Functioning Preload range

Refactor how we do ranges so they can be arbitrarily managed. Introduce the concept of a preload range.

AsyncDisplayKit.xcodeproj/project.pbxproj

@@ -138,6 +138,12 @@
 		05F20AA41A15733C00DCA68A /* ASImageProtocols.h in Headers */ = {isa = PBXBuildFile; fileRef = 05F20AA31A15733C00DCA68A /* ASImageProtocols.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		1950C4491A3BB5C1005C8279 /* ASEqualityHelpers.h in Headers */ = {isa = PBXBuildFile; fileRef = 1950C4481A3BB5C1005C8279 /* ASEqualityHelpers.h */; };
 		2911485C1A77147A005D0878 /* ASControlNodeTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 2911485B1A77147A005D0878 /* ASControlNodeTests.m */; };
+		292C599F1A956527007E5DD6 /* ASLayoutRangeType.h in Headers */ = {isa = PBXBuildFile; fileRef = 292C59991A956527007E5DD6 /* ASLayoutRangeType.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		292C59A01A956527007E5DD6 /* ASPreloadRangeDelegate.h in Headers */ = {isa = PBXBuildFile; fileRef = 292C599A1A956527007E5DD6 /* ASPreloadRangeDelegate.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		292C59A11A956527007E5DD6 /* ASPreloadRangeDelegate.mm in Sources */ = {isa = PBXBuildFile; fileRef = 292C599B1A956527007E5DD6 /* ASPreloadRangeDelegate.mm */; };
+		292C59A21A956527007E5DD6 /* ASRangeDelegate.h in Headers */ = {isa = PBXBuildFile; fileRef = 292C599C1A956527007E5DD6 /* ASRangeDelegate.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		292C59A31A956527007E5DD6 /* ASRenderRangeDelegate.h in Headers */ = {isa = PBXBuildFile; fileRef = 292C599D1A956527007E5DD6 /* ASRenderRangeDelegate.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		292C59A41A956527007E5DD6 /* ASRenderRangeDelegate.mm in Sources */ = {isa = PBXBuildFile; fileRef = 292C599E1A956527007E5DD6 /* ASRenderRangeDelegate.mm */; };
 		3C9C128519E616EF00E942A0 /* ASTableViewTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 3C9C128419E616EF00E942A0 /* ASTableViewTests.m */; settings = {COMPILER_FLAGS = "-fno-objc-arc"; }; };
 		464052201A3F83C40061C0BA /* ASDataController.h in Headers */ = {isa = PBXBuildFile; fileRef = 464052191A3F83C40061C0BA /* ASDataController.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		464052211A3F83C40061C0BA /* ASDataController.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4640521A1A3F83C40061C0BA /* ASDataController.mm */; };
@@ -284,6 +290,12 @@
 		05F20AA31A15733C00DCA68A /* ASImageProtocols.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASImageProtocols.h; sourceTree = "<group>"; };
 		1950C4481A3BB5C1005C8279 /* ASEqualityHelpers.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASEqualityHelpers.h; sourceTree = "<group>"; };
 		2911485B1A77147A005D0878 /* ASControlNodeTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ASControlNodeTests.m; sourceTree = "<group>"; };
+		292C59991A956527007E5DD6 /* ASLayoutRangeType.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASLayoutRangeType.h; sourceTree = "<group>"; };
+		292C599A1A956527007E5DD6 /* ASPreloadRangeDelegate.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASPreloadRangeDelegate.h; sourceTree = "<group>"; };
+		292C599B1A956527007E5DD6 /* ASPreloadRangeDelegate.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASPreloadRangeDelegate.mm; sourceTree = "<group>"; };
+		292C599C1A956527007E5DD6 /* ASRangeDelegate.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASRangeDelegate.h; sourceTree = "<group>"; };
+		292C599D1A956527007E5DD6 /* ASRenderRangeDelegate.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASRenderRangeDelegate.h; sourceTree = "<group>"; };
+		292C599E1A956527007E5DD6 /* ASRenderRangeDelegate.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASRenderRangeDelegate.mm; sourceTree = "<group>"; };
 		3C9C128419E616EF00E942A0 /* ASTableViewTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ASTableViewTests.m; sourceTree = "<group>"; };
 		464052191A3F83C40061C0BA /* ASDataController.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASDataController.h; sourceTree = "<group>"; };
 		4640521A1A3F83C40061C0BA /* ASDataController.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASDataController.mm; sourceTree = "<group>"; };
@@ -463,12 +475,21 @@
 				058D09E7195D050800B7D73C /* ASHighlightOverlayLayer.mm */,
 				05F20AA31A15733C00DCA68A /* ASImageProtocols.h */,
 				4640521D1A3F83C40061C0BA /* ASLayoutController.h */,
+
+				292C59991A956527007E5DD6 /* ASLayoutRangeType.h */,
 				4640521E1A3F83C40061C0BA /* ASMultidimensionalArrayUtils.h */,
 				4640521F1A3F83C40061C0BA /* ASMultidimensionalArrayUtils.mm */,
 				058D09E8195D050800B7D73C /* ASMutableAttributedStringBuilder.h */,
 				058D09E9195D050800B7D73C /* ASMutableAttributedStringBuilder.m */,
 				055F1A3619ABD413004DAFF1 /* ASRangeController.h */,
 				055F1A3719ABD413004DAFF1 /* ASRangeController.mm */,
+				292C599A1A956527007E5DD6 /* ASPreloadRangeDelegate.h */,
+				292C599B1A956527007E5DD6 /* ASPreloadRangeDelegate.mm */,
+				055F1A3619ABD413004DAFF1 /* ASRangeController.h */,
+				055F1A3719ABD413004DAFF1 /* ASRangeController.mm */,
+				292C599C1A956527007E5DD6 /* ASRangeDelegate.h */,
+				292C599D1A956527007E5DD6 /* ASRenderRangeDelegate.h */,
+				292C599E1A956527007E5DD6 /* ASRenderRangeDelegate.mm */,
 				058D09EA195D050800B7D73C /* ASTextNodeCoreTextAdditions.h */,
 				058D09EB195D050800B7D73C /* ASTextNodeCoreTextAdditions.m */,
 				058D09EC195D050800B7D73C /* ASTextNodeRenderer.h */,
@@ -574,6 +595,7 @@
 				058D0A51195D05CB00B7D73C /* ASTextNode.h in Headers */,
 				058D0A52195D05CB00B7D73C /* ASTextNode.mm in Headers */,
 				055F1A3819ABD413004DAFF1 /* ASRangeController.h in Headers */,
+				292C59A31A956527007E5DD6 /* ASRenderRangeDelegate.h in Headers */,
 				055F1A3419ABD3E3004DAFF1 /* ASTableView.h in Headers */,
 				0574D5E219C110940097DC25 /* ASTableViewProtocols.h in Headers */,
 				055F1A3C19ABD43F004DAFF1 /* ASCellNode.h in Headers */,
@@ -594,6 +616,7 @@
 				058D0A61195D05DC00B7D73C /* ASTextNodeTextKitHelpers.h in Headers */,
 				058D0A62195D05DC00B7D73C /* ASTextNodeTextKitHelpers.mm in Headers */,
 				058D0A63195D05DC00B7D73C /* ASTextNodeTypes.h in Headers */,
+				292C599F1A956527007E5DD6 /* ASLayoutRangeType.h in Headers */,
 				464052251A3F83C40061C0BA /* ASMultidimensionalArrayUtils.h in Headers */,
 				058D0A64195D05DC00B7D73C /* ASTextNodeWordKerner.h in Headers */,
 				058D0A65195D05DC00B7D73C /* ASTextNodeWordKerner.m in Headers */,
@@ -615,6 +638,7 @@
 				058D0A83195D060300B7D73C /* ASBaseDefines.h in Headers */,
 				058D0A84195D060300B7D73C /* ASDisplayNodeExtraIvars.h in Headers */,
 				AC3C4A511A1139C100143C57 /* ASCollectionView.h in Headers */,
+				292C59A01A956527007E5DD6 /* ASPreloadRangeDelegate.h in Headers */,
 				055B9FA81A1C154B00035D6D /* ASNetworkImageNode.h in Headers */,
 				054963491A1EA066000F8E56 /* ASBasicImageDownloader.h in Headers */,
 				AC3C4A541A113EEC00143C57 /* ASCollectionViewProtocols.h in Headers */,
@@ -634,6 +658,7 @@
 				058D0A7B195D05F900B7D73C /* ASDisplayNodeInternal.h in Headers */,
 				058D0A7C195D05F900B7D73C /* ASImageNode+CGExtras.h in Headers */,
 				058D0A7D195D05F900B7D73C /* ASImageNode+CGExtras.m in Headers */,
+				292C59A21A956527007E5DD6 /* ASRangeDelegate.h in Headers */,
 				058D0A7F195D05F900B7D73C /* ASSentinel.h in Headers */,
 				058D0A80195D05F900B7D73C /* ASSentinel.m in Headers */,
 				058D0A81195D05F900B7D73C /* ASThread.h in Headers */,
@@ -770,8 +795,10 @@
 				464052261A3F83C40061C0BA /* ASMultidimensionalArrayUtils.mm in Sources */,
 				055B9FA91A1C154B00035D6D /* ASNetworkImageNode.mm in Sources */,
 				058D0A1D195D050800B7D73C /* ASTextNodeRenderer.mm in Sources */,
+				292C59A41A956527007E5DD6 /* ASRenderRangeDelegate.mm in Sources */,
 				058D0A2A195D050800B7D73C /* ASDisplayNode+UIViewBridge.mm in Sources */,
 				AC3C4A521A1139C100143C57 /* ASCollectionView.mm in Sources */,
+				292C59A11A956527007E5DD6 /* ASPreloadRangeDelegate.mm in Sources */,
 				058D0A20195D050800B7D73C /* ASTextNodeWordKerner.m in Sources */,
 				058D0A1A195D050800B7D73C /* ASHighlightOverlayLayer.mm in Sources */,
 				464052231A3F83C40061C0BA /* ASFlowLayoutController.mm in Sources */,

