Rework HlsPlaylist attribute inheritance

The reason for the change is that variable substititution requires
master playlist variable definitions at the moment of parsing.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=208997963

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

@@ -36,6 +36,7 @@ import com.google.android.exoplayer2.source.hls.playlist.DefaultHlsPlaylistTrack
 import com.google.android.exoplayer2.source.hls.playlist.HlsMediaPlaylist;
 import com.google.android.exoplayer2.source.hls.playlist.HlsPlaylist;
 import com.google.android.exoplayer2.source.hls.playlist.HlsPlaylistParser;
+import com.google.android.exoplayer2.source.hls.playlist.HlsPlaylistParserFactory;
 import com.google.android.exoplayer2.source.hls.playlist.HlsPlaylistTracker;
 import com.google.android.exoplayer2.upstream.Allocator;
 import com.google.android.exoplayer2.upstream.DataSource;
@@ -171,7 +172,11 @@ public final class HlsMediaSource extends BaseMediaSource
      * @param playlistParser A {@link ParsingLoadable.Parser} for HLS playlists.
      * @return This factory, for convenience.
      * @throws IllegalStateException If one of the {@code create} methods has already been called.
+     * @deprecated Use {@link #setPlaylistTracker(HlsPlaylistTracker)} instead. Using this method
+     *     prevents support for attributes that are carried over from the master playlist to the
+     *     media playlists.
      */
+    @Deprecated
     public Factory setPlaylistParser(ParsingLoadable.Parser<HlsPlaylist> playlistParser) {
       Assertions.checkState(!isCreateCalled);
       Assertions.checkState(playlistTracker == null, "A playlist tracker has already been set.");
@@ -239,11 +244,15 @@ public final class HlsMediaSource extends BaseMediaSource
     public HlsMediaSource createMediaSource(Uri playlistUri) {
       isCreateCalled = true;
       if (playlistTracker == null) {
+        if (playlistParser == null) {
           playlistTracker =
               new DefaultHlsPlaylistTracker(
-                hlsDataSourceFactory,
+                  hlsDataSourceFactory, loadErrorHandlingPolicy, HlsPlaylistParserFactory.DEFAULT);
-                loadErrorHandlingPolicy,
+        } else {
-                playlistParser != null ? playlistParser : new HlsPlaylistParser());
+          playlistTracker =
+              new DefaultHlsPlaylistTracker(
+                  hlsDataSourceFactory, loadErrorHandlingPolicy, playlistParser);
+        }
       }
       return new HlsMediaSource(
           playlistUri,

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/DefaultHlsPlaylistTracker.java

@@ -18,6 +18,7 @@ package com.google.android.exoplayer2.source.hls.playlist;
 import android.net.Uri;
 import android.os.Handler;
 import android.os.SystemClock;
+import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ParserException;
 import com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
@@ -47,18 +48,19 @@ public final class DefaultHlsPlaylistTracker
   private static final double PLAYLIST_STUCK_TARGET_DURATION_COEFFICIENT = 3.5;
 
   private final HlsDataSourceFactory dataSourceFactory;
-  private final ParsingLoadable.Parser<HlsPlaylist> playlistParser;
+  private final HlsPlaylistParserFactory playlistParserFactory;
   private final LoadErrorHandlingPolicy loadErrorHandlingPolicy;
   private final IdentityHashMap<HlsUrl, MediaPlaylistBundle> playlistBundles;
   private final List<PlaylistEventListener> listeners;
 
-  private EventDispatcher eventDispatcher;
+  private @Nullable ParsingLoadable.Parser<HlsPlaylist> mediaPlaylistParser;
-  private Loader initialPlaylistLoader;
+  private @Nullable EventDispatcher eventDispatcher;
-  private Handler playlistRefreshHandler;
+  private @Nullable Loader initialPlaylistLoader;
-  private PrimaryPlaylistListener primaryPlaylistListener;
+  private @Nullable Handler playlistRefreshHandler;
-  private HlsMasterPlaylist masterPlaylist;
+  private @Nullable PrimaryPlaylistListener primaryPlaylistListener;
-  private HlsUrl primaryHlsUrl;
+  private @Nullable HlsMasterPlaylist masterPlaylist;
-  private HlsMediaPlaylist primaryUrlSnapshot;
+  private @Nullable HlsUrl primaryHlsUrl;
+  private @Nullable HlsMediaPlaylist primaryUrlSnapshot;
   private boolean isLive;
   private long initialStartTimeUs;
 
