问刷新exoplayer中的媒体源

EN

public final class DynamicMediaSource implements MediaSource {

    private List<MediaSource> mediaSources;
    private SparseArray<Timeline> timelines;
    private SparseArray<Object> manifests;
    private Map<MediaPeriod, Integer> sourceIndexByMediaPeriod;
    private SparseArray<Boolean> duplicateFlags;
    private boolean isRepeatOneAtomic;

    private Listener listener;
    private DynamicTimeline timeline;

    /**
     * @param mediaSources The {@link MediaSource}s to concatenate. It is valid for the same
     *     {@link MediaSource} instance to be present more than once in the array.
     */
    public DynamicMediaSource(List<MediaSource> mediaSources) {
        this(false, mediaSources);
    }

    /**
     * @param isRepeatOneAtomic Whether the concatenated media source shall be treated as atomic
     *     (i.e., repeated in its entirety) when repeat mode is set to {@code Player.REPEAT_MODE_ONE}.
     * @param mediaSources The {@link MediaSource}s to concatenate. It is valid for the same
     *     {@link MediaSource} instance to be present more than once in the array.
     */
    public DynamicMediaSource(boolean isRepeatOneAtomic, List<MediaSource> mediaSources) {
        for (MediaSource mediaSource : mediaSources) {
            Assertions.checkNotNull(mediaSource);
        }
        this.mediaSources = mediaSources;
        this.isRepeatOneAtomic = isRepeatOneAtomic;
        timelines = new SparseArray<Timeline>();
        manifests = new SparseArray<Object>();
        sourceIndexByMediaPeriod = new HashMap<>();
        duplicateFlags = buildDuplicateFlags(mediaSources);
    }

    @Override
    public void prepareSource(ExoPlayer player, boolean isTopLevelSource, Listener listener) {
        this.listener = listener;
        for (int i = 0; i < mediaSources.size(); i++) {
            if (!duplicateFlags.get(i)) {
                final int index = i;
                mediaSources.get(i).prepareSource(player, false, new Listener() {
                    @Override
                    public void onSourceInfoRefreshed(Timeline timeline, Object manifest) {
                        handleSourceInfoRefreshed(index, timeline, manifest);
                    }
                });
            }
        }
    }

    @Override
    public void maybeThrowSourceInfoRefreshError() throws IOException {
        for (int i = 0; i < mediaSources.size(); i++) {
            if (!duplicateFlags.get(i)) {
                mediaSources.get(i).maybeThrowSourceInfoRefreshError();
            }
        }
    }

    @Override
    public MediaPeriod createPeriod(MediaPeriodId id, Allocator allocator) {
        int sourceIndex = timeline.getChildIndexByPeriodIndex(id.periodIndex);
        MediaPeriodId periodIdInSource =
            new MediaPeriodId(id.periodIndex - timeline.getFirstPeriodIndexByChildIndex(sourceIndex));
        MediaPeriod mediaPeriod = mediaSources.get(sourceIndex).createPeriod(periodIdInSource, allocator);
        sourceIndexByMediaPeriod.put(mediaPeriod, sourceIndex);
        return mediaPeriod;
    }

    @Override
    public void releasePeriod(MediaPeriod mediaPeriod) {
        int sourceIndex = sourceIndexByMediaPeriod.get(mediaPeriod);
        sourceIndexByMediaPeriod.remove(mediaPeriod);
        mediaSources.get(sourceIndex).releasePeriod(mediaPeriod);
    }

    @Override
    public void releaseSource() {
        for (int i = 0; i < mediaSources.size(); i++) {
            if (!duplicateFlags.get(i)) {
                mediaSources.get(i).releaseSource();
            }
        }
    }

    private void handleSourceInfoRefreshed(int sourceFirstIndex, Timeline sourceTimeline,
                                       Object sourceManifest) {
        // Set the timeline and manifest.
        timelines.put(sourceFirstIndex, sourceTimeline);
        manifests.put(sourceFirstIndex, sourceManifest);

