swift api compatibility

YYAsyncLayer/YYAsyncLayer.h

@@ -22,9 +22,9 @@ FOUNDATION_EXPORT const unsigned char YYAsyncLayerVersionString[];
 #import "YYTransaction.h"
 #endif
 
-
 @class YYAsyncLayerDisplayTask;
 
+NS_ASSUME_NONNULL_BEGIN
 
 /**
  The YYAsyncLayer class is a subclass of CALayer used for render contents asynchronously.
@@ -60,7 +60,7 @@ FOUNDATION_EXPORT const unsigned char YYAsyncLayerVersionString[];
  
  @param layer  The layer.
  */
-@property (nonatomic, copy) void (^willDisplay)(CALayer *layer);
+@property (nullable, nonatomic, copy) void (^willDisplay)(CALayer *layer);
 
 /**
  This block is called to draw the layer's contents.
@@ -73,7 +73,7 @@ FOUNDATION_EXPORT const unsigned char YYAsyncLayerVersionString[];
  @param isCancelled  If this block returns `YES`, the method should cancel the
  drawing process and return as quickly as possible.
  */
-@property (nonatomic, copy) void (^display)(CGContextRef context, CGSize size, BOOL(^isCancelled)(void));
+@property (nullable, nonatomic, copy) void (^display)(CGContextRef context, CGSize size, BOOL(^isCancelled)(void));
 
 /**
  This block will be called after the asynchronous drawing finished.
@@ -82,6 +82,8 @@ FOUNDATION_EXPORT const unsigned char YYAsyncLayerVersionString[];
  @param layer  The layer.
  @param finished  If the draw process is cancelled, it's `NO`, otherwise it's `YES`;
  */
-@property (nonatomic, copy) void (^didDisplay)(CALayer *layer, BOOL finished);
+@property (nullable, nonatomic, copy) void (^didDisplay)(CALayer *layer, BOOL finished);
 
 @end
+
+NS_ASSUME_NONNULL_END

YYAsyncLayer/YYSentinel.h

@@ -11,17 +11,21 @@
 
 #import <Foundation/Foundation.h>
 
+NS_ASSUME_NONNULL_BEGIN
+
 /**
  YYSentinel is a thread safe incrementing counter. 
  It may be used in some multi-threaded situation.
  */
 @interface YYSentinel : NSObject
 
 /// Returns the current value of the counter.
-@property (atomic, readonly) int32_t value;
+@property (readonly) int32_t value;
 
 /// Increase the value atomically.
 /// @return The new value.
 - (int32_t)increase;
 
 @end
+
+NS_ASSUME_NONNULL_END

YYAsyncLayer/YYTransaction.h

@@ -11,6 +11,8 @@
 
 #import <Foundation/Foundation.h>
 
+NS_ASSUME_NONNULL_BEGIN
+
 /**
  YYTransaction let you perform a selector once before current runloop sleep.
  */
@@ -36,3 +38,5 @@
 - (void)commit;
 
 @end
+
+NS_ASSUME_NONNULL_END