@@ -66,13 +68,30 @@ public final class DefaultHlsPlaylistTracker
    * @param dataSourceFactory A factory for {@link DataSource} instances.
    * @param loadErrorHandlingPolicy The {@link LoadErrorHandlingPolicy}.
    * @param playlistParser A {@link ParsingLoadable.Parser} for HLS playlists.
+   * @deprecated Use {@link #DefaultHlsPlaylistTracker(HlsDataSourceFactory,
+   *     LoadErrorHandlingPolicy, HlsPlaylistParserFactory)} instead. Using this constructor
+   *     prevents support for attributes that are carried over from the master playlist to the media
+   *     playlists.
    */
+  @Deprecated
   public DefaultHlsPlaylistTracker(
       HlsDataSourceFactory dataSourceFactory,
       LoadErrorHandlingPolicy loadErrorHandlingPolicy,
       ParsingLoadable.Parser<HlsPlaylist> playlistParser) {
+    this(dataSourceFactory, loadErrorHandlingPolicy, createFixedFactory(playlistParser));
+  }
+
+  /**
+   * @param dataSourceFactory A factory for {@link DataSource} instances.
+   * @param loadErrorHandlingPolicy The {@link LoadErrorHandlingPolicy}.
+   * @param playlistParserFactory An {@link HlsPlaylistParserFactory}.
+   */
+  public DefaultHlsPlaylistTracker(
+      HlsDataSourceFactory dataSourceFactory,
+      LoadErrorHandlingPolicy loadErrorHandlingPolicy,
+      HlsPlaylistParserFactory playlistParserFactory) {
     this.dataSourceFactory = dataSourceFactory;
-    this.playlistParser = playlistParser;
+    this.playlistParserFactory = playlistParserFactory;
     this.loadErrorHandlingPolicy = loadErrorHandlingPolicy;
     listeners = new ArrayList<>();
     playlistBundles = new IdentityHashMap<>();
@@ -94,7 +113,7 @@ public final class DefaultHlsPlaylistTracker
             dataSourceFactory.createDataSource(C.DATA_TYPE_MANIFEST),
             initialPlaylistUri,
             C.DATA_TYPE_MANIFEST,
-            playlistParser);
+            playlistParserFactory.createPlaylistParser());
     Assertions.checkState(initialPlaylistLoader == null);
     initialPlaylistLoader = new Loader("DefaultHlsPlaylistTracker:MasterPlaylist");
     long elapsedRealtime =
@@ -198,6 +217,7 @@ public final class DefaultHlsPlaylistTracker
       masterPlaylist = (HlsMasterPlaylist) result;
     }
     this.masterPlaylist = masterPlaylist;
+    mediaPlaylistParser = playlistParserFactory.createPlaylistParser(masterPlaylist);
     primaryHlsUrl = masterPlaylist.variants.get(0);
     ArrayList<HlsUrl> urls = new ArrayList<>();
     urls.addAll(masterPlaylist.variants);
@@ -420,7 +440,7 @@ public final class DefaultHlsPlaylistTracker
               dataSourceFactory.createDataSource(C.DATA_TYPE_MANIFEST),
               UriUtil.resolveToUri(masterPlaylist.baseUri, playlistUrl.url),
               C.DATA_TYPE_MANIFEST,
-              playlistParser);
+              mediaPlaylistParser);
     }
 
     public HlsMediaPlaylist getPlaylistSnapshot() {
@@ -569,9 +589,6 @@ public final class DefaultHlsPlaylistTracker
     }
 
