Range controller registers to rendering engine and extern to full range if needed

AsyncDisplayKit/ASDisplayNode.mm

@@ -29,6 +29,7 @@
 #import "ASCellNode.h"
 
 NSInteger const ASDefaultDrawingPriority = ASDefaultTransactionPriority;
+NSString * const ASRenderingEngineDidDisplayScheduledNodesNotification = @"ASRenderingEngineDidDisplayScheduledNodes";
 
 @interface _ASDisplayNodePosition : NSObject
 
@@ -279,6 +280,8 @@ static ASDisplayNodeMethodOverrides GetASDisplayNodeMethodOverrides(Class c)
       for (ASDisplayNode *node in displayingNodes) {
         [node __recursivelyTriggerDisplayAndBlock:NO];
       }
+      [[NSNotificationCenter defaultCenter] postNotificationName:ASRenderingEngineDidDisplayScheduledNodesNotification
+                                                          object:nil];
     });
   }
 }

AsyncDisplayKit/Details/ASAbstractLayoutController.mm

@@ -11,8 +11,7 @@
 #include <vector>
 
 @interface ASAbstractLayoutController () {
-  std::vector<ASRangeTuningParameters> _tuningParameters;
-  std::vector<ASRangeTuningParameters> _minimumTuningParameters;
+  std::vector<std::vector<ASRangeTuningParameters>> _tuningParameters;
   CGSize _viewportSize;
 }
 @end
@@ -25,34 +24,34 @@
     return nil;
   }
   
-  _tuningParameters = std::vector<ASRangeTuningParameters>(ASLayoutRangeTypeCount);
-  _tuningParameters[ASLayoutRangeTypeVisible] = {
-    .leadingBufferScreenfuls = 0,
-    .trailingBufferScreenfuls = 0
-  };
-  _tuningParameters[ASLayoutRangeTypeDisplay] = {
-    .leadingBufferScreenfuls = 1.5,
-    .trailingBufferScreenfuls = 0.75
-  };
-  _tuningParameters[ASLayoutRangeTypeFetchData] = {
-    .leadingBufferScreenfuls = 3,
-    .trailingBufferScreenfuls = 2
-  };
+  _tuningParameters = std::vector<std::vector<ASRangeTuningParameters>> (ASLayoutRangeModeCount, std::vector<ASRangeTuningParameters> (ASLayoutRangeTypeCount));
   
-  _minimumTuningParameters = std::vector<ASRangeTuningParameters>(ASLayoutRangeTypeCount);
-  _minimumTuningParameters[ASLayoutRangeTypeVisible] = {
+  _tuningParameters[ASLayoutRangeModeMinimum][ASLayoutRangeTypeVisible] = {
     .leadingBufferScreenfuls = 0,
     .trailingBufferScreenfuls = 0
   };
-  _minimumTuningParameters[ASLayoutRangeTypeDisplay] = {
+  _tuningParameters[ASLayoutRangeModeMinimum][ASLayoutRangeTypeDisplay] = {
     .leadingBufferScreenfuls = 0.25,
     .trailingBufferScreenfuls = 0.25
   };
-  _minimumTuningParameters[ASLayoutRangeTypeFetchData] = {
+  _tuningParameters[ASLayoutRangeModeMinimum][ASLayoutRangeTypeFetchData] = {
     .leadingBufferScreenfuls = 1,
     .trailingBufferScreenfuls = 1
   };
 
+  _tuningParameters[ASLayoutRangeModeFull][ASLayoutRangeTypeVisible] = {
+    .leadingBufferScreenfuls = 0,
+    .trailingBufferScreenfuls = 0
+  };
+  _tuningParameters[ASLayoutRangeModeFull][ASLayoutRangeTypeDisplay] = {
+    .leadingBufferScreenfuls = 1.5,
+    .trailingBufferScreenfuls = 0.75
+  };
+  _tuningParameters[ASLayoutRangeModeFull][ASLayoutRangeTypeFetchData] = {
+    .leadingBufferScreenfuls = 3,
+    .trailingBufferScreenfuls = 2
+  };
+  
   return self;
 }
 