AsyncDisplayKit/ASCollectionView.h

@@ -39,7 +39,7 @@
  * Defaults to the render range having one sceenful both leading and trailing and the preload range having two
  * screenfuls in both directions.
  */
-- (ASRangeTuningParameters)tuningParametersForRange:(ASLayoutRange)range;
+- (ASRangeTuningParameters)tuningParametersForRangeType:(ASLayoutRangeType)rangeType;
 
 /**
  * Set the tuning parameters for a range.
@@ -47,7 +47,7 @@
  * @param tuningParameters The tuning parameters to store for a range.
  * @param range The range to set the tuning parameters for.
  */
-- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRange:(ASLayoutRange)range;
+- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeType:(ASLayoutRangeType)rangeType;
 
 /**
  * Initializer.

AsyncDisplayKit/ASCollectionView.mm

@@ -199,24 +199,24 @@ static BOOL _isInterceptedSelector(SEL sel)
   super.delegate = (id<UICollectionViewDelegate>)_proxyDelegate;
 }
 
-- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRange:(ASLayoutRange)range
+- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeType:(ASLayoutRangeType)rangeType
 {
-  [_layoutController setTuningParameters:tuningParameters forRange:range];
+  [_layoutController setTuningParameters:tuningParameters forRangeType:rangeType];
 }
 
-- (ASRangeTuningParameters)tuningParametersForRange:(ASLayoutRange)range
+- (ASRangeTuningParameters)tuningParametersForRangeType:(ASLayoutRangeType)rangeType
 {
-  return [_layoutController tuningParametersForRange:range];
+  return [_layoutController tuningParametersForRangeType:rangeType];
 }
 
 - (ASRangeTuningParameters)rangeTuningParameters
 {
-  return [self tuningParametersForRange:ASLayoutRangeRender];
+  return [self tuningParametersForRangeType:ASLayoutRangeTypeRender];
 }
 
 - (void)setRangeTuningParameters:(ASRangeTuningParameters)tuningParameters
 {
-  [self setTuningParameters:tuningParameters forRange:ASLayoutRangeRender];
+  [self setTuningParameters:tuningParameters forRangeType:ASLayoutRangeTypeRender];
 }
 
 - (CGSize)calculatedSizeForNodeAtIndexPath:(NSIndexPath *)indexPath

AsyncDisplayKit/ASDisplayNode+Subclasses.h

@@ -185,6 +185,14 @@
  */
 - (void)displayDidFinish ASDISPLAYNODE_REQUIRES_SUPER;
 
+/**
+ * @abstract Indicates that the node should fetch any external data, such as images.
+ *
+ * @discussion Subclasses may override this method to be notified when they should begin to fetch data. Fetching
+ * should be done asynchronously. The node is also responsible for managing the memory of any data.
+ */
+- (void)fetchRemoteData ASDISPLAYNODE_REQUIRES_SUPER;
+
 /**
  * @abstract Indicates that the receiver is about to display its subnodes. This method is not called if there are no
  * subnodes present.
@@ -312,13 +320,20 @@
 - (void)didExitHierarchy ASDISPLAYNODE_REQUIRES_SUPER;
 
