mirror of
https://github.com/LadybirdBrowser/ladybird.git
synced 2024-11-08 23:42:53 +03:00
00b4976f2c
GCC 13 was released on 2023-04-26. This commit fixes Lagom build errors when using an updated host toolchain: - Adds a workaround for a bug in constraint handling, which made LibJS fail to compile: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109683 - Silences the new `-Wdangling-reference` diagnostic globally. It produces multiple false positives with no clear way to silence them without `#pragmas`. - Silences `-Wself-move` in `RefPtr` tests as GCC 13 adds this previously Clang-exclusive warning.
540 lines
18 KiB
C++
540 lines
18 KiB
C++
/*
|
|
* Copyright (c) 2021, Ali Mohammad Pur <mpfard@serenityos.org>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <AK/Array.h>
|
|
#include <AK/BitCast.h>
|
|
#include <AK/StdLibExtras.h>
|
|
#include <AK/TypeList.h>
|
|
|
|
namespace AK::Detail {
|
|
|
|
template<typename T, typename IndexType, IndexType InitialIndex, typename... InTypes>
|
|
struct VariantIndexOf {
|
|
static_assert(DependentFalse<T, IndexType, InTypes...>, "Invalid VariantIndex instantiated");
|
|
};
|
|
|
|
template<typename T, typename IndexType, IndexType InitialIndex, typename InType, typename... RestOfInTypes>
|
|
struct VariantIndexOf<T, IndexType, InitialIndex, InType, RestOfInTypes...> {
|
|
consteval IndexType operator()()
|
|
{
|
|
if constexpr (IsSame<T, InType>)
|
|
return InitialIndex;
|
|
else
|
|
return VariantIndexOf<T, IndexType, InitialIndex + 1, RestOfInTypes...> {}();
|
|
}
|
|
};
|
|
|
|
template<typename T, typename IndexType, IndexType InitialIndex>
|
|
struct VariantIndexOf<T, IndexType, InitialIndex> {
|
|
consteval IndexType operator()() { return InitialIndex; }
|
|
};
|
|
|
|
template<typename T, typename IndexType, typename... Ts>
|
|
consteval IndexType index_of()
|
|
{
|
|
return VariantIndexOf<T, IndexType, 0, Ts...> {}();
|
|
}
|
|
|
|
template<typename IndexType, IndexType InitialIndex, typename... Ts>
|
|
struct Variant;
|
|
|
|
template<typename IndexType, IndexType InitialIndex, typename F, typename... Ts>
|
|
struct Variant<IndexType, InitialIndex, F, Ts...> {
|
|
static constexpr auto current_index = VariantIndexOf<F, IndexType, InitialIndex, F, Ts...> {}();
|
|
ALWAYS_INLINE static void delete_(IndexType id, void* data)
|
|
{
|
|
if (id == current_index)
|
|
bit_cast<F*>(data)->~F();
|
|
else
|
|
Variant<IndexType, InitialIndex + 1, Ts...>::delete_(id, data);
|
|
}
|
|
|
|
ALWAYS_INLINE static void move_(IndexType old_id, void* old_data, void* new_data)
|
|
{
|
|
if (old_id == current_index)
|
|
new (new_data) F(move(*bit_cast<F*>(old_data)));
|
|
else
|
|
Variant<IndexType, InitialIndex + 1, Ts...>::move_(old_id, old_data, new_data);
|
|
}
|
|
|
|
ALWAYS_INLINE static void copy_(IndexType old_id, void const* old_data, void* new_data)
|
|
{
|
|
if (old_id == current_index)
|
|
new (new_data) F(*bit_cast<F const*>(old_data));
|
|
else
|
|
Variant<IndexType, InitialIndex + 1, Ts...>::copy_(old_id, old_data, new_data);
|
|
}
|
|
};
|
|
|
|
template<typename IndexType, IndexType InitialIndex>
|
|
struct Variant<IndexType, InitialIndex> {
|
|
ALWAYS_INLINE static void delete_(IndexType, void*) { }
|
|
ALWAYS_INLINE static void move_(IndexType, void*, void*) { }
|
|
ALWAYS_INLINE static void copy_(IndexType, void const*, void*) { }
|
|
};
|
|
|
|
template<typename IndexType, typename... Ts>
|
|
struct VisitImpl {
|
|
template<typename RT, typename T, size_t I, typename Fn>
|
|
static constexpr bool has_explicitly_named_overload()
|
|
{
|
|
// If we're not allowed to make a member function pointer and call it directly (without explicitly resolving it),
|
|
// we have a templated function on our hands (or a function overload set).
