Plumb an ExecutorService into Downloader implementations

Issue: #5978
PiperOrigin-RevId: 307819608

library/core/proguard-rules.txt

@@ -51,15 +51,15 @@
 # Constructors accessed via reflection in DefaultDownloaderFactory
 -dontnote com.google.android.exoplayer2.source.dash.offline.DashDownloader
 -keepclassmembers class com.google.android.exoplayer2.source.dash.offline.DashDownloader {
-  <init>(android.net.Uri, java.util.List, com.google.android.exoplayer2.upstream.cache.CacheDataSource.Factory);
+  <init>(android.net.Uri, java.util.List, com.google.android.exoplayer2.upstream.cache.CacheDataSource.Factory, java.util.concurrent.ExecutorService);
 }
 -dontnote com.google.android.exoplayer2.source.hls.offline.HlsDownloader
 -keepclassmembers class com.google.android.exoplayer2.source.hls.offline.HlsDownloader {
-  <init>(android.net.Uri, java.util.List, com.google.android.exoplayer2.upstream.cache.CacheDataSource.Factory);
+  <init>(android.net.Uri, java.util.List, com.google.android.exoplayer2.upstream.cache.CacheDataSource.Factory, java.util.concurrent.ExecutorService);
 }
 -dontnote com.google.android.exoplayer2.source.smoothstreaming.offline.SsDownloader
 -keepclassmembers class com.google.android.exoplayer2.source.smoothstreaming.offline.SsDownloader {
-  <init>(android.net.Uri, java.util.List, com.google.android.exoplayer2.upstream.cache.CacheDataSource.Factory);
+  <init>(android.net.Uri, java.util.List, com.google.android.exoplayer2.upstream.cache.CacheDataSource.Factory, java.util.concurrent.ExecutorService);
 }
 
 # Constructors accessed via reflection in DefaultMediaSourceFactory and DownloadHelper

library/core/src/main/java/com/google/android/exoplayer2/offline/DefaultDownloaderFactory.java

@@ -20,6 +20,7 @@
 import com.google.android.exoplayer2.upstream.cache.CacheDataSource;
 import java.lang.reflect.Constructor;
 import java.util.List;
+import java.util.concurrent.ExecutorService;
 
 /**
  * Default {@link DownloaderFactory}, supporting creation of progressive, DASH, HLS and
@@ -70,6 +71,7 @@ public class DefaultDownloaderFactory implements DownloaderFactory {
   }
 
   private final CacheDataSource.Factory cacheDataSourceFactory;
+  @Nullable private final ExecutorService executorService;
 
   /**
    * Creates an instance.
@@ -78,15 +80,32 @@ public class DefaultDownloaderFactory implements DownloaderFactory {
    *     downloads will be written.
    */
   public DefaultDownloaderFactory(CacheDataSource.Factory cacheDataSourceFactory) {
+    this(cacheDataSourceFactory, /* executorService= */ null);
+  }
+
+  /**
+   * Creates an instance.
+   *
+   * @param cacheDataSourceFactory A {@link CacheDataSource.Factory} for the cache into which
+   *     downloads will be written.
+   * @param executorService An {@link ExecutorService} used to make requests for media being
+   *     downloaded. Must not be a direct executor, but may be {@code null} if each download should
+   *     make its requests directly on its own thread. Providing an {@link ExecutorService} that
+   *     uses multiple threads will speed up download tasks that can be split into smaller parts for
+   *     parallel execution.
+   */
+  public DefaultDownloaderFactory(
+      CacheDataSource.Factory cacheDataSourceFactory, @Nullable ExecutorService executorService) {
     this.cacheDataSourceFactory = cacheDataSourceFactory;
+    this.executorService = executorService;
   }
 
   @Override
   public Downloader createDownloader(DownloadRequest request) {
     switch (request.type) {
       case DownloadRequest.TYPE_PROGRESSIVE:
         return new ProgressiveDownloader(
-            request.uri, request.customCacheKey, cacheDataSourceFactory);
+            request.uri, request.customCacheKey, cacheDataSourceFactory, executorService);
       case DownloadRequest.TYPE_DASH:
         return createDownloader(request, DASH_DOWNLOADER_CONSTRUCTOR);
       case DownloadRequest.TYPE_HLS:
@@ -98,13 +117,18 @@ public Downloader createDownloader(DownloadRequest request) {
     }
   }
 