        // Also set the timeline and manifest for any duplicate entries of the same source.
        for (int i = sourceFirstIndex + 1; i < mediaSources.size(); i++) {
            if (mediaSources.get(i).equals(mediaSources.get(sourceFirstIndex))) {
                timelines.put(i, sourceTimeline);
                manifests.put(i, sourceManifest);
            }
        }

        for(int i= 0; i<mediaSources.size(); i++){
            if(timelines.get(i) == null){
                // Don't invoke the listener until all sources have timelines.
                return;
            }
        }

        timeline = new DynamicTimeline(timelines, isRepeatOneAtomic);
        listener.onSourceInfoRefreshed(timeline, new ArrayList(asList(manifests)));
    }

    private static SparseArray<Boolean> buildDuplicateFlags(List<MediaSource> mediaSources) {
        SparseArray<Boolean> duplicateFlags = new SparseArray<Boolean>();
        IdentityHashMap<MediaSource, Void> sources = new IdentityHashMap<>(mediaSources.size());
        for (int i = 0; i < mediaSources.size(); i++) {
            MediaSource source = mediaSources.get(i);
            if (!sources.containsKey(source)) {
                sources.put(source, null);
                duplicateFlags.append(i,false);
            } else {
                duplicateFlags.append(i,true);
            }
        }
        return duplicateFlags;
    }

    /**
     * A {@link Timeline} that is the concatenation of one or more {@link Timeline}s.
     */
    public static final class DynamicTimeline extends AbstractConcatenatedTimeline {

        private final SparseArray<Timeline> timelines;
        private final int[] sourcePeriodOffsets;
        private final int[] sourceWindowOffsets;
        private final boolean isRepeatOneAtomic;

        public DynamicTimeline(SparseArray<Timeline> timelines, boolean isRepeatOneAtomic) {
            super(timelines.size());
            int[] sourcePeriodOffsets = new int[timelines.size()];
            int[] sourceWindowOffsets = new int[timelines.size()];
            long periodCount = 0;
            int windowCount = 0;
            for (int i = 0; i < timelines.size(); i++) {
                Timeline timeline = timelines.get(i);
                periodCount += timeline.getPeriodCount();
                Assertions.checkState(periodCount <= Integer.MAX_VALUE,
                    "ConcatenatingMediaSource children contain too many periods");
                sourcePeriodOffsets[i] = (int) periodCount;
                windowCount += timeline.getWindowCount();
                sourceWindowOffsets[i] = windowCount;
            }
            this.timelines = timelines;
            this.sourcePeriodOffsets = sourcePeriodOffsets;
            this.sourceWindowOffsets = sourceWindowOffsets;
            this.isRepeatOneAtomic = isRepeatOneAtomic;
        }

        @Override
        public int getWindowCount() {
            return sourceWindowOffsets[sourceWindowOffsets.length - 1];
        }

        @Override
        public int getPeriodCount() {
            return sourcePeriodOffsets[sourcePeriodOffsets.length - 1];
        }

        @Override
        public int getNextWindowIndex(int windowIndex, @Player.RepeatMode int repeatMode) {
            if (isRepeatOneAtomic && repeatMode == Player.REPEAT_MODE_ONE) {
                repeatMode = Player.REPEAT_MODE_ALL;
            }
            return super.getNextWindowIndex(windowIndex, repeatMode);
        }

        @Override
        public int getPreviousWindowIndex(int windowIndex, @Player.RepeatMode int repeatMode) {
            if (isRepeatOneAtomic && repeatMode == Player.REPEAT_MODE_ONE) {
                repeatMode = Player.REPEAT_MODE_ALL;
            }
            return super.getPreviousWindowIndex(windowIndex, repeatMode);
        }

        @Override
        public int getChildIndexByPeriodIndex(int periodIndex) {
            return Util.binarySearchFloor(sourcePeriodOffsets, periodIndex, true, false) + 1;
        }

        @Override
        protected int getChildIndexByWindowIndex(int windowIndex) {
            return Util.binarySearchFloor(sourceWindowOffsets, windowIndex, true, false) + 1;
        }

        @Override
        protected int getChildIndexByChildUid(Object childUid) {
            if (!(childUid instanceof Integer)) {
                return C.INDEX_UNSET;
            }
            return (Integer) childUid;
        }

        @Override
        protected Timeline getTimelineByChildIndex(int childIndex) {
            return timelines.get(childIndex);
        }

        @Override
        public int getFirstPeriodIndexByChildIndex(int childIndex) {
            return childIndex == 0 ? 0 : sourcePeriodOffsets[childIndex - 1];
        }

        @Override
        protected int getFirstWindowIndexByChildIndex(int childIndex) {
            return childIndex == 0 ? 0 : sourceWindowOffsets[childIndex - 1];
        }

        @Override
        protected Object getChildUidByChildIndex(int childIndex) {
            return childIndex;
        }

    }

}