Stub out ASCollectionDataController subclass

AsyncDisplayKit/ASCollectionView.mm

@@ -11,7 +11,7 @@
 #import "ASAssert.h"
 #import "ASCollectionViewLayoutController.h"
 #import "ASRangeController.h"
-#import "ASDataController.h"
+#import "ASCollectionDataController.h"
 #import "ASDisplayNodeInternal.h"
 #import "ASBatchFetching.h"
 #import "UICollectionViewLayout+ASConvenience.h"
@@ -37,9 +37,7 @@ static BOOL _isInterceptedSelector(SEL sel)
           // handled by ASCollectionView node<->cell machinery
           sel == @selector(collectionView:cellForItemAtIndexPath:) ||
           sel == @selector(collectionView:layout:sizeForItemAtIndexPath:) ||
-
-          // TODO: Supplementary views are currently not supported.  An assertion is triggered if the _asyncDataSource implements this method.
-          // sel == @selector(collectionView:viewForSupplementaryElementOfKind:atIndexPath:) ||
+          sel == @selector(collectionView:viewForSupplementaryElementOfKind:atIndexPath:) ||
           
           // handled by ASRangeController
           sel == @selector(numberOfSectionsInCollectionView:) ||
@@ -136,7 +134,7 @@ static BOOL _isInterceptedSelector(SEL sel)
   _ASCollectionViewProxy *_proxyDataSource;
   _ASCollectionViewProxy *_proxyDelegate;
 
-  ASDataController *_dataController;
+  ASCollectionDataController *_dataController;
   ASRangeController *_rangeController;
   ASCollectionViewLayoutController *_layoutController;
 
@@ -201,7 +199,7 @@ static BOOL _isInterceptedSelector(SEL sel)
   _rangeController.delegate = self;
   _rangeController.layoutController = _layoutController;
 
-  _dataController = [[ASDataController alloc] initWithAsyncDataFetching:asyncDataFetchingEnabled];
+  _dataController = [[ASCollectionDataController alloc] initWithAsyncDataFetching:asyncDataFetchingEnabled];
   _dataController.delegate = _rangeController;
   _dataController.dataSource = self;
 
@@ -381,8 +379,8 @@ static BOOL _isInterceptedSelector(SEL sel)
 
 - (void)registerSupplementaryViewOfKind:(NSString *)elementKind
 {
-  NSString *identifier = [NSString stringWithFormat:@"_ASCollectionSupplementaryView_%@", elementKind];
-  [self registerClass:[UIView class] forSupplementaryViewOfKind:elementKind withReuseIdentifier:identifier];
+  [self registerClass:[UICollectionReusableView class] forSupplementaryViewOfKind:elementKind
+                                            withReuseIdentifier:[self __reuseIdentifierForKind:elementKind]];
 }
 
 - (void)insertSections:(NSIndexSet *)sections
@@ -433,6 +431,16 @@ static BOOL _isInterceptedSelector(SEL sel)
   [_dataController moveRowAtIndexPath:indexPath toIndexPath:newIndexPath withAnimationOptions:kASCollectionViewAnimationNone];
 }
 
+- (ASCellNode *)nodeForItemAtIndexPath:(NSIndexPath *)indexPath
+{
+  return [_dataController nodeAtIndexPath:indexPath];
+}
+
+- (NSString *)__reuseIdentifierForKind:(NSString *)kind
+{
+  return [NSString stringWithFormat:@"_ASCollectionSupplementaryView_%@", kind];
+}
+
 #pragma mark -
 #pragma mark Intercepted selectors.
 
@@ -443,7 +451,8 @@ static BOOL _isInterceptedSelector(SEL sel)
   _ASCollectionViewCell *cell = [self dequeueReusableCellWithReuseIdentifier:reuseIdentifier forIndexPath:indexPath];
 
   ASCellNode *node = [_dataController nodeAtIndexPath:indexPath];
-  [_rangeController configureContentView:cell.contentView forCellNode:node];
+  
+  [_rangeController configureContentView:cell.contentView forNode:node];
   
   cell.node = node;
   
@@ -455,6 +464,15 @@ static BOOL _isInterceptedSelector(SEL sel)
   return [[_dataController nodeAtIndexPath:indexPath] calculatedSize];
 }
 
+- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
+{
+  NSString *identifier = [self __reuseIdentifierForKind:kind];
+  UICollectionReusableView *view = [self dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:identifier forIndexPath:indexPath];
+  ASDisplayNode *node = [_dataController supplementaryNodeOfKind:kind atIndexPath:indexPath];
+  [_rangeController configureContentView:view forNode:node];
+  return view;
+}
+
 - (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
 {
   _superIsPendingDataLoad = NO;
@@ -613,6 +631,11 @@ static BOOL _isInterceptedSelector(SEL sel)
   return node;
 }
 