+  // Checker framework has no way of knowing whether arguments to newInstance can be null or not,
+  // and so opts to be conservative and assumes they cannot. In this case executorService can be
+  // nullable, so we suppress the warning.
+  @SuppressWarnings("nullness:argument.type.incompatible")
   private Downloader createDownloader(
       DownloadRequest request, @Nullable Constructor<? extends Downloader> constructor) {
     if (constructor == null) {
       throw new IllegalStateException("Module missing for: " + request.type);
     }
     try {
-      return constructor.newInstance(request.uri, request.streamKeys, cacheDataSourceFactory);
+      return constructor.newInstance(
+          request.uri, request.streamKeys, cacheDataSourceFactory, executorService);
     } catch (Exception e) {
       throw new RuntimeException("Failed to instantiate downloader for: " + request.type, e);
     }
@@ -115,7 +139,8 @@ private static Constructor<? extends Downloader> getDownloaderConstructor(Class<
     try {
       return clazz
           .asSubclass(Downloader.class)
-          .getConstructor(Uri.class, List.class, CacheDataSource.Factory.class);
+          .getConstructor(
+              Uri.class, List.class, CacheDataSource.Factory.class, ExecutorService.class);
     } catch (NoSuchMethodException e) {
       // The downloader is present, but the expected constructor is missing.
       throw new RuntimeException("Downloader constructor missing", e);

library/core/src/main/java/com/google/android/exoplayer2/offline/ProgressiveDownloader.java

@@ -23,6 +23,7 @@
 import com.google.android.exoplayer2.upstream.cache.CacheUtil;
 import com.google.android.exoplayer2.util.PriorityTaskManager;
 import java.io.IOException;
+import java.util.concurrent.ExecutorService;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 /** A downloader for progressive media streams. */
@@ -43,6 +44,26 @@ public final class ProgressiveDownloader implements Downloader {
    */
   public ProgressiveDownloader(
       Uri uri, @Nullable String customCacheKey, CacheDataSource.Factory cacheDataSourceFactory) {
+    this(uri, customCacheKey, cacheDataSourceFactory, /* executorService= */ null);
+  }
+
+  /**
+   * @param uri Uri of the data to be downloaded.
+   * @param customCacheKey A custom key that uniquely identifies the original stream. Used for cache
+   *     indexing. May be null.
+   * @param cacheDataSourceFactory A {@link CacheDataSource.Factory} for the cache into which the
+   *     download will be written.
+   * @param executorService An {@link ExecutorService} used to make requests for the media being
+   *     downloaded. Must not be a direct executor, but may be {@code null} if the requests should
+   *     be made directly from the thread that calls {@link #download(ProgressListener)}. In the
+   *     future, providing an {@link ExecutorService} that uses multiple threads may speed up the
+   *     download by allowing parts of it to be executed in parallel.
+   */
+  public ProgressiveDownloader(
+      Uri uri,
+      @Nullable String customCacheKey,
+      CacheDataSource.Factory cacheDataSourceFactory,
+      @Nullable ExecutorService executorService) {
     dataSpec =
         new DataSpec.Builder()
             .setUri(uri)

library/core/src/main/java/com/google/android/exoplayer2/offline/SegmentDownloader.java

@@ -32,6 +32,7 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
+import java.util.concurrent.ExecutorService;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 /**
@@ -77,9 +78,17 @@ public int compareTo(Segment other) {
    *     If empty, all streams are downloaded.
    * @param cacheDataSourceFactory A {@link CacheDataSource.Factory} for the cache into which the
    *     download will be written.
+   * @param executorService An {@link ExecutorService} used to make requests for the media being
+   *     downloaded. Must not be a direct executor, but may be {@code null} if the requests should
+   *     be made directly from the thread that calls {@link #download(ProgressListener)}. Providing
+   *     an {@link ExecutorService} that uses multiple threads will speed up the download by
+   *     allowing parts of it to be executed in parallel.
    */
   public SegmentDownloader(
-      Uri manifestUri, List<StreamKey> streamKeys, CacheDataSource.Factory cacheDataSourceFactory) {
+      Uri manifestUri,
+      List<StreamKey> streamKeys,
+      CacheDataSource.Factory cacheDataSourceFactory,
+      @Nullable ExecutorService executorService) {
     this.manifestDataSpec = getCompressibleDataSpec(manifestUri);
     this.streamKeys = new ArrayList<>(streamKeys);
     this.dataSource = cacheDataSourceFactory.createDataSourceForDownloading();

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/offline/DashDownloader.java

@@ -38,6 +38,7 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.ExecutorService;
 