@@ -60,33 +59,28 @@
 
 - (ASRangeTuningParameters)tuningParametersForRangeType:(ASLayoutRangeType)rangeType
 {
-  ASDisplayNodeAssert(rangeType < _tuningParameters.size(), @"Requesting a range that is OOB for the configured tuning parameters");
-  return _tuningParameters[rangeType];
+  return [self tuningParametersForRangeMode:ASLayoutRangeModeFull rangeType:rangeType];
 }
 
 - (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeType:(ASLayoutRangeType)rangeType
 {
-  ASDisplayNodeAssert(rangeType < _tuningParameters.size(), @"Requesting a range that is OOB for the configured tuning parameters");
-  ASDisplayNodeAssert(rangeType != ASLayoutRangeTypeVisible, @"Must not set Visible range tuning parameters (always 0, 0)");
-  _tuningParameters[rangeType] = tuningParameters;
+  return [self setTuningParameters:tuningParameters forRangeMode:ASLayoutRangeModeFull rangeType:rangeType];
 }
 
-- (ASRangeTuningParameters)minimumTuningParametersForRangeType:(ASLayoutRangeType)rangeType
+- (ASRangeTuningParameters)tuningParametersForRangeMode:(ASLayoutRangeMode)rangeMode rangeType:(ASLayoutRangeType)rangeType
 {
-  ASDisplayNodeAssert(rangeType < _minimumTuningParameters.size(), @"Requesting a range that is OOB for the configured minimum tuning parameters");
-  return _minimumTuningParameters[rangeType];
+  ASDisplayNodeAssert(rangeMode < _tuningParameters.size() && rangeType < _tuningParameters[rangeMode].size(),
+                      @"Requesting a range that is OOB for the configured tuning parameters");
+  return _tuningParameters[rangeMode][rangeType];
 }
 
-- (void)setMinimumTuningParameters:(ASRangeTuningParameters)minimumTuningParameters forRangeType:(ASLayoutRangeType)rangeType
+- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeMode:(ASLayoutRangeMode)rangeMode rangeType:(ASLayoutRangeType)rangeType
 {
-  ASDisplayNodeAssert(rangeType < _minimumTuningParameters.size(), @"Requesting a range that is OOB for the configured minimum tuning parameters");
-  ASDisplayNodeAssert(rangeType != ASLayoutRangeTypeVisible, @"Must not set Visible range minimum tuning parameters (always 0, 0)");
-  _minimumTuningParameters[rangeType] = minimumTuningParameters;
-}
-
-- (ASRangeTuningParameters)tuningParametersForRangeType:(ASLayoutRangeType)rangeType isFullRange:(BOOL)isFullRange
-{
-  return isFullRange ? [self tuningParametersForRangeType:rangeType] : [self minimumTuningParametersForRangeType:rangeType];
+  ASDisplayNodeAssert(rangeMode < _tuningParameters.size() && rangeType < _tuningParameters[rangeMode].size(),
+                      @"Setting a range that is OOB for the configured tuning parameters");
+  ASDisplayNodeAssert(rangeType != ASLayoutRangeTypeVisible,
+                      @"Must not set Visible range minimum tuning parameters (always 0, 0)");
+  _tuningParameters[rangeMode][rangeType] = tuningParameters;
 }
 
 #pragma mark - Abstract Index Path Range Support
@@ -98,7 +92,7 @@
   return NO;
 }
 
-- (NSSet *)indexPathsForScrolling:(ASScrollDirection)scrollDirection rangeType:(ASLayoutRangeType)rangeType shouldUseFullRange:(BOOL)shouldUseFullRange
+- (NSSet *)indexPathsForScrolling:(ASScrollDirection)scrollDirection rangeMode:(ASLayoutRangeMode)rangeMode rangeType:(ASLayoutRangeType)rangeType
 {
   ASDisplayNodeAssertNotSupported();
   return nil;

AsyncDisplayKit/Details/ASCollectionViewLayoutController.mm

@@ -66,9 +66,9 @@ typedef struct ASRangeGeometry ASRangeGeometry;
   return self;
 }
 
