Introduce ASSectionContext and ASSection (facebookarchive#2178)

- Objects conform to ASSectionContext protocol can be provided via ASCollectionDataSource and later retrieved from the collection view. They are guaranteed to be in sync with sections of the collection view. They can be used to store additional data associated with each section, to be used in collection view layout and the like. - ASSection is an internal object that is the foundation for coming debugging tools. - Unit tests included.
sainttail · Oct 1, 2016 · 066351b · 066351b
1 parent 3f42fcb
commit 066351b
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Showing 15 changed files with 310 additions and 105 deletions.
diff --git a/AsyncDisplayKit.xcodeproj/project.pbxproj b/AsyncDisplayKit.xcodeproj/project.pbxproj
@@ -300,8 +300,13 @@
  AC3C4A521A1139C100143C57 /* ASCollectionView.mm in Sources */ = {isa = PBXBuildFile; fileRef = AC3C4A501A1139C100143C57 /* ASCollectionView.mm */; };
  AC47D9421B3B891B00AAEE9D /* ASCellNode.mm in Sources */ = {isa = PBXBuildFile; fileRef = AC6456071B0A335000CF11B8 /* ASCellNode.mm */; };
  AC47D9461B3BB41900AAEE9D /* ASRelativeSize.mm in Sources */ = {isa = PBXBuildFile; fileRef = AC47D9441B3BB41900AAEE9D /* ASRelativeSize.mm */; };
+ AC6145411D8AFAE8003D62A2 /* ASSection.h in Headers */ = {isa = PBXBuildFile; fileRef = AC6145401D8AFAE8003D62A2 /* ASSection.h */; };
+ AC6145431D8AFD4F003D62A2 /* ASSection.m in Sources */ = {isa = PBXBuildFile; fileRef = AC6145421D8AFD4F003D62A2 /* ASSection.m */; };
+ AC6145441D8AFD4F003D62A2 /* ASSection.m in Sources */ = {isa = PBXBuildFile; fileRef = AC6145421D8AFD4F003D62A2 /* ASSection.m */; };
  AC6456091B0A335000CF11B8 /* ASCellNode.mm in Sources */ = {isa = PBXBuildFile; fileRef = AC6456071B0A335000CF11B8 /* ASCellNode.mm */; };
  AC7A2C181BDE11DF0093FE1A /* ASTableViewInternal.h in Headers */ = {isa = PBXBuildFile; fileRef = AC7A2C161BDE11DF0093FE1A /* ASTableViewInternal.h */; };
+ ACE87A2C1D73696800D7FF06 /* ASSectionContext.h in Headers */ = {isa = PBXBuildFile; fileRef = ACE87A2B1D73696800D7FF06 /* ASSectionContext.h */; settings = {ATTRIBUTES = (Public, ); }; };
+ ACE87A331D73726300D7FF06 /* ASSectionContext.h in CopyFiles */ = {isa = PBXBuildFile; fileRef = ACE87A2B1D73696800D7FF06 /* ASSectionContext.h */; };
  ACF6ED1B1B17843500DA7C62 /* ASBackgroundLayoutSpec.mm in Sources */ = {isa = PBXBuildFile; fileRef = ACF6ED021B17843500DA7C62 /* ASBackgroundLayoutSpec.mm */; };
  ACF6ED1D1B17843500DA7C62 /* ASCenterLayoutSpec.mm in Sources */ = {isa = PBXBuildFile; fileRef = ACF6ED041B17843500DA7C62 /* ASCenterLayoutSpec.mm */; };
  ACF6ED211B17843500DA7C62 /* ASDimension.mm in Sources */ = {isa = PBXBuildFile; fileRef = ACF6ED081B17843500DA7C62 /* ASDimension.mm */; };
@@ -653,6 +658,7 @@
  files = (
  CC4C2A7A1D8902350039ACAB /* ASTraceEvent.h in CopyFiles */,
  CC88F7AE1D80AF5E000D6D4E /* ASObjectDescriptionHelpers.h in CopyFiles */,
+ ACE87A331D73726300D7FF06 /* ASSectionContext.h in CopyFiles */,
  F7CE6C981D2CDB5800BE4C15 /* ASInternalHelpers.h in CopyFiles */,
  F7CE6CB71D2CE2D000BE4C15 /* ASLayoutElementExtensibility.h in CopyFiles */,
  F7CE6C131D2CDB3E00BE4C15 /* ASPagerFlowLayout.h in CopyFiles */,
@@ -1052,9 +1058,12 @@
  AC3C4A531A113EEC00143C57 /* ASCollectionViewProtocols.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASCollectionViewProtocols.h; sourceTree = "<group>"; };
  AC47D9431B3BB41900AAEE9D /* ASRelativeSize.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASRelativeSize.h; path = AsyncDisplayKit/Layout/ASRelativeSize.h; sourceTree = "<group>"; };
  AC47D9441B3BB41900AAEE9D /* ASRelativeSize.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; name = ASRelativeSize.mm; path = AsyncDisplayKit/Layout/ASRelativeSize.mm; sourceTree = "<group>"; };
+ AC6145401D8AFAE8003D62A2 /* ASSection.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASSection.h; path = ../Private/ASSection.h; sourceTree = "<group>"; };
+ AC6145421D8AFD4F003D62A2 /* ASSection.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = ASSection.m; path = ../Private/ASSection.m; sourceTree = "<group>"; };