+- (ASDisplayNode *)dataController:(ASDataController *)dataController supplementaryNodeOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
+{
+  return [_asyncDataSource collectionView:self nodeForSupplementaryElementOfKind:kind atIndexPath:indexPath];
+}
+
 - (ASSizeRange)dataController:(ASDataController *)dataController constrainedSizeForNodeAtIndexPath:(NSIndexPath *)indexPath
 {
   ASSizeRange constrainedSize;
@@ -659,7 +682,7 @@ static BOOL _isInterceptedSelector(SEL sel)
   return [_asyncDataSource collectionView:self numberOfItemsInSection:section];
 }
 
-- (NSUInteger)dataControllerNumberOfSections:(ASDataController *)dataController {
+- (NSUInteger)numberOfSectionsInDataController:(ASDataController *)dataController {
   if ([_asyncDataSource respondsToSelector:@selector(numberOfSectionsInCollectionView:)]) {
     return [_asyncDataSource numberOfSectionsInCollectionView:self];
   } else {

AsyncDisplayKit/ASTableView.mm

@@ -530,7 +530,7 @@ void ASPerformBlockWithoutAnimation(BOOL withoutAnimation, void (^block)()) {
   }
 
   ASCellNode *node = [_dataController nodeAtIndexPath:indexPath];
-  [_rangeController configureContentView:cell.contentView forCellNode:node];
+  [_rangeController configureContentView:cell.contentView forNode:node];
 
   cell.node = node;
   cell.backgroundColor = node.backgroundColor;
@@ -859,7 +859,7 @@ void ASPerformBlockWithoutAnimation(BOOL withoutAnimation, void (^block)()) {
   return [_asyncDataSource tableView:self numberOfRowsInSection:section];
 }
 
-- (NSUInteger)dataControllerNumberOfSections:(ASDataController *)dataController
+- (NSUInteger)numberOfSectionsInDataController:(ASDataController *)dataController
 {
   if ([_asyncDataSource respondsToSelector:@selector(numberOfSectionsInTableView:)]) {
     return [_asyncDataSource numberOfSectionsInTableView:self];

AsyncDisplayKit/Details/ASCollectionDataController.h

@@ -0,0 +1,26 @@
+//
+//  ASCollectionDataController.h
+//  Pods
+//
+//  Created by Levi McCallum on 9/22/15.
+//
+//
+
+#import <AsyncDisplayKit/ASDataController.h>
+
+@class ASDisplayNode, ASCollectionDataController;
+@protocol ASDataControllerSource;
+
+@protocol ASCollectionDataControllerSource <ASDataControllerSource>
+
+- (ASDisplayNode *)dataController:(ASDataController *)dataController supplementaryNodeOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath;
+
+- (NSArray *)supplementaryKindsInDataController:(ASCollectionDataController *)dataController;
+
+@end
+
+@interface ASCollectionDataController : ASDataController
+
+- (ASDisplayNode *)supplementaryNodeOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath;
+
+@end

AsyncDisplayKit/Details/ASCollectionDataController.m

@@ -0,0 +1,72 @@
+//
+//  ASCollectionDataController.m
+//  Pods
+//
+//  Created by Levi McCallum on 9/22/15.
+//
+//
+
+#import "ASCollectionDataController.h"
+
+#import "ASAssert.h"
+
+@interface ASDataController (Subclasses)
+
+/**
+ * Queues the given operation until an `endUpdates` synchronize update is completed.
+ *
+ * If this method is called outside of a begin/endUpdates batch update, the block is
+ * executed immediately.
+ */
+- (void)performEditCommandWithBlock:(void (^)(void))block;
+
+/**
+ * Safely locks access to the data source and executes the given block, unlocking once complete.
+ *
+ * When `asyncDataFetching` is enabled, the block is executed on a background thread.
+ */
+- (void)accessDataSourceWithBlock:(dispatch_block_t)block;
+
+@end
+
+@implementation ASCollectionDataController {
+  NSMutableDictionary *_completedSupplementaryNodes;
+  NSMutableDictionary *_editingSupplementaryNodes;
+}
+
+- (void)initialSupplementaryLoading
+{
+  [self performEditCommandWithBlock:^{
+    ASDisplayNodeAssertMainThread();
+    [self accessDataSourceWithBlock:^{
+      NSArray *elementKinds = [self.collectionDataSource supplementaryKindsInDataController:self];
+    }];
+  }];
+}
+
+- (ASDisplayNode *)supplementaryNodeOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
+{
+  ASDisplayNodeAssertMainThread();
+  return _completedSupplementaryNodes[kind][indexPath.section][indexPath.item];
+}
+
+- (id<ASCollectionDataControllerSource>)collectionDataSource
+{
+  return (id<ASCollectionDataControllerSource>)self.dataSource;
+}
+
+#pragma mark - Internal Data Querying
+
+- (void)_insertNodes:(NSArray *)nodes ofKind:(NSString *)kind atIndexPaths:(NSArray *)indexPaths
+{
+  if (indexPaths.count == 0)
+    return;
+}
+
+- (void)_deleteNodesOfKind:(NSString *)kind atIndexPaths:(NSArray *)indexPaths
+{
+  if (indexPaths.count == 0)
+    return;
+}
+
+@end

AsyncDisplayKit/Details/ASDataController.h

@@ -40,7 +40,7 @@ typedef NSUInteger ASDataControllerAnimationOptions;
 /**
  Fetch the number of sections.
  */
-- (NSUInteger)dataControllerNumberOfSections:(ASDataController *)dataController;
+- (NSUInteger)numberOfSectionsInDataController:(ASDataController *)dataController;
 
 /**
  Lock the data source for data fetching.

