early return when image load canceled

SDWebImage/Core/UIView+WebCache.m

@@ -229,18 +229,14 @@ const int64_t SDWebImageProgressUnitCountUnknown = 1LL;
     } else if ([view isKindOfClass:[UIImageView class]]) {
         UIImageView *imageView = (UIImageView *)view;
         finalSetImageBlock = ^(UIImage *setImage, NSData *setImageData, SDImageCacheType setCacheType, NSURL *setImageURL) {
-            if (view.sd_latestOperationKey != nil) {
+            imageView.image = setImage;
-                imageView.image = setImage;
-            }
         };
     }
 #if SD_UIKIT
     else if ([view isKindOfClass:[UIButton class]]) {
         UIButton *button = (UIButton *)view;
         finalSetImageBlock = ^(UIImage *setImage, NSData *setImageData, SDImageCacheType setCacheType, NSURL *setImageURL) {
-            if (view.sd_latestOperationKey != nil) {
+            [button setImage:setImage forState:UIControlStateNormal];
-                [button setImage:setImage forState:UIControlStateNormal];
-            }
         };
     }
 #endif
@@ -248,9 +244,7 @@ const int64_t SDWebImageProgressUnitCountUnknown = 1LL;
     else if ([view isKindOfClass:[NSButton class]]) {
         NSButton *button = (NSButton *)view;
         finalSetImageBlock = ^(UIImage *setImage, NSData *setImageData, SDImageCacheType setCacheType, NSURL *setImageURL) {
-            if (view.sd_latestOperationKey != nil) {
+            button.image = setImage;
-                button.image = setImage;
-            }
         };
     }
 #endif
@@ -258,22 +252,38 @@ const int64_t SDWebImageProgressUnitCountUnknown = 1LL;
     if (transition) {
 #if SD_UIKIT
         [UIView transitionWithView:view duration:0 options:0 animations:^{
+            if (!view.sd_latestOperationKey) {
+                return;
+            }
             // 0 duration to let UIKit render placeholder and prepares block
             if (transition.prepares) {
                 transition.prepares(view, image, imageData, cacheType, imageURL);
             }
         } completion:^(BOOL finished) {
             [UIView transitionWithView:view duration:transition.duration options:transition.animationOptions animations:^{
+                if (!view.sd_latestOperationKey) {
+                    return;
+                }
                 if (finalSetImageBlock && !transition.avoidAutoSetImage) {
                     finalSetImageBlock(image, imageData, cacheType, imageURL);
                 }
                 if (transition.animations) {
                     transition.animations(view, image);
                 }
-            } completion:transition.completion];
+            } completion:^(BOOL finished) {
+                if (!view.sd_latestOperationKey) {
+                    return;
+                }
+                if (transition.completion) {
+                    transition.completion(finished);
+                }
+            }];
         }];
 #elif SD_MAC
         [NSAnimationContext runAnimationGroup:^(NSAnimationContext * _Nonnull prepareContext) {
+            if (!view.sd_latestOperationKey) {
+                return;
+            }
             // 0 duration to let AppKit render placeholder and prepares block
             prepareContext.duration = 0;
             if (transition.prepares) {
@@ -281,6 +291,9 @@ const int64_t SDWebImageProgressUnitCountUnknown = 1LL;
             }
         } completionHandler:^{
             [NSAnimationContext runAnimationGroup:^(NSAnimationContext * _Nonnull context) {
+                if (!view.sd_latestOperationKey) {
+                    return;
+                }
                 context.duration = transition.duration;
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wdeprecated-declarations"
@@ -302,6 +315,9 @@ const int64_t SDWebImageProgressUnitCountUnknown = 1LL;
                     transition.animations(view, image);
                 }
             } completionHandler:^{
+                if (!view.sd_latestOperationKey) {
+                    return;
+                }
                 if (transition.completion) {
                     transition.completion(YES);
                 }