mirror of
https://github.com/shaka-project/shaka-player.git
synced 2026-06-15 16:06:41 +03:00
Jozef Chutka
ca299b2822
This adds a VTTCue polyfill for IE/Edge (3-arg TextTrackCue) and Toshiba dTV (6-arg TextTrackCue). Closes #635
112 lines
3.0 KiB
JavaScript
112 lines
3.0 KiB
JavaScript
/**
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* @license
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* Copyright 2016 Google Inc.
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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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*/
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goog.provide('shaka.polyfill.VTTCue');
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goog.require('shaka.log');
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goog.require('shaka.polyfill.register');
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/**
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* @namespace shaka.polyfill.VTTCue
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*
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* @summary A polyfill to provide VTTCue.
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*/
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/**
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* Install the polyfill if needed.
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*/
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shaka.polyfill.VTTCue.install = function() {
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if (window.VTTCue) {
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shaka.log.info('Using native VTTCue.');
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return;
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}
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if (!window.TextTrackCue) {
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shaka.log.error('VTTCue not available.');
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return;
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}
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var constructorLength = TextTrackCue.length;
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if (constructorLength == 3) {
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shaka.log.info('Using VTTCue polyfill from 3 argument TextTrackCue.');
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window.VTTCue = shaka.polyfill.VTTCue.from3ArgsTextTrackCue_;
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} else if (constructorLength == 6) {
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shaka.log.info('Using VTTCue polyfill from 6 argument TextTrackCue.');
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window.VTTCue = shaka.polyfill.VTTCue.from6ArgsTextTrackCue_;
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} else if (shaka.polyfill.VTTCue.canUse3ArgsTextTrackCue_()) {
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shaka.log.info('Using VTTCue polyfill from 3 argument TextTrackCue.');
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window.VTTCue = shaka.polyfill.VTTCue.from3ArgsTextTrackCue_;
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}
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};
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/**
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* Draft spec TextTrackCue with 3 constructor arguments.
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* See {@link https://goo.gl/ZXBWZi W3C Working Draft 25 October 2012}.
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*
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* @param {number} startTime
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* @param {number} endTime
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* @param {string} text
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* @return {TextTrackCue}
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* @private
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*/
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shaka.polyfill.VTTCue.from3ArgsTextTrackCue_ = function(startTime, endTime,
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text) {
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return new window.TextTrackCue(startTime, endTime, text);
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};
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/**
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* Draft spec TextTrackCue with 6 constructor arguments (5th & 6th are
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* optional).
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* See {@link https://goo.gl/AYFqUh W3C Working Draft 29 March 2012}.
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* Quoting the access to the TextTrackCue object to avoid the compiler
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* complaining.
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*
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* @param {number} startTime
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* @param {number} endTime
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* @param {string} text
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* @return {TextTrackCue}
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* @private
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*/
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shaka.polyfill.VTTCue.from6ArgsTextTrackCue_ = function(startTime, endTime,
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text) {
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var id = startTime + '-' + endTime + '-' + text;
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return new window['TextTrackCue'](id, startTime, endTime, text);
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};
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/**
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* IE10, IE11 and Edge returns TextTrackCue.length = 0 although it accepts 3
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* constructor arguments.
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*
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* @return {boolean}
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* @private
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*/
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shaka.polyfill.VTTCue.canUse3ArgsTextTrackCue_ = function() {
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try {
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return !!shaka.polyfill.VTTCue.from3ArgsTextTrackCue_(1, 2, '');
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} catch (error) {
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return false;
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}
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};
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shaka.polyfill.register(shaka.polyfill.VTTCue.install);
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