 /**
- * Provides an opportunity to clear backing store and other memory-intensive intermediates, such as text layout managers
+ * Provides an opportunity to clear backing store and other memory-intensive intermediates, such as text layout managers.
- * or downloaded content that can be written to a disk cache.
  *
- * @discussion Called by -recursivelyReclaimMemory.   Base class implements self.contents = nil, clearing any backing
+ * @discussion Called by -recursivelyClearRendering. Base class implements self.contents = nil, clearing any backing
  * store, for asynchronous regeneration when needed.
  */
-- (void)reclaimMemory ASDISPLAYNODE_REQUIRES_SUPER;
+- (void)clearRendering ASDISPLAYNODE_REQUIRES_SUPER;
+
+/**
+ * Provides an opportunity to clear any remote data for only the current node.
+ *
+ * @discussion This will not clear data recursively for all subnodes. Either call -recursivelyClearRemoteData or
+ * selectively clear remote data.
+ */
+- (void)clearRemoteData ASDISPLAYNODE_REQUIRES_SUPER;
 
 
 /** @name Placeholders */

AsyncDisplayKit/ASDisplayNode.h

@@ -312,7 +312,7 @@ typedef CALayer *(^ASDisplayNodeLayerBlock)();
 - (void)recursivelySetDisplaySuspended:(BOOL)flag;
 
 /**
- * @abstract Calls -reclaimMemory on the receiver and its subnode hierarchy.
+ * @abstract Calls -clearRendering on the receiver and its subnode hierarchy.
  *
  * @discussion Clears backing stores and other memory-intensive intermediates.
  * If the node is removed from a visible hierarchy and then re-added, it will automatically trigger a new asynchronous display,
@@ -322,7 +322,18 @@ typedef CALayer *(^ASDisplayNodeLayerBlock)();
  * @see displaySuspended and setNeedsDisplay
  */
 
-- (void)recursivelyReclaimMemory;
+- (void)recursivelyClearRendering;
+
+/**
+ * @abstract Calls -clearRemoteData on the receiver and its subnode hierarchy.
+ *
+ * @discussion Clears any memory-intensive fetched content.
+ * This method is used to notify the node that it should purge any content that is both expensive to fetch and to
+ * retain in memory.
+ *
+ * @see fetchRemoteData
+ */
+- (void)recursivelyClearRemoteData;
 
 /**
  * @abstract Toggle displaying a placeholder over the node that covers content until the node and all subnodes are
@@ -539,5 +550,9 @@ typedef CALayer *(^ASDisplayNodeLayerBlock)();
 @end
 
 @interface ASDisplayNode (Deprecated)
+
+- (void)reclaimMemory ASDISPLAYNODE_DEPRECATED;
+- (void)recursivelyReclaimMemory ASDISPLAYNODE_DEPRECATED;
 @property (nonatomic, assign) BOOL placeholderFadesOut ASDISPLAYNODE_DEPRECATED;
+
 @end

AsyncDisplayKit/ASDisplayNode.mm

@@ -90,7 +90,7 @@ void ASDisplayNodePerformBlockOnMainThread(void (^block)())
   // Subclasses should never override these
   ASDisplayNodeAssert(!ASDisplayNodeSubclassOverridesSelector(self, @selector(calculatedSize)), @"Subclass %@ must not override calculatedSize method", NSStringFromClass(self));
   ASDisplayNodeAssert(!ASDisplayNodeSubclassOverridesSelector(self, @selector(measure:)), @"Subclass %@ must not override measure method", NSStringFromClass(self));
-  ASDisplayNodeAssert(!ASDisplayNodeSubclassOverridesSelector(self, @selector(recursivelyReclaimMemory)), @"Subclass %@ must not override recursivelyReclaimMemory method", NSStringFromClass(self));
+  ASDisplayNodeAssert(!ASDisplayNodeSubclassOverridesSelector(self, @selector(recursivelyClearRendering)), @"Subclass %@ must not override recursivelyClearRendering method", NSStringFromClass(self));
 }
 
 + (BOOL)layerBackedNodesEnabled
@@ -1328,18 +1328,36 @@ static NSInteger incrementIfFound(NSInteger i) {
   [self __exitedHierarchy];
 }
 
-- (void)reclaimMemory
+- (void)clearRendering
 {
   self.layer.contents = nil;
   _placeholderLayer.contents = nil;
 }
 
-- (void)recursivelyReclaimMemory
+- (void)recursivelyClearRendering
 {
   for (ASDisplayNode *subnode in self.subnodes) {
-    [subnode recursivelyReclaimMemory];
+    [subnode recursivelyClearRendering];
   }
-  [self reclaimMemory];
+  [self clearRendering];
+}
+
+- (void)fetchRemoteData
+{
+  // subclass override
+}
+
+- (void)clearRemoteData
+{
+  // subclass override
+}
+
+- (void)recursivelyClearRemoteData
+{
+  for (ASDisplayNode *subnode in self.subnodes) {
+    [subnode recursivelyClearRemoteData];
+  }
+  [self clearRemoteData];
 }
 
 - (void)layout
@@ -1460,6 +1478,7 @@ static NSInteger incrementIfFound(NSInteger i) {
   }
 }
 
+
 #pragma mark - Pending View State
 - (_ASPendingState *)pendingViewState
 {
@@ -1786,4 +1805,14 @@ static const char *ASDisplayNodeAssociatedNodeKey = "ASAssociatedNode";
   return self.placeholderFadeDuration > 0.0;
 }
 
+- (void)reclaimMemory
+{
+  [self clearRendering];
+}
+
+- (void)recursivelyReclaimMemory
+{
+  [self recursivelyClearRendering];
+}
+
 @end

AsyncDisplayKit/ASMultiplexImageNode.mm

@@ -162,9 +162,9 @@ typedef void(^ASMultiplexImageLoadCompletionBlock)(UIImage *image, id imageIdent
 }
 
 #pragma mark - ASDisplayNode Overrides
-- (void)reclaimMemory
+- (void)clearRendering
 {
-  [super reclaimMemory]; // This actually clears the contents, so we need to do this first for our displayedImageIdentifier to be meaningful.
+  [super clearRendering]; // This actually clears the contents, so we need to do this first for our displayedImageIdentifier to be meaningful.
   [self _setDisplayedImageIdentifier:nil withImage:nil];
 
   if (_downloadIdentifier) {
@@ -177,6 +177,13 @@ typedef void(^ASMultiplexImageLoadCompletionBlock)(UIImage *image, id imageIdent
 {
   [super displayWillStart];
 
+  [self fetchRemoteData];
+}
+
+- (void)fetchRemoteData
+{
+  [super fetchRemoteData];
+
   [self _loadImageIdentifiers];
 }
 

AsyncDisplayKit/ASNetworkImageNode.mm

@@ -123,9 +123,16 @@
   return _delegate;
 }
 
-- (void)reclaimMemory
+- (void)displayWillStart
 {
-  [super reclaimMemory];
+  [super displayWillStart];
+
+  [self fetchRemoteData];
+}
+
+- (void)clearRemoteData
+{
+  [super clearRemoteData];
 
