Merge pull request #3429 from dreampiggy/perf/remove_conforms_to_protocol

Replace conformsToProtocol call with appropriate respondsToSelector check to improve performance

SDWebImage/Core/SDAnimatedImageView.m

@@ -471,7 +471,7 @@
 {
     if ([image.class conformsToProtocol:@protocol(SDAnimatedImage)] && image.sd_isIncremental && [image respondsToSelector:@selector(animatedCoder)]) {
         id<SDAnimatedImageCoder> animatedCoder = [(id<SDAnimatedImage>)image animatedCoder];
-        if ([animatedCoder conformsToProtocol:@protocol(SDProgressiveImageCoder)]) {
+        if ([animatedCoder respondsToSelector:@selector(initIncrementalWithOptions:)]) {
             return (id<SDAnimatedImageCoder, SDProgressiveImageCoder>)animatedCoder;
         }
     }

SDWebImage/Core/SDImageCache.m

@@ -245,7 +245,7 @@ static NSString * _defaultDiskCacheDirectory;
     dispatch_async(self.ioQueue, ^{
         @autoreleasepool {
             NSData *data = imageData;
-            if (!data && [image conformsToProtocol:@protocol(SDAnimatedImage)]) {
+            if (!data && [image respondsToSelector:@selector(animatedImageData)]) {
                 // If image is custom animated image class, prefer its original animated data
                 data = [((id<SDAnimatedImage>)image) animatedImageData];
             }
@@ -440,8 +440,7 @@ static NSString * _defaultDiskCacheDirectory;
     if (image) {
         if (options & SDImageCacheDecodeFirstFrameOnly) {
             // Ensure static image
-            Class animatedImageClass = image.class;
+            if (image.sd_isAnimated) {
-            if (image.sd_isAnimated || ([animatedImageClass isSubclassOfClass:[UIImage class]] && [animatedImageClass conformsToProtocol:@protocol(SDAnimatedImage)])) {
 #if SD_MAC
                 image = [[NSImage alloc] initWithCGImage:image.CGImage scale:image.scale orientation:kCGImagePropertyOrientationUp];
 #else
@@ -574,8 +573,7 @@ static NSString * _defaultDiskCacheDirectory;
     if (image) {
         if (options & SDImageCacheDecodeFirstFrameOnly) {
             // Ensure static image
-            Class animatedImageClass = image.class;
+            if (image.sd_isAnimated) {
-            if (image.sd_isAnimated || ([animatedImageClass isSubclassOfClass:[UIImage class]] && [animatedImageClass conformsToProtocol:@protocol(SDAnimatedImage)])) {
 #if SD_MAC
                 image = [[NSImage alloc] initWithCGImage:image.CGImage scale:image.scale orientation:kCGImagePropertyOrientationUp];
 #else

SDWebImage/Core/SDImageCacheDefine.m

@@ -94,10 +94,8 @@ UIImage * _Nullable SDImageCacheDecodeImageData(NSData * _Nonnull imageData, NSS
     CGFloat scale = [coderOptions[SDImageCoderDecodeScaleFactor] doubleValue];
     
     // Grab the image coder
-    id<SDImageCoder> imageCoder;
+    id<SDImageCoder> imageCoder = context[SDWebImageContextImageCoder];
-    if ([context[SDWebImageContextImageCoder] conformsToProtocol:@protocol(SDImageCoder)]) {
+    if (!imageCoder) {
-        imageCoder = context[SDWebImageContextImageCoder];
-    } else {
         imageCoder = [SDImageCodersManager sharedManager];
     }
     
@@ -128,12 +126,6 @@ UIImage * _Nullable SDImageCacheDecodeImageData(NSData * _Nonnull imageData, NSS
         if (lazyDecode) {
             // lazyDecode = NO means we should not forceDecode, highest priority
             shouldDecode = NO;
-        } else if ([image.class conformsToProtocol:@protocol(SDAnimatedImage)]) {
-            // `SDAnimatedImage` do not decode
-            shouldDecode = NO;
-        } else if (image.sd_isAnimated) {
-            // animated image do not decode
-            shouldDecode = NO;
         }
         if (shouldDecode) {
             image = [SDImageCoderHelper decodedImageWithImage:image];

SDWebImage/Core/SDImageIOAnimatedCoder.m

@@ -23,8 +23,8 @@ static NSString * kSDCGImageSourceRasterizationDPI = @"kCGImageSourceRasterizati
 // Specify File Size for lossy format encoding, like JPEG
 static NSString * kSDCGImageDestinationRequestedFileSize = @"kCGImageDestinationRequestedFileSize";
 
