1 files changed, 314 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/decoder/SimpleDecoder.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/decoder/SimpleDecoder.java
new file mode 100644
index 0000000000..a193ad3c8e
--- /dev/null
+++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/decoder/SimpleDecoder.java
@@ -0,0 +1,314 @@
+/*
+ * Copyright (C) 2016 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.decoder;
+
+import androidx.annotation.CallSuper;
+import androidx.annotation.Nullable;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.C;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Assertions;
+import java.util.ArrayDeque;
+
+/** Base class for {@link Decoder}s that use their own decode thread. */
+@SuppressWarnings("UngroupedOverloads")
+public abstract class SimpleDecoder<
+        I extends DecoderInputBuffer, O extends OutputBuffer, E extends Exception>
+    implements Decoder<I, O, E> {
+
+  private final Thread decodeThread;
+
+  private final Object lock;
+  private final ArrayDeque<I> queuedInputBuffers;
+  private final ArrayDeque<O> queuedOutputBuffers;
+  private final I[] availableInputBuffers;
+  private final O[] availableOutputBuffers;
+
+  private int availableInputBufferCount;
+  private int availableOutputBufferCount;
+  private I dequeuedInputBuffer;
+
+  private E exception;
+  private boolean flushed;
+  private boolean released;
+  private int skippedOutputBufferCount;
+
+  /**
+   * @param inputBuffers An array of nulls that will be used to store references to input buffers.
+   * @param outputBuffers An array of nulls that will be used to store references to output buffers.
+   */
+  protected SimpleDecoder(I[] inputBuffers, O[] outputBuffers) {
+    lock = new Object();
+    queuedInputBuffers = new ArrayDeque<>();
+    queuedOutputBuffers = new ArrayDeque<>();
+    availableInputBuffers = inputBuffers;
+    availableInputBufferCount = inputBuffers.length;
+    for (int i = 0; i < availableInputBufferCount; i++) {
+      availableInputBuffers[i] = createInputBuffer();
+    }
+    availableOutputBuffers = outputBuffers;
+    availableOutputBufferCount = outputBuffers.length;
+    for (int i = 0; i < availableOutputBufferCount; i++) {
+      availableOutputBuffers[i] = createOutputBuffer();
+    }
+    decodeThread = new Thread() {
+      @Override
+      public void run() {
+        SimpleDecoder.this.run();
+      }
+    };
+    decodeThread.start();
+  }
+
+  /**
+   * Sets the initial size of each input buffer.
+   * <p>
+   * This method should only be called before the decoder is used (i.e. before the first call to
+   * {@link #dequeueInputBuffer()}.
+   *
+   * @param size The required input buffer size.
+   */
+  protected final void setInitialInputBufferSize(int size) {
+    Assertions.checkState(availableInputBufferCount == availableInputBuffers.length);
+    for (I inputBuffer : availableInputBuffers) {
+      inputBuffer.ensureSpaceForWrite(size);
+    }
+  }
+
+  @Override
+  @Nullable
+  public final I dequeueInputBuffer() throws E {
+    synchronized (lock) {
+      maybeThrowException();
+      Assertions.checkState(dequeuedInputBuffer == null);
+      dequeuedInputBuffer = availableInputBufferCount == 0 ? null
+          : availableInputBuffers[--availableInputBufferCount];
+      return dequeuedInputBuffer;
+    }
+  }
+
+  @Override
+  public final void queueInputBuffer(I inputBuffer) throws E {
+    synchronized (lock) {
+      maybeThrowException();
+      Assertions.checkArgument(inputBuffer == dequeuedInputBuffer);
+      queuedInputBuffers.addLast(inputBuffer);
+      maybeNotifyDecodeLoop();
+      dequeuedInputBuffer = null;
+    }
+  }
+
+  @Override
+  @Nullable
+  public final O dequeueOutputBuffer() throws E {
+    synchronized (lock) {
+      maybeThrowException();
+      if (queuedOutputBuffers.isEmpty()) {
+        return null;
+      }
+      return queuedOutputBuffers.removeFirst();
+    }
+  }
+
+  /**
+   * Releases an output buffer back to the decoder.
+   *
+   * @param outputBuffer The output buffer being released.
+   */
+  @CallSuper
+  protected void releaseOutputBuffer(O outputBuffer) {
+    synchronized (lock) {
+      releaseOutputBufferInternal(outputBuffer);
+      maybeNotifyDecodeLoop();
+    }
+  }
+
+  @Override
+  public final void flush() {
+    synchronized (lock) {
+      flushed = true;
+      skippedOutputBufferCount = 0;
+      if (dequeuedInputBuffer != null) {
+        releaseInputBufferInternal(dequeuedInputBuffer);
+        dequeuedInputBuffer = null;
+      }
+      while (!queuedInputBuffers.isEmpty()) {
+        releaseInputBufferInternal(queuedInputBuffers.removeFirst());
+      }
+      while (!queuedOutputBuffers.isEmpty()) {
+        queuedOutputBuffers.removeFirst().release();
+      }
+      exception = null;
+    }
+  }
+
+  @CallSuper
+  @Override
+  public void release() {
+    synchronized (lock) {
+      released = true;
+      lock.notify();
+    }
+    try {
+      decodeThread.join();
+    } catch (InterruptedException e) {
+      Thread.currentThread().interrupt();
+    }
+  }
+
+  /**
+   * Throws a decode exception, if there is one.
