ProgressiveDownloader.java
/*
* 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 androidx.media3.exoplayer.offline;
import static androidx.media3.common.util.Assertions.checkNotNull;
import androidx.annotation.Nullable;
import androidx.media3.common.C;
import androidx.media3.common.MediaItem;
import androidx.media3.common.PriorityTaskManager;
import androidx.media3.common.PriorityTaskManager.PriorityTooLowException;
import androidx.media3.common.util.Assertions;
import androidx.media3.common.util.RunnableFutureTask;
import androidx.media3.common.util.UnstableApi;
import androidx.media3.common.util.Util;
import androidx.media3.datasource.DataSpec;
import androidx.media3.datasource.cache.CacheDataSource;
import androidx.media3.datasource.cache.CacheWriter;
import java.io.IOException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
/** A downloader for progressive media streams. */
@UnstableApi
public final class ProgressiveDownloader implements Downloader {
private final Executor executor;
private final DataSpec dataSpec;
private final CacheDataSource dataSource;
private final CacheWriter cacheWriter;
@Nullable private final PriorityTaskManager priorityTaskManager;
@Nullable private ProgressListener progressListener;
private volatile @MonotonicNonNull RunnableFutureTask<Void, IOException> downloadRunnable;
private volatile boolean isCanceled;
/**
* Creates a new instance.
*
* @param mediaItem The media item with a uri to the stream to be downloaded.
* @param cacheDataSourceFactory A {@link CacheDataSource.Factory} for the cache into which the
* download will be written.
*/
public ProgressiveDownloader(
MediaItem mediaItem, CacheDataSource.Factory cacheDataSourceFactory) {
this(mediaItem, cacheDataSourceFactory, Runnable::run);
}
/**
* Creates a new instance.
*
* @param mediaItem The media item with a uri to the stream to be downloaded.
* @param cacheDataSourceFactory A {@link CacheDataSource.Factory} for the cache into which the
* download will be written.
* @param executor An {@link Executor} used to make requests for the media being downloaded. In
* the future, providing an {@link Executor} that uses multiple threads may speed up the
* download by allowing parts of it to be executed in parallel.
*/
public ProgressiveDownloader(
MediaItem mediaItem, CacheDataSource.Factory cacheDataSourceFactory, Executor executor) {
this.executor = Assertions.checkNotNull(executor);
Assertions.checkNotNull(mediaItem.localConfiguration);
dataSpec =
new DataSpec.Builder()
.setUri(mediaItem.localConfiguration.uri)
.setKey(mediaItem.localConfiguration.customCacheKey)
.setFlags(DataSpec.FLAG_ALLOW_CACHE_FRAGMENTATION)
.build();
dataSource = cacheDataSourceFactory.createDataSourceForDownloading();
@SuppressWarnings("nullness:methodref.receiver.bound")
CacheWriter.ProgressListener progressListener = this::onProgress;
cacheWriter =
new CacheWriter(dataSource, dataSpec, /* temporaryBuffer= */ null, progressListener);
priorityTaskManager = cacheDataSourceFactory.getUpstreamPriorityTaskManager();
}
@Override
public void download(@Nullable ProgressListener progressListener)
throws IOException, InterruptedException {
this.progressListener = progressListener;
if (priorityTaskManager != null) {
priorityTaskManager.add(C.PRIORITY_DOWNLOAD);
}
try {
boolean finished = false;
while (!finished && !isCanceled) {
// Recreate downloadRunnable on each loop iteration to avoid rethrowing a previous error.
downloadRunnable =
new RunnableFutureTask<Void, IOException>() {
@Override
protected Void doWork() throws IOException {
cacheWriter.cache();
return null;
}
@Override
protected void cancelWork() {
cacheWriter.cancel();
}
};
if (priorityTaskManager != null) {
priorityTaskManager.proceed(C.PRIORITY_DOWNLOAD);
}
executor.execute(downloadRunnable);
try {
downloadRunnable.get();
finished = true;
} catch (ExecutionException e) {
Throwable cause = Assertions.checkNotNull(e.getCause());
if (cause instanceof PriorityTooLowException) {
// The next loop iteration will block until the task is able to proceed.
} else if (cause instanceof IOException) {
throw (IOException) cause;
} else {
// The cause must be an uncaught Throwable type.
Util.sneakyThrow(cause);
}
}
}
} finally {
// If the main download thread was interrupted as part of cancelation, then it's possible that
// the runnable is still doing work. We need to wait until it's finished before returning.
checkNotNull(downloadRunnable).blockUntilFinished();
if (priorityTaskManager != null) {
priorityTaskManager.remove(C.PRIORITY_DOWNLOAD);
}
}
}
@Override
public void cancel() {
isCanceled = true;
RunnableFutureTask<Void, IOException> downloadRunnable = this.downloadRunnable;
if (downloadRunnable != null) {
downloadRunnable.cancel(/* interruptIfRunning= */ true);
}
}
@Override
public void remove() {
dataSource.getCache().removeResource(dataSource.getCacheKeyFactory().buildCacheKey(dataSpec));
}
private void onProgress(long contentLength, long bytesCached, long newBytesCached) {
if (progressListener == null) {
return;
}
float percentDownloaded =
contentLength == C.LENGTH_UNSET || contentLength == 0
? C.PERCENTAGE_UNSET
: ((bytesCached * 100f) / contentLength);
progressListener.onProgress(contentLength, bytesCached, percentDownloaded);
}
}