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/***
This file is part of snapcast
Copyright (C) 2014-2024 Johannes Pohl
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 3 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, see <http://www.gnu.org/licenses/>.
***/
#pragma once
// standard headers
#include <optional>
#include <string>
#include <system_error>
#include <variant>
namespace snapcast
{
/// Error codes with detail information
struct ErrorCode : public std::error_code
{
/// c'tor
ErrorCode() : std::error_code(), detail_(std::nullopt)
{
}
/// c'tor
/// @param code the std error code
ErrorCode(const std::error_code& code) : std::error_code(code), detail_(std::nullopt)
{
}
/// c'tor
/// @param code the std error code
/// @param detail additional details
ErrorCode(const std::error_code& code, std::string detail) : std::error_code(code), detail_(std::move(detail))
{
}
/// Move c'tor
ErrorCode(ErrorCode&& other) = default;
/// Move assignment
ErrorCode& operator=(ErrorCode&& rhs) = default;
/// @return detaiöed error message
std::string detailed_message() const
{
if (detail_.has_value())
return message() + ": " + *detail_;
return message();
}
private:
/// Optional error detais
std::optional<std::string> detail_;
};
/// Storage for an ErrorCode or a type T
/// Mostly used as return type
template <class T>
struct ErrorOr
{
/// Move construct with @p t
ErrorOr(T&& t) : var(std::move(t))
{
}
/// Construct with @p t
ErrorOr(const T& t) : var(t)
{
}
/// Move construct with an error
ErrorOr(ErrorCode&& error) : var(std::move(error))
{
}
/// Construct with an error
ErrorOr(const ErrorCode& error) : var(error)
{
}
/// @return true if contains a value (i.e. no error)
bool hasValue()
{
return std::holds_alternative<T>(var);
}
/// @return true if contains an error (i.e. no value)
bool hasError()
{
return std::holds_alternative<ErrorCode>(var);
}
/// @return the value
const T& getValue()
{
return std::get<T>(var);
}
/// @return the moved value
T takeValue()
{
return std::move(std::get<T>(var));
}
/// @return the error
const ErrorCode& getError()
{
return std::get<ErrorCode>(var);
}
/// @return the moved error
ErrorCode takeError()
{
auto ec = std::move(std::get<ErrorCode>(var));
return ec;
}
private:
/// The stored ErrorCode or value
std::variant<ErrorCode, T> var;
};
} // namespace snapcast
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