Merge pull request #51 from SDWebImage/feature_replace_semaphore_with_os_unfair_lock_and_spinlock

Replace the dispatch semaphore into os_unfair_lock, copied from SDWebImage Core

Author: dreampiggy

SDWebImageWebPCoder/Classes/SDImageWebPCoder.m

@@ -7,6 +7,10 @@
  */
 
 #import "SDImageWebPCoder.h"
+#import "SDWebImageWebPCoderDefine.h"
+#import <Accelerate/Accelerate.h>
+#import <os/lock.h>
+#import <libkern/OSAtomic.h>
 
 #if __has_include("webp/decode.h") && __has_include("webp/encode.h") && __has_include("webp/demux.h") && __has_include("webp/mux.h")
 #import "webp/decode.h"
@@ -22,8 +26,47 @@
 @import libwebp;
 #endif
 
-#import <Accelerate/Accelerate.h>
-#import "SDWebImageWebPCoderDefine.h"
+#define SD_USE_OS_UNFAIR_LOCK TARGET_OS_MACCATALYST ||\
+    (__IPHONE_OS_VERSION_MIN_REQUIRED >= __IPHONE_10_0) ||\
+    (__MAC_OS_X_VERSION_MIN_REQUIRED >= __MAC_10_12) ||\
+    (__TV_OS_VERSION_MIN_REQUIRED >= __TVOS_10_0) ||\
+    (__WATCH_OS_VERSION_MIN_REQUIRED >= __WATCHOS_3_0)
+
+#ifndef SD_LOCK_DECLARE
+#if SD_USE_OS_UNFAIR_LOCK
+#define SD_LOCK_DECLARE(lock) os_unfair_lock lock
+#else
+#define SD_LOCK_DECLARE(lock) os_unfair_lock lock API_AVAILABLE(ios(10.0), tvos(10), watchos(3), macos(10.12)); \
+OSSpinLock lock##_deprecated;
+#endif
+#endif
+
+#ifndef SD_LOCK_INIT
+#if SD_USE_OS_UNFAIR_LOCK
+#define SD_LOCK_INIT(lock) lock = OS_UNFAIR_LOCK_INIT
+#else
+#define SD_LOCK_INIT(lock) if (@available(iOS 10, tvOS 10, watchOS 3, macOS 10.12, *)) lock = OS_UNFAIR_LOCK_INIT; \
+else lock##_deprecated = OS_SPINLOCK_INIT;
+#endif
+#endif
+
+#ifndef SD_LOCK
+#if SD_USE_OS_UNFAIR_LOCK
+#define SD_LOCK(lock) os_unfair_lock_lock(&lock)
+#else
+#define SD_LOCK(lock) if (@available(iOS 10, tvOS 10, watchOS 3, macOS 10.12, *)) os_unfair_lock_lock(&lock); \
+else OSSpinLockLock(&lock##_deprecated);
+#endif
+#endif
+
+#ifndef SD_UNLOCK
+#if SD_USE_OS_UNFAIR_LOCK
+#define SD_UNLOCK(lock) os_unfair_lock_unlock(&lock)
+#else
+#define SD_UNLOCK(lock) if (@available(iOS 10, tvOS 10, watchOS 3, macOS 10.12, *)) os_unfair_lock_unlock(&lock); \
+else OSSpinLockUnlock(&lock##_deprecated);
+#endif
+#endif
 
 /// Calculate the actual thumnail pixel size
 static CGSize SDCalculateThumbnailSize(CGSize fullSize, BOOL preserveAspectRatio, CGSize thumbnailSize) {
@@ -99,7 +142,7 @@ @implementation SDImageWebPCoder {
     BOOL _finished;
     CGFloat _canvasWidth;
     CGFloat _canvasHeight;
-    dispatch_semaphore_t _lock;
+    SD_LOCK_DECLARE(_lock);
     NSUInteger _currentBlendIndex;
     BOOL _preserveAspectRatio;
     CGSize _thumbnailSize;
@@ -292,7 +335,7 @@ - (instancetype)initIncrementalWithOptions:(nullable SDImageCoderOptions *)optio
         }
         _preserveAspectRatio = preserveAspectRatio;
         _currentBlendIndex = NSNotFound;
-        _lock = dispatch_semaphore_create(1);
+        SD_LOCK_INIT(_lock);
     }
     return self;
 }
@@ -975,7 +1018,7 @@ - (instancetype)initWithAnimatedImageData:(NSData *)data options:(nullable SDIma
         _demux = demuxer;
         _imageData = data;
         _currentBlendIndex = NSNotFound;
-        _lock = dispatch_semaphore_create(1);
+        SD_LOCK_INIT(_lock);
     }
     return self;
 }