Added JS-based XMLHttpRequest implementation

lib/compat.js

Index: lib/compat.js
===================================================================
--- a/lib/compat.js
+++ b/lib/compat.js
@@ -12,17 +12,16 @@
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 // TODO: These need to be defined properly
 var window = this;
-function XMLHttpRequest() {};
 function requestFileSystem() {};
 
 //
 // Module framework stuff
 //
 
 function require(module)
 {
@@ -273,23 +272,138 @@ FakeTimer.prototype =
         Cu.reportError(e);
       }
       me.scheduleTimeout();
     }, this.delay);
   }
 };
 
 //
-// Add a channel property to XMLHttpRequest, Synchronizer needs it
+// Fake XMLHttpRequest implementation
 //
 
-XMLHttpRequest.prototype.channel =
+function XMLHttpRequest()
 {
-  status: -1,
-  notificationCallbacks: {},
-  loadFlags: 0,
-  INHIBIT_CACHING: 0,
-  VALIDATE_ALWAYS: 0,
-  QueryInterface: function()
+  this._requestHeaders = {};
+  this._loadHandlers = [];
+  this._errorHandlers = [];
+};
+XMLHttpRequest.prototype =
+{
+  _url: null,
+  _requestHeaders: null,
+  _responseHeaders: null,
+  _loadHandlers: null,
+  _errorHandlers: null,
+  onload: null,
+  onerror: null,
+  status: 0,
+  readyState: 0,
+  responseText: null,
+
+  addEventListener: function(eventName, handler, capture)
   {
-    return this;
+    var list;
+    if (eventName == "load")
+      list = this._loadHandlers;
+    else if (eventName == "error")
+      list = this._errorHandlers;
+    else
+      throw new Error("Event type " + eventName + " not supported");
+
+    if (list.indexOf(handler) < 0)
+      list.push(handler);
+  },
+
+  removeEventListener: function(eventName, handler, capture)
+  {
+    var list;
+    if (eventName == "load")
+      list = this._loadHandlers;
+    else if (eventName == "error")
+      list = this._errorHandlers;
+    else
+      throw new Error("Event type " + eventName + " not supported");
+
+    var index = list.indexOf(handler);
+    if (index >= 0)
+      list.splice(index, 1);
+  },
+
+  open: function(method, url, async, user, password)
+  {
+    if (method != "GET")
+      throw new Error("Only GET requests are currently supported");
+    if (typeof async != "undefined" && !async)
+      throw new Error("Sync requests are not supported");
+    if (typeof user != "undefined" || typeof password != "undefined")
+      throw new Error("User authentification is not supported");
+    if (this.readyState != 0)
+      throw new Error("Already opened");
+
+    this.readyState = 1;
+    this._url = url;
+  },
+
+  send: function(data)
+  {
+    if (this.readyState != 1)
+      throw new Error("XMLHttpRequest.send() is being called before XMLHttpRequest.open()");
+    if (typeof data != "undefined" && data)
+      throw new Error("Sending data to server is not supported");
+
+    this.readyState = 3;
+    window._webRequest.GET(this._url, this._requestHeaders, function(result)
+    {
+      this.channel.status = result.status;
+      this.status = result.responseStatus;
+      this.responseText = result.responseText;
+      this._responseHeaders = result.responseHeaders;
+      this.readyState = 4;
+
+      // Notify event listeners
+      const NS_OK = 0;
+      var eventName = (this.channel.status == NS_OK ? "load" : "error");
+      var event = {type: eventName};
+
+      if (this["on" + eventName])
+        this.onload.call(this, event);
+
+      var list = this["_" + eventName + "Handlers"];
+      for (var i = 0; i < list.length; i++)
+        list[i].call(this, event);
+    }.bind(this));
+  },
+
+  overrideMimeType: function(mime)
+  {
+  },
+
+  setRequestHeader: function(name, value)
+  {
+    if (this.readyState > 1)
+      throw new Error("Cannot set request header after sending");
+
+    this._requestHeaders[name] = value;
+  },
+
+  getResponseHeader: function(name)
+  {
+    name = name.toLowerCase();
+    if (!this._responseHeaders || !this._responseHeaders.hasOwnProperty(name))
+      return null;
+    else
+      return this._responseHeaders[name];
+  },
+
+  channel:
+  {
+    status: -1,
+    notificationCallbacks: {},
+    loadFlags: 0,
+    INHIBIT_CACHING: 0,
+    VALIDATE_ALWAYS: 0,
+    QueryInterface: function()
+    {
+      return this;
+    }
   }
 };