Fix bug where enabling CMCD for HLS live streams causes error

Determine `nextMediaSequence` and `nextPartIndex` based on the last `SegmentBaseHolder` instance, as it can update `mediaSequence` and `partIndex` depending on whether the HLS playlist has trailing parts or not.

Issue: #1395
PiperOrigin-RevId: 642961141

RELEASENOTES.md

@@ -133,6 +133,9 @@ This release includes the following changes since the
         schedule its work loop as renderers can make progress.
     *   Use data class for `LoadControl` methods instead of individual
         parameters.
+    *   Fix bug where enabling CMCD for HLS live streams causes
+        `ArrayIndexOutOfBoundsException`
+        ([#1395](https://github.com/androidx/media/issues/1395)).
 *   Transformer:
     *   Work around a decoder bug where the number of audio channels was capped
         at stereo when handling PCM input.

libraries/exoplayer_hls/src/main/java/androidx/media3/exoplayer/hls/HlsChunkSource.java

@@ -521,13 +521,16 @@ public void getNextChunk(
                       ? CmcdData.Factory.OBJECT_TYPE_MUXED_AUDIO_AND_VIDEO
                       : CmcdData.Factory.getObjectType(trackSelection));
 
-      long nextChunkMediaSequence =
-          partIndex == C.INDEX_UNSET
-              ? (chunkMediaSequence == C.INDEX_UNSET ? C.INDEX_UNSET : chunkMediaSequence + 1)
-              : chunkMediaSequence;
-      int nextPartIndex = partIndex == C.INDEX_UNSET ? C.INDEX_UNSET : partIndex + 1;
+      long nextMediaSequence =
+          segmentBaseHolder.partIndex == C.INDEX_UNSET
+              ? segmentBaseHolder.mediaSequence + 1
+              : segmentBaseHolder.mediaSequence;
+      int nextPartIndex =
+          segmentBaseHolder.partIndex == C.INDEX_UNSET
+              ? C.INDEX_UNSET
+              : segmentBaseHolder.partIndex + 1;
       SegmentBaseHolder nextSegmentBaseHolder =
-          getNextSegmentHolder(playlist, nextChunkMediaSequence, nextPartIndex);
+          getNextSegmentHolder(playlist, nextMediaSequence, nextPartIndex);
       if (nextSegmentBaseHolder != null) {
         Uri uri = UriUtil.resolveToUri(playlist.baseUri, segmentBaseHolder.segmentBase.url);
         Uri nextUri = UriUtil.resolveToUri(playlist.baseUri, nextSegmentBaseHolder.segmentBase.url);

libraries/exoplayer_hls/src/test/java/androidx/media3/exoplayer/hls/HlsChunkSourceTest.java

@@ -58,6 +58,10 @@ public class HlsChunkSourceTest {
   private static final String PLAYLIST = "media/m3u8/media_playlist";
   private static final String PLAYLIST_INDEPENDENT_SEGMENTS =
       "media/m3u8/media_playlist_independent_segments";
+  private static final String PLAYLIST_LIVE_LOW_LATENCY_SEGEMENTS_ONLY =
+      "media/m3u8/live_low_latency_segments_only";
+  private static final String PLAYLIST_LIVE_LOW_LATENCY_SEGEMENTS_AND_PARTS =
+      "media/m3u8/live_low_latency_segments_and_parts";
   private static final String PLAYLIST_EMPTY = "media/m3u8/media_playlist_empty";
   private static final Uri PLAYLIST_URI = Uri.parse("http://example.com/");
   private static final long PLAYLIST_START_PERIOD_OFFSET_US = 8_000_000L;
@@ -305,6 +309,96 @@ public void getNextChunk_chunkSourceWithDefaultCmcdConfiguration_setsCmcdHttpReq
     assertThat(output.chunk.dataSpec.httpRequestHeaders).doesNotContainKey("CMCD-Status");
   }
 
