feat($http): add support for aborting via timeout promises

If the timeout argument is a promise, abort the request when it is resolved.
Implemented by adding support to $httpBackend service and $httpBackend mock
service.

This api can also be used to explicitly abort requests while keeping the
communication between the deffered and promise unidirectional.

Closes #1159

2 files changed, 14 insertions, 8 deletions

diff --git a/src/ng/http.js b/src/ng/http.js
index 708a0650..fbdc89a5 100644
--- a/src/ng/http.js
+++ b/src/ng/http.js
@@ -548,7 +548,8 @@ function $HttpProvider() {
      *      GET request, otherwise if a cache instance built with
      *      {@link ng.$cacheFactory $cacheFactory}, this cache will be used for
      *      caching.
-     *    - **timeout** – `{number}` – timeout in milliseconds.
+     *    - **timeout** – `{number|Promise}` – timeout in milliseconds, or {@link ng.$q promise}
+     *      that should abort the request when resolved.
      *    - **withCredentials** - `{boolean}` - whether to to set the `withCredentials` flag on the
      *      XHR object. See {@link https://developer.mozilla.org/en/http_access_control#section_5
      *      requests with credentials} for more information.
@@ -927,7 +928,7 @@ function $HttpProvider() {
         }
 
         resolvePromise(response, status, headersString);
-        $rootScope.$apply();
+        if (!$rootScope.$$phase) $rootScope.$apply();
       }
 
 
diff --git a/src/ng/httpBackend.js b/src/ng/httpBackend.js
index 69ac5976..ed8404f9 100644
--- a/src/ng/httpBackend.js
+++ b/src/ng/httpBackend.js
@@ -107,20 +107,25 @@ function createHttpBackend($browser, XHR, $browserDefer, callbacks, rawDocument,
     }
 
     if (timeout > 0) {
-      var timeoutId = $browserDefer(function() {
-        status = -1;
-        jsonpDone && jsonpDone();
-        xhr && xhr.abort();
-      }, timeout);
+      var timeoutId = $browserDefer(timeoutRequest, timeout);
+    } else if (timeout && timeout.then) {
+      timeout.then(timeoutRequest);
     }
 
 
+    function timeoutRequest() {
+      status = -1;
+      jsonpDone && jsonpDone();
+      xhr && xhr.abort();
+    }
+
     function completeRequest(callback, status, response, headersString) {
       // URL_MATCH is defined in src/service/location.js
       var protocol = (url.match(SERVER_MATCH) || ['', locationProtocol])[1];
 
-      // cancel timeout
+      // cancel timeout and subsequent timeout promise resolution
       timeoutId && $browserDefer.cancel(timeoutId);
+      jsonpDone = xhr = null;
 
       // fix status code for file protocol (it's always 0)
       status = (protocol == 'file') ? (response ? 200 : 404) : status;