1 files changed, 226 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/source/hls/playlist/HlsPlaylistTracker.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/source/hls/playlist/HlsPlaylistTracker.java
new file mode 100644
index 0000000000..69f8cb02c9
--- /dev/null
+++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/source/hls/playlist/HlsPlaylistTracker.java
@@ -0,0 +1,226 @@
+/*
+ * 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 org.mozilla.thirdparty.com.google.android.exoplayer2.source.hls.playlist;
+
+import android.net.Uri;
+import androidx.annotation.Nullable;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.C;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.source.MediaSourceEventListener.EventDispatcher;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.source.hls.HlsDataSourceFactory;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.LoadErrorHandlingPolicy;
+import java.io.IOException;
+
+/**
+ * Tracks playlists associated to an HLS stream and provides snapshots.
+ *
+ * <p>The playlist tracker is responsible for exposing the seeking window, which is defined by the
+ * segments that one of the playlists exposes. This playlist is called primary and needs to be
+ * periodically refreshed in the case of live streams. Note that the primary playlist is one of the
+ * media playlists while the master playlist is an optional kind of playlist defined by the HLS
+ * specification (RFC 8216).
+ *
+ * <p>Playlist loads might encounter errors. The tracker may choose to blacklist them to ensure a
+ * primary playlist is always available.
+ */
+public interface HlsPlaylistTracker {
+
+  /** Factory for {@link HlsPlaylistTracker} instances. */
+  interface Factory {
+
+    /**
+     * Creates a new tracker instance.
+     *
+     * @param dataSourceFactory The {@link HlsDataSourceFactory} to use for playlist loading.
+     * @param loadErrorHandlingPolicy The {@link LoadErrorHandlingPolicy} for playlist load errors.
+     * @param playlistParserFactory The {@link HlsPlaylistParserFactory} for playlist parsing.
+     */
+    HlsPlaylistTracker createTracker(
+        HlsDataSourceFactory dataSourceFactory,
+        LoadErrorHandlingPolicy loadErrorHandlingPolicy,
+        HlsPlaylistParserFactory playlistParserFactory);
+  }
+
+  /** Listener for primary playlist changes. */
+  interface PrimaryPlaylistListener {
+
+    /**
+     * Called when the primary playlist changes.
+     *
+     * @param mediaPlaylist The primary playlist new snapshot.
+     */
+    void onPrimaryPlaylistRefreshed(HlsMediaPlaylist mediaPlaylist);
+  }
+
+  /** Called on playlist loading events. */
+  interface PlaylistEventListener {
+
+    /**
+     * Called a playlist changes.
+     */
+    void onPlaylistChanged();
+
+    /**
+     * Called if an error is encountered while loading a playlist.
+     *
+     * @param url The loaded url that caused the error.
+     * @param blacklistDurationMs The duration for which the playlist should be blacklisted. Or
+     *     {@link C#TIME_UNSET} if the playlist should not be blacklisted.
+     * @return True if blacklisting did not encounter errors. False otherwise.
+     */
+    boolean onPlaylistError(Uri url, long blacklistDurationMs);
+  }
+
+  /** Thrown when a playlist is considered to be stuck due to a server side error. */
+  final class PlaylistStuckException extends IOException {
+
+    /** The url of the stuck playlist. */
+    public final Uri url;
+
+    /**
+     * Creates an instance.
+     *
+     * @param url See {@link #url}.
+     */
+    public PlaylistStuckException(Uri url) {
+      this.url = url;
+    }
+  }
+
+  /** Thrown when the media sequence of a new snapshot indicates the server has reset. */
+  final class PlaylistResetException extends IOException {
+
+    /** The url of the reset playlist. */
+    public final Uri url;
+
+    /**
+     * Creates an instance.
+     *
+     * @param url See {@link #url}.
+     */
+    public PlaylistResetException(Uri url) {
+      this.url = url;
+    }
+  }
+
+  /**
+   * Starts the playlist tracker.