-// Only assert on Debug mode and Simulator
+// Only assert on Debug mode
-#define SD_CHECK_CGIMAGE_RETAIN_SOURCE DEBUG && TARGET_OS_SIMULATOR && \
+#define SD_CHECK_CGIMAGE_RETAIN_SOURCE DEBUG && \
     ((__IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_15_0)) || \
     ((__TV_OS_VERSION_MAX_ALLOWED >= __TVOS_15_0))
 
@@ -300,10 +300,12 @@ static CGImageRef __nullable SDCGImageCreateCopy(CGImageRef cg_nullable image) {
         }
     }
 #if SD_CHECK_CGIMAGE_RETAIN_SOURCE
-    // Assert here to check CGImageRef should not retain the CGImageSourceRef and has possible thread-safe issue (this is behavior on iOS 15+)
+    if (@available(iOS 15, tvOS 15, *)) {
-    // If assert hit, fire issue to https://github.com/SDWebImage/SDWebImage/issues and we update the condition for this behavior check
+        // Assert here to check CGImageRef should not retain the CGImageSourceRef and has possible thread-safe issue (this is behavior on iOS 15+)
-    extern CGImageSourceRef CGImageGetImageSource(CGImageRef);
+        // If assert hit, fire issue to https://github.com/SDWebImage/SDWebImage/issues and we update the condition for this behavior check
-    NSCAssert(!CGImageGetImageSource(imageRef), @"Animated Coder created CGImageRef should not retain CGImageSourceRef, which may cause thread-safe issue without lock");
+        extern CGImageSourceRef CGImageGetImageSource(CGImageRef);
+        NSCAssert(!CGImageGetImageSource(imageRef), @"Animated Coder created CGImageRef should not retain CGImageSourceRef, which may cause thread-safe issue without lock");
+    }
 #endif
     
 #if SD_UIKIT || SD_WATCH

SDWebImage/Core/SDImageLoader.m

@@ -47,10 +47,8 @@ UIImage * _Nullable SDImageLoaderDecodeImageData(NSData * _Nonnull imageData, NS
     CGFloat scale = [coderOptions[SDImageCoderDecodeScaleFactor] doubleValue];
     
     // Grab the image coder
-    id<SDImageCoder> imageCoder;
+    id<SDImageCoder> imageCoder = context[SDWebImageContextImageCoder];
-    if ([context[SDWebImageContextImageCoder] conformsToProtocol:@protocol(SDImageCoder)]) {
+    if (!imageCoder) {
-        imageCoder = context[SDWebImageContextImageCoder];
-    } else {
         imageCoder = [SDImageCodersManager sharedManager];
     }
     
@@ -81,12 +79,6 @@ UIImage * _Nullable SDImageLoaderDecodeImageData(NSData * _Nonnull imageData, NS
         if (lazyDecode) {
             // lazyDecode = NO means we should not forceDecode, highest priority
             shouldDecode = NO;
-        } else if ([image.class conformsToProtocol:@protocol(SDAnimatedImage)]) {
-            // `SDAnimatedImage` do not decode
-            shouldDecode = NO;
-        } else if (image.sd_isAnimated) {
-            // animated image do not decode
-            shouldDecode = NO;
         }
         if (shouldDecode) {
             image = [SDImageCoderHelper decodedImageWithImage:image];
@@ -120,7 +112,7 @@ UIImage * _Nullable SDImageLoaderDecodeProgressiveImageData(NSData * _Nonnull im
     if (!progressiveCoder) {
         id<SDProgressiveImageCoder> imageCoder = context[SDWebImageContextImageCoder];
         // Check the progressive coder if provided
-        if ([imageCoder conformsToProtocol:@protocol(SDProgressiveImageCoder)]) {
+        if ([imageCoder respondsToSelector:@selector(initIncrementalWithOptions:)]) {
             progressiveCoder = [[[imageCoder class] alloc] initIncrementalWithOptions:coderOptions];
         } else {
             // We need to create a new instance for progressive decoding to avoid conflicts
@@ -143,7 +135,7 @@ UIImage * _Nullable SDImageLoaderDecodeProgressiveImageData(NSData * _Nonnull im
     if (!decodeFirstFrame) {
         // check whether we should use `SDAnimatedImage`
         Class animatedImageClass = context[SDWebImageContextAnimatedImageClass];
-        if ([animatedImageClass isSubclassOfClass:[UIImage class]] && [animatedImageClass conformsToProtocol:@protocol(SDAnimatedImage)] && [progressiveCoder conformsToProtocol:@protocol(SDAnimatedImageCoder)]) {
+        if ([animatedImageClass isSubclassOfClass:[UIImage class]] && [animatedImageClass conformsToProtocol:@protocol(SDAnimatedImage)] && [progressiveCoder respondsToSelector:@selector(animatedImageFrameAtIndex:)]) {
             image = [[animatedImageClass alloc] initWithAnimatedCoder:(id<SDAnimatedImageCoder>)progressiveCoder scale:scale];
             if (image) {
                 // Progressive decoding does not preload frames
@@ -164,12 +156,6 @@ UIImage * _Nullable SDImageLoaderDecodeProgressiveImageData(NSData * _Nonnull im
         if (lazyDecode) {
             // lazyDecode = NO means we should not forceDecode, highest priority
             shouldDecode = NO;
-        } else if ([image.class conformsToProtocol:@protocol(SDAnimatedImage)]) {
-            // `SDAnimatedImage` do not decode
-            shouldDecode = NO;
-        } else if (image.sd_isAnimated) {
-            // animated image do not decode
-            shouldDecode = NO;
         }
         if (shouldDecode) {
             image = [SDImageCoderHelper decodedImageWithImage:image];

