754BD1BEE458E00737CA5 /* ASTextNodeWordKerner.m */,
 				257754941BEE44CD00737CA5 /* ASTextKitAttributes.mm */,
@@ -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 */,
@@ -1500,7 +1505,7 @@
 				ACF6ED311B17843500DA7C62 /* ASStaticLayoutSpec.h in Headers */,
 				055F1A3419ABD3E3004DAFF1 /* ASTableView.h in Headers */,
 				251B8EF71BBB3D690087C538 /* ASCollectionDataController.h in Headers */,
-				257754C11BEE458E00737CA5 /* ASTextKitHelpers.h in Headers */,
+				257754C11BEE458E00737CA5 /* ASTextKitComponents.h in Headers */,
 				B30BF6521C5964B0004FCD53 /* ASLayoutManager.h in Headers */,
 				0574D5E219C110940097DC25 /* ASTableViewProtocols.h in Headers */,
 				81EE384F1C8E94F000456208 /* ASRunLoopQueue.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 */,
@@ -1621,7 +1626,7 @@
 				DB55C2671C641AE4004EDCF5 /* ASContextTransitioning.h in Headers */,
 				68B0277B1C1A79D60041016B /* ASDisplayNode+Beta.h in Headers */,
 				B350622D1B010EFD0018CF92 /* ASScrollDirection.h in Headers */,
-				254C6B751BF94DF4003EC431 /* ASTextKitHelpers.h in Headers */,
+				254C6B751BF94DF4003EC431 /* ASTextKitComponents.h in Headers */,
 				B35062081B010EFD0018CF92 /* ASScrollNode.h in Headers */,
 				25E327571C16819500A2170C /* ASPagerNode.h in Headers */,
 				B35062551B010EFD0018CF92 /* ASSentinel.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 */,
@@ -1741,6 +1747,7 @@
 		058D09A4195D04C000B7D73C /* Project object */ = {
 			isa = PBXProject;
 			attributes = {
+				CLASSPREFIX = AS;
 				LastUpgradeCheck = 0720;
 				ORGANIZATIONNAME = Facebook;
 				TargetAttributes = {
@@ -1872,6 +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 */,
@@ -1915,10 +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 */,
@@ -1947,7 +1954,7 @@
 				9C8221971BA237B80037F19A /* ASStackBaselinePositionedLayout.mm in Sources */,
 				251B8EF81BBB3D690087C538 /* ASCollectionDataController.mm in Sources */,
 				ACF6ED301B17843500DA7C62 /* ASStackLayoutSpec.mm in Sources */,
-				257754BE1BEE458E00737CA5 /* ASTextKitHelpers.mm in Sources */,
+				257754BE1BEE458E00737CA5 /* ASTextKitComponents.m in Sources */,
 				257754A91BEE44CD00737CA5 /* ASTextKitContext.mm in Sources */,
 				ACF6ED501B17847A00DA7C62 /* ASStackPositionedLayout.mm in Sources */,
 				ACF6ED521B17847A00DA7C62 /* ASStackUnpositionedLayout.mm in Sources */,
@@ -2026,6 +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 */,
@@ -2055,6 +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 */,
@@ -2067,13 +2076,11 @@
 				B350621E1B010EFD0018CF92 /* ASHighlightOverlayLayer.mm in Sources */,
 				B35062541B010EFD0018CF92 /* ASImageNode+CGExtras.m in Sources */,
 				B35062031B010EFD0018CF92 /* ASImageNode.mm in Sources */,
-				254C6B821BF94F8A003EC431 /* ASTextKitHelpers.mm in Sources */,
+				254C6B821BF94F8A003EC431 /* ASTextKitComponents.m in Sources */,
 				430E7C921B4C23F100697A4C /* ASIndexPath.m in Sources */,
 				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 */,
--- a/AsyncDisplayKit/ASDisplayNode.mm
+++ b/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
@@ -1854,6 +1856,7 @@ void recursivelyTriggerDisplayForLayer(CALayer *layer, BOOL shouldBlock)
  ASDN::MutexLocker l(_propertyLock);
  if (_methodOverrides & ASDisplayNodeMethodOverrideLayoutSpecThatFits) {
    ASLayoutSpec *layoutSpec = [self layoutSpecThatFits:constrainedSize];
+    layoutSpec.parent = self; // This causes upward propogation of any non-default layoutable values.
    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 +1921,7 @@ 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 +2670,37 @@ 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)

--- a/AsyncDisplayKit/ASEditableTextNode.h
+++ b/AsyncDisplayKit/ASEditableTextNode.h
@@ -7,6 +7,7 @@
 */

 #import <AsyncDisplayKit/ASDisplayNode.h>
+#import <AsyncDisplayKit/ASTextKitComponents.h>

 NS_ASSUME_NONNULL_BEGIN

@@ -18,6 +19,24 @@ NS_ASSUME_NONNULL_BEGIN
 */
@interface ASEditableTextNode : ASDisplayNode

+/**
+ * @abstract Initializes an editable text node using default TextKit components.
+ *
+ * @returns An initialized ASEditableTextNode.
+ */
+- (instancetype)init;
+
+/**
+ * @abstract Initializes an editable text node using the provided TextKit components.
+ *
+ * @param textKitComponents The TextKit stack used to render text.
+ * @param placeholderTextKitComponents The TextKit stack used to render placeholder text.
+ *
+ * @returns An initialized ASEditableTextNode.
+ */
+- (instancetype)initWithTextKitComponents:(ASTextKitComponents *)textKitComponents
+             placeholderTextKitComponents:(ASTextKitComponents *)placeholderTextKitComponents;
+
 //! @abstract The text node's delegate, which must conform to the <ASEditableTextNodeDelegate> protocol.
@property (nonatomic, readwrite, weak) id <ASEditableTextNodeDelegate> delegate;

--- a/AsyncDisplayKit/ASEditableTextNode.mm
+++ b/AsyncDisplayKit/ASEditableTextNode.mm
@@ -12,7 +12,6 @@

