shaka-player/lib/hls/hls_utils.js

DASH/EME video player library

/**
 * @license
 * Copyright 2016 Google Inc.
 *
 * 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.
 */

goog.provide('shaka.hls.Utils');

goog.require('shaka.util.ManifestParserUtils');


/**
 *
 * @param {!Array.<!shaka.hls.Tag>} tags
 * @param {!string} name
 * @return {!Array.<!shaka.hls.Tag>}
 */
shaka.hls.Utils.filterTagsByName = function(tags, name) {
  return tags.filter(function(tag) {
    return tag.name == name;
  });
};


/**
 *
 * @param {!Array.<!shaka.hls.Tag>} tags
 * @param {!string} name
 * @return {?shaka.hls.Tag}
 */
shaka.hls.Utils.getFirstTagWithName = function(tags, name) {
  var tagsWithName = shaka.hls.Utils.filterTagsByName(tags, name);
  if (!tagsWithName.length) return null;

  return tagsWithName[0];
};


/**
 * Expects an array of EXT-X-MEDIA tags. Returns the first tag that
 * has given media type and group id.
 *
 * @param {!Array.<!shaka.hls.Tag>} tags
 * @param {!string} type
 * @param {!string} groupId
 * @return {!Array<!shaka.hls.Tag>}
 */
shaka.hls.Utils.findMediaTags = function(tags, type, groupId) {
  return tags.filter(function(tag) {
    var typeAttr = tag.getAttribute('TYPE');
    var groupIdAttr = tag.getAttribute('GROUP-ID');
    return typeAttr.value == type && groupIdAttr.value == groupId;
  });
};


/**
 * @param {!string} parentAbsoluteUri
 * @param {!string} uri
 * @return {!string}
 */
shaka.hls.Utils.constructAbsoluteUri = function(parentAbsoluteUri, uri) {
  var uris = shaka.util.ManifestParserUtils.resolveUris(
      [parentAbsoluteUri], [uri]);

  return uris[0];
};


/**
 * Matches a string to an HLS comment format and returns the result.
 *
 * @param {!string} line
 * @return {boolean}
 */
shaka.hls.Utils.isComment = function(line) {
  return /^#(?!EXT)/m.test(line);
};