+   *
+   * <p>Must be called from the playback thread. A tracker may be restarted after a {@link #stop()}
+   * call.
+   *
+   * @param initialPlaylistUri Uri of the HLS stream. Can point to a media playlist or a master
+   *     playlist.
+   * @param eventDispatcher A dispatcher to notify of events.
+   * @param listener A callback for the primary playlist change events.
+   */
+  void start(
+      Uri initialPlaylistUri, EventDispatcher eventDispatcher, PrimaryPlaylistListener listener);
+
+  /**
+   * Stops the playlist tracker and releases any acquired resources.
+   *
+   * <p>Must be called once per {@link #start} call.
+   */
+  void stop();
+
+  /**
+   * Registers a listener to receive events from the playlist tracker.
+   *
+   * @param listener The listener.
+   */
+  void addListener(PlaylistEventListener listener);
+
+  /**
+   * Unregisters a listener.
+   *
+   * @param listener The listener to unregister.
+   */
+  void removeListener(PlaylistEventListener listener);
+
+  /**
+   * Returns the master playlist.
+   *
+   * <p>If the uri passed to {@link #start} points to a media playlist, an {@link HlsMasterPlaylist}
+   * with a single variant for said media playlist is returned.
+   *
+   * @return The master playlist. Null if the initial playlist has yet to be loaded.
+   */
+  @Nullable
+  HlsMasterPlaylist getMasterPlaylist();
+
+  /**
+   * Returns the most recent snapshot available of the playlist referenced by the provided {@link
+   * Uri}.
+   *
+   * @param url The {@link Uri} corresponding to the requested media playlist.
+   * @param isForPlayback Whether the caller might use the snapshot to request media segments for
+   *     playback. If true, the primary playlist may be updated to the one requested.
+   * @return The most recent snapshot of the playlist referenced by the provided {@link Uri}. May be
+   *     null if no snapshot has been loaded yet.
+   */
+  @Nullable
+  HlsMediaPlaylist getPlaylistSnapshot(Uri url, boolean isForPlayback);
+
+  /**
+   * Returns the start time of the first loaded primary playlist, or {@link C#TIME_UNSET} if no
+   * media playlist has been loaded.
+   */
+  long getInitialStartTimeUs();
+
+  /**
+   * Returns whether the snapshot of the playlist referenced by the provided {@link Uri} is valid,
+   * meaning all the segments referenced by the playlist are expected to be available. If the
+   * playlist is not valid then some of the segments may no longer be available.
+   *
+   * @param url The {@link Uri}.
+   * @return Whether the snapshot of the playlist referenced by the provided {@link Uri} is valid.
+   */
+  boolean isSnapshotValid(Uri url);
+
+  /**
+   * If the tracker is having trouble refreshing the master playlist or the primary playlist, this
+   * method throws the underlying error. Otherwise, does nothing.
+   *
+   * @throws IOException The underlying error.
+   */
+  void maybeThrowPrimaryPlaylistRefreshError() throws IOException;
+
+  /**
+   * If the playlist is having trouble refreshing the playlist referenced by the given {@link Uri},
+   * this method throws the underlying error.
+   *
+   * @param url The {@link Uri}.
+   * @throws IOException The underyling error.
+   */
+  void maybeThrowPlaylistRefreshError(Uri url) throws IOException;
+
+  /**
+   * Requests a playlist refresh and whitelists it.
+   *
+   * <p>The playlist tracker may choose the delay the playlist refresh. The request is discarded if
+   * a refresh was already pending.
+   *
+   * @param url The {@link Uri} of the playlist to be refreshed.
+   */
+  void refreshPlaylist(Uri url);
+
+  /**
+   * Returns whether the tracked playlists describe a live stream.
+   *
+   * @return True if the content is live. False otherwise.
+   */
+  boolean isLive();
+}