Adding visibility monitoring for ASTableVieww

AsyncDisplayKit/ASCellNode.h

@@ -76,8 +76,6 @@ typedef NSUInteger ASCellNodeAnimation;
  */
 @property (nonatomic, weak) id<ASCellNodeLayoutDelegate> layoutDelegate;
 
-@property (nonatomic, assign, readonly) BOOL shouldMonitorScrollViewDidScroll;
-
 /*
  * ASCellNode must forward touch events in order for UITableView and UICollectionView tap handling to work. Overriding
  * these methods (e.g. for highlighting) requires the super method be called.
@@ -110,7 +108,8 @@ typedef NSUInteger ASCellNodeAnimation;
  */
 - (instancetype)initWithViewControllerBlock:(ASDisplayNodeViewControllerBlock)viewControllerBlock didLoadBlock:(ASDisplayNodeDidLoadBlock)didLoadBlock;
 
-- (void)_visibleNodeDidScroll:(UIScrollView *)scrollView withCellFrame:(CGRect)cellFrame;
+- (void)visibleNodeDidScroll:(UIScrollView *)scrollView withCellFrame:(CGRect)cellFrame;
+
 @end
 
 

AsyncDisplayKit/ASCellNode.m

@@ -133,7 +133,7 @@
   [(_ASDisplayView *)self.view __forwardTouchesCancelled:touches withEvent:event];
 }
 
-- (void)_visibleNodeDidScroll:(UIScrollView *)scrollView withCellFrame:(CGRect)cellFrame
+- (void)visibleNodeDidScroll:(UIScrollView *)scrollView withCellFrame:(CGRect)cellFrame
 {
     // To be overriden by subclasses
 }

AsyncDisplayKit/ASCollectionView.mm

@@ -530,7 +530,7 @@ static NSString * const kCellReuseIdentifier = @"_ASCollectionViewCell";
   return cell;
 }
 
-- (void)collectionView:(UICollectionView *)collectionView willDisplayCell:(UICollectionViewCell *)cell forItemAtIndexPath:(NSIndexPath *)indexPath
+- (void)collectionView:(UICollectionView *)collectionView willDisplayCell:(_ASCollectionViewCell *)cell forItemAtIndexPath:(NSIndexPath *)indexPath
 {
   [_rangeController visibleNodeIndexPathsDidChangeWithScrollDirection:[self scrollDirection]];
   
@@ -538,7 +538,7 @@ static NSString * const kCellReuseIdentifier = @"_ASCollectionViewCell";
     [_asyncDelegate collectionView:self willDisplayNodeForItemAtIndexPath:indexPath];
   }
   
-  ASCellNode *cellNode = [self nodeForItemAtIndexPath:indexPath];
+  ASCellNode *cellNode = [cell node];
   if (cellNode.neverShowPlaceholders) {
     [cellNode recursivelyEnsureDisplaySynchronously:YES];
   }
@@ -681,7 +681,7 @@ static NSString * const kCellReuseIdentifier = @"_ASCollectionViewCell";
   for (_ASCollectionViewCell *collectionCell in _cellsForVisibilityUpdates) {
     ASCellNode *node = [collectionCell node];
     // Only nodes that respond to the selector are added to _cellsForVisibilityUpdates
-    [node _visibleNodeDidScroll:scrollView withCellFrame:collectionCell.frame];
+    [node visibleNodeDidScroll:scrollView withCellFrame:collectionCell.frame];
   }
   if (_asyncDelegateImplementsScrollviewDidScroll) {
     [_asyncDelegate scrollViewDidScroll:scrollView];

AsyncDisplayKit/ASTableView.mm

@@ -112,6 +112,8 @@ static NSString * const kCellReuseIdentifier = @"_ASTableViewCell";
   BOOL _queuedNodeHeightUpdate;
   BOOL _isDeallocating;
   BOOL _dataSourceImplementsNodeBlockForRowAtIndexPath;
+  BOOL _asyncDelegateImplementsScrollviewDidScroll;
+  NSMutableSet *_cellsForVisibilityUpdates;
 }
 
 @property (atomic, assign) BOOL asyncDataSourceLocked;
@@ -197,7 +199,7 @@ static NSString * const kCellReuseIdentifier = @"_ASTableViewCell";
   if (!(self = [super initWithFrame:frame style:style])) {
     return nil;
   }
-  
+  _cellsForVisibilityUpdates = [NSMutableSet set];
   if (!dataControllerClass) {
     dataControllerClass = [[self class] dataControllerClass];
   }
@@ -585,7 +587,18 @@ static NSString * const kCellReuseIdentifier = @"_ASTableViewCell";
   return direction;
 }
 
-- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
+- (void)scrollViewDidScroll:(UIScrollView *)scrollView
+{
+  for (_ASTableViewCell *tableCell in _cellsForVisibilityUpdates) {
+    ASCellNode *node = [tableCell node];
+    [node visibleNodeDidScroll:scrollView withCellFrame:tableCell.frame];
+  }
+  if (_asyncDelegateImplementsScrollviewDidScroll) {
+    [_asyncDelegate scrollViewDidScroll:scrollView];
+  }
+}
+
+- (void)tableView:(UITableView *)tableView willDisplayCell:(_ASTableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
 {
   _pendingVisibleIndexPath = indexPath;
 
@@ -595,13 +608,17 @@ static NSString * const kCellReuseIdentifier = @"_ASTableViewCell";
     [_asyncDelegate tableView:self willDisplayNodeForRowAtIndexPath:indexPath];
   }
 
-  ASCellNode *cellNode = [self nodeForRowAtIndexPath:indexPath];
+  ASCellNode *cellNode = [cell node];
+
+  if (ASSubclassOverridesSelector([ASCellNode class], [cellNode class], @selector(visibleNodeDidScroll:withCellFrame:))) {
+    [_cellsForVisibilityUpdates addObject:cell];
+  }
   if (cellNode.neverShowPlaceholders) {
     [cellNode recursivelyEnsureDisplaySynchronously:YES];
   }
 }
 
-- (void)tableView:(UITableView *)tableView didEndDisplayingCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath*)indexPath
+- (void)tableView:(UITableView *)tableView didEndDisplayingCell:(_ASTableViewCell *)cell forRowAtIndexPath:(NSIndexPath*)indexPath
 {
   if ([_pendingVisibleIndexPath isEqual:indexPath]) {
     _pendingVisibleIndexPath = nil;
@@ -615,6 +632,10 @@ static NSString * const kCellReuseIdentifier = @"_ASTableViewCell";
     [_asyncDelegate tableView:self didEndDisplayingNode:node forRowAtIndexPath:indexPath];
   }
 
+  if ([_cellsForVisibilityUpdates containsObject:cell]) {
+    [_cellsForVisibilityUpdates removeObject:cell];
+  }
+
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wdeprecated-declarations"
   if ([_asyncDelegate respondsToSelector:@selector(tableView:didEndDisplayingNodeForRowAtIndexPath:)]) {

AsyncDisplayKit/Details/ASDelegateProxy.m

@@ -24,6 +24,9 @@
           selector == @selector(numberOfSectionsInTableView:) ||
           selector == @selector(tableView:numberOfRowsInSection:) ||
           
+          // used for ASCellNode visibility
+          selector == @selector(scrollViewDidScroll:) ||
+          
           // used for ASRangeController visibility updates
           selector == @selector(tableView:willDisplayCell:forRowAtIndexPath:) ||
           selector == @selector(tableView:didEndDisplayingCell:forRowAtIndexPath:) ||