Android implementation of WebAudio audio file decoder

media/base/android/webaudio_media_codec_bridge.cc

+// Copyright (c) 2012 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.
+
+#include "media/base/android/webaudio_media_codec_bridge.h"
+
+#include <errno.h>
+#include <unistd.h>
+#include <vector>
+
+#include "base/android/jni_android.h"
+#include "base/android/jni_array.h"
+#include "base/android/jni_string.h"
+#include "base/basictypes.h"
+#include "base/logging.h"
+#include "jni/WebAudioMediaCodecBridge_jni.h"
+
+
+using base::android::AttachCurrentThread;
+
+namespace media {
+
+void WebAudioMediaCodecBridge::RunWebAudioMediaCodec(
+    base::SharedMemoryHandle encoded_audio_handle,
+    base::FileDescriptor pcm_output) {
+  DVLOG(0) << "RunWebAudioMediaCodec";

[palmer, 2013/04/11 20:29:51]

NIT: I still think you've got some log spam in the CL. I don't see that you need
to commit both of these DVLOG calls, for example.

+
+  WebAudioMediaCodecBridge bridge(encoded_audio_handle, pcm_output);
+  bool result = bridge.DecodeInMemoryAudioFile();
+  DVLOG(0) << "RunWebAudioMediaCodec returned " << result;
+}
+
+WebAudioMediaCodecBridge::WebAudioMediaCodecBridge(
+    base::SharedMemoryHandle encoded_audio_handle,
+    base::FileDescriptor pcm_output)
+    : encoded_audio_handle_(encoded_audio_handle.fd),
+      pcm_output_(pcm_output.fd) {
+  DVLOG(0) << "WebAudioMediaCodecBridge start **********************"
+           << "input fd = " << encoded_audio_handle_
+           << " output fd = " << pcm_output.fd;
+}
+
+WebAudioMediaCodecBridge::~WebAudioMediaCodecBridge() {
+  int result = close(pcm_output_);
+  if (result) {

[palmer, 2013/04/11 20:29:51]

NIT: These could be made smaller:

if (close(pcm_output_))
  DVLOG(0) << "Couldn't close output fd " << pcm_output_
                  << ": " << strerror(errno);

+    DVLOG(0) << "Couldn't close output fd " << pcm_output_;
+    DVLOG(0) << strerror(errno);
+  }
+
+  result = close(encoded_audio_handle_);
+  if (result) {
+    DVLOG(0) << "Couldn't close shared mem fd " << encoded_audio_handle_;
+    DVLOG(0) << strerror(errno);
+  }
+}
+
+bool WebAudioMediaCodecBridge::DecodeInMemoryAudioFile() {
+  // Process the encoded data from |encoded_data_handle_|.
+
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+  jboolean decoded = Java_WebAudioMediaCodecBridge_decodeAudioFile(
+      env,
+      base::android::GetApplicationContext(),
+      reinterpret_cast<intptr_t>(this),
+      encoded_audio_handle_);
+
+  DVLOG(0) << "decoded = " << static_cast<bool>(decoded);

[palmer, 2013/04/11 20:29:51]

I think that if you need the static_cast on this line, you also need it on the
next line. (I suspect you don't need it on either line.)

+  return decoded;
+}
+
+void WebAudioMediaCodecBridge::InitializeDestination(
+    JNIEnv* env,
+    jobject /*java object*/,
+    jint channel_count,
+    jint sample_rate,
+    jlong duration_microsec,
+    jboolean is_vorbis) {
+  // Send information about this audio file: number of channels,
+  // sample rate (Hz), number of frames, a flag indicating whether
+  // this file is an audio/vorbis file.  Information is sent as a set of
+  // 4 longs. This must be coordinated with DecodeAudioFileData!
+
+  unsigned long info[4] = {channel_count,
+                           sample_rate,
+                           // The number of frames is the duration of the file
+                           // (in microseconds) times the sample rate.
+                           0.5 + (duration_microsec * 0.000001 * sample_rate),
+                           is_vorbis ? 1 : 0};
+
+  DVLOG(0) << "InitializeDestination:"
+           << "  channel count = " << channel_count
+           << "  rate = " << sample_rate
+           << "  duration = " << duration_microsec << " microsec"
+           << "  vorbis = " << (is_vorbis ? "yes" : "no");
+
+  write(pcm_output_, info, sizeof(info));
+}
+
+void WebAudioMediaCodecBridge::OnChunkDecoded(
+    JNIEnv* env,
+    jobject /*java object*/,
+    jobject buf,
+    jint buf_size) {
+  int8_t* buffer =
+      static_cast<int8_t*>(env->GetDirectBufferAddress(buf));
+
+  // Write out the data to the pipe in small chunks if necessary.
+  while (buf_size > 0) {
+    int bytes_to_write = (buf_size >= PIPE_BUF) ? PIPE_BUF : buf_size;
+    ssize_t bytes_written = write(pcm_output_, buffer, bytes_to_write);

[palmer, 2013/04/11 20:29:51]

It might also make sense to use HANDLE_EINTR here.

+    if (bytes_written == -1)
+      break;
+    buf_size -= bytes_written;
+    buffer += bytes_written;
+  }
+}
+
+bool WebAudioMediaCodecBridge::RegisterWebAudioMediaCodecBridge(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+} // namespace