ASCollectionView batch API

AsyncDisplayKit/ASCollectionView.h

@@ -11,6 +11,7 @@
 #import <AsyncDisplayKit/ASRangeController.h>
 #import <AsyncDisplayKit/ASCollectionViewProtocols.h>
 #import <AsyncDisplayKit/ASBaseDefines.h>
+#import <AsyncDisplayKit/ASBatchContext.h>
 
 
 @class ASCellNode;
@@ -62,6 +63,13 @@
  */
 - (instancetype)initWithFrame:(CGRect)frame collectionViewLayout:(UICollectionViewLayout *)layout asyncDataFetching:(BOOL)asyncDataFetchingEnabled;
 
+/**
+ * The number of screens left to scroll before the delegate -collectionView:beginBatchFetchingWithContext: is called.
+ *
+ * Defaults to one screenful.
+ */
+@property (nonatomic, assign) CGFloat leadingScreensForBatching;
+
 /**
  * Reload everything from scratch, destroying the working range and all cached nodes.
  *
@@ -166,6 +174,34 @@
 - (void)collectionView:(ASCollectionView *)collectionView willDisplayNodeForItemAtIndexPath:(NSIndexPath *)indexPath;
 - (void)collectionView:(ASCollectionView *)collectionView didEndDisplayingNodeForItemAtIndexPath:(NSIndexPath*)indexPath;
 
+/**
+ * Tell the collectionView if batch fetching should begin.
+ *
+ * @param collectionView The sender.
+ *
+ * @discussion Use this method to conditionally fetch batches. Example use cases are: limiting the total number of
+ * objects that can be fetched or no network connection.
+ *
+ * If not implemented, the collectionView assumes that it should notify its asyncDelegate when batch fetching
+ * should occur.
+ */
+- (BOOL)shouldBatchFetchForCollectionView:(UICollectionView *)collectionView;
+
+/**
+ * Receive a message that the collectionView is near the end of its data set and more data should be fetched if 
+ * necessary.
+ *
+ * @param tableView The sender.
+ * @param context A context object that must be notified when the batch fetch is completed.
+ *
+ * @discussion You must eventually call -completeBatchFetching: with an argument of YES in order to receive future
+ * notifications to do batch fetches.
+ *
+ * UICollectionView currently only supports batch events for tail loads. If you require a head load, consider
+ * implementing a UIRefreshControl.
+ */
+- (void)collectionView:(UICollectionView *)collectionView beginBatchFetchingWithContext:(ASBatchContext *)context;
+
 @end
 
 @interface ASCollectionView (Deprecated)