Merge pull request #2986 from dreampiggy/feature_pass_set_operation_key

Feature pass the set operation key into context option from upstream. Fix the potential retain cycle if user use custom manager

SDWebImage/Core/UIView+WebCache.m

@@ -52,10 +52,19 @@ const int64_t SDWebImageProgressUnitCountUnknown = 1LL;
                      setImageBlock:(nullable SDSetImageBlock)setImageBlock
                           progress:(nullable SDImageLoaderProgressBlock)progressBlock
                          completed:(nullable SDInternalCompletionBlock)completedBlock {
-    context = [context copy]; // copy to avoid mutable object
+    if (context) {
+        // copy to avoid mutable object
+        context = [context copy];
+    } else {
+        context = [NSDictionary dictionary];
+    }
     NSString *validOperationKey = context[SDWebImageContextSetImageOperationKey];
     if (!validOperationKey) {
+        // pass through the operation key to downstream, which can used for tracing operation or image view class
         validOperationKey = NSStringFromClass([self class]);
+        SDWebImageMutableContext *mutableContext = [context mutableCopy];
+        mutableContext[SDWebImageContextSetImageOperationKey] = validOperationKey;
+        context = [mutableContext copy];
     }
     self.sd_latestOperationKey = validOperationKey;
     [self sd_cancelImageLoadOperationWithKey:validOperationKey];
@@ -83,6 +92,11 @@ const int64_t SDWebImageProgressUnitCountUnknown = 1LL;
         SDWebImageManager *manager = context[SDWebImageContextCustomManager];
         if (!manager) {
             manager = [SDWebImageManager sharedManager];
+        } else {
+            // remove this manager to avoid retain cycle (manger -> loader -> operation -> context -> manager)
+            SDWebImageMutableContext *mutableContext = [context mutableCopy];
+            mutableContext[SDWebImageContextCustomManager] = nil;
+            context = [mutableContext copy];
         }
         
         SDImageLoaderProgressBlock combinedProgressBlock = ^(NSInteger receivedSize, NSInteger expectedSize, NSURL * _Nullable targetURL) {

Tests/Tests/SDWebCacheCategoriesTests.m

@@ -350,6 +350,32 @@
     [self waitForExpectationsWithCommonTimeout];
 }
 
+- (void)testUIViewOperationKeyContextWorks {
+    XCTestExpectation *expectation = [self expectationWithDescription:@"UIView operation key context should pass through"];
+    
+    UIView *view = [[UIView alloc] init];
+    NSURL *originalImageURL = [NSURL URLWithString:kTestJPEGURL];
+    SDWebImageManager *customManager = [[SDWebImageManager alloc] initWithCache:SDImageCachesManager.sharedManager loader:SDImageLoadersManager.sharedManager];
+    customManager.optionsProcessor = [SDWebImageOptionsProcessor optionsProcessorWithBlock:^SDWebImageOptionsResult * _Nullable(NSURL * _Nullable url, SDWebImageOptions options, SDWebImageContext * _Nullable context) {
+        // expect manager does not exist, avoid retain cycle
+        expect(context[SDWebImageContextCustomManager]).beNil();
+        // expect operation key to be the image view class
+        expect(context[SDWebImageContextSetImageOperationKey]).equal(NSStringFromClass(view.class));
+        return [[SDWebImageOptionsResult alloc] initWithOptions:options context:context];
+    }];
+    [view sd_internalSetImageWithURL:originalImageURL
+                    placeholderImage:nil
+                             options:0
+                             context:@{SDWebImageContextCustomManager: customManager}
+                       setImageBlock:nil
+                            progress:nil
+                           completed:^(UIImage * _Nullable image, NSData * _Nullable data, NSError * _Nullable error, SDImageCacheType cacheType, BOOL finished, NSURL * _Nullable imageURL) {
+        [expectation fulfill];
+    }];
+    
+    [self waitForExpectationsWithCommonTimeout];
+}
+
 #pragma mark - Helper
 - (UIWindow *)window {
     if (!_window) {