|
|
// in such cases, we don't have an explicitly named overload, and we would have to select it.
|
|
return requires { (declval<Fn>().*(&Fn::operator()))(declval<T>()); };
|
|
}
|
|
|
|
template<typename ReturnType, typename T, typename Visitor, auto... Is>
|
|
static constexpr bool should_invoke_const_overload(IndexSequence<Is...>)
|
|
{
|
|
// Scan over all the different visitor functions, if none of them are suitable for calling with `T const&`, avoid calling that first.
|
|
return ((has_explicitly_named_overload<ReturnType, T, Is, typename Visitor::Types::template Type<Is>>()) || ...);
|
|
}
|
|
|
|
template<typename Self, typename Visitor, IndexType CurrentIndex = 0>
|
|
ALWAYS_INLINE static constexpr decltype(auto) visit(Self& self, IndexType id, void const* data, Visitor&& visitor)
|
|
requires(CurrentIndex < sizeof...(Ts))
|
|
{
|
|
using T = typename TypeList<Ts...>::template Type<CurrentIndex>;
|
|
|
|
if (id == CurrentIndex) {
|
|
// Check if Visitor::operator() is an explicitly typed function (as opposed to a templated function)
|
|
// if so, try to call that with `T const&` first before copying the Variant's const-ness.
|
|
// This emulates normal C++ call semantics where templated functions are considered last, after all non-templated overloads
|
|
// are checked and found to be unusable.
|
|
using ReturnType = decltype(visitor(*bit_cast<T*>(data)));
|
|
if constexpr (should_invoke_const_overload<ReturnType, T, Visitor>(MakeIndexSequence<Visitor::Types::size>()))
|
|
return visitor(*bit_cast<AddConst<T>*>(data));
|
|
|
|
return visitor(*bit_cast<CopyConst<Self, T>*>(data));
|
|
}
|
|
|
|
if constexpr ((CurrentIndex + 1) < sizeof...(Ts))
|
|
return visit<Self, Visitor, CurrentIndex + 1>(self, id, data, forward<Visitor>(visitor));
|
|
else
|
|
VERIFY_NOT_REACHED();
|
|
}
|
|
};
|
|
|
|
struct VariantNoClearTag {
|
|
explicit VariantNoClearTag() = default;
|
|
};
|
|
struct VariantConstructTag {
|
|
explicit VariantConstructTag() = default;
|
|
};
|
|
|
|
template<typename T, typename Base>
|
|
struct VariantConstructors {
|
|
// The pointless `typename Base` constraints are a workaround for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109683
|
|
ALWAYS_INLINE VariantConstructors(T&& t)
|
|
requires(requires { T(move(t)); typename Base; })
|
|
{
|
|
internal_cast().clear_without_destruction();
|
|
internal_cast().set(move(t), VariantNoClearTag {});
|
|
}
|
|
|
|
ALWAYS_INLINE VariantConstructors(T const& t)
|
|
requires(requires { T(t); typename Base; })
|
|
{
|
|
internal_cast().clear_without_destruction();
|
|
internal_cast().set(t, VariantNoClearTag {});
|
|
}
|
|
|
|
ALWAYS_INLINE VariantConstructors() = default;
|
|
|
|
private:
|
|
[[nodiscard]] ALWAYS_INLINE Base& internal_cast()
|
|
{
|
|
// Warning: Internal type shenanigans - VariantsConstrutors<T, Base> <- Base
|
|
// Not the other way around, so be _really_ careful not to cause issues.
|
|
return *static_cast<Base*>(this);
|
|
}
|
|
};
|
|
|
|
// Type list deduplication
|
|
// Since this is a big template mess, each template is commented with how and why it works.