SDWebImage/Core/SDWebImageDownloader.m

@@ -353,9 +353,7 @@ static void * SDWebImageDownloaderContext = &SDWebImageDownloaderContext;
     
     // Operation Class
     Class operationClass = self.config.operationClass;
-    if (operationClass && [operationClass isSubclassOfClass:[NSOperation class]] && [operationClass conformsToProtocol:@protocol(SDWebImageDownloaderOperation)]) {
+    if (!operationClass) {
-        // Custom operation class
-    } else {
         operationClass = [SDWebImageDownloaderOperation class];
     }
     NSOperation<SDWebImageDownloaderOperation> *operation = [[operationClass alloc] initWithRequest:request inSession:self.session options:options context:context];

SDWebImage/Core/SDWebImageDownloaderConfig.m

@@ -7,6 +7,7 @@
  */
 
 #import "SDWebImageDownloaderConfig.h"
+#import "SDWebImageDownloaderOperation.h"
 
 static SDWebImageDownloaderConfig * _defaultDownloaderConfig;
 
@@ -48,5 +49,12 @@ static SDWebImageDownloaderConfig * _defaultDownloaderConfig;
     return config;
 }
 
+- (void)setOperationClass:(Class)operationClass {
+    if (operationClass) {
+        NSAssert([operationClass isSubclassOfClass:[NSOperation class]] && [operationClass conformsToProtocol:@protocol(SDWebImageDownloaderOperation)], @"Custom downloader operation class must subclass NSOperation and conform to `SDWebImageDownloaderOperation` protocol");
+    }
+    _operationClass = operationClass;
+}
+
 
 @end

SDWebImage/Core/SDWebImageManager.m

@@ -170,7 +170,7 @@ static id<SDImageLoader> _defaultImageLoader;
     id<SDImageTransformer> transformer = self.transformer;
     if (context[SDWebImageContextImageTransformer]) {
         transformer = context[SDWebImageContextImageTransformer];
-        if (![transformer conformsToProtocol:@protocol(SDImageTransformer)]) {
+        if ([transformer isEqual:NSNull.null]) {
             transformer = nil;
         }
     }
@@ -286,10 +286,8 @@ static id<SDImageLoader> _defaultImageLoader;
                             progress:(nullable SDImageLoaderProgressBlock)progressBlock
                            completed:(nullable SDInternalCompletionBlock)completedBlock {
     // Grab the image cache to use
-    id<SDImageCache> imageCache;
+    id<SDImageCache> imageCache = context[SDWebImageContextImageCache];
-    if ([context[SDWebImageContextImageCache] conformsToProtocol:@protocol(SDImageCache)]) {
+    if (!imageCache) {
-        imageCache = context[SDWebImageContextImageCache];
-    } else {
         imageCache = self.imageCache;
     }
     // Get the query cache type
@@ -338,14 +336,11 @@ static id<SDImageLoader> _defaultImageLoader;
                                     progress:(nullable SDImageLoaderProgressBlock)progressBlock
                                    completed:(nullable SDInternalCompletionBlock)completedBlock {
     // Grab the image cache to use, choose standalone original cache firstly
-    id<SDImageCache> imageCache;
+    id<SDImageCache> imageCache = context[SDWebImageContextOriginalImageCache];
-    if ([context[SDWebImageContextOriginalImageCache] conformsToProtocol:@protocol(SDImageCache)]) {
+    if (!imageCache) {
-        imageCache = context[SDWebImageContextOriginalImageCache];
-    } else {
         // if no standalone cache available, use default cache
-        if ([context[SDWebImageContextImageCache] conformsToProtocol:@protocol(SDImageCache)]) {
+        imageCache = context[SDWebImageContextImageCache];
-            imageCache = context[SDWebImageContextImageCache];
+        if (!imageCache) {
-        } else {
             imageCache = self.imageCache;
         }
     }
@@ -401,10 +396,8 @@ static id<SDImageLoader> _defaultImageLoader;
     }
     