   {
     ASDN::MutexLocker l(_lock);
@@ -136,10 +143,10 @@
   }
 }
 
-- (void)displayWillStart
+- (void)fetchRemoteData
 {
-  [super displayWillStart];
+  [super fetchRemoteData];
-
+  
   {
     ASDN::MutexLocker l(_lock);
     [self _lazilyLoadImageIfNecessary];

AsyncDisplayKit/ASTableView.h

@@ -32,22 +32,22 @@
 /**
  * Tuning parameters for a range.
  *
- * @param range The range to get the tuning parameters for.
+ * @param rangeType The range to get the tuning parameters for.
  *
  * @returns A tuning parameter value for the given range.
  *
  * Defaults to the render range having one sceenful both leading and trailing and the preload range having two 
  * screenfuls in both directions.
  */
-- (ASRangeTuningParameters)tuningParametersForRange:(ASLayoutRange)range;
+- (ASRangeTuningParameters)tuningParametersForRangeType:(ASLayoutRangeType)rangeType;
 
 /**
  * Set the tuning parameters for a range.
  *
  * @param tuningParameters The tuning parameters to store for a range.
- * @param range The range to set the tuning parameters for.
+ * @param rangeType The range to set the tuning parameters for.
  */
-- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRange:(ASLayoutRange)range;
+- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeType:(ASLayoutRangeType)rangeType;
 
 /**
  * initializer.

AsyncDisplayKit/ASTableView.mm

@@ -201,24 +201,24 @@ static BOOL _isInterceptedSelector(SEL sel)
   [_dataController reloadDataWithAnimationOption:UITableViewRowAnimationNone];
 }
 
-- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRange:(ASLayoutRange)range
+- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeType:(ASLayoutRangeType)rangeType
 {
-  [_layoutController setTuningParameters:tuningParameters forRange:range];
+  [_layoutController setTuningParameters:tuningParameters forRangeType:rangeType];
 }
 
-- (ASRangeTuningParameters)tuningParametersForRange:(ASLayoutRange)range
+- (ASRangeTuningParameters)tuningParametersForRangeType:(ASLayoutRangeType)rangeType
 {
-  return [_layoutController tuningParametersForRange:range];
+  return [_layoutController tuningParametersForRangeType:rangeType];
 }
 
 - (ASRangeTuningParameters)rangeTuningParameters
 {
-  return [self tuningParametersForRange:ASLayoutRangeRender];
+  return [self tuningParametersForRangeType:ASLayoutRangeTypeRender];
 }
 
 - (void)setRangeTuningParameters:(ASRangeTuningParameters)tuningParameters
 {
-  [self setTuningParameters:tuningParameters forRange:ASLayoutRangeRender];
+  [self setTuningParameters:tuningParameters forRangeType:ASLayoutRangeTypeRender];
 }
 
 - (ASCellNode *)nodeForRowAtIndexPath:(NSIndexPath *)indexPath

AsyncDisplayKit/ASTextNode.mm

@@ -212,12 +212,12 @@ ASDISPLAYNODE_INLINE CGFloat ceilPixelValue(CGFloat f)
   [self _invalidateRenderer];
 }
 
-- (void)reclaimMemory
+- (void)clearRendering
 {
   // We discard the backing store and renderer to prevent the very large
   // memory overhead of maintaining these for all text nodes.  They can be
   // regenerated when layout is necessary.
-  [super reclaimMemory];      // ASDisplayNode will set layer.contents = nil
+  [super clearRendering];      // ASDisplayNode will set layer.contents = nil
   [self _invalidateRenderer];
 }
 

AsyncDisplayKit/Details/ASDataController.h

@@ -1,4 +1,10 @@
-//  Copyright 2004-present Facebook. All Rights Reserved.
+/* Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
 
 #import <UIKit/UIKit.h>
 #import <AsyncDisplayKit/ASDealloc2MainObject.h>

AsyncDisplayKit/Details/ASDataController.mm

@@ -1,4 +1,10 @@
-//  Copyright 2004-present Facebook. All Rights Reserved.
+/* Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
 
 #import "ASDataController.h"
 

AsyncDisplayKit/Details/ASFlowLayoutController.h

@@ -1,4 +1,10 @@
-//  Copyright 2004-present Facebook. All Rights Reserved.
+/* Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
 
 #import <AsyncDisplayKit/ASLayoutController.h>
 #import <AsyncDisplayKit/ASBaseDefines.h>
@@ -14,9 +20,9 @@ typedef NS_ENUM(NSUInteger, ASFlowLayoutDirection) {
  */
 @interface ASFlowLayoutController : NSObject <ASLayoutController>
 
-- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRange:(ASLayoutRange)range;
+- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeType:(ASLayoutRangeType)rangeType;
 
-- (ASRangeTuningParameters)tuningParametersForRange:(ASLayoutRange)range;
+- (ASRangeTuningParameters)tuningParametersForRangeType:(ASLayoutRangeType)rangeType;
 
 @property (nonatomic, readonly, assign) ASFlowLayoutDirection layoutDirection;
 

AsyncDisplayKit/Details/ASFlowLayoutController.mm

@@ -1,4 +1,10 @@
-//  Copyright 2004-present Facebook. All Rights Reserved.
+/* Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
 
 #import "ASFlowLayoutController.h"
 
@@ -33,17 +39,14 @@ static const CGFloat kASFlowLayoutControllerRefreshingThreshold = 0.3;
 
   _layoutDirection = layoutDirection;
 
-  _tuningParameterMap = {
+  _tuningParameterMap = std::vector<ASRangeTuningParameters>(2);
-    {
+  _tuningParameterMap[ASLayoutRangeTypePreload] = {
-      // Render
+    .leadingBufferScreenfuls = 2,
-      .leadingBufferScreenfuls = 1,
+    .trailingBufferScreenfuls = 1
-      .trailingBufferScreenfuls = 1
+  };
-    },
+  _tuningParameterMap[ASLayoutRangeTypeRender] = {
-    {
+    .leadingBufferScreenfuls = 3,
-      // Preload
+    .trailingBufferScreenfuls = 2
-      .leadingBufferScreenfuls = 2,
-      .trailingBufferScreenfuls = 2
-    }
   };
 
   return self;
@@ -51,28 +54,28 @@ static const CGFloat kASFlowLayoutControllerRefreshingThreshold = 0.3;
 
 #pragma mark - Tuning Parameters
 
-- (ASRangeTuningParameters)tuningParametersForRange:(ASLayoutRange)range
+- (ASRangeTuningParameters)tuningParametersForRangeType:(ASLayoutRangeType)rangeType
 {
-  ASDisplayNodeAssert(range < _tuningParameterMap.size(), @"Requesting a range that is OOB for the configured tuning parameters");
+  ASDisplayNodeAssert(rangeType < _tuningParameterMap.size(), @"Requesting a range that is OOB for the configured tuning parameters");
-  return _tuningParameterMap[range];
+  return _tuningParameterMap[rangeType];
 }
 
-- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRange:(ASLayoutRange)range
+- (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters forRangeType:(ASLayoutRangeType)rangeType
 {
-  ASDisplayNodeAssert(range < _tuningParameterMap.size(), @"Requesting a range that is OOB for the configured tuning parameters");
+  ASDisplayNodeAssert(rangeType < _tuningParameterMap.size(), @"Requesting a range that is OOB for the configured tuning parameters");
-  _tuningParameterMap[range] = tuningParameters;
+  _tuningParameterMap[rangeType] = tuningParameters;
 }
 
 // Support for the deprecated tuningParameters property
 - (ASRangeTuningParameters)tuningParameters
 {
-  return [self tuningParametersForRange:ASLayoutRangeRender];
+  return [self tuningParametersForRangeType:ASLayoutRangeTypeRender];
 }
 
 // Support for the deprecated tuningParameters property
 - (void)setTuningParameters:(ASRangeTuningParameters)tuningParameters
 {
-  [self setTuningParameters:tuningParameters forRange:ASLayoutRangeRender];
+  [self setTuningParameters:tuningParameters forRangeType:ASLayoutRangeTypeRender];
 }
 
 #pragma mark - Editing
@@ -120,7 +123,7 @@ static const CGFloat kASFlowLayoutControllerRefreshingThreshold = 0.3;
 
 #pragma mark - Visible Indices
 
-- (BOOL)shouldUpdateForVisibleIndexPaths:(NSArray *)indexPaths viewportSize:(CGSize)viewportSize range:(ASLayoutRange)range
+- (BOOL)shouldUpdateForVisibleIndexPaths:(NSArray *)indexPaths viewportSize:(CGSize)viewportSize rangeType:(ASLayoutRangeType)rangeType
 {
   if (!indexPaths.count) {
     return NO;
@@ -128,9 +131,9 @@ static const CGFloat kASFlowLayoutControllerRefreshingThreshold = 0.3;
 
   std::pair<int, int> rangeStartPos, rangeEndPos;
 
-  if (range < _rangeStartPos.size() && range < _rangeEndPos.size()) {
+  if (rangeType < _rangeStartPos.size() && rangeType < _rangeEndPos.size()) {
-    rangeStartPos = _rangeStartPos[range];
+    rangeStartPos = _rangeStartPos[rangeType];
-    rangeEndPos = _rangeEndPos[range];
+    rangeEndPos = _rangeEndPos[rangeType];
   }
 
   std::pair<int, int> startPos, endPos;
@@ -147,7 +150,7 @@ static const CGFloat kASFlowLayoutControllerRefreshingThreshold = 0.3;
 - (BOOL)shouldUpdateForVisibleIndexPath:(NSArray *)indexPaths
                                         viewportSize:(CGSize)viewportSize
 {
-  return [self shouldUpdateForVisibleIndexPaths:indexPaths viewportSize:viewportSize range:ASLayoutRangeRender];
+  return [self shouldUpdateForVisibleIndexPaths:indexPaths viewportSize:viewportSize rangeType:ASLayoutRangeTypeRender];
 }
 
 - (void)setVisibleNodeIndexPaths:(NSArray *)indexPaths
@@ -159,7 +162,7 @@ static const CGFloat kASFlowLayoutControllerRefreshingThreshold = 0.3;
  * IndexPath array for the element in the working range.
  */
 
-- (NSSet *)indexPathsForScrolling:(enum ASScrollDirection)scrollDirection viewportSize:(CGSize)viewportSize range:(ASLayoutRange)range
+- (NSSet *)indexPathsForScrolling:(enum ASScrollDirection)scrollDirection viewportSize:(CGSize)viewportSize rangeType:(ASLayoutRangeType)rangeType
 {
   CGFloat viewportScreenMetric;
   ASScrollDirection leadingDirection;
@@ -176,12 +179,12 @@ static const CGFloat kASFlowLayoutControllerRefreshingThreshold = 0.3;
     leadingDirection = ASScrollDirectionUp;
   }
 
-  ASRangeTuningParameters tuningParameters = [self tuningParametersForRange:range];
+  ASRangeTuningParameters tuningParameters = [self tuningParametersForRangeType:rangeType];
   CGFloat backScreens = scrollDirection == leadingDirection ? tuningParameters.leadingBufferScreenfuls : tuningParameters.trailingBufferScreenfuls;
   CGFloat frontScreens = scrollDirection == leadingDirection ? tuningParameters.trailingBufferScreenfuls : tuningParameters.leadingBufferScreenfuls;
 
-  std::pair<int, int> startIter = ASFindIndexForRange(_nodeSizes, _visibleRangeStartPos, - backScreens * viewportSize.height, _layoutDirection);
+  std::pair<int, int> startIter = ASFindIndexForRange(_nodeSizes, _visibleRangeStartPos, - backScreens * viewportScreenMetric, _layoutDirection);
-  std::pair<int, int> endIter = ASFindIndexForRange(_nodeSizes, _visibleRangeEndPos, frontScreens * viewportSize.height, _layoutDirection);
+  std::pair<int, int> endIter = ASFindIndexForRange(_nodeSizes, _visibleRangeEndPos, frontScreens * viewportScreenMetric, _layoutDirection);
 
   NSMutableSet *indexPathSet = [[NSMutableSet alloc] init];
 
@@ -203,7 +206,7 @@ static const CGFloat kASFlowLayoutControllerRefreshingThreshold = 0.3;
 - (NSSet *)indexPathsForScrolling:(enum ASScrollDirection)scrollDirection
                                  viewportSize:(CGSize)viewportSize
 {
-  return [self indexPathsForScrolling:scrollDirection viewportSize:viewportSize range:ASLayoutRangeRender];
+  return [self indexPathsForScrolling:scrollDirection viewportSize:viewportSize rangeType:ASLayoutRangeTypeRender];
 }
 
 #pragma mark - Utility

AsyncDisplayKit/Details/ASLayoutController.h

@@ -1,8 +1,15 @@
-//  Copyright 2004-present Facebook. All Rights Reserved.
+/* Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
 
 #import <UIKit/UIKit.h>
 
 #import <AsyncDisplayKit/ASBaseDefines.h>
+#import <AsyncDisplayKit/ASLayoutRangeType.h>
 
 typedef struct {
   CGFloat leadingBufferScreenfuls;
@@ -17,11 +24,6 @@ typedef NS_ENUM(NSInteger, ASScrollDirection) {
   ASScrollDirectionDown,
 };
 
-typedef NS_ENUM(NSInteger, ASLayoutRange) {
-  ASLayoutRangeRender,
-  ASLayoutRangePreload
-};
-
 @protocol ASLayoutController <NSObject>
 