 #import "ASDisplayNode+Subclasses.h"
 #import "ASEqualityHelpers.h"
-#import "ASTextKitHelpers.h"
 #import "ASTextNodeWordKerner.h"
 #import "ASThread.h"

@@ -45,6 +44,8 @@
 - (void)setScrollEnabled:(BOOL)scrollEnabled
 {
  _shouldBlockPanGesture = !scrollEnabled;
+  self.scrollsToTop = scrollEnabled;
+
  [super setScrollEnabled:YES];
 }

@@ -93,6 +94,13 @@

 #pragma mark - NSObject Overrides
 - (instancetype)init
+{
+  return [self initWithTextKitComponents:[ASTextKitComponents componentsWithAttributedSeedString:nil textContainerSize:CGSizeZero]
+            placeholderTextKitComponents:[ASTextKitComponents componentsWithAttributedSeedString:nil textContainerSize:CGSizeZero]];
+}
+
+- (instancetype)initWithTextKitComponents:(ASTextKitComponents *)textKitComponents
+             placeholderTextKitComponents:(ASTextKitComponents *)placeholderTextKitComponents
 {
  if (!(self = [super init]))
    return nil;
@@ -101,14 +109,14 @@
  _scrollEnabled = YES;

  // Create the scaffolding for the text view.
-  _textKitComponents = [ASTextKitComponents componentsWithAttributedSeedString:nil textContainerSize:CGSizeZero];
+  _textKitComponents = textKitComponents;
  _textKitComponents.layoutManager.delegate = self;
  _wordKerner = [[ASTextNodeWordKerner alloc] init];
  _returnKeyType = UIReturnKeyDefault;
  _textContainerInset = UIEdgeInsetsZero;
  
  // Create the placeholder scaffolding.
-  _placeholderTextKitComponents = [ASTextKitComponents componentsWithAttributedSeedString:nil textContainerSize:CGSizeZero];
+  _placeholderTextKitComponents = placeholderTextKitComponents;
  _placeholderTextKitComponents.layoutManager.delegate = self;

  return self;
--- a/AsyncDisplayKit/ASTextNode+Beta.h
+++ b/AsyncDisplayKit/ASTextNode+Beta.h
@@ -6,6 +6,7 @@
 //  Copyright © 2016 Facebook. All rights reserved.
 //

+NS_ASSUME_NONNULL_BEGIN

@interface ASTextNode ()

@@ -13,18 +14,19 @@
 @abstract An array of descending scale factors that will be applied to this text node to try to make it fit within its constrained size
 @default nil (no scaling)
 */
-@property (nonatomic, copy) NSArray *pointSizeScaleFactors;
+@property (nullable, nonatomic, copy) NSArray *pointSizeScaleFactors;

 #pragma mark - ASTextKit Customization
 /**
 A block to provide a hook to provide a custom NSLayoutManager to the ASTextKitRenderer
 */
-@property (nonatomic, copy) NSLayoutManager * (^layoutManagerCreationBlock)(void);
+@property (nullable, nonatomic, copy) NSLayoutManager * (^layoutManagerCreationBlock)(void);

 /**
- A block to provide a hook to provide a NSTextStorage to the Text Kit's layout manager.
+ A block to provide a hook to provide a NSTextStorage to the TextKit's layout manager.
 */
-@property (nonatomic, copy) NSTextStorage * (^textStorageCreationBlock)(NSAttributedString *attributedString);
+@property (nullable, nonatomic, copy) NSTextStorage * (^textStorageCreationBlock)(NSAttributedString *_Nullable attributedString);

+@end

-@end
+NS_ASSUME_NONNULL_END
--- a/AsyncDisplayKit/ASTextNode.mm
+++ b/AsyncDisplayKit/ASTextNode.mm
@@ -17,7 +17,7 @@
 #import <AsyncDisplayKit/ASDisplayNodeExtras.h>

 #import "ASTextKitCoreTextAdditions.h"
-#import "ASTextKitHelpers.h"
+#import "ASTextKitComponents.h"
 #import "ASTextKitFontSizeAdjuster.h"
 #import "ASTextKitRenderer.h"
 #import "ASTextKitRenderer+Positioning.h"
@@ -364,6 +364,12 @@ 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
--- a/AsyncDisplayKit/AsyncDisplayKit.h
+++ b/AsyncDisplayKit/AsyncDisplayKit.h
@@ -15,7 +15,6 @@
 #import <AsyncDisplayKit/ASButtonNode.h>
 #import <AsyncDisplayKit/ASMapNode.h>
 #import <AsyncDisplayKit/ASVideoNode.h>
-
 #import <AsyncDisplayKit/ASEditableTextNode.h>

 #import <AsyncDisplayKit/ASBasicImageDownloader.h>
@@ -41,6 +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>
@@ -68,7 +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>
@@ -77,5 +76,8 @@
 #import <AsyncDisplayKit/UICollectionViewLayout+ASConvenience.h>
 #import <AsyncDisplayKit/UIView+ASConvenience.h>
 #import <AsyncDisplayKit/ASRunLoopQueue.h>
+#import <AsyncDisplayKit/ASTextKitComponents.h>

 #import <AsyncDisplayKit/AsyncDisplayKit+Debug.h>
+
+#import <AsyncDisplayKit/ASCollectionNode+Beta.h>
--- a/AsyncDisplayKit/Details/ASDataController.mm
+++ b/AsyncDisplayKit/Details/ASDataController.mm
@@ -129,15 +129,10 @@ static void *kASSizingQueueContext = &kASSizingQueueContext;

 - (void)layoutLoadedNodes:(NSArray<ASCellNode *> *)nodes fromContexts:(NSArray<ASIndexedNodeContext *> *)contexts ofKind:(NSString *)kind
 {
-  NSAssert(NSThread.isMainThread, @"Main thread layout must be on the main thread.");
+  NSAssert(ASDisplayNodeThreadIsMain(), @"Layout of loaded nodes must happen on the main thread.");
  ASDisplayNodeAssertTrue(nodes.count == contexts.count);
  
