Issue 1663 - Made first-run page use an asynchronous messaging protocol

ext/content.js

Index: ext/content.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/ext/content.js
@@ -0,0 +1,154 @@
+/*
+ * This file is part of Adblock Plus <http://adblockplus.org/>,
+ * Copyright (C) 2006-2014 Eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * 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/>.
+ */
+
+(function(global)
+{
+  if (!global.ext)
+    global.ext = {};
+
+  function updateFromURL(data)
+  {
+    if (window.location.search)
+    {
+      var params = window.location.search.substr(1).split("&");
+      for (var i = 0; i < params.length; i++)
+      {
+        var parts = params[i].split("=", 2);
+        if (parts.length == 2 && parts[0] in data)
+          data[parts[0]] = decodeURIComponent(parts[1]);
+      }
+    }
+  }
+
+  var subscriptions =[
+    "https://easylist-downloads.adblockplus.org/easylistgermany+easylist.txt",
+    "https://easylist-downloads.adblockplus.org/exceptionrules.txt",
+    "https://easylist-downloads.adblockplus.org/fanboy-social.txt"
+  ];
+
+  var listenerFilter = null;
+
+  global.ext.backgroundPage = {
+    sendMessage: function(message, responseCallback)
+    {
+      var respond = function(response)
+      {
+        setTimeout(responseCallback.bind(responseCallback, response), 0);
+      };
+
+      var dispatchListenerNotification = function(action)
+      {
+        var match = /^subscription\.(.*)/.exec(action);
+        if (match && listenerFilter && listenerFilter.indexOf(match[1]) >= 0)
+        {
+          global.ext.onMessage._dispatch({
+            type: "subscriptions.listen",
+            action: match[1],
+            args: Array.prototype.slice.call(arguments, 1)
+          });
+        }
+      };
+
+      switch (message.type)
+      {
+        case "app.get":
+          if (message.what == "issues")
+          {
+            var response = {seenDataCorruption: false, filterlistsReinitialized: false};
+            updateFromURL(response);
+
+            var info = {platform: "gecko", platformVersion: "34.0", application: "firefox", applicationVersion: "34.0"};
+            updateFromURL(info);
+            response.legacySafariVersion = (info.platform == "safari" && (
+              parseInt(info.platformVersion, 10) < 6 ||  // beforeload breaks websites in Safari 5
+              info.platformVersion == "6.1" ||           // extensions are broken in 6.1 and 7.0
+              info.platformVersion == "7.0"));
+
+            respond(response);
+          }
+          else if (message.what == "doclink")
+            respond("https://adblockplus.org/redirect?link=" + encodeURIComponent(message.link));
+          else
+            respond(null);
+          break;
+        case "app.open":
+          if (message.what == "options")
+            window.open("http://example.com/options.html", "_blank");
+          break;
+        case "subscriptions.get":
+          respond(subscriptions);
+          break;
+        case "filters.blocked":
+          var params = {blockedURLs: ""};
+          updateFromURL(params);
+          var blocked = params.blockedURLs.split(",");
+          respond(blocked.indexOf(message.url) >= 0);
+          break;
+        case "subscriptions.toggle":
+          var index = subscriptions.indexOf(message.url);
+          if (index >= 0)
+          {
+            subscriptions.splice(index, 1);
+            dispatchListenerNotification("subscription.removed", message.url);
+          }
+          else
+          {
+            subscriptions.push(message.url);
+            dispatchListenerNotification("subscription.added", message.url);
+          }
+          break;
+        case "subscriptions.listen":
+          listenerFilter = message.filter;
+          break;
+      }
+    }
+  };
+
+  var EventTarget = function(cancelable)
+  {
+    this._listeners = [];
+    this._cancelable = cancelable;
+  };
+  EventTarget.prototype = {
+    addListener: function(listener)
+    {
+      if (this._listeners.indexOf(listener) == -1)
+        this._listeners.push(listener);
+    },
+    removeListener: function(listener)
+    {
+      var idx = this._listeners.indexOf(listener);
+      if (idx != -1)
+        this._listeners.splice(idx, 1);
+    },
+    _dispatch: function()
+    {
+      var result = null;
+
+      for (var i = 0; i < this._listeners.length; i++)
+      {
+        result = this._listeners[i].apply(null, arguments);
+
+        if (this._cancelable && result === false)
+          break;
+      }
+
+      return result;
+    }
+  };
+  global.ext.onMessage = new EventTarget();
+})(this);