text: // Copyright (c) 2009 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  // -----------------------------------------------------------------------------
  // NOTE: If you change this file you need to touch renderer_resources.grd to
  // have your change take effect.
  // -----------------------------------------------------------------------------
  
  var chrome = chrome || {};
  (function () {
    native function OpenChannelToExtension(id);
    native function CloseChannel(portId);
    native function PostMessage(portId, msg);
    native function GetChromeHidden();
  
    var chromeHidden = GetChromeHidden();
  
    // Map of port IDs to port object.
    var ports = {};
  
    // Port object.  Represents a connection to another script context through
    // which messages can be passed.
    chrome.Port = function(portId) {
      this.portId_ = portId;
      this.onDisconnect = new chrome.Event();
      this.onMessage = new chrome.Event();
    };
  
    chromeHidden.Port = {};
  
    // Hidden port creation function.  We don't want to expose an API that lets
    // people add arbitrary port IDs to the port list.
    chromeHidden.Port.createPort = function(portId) {
      if (ports[portId]) {
        throw new Error("Port '" + portId + "' already exists.");
      }
      var port = new chrome.Port(portId);
      ports[portId] = port;
      chromeHidden.onUnload.addListener(function() {
        port.disconnect();
      });
      return port;
    }
  
    // Called by native code when a channel has been opened to this context.
    chromeHidden.Port.dispatchOnConnect = function(portId, tab, extensionId) {
      // Only create a new Port if someone is actually listening for a connection.
      // In addition to being an optimization, this also fixes a bug where if 2
      // channels were opened to and from the same process, closing one would
      // close both.
      var connectEvent = "channel-connect:" + extensionId;
      if (chromeHidden.Event.hasListener(connectEvent)) {
        var port = chromeHidden.Port.createPort(portId);
        if (tab) {
          tab = JSON.parse(tab);
        }
        port.tab = tab;
        chromeHidden.Event.dispatch(connectEvent, [port]);
      }
    };
  
    // Called by native code when a channel has been closed.
    chromeHidden.Port.dispatchOnDisconnect = function(portId) {
      var port = ports[portId];
      if (port) {
        port.onDisconnect.dispatch(port);
        delete ports[portId];
      }
    };
  
    // Called by native code when a message has been sent to the given port.
    chromeHidden.Port.dispatchOnMessage = function(msg, portId) {
      var port = ports[portId];
      if (port) {
        if (msg) {
          msg = JSON.parse(msg);
        }
        port.onMessage.dispatch(msg, port);
      }
    };
  
    // Sends a message asynchronously to the context on the other end of this
    // port.
    chrome.Port.prototype.postMessage = function(msg) {
      // JSON.stringify doesn't support a root object which is undefined.
      if (msg === undefined)
        msg = null;
      PostMessage(this.portId_, JSON.stringify(msg));
    };
  
    // Disconnects the port from the other end.
    chrome.Port.prototype.disconnect = function() {
      delete ports[this.portId_];
      CloseChannel(this.portId_);
    }
  
    // Extension object.
    chrome.Extension = function(id) {
      this.id_ = id;
      this.onConnect = new chrome.Event('channel-connect:' + id);
    };
  
    // Opens a message channel to the extension.  Returns a Port for
    // message passing.
    chrome.Extension.prototype.connect = function() {
      var portId = OpenChannelToExtension(this.id_);
      if (portId == -1)
        throw new Error("No such extension: '" + this.id_ + "'");
      return chromeHidden.Port.createPort(portId);
    };
  
    // Returns a resource URL that can be used to fetch a resource from this
    // extension.
    chrome.Extension.prototype.getURL = function(path) {
      return "chrome-extension://" + this.id_ + "/" + path;
    };
  
    chrome.self = chrome.self || {};
  })();
  