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/*
* Copyright (c) 2018, Ford Motor Company
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following
* disclaimer in the documentation and/or other materials provided with the
* distribution.
*
* Neither the name of the Ford Motor Company nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef SRC_COMPONENTS_UTILS_INCLUDE_UTILS_SYSTEM_TIME_HANDLER_H_
#define SRC_COMPONENTS_UTILS_INCLUDE_UTILS_SYSTEM_TIME_HANDLER_H_
#include <time.h>
namespace utils {
/**
* @brief The SystemTimeListener interface.
* This interface allows to get notifications whenever
* system time appears or fails to appear.
*/
class SystemTimeListener {
public:
/**
* @brief OnSystemTimeArrived Notify about system time
* in utc format
* @param utc_time current system time.
*/
virtual void OnSystemTimeArrived(const time_t utc_time) = 0;
};
/**
* @brief SystemTimeHandler the interface which provides the necessary
* public API to work with system time. The class does not implement
* any logic it's public api forwards call to the private virtual
* methods which are suppose to be defined within specific implementation.
*/
class SystemTimeHandler {
public:
/**
* @brief SystemTimeHandler creates an instance
* for this class.
*/
SystemTimeHandler();
/**
* @brief QuerySystemTime provides the public interface
* to retrieve the system time. Interface uses private implementation
* hence the logic will be defined within descendant class.
*/
void QuerySystemTime();
/**
* @brief SubscribeOnSystemTime allows to subscribe listener
* to the certain event. This class does not provide such storage.
* It rather uses private pure virtual function. So the final behaviour
* should be defined within the descendant class
*/
void SubscribeOnSystemTime(SystemTimeListener* listener);
/**
* @brief UnsubscribeFromSystemTime allows to unsubscribe listener
* from the certain event. This class does not manipulate with storage.
* It rather uses private pure virtual function. So the final behaviour
* should be defined within the descendant class
*/
void UnsubscribeFromSystemTime(SystemTimeListener* listener);
/**
* @brief GetUTCTime allows to obtain cached result for the
* GetSystemTime request
* @return utc time.
*/
time_t GetUTCTime();
/**
* @brief Checks if system time is ready
* and can be requested by GetSystemTime request
* @return True if HMI is ready to provide UTC time
* otherwise False
*/
bool system_time_can_be_received() const;
/**
* @brief ~SystemTimeHandler destroys the object
*/
virtual ~SystemTimeHandler();
private:
/**
* @brief DoSystemTimeQuery responsible for the system time querying.
* It is up to implementator how exactly system is going to receive this time.
*/
virtual void DoSystemTimeQuery() = 0;
/**
* @brief DoSubscribe implements the logic which allows to handle
* subscription process. The handling logic should be defined within
* descendant class.
*/
virtual void DoSubscribe(SystemTimeListener* listener) = 0;
/**
* @brief DoUnsubscribe implements the logic which allows to handle
* unsubscription process. The handling logic should be defined within
* descendant class.
*/
virtual void DoUnsubscribe(SystemTimeListener* listener) = 0;
/**
* @brief FetchSystemTime allows to obtain the cached result
* for the GetSystemTime request.
* @return utc time.
*/
virtual time_t FetchSystemTime() = 0;
/**
* @brief Checks if UTC time is ready to provided by HMI
* and can be requested by GetSystemTime request
* @return True if HMI is ready to provide UTC time
* otherwise False
*/
virtual bool utc_time_can_be_received() const = 0;
};
} // namespace utils
#endif // SRC_COMPONENTS_UTILS_INCLUDE_UTILS_SYSTEM_TIME_HANDLER_H_
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