Issue 1663 - Emulate background page and implement proper message responder

messageResponder.js

Index: messageResponder.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/messageResponder.js
@@ -0,0 +1,138 @@
+/*
+ * 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)
+{
+  var subscriptionKeys = ["disabled", "homepage", "lastSuccess", "title", "url", "downloadStatus"];
+  function convertSubscription(subscription)
+  {
+    var result = {};
+    for (var i = 0; i < subscriptionKeys.length; i++)
+      result[subscriptionKeys[i]] = subscription[subscriptionKeys[i]]
+    return result;
+  }
+
+  var changeListeners = null;
+  function onFilterChange(action)
+  {
+    var parts = action.split(".", 2);
+    var type;
+    if (parts.length == 1)
+    {
+      type = "app";
+      action = parts[0];
+    }
+    else
+    {
+      type = parts[0];
+      action = parts[1];
+    }
+
+    var args = Array.prototype.slice.call(arguments, 1).map(function(arg)
+    {
+      if (arg instanceof Subscription)
+        return convertSubscription(arg);
+      else
+        return arg;
+    });
+
+    for (var i = 0; i < changeListeners.length; i++)
+    {
+      if (changeListeners[i].type == type && changeListeners[i].filter.indexOf(action) >= 0)
+      {
+        changeListeners[i].page.sendMessage({
+          type: changeListeners[i].messageType,
+          action: action,
+          args: args
+        });
+      }
+    }
+  };
+
+  ext.onMessage.addListener(function(message, sender, callback)
+  {
+    switch (message.type)
+    {
+      case "app.doclink":
+        callback(Utils.getDocLink(message.args[0]));
+        break;
+      case "app.info":
+        callback(require("info"));
+        break;
+      case "app.issues":
+        callback({
+          seenDataCorruption: "seenDataCorruption" in global ? global.seenDataCorruption : false,
+          filterlistsReinitialized: "filterlistsReinitialized" in global ? global.filterlistsReinitialized : false
+        });
+        break;
+      case "app.options":
+        if (typeof UI != "undefined")
+          UI.openFiltersDialog();
+        else
+          global.openOptions();
+        break;
+      case "subscriptions.get":
+        callback(FilterStorage.subscriptions.map(convertSubscription));
+        break;
+      case "filters.blocked":
+        var filter = defaultMatcher.matchesAny(message.url, message.requestType, message.docDomain, message.thirdParty);
+        callback(filter instanceof BlockingFilter);
+        break;
+      case "subscriptions.toggle":
+        var subscription = Subscription.fromURL(message.url);
+        if (subscription.url in FilterStorage.knownSubscriptions && !subscription.disabled)
+          FilterStorage.removeSubscription(subscription);
+        else
+        {
+          subscription.disabled = false;
+          subscription.title = message.title;
+          subscription.homepage = message.homepage;
+          FilterStorage.addSubscription(subscription);
+          if (!subscription.lastDownload)
+            Synchronizer.execute(subscription);
+        }
+        break;
+      case "subscriptions.listen":
+        if (!changeListeners)
+        {
+          changeListeners = [];
+          FilterNotifier.addListener(onFilterChange);
+        }
+        changeListeners.push({
+          type: "subscription",
+          filter: message.filter,
+          messageType: message.type,
+          page: sender.page
+        });
+        break;
+      case "removePage":
+        if (!changeListeners)
+          return;
+
+        for (var i = 0; i < changeListeners.length; i++)
+          if (changeListeners[i].page.equals(sender.page))
+            changeListeners.splice(i--, 1);
+
+        if (!changeListeners.length)
+        {
+          changeListeners = null;
+          FilterNotifier.removeListener(onFilterChange);
+        }
+        break;
+    }
+  });
+})(this);