|
|
struct ParameterPackTag {
|
|
};
|
|
|
|
// Pack<Ts...> is just a way to pass around the type parameter pack Ts
|
|
template<typename... Ts>
|
|
struct ParameterPack : ParameterPackTag {
|
|
};
|
|
|
|
// Blank<T> is a unique replacement for T, if T is a duplicate type.
|
|
template<typename T>
|
|
struct Blank {
|
|
};
|
|
|
|
template<typename A, typename P>
|
|
inline constexpr bool IsTypeInPack = false;
|
|
|
|
// IsTypeInPack<T, Pack<Ts...>> will just return whether 'T' exists in 'Ts'.
|
|
template<typename T, typename... Ts>
|
|
inline constexpr bool IsTypeInPack<T, ParameterPack<Ts...>> = (IsSame<T, Ts> || ...);
|
|
|
|
// Replaces T with Blank<T> if it exists in Qs.
|
|
template<typename T, typename... Qs>
|
|
using BlankIfDuplicate = Conditional<(IsTypeInPack<T, Qs> || ...), Blank<T>, T>;
|
|
|
|
template<unsigned I, typename...>
|
|
struct InheritFromUniqueEntries;
|
|
|
|
// InheritFromUniqueEntries will inherit from both Qs and Ts, but only scan entries going *forwards*
|
|
// that is to say, if it's scanning from index I in Qs, it won't scan for duplicates for entries before I
|
|
// as that has already been checked before.
|
|
// This makes sure that the search is linear in time (like the 'merge' step of merge sort).
|
|
template<unsigned I, typename... Ts, unsigned... Js, typename... Qs>
|
|
struct InheritFromUniqueEntries<I, ParameterPack<Ts...>, IndexSequence<Js...>, Qs...>
|
|
: public BlankIfDuplicate<Ts, Conditional<Js <= I, ParameterPack<>, Qs>...>... {
|
|
|
|
using BlankIfDuplicate<Ts, Conditional<Js <= I, ParameterPack<>, Qs>...>::BlankIfDuplicate...;
|
|
};
|
|
|
|
template<typename...>
|
|
struct InheritFromPacks;
|
|
|
|
// InheritFromPacks will attempt to 'merge' the pack 'Ps' with *itself*, but skip the duplicate entries
|
|
// (via InheritFromUniqueEntries).
|
|
template<unsigned... Is, typename... Ps>
|
|
struct InheritFromPacks<IndexSequence<Is...>, Ps...>
|
|
: public InheritFromUniqueEntries<Is, Ps, IndexSequence<Is...>, Ps...>... {
|
|
|
|
using InheritFromUniqueEntries<Is, Ps, IndexSequence<Is...>, Ps...>::InheritFromUniqueEntries...;
|
|
};
|
|
|
|
// Just a nice wrapper around InheritFromPacks, which will wrap any parameter packs in ParameterPack (unless it already is one).
|
|
template<typename... Ps>
|
|
using MergeAndDeduplicatePacks = InheritFromPacks<MakeIndexSequence<sizeof...(Ps)>, Conditional<IsBaseOf<ParameterPackTag, Ps>, Ps, ParameterPack<Ps>>...>;
|
|
|
|
}
|
|
|
|
namespace AK {
|
|
|
|
struct Empty {
|
|
};
|
|
|
|
template<typename T>
|
|
concept NotLvalueReference = !
|
|
IsLvalueReference<T>;
|
|
|
|
template<NotLvalueReference... Ts>
|
|
struct Variant
|
|
: public Detail::MergeAndDeduplicatePacks<Detail::VariantConstructors<Ts, Variant<Ts...>>...> {
|
|
public:
|
|
using IndexType = Conditional<(sizeof...(Ts) < 255), u8, size_t>; // Note: size+1 reserved for internal value checks
|
|
private:
|
|
static constexpr IndexType invalid_index = sizeof...(Ts);
|
|
|
|
template<typename T>
|
|
static constexpr IndexType index_of() { return Detail::index_of<T, IndexType, Ts...>(); }
|
|
|
|
public:
|
|
template<typename T>
|
|
static constexpr bool can_contain()
|
|
{
|
|
return index_of<T>() != invalid_index;
|
|
}
|
|
|
|
template<typename... NewTs>
|
|
Variant(Variant<NewTs...>&& old)
|
|
requires((can_contain<NewTs>() && ...))
