/usr/include/mircore/mir/optional_value.h is in libmircore-dev 0.26.3+16.04.20170605-0ubuntu1.1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 | /*
* Copyright © 2014 Canonical Ltd.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License version 3 as
* published by the Free Software Foundation.
*
* 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Authored by: Alberto Aguirre <alberto.aguirre@canonical.com>
*/
#ifndef MIR_OPTIONAL_VALUE_H_
#define MIR_OPTIONAL_VALUE_H_
#include "mir/fatal.h"
#include <utility>
namespace mir
{
template<typename T>
class optional_value
{
public:
optional_value() = default;
optional_value(T const& value) : value_(value), is_set_{true} {}
optional_value& operator=(T const& value)
{
value_ = value;
is_set_ = true;
return *this;
}
bool is_set() const { return is_set_; }
T const& value() const
{
die_if_unset();
return value_;
}
T& value()
{
die_if_unset();
return value_;
}
T&& consume()
{
die_if_unset();
is_set_ = false;
return std::move(value_);
}
private:
void die_if_unset() const
{
if (!is_set())
{
(*fatal_error)("Accessing value of unset optional");
}
}
T value_;
bool is_set_{false};
};
template<typename T>
inline bool operator == (optional_value<T> const& lhs, optional_value<T> const& rhs)
{
return lhs.is_set() == rhs.is_set() &&
(!lhs.is_set() || lhs.value() == rhs.value());
}
template<typename T>
inline bool operator != (optional_value<T> const& lhs, optional_value<T> const& rhs)
{
return !(lhs == rhs);
}
template<typename T>
inline bool operator == (optional_value<T> const& lhs, T const& rhs)
{
return lhs.is_set() && (lhs.value() == rhs);
}
template<typename T>
inline bool operator != (optional_value<T> const& lhs, T const& rhs)
{
return !(lhs == rhs);
}
template<typename T>
inline bool operator == (T const& lhs, optional_value<T> const& rhs)
{
return rhs == lhs;
}
template<typename T>
inline bool operator != (T const& lhs, optional_value<T> const& rhs)
{
return rhs != lhs;
}
}
#endif /* MIR_OPTIONAL_VALUE_H_ */
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