From 21ff7bd6ff6e66f6135f0337f72f3f89f9babac0 Mon Sep 17 00:00:00 2001
From: Olivier Poitrey <rs@dailymotion.com>
Date: Mon, 10 Dec 2012 15:08:56 +0100
Subject: [PATCH] Do not use GCD barrier for reading

---
 SDWebImage/SDWebImageDownloader.m | 38 ++++++++++++++++---------------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/SDWebImage/SDWebImageDownloader.m b/SDWebImage/SDWebImageDownloader.m
index ea44690..a436943 100644
--- a/SDWebImage/SDWebImageDownloader.m
+++ b/SDWebImage/SDWebImageDownloader.m
@@ -107,7 +107,7 @@ static NSString *const kCompletedCallbackKey = @"completed";
         {
             if (!wself) return;
             SDWebImageDownloader *sself = wself;
-            NSArray *callbacksForURL = [sself callbacksForURL:url remove:NO];
+            NSArray *callbacksForURL = [sself callbacksForURL:url];
             for (NSDictionary *callbacks in callbacksForURL)
             {
                 SDWebImageDownloaderProgressBlock callback = callbacks[kProgressCallbackKey];
@@ -118,7 +118,11 @@ static NSString *const kCompletedCallbackKey = @"completed";
         {
             if (!wself) return;
             SDWebImageDownloader *sself = wself;
-            NSArray *callbacksForURL = [sself callbacksForURL:url remove:finished];
+            NSArray *callbacksForURL = [sself callbacksForURL:url];
+            if (finished)
+            {
+                [sself removeCallbacksForURL:url];
+            }
             for (NSDictionary *callbacks in callbacksForURL)
             {
                 SDWebImageDownloaderCompletedBlock callback = callbacks[kCompletedCallbackKey];
@@ -129,7 +133,8 @@ static NSString *const kCompletedCallbackKey = @"completed";
         {
             if (!wself) return;
             SDWebImageDownloader *sself = wself;
-            [sself callbacksForURL:url remove:YES];
+            [sself callbacksForURL:url];
+            [sself removeCallbacksForURL:url];
         }];
         [self.downloadQueue addOperation:operation];
     }];
@@ -163,25 +168,22 @@ static NSString *const kCompletedCallbackKey = @"completed";
     });
 }
 
-- (NSArray *)callbacksForURL:(NSURL *)url remove:(BOOL)remove
+- (NSArray *)callbacksForURL:(NSURL *)url
 {
     __block NSArray *callbacksForURL;
-    if (remove)
+    dispatch_sync(self.barrierQueue, ^
     {
-        dispatch_barrier_sync(self.barrierQueue, ^
-        {
-            callbacksForURL = self.URLCallbacks[url];
-            [self.URLCallbacks removeObjectForKey:url];
-        });
-    }
-    else
-    {
-        dispatch_sync(self.barrierQueue, ^
-        {
-            callbacksForURL = self.URLCallbacks[url];
-        });
-    }
+        callbacksForURL = self.URLCallbacks[url];
+    });
     return callbacksForURL;
 }
 
+- (void)removeCallbacksForURL:(NSURL *)url
+{
+    dispatch_barrier_async(self.barrierQueue, ^
+    {
+        [self.URLCallbacks removeObjectForKey:url];
+    });
+}
+
 @end