 /**
  * A downloader for DASH streams.
@@ -73,7 +74,27 @@ public final class DashDownloader extends SegmentDownloader<DashManifest> {
    */
   public DashDownloader(
       Uri manifestUri, List<StreamKey> streamKeys, CacheDataSource.Factory cacheDataSourceFactory) {
-    super(manifestUri, streamKeys, cacheDataSourceFactory);
+    this(manifestUri, streamKeys, cacheDataSourceFactory, /* executorService= */ null);
+  }
+
+  /**
+   * @param manifestUri The {@link Uri} of the manifest to be downloaded.
+   * @param streamKeys Keys defining which representations in the manifest should be selected for
+   *     download. If empty, all representations are downloaded.
+   * @param cacheDataSourceFactory A {@link CacheDataSource.Factory} for the cache into which the
+   *     download will be written.
+   * @param executorService An {@link ExecutorService} used to make requests for the media being
+   *     downloaded. Must not be a direct executor, but may be {@code null} if the requests should
+   *     be made directly from the thread that calls {@link #download(ProgressListener)}. Providing
+   *     an {@link ExecutorService} that uses multiple threads will speed up the download by
+   *     allowing parts of it to be executed in parallel.
+   */
+  public DashDownloader(
+      Uri manifestUri,
+      List<StreamKey> streamKeys,
+      CacheDataSource.Factory cacheDataSourceFactory,
+      @Nullable ExecutorService executorService) {
+    super(manifestUri, streamKeys, cacheDataSourceFactory, executorService);
   }
 
   @Override

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/offline/HlsDownloader.java

@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.source.hls.offline;
 
 import android.net.Uri;
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.offline.SegmentDownloader;
 import com.google.android.exoplayer2.offline.StreamKey;
@@ -32,6 +33,7 @@
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
+import java.util.concurrent.ExecutorService;
 
 /**
  * A downloader for HLS streams.
@@ -67,7 +69,27 @@ public final class HlsDownloader extends SegmentDownloader<HlsPlaylist> {
    */
   public HlsDownloader(
       Uri playlistUri, List<StreamKey> streamKeys, CacheDataSource.Factory cacheDataSourceFactory) {
-    super(playlistUri, streamKeys, cacheDataSourceFactory);
+    this(playlistUri, streamKeys, cacheDataSourceFactory, /* executorService= */ null);
+  }
+
+  /**
+   * @param playlistUri The {@link Uri} of the playlist to be downloaded.
+   * @param streamKeys Keys defining which renditions in the playlist should be selected for
+   *     download. If empty, all renditions are downloaded.
+   * @param cacheDataSourceFactory A {@link CacheDataSource.Factory} for the cache into which the
+   *     download will be written.
+   * @param executorService An {@link ExecutorService} used to make requests for the media being
+   *     downloaded. Must not be a direct executor, but may be {@code null} if the requests should
+   *     be made directly from the thread that calls {@link #download(ProgressListener)}. Providing
+   *     an {@link ExecutorService} that uses multiple threads will speed up the download by
+   *     allowing parts of it to be executed in parallel.
+   */
+  public HlsDownloader(
+      Uri playlistUri,
+      List<StreamKey> streamKeys,
+      CacheDataSource.Factory cacheDataSourceFactory,
+      @Nullable ExecutorService executorService) {
+    super(playlistUri, streamKeys, cacheDataSourceFactory, executorService);
   }
 
   @Override

library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/offline/SsDownloader.java

@@ -16,6 +16,7 @@
 package com.google.android.exoplayer2.source.smoothstreaming.offline;
 
 import android.net.Uri;
+import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.offline.SegmentDownloader;
 import com.google.android.exoplayer2.offline.StreamKey;
@@ -30,6 +31,7 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.ExecutorService;
 
 /**
  * A downloader for SmoothStreaming streams.
@@ -66,7 +68,27 @@ public final class SsDownloader extends SegmentDownloader<SsManifest> {
    */
   public SsDownloader(
       Uri manifestUri, List<StreamKey> streamKeys, CacheDataSource.Factory cacheDataSourceFactory) {
-    super(SsUtil.fixManifestUri(manifestUri), streamKeys, cacheDataSourceFactory);
+    this(manifestUri, streamKeys, cacheDataSourceFactory, /* executorService= */ null);
+  }
+
+  /**
+   * @param manifestUri The {@link Uri} of the manifest to be downloaded.
+   * @param streamKeys Keys defining which streams in the manifest should be selected for download.
+   *     If empty, all streams are downloaded.
+   * @param cacheDataSourceFactory A {@link CacheDataSource.Factory} for the cache into which the
+   *     download will be written.
+   * @param executorService An {@link ExecutorService} used to make requests for the media being
+   *     downloaded. Must not be a direct executor, but may be {@code null} if the requests should
+   *     be made directly from the thread that calls {@link #download(ProgressListener)}. Providing
+   *     an {@link ExecutorService} that uses multiple threads will speed up the download by
+   *     allowing parts of it to be executed in parallel.
+   */
+  public SsDownloader(
+      Uri manifestUri,
+      List<StreamKey> streamKeys,
+      CacheDataSource.Factory cacheDataSourceFactory,
+      @Nullable ExecutorService executorService) {
+    super(SsUtil.fixManifestUri(manifestUri), streamKeys, cacheDataSourceFactory, executorService);
   }
 
   @Override