common/system_state.h

//
// Copyright (C) 2012 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.
//

#ifndef UPDATE_ENGINE_COMMON_SYSTEM_STATE_H_
#define UPDATE_ENGINE_COMMON_SYSTEM_STATE_H_

#include <memory>

#include <base/logging.h>

namespace chromeos_update_manager {

class UpdateManager;

}  // namespace chromeos_update_manager

namespace policy {

class DevicePolicy;

}  // namespace policy

namespace chromeos_update_engine {

// SystemState is the root class within the update engine. So we should avoid
// any circular references in header file inclusion. Hence forward-declaring
// the required classes.
class BootControlInterface;
class ClockInterface;
class ConnectionManagerInterface;
class DlcServiceInterface;
class HardwareInterface;
class MetricsReporterInterface;
class OmahaRequestParams;
class P2PManager;
class PayloadStateInterface;
class PowerManagerInterface;
class PrefsInterface;
class UpdateAttempter;

// An interface to global system context, including platform resources,
// the current state of the system, high-level objects whose lifetime is same
// as main, system interfaces, etc.
// Carved out separately so it can be mocked for unit tests.
class SystemState {
 public:
  virtual ~SystemState() = default;

  static SystemState* Get() {
    CHECK(g_instance_);
    return g_instance_.get();
  }

  // Sets or gets the latest device policy.
  virtual void set_device_policy(const policy::DevicePolicy* device_policy) = 0;
  virtual const policy::DevicePolicy* device_policy() = 0;

  // Gets the interface object for the bootloader control interface.
  virtual BootControlInterface* boot_control() = 0;

  // Gets the interface object for the clock.
  virtual ClockInterface* clock() = 0;

  // Gets the connection manager object.
  virtual ConnectionManagerInterface* connection_manager() = 0;

  // Gets the hardware interface object.
  virtual HardwareInterface* hardware() = 0;

  // Gets the Metrics Library interface for reporting UMA stats.
  virtual MetricsReporterInterface* metrics_reporter() = 0;

  // Gets the interface object for persisted store.
  virtual PrefsInterface* prefs() = 0;

  // Gets the interface object for the persisted store that persists across
  // powerwashes. Please note that this should be used very seldomly and must
  // be forwards and backwards compatible as powerwash is used to go back and
  // forth in system versions.
  virtual PrefsInterface* powerwash_safe_prefs() = 0;

  // Gets the interface for the payload state object.
  virtual PayloadStateInterface* payload_state() = 0;

  // Returns a pointer to the update attempter object.
  virtual UpdateAttempter* update_attempter() = 0;

  // Returns a pointer to the object that stores the parameters that are
  // common to all Omaha requests.
  virtual OmahaRequestParams* request_params() = 0;

  // Returns a pointer to the P2PManager singleton.
  virtual P2PManager* p2p_manager() = 0;

  // Returns a pointer to the UpdateManager singleton.
  virtual chromeos_update_manager::UpdateManager* update_manager() = 0;

  // Gets the power manager object. Mocked during test.
  virtual PowerManagerInterface* power_manager() = 0;

  // If true, this is the first instance of the update engine since the system
  // restarted. Important for tracking whether you are running instance of the
  // update engine on first boot or due to a crash/restart.
  virtual bool system_rebooted() = 0;

  // Returns a pointer to the DlcServiceInterface singleton.
  virtual DlcServiceInterface* dlcservice() = 0;

 protected:
  static std::unique_ptr<SystemState> g_instance_;
};

}  // namespace chromeos_update_engine

#endif  // UPDATE_ENGINE_COMMON_SYSTEM_STATE_H_