| /** |
| * @license |
| * Copyright (C) 2016 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| (function() { |
| 'use strict'; |
| |
| const HLJS_PATH = 'bower_components/highlightjs/highlight.min.js'; |
| const DARK_THEME_PATH = 'styles/themes/dark-theme.html'; |
| |
| Polymer({ |
| is: 'gr-lib-loader', |
| _legacyUndefinedCheck: true, |
| |
| properties: { |
| _hljsState: { |
| type: Object, |
| |
| // NOTE: intended singleton. |
| value: { |
| configured: false, |
| loading: false, |
| callbacks: [], |
| }, |
| }, |
| }, |
| |
| /** |
| * Get the HLJS library. Returns a promise that resolves with a reference to |
| * the library after it's been loaded. The promise resolves immediately if |
| * it's already been loaded. |
| * @return {!Promise<Object>} |
| */ |
| getHLJS() { |
| return new Promise((resolve, reject) => { |
| // If the lib is totally loaded, resolve immediately. |
| if (this._getHighlightLib()) { |
| resolve(this._getHighlightLib()); |
| return; |
| } |
| |
| // If the library is not currently being loaded, then start loading it. |
| if (!this._hljsState.loading) { |
| this._hljsState.loading = true; |
| this._loadScript(this._getHLJSUrl()) |
| .then(this._onHLJSLibLoaded.bind(this)).catch(reject); |
| } |
| |
| this._hljsState.callbacks.push(resolve); |
| }); |
| }, |
| |
| /** |
| * Loads the dark theme document. Returns a promise that resolves with a |
| * custom-style DOM element. |
| * @return {!Promise<Element>} |
| * @suppress {checkTypes} |
| */ |
| getDarkTheme() { |
| return new Promise((resolve, reject) => { |
| (this.importHref || Polymer.importHref)( |
| this._getLibRoot() + DARK_THEME_PATH, () => { |
| const module = document.createElement('style', 'custom-style'); |
| module.setAttribute('include', 'dark-theme'); |
| resolve(module); |
| }); |
| }); |
| }, |
| |
| /** |
| * Execute callbacks awaiting the HLJS lib load. |
| */ |
| _onHLJSLibLoaded() { |
| const lib = this._getHighlightLib(); |
| this._hljsState.loading = false; |
| this.$.jsAPI.handleEvent(this.$.jsAPI.EventType.HIGHLIGHTJS_LOADED, { |
| hljs: lib, |
| }); |
| for (const cb of this._hljsState.callbacks) { |
| cb(lib); |
| } |
| this._hljsState.callbacks = []; |
| }, |
| |
| /** |
| * Get the HLJS library, assuming it has been loaded. Configure the library |
| * if it hasn't already been configured. |
| * @return {!Object} |
| */ |
| _getHighlightLib() { |
| const lib = window.hljs; |
| if (lib && !this._hljsState.configured) { |
| this._hljsState.configured = true; |
| |
| lib.configure({classPrefix: 'gr-diff gr-syntax gr-syntax-'}); |
| } |
| return lib; |
| }, |
| |
| /** |
| * Get the resource path used to load the application. If the application |
| * was loaded through a CDN, then this will be the path to CDN resources. |
| * @return {string} |
| */ |
| _getLibRoot() { |
| if (window.STATIC_RESOURCE_PATH) { |
| return window.STATIC_RESOURCE_PATH + '/'; |
| } |
| return '/'; |
| }, |
| |
| /** |
| * Load and execute a JS file from the lib root. |
| * @param {string} src The path to the JS file without the lib root. |
| * @return {Promise} a promise that resolves when the script's onload |
| * executes. |
| */ |
| _loadScript(src) { |
| return new Promise((resolve, reject) => { |
| const script = document.createElement('script'); |
| |
| if (!src) { |
| reject(new Error('Unable to load blank script url.')); |
| return; |
| } |
| |
| script.src = src; |
| script.onload = resolve; |
| script.onerror = reject; |
| Polymer.dom(document.head).appendChild(script); |
| }); |
| }, |
| |
| _getHLJSUrl() { |
| const root = this._getLibRoot(); |
| if (!root) { return null; } |
| return root + HLJS_PATH; |
| }, |
| }); |
| })(); |