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/*
** Copyright (C) 2019-2023 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
**
** 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, 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 MU_RESULT_HH__
#define MU_RESULT_HH__
#include <tl/expected.hpp>
#include "utils/mu-error.hh"
namespace Mu {
/**
* A little Rust-envy...a Result is _either_ some value of type T, _or_ a Mu::Error
*/
template <typename T> using Result = tl::expected<T, Error>;
/**
* Ok() is not typically strictly needed (unlike Err), but imitates Rust's Ok
* and it helps the reader.
*
* @param t the value to return
*
* @return a success Result<T>
*/
template <typename T> Result<T>
Ok(T&& t)
{
return std::move(t);
}
/**
* Implementation of Ok() for void results.
*
* @return a success Result<void>
*/
static inline Result<void>
Ok()
{
return {};
}
/**
* Return an error
*
* @param err the error
*
* @return error
*/
template<typename T> Result<T>
Err(Error&& err)
{
return tl::unexpected(std::move(err));
}
template<typename T> Result<T>
Err(const Error& err)
{
return tl::unexpected(err);
}
static inline tl::unexpected<Error>
Err(Error&& err)
{
return tl::unexpected(std::move(err));
}
static inline tl::unexpected<Error>
Err(const Error& err)
{
return tl::unexpected(err);
}
template<typename T>
static inline tl::unexpected<Error>
Err(const Result<T>& res)
{
return res.error();
}
template<typename T>
static inline tl::unexpected<Error>
Err(Result<T>&& res)
{
return std::move(res.error());
}
/*
* convenience
*/
template <typename ...T>
tl::unexpected<Error>
Err(Error::Code code, fmt::format_string<T...> frm, T&&... args)
{
return Err(Error{code, frm, std::forward<T>(args)...});
}
template <typename ...T>
tl::unexpected<Error>
Err(Error::Code code, GError **err, fmt::format_string<T...> frm, T&&... args)
{
return Err(Error{code, err, frm, std::forward<T>(args)...});
}
template<typename T> T
unwrap(Result<T>&& res)
{
if (!!res)
return std::move(res.value());
else
throw res.error();
}
/**
* Assert that some result has a value (for unit tests)
*
* @param R some result
*/
#define assert_valid_result(R) do { \
auto&& res__ = R; \
if(!res__) { \
mu_printerrln("{}:{}: error-result: {}", \
__FILE__, __LINE__, \
(res__).error().what()); \
g_assert_true(!!res__); \
} \
} while(0)
}// namespace Mu
#endif /* MU_RESULT_HH__ */
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