-  [contexts enumerateObjectsUsingBlock:^(ASIndexedNodeContext *context, NSUInteger idx, __unused BOOL * stop) {
-    ASCellNode *node = nodes[idx];
-    if (node.isNodeLoaded) {
-      [self _layoutNode:node withConstrainedSize:context.constrainedSize];
-    }
-  }];
+  [self _layoutNodes:nodes fromContexts:contexts inIndexesOfRange:NSMakeRange(0, nodes.count) ofKind:kind];
 }

 /**
@@ -160,9 +155,31 @@ static void *kASSizingQueueContext = &kASSizingQueueContext;
  }];
 }

+/**
+ * Perform measurement and layout of loaded or unloaded nodes based if they will be layed out on main thread or not
+ */
+- (void)_layoutNodes:(NSArray<ASCellNode *> *)nodes fromContexts:(NSArray<ASIndexedNodeContext *> *)contexts inIndexesOfRange:(NSRange)range ofKind:(NSString *)kind
+{
+  if (_dataSource == nil) {
+    return;
+  }
+  
+  // For any given layout pass that occurs, this method will be called at least twice, once on the main thread and
+  // the background, to result in complete coverage of both loaded and unloaded nodes
+  BOOL isMainThread = ASDisplayNodeThreadIsMain();
+  for (NSUInteger k = range.location; k < NSMaxRange(range); k++) {
+    ASCellNode *node = nodes[k];
+    // Only nodes that are loaded should be layout on the main thread
+    if (node.isNodeLoaded == isMainThread) {
+      ASIndexedNodeContext *context = contexts[k];
+      [self _layoutNode:node withConstrainedSize:context.constrainedSize];
+    }
+  }
+}
+
 - (void)_layoutNodesFromContexts:(NSArray<ASIndexedNodeContext *> *)contexts ofKind:(NSString *)kind completion:(ASDataControllerCompletionBlock)completionBlock
 {
-  if (!contexts.count) {
+  if (!contexts.count || _dataSource == nil) {
    return;
  }

@@ -200,25 +217,30 @@ static void *kASSizingQueueContext = &kASSizingQueueContext;
        dispatch_semaphore_signal(sema);
      });
      dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
-      [self layoutLoadedNodes:subarray fromContexts:[contexts subarrayWithRange:NSMakeRange(j, batchCount)] ofKind:kind];
+      
+      [self _layoutNodes:subarray
+            fromContexts:contexts
+        inIndexesOfRange:NSMakeRange(0, batchCount)
+                  ofKind:kind];
+      
    } else {
      allocationBlock();
      [_mainSerialQueue performBlockOnMainThread:^{
-        [self layoutLoadedNodes:subarray fromContexts:[contexts subarrayWithRange:NSMakeRange(j, batchCount)] ofKind:kind];
+        [self _layoutNodes:subarray
+              fromContexts:contexts
+          inIndexesOfRange:NSMakeRange(0, batchCount)
+                    ofKind:kind];
      }];
    }

    [allocatedNodes addObjectsFromArray:subarray];

    dispatch_group_async(layoutGroup, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
-      for (NSUInteger k = j; k < j + batchCount; k++) {
-        ASCellNode *node = allocatedNodes[k];
-        // Only measure nodes whose views aren't loaded, since we're in the background.
-        // We should already have measured loaded nodes before we left the main thread, using layoutLoadedNodes:ofKind:atIndexPaths:
-        if (!node.isNodeLoaded) {
-          [self _layoutNode:node withConstrainedSize:contexts[k].constrainedSize];
-        }
-      }
+      // We should already have measured loaded nodes before we left the main thread. Layout the remaining once on a background thread.
+      [self _layoutNodes:allocatedNodes
+            fromContexts:contexts
+        inIndexesOfRange:NSMakeRange(j, batchCount)
+                  ofKind:kind];
    });
  }

@@ -244,7 +266,7 @@ static void *kASSizingQueueContext = &kASSizingQueueContext;

 - (void)insertNodes:(NSArray *)nodes ofKind:(NSString *)kind atIndexPaths:(NSArray *)indexPaths completion:(ASDataControllerCompletionBlock)completionBlock
 {
-  if (indexPaths.count == 0) {
+  if (!indexPaths.count || _dataSource == nil) {
    return;
  }

@@ -265,7 +287,7 @@ static void *kASSizingQueueContext = &kASSizingQueueContext;

 - (void)deleteNodesOfKind:(NSString *)kind atIndexPaths:(NSArray *)indexPaths completion:(ASDataControllerCompletionBlock)completionBlock
 {
-  if (indexPaths.count == 0) {
+  if (!indexPaths.count || _dataSource == nil) {
    return;
  }

@@ -285,8 +307,9 @@ static void *kASSizingQueueContext = &kASSizingQueueContext;

 - (void)insertSections:(NSMutableArray *)sections ofKind:(NSString *)kind atIndexSet:(NSIndexSet *)indexSet completion:(void (^)(NSArray *sections, NSIndexSet *indexSet))completionBlock
 {
-  if (indexSet.count == 0)
+  if (!indexSet.count|| _dataSource == nil) {
    return;
+  }

  if (_editingNodes[kind] == nil) {
    _editingNodes[kind] = [NSMutableArray array];
@@ -307,8 +330,10 @@ static void *kASSizingQueueContext = &kASSizingQueueContext;

