private void restartFrom(long positionUs) {
pendingResetPositionUs = positionUs;
loadingFinished = false;
if (loader.isLoading()) {
loader.cancelLoading();
} else {
sampleQueue.clear();
mediaChunks.clear();
clearCurrentLoadable();
updateLoadControl();
}
}
private void maybeStartLoading() {
Chunk currentLoadable = currentLoadableHolder.chunk;
if (currentLoadable == null) {
// Nothing to load.
return;
}
currentLoadStartTimeMs = SystemClock.elapsedRealtime();
if (isMediaChunk(currentLoadable)) {
BaseMediaChunk mediaChunk = (BaseMediaChunk) currentLoadable;
mediaChunk.init(sampleQueue);
mediaChunks.add(mediaChunk);
if (isPendingReset()) {
pendingResetPositionUs = NO_RESET_PENDING;
}
notifyLoadStarted(
mediaChunk.dataSpec.length,
mediaChunk.type,
mediaChunk.trigger,
mediaChunk.format,
mediaChunk.startTimeUs,
mediaChunk.endTimeUs);
} else {
notifyLoadStarted(
currentLoadable.dataSpec.length,
currentLoadable.type,
currentLoadable.trigger,
currentLoadable.format,
-1,
-1);
}
loader.startLoading(currentLoadable, this);
}
/**
* Resumes loading.
*
* <p>If the {@link ChunkSource} returns a chunk equivalent to the backed off chunk B, then the
* loading of B will be resumed. In all other cases B will be discarded and the new chunk will be
* loaded.
*/
private void resumeFromBackOff() {
currentLoadableException = null;
Chunk backedOffChunk = currentLoadableHolder.chunk;
if (!isMediaChunk(backedOffChunk)) {
doChunkOperation();
discardUpstreamMediaChunks(currentLoadableHolder.queueSize);
if (currentLoadableHolder.chunk == backedOffChunk) {
// Chunk was unchanged. Resume loading.
loader.startLoading(backedOffChunk, this);
} else {
// Chunk was changed. Notify that the existing load was canceled.
notifyLoadCanceled(backedOffChunk.bytesLoaded());
// Start loading the replacement.
maybeStartLoading();
}
return;
}
if (backedOffChunk == mediaChunks.getFirst()) {
// We're not able to clear the first media chunk, so we have no choice but to continue
// loading it.
loader.startLoading(backedOffChunk, this);
return;
}
// The current loadable is the last media chunk. Remove it before we invoke the chunk source,
// and add it back again afterwards.
BaseMediaChunk removedChunk = mediaChunks.removeLast();
Assertions.checkState(backedOffChunk == removedChunk);
doChunkOperation();
mediaChunks.add(removedChunk);
if (currentLoadableHolder.chunk == backedOffChunk) {
// Chunk was unchanged. Resume loading.
loader.startLoading(backedOffChunk, this);
} else {
// Chunk was changed. Notify that the existing load was canceled.
notifyLoadCanceled(backedOffChunk.bytesLoaded());
// This call will remove and release at least one chunk from the end of mediaChunks. Since
// the current loadable is the last media chunk, it is guaranteed to be removed.
discardUpstreamMediaChunks(currentLoadableHolder.queueSize);
clearCurrentLoadableException();
maybeStartLoading();
}
}
@Override
public void release() {
Assertions.checkState(state != STATE_ENABLED);
if (loader != null) {
loader.release();
loader = null;
}
state = STATE_IDLE;
}
@Override
public void disable(int track) {
Assertions.checkState(state == STATE_ENABLED);
Assertions.checkState(--enabledTrackCount == 0);
state = STATE_PREPARED;
try {
chunkSource.disable(mediaChunks);
} finally {
loadControl.unregister(this);
if (loader.isLoading()) {
loader.cancelLoading();
} else {
sampleQueue.clear();
mediaChunks.clear();
clearCurrentLoadable();
loadControl.trimAllocator();
}
}
}
private void updateLoadControl() {
long now = SystemClock.elapsedRealtime();
long nextLoadPositionUs = getNextLoadPositionUs();
boolean isBackedOff = currentLoadableException != null;
boolean loadingOrBackedOff = loader.isLoading() || isBackedOff;
// If we're not loading or backed off, evaluate the operation if (a) we don't have the next
// chunk yet and we're not finished, or (b) if the last evaluation was over 2000ms ago.
if (!loadingOrBackedOff
&& ((currentLoadableHolder.chunk == null && nextLoadPositionUs != -1)
|| (now - lastPerformedBufferOperation > 2000))) {
// Perform the evaluation.
lastPerformedBufferOperation = now;
doChunkOperation();
boolean chunksDiscarded = discardUpstreamMediaChunks(currentLoadableHolder.queueSize);
// Update the next load position as appropriate.
if (currentLoadableHolder.chunk == null) {
// Set loadPosition to -1 to indicate that we don't have anything to load.
nextLoadPositionUs = -1;
} else if (chunksDiscarded) {
// Chunks were discarded, so we need to re-evaluate the load position.
nextLoadPositionUs = getNextLoadPositionUs();
}
}
// Update the control with our current state, and determine whether we're the next loader.
boolean nextLoader =
loadControl.update(this, downstreamPositionUs, nextLoadPositionUs, loadingOrBackedOff);
if (isBackedOff) {
long elapsedMillis = now - currentLoadableExceptionTimestamp;
if (elapsedMillis >= getRetryDelayMillis(currentLoadableExceptionCount)) {
resumeFromBackOff();
}
return;
}
if (!loader.isLoading() && nextLoader) {
maybeStartLoading();
}
}
