add $browser.defer and $defer service and fix async xhr cache issue

- Closes #152 ($resource().query() sometimes calls callback before
  returning, and it shouldn't)
- add $browser.defer method
- add $defer service
- integrate $browser.defer with outstandingRequests counter in $browser
- fix all old tests that relied on buggy behavior

3 files changed, 83 insertions, 21 deletions

diff --git a/src/AngularPublic.js b/src/AngularPublic.js
index 98e0eed8..af572340 100644
--- a/src/AngularPublic.js
+++ b/src/AngularPublic.js
@@ -15,7 +15,8 @@ angularService('$browser', function($log){
         jqLite(window.document),
         jqLite(window.document.getElementsByTagName('head')[0]),
         XHR,
-        $log);
+        $log,
+        window.setTimeout);
     browserSingleton.startPoller(50, function(delay, fn){setTimeout(delay,fn);});
     browserSingleton.bind();
   }
diff --git a/src/Browser.js b/src/Browser.js
index 197cf1f4..94807a8c 100644
--- a/src/Browser.js
+++ b/src/Browser.js
@@ -8,7 +8,7 @@ var XHR = window.XMLHttpRequest || function () {
   throw new Error("This browser does not support XMLHttpRequest.");
 };
 
-function Browser(location, document, head, XHR, $log) {
+function Browser(location, document, head, XHR, $log, setTimeout) {
   var self = this;
   self.isMock = false;
 
@@ -19,6 +19,28 @@ function Browser(location, document, head, XHR, $log) {
   var outstandingRequestCount = 0;
   var outstandingRequestCallbacks = [];
 
+
+  /**
+   * Executes the `fn` function (supports currying) and decrements the `outstandingRequestCallbacks`
+   * counter. If the counter reaches 0, all the `outstandingRequestCallbacks` are executed.
+   */
+  function completeOutstandingRequest(fn) {
+    try {
+      fn.apply(null, slice.call(arguments, 1));
+    } finally {
+      outstandingRequestCount--;
+      if (outstandingRequestCount === 0) {
+        while(outstandingRequestCallbacks.length) {
+          try {
+            outstandingRequestCallbacks.pop()();
+          } catch (e) {
+            $log.error(e);
+          }
+        }
+      }
+    }
+  }
+
   /**
    * @workInProgress
    * @ngdoc method
@@ -58,19 +80,7 @@ function Browser(location, document, head, XHR, $log) {
       outstandingRequestCount ++;
       xhr.onreadystatechange = function() {
         if (xhr.readyState == 4) {
-          try {
-            callback(xhr.status || 200, xhr.responseText);
-          } finally {
-            outstandingRequestCount--;
-            if (outstandingRequestCount === 0) {
-              while(outstandingRequestCallbacks.length) {
-                try {
-                  outstandingRequestCallbacks.pop()();
-                } catch (e) {
-                }
-              }
-            }
-          }
+          completeOutstandingRequest(callback, xhr.status || 200, xhr.responseText);
         }
       };
       xhr.send(post || '');
@@ -250,6 +260,27 @@ function Browser(location, document, head, XHR, $log) {
     }
   };
 
+
+  /**
+   * @workInProgress
+   * @ngdoc
+   * @name angular.service.$browser#defer
+   * @methodOf angular.service.$browser
+   *
+   * @description
+   * Executes a fn asynchroniously via `setTimeout(fn, 0)`.
+   *
+   * Unlike when calling `setTimeout` directly, in test this function is mocked and instead of using
+   * `setTimeout` in tests, the fns are queued in an array, which can be programaticaly flushed via
+   * `$browser.defer.flush()`.
+   *
+   * @param {function()} fn A function, who's execution should be defered.
+   */
+  self.defer = function(fn) {
+    outstandingRequestCount++;
+    setTimeout(function() { completeOutstandingRequest(fn); }, 0);
+  };
+
   //////////////////////////////////////////////////////////////
   // Misc API
   //////////////////////////////////////////////////////////////
diff --git a/src/services.js b/src/services.js
index 91932b44..ef3de549 100644
--- a/src/services.js
+++ b/src/services.js
@@ -685,7 +685,7 @@ angularServiceInject('$route', function(location) {
  * @ngdoc service
  * @name angular.service.$xhr
  * @requires $browser
- * @requires $error
+ * @requires $xhr.error
  * @requires $log
  * 
  * @description
@@ -801,6 +801,36 @@ angularServiceInject('$xhr.bulk', function($xhr, $error, $log){
   return bulkXHR;
 }, ['$xhr', '$xhr.error', '$log']);
 
+
+/**
+ * @workInProgress
+ * @ngdoc service
+ * @name angular.service.$defer
+ * @requires $browser
+ * @requires $log
+ *
+ * @description
+ * Delegates to {@link angular.service.$browser.defer $browser.defer}, but wraps the `fn` function
+ * into a try/catch block and delegates any exceptions to
+ * {@link angular.services.$exceptionHandler $exceptionHandler} service.
+ *
+ * In tests you can use `$browser.defer.flush()` to flush the queue of deferred functions.
+ *
+ * @param {function()} fn A function, who's execution should be deferred.
+ */
+angularServiceInject('$defer', function($browser, $exceptionHandler) {
+  return function(fn) {
+    $browser.defer(function() {
+      try {
+        fn();
+      } catch(e) {
+        $exceptionHandler(e);
+      }
+    });
+  };
+}, ['$browser', '$exceptionHandler']);
+
+
 /**
  * @workInProgress
  * @ngdoc service
@@ -811,7 +841,7 @@ angularServiceInject('$xhr.bulk', function($xhr, $error, $log){
  * 
  * @example
  */
-angularServiceInject('$xhr.cache', function($xhr){
+angularServiceInject('$xhr.cache', function($xhr, $defer){
   var inflight = {}, self = this;
   function cache(method, url, post, callback, verifyCache){
     if (isFunction(post)) {
@@ -819,9 +849,9 @@ angularServiceInject('$xhr.cache', function($xhr){
       post = _null;
     }
     if (method == 'GET') {
-      var data;
-      if (data = cache.data[url]) {
-        callback(200, copy(data.value));
+      var data, dataCached;
+      if (dataCached = cache.data[url]) {
+        $defer(function() { callback(200, copy(dataCached.value)); });
         if (!verifyCache)
           return;
       }
@@ -853,7 +883,7 @@ angularServiceInject('$xhr.cache', function($xhr){
   cache.data = {};
   cache.delegate = $xhr;
   return cache;
-}, ['$xhr.bulk']);
+}, ['$xhr.bulk', '$defer']);
 
 
 /**