Merge pull request #2997 from dreampiggy/black_list_error_code

Mark the black list formal error code, support remove the failed URL from black list

SDWebImage/Core/SDWebImageError.h

@@ -19,6 +19,7 @@ typedef NS_ERROR_ENUM(SDWebImageErrorDomain, SDWebImageError) {
     SDWebImageErrorInvalidURL = 1000, // The URL is invalid, such as nil URL or corrupted URL
     SDWebImageErrorBadImageData = 1001, // The image data can not be decoded to image, or the image data is empty
     SDWebImageErrorCacheNotModified = 1002, // The remote location specify that the cached image is not modified, such as the HTTP response 304 code. It's useful for `SDWebImageRefreshCached`
+    SDWebImageErrorBlackListed = 1003, // The URL is blacklisted because of unrecoverable failsure marked by downloader (such as 404), you can use `.retryFailed` option to avoid this
     SDWebImageErrorInvalidDownloadOperation = 2000, // The image download operation is invalid, such as nil operation or unexpected error occur when operation initialized
     SDWebImageErrorInvalidDownloadStatusCode = 2001, // The image download response a invalid status code. You can check the status code in error's userInfo under `SDWebImageErrorDownloadStatusCodeKey`
     SDWebImageErrorCancelled = 2002, // The image loading operation is cancelled before finished, during either async disk cache query, or waiting before actual network request. For actual network request error, check `NSURLErrorDomain` error domain and code.

SDWebImage/Core/SDWebImageManager.h

@@ -261,6 +261,17 @@ SDWebImageManager *manager = [SDWebImageManager sharedManager];
  */
 - (void)cancelAll;
 
+/**
+ * Remove the specify URL from failed black list.
+ * @param url The failed URL.
+ */
+- (void)removeFailedURL:(nonnull NSURL *)url;
+
+/**
+ * Remove all the URL from failed black list.
+ */
+- (void)removeAllFailedURLs;
+
 /**
  * Return the cache key for a given URL, does not considerate transformer or thumbnail.
  * @note This method does not have context option, only use the url and manager level cacheKeyFilter to generate the cache key.

SDWebImage/Core/SDWebImageManager.m

@@ -194,7 +194,9 @@ static id<SDImageLoader> _defaultImageLoader;
     }
 
     if (url.absoluteString.length == 0 || (!(options & SDWebImageRetryFailed) && isFailedUrl)) {
-        [self callCompletionBlockForOperation:operation completion:completedBlock error:[NSError errorWithDomain:SDWebImageErrorDomain code:SDWebImageErrorInvalidURL userInfo:@{NSLocalizedDescriptionKey : @"Image url is nil"}] url:url];
+        NSString *description = isFailedUrl ? @"Image url is blacklisted" : @"Image url is nil";
+        NSInteger code = isFailedUrl ? SDWebImageErrorBlackListed : SDWebImageErrorInvalidURL;
+        [self callCompletionBlockForOperation:operation completion:completedBlock error:[NSError errorWithDomain:SDWebImageErrorDomain code:code userInfo:@{NSLocalizedDescriptionKey : description}] url:url];
         return operation;
     }
 
@@ -226,6 +228,21 @@ static id<SDImageLoader> _defaultImageLoader;
     return isRunning;
 }
 
+- (void)removeFailedURL:(NSURL *)url {
+    if (!url) {
+        return;
+    }
+    SD_LOCK(self.failedURLsLock);
+    [self.failedURLs removeObject:url];
+    SD_UNLOCK(self.failedURLsLock);
+}
+
+- (void)removeAllFailedURLs {
+    SD_LOCK(self.failedURLsLock);
+    [self.failedURLs removeAllObjects];
+    SD_UNLOCK(self.failedURLsLock);
+}
+
 #pragma mark - Private
 
 // Query normal cache process