extensions/renderer/resources/context_menus_handlers.js

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // Implementation of custom bindings for the contextMenus API.
   6 // This is used to implement the contextMenus API for extensions and for the
   7 // <webview> tag (see chrome_web_view_experimental.js).
   8
   9 var contextMenuNatives = requireNative('context_menus');
  10 var sendRequest = require('sendRequest').sendRequest;
  11 var Event = require('event_bindings').Event;
  12 var lastError = require('lastError');
  13
  14 // Add the bindings to the contextMenus API.
  15 function createContextMenusHandlers(isWebview) {
  16   var eventName = isWebview ? 'webViewInternal.contextMenus' : 'contextMenus';
  17   // Some dummy value for chrome.contextMenus instances.
  18   // Webviews use positive integers, and 0 to denote an invalid webview ID.
  19   // The following constant is -1 to avoid any conflicts between webview IDs and
  20   // extensions.
  21   var INSTANCEID_NON_WEBVIEW = -1;
  22
  23   // Generates a customCallback for a given method. |handleCallback| will be
  24   // invoked with |request.args| as parameters.
  25   function createCustomCallback(handleCallback) {
  26     return function(name, request, callback) {
  27       if (lastError.hasError(chrome)) {
  28         if (callback)
  29           callback();
  30         return;
  31       }
  32       var args = request.args;
  33       if (!isWebview) {
  34         // <webview>s have an extra item in front of the parameter list, which
  35         // specifies the viewInstanceId of the webview. This is used to hide
  36         // context menu events in one webview from another.
  37         // The non-webview chrome.contextMenus API is not called with such an
  38         // ID, so we prepend an ID to match the function signature.
  39         args = $Array.concat([INSTANCEID_NON_WEBVIEW], args);
  40       }
  41       $Function.apply(handleCallback, null, args);
  42       if (callback)
  43         callback();
  44     };
  45   }
  46
  47   var contextMenus = {};
  48   contextMenus.handlers = {};
  49   contextMenus.event = new Event(eventName);
  50
  51   contextMenus.getIdFromCreateProperties = function(createProperties) {
  52     if (typeof createProperties.id !== 'undefined')
  53       return createProperties.id;
  54     return createProperties.generatedId;
  55   };
  56
  57   contextMenus.handlersForId = function(instanceId, id) {
  58     if (!contextMenus.handlers[instanceId]) {
  59       contextMenus.handlers[instanceId] = {
  60         generated: {},
  61         string: {}
  62       };
  63     }
  64     if (typeof id === 'number')
  65       return contextMenus.handlers[instanceId].generated;
  66     return contextMenus.handlers[instanceId].string;
  67   };
  68
  69   contextMenus.ensureListenerSetup = function() {
  70     if (contextMenus.listening) {
  71       return;
  72     }
  73     contextMenus.listening = true;
  74     contextMenus.event.addListener(function(info) {
  75       var instanceId = INSTANCEID_NON_WEBVIEW;
  76       if (isWebview) {
  77         instanceId = info.webviewInstanceId;
  78         // Don't expose |webviewInstanceId| via the public API.
  79         delete info.webviewInstanceId;
  80       }
  81
  82       var id = info.menuItemId;
  83       var onclick = contextMenus.handlersForId(instanceId, id)[id];
  84       if (onclick) {
  85         $Function.apply(onclick, null, arguments);
  86       }
  87     });
  88   };
  89
  90   // To be used with apiFunctions.setHandleRequest
  91   var requestHandlers = {};
  92   // To be used with apiFunctions.setCustomCallback
  93   var callbacks = {};
  94
  95   requestHandlers.create = function() {
  96     var createProperties = isWebview ? arguments[1] : arguments[0];
  97     createProperties.generatedId = contextMenuNatives.GetNextContextMenuId();
  98     var optArgs = {
  99       customCallback: this.customCallback,
 100     };
 101     sendRequest(this.name, arguments, this.definition.parameters, optArgs);
 102     return contextMenus.getIdFromCreateProperties(createProperties);
 103   };
 104
 105   callbacks.create =
 106       createCustomCallback(function(instanceId, createProperties) {
 107     var id = contextMenus.getIdFromCreateProperties(createProperties);
 108     var onclick = createProperties.onclick;
 109     if (onclick) {
 110       contextMenus.ensureListenerSetup();
 111       contextMenus.handlersForId(instanceId, id)[id] = onclick;
 112     }
 113   });
 114
 115   callbacks.remove = createCustomCallback(function(instanceId, id) {
 116     delete contextMenus.handlersForId(instanceId, id)[id];
 117   });
 118
 119   callbacks.update =
 120       createCustomCallback(function(instanceId, id, updateProperties) {
 121     var onclick = updateProperties.onclick;
 122     if (onclick) {
 123       contextMenus.ensureListenerSetup();
 124       contextMenus.handlersForId(instanceId, id)[id] = onclick;
 125     } else if (onclick === null) {
 126       // When onclick is explicitly set to null, remove the event listener.
 127       delete contextMenus.handlersForId(instanceId, id)[id];
 128     }
 129   });
 130
 131   callbacks.removeAll = createCustomCallback(function(instanceId) {
 132     delete contextMenus.handlers[instanceId];
 133   });
 134
 135   return {
 136     requestHandlers: requestHandlers,
 137     callbacks: callbacks
 138   };
 139 }
 140
 141 exports.create = createContextMenusHandlers;