 - (void)deleteSectionsOfKind:(NSString *)kind atIndexSet:(NSIndexSet *)indexSet completion:(void (^)(NSIndexSet *indexSet))completionBlock
 {
-  if (indexSet.count == 0)
+  if (!indexSet.count || _dataSource == nil) {
    return;
+  }
+  
  [_editingNodes[kind] removeObjectsAtIndexes:indexSet];
  [_mainSerialQueue performBlockOnMainThread:^{
    [_completedNodes[kind] removeObjectsAtIndexes:indexSet];
@@ -328,9 +353,6 @@ static void *kASSizingQueueContext = &kASSizingQueueContext;
 */
 - (void)_insertNodes:(NSArray *)nodes atIndexPaths:(NSArray *)indexPaths withAnimationOptions:(ASDataControllerAnimationOptions)animationOptions
 {
-  if (indexPaths.count == 0) {
-    return;
-  }
  [self insertNodes:nodes ofKind:ASDataControllerRowNodeKind atIndexPaths:indexPaths completion:^(NSArray *nodes, NSArray *indexPaths) {
    if (_delegateDidInsertNodes)
      [_delegate dataController:self didInsertNodes:nodes atIndexPaths:indexPaths withAnimationOptions:animationOptions];
@@ -345,9 +367,6 @@ static void *kASSizingQueueContext = &kASSizingQueueContext;
 */
 - (void)_deleteNodesAtIndexPaths:(NSArray *)indexPaths withAnimationOptions:(ASDataControllerAnimationOptions)animationOptions
 {
-  if (indexPaths.count == 0) {
-    return;
-  }
  [self deleteNodesOfKind:ASDataControllerRowNodeKind atIndexPaths:indexPaths completion:^(NSArray *nodes, NSArray *indexPaths) {
    if (_delegateDidDeleteNodes)
      [_delegate dataController:self didDeleteNodes:nodes atIndexPaths:indexPaths withAnimationOptions:animationOptions];
--- a/AsyncDisplayKit/Details/ASEnvironment.h
+++ b/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
--- a/AsyncDisplayKit/Details/ASEnvironment.m
+++ b/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()
+  };
+}
--- a/AsyncDisplayKit/Layout/ASLayoutOptions.h
+++ b/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
-
--- a/AsyncDisplayKit/Layout/ASLayoutOptions.mm
+++ b/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
--- a/AsyncDisplayKit/Layout/ASLayoutOptionsPrivate.mm
+++ b/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
--- a/AsyncDisplayKit/Layout/ASLayoutSpec.h
+++ b/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.
 *
--- a/AsyncDisplayKit/Layout/ASLayoutSpec.mm
+++ b/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, but don't override customized values.
+      ASEnvironmentStatePropagateUp(finalLayoutable, child.environmentState.layoutOptionsState);
      return finalLayoutable;
    }
  }
@@ -90,6 +97,16 @@ static NSString * const kDefaultChildrenKey = @"kDefaultChildrenKey";
  return _layoutChildren;
 }

+- (void)setParent:(id<ASLayoutable>)parent
+{
+  // FIXME: Locking should be evaluated here.  _parent is not widely used yet, though.
+  _parent = parent;
+  
+  if ([parent supportsUpwardPropagation]) {
+    ASEnvironmentStatePropagateUp(parent, self.environmentState.layoutOptionsState);
+  }
+}
+
 - (void)setChild:(id<ASLayoutable>)child;
 {
  [self setChild:child forIdentifier:kDefaultChildKey];
@@ -98,7 +115,13 @@ 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];
+  self.layoutChildren[identifier] = finalLayoutable;
+  if ([finalLayoutable isKindOfClass:[ASLayoutSpec class]]) {
+    [(ASLayoutSpec *)finalLayoutable setParent:self]; // This will trigger upward propogation if needed.
+  } else if ([self supportsUpwardPropagation]) {
+    ASEnvironmentStatePropagateUp(self, finalLayoutable.environmentState.layoutOptionsState); // Probably an ASDisplayNode
+  }
 }

 - (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)
--- a/AsyncDisplayKit/Layout/ASLayoutable.h
+++ b/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.
--- a/AsyncDisplayKit/Layout/ASLayoutable.mm
+++ b/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>
--- a/AsyncDisplayKit/Layout/ASLayoutableExtensibility.h
+++ b/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
--- a/AsyncDisplayKit/Layout/ASLayoutablePrivate.h
+++ b/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);\
+}\
--- a/AsyncDisplayKit/Layout/ASStackLayoutSpec.mm
+++ b/AsyncDisplayKit/Layout/ASStackLayoutSpec.mm
@@ -198,6 +198,15 @@

@end

+@implementation ASStackLayoutSpec (ASEnvironment)
+
+- (BOOL)supportsUpwardPropagation
+{
+  return NO;
+}
+
+@end
+
@implementation ASStackLayoutSpec (Debugging)

 #pragma mark - ASLayoutableAsciiArtProtocol
--- a/AsyncDisplayKit/Layout/ASStaticLayoutSpec.mm
+++ b/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
--- a/AsyncDisplayKit/Private/ASDisplayNode+FrameworkPrivate.h
+++ b/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
--- a/AsyncDisplayKit/Private/ASDisplayNodeInternal.h
+++ b/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;
--- a/AsyncDisplayKit/Private/ASEnvironmentInternal.h
+++ b/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);
+  }
+}
--- a/AsyncDisplayKit/Private/ASEnvironmentInternal.mm
+++ b/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 = state.alignSelf;
+    }
+    if (parentState.flexGrow == defaultState.flexGrow) {
+      parentState.flexGrow = state.flexGrow;
+    }
+    if (ASRelativeDimensionEqualToRelativeDimension(parentState.flexBasis, defaultState.flexBasis)) {
+      parentState.flexBasis = state.flexBasis;
+    }
+    if (parentState.alignSelf == defaultState.alignSelf) {
+      parentState.alignSelf = state.alignSelf;
+    }
+    if (parentState.ascender == defaultState.ascender) {
+      parentState.ascender = state.ascender;
+    }
+    
+    if (ASRelativeSizeRangeEqualToRelativeSizeRange(parentState.sizeRange, defaultState.sizeRange)) {
+      parentState.sizeRange = state.sizeRange;
+    }
+    if (CGPointEqualToPoint(parentState.layoutPosition, defaultState.layoutPosition)) {
+      parentState.layoutPosition = state.layoutPosition;
+    }
+    
+    environmentState.layoutOptionsState = parentState;
+  }
+  
+  return environmentState;
+}
--- a/AsyncDisplayKit/Private/ASLayoutOptionsPrivate.h
+++ b/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
--- a/AsyncDisplayKit/Private/ASStackBaselinePositionedLayout.mm
+++ b/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) {
--- a/AsyncDisplayKit/Private/ASStackPositionedLayout.mm
+++ b/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,
--- a/AsyncDisplayKit/Private/ASStackUnpositionedLayout.mm
+++ b/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 + layoutOptions.spacingBefore + layoutOptions.spacingAfter;
+                                                    return x + child.spacingBefore + child.spacingAfter;
                                                  });

