AppRTCDemo was blocking the main thread for network requests. This fixes it by making the background queue serial instead of using @synchronize to make the background operations serial.

R=fischman@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/16379004

Patch from Bridger Maxwell <bridgeyman@gmail.com>.

git-svn-id: http://webrtc.googlecode.com/svn/trunk/talk@6028 4adac7df-926f-26a2-2b94-8c16560cd09d

1 files changed, 17 insertions, 23 deletions

diff --git a/examples/ios/AppRTCDemo/APPRTCAppClient.m b/examples/ios/AppRTCDemo/APPRTCAppClient.m
index 9ac83ff..9ef0a7a 100644
--- a/examples/ios/AppRTCDemo/APPRTCAppClient.m
+++ b/examples/ios/AppRTCDemo/APPRTCAppClient.m
@@ -56,7 +56,8 @@
   if (self = [super init]) {
     _ICEServerDelegate = delegate;
     _messageHandler = handler;
-    _backgroundQueue = dispatch_queue_create("RTCBackgroundQueue", NULL);
+    _backgroundQueue = dispatch_queue_create("RTCBackgroundQueue",
+                                             DISPATCH_QUEUE_SERIAL);
     _sendQueue = [NSMutableArray array];
     // Uncomment to see Request/Response logging.
     // _verboseLogging = YES;
@@ -72,11 +73,22 @@
 }
 
 - (void)sendData:(NSData*)data {
-  @synchronized(self) {
-    [self maybeLogMessage:@"Send message"];
+  [self maybeLogMessage:@"Send message"];
+
+  dispatch_async(self.backgroundQueue, ^{
     [self.sendQueue addObject:[data copy]];
-  }
-  [self requestQueueDrainInBackground];
+
+    if ([self.postMessageUrl length] < 1) {
+      return;
+    }
+    for (NSData* data in self.sendQueue) {
+      NSString* url =
+          [NSString stringWithFormat:@"%@/%@",
+                    self.baseURL, self.postMessageUrl];
+      [self sendData:data withUrl:url];
+    }
+    [self.sendQueue removeAllObjects];
+  });
 }
 
 #pragma mark - Internal methods
@@ -133,24 +145,6 @@
   }
 }
 
-- (void)requestQueueDrainInBackground {
-  dispatch_async(self.backgroundQueue, ^(void) {
-      // TODO(hughv): This can block the UI thread.  Fix.
-      @synchronized(self) {
-        if ([self.postMessageUrl length] < 1) {
-          return;
-        }
-        for (NSData* data in self.sendQueue) {
-          NSString* url =
-            [NSString stringWithFormat:@"%@/%@",
-                      self.baseURL, self.postMessageUrl];
-          [self sendData:data withUrl:url];
-        }
-        [self.sendQueue removeAllObjects];
-      }
-    });
-}
-
 - (void)sendData:(NSData*)data withUrl:(NSString*)url {
   NSMutableURLRequest* request =
       [NSMutableURLRequest requestWithURL:[NSURL URLWithString:url]];