|
|
: Variant(move(old).template downcast<Ts...>())
|
|
{
|
|
}
|
|
|
|
template<typename... NewTs>
|
|
Variant(Variant<NewTs...> const& old)
|
|
requires((can_contain<NewTs>() && ...))
|
|
: Variant(old.template downcast<Ts...>())
|
|
{
|
|
}
|
|
|
|
template<NotLvalueReference... NewTs>
|
|
friend struct Variant;
|
|
|
|
Variant()
|
|
requires(!can_contain<Empty>())
|
|
= delete;
|
|
Variant()
|
|
requires(can_contain<Empty>())
|
|
: Variant(Empty())
|
|
{
|
|
}
|
|
|
|
#ifdef AK_HAS_CONDITIONALLY_TRIVIAL
|
|
Variant(Variant const&)
|
|
requires(!(IsCopyConstructible<Ts> && ...))
|
|
= delete;
|
|
Variant(Variant const&) = default;
|
|
|
|
Variant(Variant&&)
|
|
requires(!(IsMoveConstructible<Ts> && ...))
|
|
= delete;
|
|
Variant(Variant&&) = default;
|
|
|
|
~Variant()
|
|
requires(!(IsDestructible<Ts> && ...))
|
|
= delete;
|
|
~Variant() = default;
|
|
|
|
Variant& operator=(Variant const&)
|
|
requires(!(IsCopyConstructible<Ts> && ...) || !(IsDestructible<Ts> && ...))
|
|
= delete;
|
|
Variant& operator=(Variant const&) = default;
|
|
|
|
Variant& operator=(Variant&&)
|
|
requires(!(IsMoveConstructible<Ts> && ...) || !(IsDestructible<Ts> && ...))
|
|
= delete;
|
|
Variant& operator=(Variant&&) = default;
|
|
#endif
|
|
|
|
ALWAYS_INLINE Variant(Variant const& old)
|
|
#ifdef AK_HAS_CONDITIONALLY_TRIVIAL
|
|
requires(!(IsTriviallyCopyConstructible<Ts> && ...))
|
|
#endif
|
|
: Detail::MergeAndDeduplicatePacks<Detail::VariantConstructors<Ts, Variant<Ts...>>...>()
|
|
, m_data {}
|
|
, m_index(old.m_index)
|
|
{
|
|
Helper::copy_(old.m_index, old.m_data, m_data);
|
|
}
|
|
|
|
// Note: A moved-from variant emulates the state of the object it contains
|
|
// so if a variant containing an int is moved from, it will still contain that int
|
|
// and if a variant with a nontrivial move ctor is moved from, it may or may not be valid
|
|
// but it will still contain the "moved-from" state of the object it previously contained.
|
|
ALWAYS_INLINE Variant(Variant&& old)
|
|
#ifdef AK_HAS_CONDITIONALLY_TRIVIAL
|
|
requires(!(IsTriviallyMoveConstructible<Ts> && ...))
|
|
#endif
|
|
: Detail::MergeAndDeduplicatePacks<Detail::VariantConstructors<Ts, Variant<Ts...>>...>()
|
|
, m_index(old.m_index)
|
|
{
|
|
Helper::move_(old.m_index, old.m_data, m_data);
|
|
}
|
|
|
|
ALWAYS_INLINE ~Variant()
|
|
#ifdef AK_HAS_CONDITIONALLY_TRIVIAL
|
|
requires(!(IsTriviallyDestructible<Ts> && ...))
|
|
#endif
|
|
{
|
|
Helper::delete_(m_index, m_data);
|
|
}
|
|
|
|
ALWAYS_INLINE Variant& operator=(Variant const& other)
|
|
#ifdef AK_HAS_CONDITIONALLY_TRIVIAL
|
|
requires(!(IsTriviallyCopyConstructible<Ts> && ...) || !(IsTriviallyDestructible<Ts> && ...))
