content: /*
   * Copyright (C) 2017 The Android Open Source Project
   *
   * 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.
   */
  package com.google.android.exoplayer2.source.ads;
  
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.Timeline;
  import com.google.android.exoplayer2.source.ForwardingTimeline;
  import com.google.android.exoplayer2.util.Assertions;
  
  /**
   * A {@link Timeline} for sources that have ads.
   */
  /* package */ final class SinglePeriodAdTimeline extends ForwardingTimeline {
  
    private final AdPlaybackState adPlaybackState;
  
    /**
     * Creates a new timeline with a single period containing ads.
     *
     * @param contentTimeline The timeline of the content alongside which ads will be played. It must
     *     have one window and one period.
     * @param adPlaybackState The state of the period's ads.
     */
    public SinglePeriodAdTimeline(Timeline contentTimeline, AdPlaybackState adPlaybackState) {
      super(contentTimeline);
      Assertions.checkState(contentTimeline.getPeriodCount() == 1);
      Assertions.checkState(contentTimeline.getWindowCount() == 1);
      this.adPlaybackState = adPlaybackState;
    }
  
    @Override
    public Period getPeriod(int periodIndex, Period period, boolean setIds) {
      timeline.getPeriod(periodIndex, period, setIds);
      period.set(
          period.id,
          period.uid,
          period.windowIndex,
          period.durationUs,
          period.getPositionInWindowUs(),
          adPlaybackState);
      return period;
    }
  
    @Override
    public Window getWindow(int windowIndex, Window window, boolean setIds,
        long defaultPositionProjectionUs) {
      window = super.getWindow(windowIndex, window, setIds, defaultPositionProjectionUs);
      if (window.durationUs == C.TIME_UNSET) {
        window.durationUs = adPlaybackState.contentDurationUs;
      }
      return window;
    }
  
  }
  