  AC6456071B0A335000CF11B8 /* ASCellNode.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASCellNode.mm; sourceTree = "<group>"; };
  AC7A2C161BDE11DF0093FE1A /* ASTableViewInternal.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASTableViewInternal.h; sourceTree = "<group>"; };
  ACC945A81BA9E7A0005E1FB8 /* ASViewController.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASViewController.h; sourceTree = "<group>"; };
+ ACE87A2B1D73696800D7FF06 /* ASSectionContext.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASSectionContext.h; path = Details/ASSectionContext.h; sourceTree = "<group>"; };
  ACF6ED011B17843500DA7C62 /* ASBackgroundLayoutSpec.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASBackgroundLayoutSpec.h; path = AsyncDisplayKit/Layout/ASBackgroundLayoutSpec.h; sourceTree = "<group>"; };
  ACF6ED021B17843500DA7C62 /* ASBackgroundLayoutSpec.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; lineEnding = 0; name = ASBackgroundLayoutSpec.mm; path = AsyncDisplayKit/Layout/ASBackgroundLayoutSpec.mm; sourceTree = "<group>"; };
  ACF6ED031B17843500DA7C62 /* ASCenterLayoutSpec.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ASCenterLayoutSpec.h; path = AsyncDisplayKit/Layout/ASCenterLayoutSpec.h; sourceTree = "<group>"; };
@@ -1320,6 +1329,7 @@
  25E327551C16819500A2170C /* ASPagerNode.m */,
  A2763D771CBDD57D00A9ADBD /* ASPINRemoteImageDownloader.h */,
  A2763D781CBDD57D00A9ADBD /* ASPINRemoteImageDownloader.m */,
+ ACE87A2B1D73696800D7FF06 /* ASSectionContext.h */,
  D785F6601A74327E00291744 /* ASScrollNode.h */,
  D785F6611A74327E00291744 /* ASScrollNode.m */,
  68FC85E01CE29B7E00EDD713 /* ASTabBarController.h */,
@@ -1648,6 +1658,8 @@
  AC026B681BD57D6F00BBC17E /* ASChangeSetDataController.mm */,
  E5711A2A1C840C81009619D4 /* ASIndexedNodeContext.h */,
  E5711A2D1C840C96009619D4 /* ASIndexedNodeContext.mm */,
+ AC6145401D8AFAE8003D62A2 /* ASSection.h */,
+ AC6145421D8AFD4F003D62A2 /* ASSection.m */,
  );
  name = "Data Controller";
  sourceTree = "<group>";
@@ -1790,6 +1802,7 @@
  18C2ED7F1B9B7DE800F627B3 /* ASCollectionNode.h in Headers */,
  9C8898BD1C738BB800D6B02E /* ASTextKitFontSizeAdjuster.h in Headers */,
  B35061F51B010EFD0018CF92 /* ASCollectionView.h in Headers */,
+ ACE87A2C1D73696800D7FF06 /* ASSectionContext.h in Headers */,
  254C6B791BF94DF4003EC431 /* ASTextKitEntityAttribute.h in Headers */,
  509E68631B3AEDB4009B9150 /* ASCollectionViewLayoutController.h in Headers */,
  CC3B20841C3F76D600798563 /* ASPendingStateController.h in Headers */,
@@ -1846,6 +1859,7 @@
  DE8BEAC21C2DF3FC00D57C12 /* ASDelegateProxy.h in Headers */,
  B35062041B010EFD0018CF92 /* ASMultiplexImageNode.h in Headers */,
  B350623E1B010EFD0018CF92 /* _ASAsyncTransactionContainer+Private.h in Headers */,
+ AC6145411D8AFAE8003D62A2 /* ASSection.h in Headers */,
  DECBD6E81BE56E1900CF4905 /* ASButtonNode.h in Headers */,
  B35062241B010EFD0018CF92 /* ASMutableAttributedStringBuilder.h in Headers */,
  B13CA0F81C519EBA00E031AB /* ASCollectionViewLayoutFacilitatorProtocol.h in Headers */,
@@ -2183,6 +2197,7 @@
  257754B01BEE44CD00737CA5 /* ASTextKitRenderer+TextChecking.mm in Sources */,
  0516FA411A1563D200B4EBED /* ASMultiplexImageNode.mm in Sources */,
  DECBD6E91BE56E1900CF4905 /* ASButtonNode.mm in Sources */,
+ AC6145431D8AFD4F003D62A2 /* ASSection.m in Sources */,
  058D0A1B195D050800B7D73C /* ASMutableAttributedStringBuilder.m in Sources */,
  055B9FA91A1C154B00035D6D /* ASNetworkImageNode.mm in Sources */,
  AEB7B01B1C5962EA00662EF4 /* ASDefaultPlayButton.m in Sources */,
@@ -2367,6 +2382,7 @@
  254C6B821BF94F8A003EC431 /* ASTextKitComponents.m in Sources */,
  430E7C921B4C23F100697A4C /* ASIndexPath.m in Sources */,
  34EFC7601B701C8B00AD841F /* ASInsetLayoutSpec.mm in Sources */,
+ AC6145441D8AFD4F003D62A2 /* ASSection.m in Sources */,
  34EFC75E1B701BF000AD841F /* ASInternalHelpers.m in Sources */,
  34EFC7681B701CDE00AD841F /* ASLayout.mm in Sources */,
  DECBD6EA1BE56E1900CF4905 /* ASButtonNode.mm in Sources */,

