root/ppapi/examples/audio_input/audio_input.cc

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DEFINITIONS

This source file includes following definitions.
  1. waiting_for_flush_completion_
  2. Init
  3. DidChangeView
  4. HandleMessage
  5. ScheduleNextTimer
  6. OnTimer
  7. DidFlush
  8. Paint
  9. PaintImage
  10. Open
  11. Stop
  12. Start
  13. EnumerateDevicesFinished
  14. OpenFinished
  15. CaptureCallback
  16. MonitorDeviceChangeCallback
  17. CreateInstance
  18. CreateModule

// 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 <stdlib.h>
#include <string.h>

#include <algorithm>
#include <limits>
#include <vector>

#include "ppapi/cpp/audio_config.h"
#include "ppapi/cpp/dev/audio_input_dev.h"
#include "ppapi/cpp/dev/device_ref_dev.h"
#include "ppapi/cpp/graphics_2d.h"
#include "ppapi/cpp/image_data.h"
#include "ppapi/cpp/instance.h"
#include "ppapi/cpp/logging.h"
#include "ppapi/cpp/module.h"
#include "ppapi/cpp/rect.h"
#include "ppapi/cpp/size.h"
#include "ppapi/utility/completion_callback_factory.h"
#include "ppapi/utility/threading/lock.h"

// When compiling natively on Windows, PostMessage can be #define-d to
// something else.
#ifdef PostMessage
#undef PostMessage
#endif

namespace {

// This sample frequency is guaranteed to work.
const PP_AudioSampleRate kSampleFrequency = PP_AUDIOSAMPLERATE_44100;
const uint32_t kSampleCount = 1024;
const uint32_t kChannelCount = 1;
const char* const kDelimiter = "#__#";

}  // namespace

class MyInstance : public pp::Instance {
 public:
  explicit MyInstance(PP_Instance instance)
      : pp::Instance(instance),
        callback_factory_(this),
        sample_count_(0),
        channel_count_(0),
        samples_(NULL),
        latency_(0),
        timer_interval_(0),
        pending_paint_(false),
        waiting_for_flush_completion_(false) {
  }
  virtual ~MyInstance() {
    device_detector_.MonitorDeviceChange(NULL, NULL);
    audio_input_.Close();

    // The audio input thread has exited before the previous call returned, so
    // it is safe to do so now.
    delete[] samples_;
  }

  virtual bool Init(uint32_t argc, const char* argn[], const char* argv[]) {
    sample_count_ = pp::AudioConfig::RecommendSampleFrameCount(this,
                                                               kSampleFrequency,
                                                               kSampleCount);
    PP_DCHECK(sample_count_ > 0);
    channel_count_ = kChannelCount;
    samples_ = new int16_t[sample_count_ * channel_count_];
    memset(samples_, 0, sample_count_ * channel_count_ * sizeof(int16_t));

    device_detector_ = pp::AudioInput_Dev(this);

    // Try to ensure that we pick up a new set of samples between each
    // timer-generated repaint.
    timer_interval_ = (sample_count_ * 1000) / kSampleFrequency + 5;
    ScheduleNextTimer();

    return true;
  }

  virtual void DidChangeView(const pp::Rect& position, const pp::Rect& clip) {
    if (position.size() == size_)
      return;

    size_ = position.size();
    device_context_ = pp::Graphics2D(this, size_, false);
    if (!BindGraphics(device_context_))
      return;

    Paint();
  }

  virtual void HandleMessage(const pp::Var& message_data) {
    if (message_data.is_string()) {
      std::string event = message_data.AsString();
      if (event == "PageInitialized") {
        int32_t result = device_detector_.MonitorDeviceChange(
            &MyInstance::MonitorDeviceChangeCallback, this);
        if (result != PP_OK)
          PostMessage(pp::Var("MonitorDeviceChangeFailed"));

