shaka-player/lib/util/multi_map.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.util.MultiMap');


/**
 * A simple multimap template.
 * @constructor
 * @struct
 * @template T
 */
shaka.util.MultiMap = function() {
  /** @private {!Object.<string, !Array.<T>>} */
  this.map_ = {};
};


/**
 * Add a key, value pair to the map.
 * @param {string} key
 * @param {T} value
 */
shaka.util.MultiMap.prototype.push = function(key, value) {
  if (this.map_.hasOwnProperty(key)) {
    this.map_[key].push(value);
  } else {
    this.map_[key] = [value];
  }
};


/**
 * Get a list of values by key.
 * @param {string} key
 * @return {Array.<T>} or null if no such key exists.
 */
shaka.util.MultiMap.prototype.get = function(key) {
  let list = this.map_[key];
  // slice() clones the list so that it and the map can each be modified
  // without affecting the other.
  return list ? list.slice() : null;
};


/**
 * Get a list of all values.
 * @return {!Array.<T>}
 */
shaka.util.MultiMap.prototype.getAll = function() {
  let list = [];
  for (let key in this.map_) {
    list.push.apply(list, this.map_[key]);
  }
  return list;
};


/**
 * Remove a specific value, if it exists.
 * @param {string} key
 * @param {T} value
 */
shaka.util.MultiMap.prototype.remove = function(key, value) {
  let list = this.map_[key];
  if (!list) return;
  for (let i = 0; i < list.length; ++i) {
    if (list[i] == value) {
      list.splice(i, 1);
      --i;
    }
  }
};


/**
 * Clear all keys and values from the multimap.
 */
shaka.util.MultiMap.prototype.clear = function() {
  this.map_ = {};
};


/**
 * @param {function(string, !Array.<T>)} callback
 */
shaka.util.MultiMap.prototype.forEach = function(callback) {
  for (let key in this.map_) {
    callback(key, this.map_[key]);
  }
};