1 files changed, 143 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/audio/BaseAudioProcessor.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/audio/BaseAudioProcessor.java
new file mode 100644
index 0000000000..189d8f0265
--- /dev/null
+++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/audio/BaseAudioProcessor.java
@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 2019 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.audio;
+
+import androidx.annotation.CallSuper;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+
+/**
+ * Base class for audio processors that keep an output buffer and an internal buffer that is reused
+ * whenever input is queued. Subclasses should override {@link #onConfigure(AudioFormat)} to return
+ * the output audio format for the processor if it's active.
+ */
+public abstract class BaseAudioProcessor implements AudioProcessor {
+
+  /** The current input audio format. */
+  protected AudioFormat inputAudioFormat;
+  /** The current output audio format. */
+  protected AudioFormat outputAudioFormat;
+
+  private AudioFormat pendingInputAudioFormat;
+  private AudioFormat pendingOutputAudioFormat;
+  private ByteBuffer buffer;
+  private ByteBuffer outputBuffer;
+  private boolean inputEnded;
+
+  public BaseAudioProcessor() {
+    buffer = EMPTY_BUFFER;
+    outputBuffer = EMPTY_BUFFER;
+    pendingInputAudioFormat = AudioFormat.NOT_SET;
+    pendingOutputAudioFormat = AudioFormat.NOT_SET;
+    inputAudioFormat = AudioFormat.NOT_SET;
+    outputAudioFormat = AudioFormat.NOT_SET;
+  }
+
+  @Override
+  public final AudioFormat configure(AudioFormat inputAudioFormat)
+      throws UnhandledAudioFormatException {
+    pendingInputAudioFormat = inputAudioFormat;
+    pendingOutputAudioFormat = onConfigure(inputAudioFormat);
+    return isActive() ? pendingOutputAudioFormat : AudioFormat.NOT_SET;
+  }
+
+  @Override
+  public boolean isActive() {
+    return pendingOutputAudioFormat != AudioFormat.NOT_SET;
+  }
+
+  @Override
+  public final void queueEndOfStream() {
+    inputEnded = true;
+    onQueueEndOfStream();
+  }
+
+  @CallSuper
+  @Override
+  public ByteBuffer getOutput() {
+    ByteBuffer outputBuffer = this.outputBuffer;
+    this.outputBuffer = EMPTY_BUFFER;
+    return outputBuffer;
+  }
+
+  @CallSuper
+  @SuppressWarnings("ReferenceEquality")
+  @Override
+  public boolean isEnded() {
+    return inputEnded && outputBuffer == EMPTY_BUFFER;
+  }
+
+  @Override
+  public final void flush() {
+    outputBuffer = EMPTY_BUFFER;
+    inputEnded = false;
+    inputAudioFormat = pendingInputAudioFormat;
+    outputAudioFormat = pendingOutputAudioFormat;
+    onFlush();
+  }
+
+  @Override
+  public final void reset() {
+    flush();
+    buffer = EMPTY_BUFFER;
+    pendingInputAudioFormat = AudioFormat.NOT_SET;
+    pendingOutputAudioFormat = AudioFormat.NOT_SET;
+    inputAudioFormat = AudioFormat.NOT_SET;
+    outputAudioFormat = AudioFormat.NOT_SET;
+    onReset();
+  }
+
+  /**
+   * Replaces the current output buffer with a buffer of at least {@code count} bytes and returns
+   * it. Callers should write to the returned buffer then {@link ByteBuffer#flip()} it so it can be
+   * read via {@link #getOutput()}.
+   */
+  protected final ByteBuffer replaceOutputBuffer(int count) {
+    if (buffer.capacity() < count) {
+      buffer = ByteBuffer.allocateDirect(count).order(ByteOrder.nativeOrder());
+    } else {
+      buffer.clear();
+    }
+    outputBuffer = buffer;
+    return buffer;
+  }
+
+  /** Returns whether the current output buffer has any data remaining. */
+  protected final boolean hasPendingOutput() {
+    return outputBuffer.hasRemaining();
+  }
+
+  /** Called when the processor is configured for a new input format. */
+  protected AudioFormat onConfigure(AudioFormat inputAudioFormat)
+      throws UnhandledAudioFormatException {
+    return AudioFormat.NOT_SET;
+  }
+
+  /** Called when the end-of-stream is queued to the processor. */
+  protected void onQueueEndOfStream() {
+    // Do nothing.
+  }
+
+  /** Called when the processor is flushed, directly or as part of resetting. */
+  protected void onFlush() {
+    // Do nothing.
+  }
+
+  /** Called when the processor is reset. */
+  protected void onReset() {
+    // Do nothing.
+  }
+}