+   *
+   * @throws E The decode exception.
+   */
+  private void maybeThrowException() throws E {
+    if (exception != null) {
+      throw exception;
+    }
+  }
+
+  /**
+   * Notifies the decode loop if there exists a queued input buffer and an available output buffer
+   * to decode into.
+   * <p>
+   * Should only be called whilst synchronized on the lock object.
+   */
+  private void maybeNotifyDecodeLoop() {
+    if (canDecodeBuffer()) {
+      lock.notify();
+    }
+  }
+
+  private void run() {
+    try {
+      while (decode()) {
+        // Do nothing.
+      }
+    } catch (InterruptedException e) {
+      // Not expected.
+      throw new IllegalStateException(e);
+    }
+  }
+
+  private boolean decode() throws InterruptedException {
+    I inputBuffer;
+    O outputBuffer;
+    boolean resetDecoder;
+
+    // Wait until we have an input buffer to decode, and an output buffer to decode into.
+    synchronized (lock) {
+      while (!released && !canDecodeBuffer()) {
+        lock.wait();
+      }
+      if (released) {
+        return false;
+      }
+      inputBuffer = queuedInputBuffers.removeFirst();
+      outputBuffer = availableOutputBuffers[--availableOutputBufferCount];
+      resetDecoder = flushed;
+      flushed = false;
+    }
+
+    if (inputBuffer.isEndOfStream()) {
+      outputBuffer.addFlag(C.BUFFER_FLAG_END_OF_STREAM);
+    } else {
+      if (inputBuffer.isDecodeOnly()) {
+        outputBuffer.addFlag(C.BUFFER_FLAG_DECODE_ONLY);
+      }
+      @Nullable E exception;
+      try {
+        exception = decode(inputBuffer, outputBuffer, resetDecoder);
+      } catch (RuntimeException e) {
+        // This can occur if a sample is malformed in a way that the decoder is not robust against.
+        // We don't want the process to die in this case, but we do want to propagate the error.
+        exception = createUnexpectedDecodeException(e);
+      } catch (OutOfMemoryError e) {
+        // This can occur if a sample is malformed in a way that causes the decoder to think it
+        // needs to allocate a large amount of memory. We don't want the process to die in this
+        // case, but we do want to propagate the error.
+        exception = createUnexpectedDecodeException(e);
+      }
+      if (exception != null) {
+        synchronized (lock) {
+          this.exception = exception;
+        }
+        return false;
+      }
+    }
+
+    synchronized (lock) {
+      if (flushed) {
+        outputBuffer.release();
+      } else if (outputBuffer.isDecodeOnly()) {
+        skippedOutputBufferCount++;
+        outputBuffer.release();
+      } else {
+        outputBuffer.skippedOutputBufferCount = skippedOutputBufferCount;
+        skippedOutputBufferCount = 0;
+        queuedOutputBuffers.addLast(outputBuffer);
+      }
+      // Make the input buffer available again.
+      releaseInputBufferInternal(inputBuffer);
+    }
+
+    return true;
+  }
+
+  private boolean canDecodeBuffer() {
+    return !queuedInputBuffers.isEmpty() && availableOutputBufferCount > 0;
+  }
+
+  private void releaseInputBufferInternal(I inputBuffer) {
+    inputBuffer.clear();
+    availableInputBuffers[availableInputBufferCount++] = inputBuffer;
+  }
+
+  private void releaseOutputBufferInternal(O outputBuffer) {
+    outputBuffer.clear();
+    availableOutputBuffers[availableOutputBufferCount++] = outputBuffer;
+  }
+
+  /**
+   * Creates a new input buffer.
+   */
+  protected abstract I createInputBuffer();
+
+  /**
+   * Creates a new output buffer.
+   */
+  protected abstract O createOutputBuffer();
+
+  /**
+   * Creates an exception to propagate for an unexpected decode error.
+   *
+   * @param error The unexpected decode error.
+   * @return The exception to propagate.
+   */
+  protected abstract E createUnexpectedDecodeException(Throwable error);
+
+  /**
+   * Decodes the {@code inputBuffer} and stores any decoded output in {@code outputBuffer}.
+   *
+   * @param inputBuffer The buffer to decode.
+   * @param outputBuffer The output buffer to store decoded data. The flag {@link
+   *     C#BUFFER_FLAG_DECODE_ONLY} will be set if the same flag is set on {@code inputBuffer}, but
+   *     may be set/unset as required. If the flag is set when the call returns then the output
+   *     buffer will not be made available to dequeue. The output buffer may not have been populated
+   *     in this case.
+   * @param reset Whether the decoder must be reset before decoding.
+   * @return A decoder exception if an error occurred, or null if decoding was successful.
+   */
+  @Nullable
+  protected abstract E decode(I inputBuffer, O outputBuffer, boolean reset);
+}