ui/file_manager/file_manager/cws_widget/cws_webview_client.js

// Copyright 2013 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.

class CWSContainerClient extends cr.EventTarget {
  /**
   * @param {WebView} webView Web View tag.
   * @param {number} width Width of the CWS widget.
   * @param {number} height Height of the CWS widget.
   * @param {string} url Share Url for an entry.
   * @param {string} target Target (scheme + host + port) of the widget.
   * @param {Object<*>} options Options to be sent to the dialog host.
   * @param {!CWSWidgetContainerPlatformDelegate} delegate Delegate for
   *     accessing Chrome platform APIs.
   */
  constructor(webView, width, height, url, target, options, delegate) {
    super();

    /** @private {!CWSWidgetContainerPlatformDelegate} */
    this.delegate_ = delegate;
    this.webView_ = webView;
    this.width_ = width;
    this.height_ = height;
    this.url_ = url;
    this.target_ = target;
    this.options_ = options;

    this.loaded_ = false;
    this.loading_ = false;

    this.onMessageBound_ = this.onMessage_.bind(this);
    this.onLoadStopBound_ = this.onLoadStop_.bind(this);
    this.onLoadAbortBound_ = this.onLoadAbort_.bind(this);
  }

  /**
   * Handles messages from the widget
   * @param {Event} event Message event.
   * @private
   */
  onMessage_(event) {
    if (event.origin != this.target_) {
      return;
    }

    const data = event.data;
    switch (data['message']) {
      case 'widget_loaded':
        this.onWidgetLoaded_();
        break;
      case 'widget_load_failed':
        this.onWidgetLoadFailed_();
        break;
      case 'before_install':
        this.sendInstallRequest_(data['item_id']);
        break;
      case 'after_install':
        this.sendInstallDone_(data['item_id']);
        break;
      default:
        console.error('Unexpected message: ' + data['message'], data);
    }
  }

  /**
   * Called when receiving 'loadstop' event from the <webview>.
   * @param {Event} event Message event.
   * @private
   */
  onLoadStop_(event) {
    if (this.url_ == this.webView_.src && !this.loaded_) {
      this.loaded_ = true;
      this.postInitializeMessage_();
    }
  }

  /**
   * Called when the widget is loaded successfully.
   * @private
   */
  onWidgetLoaded_() {
    cr.dispatchSimpleEvent(this, CWSContainerClient.Events.LOADED);
  }

  /**
   * Called when the widget is failed to load.
   * @private
   */
  onWidgetLoadFailed_() {
    this.sendWidgetLoadFailed_();
  }

  /**
   * Called when receiving the 'loadabort' event from <webview>.
   * @param {Event} event Message event.
   * @private
   */
  onLoadAbort_(event) {
    this.sendWidgetLoadFailed_();
  }

  /**
   * Called when the installation is completed from the suggest-app dialog.
   *
   * @param {boolean} result True if the installation is success, false if
   *     failed.
   * @param {string} itemId Item id to be installed.
   */
  onInstallCompleted(result, itemId) {
    if (result) {
      this.postInstallSuccessMessage_(itemId);
    } else {
      this.postInstallFailureMessage_(itemId);
    }
  }

  /**
   * Send the fail message to the suggest-app dialog.
   * @private
   */
  sendWidgetLoadFailed_() {
    cr.dispatchSimpleEvent(this, CWSContainerClient.Events.LOAD_FAILED);
  }

  /**
   * Send the install request to the suggest-app dialog.
   *
   * @param {string} itemId Item id to be installed.
   * @private
   */
  sendInstallRequest_(itemId) {
    const event = new Event(CWSContainerClient.Events.REQUEST_INSTALL);
    event.itemId = itemId;
    this.dispatchEvent(event);
  }

  /**
   * Notifies the suggest-app dialog that the item installation is completed.
   *
   * @param {string} itemId The installed item ID.
   * @private
   */
  sendInstallDone_(itemId) {
    const event = new Event(CWSContainerClient.Events.INSTALL_DONE);
    event.itemId = itemId;
    this.dispatchEvent(event);
  }

  /**
   * Send the 'install_failure' message to the widget.
   *
   * @param {string} itemId Item id to be installed.
   * @private
   */
  postInstallFailureMessage_(itemId) {
    const message = {message: 'install_failure', item_id: itemId, v: 1};

    this.postMessage_(message);
  }

  /**
   * Send the 'install_success' message to the widget.
   *
   * @param {string} itemId Item id to be installed.
   * @private
   */
  postInstallSuccessMessage_(itemId) {
    const message = {message: 'install_success', item_id: itemId, v: 1};

    this.postMessage_(message);
  }

  /**
   * Send the 'initialize' message to the widget.
   * @private
   */
  postInitializeMessage_() {
    new Promise((fulfill, reject) => {
      this.delegate_.getInstalledItems(
          /**
           * @param {?Array<!string>} items Installed items.
           *     Null on error.
           */
          items => {
            if (!items) {
              reject('Failed to retrive installed items.');
              return;
            }
            fulfill(items);
          });
    })
        .then(/**
               * @param {!Array<string>} preinstalledExtensionIDs
               */
              preinstalledExtensionIDs => {
                const message = {
                  message: 'initialize',
                  hl: this.delegate_.strings.UI_LOCALE,
                  width: this.width_,
                  height: this.height_,
                  preinstalled_items: preinstalledExtensionIDs,
                  v: 1
                };

                if (this.options_) {
                  Object.keys(this.options_).forEach(key => {
                    message[key] = this.options_[key];
                  });
                }

                this.postMessage_(message);
              });
  }

  /**
   * Send a message to the widget. This method shouldn't be called directly,
   * should from more specified posting function (eg. postXyzMessage_()).
   *
   * @param {Object} message Message object to be posted.
   * @private
   */
  postMessage_(message) {
    if (!this.webView_.contentWindow) {
      return;
    }

    this.webView_.contentWindow.postMessage(message, this.target_);
  }

  /**
   * Loads the page to <webview>. Can be called only once.
   */
  load() {
    if (this.loading_ || this.loaded_) {
      throw new Error('Already loaded.');
    }
    this.loading_ = true;
    this.loaded_ = false;

    window.addEventListener('message', this.onMessageBound_);
    this.webView_.addEventListener('loadstop', this.onLoadStopBound_);
    this.webView_.addEventListener('loadabort', this.onLoadAbortBound_);
    this.webView_.setAttribute('src', this.url_);
  }

  /**
   * Aborts loading of the embedded dialog and performs cleanup.
   */
  abort() {
    window.removeEventListener('message', this.onMessageBound_);
    this.webView_.removeEventListener('loadstop', this.onLoadStopBound_);
    this.webView_.removeEventListener('loadabort', this.onLoadAbortBound_);
    this.webView_.stop();
  }

  /**
   * Cleans the dialog by removing all handlers.
   */
  dispose() {
    this.abort();
  }
}

/**
 * Events CWSContainerClient fires
 *
 * @enum {string}
 * @const
 */
CWSContainerClient.Events = {
  LOADED: 'CWSContainerClient.Events.LOADED',
  LOAD_FAILED: 'CWSContainerClient.Events.LOAD_FAILED',
  REQUEST_INSTALL: 'CWSContainerClient.Events.REQUEST_INSTALL',
  INSTALL_DONE: 'CWSContainerClient.Events.INSTALL_DONE'
};
Object.freeze(CWSContainerClient.Events);