71f0ed8b74
This eliminates some overhead, because the compiler doesn't need to consider these functions throwing.
84 lines
2.2 KiB
C++
84 lines
2.2 KiB
C++
/*
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* Copyright 2003-2017 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_STATE_FILE_HXX
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#define MPD_STATE_FILE_HXX
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#include "event/TimeoutMonitor.hxx"
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#include "fs/AllocatedPath.hxx"
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#include "Compiler.h"
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#include <string>
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#include <chrono>
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struct Partition;
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class OutputStream;
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class BufferedOutputStream;
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class StateFile final : private TimeoutMonitor {
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const AllocatedPath path;
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const std::string path_utf8;
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const std::chrono::steady_clock::duration interval;
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Partition &partition;
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/**
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* These version numbers determine whether we need to save the state
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* file. If nothing has changed, we won't let the hard drive spin up.
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*/
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unsigned prev_volume_version = 0, prev_output_version = 0,
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prev_playlist_version = 0;
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public:
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static constexpr std::chrono::steady_clock::duration DEFAULT_INTERVAL = std::chrono::minutes(2);
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StateFile(AllocatedPath &&path, std::chrono::steady_clock::duration interval,
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Partition &partition, EventLoop &loop);
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void Read();
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void Write();
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/**
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* Schedules a write if MPD's state was modified.
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*/
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void CheckModified();
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private:
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void Write(OutputStream &os);
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void Write(BufferedOutputStream &os);
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/**
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* Save the current state versions for use with IsModified().
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*/
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void RememberVersions() noexcept;
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/**
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* Check if MPD's state was modified since the last
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* RememberVersions() call.
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*/
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gcc_pure
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bool IsModified() const noexcept;
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/* virtual methods from TimeoutMonitor */
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void OnTimeout() override;
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};
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#endif /* STATE_FILE_H */
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