Files
allwpilib/wpiutil/src/main/native/include/wpi/uv/Timer.h
Peter Johnson ac2f44da33 [wpiutil] uv: use move for std::function (#3653)
Also use function_ref for Loop::Walk().
2021-10-20 23:24:59 -07:00

136 lines
4.0 KiB
C++

// Copyright (c) FIRST and other WPILib contributors.
// Open Source Software; you can modify and/or share it under the terms of
// the WPILib BSD license file in the root directory of this project.
#ifndef WPIUTIL_WPI_UV_TIMER_H_
#define WPIUTIL_WPI_UV_TIMER_H_
#include <uv.h>
#include <chrono>
#include <functional>
#include <memory>
#include <utility>
#include "wpi/Signal.h"
#include "wpi/uv/Handle.h"
namespace wpi::uv {
class Loop;
/**
* Timer handle.
* Timer handles are used to schedule signals to be called in the future.
*/
class Timer final : public HandleImpl<Timer, uv_timer_t> {
struct private_init {};
public:
using Time = std::chrono::duration<uint64_t, std::milli>;
explicit Timer(const private_init&) {}
~Timer() noexcept override = default;
/**
* Create a timer handle.
*
* @param loop Loop object where this handle runs.
*/
static std::shared_ptr<Timer> Create(Loop& loop);
/**
* Create a timer handle.
*
* @param loop Loop object where this handle runs.
*/
static std::shared_ptr<Timer> Create(const std::shared_ptr<Loop>& loop) {
return Create(*loop);
}
/**
* Create a timer that calls a functor after a given time interval.
*
* @param loop Loop object where the timer should run.
* @param timeout Time interval
* @param func Functor
*/
static void SingleShot(Loop& loop, Time timeout, std::function<void()> func);
/**
* Create a timer that calls a functor after a given time interval.
*
* @param loop Loop object where the timer should run.
* @param timeout Time interval
* @param func Functor
*/
static void SingleShot(const std::shared_ptr<Loop>& loop, Time timeout,
std::function<void()> func) {
return SingleShot(*loop, timeout, std::move(func));
}
/**
* Start the timer.
*
* If timeout is zero, an event is emitted on the next event loop
* iteration. If repeat is non-zero, an event is emitted first
* after timeout milliseconds and then repeatedly after repeat milliseconds.
*
* @param timeout Milliseconds before to emit an event (use
* `std::chrono::duration<uint64_t, std::milli>`).
* @param repeat Milliseconds between successive events (use
* `std::chrono::duration<uint64_t, std::milli>`).
*/
void Start(Time timeout, Time repeat = Time{0});
/**
* Stop the timer.
*/
void Stop() { Invoke(&uv_timer_stop, GetRaw()); }
/**
* Stop the timer and restart it if it was repeating.
*
* Stop the timer, and if it is repeating restart it using the repeat value
* as the timeout.
* If the timer has never been started before it emits sigError.
*/
void Again() { Invoke(&uv_timer_again, GetRaw()); }
/**
* Set the repeat interval value.
*
* The timer will be scheduled to run on the given interval and will follow
* normal timer semantics in the case of a time-slice overrun.
* For example, if a 50ms repeating timer first runs for 17ms, it will be
* scheduled to run again 33ms later. If other tasks consume more than the
* 33ms following the first timer event, then another event will be emitted
* as soon as possible.
*
* If the repeat value is set from a listener bound to an event, it does
* not immediately take effect. If the timer was non-repeating before, it
* will have been stopped. If it was repeating, then the old repeat value
* will have been used to schedule the next timeout.
*
* @param repeat Repeat interval in milliseconds (use
* `std::chrono::duration<uint64_t, std::milli>`).
*/
void SetRepeat(Time repeat) { uv_timer_set_repeat(GetRaw(), repeat.count()); }
/**
* Get the timer repeat value.
* @return Timer repeat value in milliseconds (as a
* `std::chrono::duration<uint64_t, std::milli>`).
*/
Time GetRepeat() const { return Time{uv_timer_get_repeat(GetRaw())}; }
/**
* Signal generated when the timeout event occurs.
*/
sig::Signal<> timeout;
};
} // namespace wpi::uv
#endif // WPIUTIL_WPI_UV_TIMER_H_