Merge pull request #3420 from dreampiggy/fix_5.13_retain_cycle_web_context

Quick fix the issue that UIImage.sd_decodeOptions cause retain cycle when pass custom cache in context option

SDWebImage/Core/SDImageCacheDefine.m

@@ -13,6 +13,37 @@
 #import "UIImage+Metadata.h"
 #import "SDInternalMacros.h"
 
+static NSArray<NSString *>* GetKnownContextOptions(void) {
+    static NSArray<NSString *> *knownContextOptions;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        knownContextOptions =
+        [NSArray arrayWithObjects:
+         SDWebImageContextSetImageOperationKey,
+         SDWebImageContextCustomManager,
+         SDWebImageContextImageCache,
+         SDWebImageContextImageLoader,
+         SDWebImageContextImageCoder,
+         SDWebImageContextImageTransformer,
+         SDWebImageContextImageScaleFactor,
+         SDWebImageContextImagePreserveAspectRatio,
+         SDWebImageContextImageThumbnailPixelSize,
+         SDWebImageContextQueryCacheType,
+         SDWebImageContextStoreCacheType,
+         SDWebImageContextOriginalQueryCacheType,
+         SDWebImageContextOriginalStoreCacheType,
+         SDWebImageContextOriginalImageCache,
+         SDWebImageContextAnimatedImageClass,
+         SDWebImageContextDownloadRequestModifier,
+         SDWebImageContextDownloadResponseModifier,
+         SDWebImageContextDownloadDecryptor,
+         SDWebImageContextCacheKeyFilter,
+         SDWebImageContextCacheSerializer
+         , nil];
+    });
+    return knownContextOptions;
+}
+
 SDImageCoderOptions * _Nonnull SDGetDecodeOptionsFromContext(SDWebImageContext * _Nullable context, SDWebImageOptions options, NSString * _Nonnull cacheKey) {
     BOOL decodeFirstFrame = SD_OPTIONS_CONTAINS(options, SDWebImageDecodeFirstFrameOnly);
     NSNumber *scaleValue = context[SDWebImageContextImageScaleFactor];
@@ -34,7 +65,10 @@ SDImageCoderOptions * _Nonnull SDGetDecodeOptionsFromContext(SDWebImageContext *
     mutableCoderOptions[SDImageCoderDecodeScaleFactor] = @(scale);
     mutableCoderOptions[SDImageCoderDecodePreserveAspectRatio] = preserveAspectRatioValue;
     mutableCoderOptions[SDImageCoderDecodeThumbnailPixelSize] = thumbnailSizeValue;
-    mutableCoderOptions[SDImageCoderWebImageContext] = context;
+    // Hack to remove all known context options before SDWebImage 5.14.0
+    SDImageCoderMutableOptions *mutableContext = [NSMutableDictionary dictionaryWithDictionary:context];
+    [mutableContext removeObjectsForKeys:GetKnownContextOptions()];
+    mutableCoderOptions[SDImageCoderWebImageContext] = [mutableContext copy];
     SDImageCoderOptions *coderOptions = [mutableCoderOptions copy];
     
     return coderOptions;

SDWebImage/Core/SDImageCoder.h

@@ -91,7 +91,9 @@ FOUNDATION_EXPORT SDImageCoderOption _Nonnull const SDImageCoderEncodeEmbedThumb
  A SDWebImageContext object which hold the original context options from top-level API. (SDWebImageContext)
  This option is ignored for all built-in coders and take no effect.
  But this may be useful for some custom coders, because some business logic may dependent on things other than image or image data information only.
+ Only the unknown context from top-level API (See SDWebImageDefine.h) may be passed in during image loading.
  See `SDWebImageContext` for more detailed information.
+ @warning This option will be removed in 5.14.0
  */
 FOUNDATION_EXPORT SDImageCoderOption _Nonnull const SDImageCoderWebImageContext API_DEPRECATED("The coder component will be seperated from Core subspec in the future. Update your code to not rely on this context option.", macos(10.10, API_TO_BE_DEPRECATED), ios(8.0, API_TO_BE_DEPRECATED), tvos(9.0, API_TO_BE_DEPRECATED), watchos(2.0, API_TO_BE_DEPRECATED));
 

Tests/Tests/SDWebImageManagerTests.m

@@ -538,6 +538,18 @@
     [self waitForExpectationsWithTimeout:kAsyncTestTimeout * 5 handler:nil];
 }
 
+- (void)test20ThatContextPassedToLoaderDoesNotContainsBuiltIn {
+    XCTestExpectation *expectation = [self expectationWithDescription:@"The SDImageCoderWebImageContext should contains only unknown context to avoid retain cycle"];
+    NSURL *url = [NSURL URLWithString:@"http://via.placeholder.com/502x502.png"];
+    [SDWebImageManager.sharedManager loadImageWithURL:url options:0 context:@{SDWebImageContextImageScaleFactor : @(2), @"Foo": @"Bar"} progress:nil completed:^(UIImage * _Nullable image, NSData * _Nullable data, NSError * _Nullable error, SDImageCacheType cacheType, BOOL finished, NSURL * _Nullable imageURL) {
+        SDImageCoderOptions *decodeOptions = image.sd_decodeOptions;
+        SDWebImageContext *retrievedContext = decodeOptions[SDImageCoderWebImageContext];
+        expect(retrievedContext[@"Foo"]).equal(@"Bar");
+        [expectation fulfill];
+    }];
+    [self waitForExpectationsWithCommonTimeout];
+}
+
 - (NSString *)testJPEGPath {
     NSBundle *testBundle = [NSBundle bundleForClass:[self class]];
     return [testBundle pathForResource:@"TestImage" ofType:@"jpg"];