mpd/src/config/Param.hxx
2019-05-29 21:50:04 +02:00

85 lines
2.0 KiB
C++

/*
* Copyright 2003-2018 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef MPD_CONFIG_PARAM_HXX
#define MPD_CONFIG_PARAM_HXX
#include "util/Compiler.h"
#include <string>
class AllocatedPath;
struct ConfigParam {
std::string value;
int line;
explicit ConfigParam(int _line=-1)
:line(_line) {}
template<typename V>
gcc_nonnull_all
explicit ConfigParam(V &&_value, int _line=-1) noexcept
:value(std::forward<V>(_value)), line(_line) {}
ConfigParam(ConfigParam &&) = default;
ConfigParam &operator=(ConfigParam &&) = default;
/**
* Determine if this is a "null" instance, i.e. an empty
* object that was synthesized and not loaded from a
* configuration file.
*/
bool IsNull() const {
return line < 0;
}
/**
* Parse the value as a path. If there is a tilde prefix, it
* is expanded.
*
* Throws #std::runtime_error on error.
*/
AllocatedPath GetPath() const;
/**
* Call this method in a "catch" block to throw a nested
* exception showing the location of this setting in the
* configuration file.
*/
[[noreturn]]
void ThrowWithNested() const;
/**
* Invoke a function with the configured value; if the
* function throws, call ThrowWithNested().
*/
template<typename F>
auto With(F &&f) const {
try {
return f(value.c_str());
} catch (...) {
ThrowWithNested();
}
}
};
#endif