  // Sum up the childrens' dimensions (including spacing) in the stack direction.
--- a/AsyncDisplayKit/TextKit/ASTextKitComponents.h
+++ b/AsyncDisplayKit/TextKit/ASTextKitComponents.h
@@ -6,11 +6,8 @@
 * of patent rights can be found in the PATENTS file in the same directory.
 */

-#import <objc/message.h>
-
-#import <Foundation/Foundation.h>
 #import <UIKit/UIKit.h>
-#import "ASBaseDefines.h"
+#import <AsyncDisplayKit/ASBaseDefines.h>

 NS_ASSUME_NONNULL_BEGIN

@@ -37,8 +34,20 @@ ASDISPLAYNODE_INLINE CGSize ceilSizeValue(CGSize s)
 @return An `ASTextKitComponents` containing the created components. The text view component will be nil.
 @discussion The returned components will be hooked up together, so they are ready for use as a system upon return.
 */
-+ (ASTextKitComponents *)componentsWithAttributedSeedString:(nullable NSAttributedString *)attributedSeedString
-                                          textContainerSize:(CGSize)textContainerSize;
+ (instancetype)componentsWithAttributedSeedString:(nullable NSAttributedString *)attributedSeedString
+                                 textContainerSize:(CGSize)textContainerSize;
+
+/**
+ @abstract Creates the stack of TextKit components.
+ @param textStorage The NSTextStorage to use.
+ @param textContainerSize The size of the text-container. Typically, size specifies the constraining width of the layout, and FLT_MAX for height. Pass CGSizeZero if these components will be hooked up to a UITextView, which will manage the text container's size itself.
+ @param layoutManager The NSLayoutManager to use.
+ @return An `ASTextKitComponents` containing the created components. The text view component will be nil.
+ @discussion The returned components will be hooked up together, so they are ready for use as a system upon return.
+ */
+ (instancetype)componentsWithTextStorage:(NSTextStorage *)textStorage
+                        textContainerSize:(CGSize)textContainerSize
+                            layoutManager:(NSLayoutManager *)layoutManager;

 /**
 @abstract Returns the bounding size for the text view's text.
--- a/AsyncDisplayKit/TextKit/ASTextKitComponents.m
+++ b/AsyncDisplayKit/TextKit/ASTextKitComponents.m
@@ -6,7 +6,7 @@
 * of patent rights can be found in the PATENTS file in the same directory.
 */

-#import "ASTextKitHelpers.h"
+#import "ASTextKitComponents.h"

@interface ASTextKitComponents ()

@@ -19,15 +19,25 @@

@implementation ASTextKitComponents

-+ (ASTextKitComponents *)componentsWithAttributedSeedString:(NSAttributedString *)attributedSeedString
-                                          textContainerSize:(CGSize)textContainerSize
+ (instancetype)componentsWithAttributedSeedString:(NSAttributedString *)attributedSeedString
+                                 textContainerSize:(CGSize)textContainerSize
 {
-  ASTextKitComponents *components = [[ASTextKitComponents alloc] init];
+  NSTextStorage *textStorage = attributedSeedString ? [[NSTextStorage alloc] initWithAttributedString:attributedSeedString] : [[NSTextStorage alloc] init];

-  // Create the TextKit component stack with our default configuration.
-  components.textStorage = (attributedSeedString ? [[NSTextStorage alloc] initWithAttributedString:attributedSeedString] : [[NSTextStorage alloc] init]);
+  return [self componentsWithTextStorage:textStorage
+                       textContainerSize:textContainerSize
+                           layoutManager:[[NSLayoutManager alloc] init]];
+}

-  components.layoutManager = [[NSLayoutManager alloc] init];
+ (instancetype)componentsWithTextStorage:(NSTextStorage *)textStorage
+                        textContainerSize:(CGSize)textContainerSize
+                            layoutManager:(NSLayoutManager *)layoutManager
+{
+  ASTextKitComponents *components = [[self alloc] init];
+
+  components.textStorage = textStorage;
+
+  components.layoutManager = layoutManager;
  [components.textStorage addLayoutManager:components.layoutManager];

  components.textContainer = [[NSTextContainer alloc] initWithSize:textContainerSize];
--- a/AsyncDisplayKitTests/ASCenterLayoutSpecSnapshotTests.mm
+++ b/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}};

--- a/AsyncDisplayKitTests/ASRelativeLayoutSpecSnapshotTests.mm
+++ b/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}};

--- a/AsyncDisplayKitTests/ASStackLayoutSpecSnapshotTests.mm
+++ b/AsyncDisplayKitTests/ASStackLayoutSpecSnapshotTests.mm
@@ -15,7 +15,6 @@
 #import "ASBackgroundLayoutSpec.h"
 #import "ASRatioLayoutSpec.h"
 #import "ASInsetLayoutSpec.h"
-#import "ASLayoutOptions.h"

@interface ASStackLayoutSpecSnapshotTests : ASLayoutSpecSnapshotTestCase
@end
--- a/AsyncDisplayKitTests/ASTextNodeWordKernerTests.mm
+++ b/AsyncDisplayKitTests/ASTextNodeWordKernerTests.mm
@@ -8,7 +8,7 @@

 #import <XCTest/XCTest.h>

-#import "ASTextKitHelpers.h"
+#import "ASTextKitComponents.h"
 #import "ASTextNodeTypes.h"
 #import "ASTextNodeWordKerner.h"