 /**
@@ -29,7 +31,7 @@ typedef NS_ENUM(NSInteger, ASLayoutRange) {
  *
  * Defaults to a trailing buffer of one screenful and a leading buffer of two screenfuls.
  */
-- (ASRangeTuningParameters)tuningParametersForRange:(ASLayoutRange)range;
+- (ASRangeTuningParameters)tuningParametersForRangeType:(ASLayoutRangeType)rangeType;
 
 - (void)insertNodesAtIndexPaths:(NSArray *)indexPaths withSizes:(NSArray *)nodeSizes;
 
@@ -41,9 +43,9 @@ typedef NS_ENUM(NSInteger, ASLayoutRange) {
 
 - (void)setVisibleNodeIndexPaths:(NSArray *)indexPaths;
 
-- (BOOL)shouldUpdateForVisibleIndexPaths:(NSArray *)indexPaths viewportSize:(CGSize)viewportSize range:(ASLayoutRange)range;
+- (BOOL)shouldUpdateForVisibleIndexPaths:(NSArray *)indexPaths viewportSize:(CGSize)viewportSize rangeType:(ASLayoutRangeType)rangeType;
 
-- (NSSet *)indexPathsForScrolling:(enum ASScrollDirection)scrollDirection viewportSize:(CGSize)viewportSize range:(ASLayoutRange)range;
+- (NSSet *)indexPathsForScrolling:(enum ASScrollDirection)scrollDirection viewportSize:(CGSize)viewportSize rangeType:(ASLayoutRangeType)rangeType;
 
 @property (nonatomic, assign) ASRangeTuningParameters tuningParameters ASDISPLAYNODE_DEPRECATED;
 

AsyncDisplayKit/Details/ASLayoutRangeType.h

@@ -0,0 +1,15 @@
+/* Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <Foundation/Foundation.h>
+
+typedef NS_ENUM(NSInteger, ASLayoutRangeType) {
+  ASLayoutRangeTypeRender,
+  ASLayoutRangeTypePreload,
+  ASLayoutRangeTypeCount
+};

AsyncDisplayKit/Details/ASMultidimensionalArrayUtils.h

@@ -1,4 +1,10 @@
-//  Copyright 2004-present Facebook. All Rights Reserved.
+/* Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
 
 #import <Foundation/Foundation.h>
 

AsyncDisplayKit/Details/ASMultidimensionalArrayUtils.mm

@@ -1,4 +1,10 @@
-//  Copyright 2004-present Facebook. All Rights Reserved.
+/* Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
 
 #import "ASAssert.h"
 #import "ASMultidimensionalArrayUtils.h"

AsyncDisplayKit/Details/ASPreloadRangeDelegate.h

@@ -0,0 +1,15 @@
+/* Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <Foundation/Foundation.h>
+
+#import <AsyncDisplayKit/ASRangeDelegate.h>
+
+@interface ASPreloadRangeDelegate : NSObject <ASRangeDelegate>
+
+@end

AsyncDisplayKit/Details/ASPreloadRangeDelegate.mm

@@ -0,0 +1,26 @@
+/* Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "ASPreloadRangeDelegate.h"
+
+#import "ASDisplayNode.h"
+#import "ASDisplayNode+Subclasses.h"
+
+@implementation ASPreloadRangeDelegate
+
+- (void)node:(ASDisplayNode *)node enteredRangeType:(ASLayoutRangeType)rangeType
+{
+  [node fetchRemoteData];
+}
+
+- (void)node:(ASDisplayNode *)node exitedRangeType:(ASLayoutRangeType)rangeType
+{
+  [node clearRemoteData];
+}
+
+@end

AsyncDisplayKit/Details/ASRangeController.h

@@ -20,7 +20,7 @@
  * Working range controller.
  *
  * Used internally by ASTableView and potentially by a future ASCollectionView.  Observes the visible range, maintains
- * a working range, and is responsible for handling AsyncDisplayKit machinery (sizing cell nodes, enqueueing and
+ * a working range, and is responsible for handling AsyncDisplayKit machinery (sizing cell nodes,x enqueueing and
  * cancelling their asynchronous layout and display, and so on).
  */
 @interface ASRangeController : ASDealloc2MainObject <ASDataControllerDelegate>

AsyncDisplayKit/Details/ASRangeController.mm

@@ -11,62 +11,16 @@
 #import "ASAssert.h"
 #import "ASDisplayNodeExtras.h"
 #import "ASDisplayNodeInternal.h"
-#import "ASLayoutController.h"
-
 #import "ASMultiDimensionalArrayUtils.h"
-
+#import "ASRenderRangeDelegate.h"
-@interface ASDisplayNode (ASRangeController)
+#import "ASPreloadRangeDelegate.h"
-
-- (void)display;
-- (void)recursivelyDisplay;
-
-@end
-
-@implementation ASDisplayNode (ASRangeController)
-
-- (void)display
-{
-  if (![self __shouldLoadViewOrLayer]) {
-    return;
-  }
-
-  ASDisplayNodeAssertMainThread();
-  ASDisplayNodeAssert(self.nodeLoaded, @"backing store must be loaded before calling -display");
-
-  CALayer *layer = self.layer;
-
-  // rendering a backing store requires a node be laid out
-  [layer setNeedsLayout];
-  [layer layoutIfNeeded];
-
-  if (layer.contents) {
-    return;
-  }
-
-  [layer setNeedsDisplay];
-  [layer displayIfNeeded];
-}
-
-- (void)recursivelyDisplay
-{
-  if (![self __shouldLoadViewOrLayer]) {
-    return;
-  }
-  
-  for (ASDisplayNode *node in self.subnodes) {
-    [node recursivelyDisplay];
-  }
-
-  [self display];
-}
-
-@end
 
 @interface ASRangeController () {
-  NSSet *_workingRangeIndexPaths;
+  BOOL _rangeIsValid;
-  NSSet *_workingRangeNodes;
+
-  BOOL _workingRangeIsValid;
+  // keys should be ASLayoutRangeTypes and values NSSets containing NSIndexPaths
-  
+  NSMutableDictionary *_rangeTypeIndexPaths;
+  NSDictionary *_rangeTypeDelegates;
   BOOL _queuedRangeUpdate;
 
   ASScrollDirection _scrollDirection;
@@ -79,63 +33,32 @@
 - (instancetype)init {
   if (self = [super init]) {
 
-    _workingRangeIndexPaths = [NSSet set];
+    _rangeIsValid = YES;
-    _workingRangeIsValid = YES;
+    _rangeTypeIndexPaths = [[NSMutableDictionary alloc] init];
+
+    _rangeTypeDelegates = @{
+                            @(ASLayoutRangeTypeRender): [[ASRenderRangeDelegate alloc] init],
+                            @(ASLayoutRangeTypePreload): [[ASPreloadRangeDelegate alloc] init],
+                            };
   }
 
   return self;
 }
 
-#pragma mark - View manipulation.
 
