Android implementation of WebAudio audio file decoder

media/base/android/webaudio_media_codec_bridge.h

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_BASE_ANDROID_MEDIA_CODEC_BRIDGE_H_
+#define MEDIA_BASE_ANDROID_MEDIA_CODEC_BRIDGE_H_
+
+#include <jni.h>
+
+#include "base/file_descriptor_posix.h"
+#include "base/shared_memory.h"
+#include "media/base/media_export.h"
+
+namespace media {
+
+// This class serves as a bridge for native code to call java functions inside
+// android mediaplayer class. For more information on android mediaplayer, check
+// http://developer.android.com/reference/android/media/MediaPlayer.html
+// The actual android mediaplayer instance is created lazily when Start(),
+// Pause(), SeekTo() gets called. As a result, media information may not
+// be available until one of those operations is performed. After that, we
+// will cache those information in case the mediaplayer gets released.
+class MEDIA_EXPORT WebAudioMediaCodecBridge {
+public:
+  WebAudioMediaCodecBridge(base::SharedMemoryHandle input_fd,
+                           base::FileDescriptor output_fd);
+  ~WebAudioMediaCodecBridge();
+
+  bool DecodeInMemoryAudioFile();
+  static bool RegisterWebAudioMediaCodecBridge(JNIEnv* env);
+  static void RunWebAudioMediaCodec(base::SharedMemoryHandle input_fd,
+                                    base::FileDescriptor output_fd);
+
+  void OnChunkDecoded(JNIEnv* env,
+                      jobject /*java object*/,
+                      jobject buf,
+                      jint buf_size);
+
+  void InitializeDestination(JNIEnv* env,
+                             jobject /*java object*/,
+                             jint number_of_channels,
+                             jint sample_rate,
+                             jlong duration_us,
+                             jboolean is_vorbis);
+
+private:
+  JNIEnv* env_;
+  jobject j_context_;

[bulach, 2013/03/28 13:39:25]

nit: better not cache these two... JNIEnv* should be obtained by
AttachCurrentThread(), and context via base::android::GetApplicationContext()

+
+  int input_fd_;
+  int output_fd_;
+};
+
+}  // namespace media
+#endif  // MEDIA_BASE_ANDROID_MEDIA_CODEC_BRIDGE_H_