|
|
#endif
|
|
{
|
|
if (this != &other) {
|
|
if constexpr (!(IsTriviallyDestructible<Ts> && ...)) {
|
|
Helper::delete_(m_index, m_data);
|
|
}
|
|
m_index = other.m_index;
|
|
Helper::copy_(other.m_index, other.m_data, m_data);
|
|
}
|
|
return *this;
|
|
}
|
|
|
|
ALWAYS_INLINE Variant& operator=(Variant&& other)
|
|
#ifdef AK_HAS_CONDITIONALLY_TRIVIAL
|
|
requires(!(IsTriviallyMoveConstructible<Ts> && ...) || !(IsTriviallyDestructible<Ts> && ...))
|
|
#endif
|
|
{
|
|
if (this != &other) {
|
|
if constexpr (!(IsTriviallyDestructible<Ts> && ...)) {
|
|
Helper::delete_(m_index, m_data);
|
|
}
|
|
m_index = other.m_index;
|
|
Helper::move_(other.m_index, other.m_data, m_data);
|
|
}
|
|
return *this;
|
|
}
|
|
|
|
using Detail::MergeAndDeduplicatePacks<Detail::VariantConstructors<Ts, Variant<Ts...>>...>::MergeAndDeduplicatePacks;
|
|
|
|
template<typename T, typename StrippedT = RemoveCVReference<T>>
|
|
void set(T&& t)
|
|
requires(can_contain<StrippedT>() && requires { StrippedT(forward<T>(t)); })
|
|
{
|
|
constexpr auto new_index = index_of<StrippedT>();
|
|
Helper::delete_(m_index, m_data);
|
|
new (m_data) StrippedT(forward<T>(t));
|
|
m_index = new_index;
|
|
}
|
|
|
|
template<typename T, typename StrippedT = RemoveCVReference<T>>
|
|
void set(T&& t, Detail::VariantNoClearTag)
|
|
requires(can_contain<StrippedT>() && requires { StrippedT(forward<T>(t)); })
|
|
{
|
|
constexpr auto new_index = index_of<StrippedT>();
|
|
new (m_data) StrippedT(forward<T>(t));
|
|
m_index = new_index;
|
|
}
|
|
|
|
template<typename T>
|
|
T* get_pointer()
|
|
requires(can_contain<T>())
|
|
{
|
|
if (index_of<T>() == m_index)
|
|
return bit_cast<T*>(&m_data);
|
|
return nullptr;
|
|
}
|
|
|
|
template<typename T>
|
|
T& get()
|
|
requires(can_contain<T>())
|
|
{
|
|
VERIFY(has<T>());
|
|
return *bit_cast<T*>(&m_data);
|
|
}
|
|
|
|
template<typename T>
|
|
T const* get_pointer() const
|
|
requires(can_contain<T>())
|
|
{
|
|
if (index_of<T>() == m_index)
|
|
return bit_cast<T const*>(&m_data);
|
|
return nullptr;
|
|
}
|
|
|
|
template<typename T>
|
|
T const& get() const
|
|
requires(can_contain<T>())
|
|
{
|
|
VERIFY(has<T>());
|
|
return *bit_cast<T const*>(&m_data);
|
|
}
|
|
|
|
template<typename T>
|
|
[[nodiscard]] bool has() const
|
|
requires(can_contain<T>())
|
|
{
|
|
return index_of<T>() == m_index;
|
|
}
|
|
|
|
bool operator==(Variant const& other) const
|
|
{
|
|
return this->visit([&]<typename T>(T const& self) {
|
|
if (auto const* p = other.get_pointer<T>())
|
|
return static_cast<T const&>(self) == static_cast<T const&>(*p);
|
|
return false;
|
|
});
|
|
}
|
|
|
|
template<typename... Fs>
|
|
ALWAYS_INLINE decltype(auto) visit(Fs&&... functions)
|
|
{
|
|
Visitor<Fs...> visitor { forward<Fs>(functions)... };
|
|
return VisitHelper::visit(*this, m_index, m_data, move(visitor));
|
|
}
|
|
|
|
template<typename... Fs>
|
|
ALWAYS_INLINE decltype(auto) visit(Fs&&... functions) const
|
|
{
|
|
Visitor<Fs...> visitor { forward<Fs>(functions)... };
|
|
return VisitHelper::visit(*this, m_index, m_data, move(visitor));
|
|
}
|
|
|
|
template<typename... NewTs>
|
|
decltype(auto) downcast() &&
|
|
{
|
|