--- a/README.md
+++ b/README.md
@@ -4,8 +4,9 @@
 [![Coverage Status](https://coveralls.io/repos/facebook/AsyncDisplayKit/badge.svg?branch=master)](https://coveralls.io/r/facebook/AsyncDisplayKit?branch=master)
 [![Version](https://img.shields.io/cocoapods/v/AsyncDisplayKit.svg)](http://cocoapods.org/pods/AsyncDisplayKit)
 [![Platform](https://img.shields.io/cocoapods/p/AsyncDisplayKit.svg)]()
+[![Carthage compatible](https://img.shields.io/badge/Carthage-compatible-4BC51D.svg?style=flat)](https://github.com/Carthage/Carthage)
 [![License](https://img.shields.io/cocoapods/l/AsyncDisplayKit.svg)](https://github.com/facebook/AsyncDisplayKit/blob/master/LICENSE)
-[![Downloads](https://img.shields.io/badge/downloads-%3E120k-green.svg)](http://cocoapods.org/pods/AsyncDisplayKit)
+[![Downloads](https://img.shields.io/badge/downloads-%3E320k-green.svg)](http://cocoapods.org/pods/AsyncDisplayKit)

 AsyncDisplayKit is an iOS framework that keeps even the most complex user
 interfaces smooth and responsive.  It was originally built to make Facebook's
--- a/build.sh
+++ b/build.sh
@@ -1,8 +1,8 @@
 #!/bin/bash

 # **** Update me when new Xcode versions are released! ****
-PLATFORM="platform=iOS Simulator,OS=9.2,name=iPhone 6"
-SDK="iphonesimulator9.2"
+PLATFORM="platform=iOS Simulator,OS=9.3,name=iPhone 6"
+SDK="iphonesimulator9.3"


 # It is pitch black.
--- a/examples/EditableText/CustomCollectionView.gif
+++ b/examples/EditableText/CustomCollectionView.gif
--- a/examples/README.md
+++ b/examples/README.md
@@ -5,6 +5,178 @@
 Run `pod install` in each sample project directory to set up their
 dependencies.

+## Example Catalog
+
+### ASCollectionView [ObjC]
+
+![ASCollectionView Example App Screenshot](./Screenshots/ASCollectionView.png?raw=true)
+ 
+Featuring:
+- ASCollectionView with header/footer supplementary node support
+- ASCollectionView batch API
+- ASDelegateProxy
+
+### ASTableViewStressTest [ObjC]
+
+![ASTableViewStressTest Example App Screenshot](./Screenshots/ASTableViewStressTest.png?raw=true)
+
+### ASViewController [ObjC]
+
+![ASViewController Example App Screenshot](./Screenshots/ASViewController.png?raw=true)
+ 
+Featuring:
+- ASViewController
+- ASTableView
+- ASMultiplexImageNode
+- ASLayoutSpec
+
+### BackgroundPropertySetting [Swift]
+
+![BackgroundPropertySetting Example App gif](./Screenshots/BackgroundPropertySetting.gif?raw=true)
+ 
+Featuring:
+- ASDK Swift compatibility
+- ASViewController
+- ASCollectionView
+- thread affinity
+- ASLayoutSpec
+
+### CarthageBuildTest
+### CatDealsCollectionView [ObjC]
+
+![CatDealsCollectionView Example App Screenshot](./Screenshots/CatDealsCollectionView.png?raw=true)
+ 
+Featuring:
+- ASCollectionView
+- ASRangeTuningParameters
+- Placeholder Images
+- ASLayoutSpec
+
+### CollectionViewWithViewControllerCells [ObjC]
+
+![CollectionViewWithViewControllerCells Example App Screenshot](./Screenshots/CollectionViewWithViewControllerCells.png?raw=true)
+ 
+Featuring:
+- custom collection view layout
+- ASLayoutSpec
+- ASMultiplexImageNode
+
+### CustomCollectionView [ObjC]
+
+![CustomCollectionView Example App gif](./Screenshots/CustomCollectionView.gif?raw=true)
+ 
+Featuring:
+- custom collection view layout
+- ASCollectionView with sections
+
+### EditableText [ObjC]
+
+![EditableText Example App Screenshot](./Screenshots/EditableText.png?raw=true)
+ 
+Featuring:
+- ASEditableTextNode
+
+### HorizontalwithinVerticalScrolling [ObjC]
+
+![HorizontalwithinVerticalScrolling Example App gif](./Screenshots/HorizontalwithinVerticalScrolling.gif?raw=true)
+ 
+Featuring:
+- UIViewController with ASTableView
+- ASCollectionView
+- ASCellNode
+
+### Kittens [ObjC]
+
+![Kittens Example App Screenshot](./Screenshots/Kittens.png?raw=true)
+ 
+Featuring:
+- UIViewController with ASTableView
+- ASCellNodes with ASNetworkImageNode and ASTextNode
+
+### Multiplex [ObjC]
+
+![Multiplex Example App gif](./Screenshots/Multiplex.gif?raw=true)
+ 
+Featuring:
+- ASMultiplexImageNode (with artificial delay inserted)
+- ASLayoutSpec
+
+### PagerNode [ObjC]
+
+Featuring:
+- ASPagerNode
+
+### Placeholders [ObjC]
+
+Featuring:
+- ASDisplayNodes now have an overidable method -placeholderImage that lets you provide a custom UIImage to display while a node is displaying asyncronously. The default implementation of this method returns nil and thus does nothing. A provided example project also demonstrates using the placeholder API.
+
+### SocialAppLayout [ObjC]
+
+![SocialAppLayout Example App Screenshot](./Screenshots/SocialAppLayout.png?raw=true)
+
+Featuring:
+- ASLayoutSpec
+- UIViewController with ASTableView
+
+### Swift [Swift]
+
+![Swift Example App Screenshot](./Screenshots/Swift.png?raw=true)
+
+Featuring:
+- ASViewController with ASTableNode
+
+### SynchronousConcurrency [ObjC]
+
+![SynchronousConcurrency Example App Screenshot](./Screenshots/SynchronousConcurrency.png?raw=true)
+
+Implementation of Synchronous Concurrency features for AsyncDisplayKit 2.0
+
+This provides internal features on _ASAsyncTransaction and ASDisplayNode to facilitate
+implementing public API that allows clients to choose if they would prefer to block
+on the completion of unfinished rendering, rather than allow a placeholder state to
+become visible.
+
+The internal features are:
+-[_ASAsyncTransaction waitUntilComplete]
+-[ASDisplayNode recursivelyEnsureDisplay]
+
+Also provided are two such implementations:
+-[ASCellNode setNeverShowPlaceholders:], which integrates with both Tables and Collections
+-[ASViewController setNeverShowPlaceholders:], which should work with Nav and Tab controllers.
+
+Lastly, on ASDisplayNode, a new property .shouldBypassEnsureDisplay allows individual node types
+to exempt themselves from blocking the main thread on their display.
+
+By implementing the feature at the ASCellNode level rather than ASTableView & ASCollectionView,
+developers can retain fine-grained control on display characteristics.  For example, certain
+cell types may be appropriate to display to the user with placeholders, whereas others may not.
+
+### SynchronousKittens [ObjC]
+
+### VerticalWithinHorizontalScrolling [ObjC]
+
+![VerticalWithinHorizontalScrolling Example App Screenshot](./Screenshots/VerticalWithinHorizontalScrolling.png?raw=true)
+
+Features:
+- UIViewController containing ASPagerNode containing ASTableNodes
+
+### Videos [ObjC]
+
+![VideoTableView Example App gif](./Screenshots/Videos.gif?raw=true)
+
+Featuring:
+- ASVideoNode
+
+### VideoTableView [ObjC]
+
+![VideoTableView Example App Screenshot](./Screenshots/VideoTableView.png?raw=true) 
+
+Featuring:
+- ASVideoNode
+- ASTableView
+- ASCellNode
+
 ## License

