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/*
* This source code is released into the public domain.
*/
module;
#include <iostream>
#include <memory>
#include <optional>
#include <string>
#include <system_error>
#include <variant>
module nihil.error;
import nihil.match;
namespace nihil {
auto to_string(error const &self) -> std::string
{
auto ret = self.str();
auto cause = self.cause();
while (cause) {
ret += ": " + cause->str();
cause = cause->cause();
}
return ret;
}
error::error()
{
}
error::~error() = default;
error::error(std::string_view what, error cause)
: m_error(std::string(what))
, m_cause(std::make_shared<error>(std::move(cause)))
{
}
error::error(std::string_view what)
: m_error(std::string(what))
{
}
error::error(std::error_condition what, error cause)
: m_error(what)
, m_cause(std::make_shared<error>(std::move(cause)))
{
}
error::error(std::error_condition what)
: m_error(what)
{
}
error::error(std::error_code what, error cause)
: m_error(what)
, m_cause(std::make_shared<error>(std::move(cause)))
{
}
error::error(std::error_code what)
: m_error(what)
{
}
error::error(error const &) = default;
error::error(error &&) noexcept = default;
auto error::operator=(this error &, error const &) -> error & = default;
auto error::operator=(this error &, error &&) noexcept -> error & = default;
auto error::cause(this error const &self) -> std::shared_ptr<error>
{
if (self.m_cause)
return self.m_cause;
return {};
}
auto error::root_cause(this error const &self) -> error const &
{
if (self.m_cause)
return self.m_cause->root_cause();
return self;
}
auto error::str(this error const &self) -> std::string
{
return self.m_error | match {
[] (std::monostate) -> std::string {
return "No error";
},
[] (std::error_code const &m) {
return m.message();
},
[] (std::error_condition const &m) {
return m.message();
},
[] (std::string const &m) {
return m;
}
};
}
auto error::code(this error const &self) -> std::optional<std::error_code>
{
auto const *code = std::get_if<std::error_code>(&self.m_error);
if (code)
return {*code};
return {};
}
auto error::condition(this error const &self)
-> std::optional<std::error_condition>
{
auto const *condition = std::get_if<std::error_condition>(&self.m_error);
if (condition)
return {*condition};
return {};
}
auto error::what() const noexcept -> char const *
{
if (!m_what)
m_what = to_string(*this);
return m_what->c_str();
}
auto operator==(error const &lhs, error const &rhs) -> bool
{
return lhs.m_error == rhs.m_error;
}
auto operator<=>(error const &lhs, error const &rhs) -> std::strong_ordering
{
return lhs.m_error <=> rhs.m_error;
}
auto operator==(error const &lhs, std::error_code const &rhs) -> bool
{
return lhs.code() == rhs;
}
// Compare an error to an std::error_condition.
auto operator==(error const &lhs, std::error_condition const &rhs) -> bool
{
return lhs.condition() == rhs;
}
auto operator<<(std::ostream &strm, error const &e) -> std::ostream &
{
return strm << to_string(e);
}
} // namespace nihil
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