+  @Test
+  public void getNextChunk_forLivePlaylistWithSegmentsOnly_setsCorrectNextObjectRequest()
+      throws IOException {
+    // The live playlist contains 6 segments, each 4 seconds long. With a playlist start offset of 8
+    // seconds, the total media time is 8 + 6*4 = 32 seconds.
+    InputStream inputStream =
+        TestUtil.getInputStream(
+            ApplicationProvider.getApplicationContext(), PLAYLIST_LIVE_LOW_LATENCY_SEGEMENTS_ONLY);
+    HlsMediaPlaylist playlist =
+        (HlsMediaPlaylist) new HlsPlaylistParser().parse(PLAYLIST_URI, inputStream);
+    when(mockPlaylistTracker.getPlaylistSnapshot(eq(PLAYLIST_URI), anyBoolean()))
+        .thenReturn(playlist);
+    CmcdConfiguration.Factory cmcdConfigurationFactory = CmcdConfiguration.Factory.DEFAULT;
+    MediaItem mediaItem = new MediaItem.Builder().setMediaId("mediaId").build();
+    CmcdConfiguration cmcdConfiguration =
+        cmcdConfigurationFactory.createCmcdConfiguration(mediaItem);
+    HlsChunkSource testChunkSource = createHlsChunkSource(cmcdConfiguration);
+    HlsChunkSource.HlsChunkHolder output = new HlsChunkSource.HlsChunkHolder();
+
+    // A request to fetch the chunk at 27 seconds should retrieve the second-to-last segment.
+    testChunkSource.getNextChunk(
+        new LoadingInfo.Builder().setPlaybackPositionUs(27_000_000).setPlaybackSpeed(1.0f).build(),
+        /* loadPositionUs= */ 27_000_000,
+        /* queue= */ ImmutableList.of(),
+        /* allowEndOfStream= */ true,
+        output);
+
+    // The `nor` key should point to the last segment, which is `FileSequence15.ts`.
+    assertThat(output.chunk.dataSpec.httpRequestHeaders)
+        .containsEntry("CMCD-Request", "bl=0,dl=0,nor=\"..%2FfileSequence15.ts\",nrr=\"0-\",su");
+
+    // A request to fetch the chunk at 31 seconds should retrieve the last segment.
+    testChunkSource.getNextChunk(
+        new LoadingInfo.Builder().setPlaybackPositionUs(31_000_000).setPlaybackSpeed(1.0f).build(),
+        /* loadPositionUs= */ 31_000_000,
+        /* queue= */ ImmutableList.of(),
+        /* allowEndOfStream= */ true,
+        output);
+
+    // Since there are no next segments left, the `nor` key should be absent.
+    assertThat(output.chunk.dataSpec.httpRequestHeaders)
+        .containsEntry("CMCD-Request", "bl=0,dl=0,su");
+  }
+
+  @Test
+  public void getNextChunk_forLivePlaylistWithSegmentsAndParts_setsCorrectNextObjectRequest()
+      throws IOException {
+    // The live playlist contains 6 segments, each 4 seconds long, and two trailing parts of 1
+    // second each. With a playlist start offset of 8 seconds, the total media time is 8 + 6*4 + 2*1
+    // = 34 seconds.
+    InputStream inputStream =
+        TestUtil.getInputStream(
+            ApplicationProvider.getApplicationContext(),
+            PLAYLIST_LIVE_LOW_LATENCY_SEGEMENTS_AND_PARTS);
+    HlsMediaPlaylist playlist =
+        (HlsMediaPlaylist) new HlsPlaylistParser().parse(PLAYLIST_URI, inputStream);
+    when(mockPlaylistTracker.getPlaylistSnapshot(eq(PLAYLIST_URI), anyBoolean()))
+        .thenReturn(playlist);
+    CmcdConfiguration.Factory cmcdConfigurationFactory = CmcdConfiguration.Factory.DEFAULT;
+    MediaItem mediaItem = new MediaItem.Builder().setMediaId("mediaId").build();
+    CmcdConfiguration cmcdConfiguration =
+        cmcdConfigurationFactory.createCmcdConfiguration(mediaItem);
+    HlsChunkSource testChunkSource = createHlsChunkSource(cmcdConfiguration);
+    HlsChunkSource.HlsChunkHolder output = new HlsChunkSource.HlsChunkHolder();
+
+    // A request to fetch the chunk at 31 seconds should retrieve the last segment.
+    testChunkSource.getNextChunk(
+        new LoadingInfo.Builder().setPlaybackPositionUs(31_000_000).setPlaybackSpeed(1.0f).build(),
+        /* loadPositionUs= */ 31_000_000,
+        /* queue= */ ImmutableList.of(),
+        /* allowEndOfStream= */ true,
+        output);
+
+    // The `nor` key should point to the first trailing part, which is `FileSequence16.0.ts`.
+    assertThat(output.chunk.dataSpec.httpRequestHeaders)
+        .containsEntry("CMCD-Request", "bl=0,dl=0,nor=\"..%2FfileSequence16.0.ts\",nrr=\"0-\",su");
+
+    // A request to fetch the chunk at 34 seconds should retrieve the first trailing part.
+    testChunkSource.getNextChunk(
+        new LoadingInfo.Builder().setPlaybackPositionUs(34_000_000).setPlaybackSpeed(1.0f).build(),
+        /* loadPositionUs= */ 34_000_000,
+        /* queue= */ ImmutableList.of(),
+        /* allowEndOfStream= */ true,
+        output);
+
+    // The `nor` key should point to the second trailing part, which is `FileSequence16.1.ts`.
+    assertThat(output.chunk.dataSpec.httpRequestHeaders)
+        .containsEntry("CMCD-Request", "bl=0,dl=0,nor=\"..%2FfileSequence16.1.ts\",nrr=\"0-\",su");
+  }
+
   @Test
   public void getNextChunk_chunkSourceWithCustomCmcdConfiguration_setsCmcdHttpRequestHeaders() {
     CmcdConfiguration.Factory cmcdConfigurationFactory =