if constexpr (sizeof...(NewTs) == 1 && (IsSpecializationOf<NewTs, Variant> && ...)) {
|
|
return move(*this).template downcast_variant<NewTs...>();
|
|
} else {
|
|
Variant<NewTs...> instance { Variant<NewTs...>::invalid_index, Detail::VariantConstructTag {} };
|
|
visit([&](auto& value) {
|
|
if constexpr (Variant<NewTs...>::template can_contain<RemoveCVReference<decltype(value)>>())
|
|
instance.set(move(value), Detail::VariantNoClearTag {});
|
|
});
|
|
VERIFY(instance.m_index != instance.invalid_index);
|
|
return instance;
|
|
}
|
|
}
|
|
|
|
template<typename... NewTs>
|
|
decltype(auto) downcast() const&
|
|
{
|
|
if constexpr (sizeof...(NewTs) == 1 && (IsSpecializationOf<NewTs, Variant> && ...)) {
|
|
return (*this).template downcast_variant(TypeWrapper<NewTs...> {});
|
|
} else {
|
|
Variant<NewTs...> instance { Variant<NewTs...>::invalid_index, Detail::VariantConstructTag {} };
|
|
visit([&](auto const& value) {
|
|
if constexpr (Variant<NewTs...>::template can_contain<RemoveCVReference<decltype(value)>>())
|
|
instance.set(value, Detail::VariantNoClearTag {});
|
|
});
|
|
VERIFY(instance.m_index != instance.invalid_index);
|
|
return instance;
|
|
}
|
|
}
|
|
|
|
auto index() const { return m_index; }
|
|
|
|
private:
|
|
template<typename... NewTs>
|
|
Variant<NewTs...> downcast_variant(TypeWrapper<Variant<NewTs...>>) &&
|
|
{
|
|
return move(*this).template downcast<NewTs...>();
|
|
}
|
|
|
|
template<typename... NewTs>
|
|
Variant<NewTs...> downcast_variant(TypeWrapper<Variant<NewTs...>>) const&
|
|
{
|
|
return (*this).template downcast<NewTs...>();
|
|
}
|
|
|
|
static constexpr auto data_size = Detail::integer_sequence_generate_array<size_t>(0, IntegerSequence<size_t, sizeof(Ts)...>()).max();
|
|
static constexpr auto data_alignment = Detail::integer_sequence_generate_array<size_t>(0, IntegerSequence<size_t, alignof(Ts)...>()).max();
|
|
using Helper = Detail::Variant<IndexType, 0, Ts...>;
|
|
using VisitHelper = Detail::VisitImpl<IndexType, Ts...>;
|
|
|
|
template<typename T_, typename U_>
|
|
friend struct Detail::VariantConstructors;
|
|
|
|
explicit Variant(IndexType index, Detail::VariantConstructTag)
|
|
: Detail::MergeAndDeduplicatePacks<Detail::VariantConstructors<Ts, Variant<Ts...>>...>()
|
|
, m_index(index)
|
|
{
|
|
}
|
|
|
|
ALWAYS_INLINE void clear_without_destruction()
|
|
{
|
|
__builtin_memset(m_data, 0, data_size);
|
|
m_index = invalid_index;
|
|
}
|
|
|
|
template<typename... Fs>
|
|
struct Visitor : Fs... {
|
|
using Types = TypeList<Fs...>;
|
|
|
|
Visitor(Fs&&... args)
|
|
: Fs(forward<Fs>(args))...
|
|
{
|
|
}
|
|
|
|
using Fs::operator()...;
|
|
};
|
|
|
|
// Note: Make sure not to default-initialize!
|
|
// VariantConstructors::VariantConstructors(T) will set this to the correct value
|
|
// So default-constructing to anything will leave the first initialization with that value instead of the correct one.
|
|
alignas(data_alignment) u8 m_data[data_size];
|
|
IndexType m_index;
|
|
};
|
|
|
|
template<typename... Ts>
|
|
struct TypeList<Variant<Ts...>> : TypeList<Ts...> { };
|
|
|
|
}
|
|
|
|
#if USING_AK_GLOBALLY
|
|
using AK::Empty;
|
|
using AK::Variant;
|
|
#endif
|