mpd/src/event/FineTimerEvent.hxx

117 lines
3.1 KiB
C++

/*
* Copyright 2007-2021 CM4all GmbH
* All rights reserved.
*
* author: Max Kellermann <mk@cm4all.com>
*
* 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.
*
* 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
* FOUNDATION 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.
*/
#pragma once
#include "Chrono.hxx"
#include "event/Features.h"
#include "util/BindMethod.hxx"
#ifdef NO_BOOST
#include "util/IntrusiveList.hxx"
#else
#include <boost/intrusive/set_hook.hpp>
#endif
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 :
#ifdef NO_BOOST
AutoUnlinkIntrusiveListHook
#else
public boost::intrusive::set_base_hook<boost::intrusive::link_mode<boost::intrusive::auto_unlink>>
#endif
{
friend class TimerList;
#ifdef NO_BOOST
friend class IntrusiveList<FineTimerEvent>;
#endif
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;
}
bool IsPending() const noexcept {
return is_linked();
}
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 {
#ifdef NO_BOOST
if (IsPending())
#endif
unlink();
}
private:
void Run() noexcept {
callback();
}
};