Issue 4783 - Use Port API for the messageResponder

background.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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
@@ skipping 319 matching lines @@
     applicationVersion: "34.0",
     addonName: "adblockplus",
     addonVersion: "2.6.7"
   };
   updateFromURL(modules.info);
 
   modules.subscriptionInit = {
     reinitialized: params.filterlistsReinitialized
   };
 
+  modules.messaging = {
+    port: {
+      _eventEmitter: new EventEmitter(),

[Sebastian Noack, 2017/01/16 15:00:03]

Couldn't you do it like that:

  modules.messaging = {
    port: new EventEmitter()
  };

  window.addEventListener("message", event =>
  {
    // code from patch set #2 here but simply using
    // modules.messaging.port._listeners instead of messageListeners
  });

This way we wouldn't need to wrap the EventEmitter, neither do we export
private/prefixed APIs.

[kzar, 2017/01/16 15:16:31]

Done.

+      on(name, callback) { this._eventEmitter.on(name, callback); },
+      off(name, callback) { this._eventEmitter.off(name, callback); },
+      _onMessage(event)
+      {
+        if (event.data.type != "message")
+          return;
+        let message = event.data.payload;
+        let messageId = event.data.messageId;
+        let sender = {
+          page: new ext.Page(event.source)
+        };
+
+        function reply(message)
+        {
+          event.source.postMessage({
+            type: "response",
+            messageId: messageId,
+            payload: message
+          }, "*");
+        }
+
+        let port = modules.messaging.port;
+        let listeners = port._eventEmitter._listeners[message.type];
+        if (!listeners)
+          return;
+
+        for (let listener of listeners)
+        {
+          let response = listener(message, sender);
+          if (response && typeof response.then == "function")
+          {
+            response.then(
+              reply,
+              reason => {
+                console.error(reason);
+                reply(undefined);
+              }
+            );
+          }
+          else if (typeof response != "undefined")
+          {
+            reply(response);
+          }
+        }
+      }
+    }
+  };
+  window.addEventListener("message", modules.messaging.port._onMessage);
+
   global.Services = {
     vc: {
       compare: function(v1, v2)
       {
         return parseFloat(v1) - parseFloat(v2);
       }
     }
   };
 
   var filters = [
@@ skipping 128 matching lines @@
 
   if (params.safariContentBlocker)
   {
     global.safari = {
       extension: {
         setContentBlocker: function() {}
       }
     };
   }
 })(this);