Add SegmentDownloader.getAllRepresentationKeys method

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=183656655

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

@@ -104,11 +104,18 @@ public abstract class SegmentDownloader<M, K> implements Downloader {
    * previous selection is cleared. If keys are null or empty, all representations are downloaded.
    */
   public final void selectRepresentations(K[] keys) {
-    this.keys = keys != null ? keys.clone() : null;
+    this.keys = (keys != null && keys.length > 0) ? keys.clone() : null;
     resetCounters();
   }
 
   /**
+   * Returns keys for all representations.
+   *
+   * @see #selectRepresentations(Object[])
+   */
+  public abstract K[] getAllRepresentationKeys() throws IOException;
+
+  /**
    * Initializes the total segments, downloaded segments and downloaded bytes counters for the
    * selected representations.
    *
@@ -221,7 +228,7 @@ public abstract class SegmentDownloader<M, K> implements Downloader {
     if (manifest != null) {
       List<Segment> segments = null;
       try {
-        segments = getAllSegments(offlineDataSource, manifest, true);
+        segments = getSegments(offlineDataSource, manifest, getAllRepresentationKeys(), true);
       } catch (IOException e) {
         // Ignore exceptions. We do our best with what's available offline.
       }
@@ -262,14 +269,6 @@ public abstract class SegmentDownloader<M, K> implements Downloader {
   protected abstract List<Segment> getSegments(DataSource dataSource, M manifest, K[] keys,
       boolean allowIncompleteIndex) throws InterruptedException, IOException;
 
-  /**
-   * Returns a list of all segments.
-   *
-   * @see #getSegments(DataSource, M, Object[], boolean)
-   */
-  protected abstract List<Segment> getAllSegments(DataSource dataSource, M manifest,
-      boolean allowPartialIndex) throws InterruptedException, IOException;
-
   private void resetCounters() {
     totalSegments = C.LENGTH_UNSET;
     downloadedSegments = C.LENGTH_UNSET;
@@ -295,9 +294,10 @@ public abstract class SegmentDownloader<M, K> implements Downloader {
   private synchronized List<Segment> initStatus(boolean offline)
       throws IOException, InterruptedException {
     DataSource dataSource = getDataSource(offline);
-    List<Segment> segments = keys != null && keys.length > 0
-        ? getSegments(dataSource, manifest, keys, offline)
-        : getAllSegments(dataSource, manifest, offline);
+    if (keys == null) {
+      keys = getAllRepresentationKeys();
+    }
+    List<Segment> segments = getSegments(dataSource, manifest, keys, offline);
     CachingCounters cachingCounters = new CachingCounters();
     totalSegments = segments.size();
     downloadedSegments = 0;

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

@@ -75,26 +75,24 @@ public final class DashDownloader extends SegmentDownloader<DashManifest, Repres
   }
 
   @Override
-  public DashManifest getManifest(DataSource dataSource, Uri uri) throws IOException {
-    return DashUtil.loadManifest(dataSource, uri);
-  }
-
-  @Override
-  protected List<Segment> getAllSegments(DataSource dataSource, DashManifest manifest,
-      boolean allowIndexLoadErrors) throws InterruptedException, IOException {
-    ArrayList<Segment> segments = new ArrayList<>();
+  public RepresentationKey[] getAllRepresentationKeys() throws IOException {
+    ArrayList<RepresentationKey> keys = new ArrayList<>();
+    DashManifest manifest = getManifest();
     for (int periodIndex = 0; periodIndex < manifest.getPeriodCount(); periodIndex++) {
       List<AdaptationSet> adaptationSets = manifest.getPeriod(periodIndex).adaptationSets;
       for (int adaptationIndex = 0; adaptationIndex < adaptationSets.size(); adaptationIndex++) {
-        AdaptationSet adaptationSet = adaptationSets.get(adaptationIndex);
-        RepresentationKey[] keys = new RepresentationKey[adaptationSet.representations.size()];
-        for (int i = 0; i < keys.length; i++) {
-          keys[i] = new RepresentationKey(periodIndex, adaptationIndex, i);
+        int representationsCount = adaptationSets.get(adaptationIndex).representations.size();
+        for (int i = 0; i < representationsCount; i++) {
+          keys.add(new RepresentationKey(periodIndex, adaptationIndex, i));
         }
-        segments.addAll(getSegments(dataSource, manifest, keys, allowIndexLoadErrors));
       }
     }
-    return segments;
+    return keys.toArray(new RepresentationKey[keys.size()]);
+  }
+
+  @Override
+  protected DashManifest getManifest(DataSource dataSource, Uri uri) throws IOException {
+    return DashUtil.loadManifest(dataSource, uri);
   }
 