diff --git a/AsyncDisplayKit/ASCollectionView.h b/AsyncDisplayKit/ASCollectionView.h
@@ -20,6 +20,7 @@
 @protocol ASCollectionDataSource;
 @protocol ASCollectionDelegate;
 @protocol ASCollectionViewLayoutInspecting;
+@protocol ASSectionContext;
 
 NS_ASSUME_NONNULL_BEGIN
 
@@ -230,6 +231,8 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)moveSection:(NSInteger)section toSection:(NSInteger)newSection;
 
+- (nullable id<ASSectionContext>)contextForSection:(NSInteger)section;
+
 /**
  * Inserts items at the locations identified by an array of index paths.
  *
@@ -420,6 +423,8 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)collectionViewUnlockDataSource:(ASCollectionView *)collectionView ASDISPLAYNODE_DEPRECATED;
 
+- (nullable id<ASSectionContext>)collectionView:(ASCollectionView *)collectionView contextForSection:(NSInteger)section;
+
 @end
 
 

diff --git a/AsyncDisplayKit/ASCollectionView.mm b/AsyncDisplayKit/ASCollectionView.mm
@@ -24,6 +24,7 @@
 #import "ASCollectionNode.h"
 #import "_ASDisplayLayer.h"
 #import "ASCollectionViewLayoutFacilitatorProtocol.h"
+#import "ASSectionContext.h"
 
 
 /// What, if any, invalidation should we perform during the next -layoutSubviews.
@@ -168,6 +169,7 @@ @interface ASCollectionView () <ASRangeControllerDataSource, ASRangeControllerDe
  unsigned int asyncDataSourceNodeForItemAtIndexPath:1;
  unsigned int asyncDataSourceNodeBlockForItemAtIndexPath:1;
  unsigned int asyncDataSourceNumberOfSectionsInCollectionView:1;
+ unsigned int asyncDataSourceContextForSection:1;
  } _asyncDataSourceFlags;
 
  struct {
@@ -369,6 +371,7 @@ - (void)setAsyncDataSource:(id<ASCollectionViewDataSource>)asyncDataSource
  _asyncDataSourceFlags.asyncDataSourceNodeForItemAtIndexPath = [_asyncDataSource respondsToSelector:@selector(collectionView:nodeForItemAtIndexPath:)];
  _asyncDataSourceFlags.asyncDataSourceNodeBlockForItemAtIndexPath = [_asyncDataSource respondsToSelector:@selector(collectionView:nodeBlockForItemAtIndexPath:)];
  _asyncDataSourceFlags.asyncDataSourceNumberOfSectionsInCollectionView = [_asyncDataSource respondsToSelector:@selector(numberOfSectionsInCollectionView:)];
+ _asyncDataSourceFlags.asyncDataSourceContextForSection = [_asyncDataSource respondsToSelector:@selector(collectionView:contextForSection:)];
 
