Make ASWeakSet and NSArray+Diffing public, add support for large arrays (#2078)

AsyncDisplayKit/Details/ASWeakSet.h

@@ -0,0 +1,46 @@
+//
+//  ASWeakSet.h
+//  AsyncDisplayKit
+//
+//  Created by Adlai Holler on 1/7/16.
+//
+//  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>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface ASWeakSet<__covariant ObjectType> : NSObject<NSFastEnumeration>
+
+/// Returns YES if the receiver is empty, NO otherwise.
+@property (nonatomic, readonly, getter=isEmpty) BOOL empty;
+
+/// Returns YES if `object` is in the receiver, NO otherwise.
+- (BOOL)containsObject:(ObjectType)object;
+
+/// Insets `object` into the set.
+- (void)addObject:(ObjectType)object;
+
+/// Removes object from the set.
+- (void)removeObject:(ObjectType)object;
+
+/// Removes all objects from the set.
+- (void)removeAllObjects;
+
+/// Returns a standard *retained* NSArray of all objects.  Not free to generate, but useful for iterating over contents.
+- (NSArray *)allObjects;
+
+/**
+ * How many objects are contained in this set.
+ 
+ * NOTE: This computed property is O(N). Consider using the `empty` property.
+ */
+@property (nonatomic, readonly) NSUInteger count;
+
+@end
+
+NS_ASSUME_NONNULL_END