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Kernel: Replace KResult and KResultOr<T> with Error and ErrorOr<T>

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We now use AK::Error and AK::ErrorOr<T> in both kernel and userspace!
This was a slightly tedious refactoring that took a long time, so it's
not unlikely that some bugs crept in.

Nevertheless, it does pass basic functionality testing, and it's just
real nice to finally see the same pattern in all contexts. :^)
This commit is contained in:
Andreas Kling 2021-11-08 00:51:39 +01:00
parent 7ee10c6926
commit 79fa9765ca
262 changed files with 2415 additions and 2600 deletions
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199
Kernel/API/KResult.h
View file

@ -1,199 +0,0 @@
/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Assertions.h>
#include <AK/Format.h>
#include <AK/Platform.h>
#include <AK/StdLibExtras.h>
#include <AK/Try.h>
#include <LibC/errno_numbers.h>
namespace Kernel {
enum KSuccessTag {
KSuccess
};
class [[nodiscard]] KResult {
public:
KResult(ErrnoCode error)
: m_error(-error)
{
}
KResult(KSuccessTag)
: m_error(0)
{
}
[[nodiscard]] int error() const { return m_error; }
[[nodiscard]] bool is_success() const { return m_error == 0; }
[[nodiscard]] bool is_error() const { return !is_success(); }
bool operator==(ErrnoCode error) const { return is_error() && m_error == -error; }
bool operator!=(ErrnoCode error) const { return !is_error() || m_error != -error; }
bool operator!=(KSuccessTag) const { return is_error(); }
bool operator==(KSuccessTag) const { return !is_error(); }
// NOTE: These are here to make KResult usable with TRY()
KResult release_error() { return *this; }
void release_value() { }
private:
template<typename T>
friend class KResultOr;
KResult() = default;
int m_error { 0 };
};
template<typename T>
class [[nodiscard]] KResultOr {
public:
KResultOr(KResult error)
: m_error(error)
, m_is_error(true)
{
}
KResultOr(ErrnoCode error)
: m_error(error)
, m_is_error(true)
{
}
ALWAYS_INLINE KResultOr(T&& value)
: m_have_storage(true)
{
new (&m_storage) T(move(value));
}
ALWAYS_INLINE KResultOr(const T& value)
: m_have_storage(true)
{
new (&m_storage) T(value);
}
template<typename U>
ALWAYS_INLINE KResultOr(U&& value) requires(!IsSame<RemoveCVReference<U>, KResultOr<T>>)
: m_have_storage(true)
{
new (&m_storage) T(forward<U>(value));
}
KResultOr(KResultOr&& other)
{
m_is_error = other.m_is_error;
if (m_is_error) {
m_error = other.m_error;
} else {
if (other.m_have_storage) {
new (&m_storage) T(move(other.value()));
m_have_storage = true;
other.value().~T();
other.m_have_storage = false;
}
}
other.m_is_error = true;
other.m_error = KSuccess;
}
KResultOr& operator=(KResultOr&& other)
{
if (&other == this)
return *this;
if (!m_is_error && m_have_storage) {
value().~T();
m_have_storage = false;
}
m_is_error = other.m_is_error;
if (m_is_error) {
m_error = other.m_error;
} else {
if (other.m_have_storage) {
new (&m_storage) T(move(other.value()));
m_have_storage = true;
other.value().~T();
other.m_have_storage = false;
}
}
other.m_is_error = true;
other.m_error = KSuccess;
return *this;
}
~KResultOr()
{
if (!m_is_error && m_have_storage)
value().~T();
}
[[nodiscard]] bool is_error() const { return m_is_error; }
[[nodiscard]] ALWAYS_INLINE KResult error() const
{
VERIFY(m_is_error);
return m_error;
}
KResult result() const { return m_is_error ? m_error : KSuccess; }
[[nodiscard]] ALWAYS_INLINE T& value() &
{
VERIFY(!m_is_error);
return *reinterpret_cast<T*>(&m_storage);
}
[[nodiscard]] ALWAYS_INLINE T const& value() const&
{
VERIFY(!m_is_error);
return *reinterpret_cast<T*>(&m_storage);
}
T value() && = delete;
[[nodiscard]] ALWAYS_INLINE T release_value()
{
VERIFY(!m_is_error);
VERIFY(m_have_storage);
T released_value(move(*reinterpret_cast<T*>(&m_storage)));
value().~T();
m_have_storage = false;
return released_value;
}
KResult release_error()
{
VERIFY(m_is_error);
return m_error;
}
private:
union {
alignas(T) char m_storage[sizeof(T)];
KResult m_error;
};
bool m_is_error { false };
bool m_have_storage { false };
};
}
using Kernel::KResult;
using Kernel::KResultOr;
using Kernel::KSuccess;
template<>
struct AK::Formatter<KResult> : Formatter<FormatString> {
void format(FormatBuilder& builder, Kernel::KResult value)
{
if (value.is_error())
return AK::Formatter<FormatString>::format(builder, "KResult({})", value.error());
return AK::Formatter<FormatString>::format(builder, "KResult(success)");
}
};