        pp::CompletionCallbackWithOutput<std::vector<pp::DeviceRef_Dev> >
            callback = callback_factory_.NewCallbackWithOutput(
                &MyInstance::EnumerateDevicesFinished);
        result = device_detector_.EnumerateDevices(callback);
        if (result != PP_OK_COMPLETIONPENDING)
          PostMessage(pp::Var("EnumerationFailed"));
      } else if (event == "UseDefault") {
        Open(pp::DeviceRef_Dev());
      } else if (event == "Stop") {
        Stop();
      } else if (event == "Start") {
        Start();
      } else if (event.find("Monitor:") == 0) {
        std::string index_str = event.substr(strlen("Monitor:"));
        int index = atoi(index_str.c_str());
        if (index >= 0 && index < static_cast<int>(monitor_devices_.size()))
          Open(monitor_devices_[index]);
        else
          PP_NOTREACHED();
      } else if (event.find("Enumerate:") == 0) {
        std::string index_str = event.substr(strlen("Enumerate:"));
        int index = atoi(index_str.c_str());
        if (index >= 0 && index < static_cast<int>(enumerate_devices_.size()))
          Open(enumerate_devices_[index]);
        else
          PP_NOTREACHED();
      }
    }
  }

 private:
  void ScheduleNextTimer() {
    PP_DCHECK(timer_interval_ > 0);
    pp::Module::Get()->core()->CallOnMainThread(
        timer_interval_,
        callback_factory_.NewCallback(&MyInstance::OnTimer),
        0);
  }

  void OnTimer(int32_t) {
    ScheduleNextTimer();
    Paint();
  }

  void DidFlush(int32_t result) {
    waiting_for_flush_completion_ = false;
    if (pending_paint_)
      Paint();
  }

  void Paint() {
    if (waiting_for_flush_completion_) {
      pending_paint_ = true;
      return;
    }

    pending_paint_ = false;

    if (size_.IsEmpty())
      return;  // Nothing to do.

    pp::ImageData image = PaintImage(size_);
    if (!image.is_null()) {
      device_context_.ReplaceContents(&image);
      waiting_for_flush_completion_ = true;
      device_context_.Flush(
          callback_factory_.NewCallback(&MyInstance::DidFlush));
    }
  }

  pp::ImageData PaintImage(const pp::Size& size) {
    pp::ImageData image(this, PP_IMAGEDATAFORMAT_BGRA_PREMUL, size, false);
    if (image.is_null())
      return image;

    // Clear to dark grey.
    for (int y = 0; y < size.height(); y++) {
      for (int x = 0; x < size.width(); x++)
        *image.GetAddr32(pp::Point(x, y)) = 0xff202020;
    }

    int mid_height = size.height() / 2;
    int max_amplitude = size.height() * 4 / 10;

    // Draw some lines.
    for (int x = 0; x < size.width(); x++) {
      *image.GetAddr32(pp::Point(x, mid_height)) = 0xff606060;
      *image.GetAddr32(pp::Point(x, mid_height + max_amplitude)) = 0xff404040;
      *image.GetAddr32(pp::Point(x, mid_height - max_amplitude)) = 0xff404040;
    }

    {
      pp::AutoLock auto_lock(lock_);

      // Draw the latency as a red bar at the bottom.
      PP_DCHECK(latency_ >= 0);
      int latency_bar_length =
          latency_ < 1 ? size.width() * latency_ : size.width();
      for (int x = 0; x < latency_bar_length; ++x) {
        *image.GetAddr32(pp::Point(x, mid_height + max_amplitude)) = 0xffff0000;
      }

      // Draw our samples.
      for (int x = 0, i = 0;
           x < std::min(size.width(), static_cast<int>(sample_count_));
           x++, i += channel_count_) {
        int y = samples_[i] * max_amplitude /
                (std::numeric_limits<int16_t>::max() + 1) + mid_height;
        *image.GetAddr32(pp::Point(x, y)) = 0xffffffff;
      }
    }

    return image;
  }

  void Open(const pp::DeviceRef_Dev& device) {
    audio_input_.Close();
    audio_input_ = pp::AudioInput_Dev(this);

