1 files changed, 191 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/source/BaseMediaSource.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/source/BaseMediaSource.java
new file mode 100644
index 0000000000..f9ca6ff311
--- /dev/null
+++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/source/BaseMediaSource.java
@@ -0,0 +1,191 @@
+/*
+ * 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;
+
+import android.os.Handler;
+import android.os.Looper;
+import androidx.annotation.Nullable;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.Timeline;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.TransferListener;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Assertions;
+import java.util.ArrayList;
+import java.util.HashSet;
+
+/**
+ * Base {@link MediaSource} implementation to handle parallel reuse and to keep a list of {@link
+ * MediaSourceEventListener}s.
+ *
+ * <p>Whenever an implementing subclass needs to provide a new timeline, it must call {@link
+ * #refreshSourceInfo(Timeline)} to notify all listeners.
+ */
+public abstract class BaseMediaSource implements MediaSource {
+
+  private final ArrayList<MediaSourceCaller> mediaSourceCallers;
+  private final HashSet<MediaSourceCaller> enabledMediaSourceCallers;
+  private final MediaSourceEventListener.EventDispatcher eventDispatcher;
+
+  @Nullable private Looper looper;
+  @Nullable private Timeline timeline;
+
+  public BaseMediaSource() {
+    mediaSourceCallers = new ArrayList<>(/* initialCapacity= */ 1);
+    enabledMediaSourceCallers = new HashSet<>(/* initialCapacity= */ 1);
+    eventDispatcher = new MediaSourceEventListener.EventDispatcher();
+  }
+
+  /**
+   * Starts source preparation and enables the source, see {@link #prepareSource(MediaSourceCaller,
+   * TransferListener)}. This method is called at most once until the next call to {@link
+   * #releaseSourceInternal()}.
+   *
+   * @param mediaTransferListener The transfer listener which should be informed of any media data
+   *     transfers. May be null if no listener is available. Note that this listener should usually
+   *     be only informed of transfers related to the media loads and not of auxiliary loads for
+   *     manifests and other data.
+   */
+  protected abstract void prepareSourceInternal(@Nullable TransferListener mediaTransferListener);
+
+  /** Enables the source, see {@link #enable(MediaSourceCaller)}. */
+  protected void enableInternal() {}
+
+  /** Disables the source, see {@link #disable(MediaSourceCaller)}. */
+  protected void disableInternal() {}
+
+  /**
+   * Releases the source, see {@link #releaseSource(MediaSourceCaller)}. This method is called
+   * exactly once after each call to {@link #prepareSourceInternal(TransferListener)}.
+   */
+  protected abstract void releaseSourceInternal();
+
+  /**
+   * Updates timeline and manifest and notifies all listeners of the update.
+   *
+   * @param timeline The new {@link Timeline}.
+   */
+  protected final void refreshSourceInfo(Timeline timeline) {
+    this.timeline = timeline;
+    for (MediaSourceCaller caller : mediaSourceCallers) {
+      caller.onSourceInfoRefreshed(/* source= */ this, timeline);
+    }
+  }
+
+  /**
+   * Returns a {@link MediaSourceEventListener.EventDispatcher} which dispatches all events to the
+   * registered listeners with the specified media period id.
+   *
+   * @param mediaPeriodId The {@link MediaPeriodId} to be reported with the events. May be null, if
+   *     the events do not belong to a specific media period.
+   * @return An event dispatcher with pre-configured media period id.
+   */
+  protected final MediaSourceEventListener.EventDispatcher createEventDispatcher(
+      @Nullable MediaPeriodId mediaPeriodId) {
+    return eventDispatcher.withParameters(
+        /* windowIndex= */ 0, mediaPeriodId, /* mediaTimeOffsetMs= */ 0);
+  }
+
+  /**
+   * Returns a {@link MediaSourceEventListener.EventDispatcher} which dispatches all events to the
+   * registered listeners with the specified media period id and time offset.
+   *
+   * @param mediaPeriodId The {@link MediaPeriodId} to be reported with the events.
+   * @param mediaTimeOffsetMs The offset to be added to all media times, in milliseconds.
+   * @return An event dispatcher with pre-configured media period id and time offset.
+   */
+  protected final MediaSourceEventListener.EventDispatcher createEventDispatcher(
+      MediaPeriodId mediaPeriodId, long mediaTimeOffsetMs) {
+    Assertions.checkArgument(mediaPeriodId != null);
+    return eventDispatcher.withParameters(/* windowIndex= */ 0, mediaPeriodId, mediaTimeOffsetMs);
+  }
+
+  /**
+   * Returns a {@link MediaSourceEventListener.EventDispatcher} which dispatches all events to the
+   * registered listeners with the specified window index, media period id and time offset.
+   *
+   * @param windowIndex The timeline window index to be reported with the events.
+   * @param mediaPeriodId The {@link MediaPeriodId} to be reported with the events. May be null, if
+   *     the events do not belong to a specific media period.
+   * @param mediaTimeOffsetMs The offset to be added to all media times, in milliseconds.
+   * @return An event dispatcher with pre-configured media period id and time offset.
+   */
+  protected final MediaSourceEventListener.EventDispatcher createEventDispatcher(
+      int windowIndex, @Nullable MediaPeriodId mediaPeriodId, long mediaTimeOffsetMs) {
+    return eventDispatcher.withParameters(windowIndex, mediaPeriodId, mediaTimeOffsetMs);
+  }
+
+  /** Returns whether the source is enabled. */
+  protected final boolean isEnabled() {
+    return !enabledMediaSourceCallers.isEmpty();
+  }
+
+  @Override
+  public final void addEventListener(Handler handler, MediaSourceEventListener eventListener) {
+    eventDispatcher.addEventListener(handler, eventListener);
+  }
+
+  @Override
+  public final void removeEventListener(MediaSourceEventListener eventListener) {
+    eventDispatcher.removeEventListener(eventListener);
+  }
+
+  @Override
+  public final void prepareSource(
+      MediaSourceCaller caller, @Nullable TransferListener mediaTransferListener) {
+    Looper looper = Looper.myLooper();
+    Assertions.checkArgument(this.looper == null || this.looper == looper);
+    Timeline timeline = this.timeline;
+    mediaSourceCallers.add(caller);
+    if (this.looper == null) {
+      this.looper = looper;
+      enabledMediaSourceCallers.add(caller);
+      prepareSourceInternal(mediaTransferListener);
+    } else if (timeline != null) {
+      enable(caller);
+      caller.onSourceInfoRefreshed(/* source= */ this, timeline);
+    }
+  }
+
+  @Override
+  public final void enable(MediaSourceCaller caller) {
+    Assertions.checkNotNull(looper);
+    boolean wasDisabled = enabledMediaSourceCallers.isEmpty();
+    enabledMediaSourceCallers.add(caller);
+    if (wasDisabled) {
+      enableInternal();
+    }
+  }
+
+  @Override
+  public final void disable(MediaSourceCaller caller) {
+    boolean wasEnabled = !enabledMediaSourceCallers.isEmpty();
+    enabledMediaSourceCallers.remove(caller);
+    if (wasEnabled && enabledMediaSourceCallers.isEmpty()) {
+      disableInternal();
+    }
+  }
+
+  @Override
+  public final void releaseSource(MediaSourceCaller caller) {
+    mediaSourceCallers.remove(caller);
+    if (mediaSourceCallers.isEmpty()) {
+      looper = null;
+      timeline = null;
+      enabledMediaSourceCallers.clear();
+      releaseSourceInternal();
+    } else {
+      disable(caller);
+    }
+  }
+}