e7a51875e6
Tapping the "Show Diffs" link in the change view to display all of a change's diffs inline spawns several asynchronous syntax highlighting processes. Sometimes (especially for long file lists and slower HLJS download rates) multiple highlight processes would request HLJS before it had been loaded, resulting in multiple load/definitions of the library. Occasionally this would result in a JS exception. With this change, the HLJS loader functionality of GR-SYNTAX-LAYER is separated into the GR-SYNTAX-LIB-LOADER component. This component employs a singleton property to track state across multiple lib requests behind a promise interface. Tests are updated. Change-Id: I673998d406a33afa158e04c4dbb91fe31442d527
94 lines
2.7 KiB
JavaScript
94 lines
2.7 KiB
JavaScript
// Copyright (C) 2016 The Android Open Source Project
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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(function() {
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'use strict';
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var HLJS_PATH = 'bower_components/highlightjs/highlight.min.js';
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var LIB_ROOT_PATTERN = /(.+\/)elements\/gr-app\.html/;
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Polymer({
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is: 'gr-syntax-lib-loader',
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properties: {
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_state: {
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type: Object,
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// NOTE: intended singleton.
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value: {
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loaded: false,
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loading: false,
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callbacks: [],
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},
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}
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},
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get: function() {
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return new Promise(function(resolve) {
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// If the lib is totally loaded, resolve immediately.
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if (this._state.loaded) {
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resolve(this._getHighlightLib());
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return;
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}
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// If the library is not currently being loaded, then start loading it.
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if (!this._state.loading) {
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this._state.loading = true;
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this._loadHLJS().then(this._onLibLoaded.bind(this));
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}
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this._state.callbacks.push(resolve);
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}.bind(this));
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},
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_onLibLoaded: function() {
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var lib = this._getHighlightLib();
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this._state.loaded = true;
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this._state.loading = false;
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this._state.callbacks.forEach(function(cb) { cb(lib); });
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this._state.callbacks = [];
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},
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_getHighlightLib: function() {
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return window.hljs;
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},
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_configureHighlightLib: function() {
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this._getHighlightLib().configure(
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{classPrefix: 'gr-diff gr-syntax gr-syntax-'});
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},
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_getLibRoot: function() {
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if (this._cachedLibRoot) { return this._cachedLibRoot; }
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return this._cachedLibRoot = document.head
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.querySelector('link[rel=import][href$="gr-app.html"]')
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.href
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.match(LIB_ROOT_PATTERN)[1];
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},
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_cachedLibRoot: null,
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_loadHLJS: function() {
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return new Promise(function(resolve) {
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var script = document.createElement('script');
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script.src = this._getLibRoot() + HLJS_PATH;
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script.onload = function() {
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this._configureHighlightLib();
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resolve();
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}.bind(this);
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Polymer.dom(document.head).appendChild(script);
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}.bind(this));
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},
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});
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})();
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