bmc_epoch.hpp

#pragma once

#include "epoch_base.hpp"

#include <chrono>

namespace phosphor
{
namespace time
{

using namespace std::chrono;

/** @class BmcEpoch
 *  @brief OpenBMC BMC EpochTime implementation.
 *  @details A concrete implementation for xyz.openbmc_project.Time.EpochTime
 *  DBus API for BMC's epoch time.
 */
class BmcEpoch : public EpochBase
{
  public:
    BmcEpoch(sdbusplus::bus_t& bus, const char* objPath, Manager& manager);
    ~BmcEpoch();

    /**
     * @brief Get value of Elapsed property
     *
     * @return The elapsed microseconds since UTC
     **/
    uint64_t elapsed() const override;

    /**
     * @brief Set value of Elapsed property
     *
     * @param[in] value - The microseconds since UTC to set
     * @return The updated elapsed microseconds since UTC
     **/
    uint64_t elapsed(uint64_t value) override;

  private:
    /** @brief The fd for time change event */
    int timeFd = -1;

    /** @brief Initialize timerFd related resource */
    void initialize();

    /** @brief The callback function on system time change
     *
     * @param[in] es - Source of the event
     * @param[in] fd - File descriptor of the timer
     * @param[in] revents - Not used
     * @param[in] userdata - User data pointer
     */
    static int onTimeChange(sd_event_source* es, int fd, uint32_t revents,
                            void* userdata);

    /** @brief The deleter of sd_event_source */
    std::function<void(sd_event_source*)> sdEventSourceDeleter =
        [](sd_event_source* p) {
            if (p)
            {
                sd_event_source_unref(p);
            }
        };
    using SdEventSource =
        std::unique_ptr<sd_event_source, decltype(sdEventSourceDeleter)>;

    /** @brief The event source on system time change */
    SdEventSource timeChangeEventSource{nullptr, sdEventSourceDeleter};
};

} // namespace time
} // namespace phosphor