     private void processLoadedPlaylist(HlsMediaPlaylist loadedPlaylist, long loadDurationMs) {
-      // Update the loaded playlist with any inheritable information from the master playlist.
-      loadedPlaylist = loadedPlaylist.copyWithMasterPlaylistInfo(masterPlaylist);
-
       HlsMediaPlaylist oldPlaylist = playlistSnapshot;
       long currentTimeMs = SystemClock.elapsedRealtime();
       lastSnapshotLoadMs = currentTimeMs;
@@ -630,4 +647,26 @@ public final class DefaultHlsPlaylistTracker
       return primaryHlsUrl == playlistUrl && !maybeSelectNewPrimaryUrl();
     }
   }
+
+  /**
+   * Creates a factory which always returns the given playlist parser.
+   *
+   * @param playlistParser The parser to return.
+   * @return A factory which always returns the given playlist parser.
+   */
+  private static HlsPlaylistParserFactory createFixedFactory(
+      ParsingLoadable.Parser<HlsPlaylist> playlistParser) {
+    return new HlsPlaylistParserFactory() {
+      @Override
+      public ParsingLoadable.Parser<HlsPlaylist> createPlaylistParser() {
+        return playlistParser;
+      }
+
+      @Override
+      public ParsingLoadable.Parser<HlsPlaylist> createPlaylistParser(
+          HlsMasterPlaylist masterPlaylist) {
+        return playlistParser;
+      }
+    };
+  }
 }

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsMasterPlaylist.java

@@ -25,6 +25,18 @@ import java.util.List;
 /** Represents an HLS master playlist. */
 public final class HlsMasterPlaylist extends HlsPlaylist {
 
+  /** Represents an empty master playlist, from which no attributes can be inherited. */
+  public static final HlsMasterPlaylist EMPTY =
+      new HlsMasterPlaylist(
+          /* baseUri= */ "",
+          /* tags= */ Collections.emptyList(),
+          /* variants= */ Collections.emptyList(),
+          /* audios= */ Collections.emptyList(),
+          /* subtitles= */ Collections.emptyList(),
+          /* muxedAudioFormat= */ null,
+          /* muxedCaptionFormats= */ Collections.emptyList(),
+          /* hasIndependentSegments= */ false);
+
   public static final int GROUP_INDEX_VARIANT = 0;
   public static final int GROUP_INDEX_AUDIO = 1;
   public static final int GROUP_INDEX_SUBTITLE = 2;

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylist.java

@@ -336,40 +336,6 @@ public final class HlsMediaPlaylist extends HlsPlaylist {
         segments);
   }
 
-  /**
-   * Returns a playlist identical to this one, except for adding any inheritable attributes from the
-   * provided {@link HlsMasterPlaylist}.
-   *
-   * <p>The inheritable attributes are:
-   *
-   * <ul>
-   *   <li>{@link #hasIndependentSegments}.
-   * </ul>
-   *
-   * @return An identical playlist including the inheritable attributes from {@code masterPlaylist}.
-   */
-  public HlsMediaPlaylist copyWithMasterPlaylistInfo(HlsMasterPlaylist masterPlaylist) {
-    if (hasIndependentSegments || !masterPlaylist.hasIndependentSegments) {
-      return this;
-    }
-    return new HlsMediaPlaylist(
-        playlistType,
-        baseUri,
-        tags,
-        startOffsetUs,
-        startTimeUs,
-        hasDiscontinuitySequence,
-        discontinuitySequence,
-        mediaSequence,
-        version,
-        targetDurationUs,
-        hasIndependentSegments || masterPlaylist.hasIndependentSegments,
-        hasEndTag,
-        hasProgramDateTime,
-        protectionSchemes,
-        segments);
-  }
-
   /**
    * Returns a playlist identical to this one except that an end tag is added. If an end tag is
    * already present then the playlist will return itself.

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsPlaylistParser.java

@@ -148,6 +148,26 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
   private static final Pattern REGEX_DEFAULT = compileBooleanAttrPattern("DEFAULT");
   private static final Pattern REGEX_FORCED = compileBooleanAttrPattern("FORCED");
 
+  private final HlsMasterPlaylist masterPlaylist;
+
+  /**
+   * Creates an instance where media playlists are parsed without inheriting attributes from a
+   * master playlist.
+   */
+  public HlsPlaylistParser() {
+    this(HlsMasterPlaylist.EMPTY);
+  }
+
+  /**
+   * Creates an instance where parsed media playlists inherit attributes from the given master
+   * playlist.
+   *
+   * @param masterPlaylist The master playlist from which media playlists will inherit attributes.
+   */
+  public HlsPlaylistParser(HlsMasterPlaylist masterPlaylist) {
+    this.masterPlaylist = masterPlaylist;
+  }
+
   @Override
   public HlsPlaylist parse(Uri uri, InputStream inputStream) throws IOException {
     BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
@@ -174,7 +194,8 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
             || line.equals(TAG_DISCONTINUITY_SEQUENCE)
             || line.equals(TAG_ENDLIST)) {
           extraLines.add(line);
-          return parseMediaPlaylist(new LineIterator(extraLines, reader), uri.toString());
+          return parseMediaPlaylist(
+              masterPlaylist, new LineIterator(extraLines, reader), uri.toString());
         } else {
           extraLines.add(line);
         }
@@ -402,14 +423,14 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
     return flags;
   }
 
