Refresh HlsMediaPlaylist with delivery directives when possible

When refreshing the media playlist, we should try to request via a url with [delivery directives](https://datatracker.ietf.org/doc/html/draft-pantos-hls-rfc8216bis#section-6.2.5). However, when initially loading the media playlist or when the last loading with delivery directives encountered an error, we should not allow using those directives.

PiperOrigin-RevId: 629060177

libraries/exoplayer_hls/src/main/java/androidx/media3/exoplayer/hls/playlist/DefaultHlsPlaylistTracker.java

@@ -225,7 +225,7 @@ public final class DefaultHlsPlaylistTracker
 
   @Override
   public void refreshPlaylist(Uri url) {
-    playlistBundles.get(url).loadPlaylist();
+    playlistBundles.get(url).loadPlaylist(/* allowDeliveryDirectives= */ true);
   }
 
   @Override
@@ -275,7 +275,7 @@ public final class DefaultHlsPlaylistTracker
       // We don't need to load the playlist again. We can use the same result.
       primaryBundle.processLoadedPlaylist((HlsMediaPlaylist) result, loadEventInfo);
     } else {
-      primaryBundle.loadPlaylist();
+      primaryBundle.loadPlaylist(/* allowDeliveryDirectives= */ false);
     }
     loadErrorHandlingPolicy.onLoadTaskConcluded(loadable.loadTaskId);
     eventDispatcher.loadCompleted(loadEventInfo, C.DATA_TYPE_MANIFEST);
@@ -552,8 +552,8 @@ public final class DefaultHlsPlaylistTracker
           || lastSnapshotLoadMs + snapshotValidityDurationMs > currentTimeMs;
     }
 
-    public void loadPlaylist() {
+    public void loadPlaylist(boolean allowDeliveryDirectives) {
-      loadPlaylistInternal(playlistUrl);
+      loadPlaylistInternal(allowDeliveryDirectives ? getMediaPlaylistUriForReload() : playlistUrl);
     }
 
     public void maybeThrowPlaylistRefreshError() throws IOException {
@@ -642,7 +642,7 @@ public final class DefaultHlsPlaylistTracker
           // Service Unavailable (503). In such cases, force a full, non-blocking request (see RFC
           // 8216, section 6.2.5.2 and 6.3.7).
           earliestNextLoadTimeMs = SystemClock.elapsedRealtime();
-          loadPlaylist();
+          loadPlaylist(/* allowDeliveryDirectives= */ false);
           castNonNull(eventDispatcher)
               .loadError(loadEventInfo, loadable.type, error, /* wasCanceled= */ true);
           return Loader.DONT_RETRY;

libraries/exoplayer_hls/src/test/java/androidx/media3/exoplayer/hls/playlist/DefaultHlsPlaylistTrackerTest.java

@@ -78,6 +78,9 @@ public class DefaultHlsPlaylistTrackerTest {
   private static final String
       SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY_FULL_SEGMENT_NEXT =
           "media/m3u8/live_low_latency_media_can_block_reload_low_latency_full_segment_next";
+  private static final String
+      SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY_FULL_SEGMENT_NEXT2 =
+          "media/m3u8/live_low_latency_media_can_block_reload_low_latency_full_segment_next2";
   private static final String
       SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY_FULL_SEGMENT_PRELOAD =
           "media/m3u8/live_low_latency_media_can_block_reload_low_latency_full_segment_preload";
@@ -446,6 +449,80 @@ public class DefaultHlsPlaylistTrackerTest {
     assertThat(mediaPlaylists.get(1).trailingParts).hasSize(2);
   }
 