-- (NSSet *)indexPathsForScrolling:(ASScrollDirection)scrollDirection rangeType:(ASLayoutRangeType)rangeType shouldUseFullRange:(BOOL)shouldUseFullRange
+- (NSSet *)indexPathsForScrolling:(ASScrollDirection)scrollDirection rangeMode:(ASLayoutRangeMode)rangeMode rangeType:(ASLayoutRangeType)rangeType
 {
-  ASRangeTuningParameters tuningParameters = [self tuningParametersForRangeType:rangeType isFullRange:shouldUseFullRange];
+  ASRangeTuningParameters tuningParameters = [self tuningParametersForRangeMode:rangeMode rangeType:rangeType];
   ASRangeGeometry rangeGeometry = [self rangeGeometryWithScrollDirection:scrollDirection tuningParameters:tuningParameters];
   _updateRangeBoundsIndexedByRangeType[rangeType] = rangeGeometry.updateBounds;
   return [self indexPathsForItemsWithinRangeBounds:rangeGeometry.rangeBounds];
@@ -133,9 +133,9 @@ typedef struct ASRangeGeometry ASRangeGeometry;
 
 @implementation ASCollectionViewLayoutControllerBeta
 
-- (NSSet *)indexPathsForScrolling:(ASScrollDirection)scrollDirection rangeType:(ASLayoutRangeType)rangeType shouldUseFullRange:(BOOL)shouldUseFullRange
+- (NSSet *)indexPathsForScrolling:(ASScrollDirection)scrollDirection rangeMode:(ASLayoutRangeMode)rangeMode rangeType:(ASLayoutRangeType)rangeType
 {
-  ASRangeTuningParameters tuningParameters = [self tuningParametersForRangeType:rangeType isFullRange:shouldUseFullRange];
+  ASRangeTuningParameters tuningParameters = [self tuningParametersForRangeMode:rangeMode rangeType:rangeType];
   CGRect rangeBounds = [self rangeBoundsWithScrollDirection:scrollDirection rangeTuningParameters:tuningParameters];
   return [self indexPathsForItemsWithinRangeBounds:rangeBounds];
 }

AsyncDisplayKit/Details/ASFlowLayoutController.mm

@@ -74,7 +74,7 @@ static const CGFloat kASFlowLayoutControllerRefreshingThreshold = 0.3;
  * IndexPath array for the element in the working range.
  */
 
-- (NSSet *)indexPathsForScrolling:(ASScrollDirection)scrollDirection rangeType:(ASLayoutRangeType)rangeType shouldUseFullRange:(BOOL)shouldUseFullRange
+- (NSSet *)indexPathsForScrolling:(ASScrollDirection)scrollDirection rangeMode:(ASLayoutRangeMode)rangeMode rangeType:(ASLayoutRangeType)rangeType
 {
   CGFloat viewportScreenMetric;
   ASScrollDirection leadingDirection;
@@ -92,7 +92,7 @@ static const CGFloat kASFlowLayoutControllerRefreshingThreshold = 0.3;
     leadingDirection = ASScrollDirectionUp;
   }
 
-  ASRangeTuningParameters tuningParameters = [self tuningParametersForRangeType:rangeType isFullRange:shouldUseFullRange];
+  ASRangeTuningParameters tuningParameters = [self tuningParametersForRangeMode:rangeMode rangeType:rangeType];
   CGFloat backScreens = scrollDirection == leadingDirection ? tuningParameters.leadingBufferScreenfuls : tuningParameters.trailingBufferScreenfuls;
   CGFloat frontScreens = scrollDirection == leadingDirection ? tuningParameters.trailingBufferScreenfuls : tuningParameters.leadingBufferScreenfuls;
 

AsyncDisplayKit/Details/ASLayoutController.h

@@ -16,6 +16,12 @@ NS_ASSUME_NONNULL_BEGIN
 
 @class ASCellNode;
 
+typedef NS_ENUM(NSUInteger, ASLayoutRangeMode) {
+  ASLayoutRangeModeMinimum = 0,
+  ASLayoutRangeModeFull,
+  ASLayoutRangeModeCount
+};
+
 typedef struct {
   CGFloat leadingBufferScreenfuls;
   CGFloat trailingBufferScreenfuls;
@@ -24,23 +30,30 @@ typedef struct {
 @protocol ASLayoutController <NSObject>
 
 /**
- * Tuning parameters for the range.
+ * Tuning parameters for the range type in full mode. This method is deprecated. 
+ * Instead, use -setTuningParameters:forRangeMode:rangeType:
+ *
+ * @see setTuningParameters:forRangeMode:rangeType:
  */
-- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeType:(ASLayoutRangeType)rangeType;
+- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeType:(ASLayoutRangeType)rangeType ASDISPLAYNODE_DEPRECATED;
 