   @Override

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

@@ -36,7 +36,7 @@ import java.util.List;
 /**
  * Helper class to download HLS streams.
  *
- * A subset of renditions can be downloaded by selecting them using {@link
+ * <p>A subset of renditions can be downloaded by selecting them using {@link
  * #selectRepresentations(Object[])}. As key, string form of the rendition's url is used. The urls
  * can be absolute or relative to the master playlist url.
  */
@@ -50,6 +50,16 @@ public final class HlsDownloader extends SegmentDownloader<HlsMasterPlaylist, St
   }
 
   @Override
+  public String[] getAllRepresentationKeys() throws IOException {
+    ArrayList<String> urls = new ArrayList<>();
+    HlsMasterPlaylist manifest = getManifest();
+    extractUrls(manifest.variants, urls);
+    extractUrls(manifest.audios, urls);
+    extractUrls(manifest.subtitles, urls);
+    return urls.toArray(new String[urls.size()]);
+  }
+
+  @Override
   protected HlsMasterPlaylist getManifest(DataSource dataSource, Uri uri) throws IOException {
     HlsPlaylist hlsPlaylist = loadManifest(dataSource, uri);
     if (hlsPlaylist instanceof HlsMasterPlaylist) {
@@ -60,17 +70,6 @@ public final class HlsDownloader extends SegmentDownloader<HlsMasterPlaylist, St
   }
 
   @Override
-  protected List<Segment> getAllSegments(DataSource dataSource, HlsMasterPlaylist manifest,
-      boolean allowIndexLoadErrors) throws InterruptedException, IOException {
-    ArrayList<String> urls = new ArrayList<>();
-    extractUrls(manifest.variants, urls);
-    extractUrls(manifest.audios, urls);
-    extractUrls(manifest.subtitles, urls);
-    return getSegments(dataSource, manifest, urls.toArray(new String[urls.size()]),
-        allowIndexLoadErrors);
-  }
-
-  @Override
   protected List<Segment> getSegments(DataSource dataSource, HlsMasterPlaylist manifest,
       String[] keys, boolean allowIndexLoadErrors) throws InterruptedException, IOException {
     HashSet<Uri> encryptionKeyUris = new HashSet<>();
@@ -104,7 +103,7 @@ public final class HlsDownloader extends SegmentDownloader<HlsMasterPlaylist, St
     return segments;
   }
 
-  private HlsPlaylist loadManifest(DataSource dataSource, Uri uri) throws IOException {
+  private static HlsPlaylist loadManifest(DataSource dataSource, Uri uri) throws IOException {
     DataSpec dataSpec = new DataSpec(uri,
         DataSpec.FLAG_ALLOW_CACHING_UNKNOWN_LENGTH | DataSpec.FLAG_ALLOW_GZIP);
     ParsingLoadable<HlsPlaylist> loadable = new ParsingLoadable<>(dataSource, dataSpec,
@@ -113,9 +112,11 @@ public final class HlsDownloader extends SegmentDownloader<HlsMasterPlaylist, St
     return loadable.getResult();
   }
 