-  private static HlsMediaPlaylist parseMediaPlaylist(LineIterator iterator, String baseUri)
+  private static HlsMediaPlaylist parseMediaPlaylist(
-      throws IOException {
+      HlsMasterPlaylist masterPlaylist, LineIterator iterator, String baseUri) throws IOException {
     @HlsMediaPlaylist.PlaylistType int playlistType = HlsMediaPlaylist.PLAYLIST_TYPE_UNKNOWN;
     long startOffsetUs = C.TIME_UNSET;
     long mediaSequence = 0;
     int version = 1; // Default version == 1.
     long targetDurationUs = C.TIME_UNSET;
-    boolean hasIndependentSegmentsTag = false;
+    boolean hasIndependentSegmentsTag = masterPlaylist.hasIndependentSegments;
     boolean hasEndTag = false;
     Segment initializationSegment = null;
     List<Segment> segments = new ArrayList<>();

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsPlaylistParserFactory.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2018 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 com.google.android.exoplayer2.source.hls.playlist;
+
+import com.google.android.exoplayer2.upstream.ParsingLoadable;
+
+/** Factory for {@link HlsPlaylist} parsers. */
+public interface HlsPlaylistParserFactory {
+
+  HlsPlaylistParserFactory DEFAULT =
+      new HlsPlaylistParserFactory() {
+        @Override
+        public ParsingLoadable.Parser<HlsPlaylist> createPlaylistParser() {
+          return new HlsPlaylistParser();
+        }
+
+        @Override
+        public ParsingLoadable.Parser<HlsPlaylist> createPlaylistParser(
+            HlsMasterPlaylist masterPlaylist) {
+          return new HlsPlaylistParser(masterPlaylist);
+        }
+      };
+
+  /**
+   * Returns a stand-alone playlist parser. Playlists parsed by the returned parser do not inherit
+   * any attributes from other playlists.
+   */
+  ParsingLoadable.Parser<HlsPlaylist> createPlaylistParser();
+
+  /**
+   * Returns a playlist parser for playlists that were referenced by the given {@link
+   * HlsMasterPlaylist}. Returned {@link HlsMediaPlaylist} instances may inherit attributes from
+   * {@code masterPlaylist}.
+   *
+   * @param masterPlaylist The master playlist that referenced any parsed media playlists.
+   * @return A parser for HLS playlists.
+   */
+  ParsingLoadable.Parser<HlsPlaylist> createPlaylistParser(HlsMasterPlaylist masterPlaylist);
+}

library/hls/src/test/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylistParserTest.java

@@ -383,10 +383,11 @@ public class HlsMediaPlaylistParserTest {
             + "#EXTINF:5.005,\n"
             + "02/00/47.ts\n";
     InputStream inputStream = new ByteArrayInputStream(Util.getUtf8Bytes(playlistString));
-    HlsMediaPlaylist playlist =
+    HlsMediaPlaylist standalonePlaylist =
         (HlsMediaPlaylist) new HlsPlaylistParser().parse(playlistUri, inputStream);
-    assertThat(playlist.hasIndependentSegments).isFalse();
+    assertThat(standalonePlaylist.hasIndependentSegments).isFalse();
 
+    inputStream.reset();
     HlsMasterPlaylist masterPlaylist =
         new HlsMasterPlaylist(
             /* baseUri= */ "https://example.com/",
@@ -397,7 +398,8 @@ public class HlsMediaPlaylistParserTest {
             /* muxedAudioFormat= */ null,
             /* muxedCaptionFormats= */ null,
             /* hasIndependentSegments= */ true);
-
+    HlsMediaPlaylist playlistWithInheritance =
-    assertThat(playlist.copyWithMasterPlaylistInfo(masterPlaylist).hasIndependentSegments).isTrue();
+        (HlsMediaPlaylist) new HlsPlaylistParser(masterPlaylist).parse(playlistUri, inputStream);
+    assertThat(playlistWithInheritance.hasIndependentSegments).isTrue();
   }
 }