Merge custom bindings for context menus

extensions/renderer/resources/context_menus_handlers.js

+// Copyright 2015 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.
+
+// Implementation of custom bindings for the contextMenus API.
+// This is used to implement the contextMenus API for extensions and for the
+// <webview> tag (see chrome_web_view_experimental.js).
+
+var contextMenuNatives = requireNative('context_menus');
+var sendRequest = require('sendRequest').sendRequest;
+var Event = require('event_bindings').Event;
+var lastError = require('lastError');
+
+// Add the bindings to the contextMenus API.
+function createContextMenusHandlers(isWebview) {
+  var eventName = isWebview ? 'webViewInternal.contextMenus' : 'contextMenus';
+  // Some dummy value for chrome.contextMenus instances.
+  // Webviews use positive integers, and 0 to denote an invalid webview ID.
+  // The following constant is -1 to avoid any conflicts between webview IDs and
+  // extensions.
+  var INSTANCEID_NON_WEBVIEW = -1;
+
+  // Generates a customCallback for a given method. |handleCallback| will be
+  // invoked with |request.args| as parameters.
+  function createCustomCallback(handleCallback) {
+    return function(name, request, callback) {
+      if (lastError.hasError(chrome)) {
+        if (callback)
+          callback();
+        return;
+      }
+      var args = request.args;
+      if (!isWebview) {
+        // <webview>s have an extra item in front of the parameter list, which
+        // specifies the viewInstanceId of the webview. This is used to hide
+        // context menu events in one webview from another.
+        // The non-webview chrome.contextMenus API is not called with such an
+        // ID, so we prepend an ID to match the function signature.
+        args = $Array.concat([INSTANCEID_NON_WEBVIEW], args);
+      }
+      $Function.apply(handleCallback, null, args);
+      if (callback)
+        callback();
+    };
+  }
+
+  var contextMenus = {};
+  contextMenus.handlers = {};
+  contextMenus.event = new Event(eventName);
+
+  contextMenus.getIdFromCreateProperties = function(createProperties) {
+    if (typeof createProperties.id !== 'undefined')
+      return createProperties.id;
+    return createProperties.generatedId;
+  };
+
+  contextMenus.handlersForId = function(instanceId, id) {
+    if (!contextMenus.handlers[instanceId]) {
+      contextMenus.handlers[instanceId] = {
+        generated: {},
+        string: {}
+      };
+    }
+    if (typeof id === 'number')
+      return contextMenus.handlers[instanceId].generated;
+    return contextMenus.handlers[instanceId].string;
+  };
+
+  contextMenus.ensureListenerSetup = function() {
+    if (contextMenus.listening) {
+      return;
+    }
+    contextMenus.listening = true;
+    contextMenus.event.addListener(function(info) {
+      var instanceId = INSTANCEID_NON_WEBVIEW;
+      if (isWebview) {
+        instanceId = info.webviewInstanceId;
+        // Don't expose |webviewInstanceId| via the public API.
+        delete info.webviewInstanceId;
+      }
+
+      var id = info.menuItemId;
+      var onclick = contextMenus.handlersForId(instanceId, id)[id];
+      if (onclick) {
+        $Function.apply(onclick, null, arguments);
+      }
+    });
+  };
+
+  // To be used with apiFunctions.setHandleRequest
+  var requestHandlers = {};
+  // To be used with apiFunctions.setCustomCallback
+  var callbacks = {};
+
+  requestHandlers.create = function() {
+    var createProperties = isWebview ? arguments[1] : arguments[0];
+    createProperties.generatedId = contextMenuNatives.GetNextContextMenuId();
+    var optArgs = {
+      customCallback: this.customCallback,
+    };
+    sendRequest(this.name, arguments, this.definition.parameters, optArgs);
+    return contextMenus.getIdFromCreateProperties(createProperties);
+  };
+
+  callbacks.create =
+      createCustomCallback(function(instanceId, createProperties) {
+    var id = contextMenus.getIdFromCreateProperties(createProperties);
+    var onclick = createProperties.onclick;
+    if (onclick) {
+      contextMenus.ensureListenerSetup();
+      contextMenus.handlersForId(instanceId, id)[id] = onclick;
+    }
+  });
+
+  callbacks.remove = createCustomCallback(function(instanceId, id) {
+    delete contextMenus.handlersForId(instanceId, id)[id];
+  });
+
+  callbacks.update =
+      createCustomCallback(function(instanceId, id, updateProperties) {
+    var onclick = updateProperties.onclick;
+    if (onclick) {
+      contextMenus.ensureListenerSetup();
+      contextMenus.handlersForId(instanceId, id)[id] = onclick;
+    } else if (onclick === null) {
+      // When onclick is explicitly set to null, remove the event listener.
+      delete contextMenus.handlersForId(instanceId, id)[id];
+    }
+  });
+
+  callbacks.removeAll = createCustomCallback(function(instanceId) {
+    delete contextMenus.handlers[instanceId];
+  });
+
+  return {
+    requestHandlers: requestHandlers,
+    callbacks: callbacks
+  };
+}
+
+exports.create = createContextMenusHandlers;