ladybird/AK/Error.h
Andreas Kling 4e530135d5 AK+LibSystem+LibMain: Add Error::from_syscall() for syscall failures
This creates an error that contains the name of the syscall that failed.
This allows error handlers to print out the name of the call if they
want to. :^)
2021-11-22 19:28:31 +01:00

147 lines
3.2 KiB
C++

/*
* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Optional.h>
#include <AK/StringView.h>
#include <AK/Try.h>
#if defined(__serenity__) && defined(KERNEL)
# include <LibC/errno_numbers.h>
#else
# include <errno.h>
#endif
namespace AK {
class Error {
public:
static Error from_errno(int code) { return Error(code); }
static Error from_syscall(StringView syscall_name, int rc) { return Error(syscall_name, rc); }
static Error from_string_literal(StringView string_literal) { return Error(string_literal); }
bool is_errno() const { return m_code != 0; }
bool is_syscall() const { return m_syscall; }
int code() const { return m_code; }
StringView string_literal() const { return m_string_literal; }
protected:
Error(int code)
: m_code(code)
{
}
private:
Error(StringView string_literal)
: m_string_literal(string_literal)
{
}
Error(StringView syscall_name, int rc)
: m_code(-rc)
, m_string_literal(syscall_name)
, m_syscall(true)
{
}
int m_code { 0 };
StringView m_string_literal;
bool m_syscall { false };
};
template<typename T, typename ErrorType>
class [[nodiscard]] ErrorOr {
public:
ErrorOr(T const& value)
: m_value(value)
{
}
ErrorOr(T&& value)
: m_value(move(value))
{
}
template<typename U>
ALWAYS_INLINE ErrorOr(U&& value) requires(!IsSame<RemoveCVReference<U>, ErrorOr<T>>)
: m_value(forward<U>(value))
{
}
#ifdef __serenity__
ErrorOr(ErrnoCode code)
: m_error(Error::from_errno(code))
{
}
#endif
ErrorOr(ErrorType&& error)
: m_error(move(error))
{
}
ErrorOr(ErrorOr&& other) = default;
ErrorOr(ErrorOr const& other) = default;
~ErrorOr() = default;
ErrorOr& operator=(ErrorOr&& other) = default;
ErrorOr& operator=(ErrorOr const& other) = default;
T& value() { return m_value.value(); }
Error& error() { return m_error.value(); }
bool is_error() const { return m_error.has_value(); }
T release_value() { return m_value.release_value(); }
ErrorType release_error() { return m_error.release_value(); }
T release_value_but_fixme_should_propagate_errors() { return release_value(); }
private:
Optional<T> m_value;
Optional<ErrorType> m_error;
};
// Partial specialization for void value type
template<typename ErrorType>
class [[nodiscard]] ErrorOr<void, ErrorType> {
public:
ErrorOr(ErrorType error)
: m_error(move(error))
{
}
#ifdef __serenity__
ErrorOr(ErrnoCode code)
: m_error(Error::from_errno(code))
{
}
#endif
ErrorOr() = default;
ErrorOr(ErrorOr&& other) = default;
ErrorOr(ErrorOr const& other) = default;
~ErrorOr() = default;
ErrorOr& operator=(ErrorOr&& other) = default;
ErrorOr& operator=(ErrorOr const& other) = default;
ErrorType& error() { return m_error.value(); }
bool is_error() const { return m_error.has_value(); }
ErrorType release_error() { return m_error.release_value(); }
void release_value() { }
private:
Optional<ErrorType> m_error;
};
}
using AK::Error;
using AK::ErrorOr;