  ASDisplayNodeAssert(_asyncDataSourceFlags.asyncDataSourceNodeBlockForItemAtIndexPath
  || _asyncDataSourceFlags.asyncDataSourceNodeForItemAtIndexPath, @"Data source must implement collectionView:nodeForItemAtIndexPath: or collectionView:nodeBlockForItemAtIndexPath:");
@@ -608,6 +611,12 @@ - (void)moveSection:(NSInteger)section toSection:(NSInteger)newSection
  [_dataController moveSection:section toSection:newSection withAnimationOptions:kASCollectionViewAnimationNone];
 }
 
+- (id<ASSectionContext>)contextForSection:(NSInteger)section
+{
+ ASDisplayNodeAssertMainThread();
+ return [_dataController contextForSection:section];
+}
+
 - (void)insertItemsAtIndexPaths:(NSArray *)indexPaths
 {
  ASDisplayNodeAssertMainThread();
@@ -1014,7 +1023,7 @@ - (NSUInteger)numberOfSectionsInDataController:(ASDataController *)dataControlle
  return self.strongCollectionNode;
 }
 
-#pragma mark - ASCollectionViewDataControllerSource Supplementary view support
+#pragma mark - ASCollectionViewDataControllerSource
 
 - (ASCellNode *)dataController:(ASCollectionDataController *)dataController supplementaryNodeOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
 {
@@ -1038,6 +1047,21 @@ - (NSUInteger)dataController:(ASCollectionDataController *)dataController supple
  return [self.layoutInspector collectionView:self supplementaryNodesOfKind:kind inSection:section];
 }
 
+- (id<ASSectionContext>)dataController:(ASDataController *)dataController contextForSection:(NSInteger)section
+{
+ ASDisplayNodeAssertMainThread();
+ id<ASSectionContext> context = nil;
+
+ if (_asyncDataSourceFlags.asyncDataSourceContextForSection) {
+ context = [_asyncDataSource collectionView:self contextForSection:section];
+ }
+
+ if (context != nil) {
+ context.collectionView = self;
+ }
+ return context;
+}
+
 #pragma mark - ASRangeControllerDataSource
 
 - (ASRangeController *)rangeController

diff --git a/AsyncDisplayKit/AsyncDisplayKit.h b/AsyncDisplayKit/AsyncDisplayKit.h
@@ -32,6 +32,7 @@
 #import <AsyncDisplayKit/ASCollectionViewFlowLayoutInspector.h>
 #import <AsyncDisplayKit/ASCollectionViewLayoutFacilitatorProtocol.h>
 #import <AsyncDisplayKit/ASCellNode.h>
+#import <AsyncDisplayKit/ASSectionContext.h>
 
 #import <AsyncDisplayKit/ASScrollNode.h>
 

diff --git a/AsyncDisplayKit/Details/ASCollectionDataController.h b/AsyncDisplayKit/Details/ASCollectionDataController.h
@@ -16,6 +16,9 @@
 @class ASDisplayNode;
 @class ASCollectionDataController;
 @protocol ASDataControllerSource;
+@protocol ASSectionContext;
+
+NS_ASSUME_NONNULL_BEGIN
 
 @protocol ASCollectionDataControllerSource <ASDataControllerSource>
 
@@ -28,6 +31,8 @@
 
 - (NSUInteger)dataController:(ASCollectionDataController *)dataController supplementaryNodesOfKind:(NSString *)kind inSection:(NSUInteger)section;
 
+- (nullable id<ASSectionContext>)dataController:(ASCollectionDataController *)dataController contextForSection:(NSInteger)section;
+
 @optional
 
 - (ASCellNode *)dataController:(ASCollectionDataController *)dataController supplementaryNodeOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath;
@@ -42,4 +47,8 @@
 
 - (ASCellNode *)supplementaryNodeOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath;
 
+- (nullable id<ASSectionContext>)contextForSection:(NSInteger)section;
+
 @end
+
+NS_ASSUME_NONNULL_END