-- (ASRangeTuningParameters)tuningParametersForRangeType:(ASLayoutRangeType)rangeType;
+/**
+ * Get tuning parameters for the range type in full mode. This method is deprecated.
+ * Instead, use -tuningParametersForRangeMode:rangeType:
+ *
+ * @see tuningParametersForRangeMode:rangeType:
+ */
+- (ASRangeTuningParameters)tuningParametersForRangeType:(ASLayoutRangeType)rangeType ASDISPLAYNODE_DEPRECATED;
 
-- (void)setMinimumTuningParameters:(ASRangeTuningParameters)minimumTuningParameters forRangeType:(ASLayoutRangeType)rangeType;
+- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeMode:(ASLayoutRangeMode)rangeMode rangeType:(ASLayoutRangeType)rangeType;
 
-- (ASRangeTuningParameters)minimumTuningParametersForRangeType:(ASLayoutRangeType)rangeType;
-
-- (ASRangeTuningParameters)tuningParametersForRangeType:(ASLayoutRangeType)rangeType isFullRange:(BOOL)isFullRange;
+- (ASRangeTuningParameters)tuningParametersForRangeMode:(ASLayoutRangeMode)rangeMode rangeType:(ASLayoutRangeType)rangeType;
 
 // FIXME: This method can be removed once ASRangeControllerBeta becomes the main version.
 // TODO: Now that it is the main version, can we remove this now?
 - (BOOL)shouldUpdateForVisibleIndexPaths:(NSArray<NSIndexPath *> *)indexPaths rangeType:(ASLayoutRangeType)rangeType;
 
-- (NSSet *)indexPathsForScrolling:(ASScrollDirection)scrollDirection rangeType:(ASLayoutRangeType)rangeType shouldUseFullRange:(BOOL)shouldUseFullRange;
+- (NSSet *)indexPathsForScrolling:(ASScrollDirection)scrollDirection rangeMode:(ASLayoutRangeMode)rangeMode rangeType:(ASLayoutRangeType)rangeType;
 
 @optional
 

AsyncDisplayKit/Details/ASRangeController.mm

@@ -153,7 +153,9 @@
     id<ASRangeHandler> rangeHandler = _rangeTypeHandlers[rangeKey];
 
     if (!_rangeIsValid || [_layoutController shouldUpdateForVisibleIndexPaths:visibleNodePaths rangeType:rangeType]) {
-      NSSet *indexPaths = [_layoutController indexPathsForScrolling:_scrollDirection rangeType:rangeType shouldUseFullRange:YES];
+      NSSet *indexPaths = [_layoutController indexPathsForScrolling:_scrollDirection
+                                                          rangeMode:ASLayoutRangeModeFull
+                                                          rangeType:rangeType];
 
       // Notify to remove indexpaths that are leftover that are not visible or included in the _layoutController calculated paths
       NSMutableSet *removedIndexPaths = _rangeIsValid ? [_rangeTypeIndexPaths[rangeKey] mutableCopy] : [NSMutableSet set];

AsyncDisplayKit/Details/ASRangeControllerBeta.mm

@@ -10,6 +10,7 @@
 
 #import "ASAssert.h"
 #import "ASDisplayNodeExtras.h"
+#import "ASDisplayNodeInternal.h"
 #import "ASMultiDimensionalArrayUtils.h"
 #import "ASRangeHandlerVisible.h"
 #import "ASRangeHandlerRender.h"
@@ -17,12 +18,6 @@
 #import "ASInternalHelpers.h"
 #import "ASDisplayNode+FrameworkPrivate.h"
 
-typedef NS_ENUM(NSUInteger, ASRangeTypeUsed) {
-    ASRangeTypeUsedNone,
-    ASRangeTypeUsedMinimum,
-    ASRangeTypeUsedFull,
-};
-
 @interface ASRangeControllerBeta ()
 {
   BOOL _rangeIsValid;
@@ -30,7 +25,8 @@ typedef NS_ENUM(NSUInteger, ASRangeTypeUsed) {
   BOOL _layoutControllerImplementsSetVisibleIndexPaths;
   ASScrollDirection _scrollDirection;
   NSSet<NSIndexPath *> *_allPreviousIndexPaths;
-  ASRangeTypeUsed _rangeTypeUsed;
+  ASLayoutRangeMode _currentRangeMode;
+  BOOL _didRegisterForNotifications;
 }
 