    This file provided by Facebook is for non-commercial testing and evaluation
--- a/examples/Screenshots/ASCollectionView.png
+++ b/examples/Screenshots/ASCollectionView.png
--- a/examples/Screenshots/ASTableViewStressTest.png
+++ b/examples/Screenshots/ASTableViewStressTest.png
--- a/examples/Screenshots/ASViewController.png
+++ b/examples/Screenshots/ASViewController.png
--- a/examples/Screenshots/BackgroundPropertySetting.gif
+++ b/examples/Screenshots/BackgroundPropertySetting.gif
--- a/examples/Screenshots/CatDealsCollectionView.png
+++ b/examples/Screenshots/CatDealsCollectionView.png
--- a/examples/Screenshots/CollectionViewWithViewControllerCells.png
+++ b/examples/Screenshots/CollectionViewWithViewControllerCells.png
--- a/examples/Screenshots/CustomCollectionView.gif
+++ b/examples/Screenshots/CustomCollectionView.gif
--- a/examples/Screenshots/EditableText.png
+++ b/examples/Screenshots/EditableText.png
--- a/examples/Screenshots/HorizontalwithinVerticalScrolling.gif
+++ b/examples/Screenshots/HorizontalwithinVerticalScrolling.gif
--- a/examples/Screenshots/Kittens.png
+++ b/examples/Screenshots/Kittens.png
--- a/examples/Screenshots/Multiplex.gif
+++ b/examples/Screenshots/Multiplex.gif
--- a/examples/Screenshots/SocialAppLayout.png
+++ b/examples/Screenshots/SocialAppLayout.png
--- a/examples/Screenshots/Swift.png
+++ b/examples/Screenshots/Swift.png
--- a/examples/Screenshots/SynchronousConcurrency.png
+++ b/examples/Screenshots/SynchronousConcurrency.png
--- a/examples/Screenshots/VerticalWithinHorizontalScrolling.gif
+++ b/examples/Screenshots/VerticalWithinHorizontalScrolling.gif
--- a/examples/Screenshots/VideoTableView.png
+++ b/examples/Screenshots/VideoTableView.png
--- a/examples/Screenshots/Videos.gif
+++ b/examples/Screenshots/Videos.gif
--- a/examples/SocialAppLayout/Sample/AppDelegate.h
+++ b/examples/SocialAppLayout/Sample/AppDelegate.h
@@ -15,6 +15,4 @@

@property (strong, nonatomic) UIWindow *window;

-
@end
-
--- a/examples/SocialAppLayout/Sample/AppDelegate.m
+++ b/examples/SocialAppLayout/Sample/AppDelegate.m
@@ -10,23 +10,17 @@
 */

 #import "AppDelegate.h"
-
 #import "ViewController.h"

-@interface AppDelegate ()
-
-@end
-
@implementation AppDelegate

-
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
+- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
+{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.window.backgroundColor = [UIColor whiteColor];
    self.window.rootViewController = [[UINavigationController alloc] initWithRootViewController:[[ViewController alloc] init]];
    [self.window makeKeyAndVisible];
    return YES;
-
 }

@end
--- a/examples/SocialAppLayout/Sample/CommentsNode.m
+++ b/examples/SocialAppLayout/Sample/CommentsNode.m
@@ -20,8 +20,8 @@

@implementation CommentsNode

- (instancetype)initWithCommentsCount:(NSInteger)comentsCount {
-    
+- (instancetype)initWithCommentsCount:(NSInteger)comentsCount
+{
    self = [super init];
    if (self) {
        _commentsCount = comentsCount;
@@ -44,8 +44,8 @@
    
 }

- (ASLayoutSpec *)layoutSpecThatFits:(ASSizeRange)constrainedSize {
-    
+- (ASLayoutSpec *)layoutSpecThatFits:(ASSizeRange)constrainedSize
+{
    ASStackLayoutSpec *mainStack =  [ASStackLayoutSpec stackLayoutSpecWithDirection:ASStackLayoutDirectionHorizontal spacing:6.0 justifyContent:ASStackLayoutJustifyContentStart alignItems:ASStackLayoutAlignItemsCenter children:@[self.iconNode, self.countNode]];
    
