From c7a444f4a7f1f03c99feda48b81ada08027a00ef Mon Sep 17 00:00:00 2001
From: DreamPiggy <lizhuoli1126@126.com>
Date: Wed, 2 Aug 2017 17:14:37 +0800
Subject: [PATCH] Fix CFRelease on NULL if CGImageSourceRef create failed

Fix CFRelease on NULL if CGImageSourceRef create failed, this may happen on progressive download with wrong image data
---
 SDWebImage/SDWebImageDownloaderOperation.m | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/SDWebImage/SDWebImageDownloaderOperation.m b/SDWebImage/SDWebImageDownloaderOperation.m
index 6c7dd55f..b8c78ba4 100644
--- a/SDWebImage/SDWebImageDownloaderOperation.m
+++ b/SDWebImage/SDWebImageDownloaderOperation.m
@@ -376,7 +376,9 @@ didReceiveResponse:(NSURLResponse *)response
             }
         }
 
-        CFRelease(imageSource);
+        if (imageSource) {
+            CFRelease(imageSource);
+        }
     }
 
     for (SDWebImageDownloaderProgressBlock progressBlock in [self callbacksForKey:kProgressCallbackKey]) {