+  @Test
+  public void
+      start_refreshPlaylistWithAllowingDeliveryDirectives_requestWithCorrectDeliveryDirectives()
+          throws Exception {
+    List<HttpUrl> httpUrls =
+        enqueueWebServerResponses(
+            new String[] {
+              "/multivariant.m3u8",
+              "/media0/playlist.m3u8",
+              "/media0/playlist.m3u8?_HLS_msn=14&_HLS_part=0",
+              "/media0/playlist.m3u8?_HLS_msn=14&_HLS_part=1"
+            },
+            getMockResponse(SAMPLE_M3U8_LIVE_MULTIVARIANT),
+            getMockResponse(SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY_FULL_SEGMENT),
+            getMockResponse(SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY_FULL_SEGMENT_NEXT),
+            getMockResponse(
+                SAMPLE_M3U8_LIVE_MEDIA_CAN_BLOCK_RELOAD_LOW_LATENCY_FULL_SEGMENT_NEXT2));
+
+    DefaultHlsPlaylistTracker defaultHlsPlaylistTracker =
+        new DefaultHlsPlaylistTracker(
+            dataType -> new DefaultHttpDataSource.Factory().createDataSource(),
+            new DefaultLoadErrorHandlingPolicy(),
+            new DefaultHlsPlaylistParserFactory());
+    List<HlsMediaPlaylist> mediaPlaylists = new ArrayList<>();
+    AtomicInteger playlistCounter = new AtomicInteger();
+    AtomicReference<TimeoutException> playlistRefreshExceptionRef = new AtomicReference<>();
+    defaultHlsPlaylistTracker.addListener(
+        new HlsPlaylistTracker.PlaylistEventListener() {
+          @Override
+          public void onPlaylistChanged() {
+            // Upon the first call of onPlaylistChanged(), we call refreshPlaylist(Uri) on the
+            // same url.
+            defaultHlsPlaylistTracker.refreshPlaylist(
+                defaultHlsPlaylistTracker.getMultivariantPlaylist().mediaPlaylistUrls.get(0));
+            try {
+              // Make sure that playlist reload triggered by refreshPlaylist(Uri) call comes before
+              // the one triggered by the regular scheduling, to ensure the playlists to be
+              // verified are in the expected order.
+              RobolectricUtil.runMainLooperUntil(() -> playlistCounter.get() >= 2);
+            } catch (TimeoutException e) {
+              playlistRefreshExceptionRef.set(e);
+            }
+          }
+
+          @Override
+          public boolean onPlaylistError(
+              Uri url, LoadErrorHandlingPolicy.LoadErrorInfo loadErrorInfo, boolean forceRetry) {
+            return false;
+          }
+        });
+
+    defaultHlsPlaylistTracker.start(
+        Uri.parse(mockWebServer.url("/multivariant.m3u8").toString()),
+        new MediaSourceEventListener.EventDispatcher(),
+        mediaPlaylist -> {
+          mediaPlaylists.add(mediaPlaylist);
+          playlistCounter.addAndGet(1);
+        });
+    RobolectricUtil.runMainLooperUntil(() -> playlistCounter.get() >= 3);
+    defaultHlsPlaylistTracker.stop();
+
+    assertThat(playlistRefreshExceptionRef.get()).isNull();
+    assertRequestUrlsCalled(httpUrls);
+    assertThat(mediaPlaylists.get(0).mediaSequence).isEqualTo(10);
+    assertThat(mediaPlaylists.get(0).segments).hasSize(4);
+    assertThat(mediaPlaylists.get(0).trailingParts).isEmpty();
+    assertThat(mediaPlaylists.get(1).mediaSequence).isEqualTo(10);
+    assertThat(mediaPlaylists.get(1).segments).hasSize(4);
+    assertThat(mediaPlaylists.get(1).trailingParts).hasSize(1);
+    assertThat(mediaPlaylists.get(2).mediaSequence).isEqualTo(10);
+    assertThat(mediaPlaylists.get(2).segments).hasSize(4);
+    assertThat(mediaPlaylists.get(2).trailingParts).hasSize(2);
+  }
+
   @Test
   public void start_httpBadRequest_forcesFullNonBlockingPlaylistRequest()
       throws IOException, TimeoutException, InterruptedException {

libraries/test_data/src/test/assets/media/m3u8/live_low_latency_media_can_block_reload_low_latency_full_segment_next2

@@ -0,0 +1,20 @@
+#EXTM3U
+#EXT-X-SERVER-CONTROL:CAN-BLOCK-RELOAD=YES
+#EXT-X-TARGETDURATION:4
+#EXT-X-PART-INF:PART-TARGET=1.000000
+#EXT-X-VERSION:3
+#EXT-X-MEDIA-SEQUENCE:10
+#EXTINF:4.00000,
+fileSequence10.ts
+#EXTINF:4.00000,
+fileSequence11.ts
+#EXTINF:4.00000,
+fileSequence12.ts
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.0.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.1.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.2.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence13.3.ts"
+#EXTINF:4.00000,
+fileSequence13.ts
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence14.0.ts"
+#EXT-X-PART:DURATION=1.00000,URI="fileSequence14.1.ts"