    pp::AudioConfig config = pp::AudioConfig(this,
                                             kSampleFrequency,
                                             sample_count_);
    pp::CompletionCallback callback = callback_factory_.NewCallback(
        &MyInstance::OpenFinished);
    int32_t result = audio_input_.Open(device, config, CaptureCallback, this,
                                       callback);
    if (result != PP_OK_COMPLETIONPENDING)
      PostMessage(pp::Var("OpenFailed"));
  }

  void Stop() {
    if (!audio_input_.StopCapture())
      PostMessage(pp::Var("StopFailed"));
  }

  void Start() {
    if (!audio_input_.StartCapture())
      PostMessage(pp::Var("StartFailed"));
  }

  void EnumerateDevicesFinished(int32_t result,
                                std::vector<pp::DeviceRef_Dev>& devices) {
    if (result == PP_OK) {
      enumerate_devices_.swap(devices);
      std::string device_names = "Enumerate:";
      for (size_t index = 0; index < enumerate_devices_.size(); ++index) {
        pp::Var name = enumerate_devices_[index].GetName();
        PP_DCHECK(name.is_string());

        if (index != 0)
          device_names += kDelimiter;
        device_names += name.AsString();
      }
      PostMessage(pp::Var(device_names));
    } else {
      PostMessage(pp::Var("EnumerationFailed"));
    }
  }

  void OpenFinished(int32_t result) {
    if (result == PP_OK) {
      if (!audio_input_.StartCapture())
        PostMessage(pp::Var("StartFailed"));
    } else {
      PostMessage(pp::Var("OpenFailed"));
    }
  }

  static void CaptureCallback(const void* samples,
                              uint32_t num_bytes,
                              PP_TimeDelta latency,
                              void* ctx) {
    MyInstance* thiz = static_cast<MyInstance*>(ctx);
    pp::AutoLock auto_lock(thiz->lock_);
    thiz->latency_ = latency;
    uint32_t buffer_size =
        thiz->sample_count_ * thiz->channel_count_ * sizeof(int16_t);
    PP_DCHECK(num_bytes <= buffer_size);
    PP_DCHECK(num_bytes % (thiz->channel_count_ * sizeof(int16_t)) == 0);
    memcpy(thiz->samples_, samples, num_bytes);
    memset(reinterpret_cast<char*>(thiz->samples_) + num_bytes, 0,
           buffer_size - num_bytes);
  }

  static void MonitorDeviceChangeCallback(void* user_data,
                                          uint32_t device_count,
                                          const PP_Resource devices[]) {
    MyInstance* thiz = static_cast<MyInstance*>(user_data);

    std::string device_names = "Monitor:";
    thiz->monitor_devices_.clear();
    thiz->monitor_devices_.reserve(device_count);
    for (size_t index = 0; index < device_count; ++index) {
      thiz->monitor_devices_.push_back(pp::DeviceRef_Dev(devices[index]));
      pp::Var name = thiz->monitor_devices_.back().GetName();
      PP_DCHECK(name.is_string());

      if (index != 0)
        device_names += kDelimiter;
      device_names += name.AsString();
    }
    thiz->PostMessage(pp::Var(device_names));
  }

  pp::CompletionCallbackFactory<MyInstance> callback_factory_;

  uint32_t sample_count_;
  uint32_t channel_count_;
  int16_t* samples_;

  PP_TimeDelta latency_;

  int32_t timer_interval_;

  // Painting stuff.
  pp::Size size_;
  pp::Graphics2D device_context_;
  bool pending_paint_;
  bool waiting_for_flush_completion_;

  // There is no need to have two resources to do capturing and device detecting
  // separately. However, this makes the code of monitoring device change
  // easier.
  pp::AudioInput_Dev audio_input_;
  pp::AudioInput_Dev device_detector_;

  std::vector<pp::DeviceRef_Dev> enumerate_devices_;
  std::vector<pp::DeviceRef_Dev> monitor_devices_;

  // Protects |samples_| and |latency_|.
  pp::Lock lock_;
};

class MyModule : public pp::Module {
 public:
  virtual pp::Instance* CreateInstance(PP_Instance instance) {
    return new MyInstance(instance);
  }
};

namespace pp {

// Factory function for your specialization of the Module object.
Module* CreateModule() {
  return new MyModule();
}

}  // namespace pp

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