    // set sizeRange to make width fixed to 60
@@ -55,5 +55,4 @@
    return [ASStaticLayoutSpec staticLayoutSpecWithChildren:@[mainStack]];
 }

-
@end
--- a/examples/SocialAppLayout/Sample/LikesNode.m
+++ b/examples/SocialAppLayout/Sample/LikesNode.m
@@ -21,8 +21,8 @@

@implementation LikesNode

- (instancetype)initWithLikesCount:(NSInteger)likesCount {
-    
+- (instancetype)initWithLikesCount:(NSInteger)likesCount
+{
    self = [super init];
    if (self) {
        _likesCount = likesCount;
@@ -49,7 +49,7 @@
    
 }

-+ (BOOL) getYesOrNo
+ (BOOL)getYesOrNo
 {
    int tmp = (arc4random() % 30)+1;
    if (tmp % 5 == 0) {
@@ -58,8 +58,8 @@
    return NO;
 }

- (ASLayoutSpec *)layoutSpecThatFits:(ASSizeRange)constrainedSize {
-    
+- (ASLayoutSpec *)layoutSpecThatFits:(ASSizeRange)constrainedSize
+{
    ASStackLayoutSpec *mainStack = [ASStackLayoutSpec stackLayoutSpecWithDirection:ASStackLayoutDirectionHorizontal spacing:6.0 justifyContent:ASStackLayoutJustifyContentStart alignItems:ASStackLayoutAlignItemsCenter children:@[_iconNode, _countNode]];
    
    // set sizeRange to make width fixed to 60
@@ -67,7 +67,6 @@
    ASRelativeSize max = ASRelativeSizeMake(ASRelativeDimensionMakeWithPoints(60.0), ASRelativeDimensionMakeWithPoints(40.0));
    mainStack.sizeRange = ASRelativeSizeRangeMake(min, max);
    return [ASStaticLayoutSpec staticLayoutSpecWithChildren:@[mainStack]];
-    
 }

@end
--- a/examples/SocialAppLayout/Sample/Post.m
+++ b/examples/SocialAppLayout/Sample/Post.m
@@ -12,5 +12,4 @@
 #import "Post.h"

@implementation Post
-
@end
--- a/examples/SocialAppLayout/Sample/PostNode.m
+++ b/examples/SocialAppLayout/Sample/PostNode.m
@@ -34,8 +34,8 @@

@implementation PostNode

- (instancetype)initWithPost:(Post *)post {
-    
+- (instancetype)initWithPost:(Post *)post
+{
    self = [super init];
    if (self) {
        _post = post;
@@ -181,14 +181,19 @@
    [super didLoad];
 }

- (ASLayoutSpec *)layoutSpecThatFits:(ASSizeRange)constrainedSize {
-    
+- (ASLayoutSpec *)layoutSpecThatFits:(ASSizeRange)constrainedSize
+{
    // Flexible spacer between username and time
    ASLayoutSpec *spacer = [[ASLayoutSpec alloc] init];
    spacer.flexGrow = YES;
-    
+  
+    // NOTE: This inset is not actually required by the layout, but is an example of the upward propogation of layoutable
+    // properties.  Specifically, .flexGrow from the child is transferred to the inset spec so they can expand together.
+    // Without this capability, it would be required to set insetSpacer.flexGrow = YES;
+    ASInsetLayoutSpec *insetSpacer = [ASInsetLayoutSpec insetLayoutSpecWithInsets:UIEdgeInsetsMake(0, 0, 0, 0) child:spacer];
+  
    // Horizontal stack for name, username, via icon and time
-    NSMutableArray *layoutSpecChildren = [@[_nameNode, _usernameNode, spacer] mutableCopy];
+    NSMutableArray *layoutSpecChildren = [@[_nameNode, _usernameNode, insetSpacer] mutableCopy];
    if (_post.via != 0) {
        [layoutSpecChildren addObject:_viaNode];
    }
--- a/examples/SocialAppLayout/Sample/TextStyles.m
+++ b/examples/SocialAppLayout/Sample/TextStyles.m
@@ -54,16 +54,16 @@
    };
 }

-+ (NSDictionary *)cellControlStyle {
-    
+ (NSDictionary *)cellControlStyle
+{
    return @{
        NSFontAttributeName : [UIFont systemFontOfSize:13.0],
        NSForegroundColorAttributeName: [UIColor lightGrayColor]
    };
 }

-+ (NSDictionary *)cellControlColoredStyle {
-    
+ (NSDictionary *)cellControlColoredStyle
+{
    return @{
        NSFontAttributeName : [UIFont systemFontOfSize:13.0],
        NSForegroundColorAttributeName: [UIColor colorWithRed:59.0/255.0 green:89.0/255.0 blue:152.0/255.0 alpha:1.0]
--- a/examples/SocialAppLayout/Sample/ViewController.h
+++ b/examples/SocialAppLayout/Sample/ViewController.h
@@ -12,7 +12,4 @@
 #import <UIKit/UIKit.h>

@interface ViewController : UIViewController
-
-
@end
-
--- a/examples/SocialAppLayout/Sample/ViewController.m
+++ b/examples/SocialAppLayout/Sample/ViewController.m
@@ -45,8 +45,8 @@
    _tableView.asyncDelegate = nil;
 }

- (void)viewDidLoad {
-    
+- (void)viewDidLoad
+{
    [super viewDidLoad];
    
    self.tableView = [[ASTableView alloc] initWithFrame:self.view.bounds style:UITableViewStylePlain asyncDataFetching:YES];
@@ -57,8 +57,8 @@
    [self.view addSubview:self.tableView];
 }

- (void)createSocialAppDataSource {
-    
+- (void)createSocialAppDataSource
+{
    _socialAppDataSource = [[NSMutableArray alloc] init];
    
    Post *newPost = [[Post alloc] init];