-  private static void addSegment(ArrayList<Segment> segments, HlsMediaPlaylist mediaPlaylist,
-      HlsMediaPlaylist.Segment hlsSegment, HashSet<Uri> encryptionKeyUris)
-      throws IOException, InterruptedException {
+  private static void addSegment(
+      ArrayList<Segment> segments,
+      HlsMediaPlaylist mediaPlaylist,
+      HlsMediaPlaylist.Segment hlsSegment,
+      HashSet<Uri> encryptionKeyUris) {
     long startTimeUs = mediaPlaylist.startTimeUs + hlsSegment.relativeStartTimeUs;
     if (hlsSegment.fullSegmentEncryptionKeyUri != null) {
       Uri keyUri = UriUtil.resolveToUri(mediaPlaylist.baseUri,

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

@@ -33,13 +33,12 @@ import java.util.List;
 /**
  * Helper class to download SmoothStreaming streams.
  *
- * <p>Except {@link #getTotalSegments()}, {@link #getDownloadedSegments()} and
- * {@link #getDownloadedBytes()}, this class isn't thread safe.
+ * <p>Except {@link #getTotalSegments()}, {@link #getDownloadedSegments()} and {@link
+ * #getDownloadedBytes()}, this class isn't thread safe.
  *
  * <p>Example usage:
  *
- * <pre>
- * {@code
+ * <pre>{@code
  * SimpleCache cache = new SimpleCache(downloadFolder, new NoOpCacheEvictor());
  * DefaultHttpDataSourceFactory factory = new DefaultHttpDataSourceFactory("ExoPlayer", null);
  * DownloaderConstructorHelper constructorHelper =
@@ -56,8 +55,8 @@ import java.util.List;
  * });
  * // Access downloaded data using CacheDataSource
  * CacheDataSource cacheDataSource =
- *     new CacheDataSource(cache, factory.createDataSource(), CacheDataSource.FLAG_BLOCK_ON_CACHE);}
- * </pre>
+ *     new CacheDataSource(cache, factory.createDataSource(), CacheDataSource.FLAG_BLOCK_ON_CACHE);
+ * }</pre>
  */
 public final class SsDownloader extends SegmentDownloader<SsManifest, TrackKey> {
 
@@ -69,7 +68,20 @@ public final class SsDownloader extends SegmentDownloader<SsManifest, TrackKey>
   }
 
   @Override
-  public SsManifest getManifest(DataSource dataSource, Uri uri) throws IOException {
+  public TrackKey[] getAllRepresentationKeys() throws IOException {
+    ArrayList<TrackKey> keys = new ArrayList<>();
+    SsManifest manifest = getManifest();
+    for (int i = 0; i < manifest.streamElements.length; i++) {
+      StreamElement streamElement = manifest.streamElements[i];
+      for (int j = 0; j < streamElement.formats.length; j++) {
+        keys.add(new TrackKey(i, j));
+      }
+    }
+    return keys.toArray(new TrackKey[keys.size()]);
+  }
+
+  @Override
+  protected SsManifest getManifest(DataSource dataSource, Uri uri) throws IOException {
     DataSpec dataSpec = new DataSpec(uri,
         DataSpec.FLAG_ALLOW_CACHING_UNKNOWN_LENGTH | DataSpec.FLAG_ALLOW_GZIP);
     ParsingLoadable<SsManifest> loadable = new ParsingLoadable<>(dataSource, dataSpec,
@@ -79,20 +91,6 @@ public final class SsDownloader extends SegmentDownloader<SsManifest, TrackKey>
   }
 
   @Override
-  protected List<Segment> getAllSegments(DataSource dataSource, SsManifest manifest,
-      boolean allowIndexLoadErrors) throws InterruptedException, IOException {
-    ArrayList<Segment> segments = new ArrayList<>();
-    for (int i = 0; i < manifest.streamElements.length; i++) {
-      StreamElement streamElement = manifest.streamElements[i];
-      for (int j = 0; j < streamElement.formats.length; j++) {
-        segments.addAll(getSegments(dataSource, manifest, new TrackKey[] {new TrackKey(i, j)},
-            allowIndexLoadErrors));
-      }
-    }
-    return segments;
-  }
-
-  @Override
   protected List<Segment> getSegments(DataSource dataSource, SsManifest manifest,
       TrackKey[] keys, boolean allowIndexLoadErrors) throws InterruptedException, IOException {
     ArrayList<Segment> segments = new ArrayList<>();