Add recording capability to AudioManager, and implemented on windows using the WaveIn APIs.

media/audio/win/wavein_input_win.cc

+// Copyright (c) 2010 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/audio/win/wavein_input_win.h"
+
+#include <windows.h>
+#include <mmsystem.h>
+#pragma comment(lib, "winmm.lib")
+
+#include "base/basictypes.h"
+#include "base/logging.h"
+#include "media/audio/audio_io.h"
+#include "media/audio/audio_util.h"
+#include "media/audio/win/audio_manager_win.h"
+
+namespace {
+
+// Our sound buffers are allocated once and kept in a linked list using the
+// the WAVEHDR::dwUser variable. The last buffer points to the first buffer.
+WAVEHDR* GetNextBuffer(WAVEHDR* current) {
+  return reinterpret_cast<WAVEHDR*>(current->dwUser);
+}
+
+}  // namespace
+
+PCMWaveInAudioInputStream::PCMWaveInAudioInputStream(
+    AudioManagerWin* manager, int channels, int sampling_rate, int num_buffers,
+    char bits_per_sample, uint32 samples_per_packet, UINT device_id)
+    : state_(kStateEmpty),
+      manager_(manager),
+      device_id_(device_id),
+      wavein_(NULL),
+      callback_(NULL),
+      num_buffers_(num_buffers),
+      buffer_(NULL),
+      channels_(channels) {
+  format_.wFormatTag = WAVE_FORMAT_PCM;
+  format_.nChannels = channels > 2 ? 2 : channels;
+  format_.nSamplesPerSec = sampling_rate;
+  format_.wBitsPerSample = bits_per_sample;
+  format_.cbSize = 0;
+  format_.nBlockAlign = (format_.nChannels * format_.wBitsPerSample) / 8;
+  format_.nAvgBytesPerSec = format_.nBlockAlign * format_.nSamplesPerSec;
+  buffer_size_ = samples_per_packet * format_.nBlockAlign;
+  // If we don't have a packet size we use 100ms.
+  if (!buffer_size_)
+    buffer_size_ = format_.nAvgBytesPerSec / 10;
+  // The event is auto-reset.
+  stopped_event_.Set(::CreateEventW(NULL, FALSE, FALSE, NULL));
+}
+
+PCMWaveInAudioInputStream::~PCMWaveInAudioInputStream() {
+  DCHECK(NULL == wavein_);
+}
+
+bool PCMWaveInAudioInputStream::Open() {
+  if (state_ != kStateEmpty)
+    return false;
+  if (num_buffers_ < 2 || num_buffers_ > 10)
+    return false;
+  MMRESULT result = ::waveInOpen(&wavein_, device_id_, &format_,
+                                 reinterpret_cast<DWORD_PTR>(WaveCallback),
+                                 reinterpret_cast<DWORD_PTR>(this),
+                                 CALLBACK_FUNCTION);
+  if (result != MMSYSERR_NOERROR)
+    return false;
+
+  SetupBuffers();
+  state_ = kStateReady;
+  return true;
+}
+
+void PCMWaveInAudioInputStream::SetupBuffers() {
+  WAVEHDR* last = NULL;
+  WAVEHDR* first = NULL;
+  for (int ix = 0; ix != num_buffers_; ++ix) {
+    uint32 sz = sizeof(WAVEHDR) + buffer_size_;
+    buffer_ =  reinterpret_cast<WAVEHDR*>(new char[sz]);
+    buffer_->lpData = reinterpret_cast<char*>(buffer_) + sizeof(WAVEHDR);
+    buffer_->dwBufferLength = buffer_size_;
+    buffer_->dwBytesRecorded = 0;
+    buffer_->dwUser = reinterpret_cast<DWORD_PTR>(last);
+    buffer_->dwFlags = WHDR_DONE;
+    buffer_->dwLoops = 0;
+    if (ix == 0)
+      first = buffer_;
+    last = buffer_;
+    ::waveInPrepareHeader(wavein_, buffer_, sizeof(WAVEHDR));
+  }
+  // Fix the first buffer to point to the last one.