AsyncDisplayKit/Details/ASDataController.mm

@@ -239,7 +239,7 @@ static void *kASSizingQueueContext = &kASSizingQueueContext;
     ASDisplayNodeAssertMainThread();
     [self accessDataSourceWithBlock:^{
       NSMutableArray *indexPaths = [NSMutableArray array];
-      NSUInteger sectionNum = [_dataSource dataControllerNumberOfSections:self];
+      NSUInteger sectionNum = [_dataSource numberOfSectionsInDataController:self];
 
       // insert sections
       [self insertSections:[NSIndexSet indexSetWithIndexesInRange:NSMakeRange(0, sectionNum)] withAnimationOptions:0];
@@ -266,7 +266,7 @@ static void *kASSizingQueueContext = &kASSizingQueueContext;
     [_editingTransactionQueue waitUntilAllOperationsAreFinished];
 
     [self accessDataSourceWithBlock:^{
-      NSUInteger sectionCount = [_dataSource dataControllerNumberOfSections:self];
+      NSUInteger sectionCount = [_dataSource numberOfSectionsInDataController:self];
       NSMutableArray *updatedNodes = [NSMutableArray array];
       NSMutableArray *updatedIndexPaths = [NSMutableArray array];
       [self _populateFromEntireDataSourceWithMutableNodes:updatedNodes mutableIndexPaths:updatedIndexPaths];
@@ -335,7 +335,7 @@ static void *kASSizingQueueContext = &kASSizingQueueContext;
 
 - (void)_populateFromEntireDataSourceWithMutableNodes:(NSMutableArray *)nodes mutableIndexPaths:(NSMutableArray *)indexPaths
 {
-  NSUInteger sectionNum = [_dataSource dataControllerNumberOfSections:self];
+  NSUInteger sectionNum = [_dataSource numberOfSectionsInDataController:self];
   for (NSUInteger i = 0; i < sectionNum; i++) {
     NSIndexPath *sectionIndexPath = [[NSIndexPath alloc] initWithIndex:i];
     

AsyncDisplayKit/Details/ASRangeController.h

@@ -41,9 +41,9 @@
  *
  * @param contentView UIView to add a (sized) node's view to.
  *
- * @param node The ASCellNode to be added.
+ * @param node The node to be added. Often an ASCellNode.
  */
-- (void)configureContentView:(UIView *)contentView forCellNode:(ASCellNode *)node;
+- (void)configureContentView:(UIView *)contentView forNode:(ASDisplayNode *)node;
 
 /**
  * Delegate and ultimate data source.  Must not be nil.

AsyncDisplayKit/Details/ASRangeController.mm

@@ -48,7 +48,7 @@
 
 #pragma mark - View manipulation
 
-- (void)moveNode:(ASCellNode *)node toView:(UIView *)view
+- (void)moveNode:(ASDisplayNode *)node toView:(UIView *)view
 {
   ASDisplayNodeAssertMainThread();
   ASDisplayNodeAssert(node, @"Cannot move a nil node to a view");
@@ -158,7 +158,7 @@
   return rangeType == ASLayoutRangeTypeRender;
 }
 
-- (void)configureContentView:(UIView *)contentView forCellNode:(ASCellNode *)cellNode
+- (void)configureContentView:(UIView *)contentView forNode:(ASDisplayNode *)cellNode
 {
   if (cellNode.view.superview == contentView) {
     // this content view is already correctly configured

AsyncDisplayKit/Details/ASRangeHandlerRender.mm

@@ -64,7 +64,7 @@
   //    This happens if the UITableViewCell is reused after scrolling offscreen.  Because the node has already been given the opportunity to display, we do not
   //    proactively re-host it within the workingWindow (improving efficiency).  Some time later, it may fall outside the working range, in which case calling
   //    -recursivelyClearContents is critical.  If the user scrolls back and it is re-hosted in a UITableViewCell, the content will still exist as it is not cleared
-  //    by simply being removed from the cell.  The code that usually triggers this condition is the -removeFromSuperview in -[ASRangeController configureContentView:forCellNode:].
+  //    by simply being removed from the cell.  The code that usually triggers this condition is the -removeFromSuperview in -[ASRangeController configureContentView:forNode:].
   // Condition #4 is suboptimal in some cases, as it is conceivable that memory warnings could trigger clearing content that is inside the working range.  However, enforcing the
   // preservation of this content could result in the app being killed, which is not likely preferable over briefly seeing placeholders in the event the user scrolls backwards.
   // Nonetheless, future changes to the implementation will likely eliminate this behavior to simplify debugging and extensibility of working range functionality.