[Umbrella] ASCollectionView -> ASCollectionNode Migration, Separate Index Spaces (#2372)

* Separate dataSource & UIKit index spaces

Beef up our supplementary node support

Make the API way better

Go nuts

Add a unit test for UICollectionView's handling of reloadData inside batch updates

Wrap indexPathForNode: in a cache

Convert index paths in delegate methods

Go back on table view

Put collection view back

Switch up the API

Move most ASCollectionView API to ASCollectionNode

Move most table logic over to ASTableNode

Do the things

More conversion work

Keep on keepin' on

Get table view delegate API done

More porting

Simplify

Clear the delegate

More cleanup

Move more stuff around

Remove pointless file

Re-add some API

Put back more API

Use the right flag

* Some cleanup

* Remove incorrect comment

* Tweak the API

* Put back a couple methods

* update example projects (note: ASCollectionView deprecation warnings expected)

* change reloadDataWithCompletion:nil --> reloadData

* Clean up rebase

* Make deprecated numberOfItemsInSection methods optional

* Use the right flag

* Address nits

* update ASDKTube, ASDKgram & ASViewController examples

AsyncDisplayKitTests/ASCollectionViewTests.mm

@@ -18,6 +18,7 @@
 #import "ASSectionContext.h"
 #import <vector>
 #import <OCMock/OCMock.h>
+#import "ASCollectionView+Undeprecated.h"
 
 @interface ASTextCellNodeWithSetSelectedCounter : ASTextCellNode
 
@@ -54,7 +55,7 @@
 
 @end
 
-@interface ASCollectionViewTestDelegate : NSObject <ASCollectionViewDataSource, ASCollectionViewDelegate>
+@interface ASCollectionViewTestDelegate : NSObject <ASCollectionDataSource, ASCollectionDelegate, UICollectionViewDelegateFlowLayout>
 
 @property (nonatomic, assign) NSInteger sectionGeneration;
 
@@ -110,7 +111,7 @@
   return _itemCounts[section];
 }
 
-- (id<ASSectionContext>)collectionView:(ASCollectionView *)collectionView contextForSection:(NSInteger)section
+- (id<ASSectionContext>)collectionNode:(ASCollectionNode *)collectionNode contextForSection:(NSInteger)section
 {
   ASTestSectionContext *context = [[ASTestSectionContext alloc] init];
   context.sectionGeneration = _sectionGeneration;
@@ -118,12 +119,23 @@
   return context;
 }
 
+- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section
+{
+  return CGSizeMake(100, 100);
+}
+
+- (ASCellNode *)collectionView:(ASCollectionView *)collectionView nodeForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
+{
+  return [[ASCellNode alloc] init];
+}
+
 @end
 
 @interface ASCollectionViewTestController: UIViewController
 
 @property (nonatomic, strong) ASCollectionViewTestDelegate *asyncDelegate;
 @property (nonatomic, strong) ASCollectionView *collectionView;
+@property (nonatomic, strong) ASCollectionNode *collectionNode;
 
 @end
 
@@ -136,12 +148,13 @@
     self.asyncDelegate = [[ASCollectionViewTestDelegate alloc] initWithNumberOfSections:10 numberOfItemsInSection:10];
     id realLayout = [UICollectionViewFlowLayout new];
     id mockLayout = [OCMockObject partialMockForObject:realLayout];
-    self.collectionView = [[ASCollectionView alloc] initWithFrame:self.view.bounds
-                                             collectionViewLayout:mockLayout];
+    self.collectionNode = [[ASCollectionNode alloc] initWithFrame:self.view.bounds collectionViewLayout:mockLayout];
+    self.collectionView = self.collectionNode.view;
     self.collectionView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
-    self.collectionView.asyncDataSource = self.asyncDelegate;
-    self.collectionView.asyncDelegate = self.asyncDelegate;
+    self.collectionNode.dataSource = self.asyncDelegate;
+    self.collectionNode.delegate = self.asyncDelegate;
     
+    [self.collectionNode registerSupplementaryNodeOfKind:UICollectionElementKindSectionHeader];
     [self.view addSubview:self.collectionView];
   }
   return self;
@@ -303,6 +316,7 @@
   ASCollectionViewTestController *testController = [[ASCollectionViewTestController alloc] initWithNibName:nil bundle:nil];\
   __unused ASCollectionViewTestDelegate *del = testController.asyncDelegate;\
   __unused ASCollectionView *cv = testController.collectionView;\
+  __unused ASCollectionNode *cn = testController.collectionNode;\
   UIWindow *window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];\
   [window makeKeyAndVisible]; \
   window.rootViewController = testController;\
@@ -404,7 +418,7 @@
 - (void)testCellNodeLayoutAttributes
 {
   updateValidationTestPrologue
-  NSSet *nodeBatch1 = [NSSet setWithArray:[cv visibleNodes]];
+  NSSet *nodeBatch1 = [NSSet setWithArray:[cn visibleNodes]];
   XCTAssertGreaterThan(nodeBatch1.count, 0);
 
