From e1ea2d2151d2ef6506a328dcd2fecceedecddecf Mon Sep 17 00:00:00 2001
From: Levi McCallum <levi.mccallum@nfl.com>
Date: Tue, 6 Oct 2015 12:02:28 -0700
Subject: [PATCH] Handle supplementary node generation during insertion of new
 section

---
 .../Details/ASCollectionDataController.mm     | 20 +++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/AsyncDisplayKit/Details/ASCollectionDataController.mm b/AsyncDisplayKit/Details/ASCollectionDataController.mm
index 17e5b00c98..98d4fb4895 100644
--- a/AsyncDisplayKit/Details/ASCollectionDataController.mm
+++ b/AsyncDisplayKit/Details/ASCollectionDataController.mm
@@ -78,12 +78,28 @@
 
 - (void)prepareInsertSections:(NSIndexSet *)sections
 {
-  // TODO: Implement
+  NSArray *elementKinds = [self.collectionDataSource supplementaryNodeKindsInDataController:self];
+  [elementKinds enumerateObjectsUsingBlock:^(NSString *kind, NSUInteger idx, BOOL *stop) {
+    LOG(@"Populating elements of kind: %@, for sections: %@", kind, sections);
+    NSMutableArray *nodes = [NSMutableArray array];
+    NSMutableArray *indexPaths = [NSMutableArray array];
+    [self _populateSupplementaryNodesOfKind:kind withSections:sections mutableNodes:nodes mutableIndexPaths:indexPaths];
+    _pendingNodes[kind] = nodes;
+    _pendingIndexPaths[kind] = indexPaths;
+  }];
 }
 
 - (void)willInsertSections:(NSIndexSet *)sections
 {
-  // TODO: Implement
+  [_pendingNodes enumerateKeysAndObjectsUsingBlock:^(NSString *kind, NSMutableArray *nodes, BOOL *stop) {
+    NSMutableArray *sectionArray = [NSMutableArray arrayWithCapacity:sections.count];
+    for (NSUInteger i = 0; i < sections.count; i++) {
+      [sectionArray addObject:[NSMutableArray array]];
+    }
+    
+    [self insertSections:sectionArray ofKind:kind atIndexSet:sections completion:nil];
+    [self batchLayoutNodes:nodes ofKind:kind atIndexPaths:_pendingIndexPaths[kind] completion:nil];
+  }];
 }
 
 - (void)willDeleteSections:(NSIndexSet *)sections