From 7c82adae6171ea0a9bf96856e0bbb67108e1e121 Mon Sep 17 00:00:00 2001
From: "fischman@webrtc.org"
 <fischman@webrtc.org@4adac7df-926f-26a2-2b94-8c16560cd09d>
Date: Wed, 30 Apr 2014 00:17:47 +0000
Subject: [PATCH] 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@6028 4adac7df-926f-26a2-2b94-8c16560cd09d
---
 AUTHORS                                       |  1 +
 .../examples/ios/AppRTCDemo/APPRTCAppClient.m | 40 ++++++++-----------
 2 files changed, 18 insertions(+), 23 deletions(-)

diff --git a/AUTHORS b/AUTHORS
index 691601652e..d9bb54d551 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -3,6 +3,7 @@
 
 Anil Kumar <an1kumar@gmail.com>
 Ben Strong <bstrong@gmail.com>
+Bridger Maxwell <bridgeyman@gmail.com>
 Christophe Dumez <ch.dumez@samsung.com>
 Eric Rescorla, RTFM Inc.
 Jie Mao <maojie0924@gmail.com>
diff --git a/talk/examples/ios/AppRTCDemo/APPRTCAppClient.m b/talk/examples/ios/AppRTCDemo/APPRTCAppClient.m
index 9ac83ffc15..9ef0a7a74a 100644
--- a/talk/examples/ios/AppRTCDemo/APPRTCAppClient.m
+++ b/talk/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]];