   // Expect all visible nodes get 1 applyLayoutAttributes and have a non-nil value.
@@ -419,7 +433,7 @@
   [cv layoutIfNeeded];
 
   // Ensure we scrolled far enough that all the old ones are offscreen.
-  NSSet *nodeBatch2 = [NSSet setWithArray:[cv visibleNodes]];
+  NSSet *nodeBatch2 = [NSSet setWithArray:[cn visibleNodes]];
   XCTAssertFalse([nodeBatch1 intersectsSet:nodeBatch2], @"Expected to scroll far away enough that all nodes are replaced.");
 
   // Now the nodes are no longer visible, expect their layout attributes are nil but not another applyLayoutAttributes call.
@@ -438,7 +452,8 @@
 {
   UIWindow *window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
   UICollectionViewLayout *layout = [[UICollectionViewFlowLayout alloc] init];
-  ASCollectionView *cv = [[ASCollectionView alloc] initWithFrame:window.bounds collectionViewLayout:layout];
+  ASCollectionNode *cn = [[ASCollectionNode alloc] initWithFrame:window.bounds collectionViewLayout:layout];
+  ASCollectionView *cv = cn.view;
 
 
   __unused NSMutableSet *keepaliveNodes = [NSMutableSet set];
@@ -455,7 +470,7 @@
     layerBacked.name = [NSString stringWithFormat:@"Subnode #%d", thisNodeIdx];
     [suppNode addSubnode:layerBacked];
     [invocation setReturnValue:&suppNode];
-  }] collectionView:cv nodeForSupplementaryElementOfKind:UICollectionElementKindSectionHeader atIndexPath:OCMOCK_ANY];
+  }] collectionNode:cn nodeForSupplementaryElementOfKind:UICollectionElementKindSectionHeader atIndexPath:OCMOCK_ANY];
   [[[dataSource stub] andReturnValue:[NSNumber numberWithInteger:1]] numberOfSectionsInCollectionView:cv];
   cv.asyncDataSource = dataSource;
 
@@ -483,14 +498,14 @@
 {
   updateValidationTestPrologue
   id layout = cv.collectionViewLayout;
-  CGSize initialItemSize = [cv calculatedSizeForNodeAtIndexPath:[NSIndexPath indexPathForItem:0 inSection:0]];
+  CGSize initialItemSize = [cv nodeForItemAtIndexPath:[NSIndexPath indexPathForItem:0 inSection:0]].calculatedSize;
   CGSize initialCVSize = cv.bounds.size;
 
   // Capture the node size before first call to prepareLayout after frame change.
   __block CGSize itemSizeAtFirstLayout = CGSizeZero;
   __block CGSize boundsSizeAtFirstLayout = CGSizeZero;
   [[[[layout expect] andDo:^(NSInvocation *) {
-    itemSizeAtFirstLayout = [cv calculatedSizeForNodeAtIndexPath:[NSIndexPath indexPathForItem:0 inSection:0]];
+    itemSizeAtFirstLayout = [cv nodeForItemAtIndexPath:[NSIndexPath indexPathForItem:0 inSection:0]].calculatedSize;
     boundsSizeAtFirstLayout = [cv bounds].size;
   }] andForwardToRealObject] prepareLayout];
 
@@ -498,7 +513,7 @@
   UIDeviceOrientation oldDeviceOrientation = [[UIDevice currentDevice] orientation];
   [[UIDevice currentDevice] setValue:@(UIDeviceOrientationLandscapeLeft) forKey:@"orientation"];
 
-  CGSize finalItemSize = [cv calculatedSizeForNodeAtIndexPath:[NSIndexPath indexPathForItem:0 inSection:0]];
+  CGSize finalItemSize = [cv nodeForItemAtIndexPath:[NSIndexPath indexPathForItem:0 inSection:0]].calculatedSize;
   CGSize finalCVSize = cv.bounds.size;
   XCTAssertNotEqualObjects(NSStringFromCGSize(initialItemSize),  NSStringFromCGSize(itemSizeAtFirstLayout));
   XCTAssertNotEqualObjects(NSStringFromCGSize(initialCVSize),  NSStringFromCGSize(boundsSizeAtFirstLayout));
@@ -562,7 +577,7 @@
   updateValidationTestPrologue
   NSInteger sectionCount = del->_itemCounts.size();
   for (NSInteger section = 0; section < sectionCount; section++) {
-    ASTestSectionContext *context = (ASTestSectionContext *)[cv contextForSection:section];
+    ASTestSectionContext *context = (ASTestSectionContext *)[cn contextForSection:section];
     XCTAssertNotNil(context);
     XCTAssertEqual(context.sectionGeneration, 1);
     XCTAssertEqual(context.sectionIndex, section);
@@ -582,7 +597,7 @@
   