 @end
@@ -44,13 +40,41 @@ typedef NS_ENUM(NSUInteger, ASRangeTypeUsed) {
   }
   
   _rangeIsValid = YES;
-  _rangeTypeUsed = ASRangeTypeUsedNone;
+  _currentRangeMode = ASLayoutRangeModeCount;
   
   return self;
 }
 
+- (void)dealloc
+{
+  if (_didRegisterForNotifications) {
+    [[NSNotificationCenter defaultCenter] removeObserver:self];
+  }
+}
+
 #pragma mark - Core visible node range managment API
 
++ (ASLayoutRangeMode)rangeModeForInterfaceState:(ASInterfaceState)interfaceState
+                                scrollDirection:(ASScrollDirection)scrollDirection
+                               currentRangeMode:(ASLayoutRangeMode)currentRangeMode
+{
+  // If we used full mode, don't switch to minimum mode. That will destroy all the hard work done before.
+  if (currentRangeMode == ASLayoutRangeModeFull) {
+    return ASLayoutRangeModeFull;
+  }
+  
+  BOOL isVisible = (ASInterfaceStateIncludesVisible(interfaceState));
+  BOOL isScrolling = (scrollDirection != ASScrollDirectionNone);
+  BOOL isUsingMinimumRangeMode = (currentRangeMode == ASLayoutRangeModeMinimum);
+  // If we are already visible and scrolling, get busy!  Better get started on preloading before the user scrolls more...
+  // If we are already visible and finished displaying minimum mode, extend to full mode
+  if (isVisible && (isScrolling || isUsingMinimumRangeMode)) {
+    return ASLayoutRangeModeFull;
+  }
+  
+  return ASLayoutRangeModeMinimum;
+}
+
 - (void)visibleNodeIndexPathsDidChangeWithScrollDirection:(ASScrollDirection)scrollDirection
 {
   _scrollDirection = scrollDirection;
@@ -117,25 +141,25 @@ typedef NS_ENUM(NSUInteger, ASRangeTypeUsed) {
   NSMutableOrderedSet<NSIndexPath *> *allIndexPaths = [[NSMutableOrderedSet alloc] initWithSet:visibleIndexPaths];
   
   ASInterfaceState selfInterfaceState = [_dataSource interfaceStateForRangeController:self];
-  BOOL selfIsVisible = (ASInterfaceStateIncludesVisible(selfInterfaceState));
-  BOOL selfIsScrolling = (_scrollDirection != ASScrollDirectionNone);
-  BOOL didUseMinimumRange = (_rangeTypeUsed == ASRangeTypeUsedMinimum);
-  BOOL didUseFullRange  = (_rangeTypeUsed == ASRangeTypeUsedFull);
-  // If we are already visible and scrolling, get busy!  Better get started on preloading before the user scrolls more...
-  // If we are already visible and did finish displaying minimum range, extend to full range
-  // If we used full range, don't switch to minimum range now. That will destroy all the hard work done before.
-  BOOL useFullRange = ((selfIsVisible && (selfIsScrolling || didUseMinimumRange)) || didUseFullRange);
-  NSLog(@"%@ range: %@", useFullRange ? @"Full" : @"Minimum", [((ASCollectionView *)_delegate).asyncDelegate description]);
+  ASLayoutRangeMode rangeMode = [ASRangeControllerBeta rangeModeForInterfaceState:selfInterfaceState
+                                                                  scrollDirection:_scrollDirection
+                                                                 currentRangeMode:_currentRangeMode];
 
-  fetchDataIndexPaths = [_layoutController indexPathsForScrolling:_scrollDirection rangeType:ASLayoutRangeTypeFetchData shouldUseFullRange:useFullRange];
+  fetchDataIndexPaths = [_layoutController indexPathsForScrolling:_scrollDirection
+                                                        rangeMode:rangeMode
+                                                        rangeType:ASLayoutRangeTypeFetchData];
 