-- (void)discardNode:(ASCellNode *)node
+#pragma mark - View manipulation
-{
-  ASDisplayNodeAssertMainThread();
-  ASDisplayNodeAssert(node, @"invalid argument");
-
-  if ([_workingRangeNodes containsObject:node]) {
-    // move the node's view to the working range area, so its rendering persists
-    [self addNodeToWorkingRange:node];
-  } else {
-    // this node isn't in the working range, remove it from the view hierarchy
-    [self removeNodeFromWorkingRange:node];
-  }
-}
-
-- (void)removeNodeFromWorkingRange:(ASCellNode *)node
-{
-  ASDisplayNodeAssertMainThread();
-  ASDisplayNodeAssert(node, @"invalid argument");
-
-  [node recursivelySetDisplaySuspended:YES];
-  [node.view removeFromSuperview];
-
-  // since this class usually manages large or infinite data sets, the working range
-  // directly bounds memory usage by requiring redrawing any content that falls outside the range.
-  [node recursivelyReclaimMemory];
-}
-
-- (void)addNodeToWorkingRange:(ASCellNode *)node
-{
-  ASDisplayNodeAssertMainThread();
-  ASDisplayNodeAssert(node, @"invalid argument");
-
-  // if node is in the working range it should not actively be in view
-  [node.view removeFromSuperview];
-
-  [node recursivelyDisplay];
-}
 
 - (void)moveNode:(ASCellNode *)node toView:(UIView *)view
 {
   ASDisplayNodeAssertMainThread();
-  ASDisplayNodeAssert(node && view, @"invalid argument, did you mean -removeNodeFromWorkingRange:?");
+  ASDisplayNodeAssert(node, @"Cannot move a nil node to a view");
+  ASDisplayNodeAssert(view, @"Cannot move a node to a non-existent view");
 
   [view addSubview:node.view];
 }
 
-#pragma mark -
+
-#pragma mark API.
+#pragma mark - API
 
 - (void)visibleNodeIndexPathsDidChangeWithScrollDirection:(ASScrollDirection)scrollDirection
 {
@@ -159,42 +82,64 @@
     return;
   }
 
-  NSArray *indexPaths = [_delegate rangeControllerVisibleNodeIndexPaths:self];
+  NSArray *visibleNodePaths = [_delegate rangeControllerVisibleNodeIndexPaths:self];
+  NSSet *visibleNodePathsSet = [NSSet setWithArray:visibleNodePaths];
   CGSize viewportSize = [_delegate rangeControllerViewportSize:self];
 
-  if ([_layoutController shouldUpdateForVisibleIndexPaths:indexPaths viewportSize:viewportSize range:ASLayoutRangeRender]) {
+  // the layout controller needs to know what the current visible indices are to calculate range offsets
-    [_layoutController setVisibleNodeIndexPaths:indexPaths];
+  [_layoutController setVisibleNodeIndexPaths:visibleNodePaths];
-    NSSet *workingRangeIndexPaths = [_layoutController indexPathsForScrolling:_scrollDirection viewportSize:viewportSize range:ASLayoutRangeRender];
-    NSSet *visibleRangeIndexPaths = [NSSet setWithArray:indexPaths];
 
-    NSMutableSet *removedIndexPaths = _workingRangeIsValid ? [_workingRangeIndexPaths mutableCopy] : [NSMutableSet set];
+  for (NSInteger i = 0; i < ASLayoutRangeTypeCount; i++) {
-    [removedIndexPaths minusSet:workingRangeIndexPaths];
+    ASLayoutRangeType rangeType = (ASLayoutRangeType)i;
-    [removedIndexPaths minusSet:visibleRangeIndexPaths];
+    id rangeKey = @(rangeType);
-    if (removedIndexPaths.count) {
+
-      NSArray *removedNodes = [_delegate rangeController:self nodesAtIndexPaths:[removedIndexPaths allObjects]];
+    // this delegate decide what happens when a node is added or removed from a range
-      [removedNodes enumerateObjectsUsingBlock:^(ASCellNode *node, NSUInteger idx, BOOL *stop) {
+    id<ASRangeDelegate> rangeDelegate = _rangeTypeDelegates[rangeKey];
-        [self removeNodeFromWorkingRange:node];
+
-      }];
+    if ([_layoutController shouldUpdateForVisibleIndexPaths:visibleNodePaths viewportSize:viewportSize rangeType:rangeType]) {
+      NSSet *indexPaths = [_layoutController indexPathsForScrolling:_scrollDirection viewportSize:viewportSize rangeType:rangeType];
+
+      // Notify to remove indexpaths that are leftover that are not visible or included in the _layoutController calculated paths
+      NSMutableSet *removedIndexPaths = _rangeIsValid ? [[_rangeTypeIndexPaths objectForKey:rangeKey] mutableCopy] : [NSMutableSet set];
+      [removedIndexPaths minusSet:indexPaths];
+      [removedIndexPaths minusSet:visibleNodePathsSet];
+      if (removedIndexPaths.count) {
+        NSArray *removedNodes = [_delegate rangeController:self nodesAtIndexPaths:[removedIndexPaths allObjects]];
+        [removedNodes enumerateObjectsUsingBlock:^(ASCellNode *node, NSUInteger idx, BOOL *stop) {
+          [rangeDelegate node:node exitedRangeType:rangeType];
+        }];
+      }
+
+      // Notify to add indexpaths that are not currently in _rangeTypeIndexPaths
+      NSMutableSet *addedIndexPaths = [indexPaths mutableCopy];
+      [addedIndexPaths minusSet:[_rangeTypeIndexPaths objectForKey:rangeKey]];
+
+      // The preload range (for example) should include nodes that are visible
+      if ([self shouldRemoveVisibleNodesFromRangeType:rangeType]) {
+        [addedIndexPaths minusSet:visibleNodePathsSet];
+      }
+
+      if (addedIndexPaths.count) {
+        NSArray *addedNodes = [_delegate rangeController:self nodesAtIndexPaths:[addedIndexPaths allObjects]];
+        [addedNodes enumerateObjectsUsingBlock:^(ASCellNode *node, NSUInteger idx, BOOL *stop) {
+          [rangeDelegate node:node enteredRangeType:rangeType];
+        }];
+      }
+
+      // set the range indexpaths so that we can remove/add on the next update pass
+      [_rangeTypeIndexPaths setObject:indexPaths forKey:rangeKey];
     }
-
-    NSMutableSet *addedIndexPaths = [workingRangeIndexPaths mutableCopy];
-    [addedIndexPaths minusSet:_workingRangeIndexPaths];
-    [addedIndexPaths minusSet:visibleRangeIndexPaths];
-    if (addedIndexPaths.count) {
-      NSArray *addedNodes = [_delegate rangeController:self nodesAtIndexPaths:[addedIndexPaths allObjects]];
-      [addedNodes enumerateObjectsUsingBlock:^(ASCellNode *node, NSUInteger idx, BOOL *stop) {
-        [self addNodeToWorkingRange:node];
-      }];
-    }
-
-    _workingRangeIndexPaths = workingRangeIndexPaths;
-    _workingRangeNodes = [NSSet setWithArray:[_delegate rangeController:self nodesAtIndexPaths:[workingRangeIndexPaths allObjects]]];
-    _workingRangeIsValid = YES;
   }
 
