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meta: lazy initialization for nodes in meta_any

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This commit is contained in:
skypjack
2025-09-08 15:42:50 +02:00
parent d81e57daa1
commit fdaaeea52d
2 changed files with 21 additions and 16 deletions
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1
TODO
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@@ -32,5 +32,4 @@ TODO:
* avoid copying meta_type nodes, and use unique_ptr for meta_custom
* paged vector as a standalone class
* resource: shared_from_this?
* meta perf: the node in the meta_any is pretty much irrelevant, but it affects perf a lot (also fix natvis after this)
* change meta_any::base name, it's confusing due to meta_base_node and base types in meta

36
src/entt/meta/meta.hpp
View File

@@ -199,11 +199,19 @@ class meta_any {
ctx{other.ctx} {
if(storage || !other.storage) {
resolve = other.resolve;
node = other.node;
lazy_node = other.lazy_node;
vtable = other.vtable;
}
}
const auto &fetch_node() const {
if((lazy_node.info == nullptr) && (resolve != nullptr)) {
lazy_node = resolve(internal::meta_context::from(*ctx));
}
return lazy_node;
}
public:
/*! Default constructor. */
meta_any() = default;
@@ -237,7 +245,6 @@ public:
: storage{std::in_place_type<Type>, std::forward<Args>(args)...},
ctx{&area},
resolve{&internal::resolve<std::remove_cv_t<std::remove_reference_t<Type>>>},
node{resolve(internal::meta_context::from(*ctx))},
vtable{&basic_vtable<std::remove_cv_t<std::remove_reference_t<Type>>>} {}
/**
@@ -261,7 +268,6 @@ public:
ctx{&area} {
if(storage) {
resolve = &internal::resolve<Type>;
node = resolve(internal::meta_context::from(*ctx));
vtable = &basic_vtable<Type>;
}
}
@@ -294,7 +300,7 @@ public:
: storage{other.storage},
ctx{&area},
resolve{other.resolve},
node{((ctx != other.ctx) && (resolve != nullptr)) ? resolve(internal::meta_context::from(*ctx)) : other.node},
lazy_node{(ctx == other.ctx) ? other.lazy_node : internal::meta_type_node{}},
vtable{other.vtable} {}
/**
@@ -306,7 +312,7 @@ public:
: storage{std::move(other.storage)},
ctx{&area},
resolve{std::exchange(other.resolve, nullptr)},
node{((ctx != other.ctx) && (resolve != nullptr)) ? resolve(internal::meta_context::from(*ctx)) : std::exchange(other.node, internal::meta_type_node{})},
lazy_node{(ctx == other.ctx) ? std::exchange(other.lazy_node, internal::meta_type_node{}) : internal::meta_type_node{}},
vtable{std::exchange(other.vtable, nullptr)} {}
/**
@@ -335,7 +341,7 @@ public:
storage = other.storage;
ctx = other.ctx;
resolve = other.resolve;
node = other.node;
lazy_node = other.lazy_node;
vtable = other.vtable;
}
@@ -356,7 +362,7 @@ public:
storage = std::move(other.storage);
ctx = other.ctx;
resolve = std::exchange(other.resolve, nullptr);
node = std::exchange(other.node, internal::meta_type_node{});
lazy_node = std::exchange(other.lazy_node, internal::meta_type_node{});
vtable = std::exchange(other.vtable, nullptr);
return *this;
}
@@ -418,7 +424,7 @@ public:
template<typename Type>
[[nodiscard]] const Type *try_cast() const {
const auto *elem = any_cast<const Type>(&storage);
return (elem != nullptr) ? elem : static_cast<const Type *>(internal::try_cast(internal::meta_context::from(*ctx), node, type_id<std::remove_cv_t<Type>>().hash(), storage.data()));
return (elem != nullptr) ? elem : static_cast<const Type *>(internal::try_cast(internal::meta_context::from(*ctx), fetch_node(), type_id<std::remove_cv_t<Type>>().hash(), storage.data()));
}
/*! @copydoc try_cast */
@@ -429,7 +435,7 @@ public:
} else {
auto *elem = any_cast<Type>(&storage);
// NOLINTNEXTLINE(bugprone-casting-through-void)
return (elem != nullptr) ? elem : static_cast<Type *>(const_cast<void *>(internal::try_cast(internal::meta_context::from(*ctx), node, type_id<Type>().hash(), storage.data())));
return (elem != nullptr) ? elem : static_cast<Type *>(const_cast<void *>(internal::try_cast(internal::meta_context::from(*ctx), fetch_node(), type_id<Type>().hash(), storage.data())));
}
}
@@ -513,7 +519,7 @@ public:
void emplace(Args &&...args) {
storage.emplace<Type>(std::forward<Args>(args)...);
resolve = internal::resolve<std::remove_cv_t<std::remove_reference_t<Type>>>;
node = resolve(internal::meta_context::from(*ctx));
lazy_node = internal::meta_type_node{};
vtable = &basic_vtable<std::remove_cv_t<std::remove_reference_t<Type>>>;
}
@@ -527,7 +533,7 @@ public:
void reset() {
storage.reset();
resolve = nullptr;
node = {};
lazy_node = {};
vtable = nullptr;
}
@@ -624,7 +630,7 @@ private:
any storage;
const meta_ctx *ctx{&locator<meta_ctx>::value_or()};
internal::meta_type_node (*resolve)(const internal::meta_context &) noexcept {};
internal::meta_type_node node{};
mutable internal::meta_type_node lazy_node{};
vtable_type *vtable{};
};
@@ -1539,7 +1545,7 @@ private:
}
[[nodiscard]] inline meta_type meta_any::type() const noexcept {
return meta_type{*ctx, node};
return meta_type{*ctx, fetch_node()};
}
template<typename... Args>
@@ -1567,7 +1573,7 @@ bool meta_any::set(const id_type id, Type &&value) {
}
[[nodiscard]] inline meta_any meta_any::allow_cast(const meta_type &type) const {
return (storage.info() == type.info()) ? as_ref() : internal::try_convert(internal::meta_context::from(*ctx), node, type.info().hash(), type.is_arithmetic() || type.is_enum(), storage.data(), [this, &type]([[maybe_unused]] const void *instance, [[maybe_unused]] auto &&...args) {
return (storage.info() == type.info()) ? as_ref() : internal::try_convert(internal::meta_context::from(*ctx), fetch_node(), type.info().hash(), type.is_arithmetic() || type.is_enum(), storage.data(), [this, &type]([[maybe_unused]] const void *instance, [[maybe_unused]] auto &&...args) {
if constexpr((std::is_same_v<std::remove_const_t<std::remove_reference_t<decltype(args)>>, internal::meta_type_node> || ...)) {
return (args.from_void(*ctx, nullptr, instance), ...);
} else if constexpr((std::is_same_v<std::remove_const_t<std::remove_reference_t<decltype(args)>>, internal::meta_conv_node> || ...)) {
@@ -1576,7 +1582,7 @@ bool meta_any::set(const id_type id, Type &&value) {
// exploits the fact that arithmetic types and enums are also default constructible
auto other = type.construct();
const auto value = (args(nullptr, instance), ...);
other.node.conversion_helper(other.storage.data(), &value);
other.fetch_node().conversion_helper(other.storage.data(), &value);
return other;
} else {
// forwards to force a compile-time error in case of available arguments