+  first->dwUser = reinterpret_cast<DWORD_PTR>(last);
+}
+
+void PCMWaveInAudioInputStream::FreeBuffers() {
+  WAVEHDR* current = buffer_;
+  for (int ix = 0; ix != num_buffers_; ++ix) {
+    WAVEHDR* next = GetNextBuffer(current);
+    if (current->dwFlags & WHDR_PREPARED)
+      ::waveInUnprepareHeader(wavein_, current, sizeof(WAVEHDR));
+    delete[] reinterpret_cast<char*>(current);
+    current = next;
+  }
+  buffer_ = NULL;
+}
+
+void PCMWaveInAudioInputStream::Start(AudioInputCallback* callback) {
+  if (state_ != kStateReady)
+    return;
+
+  callback_ = callback;
+  state_ = kStateRecording;
+
+  WAVEHDR* buffer = buffer_;
+  for (int ix = 0; ix != num_buffers_; ++ix) {
+    QueueNextPacket(buffer);
+    buffer = GetNextBuffer(buffer);
+  }
+  buffer = buffer_;
+
+  MMRESULT result = ::waveInStart(wavein_);
+  if (result != MMSYSERR_NOERROR) {
+    HandleError(result);
+    state_ = kStateReady;
+  }
+}
+
+// Stopping is tricky. First, no buffer should be locked by the audio driver
+// or else the waveInReset() will deadlock and secondly, the callback should
+// not be inside the AudioInputCallback's OnData because waveInReset()
+// forcefully kills the callback thread.
+void PCMWaveInAudioInputStream::Stop() {
+  if (state_ != kStateRecording)
+    return;
+  state_ = kStateStopping;
+  // Wait for the callback to finish, it will signal us when ready to be reset.
+  if (WAIT_OBJECT_0 != ::WaitForSingleObject(stopped_event_, INFINITE)) {
+    HandleError(::GetLastError());
+    return;
+  }
+  state_ = kStateStopped;
+  MMRESULT res = ::waveInReset(wavein_);
+  if (res != MMSYSERR_NOERROR) {
+    state_ = kStateRecording;
+    HandleError(res);
+    return;
+  }
+  state_ = kStateReady;
+}
+
+// We can Close in any state except that when trying to close a stream that is
+// recording Windows generates an error, which we propagate to the source.
+void PCMWaveInAudioInputStream::Close() {
+  if (wavein_) {
+    // waveInClose generates a callback with WIM_CLOSE id in the same thread.
+    MMRESULT res = ::waveInClose(wavein_);
+    if (res != MMSYSERR_NOERROR) {
+      HandleError(res);
+      return;
+    }
+    state_ = kStateClosed;
+    wavein_ = NULL;
+    FreeBuffers();
+  }
+  // Tell the audio manager that we have been released. This can result in
+  // the manager destroying us in-place so this needs to be the last thing
+  // we do on this function.
+  manager_->ReleaseInputStream(this);
+}
+
+void PCMWaveInAudioInputStream::HandleError(MMRESULT error) {
+  DLOG(WARNING) << "PCMWaveInAudio error " << error;
+  callback_->OnError(this, error);
+}
+
+void PCMWaveInAudioInputStream::QueueNextPacket(WAVEHDR *buffer) {
+  MMRESULT res = ::waveInAddBuffer(wavein_, buffer, sizeof(WAVEHDR));
+  if (res != MMSYSERR_NOERROR)
+    HandleError(res);
+}
+
+// Windows calls us back in this function when some events happen. Most notably
+// when it has an audio buffer with recorded data.
+void PCMWaveInAudioInputStream::WaveCallback(HWAVEIN hwi, UINT msg,
+                                             DWORD_PTR instance,
+                                             DWORD_PTR param1, DWORD_PTR) {
+  PCMWaveInAudioInputStream* obj =
+      reinterpret_cast<PCMWaveInAudioInputStream*>(instance);
+
+  if (msg == WIM_DATA) {
+    // WIM_DONE indicates that the driver is done with our buffer. We pass it
+    // to the callback and check if we need to stop playing.
+    WAVEHDR* buffer = reinterpret_cast<WAVEHDR*>(param1);
+    obj->callback_->OnData(obj, reinterpret_cast<const uint8*>(buffer->lpData),
+                           buffer->dwBytesRecorded);
+
+    if (obj->state_ == kStateStopping) {
+      // The main thread has called Stop() and is waiting to issue waveOutReset
+      // which will kill this thread. We should not enter AudioSourceCallback
+      // code anymore.
+      ::SetEvent(obj->stopped_event_);
+    } else if (obj->state_ == kStateStopped) {
+      // Not sure if ever hit this but just in case.
+    } else {
+      // Queue the finished buffer back with the audio driver. Since we are
+      // reusing the same buffers we can get away without calling
+      // waveInPrepareHeader.
+      obj->QueueNextPacket(buffer);
+    }
+  } else if (msg == WIM_CLOSE) {
+    // We can be closed before calling Start, so it is possible to have a
+    // null callback at this point.
+    if (obj->callback_)
+      obj->callback_->OnClose(obj);
+  }
+}