media/brillo/audio/audioservice/audio_daemon.h

// Copyright 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.
//

// Main loop of the brillo audio service.

#ifndef BRILLO_AUDIO_AUDIOSERVICE_AUDIO_DAEMON_H_
#define BRILLO_AUDIO_AUDIOSERVICE_AUDIO_DAEMON_H_

#include <memory>
#include <stack>
#include <vector>

#include <base/files/file.h>
#include <base/memory/weak_ptr.h>
#include <brillo/binder_watcher.h>
#include <brillo/daemons/daemon.h>
#include <media/IAudioPolicyService.h>

#include "audio_device_handler.h"
#include "audio_volume_handler.h"
#include "brillo_audio_service.h"

namespace brillo {

class AudioDaemon : public Daemon {
 public:
  AudioDaemon() {}
  virtual ~AudioDaemon();

 protected:
  // Initialize the audio daemon handlers and start pollig the files in
  // /dev/input.
  int OnInit() override;

 private:
  friend class AudioDaemonTest;
  FRIEND_TEST(AudioDaemonTest, RegisterService);
  FRIEND_TEST(AudioDaemonTest, TestAPSConnectInitializesHandlersOnlyOnce);
  FRIEND_TEST(AudioDaemonTest, TestDeviceCallbackInitializesBASIfNULL);

  // Callback function for input events. Events are handled by the audio device
  // handler.
  void EventCallback(base::File* file);

  // Callback function for device state changes. Events are handler by the
  // audio service.
  //
  // |mode| is kDevicesConnected when |devices| are connected.
  // |devices| is a vector of integers representing audio_devices_t.
  void DeviceCallback(AudioDeviceHandler::DeviceConnectionState,
                      const std::vector<int>& devices);

  // Callback function when volume changes.
  //
  // |stream| is an audio_stream_type_t representing the stream.
  // |previous_index| is the volume index before the key press.
  // |current_index| is the volume index after the key press.
  void VolumeCallback(audio_stream_type_t stream,
                      int previous_index,
                      int current_index);

  // Callback function for audio policy service death notification.
  void OnAPSDisconnected();

  // Connect to the audio policy service and register a callback to be invoked
  // if the audio policy service dies.
  void ConnectToAPS();

  // Register the brillo audio service with the service manager.
  void InitializeBrilloAudioService();

  // Initialize all audio daemon handlers.
  //
  // Note: This can only occur after we have connected to the audio policy
  // service.
  virtual void InitializeHandlers();

  // Store the file objects that are created during initialization for the files
  // being polled. This is done so these objects can be freed when the
  // AudioDaemon object is destroyed.
  std::stack<base::File> files_;
  // Handler for audio device input events.
  std::shared_ptr<AudioDeviceHandler> audio_device_handler_;
  // Handler for volume key press input events.
  std::shared_ptr<AudioVolumeHandler> audio_volume_handler_;
  // Used to generate weak_ptr to AudioDaemon for use in base::Bind.
  base::WeakPtrFactory<AudioDaemon> weak_ptr_factory_{this};
  // Pointer to the audio policy service.
  android::sp<android::IAudioPolicyService> aps_;
  // Flag to indicate whether the handlers have been initialized.
  bool handlers_initialized_ = false;
  // Binder watcher to watch for binder messages.
  BinderWatcher binder_watcher_;
  // Brillo audio service. Used for scheduling callbacks to clients.
  android::sp<BrilloAudioService> brillo_audio_service_;
};

}  // namespace brillo

#endif  // BRILLO_AUDIO_AUDIOSERVICE_AUDIO_DAEMON_H_