From e852cb612c0b1d5b26818fae0b3f2e7f83b7ff85 Mon Sep 17 00:00:00 2001
From: Levi McCallum <levi@pinterest.com>
Date: Sun, 31 Jan 2016 21:17:24 -0800
Subject: [PATCH] Simplify usage of diffing API

---
 AsyncDisplayKit/ASDisplayNode.mm          |  1 +
 AsyncDisplayKit/Private/NSArray+Diffing.h |  2 +-
 AsyncDisplayKit/Private/NSArray+Diffing.m | 10 +++++++---
 AsyncDisplayKitTests/ArrayDiffingTests.m  |  3 +--
 4 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/AsyncDisplayKit/ASDisplayNode.mm b/AsyncDisplayKit/ASDisplayNode.mm
index 032e2fecd4..bfd4cd3584 100644
--- a/AsyncDisplayKit/ASDisplayNode.mm
+++ b/AsyncDisplayKit/ASDisplayNode.mm
@@ -21,6 +21,7 @@
 #import "_ASCoreAnimationExtras.h"
 #import "ASDisplayNodeExtras.h"
 #import "ASEqualityHelpers.h"
+#import "NSArray+Diffing.h"
 
 #import "ASInternalHelpers.h"
 #import "ASLayout.h"
diff --git a/AsyncDisplayKit/Private/NSArray+Diffing.h b/AsyncDisplayKit/Private/NSArray+Diffing.h
index 618e1901ea..374096f92f 100644
--- a/AsyncDisplayKit/Private/NSArray+Diffing.h
+++ b/AsyncDisplayKit/Private/NSArray+Diffing.h
@@ -13,6 +13,6 @@
 /**
  * Uses a bottom-up memoized longest common subsequence solution to identify differences. Runs in O(mn) complexity.
  */
-- (void)asdk_diffWithArray:(NSArray *)array insertions:(NSMutableIndexSet **)insertions deletions:(NSMutableIndexSet **)deletions;
+- (void)asdk_diffWithArray:(NSArray *)array insertions:(NSIndexSet **)insertions deletions:(NSIndexSet **)deletions;
 
 @end
diff --git a/AsyncDisplayKit/Private/NSArray+Diffing.m b/AsyncDisplayKit/Private/NSArray+Diffing.m
index f320bcfb58..0cd9ad040b 100644
--- a/AsyncDisplayKit/Private/NSArray+Diffing.m
+++ b/AsyncDisplayKit/Private/NSArray+Diffing.m
@@ -10,28 +10,32 @@
 
 @implementation NSArray (Diffing)
 
-- (void)asdk_diffWithArray:(NSArray *)array insertions:(NSMutableIndexSet **)insertions deletions:(NSMutableIndexSet **)deletions
+- (void)asdk_diffWithArray:(NSArray *)array insertions:(NSIndexSet **)insertions deletions:(NSIndexSet **)deletions
 {
   NSIndexSet *commonIndexes = [self _asdk_commonIndexesWithArray:array];
   
   if (insertions) {
     NSArray *commonObjects = [self objectsAtIndexes:commonIndexes];
+    NSMutableIndexSet *insertionIndexes = [NSMutableIndexSet indexSet];
     for (NSInteger i = 0, j = 0; i < commonObjects.count || j < array.count;) {
       if (i < commonObjects.count && j < array.count && [commonObjects[i] isEqual:array[j]]) {
         i++; j++;
       } else {
-        [*insertions addIndex:j];
+        [insertionIndexes addIndex:j];
         j++;
       }
     }
+    *insertions = insertionIndexes;
   }
   
   if (deletions) {
+    NSMutableIndexSet *deletionIndexes = [NSMutableIndexSet indexSet];
     for (NSInteger i = 0; i < self.count; i++) {
       if (![commonIndexes containsIndex:i]) {
-        [*deletions addIndex:i];
+        [deletionIndexes addIndex:i];
       }
     }
+    *deletions = deletionIndexes;
   }
 }
 
diff --git a/AsyncDisplayKitTests/ArrayDiffingTests.m b/AsyncDisplayKitTests/ArrayDiffingTests.m
index c83e841051..d2224e0baa 100644
--- a/AsyncDisplayKitTests/ArrayDiffingTests.m
+++ b/AsyncDisplayKitTests/ArrayDiffingTests.m
@@ -57,8 +57,7 @@
   ];
   
   for (NSArray *test in tests) {
-    NSMutableIndexSet *insertions = [NSMutableIndexSet indexSet];
-    NSMutableIndexSet *deletions = [NSMutableIndexSet indexSet];
+    NSIndexSet *insertions, *deletions;
     [test[0] asdk_diffWithArray:test[1] insertions:&insertions deletions:&deletions];
     for (NSNumber *index in (NSArray *)test[2]) {
       XCTAssert([insertions containsIndex:[index integerValue]]);