   // Only test left moving
   XCTAssertTrue(toSection < originalSection);
-  ASTestSectionContext *movedSectionContext = (ASTestSectionContext *)[cv contextForSection:toSection];
+  ASTestSectionContext *movedSectionContext = (ASTestSectionContext *)[cn contextForSection:toSection];
   XCTAssertNotNil(movedSectionContext);
   // ASCollectionView currently uses ASChangeSetDataController which splits a move operation to a pair of delete and insert ones.
   // So this movedSectionContext is newly loaded and thus is second generation.
@@ -590,7 +605,7 @@
   XCTAssertEqual(movedSectionContext.sectionIndex, toSection);
   
   for (NSInteger section = toSection + 1; section <= originalSection && section < sectionCount; section++) {
-    ASTestSectionContext *context = (ASTestSectionContext *)[cv contextForSection:section];
+    ASTestSectionContext *context = (ASTestSectionContext *)[cn contextForSection:section];
     XCTAssertNotNil(context);
     XCTAssertEqual(context.sectionGeneration, 1);
     // This section context was shifted to the right
@@ -607,7 +622,7 @@
   
   NSInteger sectionCount = del->_itemCounts.size();
   for (NSInteger section = 0; section < sectionCount; section++) {
-    ASTestSectionContext *context = (ASTestSectionContext *)[cv contextForSection:section];
+    ASTestSectionContext *context = (ASTestSectionContext *)[cn contextForSection:section];
     XCTAssertNotNil(context);
     XCTAssertEqual(context.sectionGeneration, 2);
     XCTAssertEqual(context.sectionIndex, section);
@@ -625,7 +640,7 @@
   
   NSInteger sectionCount = del->_itemCounts.size();
   for (NSInteger section = 0; section < sectionCount; section++) {
-    ASTestSectionContext *context = (ASTestSectionContext *)[cv contextForSection:section];
+    ASTestSectionContext *context = (ASTestSectionContext *)[cn contextForSection:section];
     XCTAssertNotNil(context);
     XCTAssertEqual(context.sectionGeneration, section != sectionToReload ? 1 : 2);
     XCTAssertEqual(context.sectionIndex, section);
@@ -648,4 +663,39 @@
   XCTAssertNoThrow([cv insertSections:[NSIndexSet indexSetWithIndex:0]]);
 }
 
+- (void)testThatNodeAtIndexPathIsCorrectImmediatelyAfterSubmittingUpdate
+{
+  updateValidationTestPrologue
+  NSIndexPath *indexPath = [NSIndexPath indexPathForItem:0 inSection:0];
+
+  // Insert an item and assert nodeForItemAtIndexPath: immediately returns new node
+  ASCellNode *oldNode = [cn nodeForItemAtIndexPath:indexPath];
+  XCTAssertNotNil(oldNode);
+  del->_itemCounts[0] += 1;
+  [cv insertItemsAtIndexPaths:@[ indexPath ]];
+  ASCellNode *newNode = [cn nodeForItemAtIndexPath:indexPath];
+  XCTAssertNotNil(newNode);
+  XCTAssertNotEqualObjects(oldNode, newNode);
+
+  // Delete all sections and assert nodeForItemAtIndexPath: immediately returns nil
+  NSIndexSet *sections = [NSIndexSet indexSetWithIndexesInRange:NSMakeRange(0, del->_itemCounts.size())];
+  del->_itemCounts.clear();
+  [cv deleteSections:sections];
+  XCTAssertNil([cn nodeForItemAtIndexPath:indexPath]);
+}
+
+- (void)DISABLED_testThatSupplementaryNodeAtIndexPathIsCorrectImmediatelyAfterSubmittingUpdate
+{
+  updateValidationTestPrologue
+  NSIndexPath *indexPath = [NSIndexPath indexPathForItem:0 inSection:0];
+  ASCellNode *oldHeader = [cv supplementaryNodeForElementKind:UICollectionElementKindSectionHeader atIndexPath:indexPath];
+  XCTAssertNotNil(oldHeader);
+
+  // Reload the section and ensure that the new header is loaded
+  [cv reloadSections:[NSIndexSet indexSetWithIndex:0]];
+  ASCellNode *newHeader = [cv supplementaryNodeForElementKind:UICollectionElementKindSectionHeader atIndexPath:indexPath];
+  XCTAssertNotNil(newHeader);
+  XCTAssertNotEqualObjects(oldHeader, newHeader);
+}
+
 @end