2021-11-06 03:18:43 +03:00
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/*
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* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/StringView.h>
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2021-11-08 02:35:58 +03:00
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#include <AK/Try.h>
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2021-12-15 01:02:23 +03:00
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#include <AK/Variant.h>
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2021-11-06 03:18:43 +03:00
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2022-10-10 00:23:23 +03:00
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#if defined(AK_OS_SERENITY) && defined(KERNEL)
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2021-09-12 14:29:28 +03:00
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# include <LibC/errno_codes.h>
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2021-11-06 03:18:43 +03:00
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#else
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# include <errno.h>
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2021-12-20 13:55:32 +03:00
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# include <string.h>
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2021-11-06 03:18:43 +03:00
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#endif
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namespace AK {
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class Error {
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public:
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static Error from_errno(int code) { return Error(code); }
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2021-11-22 18:00:53 +03:00
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static Error from_syscall(StringView syscall_name, int rc) { return Error(syscall_name, rc); }
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2022-07-11 20:57:32 +03:00
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static Error from_string_view(StringView string_literal) { return Error(string_literal); }
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// NOTE: Prefer `from_string_literal` when directly typing out an error message:
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//
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// return Error::from_string_literal("Class: Some failure");
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//
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// If you need to return a static string based on a dynamic condition (like
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// picking an error from an array), then prefer `from_string_view` instead.
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template<size_t N>
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ALWAYS_INLINE static Error from_string_literal(char const (&string_literal)[N])
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{
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return from_string_view(StringView { string_literal, N - 1 });
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}
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2022-06-08 16:56:21 +03:00
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bool operator==(Error const& other) const
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{
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return m_code == other.m_code && m_string_literal == other.m_string_literal && m_syscall == other.m_syscall;
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}
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bool is_errno() const { return m_code != 0; }
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bool is_syscall() const { return m_syscall; }
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int code() const { return m_code; }
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StringView string_literal() const { return m_string_literal; }
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protected:
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Error(int code)
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: m_code(code)
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{
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}
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private:
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Error(StringView string_literal)
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: m_string_literal(string_literal)
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{
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}
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2021-11-22 18:00:53 +03:00
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Error(StringView syscall_name, int rc)
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: m_code(-rc)
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, m_string_literal(syscall_name)
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, m_syscall(true)
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{
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}
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int m_code { 0 };
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StringView m_string_literal;
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bool m_syscall { false };
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};
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2022-12-10 14:59:20 +03:00
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template<typename T, typename E>
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class [[nodiscard]] ErrorOr {
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public:
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using ResultType = T;
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using ErrorType = E;
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2022-10-17 01:06:11 +03:00
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ErrorOr()
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requires(IsSame<T, Empty>)
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: m_value_or_error(Empty {})
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{
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}
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2022-12-09 19:38:09 +03:00
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ALWAYS_INLINE ErrorOr(ErrorOr&&) = default;
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ALWAYS_INLINE ErrorOr(ErrorOr const&) = default;
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ALWAYS_INLINE ErrorOr& operator=(ErrorOr&&) = default;
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ALWAYS_INLINE ErrorOr& operator=(ErrorOr const&) = default;
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template<typename U>
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ALWAYS_INLINE ErrorOr(ErrorOr<U, ErrorType> const& value)
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: m_value_or_error(value.m_value_or_error.visit([](U const& v) -> Variant<T, ErrorType> { return v; }, [](ErrorType const& error) -> Variant<T, ErrorType> { return error; }))
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{
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}
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template<typename U>
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ALWAYS_INLINE ErrorOr(ErrorOr<U, ErrorType>& value)
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: m_value_or_error(value.m_value_or_error.visit([](U& v) { return Variant<T, ErrorType>(move(v)); }, [](ErrorType& error) { return Variant<T, ErrorType>(move(error)); }))
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{
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}
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template<typename U>
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ALWAYS_INLINE ErrorOr(ErrorOr<U, ErrorType>&& value)
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: m_value_or_error(value.visit([](U& v) { return Variant<T, ErrorType>(move(v)); }, [](ErrorType& error) { return Variant<T, ErrorType>(move(error)); }))
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{
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}
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template<typename U>
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ALWAYS_INLINE ErrorOr(U&& value)
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requires(
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requires { T(declval<U>()); } || requires { ErrorType(declval<RemoveCVReference<U>>()); })
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: m_value_or_error(forward<U>(value))
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{
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}
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2022-10-10 00:23:23 +03:00
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#ifdef AK_OS_SERENITY
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ErrorOr(ErrnoCode code)
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: m_value_or_error(Error::from_errno(code))
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{
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}
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#endif
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T& value()
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{
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return m_value_or_error.template get<T>();
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}
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T const& value() const { return m_value_or_error.template get<T>(); }
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ErrorType& error() { return m_value_or_error.template get<ErrorType>(); }
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ErrorType const& error() const { return m_value_or_error.template get<ErrorType>(); }
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bool is_error() const { return m_value_or_error.template has<ErrorType>(); }
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T release_value() { return move(value()); }
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ErrorType release_error() { return move(error()); }
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2022-02-06 15:49:51 +03:00
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T release_value_but_fixme_should_propagate_errors()
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{
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VERIFY(!is_error());
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return release_value();
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}
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2021-11-06 13:29:32 +03:00
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2021-11-06 03:18:43 +03:00
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private:
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Variant<T, ErrorType> m_value_or_error;
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};
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2021-11-07 03:30:35 +03:00
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template<typename ErrorType>
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class [[nodiscard]] ErrorOr<void, ErrorType> : public ErrorOr<Empty, ErrorType> {
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public:
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using ResultType = void;
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using ErrorOr<Empty, ErrorType>::ErrorOr;
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};
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}
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2022-11-26 14:18:30 +03:00
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#if USING_AK_GLOBALLY
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2021-11-06 12:34:14 +03:00
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using AK::Error;
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using AK::ErrorOr;
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#endif
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