     // Grab the image loader to use
-    id<SDImageLoader> imageLoader;
+    id<SDImageLoader> imageLoader = context[SDWebImageContextImageLoader];
-    if ([context[SDWebImageContextImageLoader] conformsToProtocol:@protocol(SDImageLoader)]) {
+    if (!imageLoader) {
-        imageLoader = context[SDWebImageContextImageLoader];
-    } else {
         imageLoader = self.imageLoader;
     }
     
@@ -488,7 +481,7 @@ static id<SDImageLoader> _defaultImageLoader;
                                 finished:(BOOL)finished
                                completed:(nullable SDInternalCompletionBlock)completedBlock {
     id<SDImageTransformer> transformer = context[SDWebImageContextImageTransformer];
-    if (![transformer conformsToProtocol:@protocol(SDImageTransformer)]) {
+    if ([transformer isEqual:NSNull.null]) {
         transformer = nil;
     }
     // transformer check
@@ -546,14 +539,11 @@ static id<SDImageLoader> _defaultImageLoader;
                                        finished:(BOOL)finished
                                       completed:(nullable SDInternalCompletionBlock)completedBlock {
     // Grab the image cache to use, choose standalone original cache firstly
-    id<SDImageCache> imageCache;
+    id<SDImageCache> imageCache = context[SDWebImageContextOriginalImageCache];
-    if ([context[SDWebImageContextOriginalImageCache] conformsToProtocol:@protocol(SDImageCache)]) {
+    if (!imageCache) {
-        imageCache = context[SDWebImageContextOriginalImageCache];
-    } else {
         // if no standalone cache available, use default cache
-        if ([context[SDWebImageContextImageCache] conformsToProtocol:@protocol(SDImageCache)]) {
+        imageCache = context[SDWebImageContextImageCache];
-            imageCache = context[SDWebImageContextImageCache];
+        if (!imageCache) {
-        } else {
             imageCache = self.imageCache;
         }
     }
@@ -605,10 +595,8 @@ static id<SDImageLoader> _defaultImageLoader;
                                  finished:(BOOL)finished
                                 completed:(nullable SDInternalCompletionBlock)completedBlock {
     // Grab the image cache to use
-    id<SDImageCache> imageCache;
+    id<SDImageCache> imageCache = context[SDWebImageContextImageCache];
-    if ([context[SDWebImageContextImageCache] conformsToProtocol:@protocol(SDImageCache)]) {
+    if (!imageCache) {
-        imageCache = context[SDWebImageContextImageCache];
-    } else {
         imageCache = self.imageCache;
     }
     BOOL waitStoreCache = SD_OPTIONS_CONTAINS(options, SDWebImageWaitStoreCache);
@@ -704,10 +692,8 @@ static id<SDImageLoader> _defaultImageLoader;
                               error:(nonnull NSError *)error
                             options:(SDWebImageOptions)options
                             context:(nullable SDWebImageContext *)context {
-    id<SDImageLoader> imageLoader;
+    id<SDImageLoader> imageLoader = context[SDWebImageContextImageLoader];
-    if ([context[SDWebImageContextImageLoader] conformsToProtocol:@protocol(SDImageLoader)]) {
+    if (!imageLoader) {
-        imageLoader = context[SDWebImageContextImageLoader];
-    } else {
         imageLoader = self.imageLoader;
     }
     // Check whether we should block failed url

SDWebImage/Core/UIView+WebCacheOperation.m

@@ -60,7 +60,7 @@ typedef NSMapTable<NSString *, id<SDWebImageOperation>> SDOperationsDictionary;
             operation = [operationDictionary objectForKey:key];
         }
         if (operation) {
-            if ([operation conformsToProtocol:@protocol(SDWebImageOperation)]) {
+            if ([operation respondsToSelector:@selector(cancel)]) {
                 [operation cancel];
             }
             @synchronized (self) {

Tests/Tests/SDWebImageDownloaderTests.m

@@ -84,7 +84,11 @@
     NSURL *imageURL2 = [NSURL URLWithString:kTestPNGURL];
     NSURL *imageURL3 = [NSURL URLWithString:kTestGIFURL];
     // we try to set a usual NSOperation as operation class. Should not work
-    downloader.config.operationClass = [NSOperation class];
+    @try {
+        downloader.config.operationClass = [NSOperation class];
+    } @catch (NSException *exception) {
+        expect(exception).notTo.beNil();
+    }
     SDWebImageDownloadToken *token = [downloader downloadImageWithURL:imageURL1 options:0 progress:nil completed:nil];
     NSOperation<SDWebImageDownloaderOperation> *operation = token.downloadOperation;
     expect([operation class]).to.equal([SDWebImageDownloaderOperation class]);