-  ASRangeTuningParameters parametersDisplay = [_layoutController tuningParametersForRangeType:ASLayoutRangeTypeDisplay isFullRange:useFullRange];
-  ASRangeTuningParameters parametersFetchData = [_layoutController tuningParametersForRangeType:ASLayoutRangeTypeFetchData isFullRange:useFullRange];
+  ASRangeTuningParameters parametersDisplay = [_layoutController tuningParametersForRangeMode:rangeMode
+                                                                                    rangeType:ASLayoutRangeTypeDisplay];
+  ASRangeTuningParameters parametersFetchData = [_layoutController tuningParametersForRangeMode:rangeMode
+                                                                                      rangeType:ASLayoutRangeTypeFetchData];
   if (parametersDisplay.leadingBufferScreenfuls == parametersFetchData.leadingBufferScreenfuls &&
       parametersDisplay.trailingBufferScreenfuls == parametersFetchData.trailingBufferScreenfuls) {
     displayIndexPaths = fetchDataIndexPaths;
   } else {
-    displayIndexPaths = [_layoutController indexPathsForScrolling:_scrollDirection rangeType:ASLayoutRangeTypeDisplay shouldUseFullRange:useFullRange];
+    displayIndexPaths = [_layoutController indexPathsForScrolling:_scrollDirection
+                                                        rangeMode:rangeMode
+                                                        rangeType:ASLayoutRangeTypeDisplay];
   }
   
   // Typically the fetchDataIndexPaths will be the largest, and be a superset of the others, though it may be disjoint.
@@ -151,12 +175,14 @@ typedef NS_ENUM(NSUInteger, ASRangeTypeUsed) {
   NSSet<NSIndexPath *> *allCurrentIndexPaths = [[allIndexPaths set] copy];
   [allIndexPaths unionSet:_allPreviousIndexPaths];
   _allPreviousIndexPaths = allCurrentIndexPaths;
-  _rangeTypeUsed = useFullRange ? ASRangeTypeUsedFull : ASRangeTypeUsedMinimum;
+  _currentRangeMode = rangeMode;
   
   if (!_rangeIsValid) {
     [allIndexPaths addObjectsFromArray:ASIndexPathsForMultidimensionalArray(allNodes)];
   }
 
+  [self registerForNotificationsIfNeeded];
+  
   // This array is only used if logging is enabled.
   NSMutableArray<NSIndexPath *> *modifiedIndexPaths = (RangeControllerLoggingEnabled ? [NSMutableArray array] : nil);
   
@@ -240,6 +266,33 @@ typedef NS_ENUM(NSUInteger, ASRangeTypeUsed) {
 #endif
 }
 
+#pragma mark - Notification observers
+
+- (void)registerForNotificationsIfNeeded
+{
+  if (!_didRegisterForNotifications) {
+    BOOL selfInterfaceState = [_dataSource interfaceStateForRangeController:self];
+    ASLayoutRangeMode nextRangeMode = [ASRangeControllerBeta rangeModeForInterfaceState:selfInterfaceState
+                                                                        scrollDirection:_scrollDirection
+                                                                       currentRangeMode:_currentRangeMode];
+    if (_currentRangeMode != nextRangeMode) {
+      [[NSNotificationCenter defaultCenter] addObserver:self
+                                               selector:@selector(scheduledNodesDidDisplay)
+                                                   name:ASRenderingEngineDidDisplayScheduledNodesNotification
+                                                 object:nil];
+      _didRegisterForNotifications = YES;
+    }
+  }
+}
+
+- (void)scheduledNodesDidDisplay
+{
+  [[NSNotificationCenter defaultCenter] removeObserver:self];
+  _didRegisterForNotifications = NO;
+
+  [self scheduleRangeUpdate];
+}
+
 #pragma mark - Cell node view handling
 
 - (void)configureContentView:(UIView *)contentView forCellNode:(ASCellNode *)node

AsyncDisplayKit/Private/ASDisplayNodeInternal.h

@@ -37,6 +37,8 @@ typedef NS_OPTIONS(NSUInteger, ASDisplayNodeMethodOverrides)
 @class _ASPendingState;
 @class _ASDisplayNodePosition;
 
+FOUNDATION_EXPORT NSString * const ASRenderingEngineDidDisplayScheduledNodesNotification;
+
 // Allow 2^n increments of begin disabling hierarchy notifications
 #define VISIBILITY_NOTIFICATIONS_DISABLED_BITS 4