+  _rangeIsValid = YES;
   _queuedRangeUpdate = NO;
 }
 
+- (BOOL)shouldRemoveVisibleNodesFromRangeType:(ASLayoutRangeType)rangeType
+{
+  return rangeType != ASLayoutRangeTypePreload;
+}
+
 - (void)configureContentView:(UIView *)contentView forCellNode:(ASCellNode *)cellNode
 {
   [cellNode recursivelySetDisplaySuspended:NO];
@@ -204,21 +149,15 @@
     return;
   }
 
+  // clean the content view
   for (UIView *view in contentView.subviews) {
-    ASDisplayNode *node = view.asyncdisplaykit_node;
+    [view removeFromSuperview];
-    if (node) {
-      // plunk this node back into the working range, if appropriate
-      ASDisplayNodeAssert([node isKindOfClass:[ASCellNode class]], @"invalid node");
-      [self discardNode:(ASCellNode *)node];
-    } else {
-      // if it's not a node, it's something random UITableView added to the hierarchy.  kill it.
-      [view removeFromSuperview];
-    }
   }
 
   [self moveNode:cellNode toView:contentView];
 }
 
+
 #pragma mark - ASDataControllerDelegete
 
 - (void)dataControllerBeginUpdates:(ASDataController *)dataController {
@@ -252,7 +191,7 @@
   ASDisplayNodePerformBlockOnMainThread(^{
     [_layoutController insertNodesAtIndexPaths:indexPaths withSizes:nodeSizes];
     [_delegate rangeController:self didInsertNodesAtIndexPaths:indexPaths withAnimationOption:animationOption];
-    _workingRangeIsValid = NO;
+    _rangeIsValid = NO;
   });
 }
 
@@ -268,7 +207,7 @@
   ASDisplayNodePerformBlockOnMainThread(^{
     [_layoutController deleteNodesAtIndexPaths:indexPaths];
     [_delegate rangeController:self didDeleteNodesAtIndexPaths:indexPaths withAnimationOption:animationOption];
-    _workingRangeIsValid = NO;
+    _rangeIsValid = NO;
   });
 }
 
@@ -296,7 +235,7 @@
   ASDisplayNodePerformBlockOnMainThread(^{
     [_layoutController insertSections:sectionNodeSizes atIndexSet:indexSet];
     [_delegate rangeController:self didInsertSectionsAtIndexSet:indexSet withAnimationOption:animationOption];
-    _workingRangeIsValid = NO;
+    _rangeIsValid = NO;
   });
 }
 
@@ -312,7 +251,7 @@
   ASDisplayNodePerformBlockOnMainThread(^{
     [_layoutController deleteSectionsAtIndexSet:indexSet];
     [_delegate rangeController:self didDeleteSectionsAtIndexSet:indexSet withAnimationOption:animationOption];
-    _workingRangeIsValid = NO;
+    _rangeIsValid = NO;
   });
 }
 

AsyncDisplayKit/Details/ASRangeDelegate.h

@@ -0,0 +1,22 @@
+/* Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <Foundation/Foundation.h>
+
+#import <AsyncDisplayKit/ASLayoutRangeType.h>
+
+@class ASDisplayNode;
+
+@protocol ASRangeDelegate <NSObject>
+
+@required
+
+- (void)node:(ASDisplayNode *)node enteredRangeType:(ASLayoutRangeType)rangeType;
+- (void)node:(ASDisplayNode *)node exitedRangeType:(ASLayoutRangeType)rangeType;
+
+@end

AsyncDisplayKit/Details/ASRenderRangeDelegate.h

@@ -0,0 +1,15 @@
+/* Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <Foundation/Foundation.h>
+
+#import <AsyncDisplayKit/ASRangeDelegate.h>
+
+@interface ASRenderRangeDelegate : NSObject
+
+@end

AsyncDisplayKit/Details/ASRenderRangeDelegate.mm

@@ -0,0 +1,88 @@
+/* Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "ASRenderRangeDelegate.h"
+
+#import "ASDisplayNode.h"
+#import "ASDisplayNode+Subclasses.h"
+#import "ASDisplayNodeInternal.h"
+
+@interface ASDisplayNode (ASRenderRangeDelegate)
+
+- (void)display;
+- (void)recursivelyDisplay;
+
+@end
+
+@implementation ASDisplayNode (ASRenderRangeDelegate)
+
+- (void)display
+{
+  if (![self __shouldLoadViewOrLayer]) {
+    return;
+  }
+
+  ASDisplayNodeAssertMainThread();
+  ASDisplayNodeAssert(self.nodeLoaded, @"backing store must be loaded before calling -display");
+
+  CALayer *layer = self.layer;
+
+  // rendering a backing store requires a node be laid out
+  [layer setNeedsLayout];
+  [layer layoutIfNeeded];
+
+  if (layer.contents) {
+    return;
+  }
+
+  [layer setNeedsDisplay];
+  [layer displayIfNeeded];
+}
+
+- (void)recursivelyDisplay
+{
+  if (![self __shouldLoadViewOrLayer]) {
+    return;
+  }
+
+  for (ASDisplayNode *node in self.subnodes) {
+    [node recursivelyDisplay];
+  }
+
+  [self display];
+}
+
+@end
+
+@implementation ASRenderRangeDelegate
+
+- (void)node:(ASDisplayNode *)node enteredRangeType:(ASLayoutRangeType)rangeType
+{
+  ASDisplayNodeAssertMainThread();
+  ASDisplayNodeAssert(node, @"invalid argument");
+
+  // if node is in the working range it should not actively be in view
+  [node.view removeFromSuperview];
+
+  [node recursivelyDisplay];
+}
+
+- (void)node:(ASDisplayNode *)node exitedRangeType:(ASLayoutRangeType)rangeType
+{
+  ASDisplayNodeAssertMainThread();
+  ASDisplayNodeAssert(node, @"invalid argument");
+
+  [node recursivelySetDisplaySuspended:YES];
+  [node.view removeFromSuperview];
+
+  // since this class usually manages large or infinite data sets, the working range
+  // directly bounds memory usage by requiring redrawing any content that falls outside the range.
+  [node recursivelyClearRendering];
+}
+
+@end

examples/Kittens/Sample/ViewController.m

@@ -17,7 +17,7 @@
 #import "BlurbNode.h"
 #import "KittenNode.h"
 
-static const NSInteger kLitterSize = 20;
+static const NSInteger kLitterSize = 200;
 
 
 @interface ViewController () <ASTableViewDataSource, ASTableViewDelegate>