81 lines
2.0 KiB
C++
81 lines
2.0 KiB
C++
/*
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* Copyright 2003-2021 The Music Player Daemon Project
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* http://www.musicpd.org
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef MPD_DEFER_EVENT_HXX
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#define MPD_DEFER_EVENT_HXX
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#include "util/BindMethod.hxx"
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#include "util/IntrusiveList.hxx"
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class EventLoop;
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/**
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* Defer execution until the next event loop iteration. Use this to
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* move calls out of the current stack frame, to avoid surprising side
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* effects for callers up in the call chain.
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*
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* This class is not thread-safe, all methods must be called from the
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* thread that runs the #EventLoop.
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*/
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class DeferEvent final : AutoUnlinkIntrusiveListHook
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{
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friend class EventLoop;
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friend class IntrusiveList<DeferEvent>;
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EventLoop &loop;
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using Callback = BoundMethod<void() noexcept>;
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const Callback callback;
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public:
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DeferEvent(EventLoop &_loop, Callback _callback) noexcept
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:loop(_loop), callback(_callback) {}
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DeferEvent(const DeferEvent &) = delete;
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DeferEvent &operator=(const DeferEvent &) = delete;
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auto &GetEventLoop() const noexcept {
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return loop;
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}
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bool IsPending() const noexcept {
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return is_linked();
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}
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void Schedule() noexcept;
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/**
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* Schedule this event, but only after the #EventLoop is idle,
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* i.e. before going to sleep.
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*/
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void ScheduleIdle() noexcept;
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void Cancel() noexcept {
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if (IsPending())
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unlink();
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}
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private:
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void Run() noexcept {
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callback();
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}
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};
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#endif
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