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105 lines
2.3 KiB
C++

// SPDX-License-Identifier: BSD-2-Clause
// Copyright CM4all GmbH
// author: Max Kellermann <mk@cm4all.com>
#pragma once
#include "Chrono.hxx"
#include "event/Features.h"
#include "util/BindMethod.hxx"
#include "util/IntrusiveTreeSet.hxx"
#include <cassert>
class EventLoop;
/**
* This class invokes a callback function after a certain amount of
* time. Use Schedule() to start the timer or Cancel() to cancel it.
*
* Unlike #CoarseTimerEvent, this class uses a high-resolution timer,
* but at the cost of more expensive insertion and deletion.
*
* This class is not thread-safe, all methods must be called from the
* thread that runs the #EventLoop, except where explicitly documented
* as thread-safe.
*/
class FineTimerEvent final :
public IntrusiveTreeSetHook<IntrusiveHookMode::AUTO_UNLINK>
{
friend class TimerList;
EventLoop &loop;
using Callback = BoundMethod<void() noexcept>;
const Callback callback;
/**
* When is this timer due? This is only valid if IsPending()
* returns true.
*/
Event::TimePoint due;
public:
FineTimerEvent(EventLoop &_loop, Callback _callback) noexcept
:loop(_loop), callback(_callback) {}
auto &GetEventLoop() const noexcept {
return loop;
}
constexpr auto GetDue() const noexcept {
return due;
}
/**
* Set the due time as an absolute time point. This can be
* done to prepare an eventual ScheduleCurrent() call. Must
* not be called while the timer is already scheduled.
*/
void SetDue(Event::TimePoint _due) noexcept {
assert(!IsPending());
due = _due;
}
/**
* Set the due time as a duration relative to now. This can
* done to prepare an eventual ScheduleCurrent() call. Must
* not be called while the timer is already scheduled.
*/
void SetDue(Event::Duration d) noexcept;
/**
* Was this timer scheduled?
*/
bool IsPending() const noexcept {
return is_linked();
}
/**
* Schedule the timer at the due time that was already set;
* either by SetDue() or by a Schedule() call that was already
* canceled.
*/
void ScheduleCurrent() noexcept;
void Schedule(Event::Duration d) noexcept;
/**
* Like Schedule(), but is a no-op if there is a due time
* earlier than the given one.
*/
void ScheduleEarlier(Event::Duration d) noexcept;
void Cancel() noexcept {
if (IsPending())
unlink();
}
private:
void Run() noexcept {
callback();
}
};