From 0b1954cacecdbf634651e42c7e2659eb8b54c676 Mon Sep 17 00:00:00 2001
From: Pieter De Baets <pieterdb@fb.com>
Date: Wed, 17 Aug 2016 10:34:16 -0700
Subject: [PATCH] Avoid dispatching network callbacks when already on the right
 queue

Reviewed By: mmmulani

Differential Revision: D3690133

fbshipit-source-id: a1769016a05b3163a3b1c93f448864aeaecc6e46
---
 Libraries/Network/RCTHTTPRequestHandler.m |  5 ++++
 Libraries/Network/RCTNetworkTask.m        | 35 +++++++++++++++--------
 2 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/Libraries/Network/RCTHTTPRequestHandler.m b/Libraries/Network/RCTHTTPRequestHandler.m
index 1def6d4c7..2d87bfe88 100644
--- a/Libraries/Network/RCTHTTPRequestHandler.m
+++ b/Libraries/Network/RCTHTTPRequestHandler.m
@@ -9,6 +9,8 @@
 
 #import "RCTHTTPRequestHandler.h"
 
+#import "RCTNetworking.h"
+
 @interface RCTHTTPRequestHandler () <NSURLSessionDataDelegate>
 
 @end
@@ -19,6 +21,8 @@
   NSURLSession *_session;
 }
 
+@synthesize bridge = _bridge;
+
 RCT_EXPORT_MODULE()
 
 - (void)invalidate
@@ -55,6 +59,7 @@ RCT_EXPORT_MODULE()
 
     NSOperationQueue *callbackQueue = [NSOperationQueue new];
     callbackQueue.maxConcurrentOperationCount = 1;
+    callbackQueue.underlyingQueue = [[_bridge networking] methodQueue];
     NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
     _session = [NSURLSession sessionWithConfiguration:configuration
                                              delegate:self
diff --git a/Libraries/Network/RCTNetworkTask.m b/Libraries/Network/RCTNetworkTask.m
index f354ab44a..5aafacb25 100644
--- a/Libraries/Network/RCTNetworkTask.m
+++ b/Libraries/Network/RCTNetworkTask.m
@@ -37,6 +37,8 @@
     _handler = handler;
     _callbackQueue = callbackQueue;
     _status = RCTNetworkTaskPending;
+
+    dispatch_queue_set_specific(callbackQueue, (__bridge void *)self, (__bridge void *)self, NULL);
   }
   return self;
 }
@@ -53,6 +55,15 @@ RCT_NOT_IMPLEMENTED(- (instancetype)init)
   _uploadProgressBlock = nil;
 }
 
+- (void)dispatchCallback:(dispatch_block_t)callback
+{
+  if (dispatch_get_specific((__bridge void *)self) == (__bridge void *)self) {
+    callback();
+  } else {
+    dispatch_async(_callbackQueue, callback);
+  }
+}
+
 - (void)start
 {
   if (_requestToken == nil) {
@@ -96,9 +107,9 @@ RCT_NOT_IMPLEMENTED(- (instancetype)init)
     _status = RCTNetworkTaskFinished;
     if (_completionBlock) {
       RCTURLRequestCompletionBlock completionBlock = _completionBlock;
-      dispatch_async(_callbackQueue, ^{
+      [self dispatchCallback:^{
         completionBlock(self->_response, nil, RCTErrorWithMessage(@"Invalid request token."));
-      });
+      }];
     }
     [self invalidate];
   }
@@ -114,9 +125,9 @@ RCT_NOT_IMPLEMENTED(- (instancetype)init)
   if (_uploadProgressBlock) {
     RCTURLRequestProgressBlock uploadProgressBlock = _uploadProgressBlock;
     int64_t length = _request.HTTPBody.length;
-    dispatch_async(_callbackQueue, ^{
+    [self dispatchCallback:^{
       uploadProgressBlock(bytesSent, length);
-    });
+    }];
   }
 }
 
@@ -129,9 +140,9 @@ RCT_NOT_IMPLEMENTED(- (instancetype)init)
   _response = response;
   if (_responseBlock) {
     RCTURLRequestResponseBlock responseBlock = _responseBlock;
-    dispatch_async(_callbackQueue, ^{
+    [self dispatchCallback:^{
       responseBlock(response);
-    });
+    }];
   }
 }
 
@@ -151,15 +162,15 @@ RCT_NOT_IMPLEMENTED(- (instancetype)init)
 
   if (_incrementalDataBlock) {
     RCTURLRequestIncrementalDataBlock incrementalDataBlock = _incrementalDataBlock;
-    dispatch_async(_callbackQueue, ^{
+    [self dispatchCallback:^{
       incrementalDataBlock(data, length, total);
-    });
+    }];
   }
   if (_downloadProgressBlock && total > 0) {
     RCTURLRequestProgressBlock downloadProgressBlock = _downloadProgressBlock;
-    dispatch_async(_callbackQueue, ^{
+    [self dispatchCallback:^{
       downloadProgressBlock(length, total);
-    });
+    }];
   }
 }
 
@@ -172,9 +183,9 @@ RCT_NOT_IMPLEMENTED(- (instancetype)init)
   _status = RCTNetworkTaskFinished;
   if (_completionBlock) {
     RCTURLRequestCompletionBlock completionBlock = _completionBlock;
-    dispatch_async(_callbackQueue, ^{
+    [self dispatchCallback:^{
       completionBlock(self->_response, self->_data, error);
-    });
+    }];
   }
   [self invalidate];
 }