Returning error in setImage completedBlock if the url was nil. Added dispatch_main_async_safe macro. Fixes #505

Author: bpoplauschi

SDWebImage/MKAnnotationView+WebCache.m

@@ -60,6 +60,13 @@ - (void)sd_setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder
             });
         }];
         objc_setAssociatedObject(self, &operationKey, operation, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
+    } else {
+        dispatch_main_async_safe(^{
+            NSError *error = [NSError errorWithDomain:@"SDWebImageErrorDomain" code:-1 userInfo:@{NSLocalizedDescriptionKey : @"Trying to load a nil url"}];
+            if (completedBlock) {
+                completedBlock(nil, error, SDImageCacheTypeNone, url);
+            }
+        });
     }
 }
 

SDWebImage/SDWebImageCompat.h

@@ -56,7 +56,13 @@ extern UIImage *SDScaledImageForKey(NSString *key, UIImage *image);
 #define dispatch_main_sync_safe(block)\
     if ([NSThread isMainThread]) {\
         block();\
-    }\
-    else {\
+    } else {\
         dispatch_sync(dispatch_get_main_queue(), block);\
     }
+
+#define dispatch_main_async_safe(block)\
+    if ([NSThread isMainThread]) {\
+        block();\
+    } else {\
+        dispatch_async(dispatch_get_main_queue(), block);\
+    }

SDWebImage/UIButton+WebCache.m

@@ -17,8 +17,7 @@ @implementation UIButton (WebCache)
 - (NSURL *)currentImageURL {
     NSURL *url = self.imageURLStorage[@(self.state)];
 
-    if (!url)
-    {
+    if (!url) {
         url = self.imageURLStorage[@(UIControlStateNormal)];
     }
 
@@ -57,6 +56,13 @@ - (void)sd_setImageWithURL:(NSURL *)url forState:(UIControlState)state placehold
     if (!url) {
         [self.imageURLStorage removeObjectForKey:@(state)];
 
+        dispatch_main_async_safe(^{
+            NSError *error = [NSError errorWithDomain:@"SDWebImageErrorDomain" code:-1 userInfo:@{NSLocalizedDescriptionKey : @"Trying to load a nil url"}];
+            if (completedBlock) {
+                completedBlock(nil, error, SDImageCacheTypeNone, url);
+            }
+        });
+        
         return;
     }
 
@@ -120,6 +126,13 @@ - (void)sd_setBackgroundImageWithURL:(NSURL *)url forState:(UIControlState)state
             });
         }];
         objc_setAssociatedObject(self, &operationKey, operation, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
+    } else {
+        dispatch_main_async_safe(^{
+            NSError *error = [NSError errorWithDomain:@"SDWebImageErrorDomain" code:-1 userInfo:@{NSLocalizedDescriptionKey : @"Trying to load a nil url"}];
+            if (completedBlock) {
+                completedBlock(nil, error, SDImageCacheTypeNone, url);
+            }
+        });
     }
 }
 

SDWebImage/UIImageView+HighlightedWebCache.m

@@ -49,6 +49,13 @@ - (void)sd_setHighlightedImageWithURL:(NSURL *)url options:(SDWebImageOptions)op
                                      });
         }];
         objc_setAssociatedObject(self, &operationKey, operation, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
+    } else {
+        dispatch_main_async_safe(^{
+            NSError *error = [NSError errorWithDomain:@"SDWebImageErrorDomain" code:-1 userInfo:@{NSLocalizedDescriptionKey : @"Trying to load a nil url"}];
+            if (completedBlock) {
+                completedBlock(nil, error, SDImageCacheTypeNone, url);
+            }
+        });
     }
 }
 

SDWebImage/UIImageView+WebCache.m

@@ -69,6 +69,13 @@ - (void)sd_setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder
             });
         }];
         objc_setAssociatedObject(self, &operationKey, operation, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
+    } else {
+        dispatch_main_async_safe(^{
+            NSError *error = [NSError errorWithDomain:@"SDWebImageErrorDomain" code:-1 userInfo:@{NSLocalizedDescriptionKey : @"Trying to load a nil url"}];
+            if (completedBlock) {
+                completedBlock(nil, error, SDImageCacheTypeNone, url);
+            }
+        });
     }
 }