Source: streaming/utils/LiveEdgeFinder.js

/**
 * The copyright in this software is being made available under the BSD License,
 * included below. This software may be subject to other third party and contributor
 * rights, including patent rights, and no such rights are granted under this license.
 *
 * Copyright (c) 2013, Dash Industry Forum.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *  * Redistributions of source code must retain the above copyright notice, this
 *  list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright notice,
 *  this list of conditions and the following disclaimer in the documentation and/or
 *  other materials provided with the distribution.
 *  * Neither the name of Dash Industry Forum nor the names of its
 *  contributors may be used to endorse or promote products derived from this software
 *  without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS AS IS AND ANY
 *  EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 *  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 *  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 *  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 *  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 *  POSSIBILITY OF SUCH DAMAGE.
 */
import FactoryMaker from '../../core/FactoryMaker';

/**
 * @param {Object} config
 * @returns {{initialize: initialize, getLiveEdge: getLiveEdge, reset: reset}|*}
 * @constructor
 */
function LiveEdgeFinder(config) {

    let instance;
    let timelineConverter = config.timelineConverter;
    let streamProcessor = config.streamProcessor;

    function checkConfig() {
        if (!timelineConverter || !timelineConverter.hasOwnProperty('getExpectedLiveEdge') || !streamProcessor || !streamProcessor.hasOwnProperty('getCurrentRepresentationInfo')) {
            throw new Error('Missing config parameter(s)');
        }
    }

    function getLiveEdge() {
        checkConfig();
        const representationInfo = streamProcessor.getCurrentRepresentationInfo();
        let liveEdge = representationInfo.DVRWindow.end;
        if (representationInfo.useCalculatedLiveEdgeTime) {
            liveEdge = timelineConverter.getExpectedLiveEdge();
            timelineConverter.setClientTimeOffset(liveEdge - representationInfo.DVRWindow.end);
        }
        return liveEdge;
    }

    function reset() {
        timelineConverter = null;
        streamProcessor = null;
    }

    instance = {
        getLiveEdge: getLiveEdge,
        reset: reset
    };

    return instance;
}

LiveEdgeFinder.__dashjs_factory_name = 'LiveEdgeFinder';
export default FactoryMaker.getClassFactory(LiveEdgeFinder);