2024-10-31 01:08:01 +10:00

304 lines
10 KiB
C++

#ifndef ENTT_ENTITY_MIXIN_HPP
#define ENTT_ENTITY_MIXIN_HPP
#include <type_traits>
#include <utility>
#include "../config/config.h"
#include "../core/any.hpp"
#include "../signal/sigh.hpp"
#include "entity.hpp"
#include "fwd.hpp"
namespace entt {
/**
* @brief Mixin type used to add signal support to storage types.
*
* The function type of a listener is equivalent to:
*
* @code{.cpp}
* void(basic_registry<entity_type> &, entity_type);
* @endcode
*
* This applies to all signals made available.
*
* @tparam Type Underlying storage type.
* @tparam Registry Basic registry type.
*/
template<typename Type, typename Registry>
class basic_sigh_mixin final: public Type {
using underlying_type = Type;
using owner_type = Registry;
using basic_registry_type = basic_registry<typename underlying_type::entity_type, typename underlying_type::base_type::allocator_type>;
using sigh_type = sigh<void(owner_type &, const typename underlying_type::entity_type), typename underlying_type::allocator_type>;
using underlying_iterator = typename underlying_type::base_type::basic_iterator;
static_assert(std::is_base_of_v<basic_registry_type, owner_type>, "Invalid registry type");
owner_type &owner_or_assert() const noexcept {
ENTT_ASSERT(owner != nullptr, "Invalid pointer to registry");
return static_cast<owner_type &>(*owner);
}
void pop(underlying_iterator first, underlying_iterator last) final {
if(auto &reg = owner_or_assert(); destruction.empty()) {
underlying_type::pop(first, last);
} else {
for(; first != last; ++first) {
const auto entt = *first;
destruction.publish(reg, entt);
const auto it = underlying_type::find(entt);
underlying_type::pop(it, it + 1u);
}
}
}
void pop_all() final {
if(auto &reg = owner_or_assert(); !destruction.empty()) {
for(auto it = underlying_type::base_type::begin(0), last = underlying_type::base_type::end(0); it != last; ++it) {
if constexpr(std::is_same_v<typename underlying_type::value_type, typename underlying_type::entity_type>) {
destruction.publish(reg, *it);
} else {
if constexpr(underlying_type::traits_type::in_place_delete) {
if(const auto entt = *it; entt != tombstone) {
destruction.publish(reg, entt);
}
} else {
destruction.publish(reg, *it);
}
}
}
}
underlying_type::pop_all();
}
underlying_iterator try_emplace(const typename underlying_type::entity_type entt, const bool force_back, const void *value) final {
const auto it = underlying_type::try_emplace(entt, force_back, value);
if(auto &reg = owner_or_assert(); it != underlying_type::base_type::end()) {
construction.publish(reg, *it);
}
return it;
}
public:
/*! @brief Allocator type. */
using allocator_type = typename underlying_type::allocator_type;
/*! @brief Underlying entity identifier. */
using entity_type = typename underlying_type::entity_type;
/*! @brief Expected registry type. */
using registry_type = owner_type;
/*! @brief Default constructor. */
basic_sigh_mixin()
: basic_sigh_mixin{allocator_type{}} {}
/**
* @brief Constructs an empty storage with a given allocator.
* @param allocator The allocator to use.
*/
explicit basic_sigh_mixin(const allocator_type &allocator)
: underlying_type{allocator},
owner{},
construction{allocator},
destruction{allocator},
update{allocator} {}
/**
* @brief Move constructor.
* @param other The instance to move from.
*/
basic_sigh_mixin(basic_sigh_mixin &&other) noexcept
: underlying_type{std::move(other)},
owner{other.owner},
construction{std::move(other.construction)},
destruction{std::move(other.destruction)},
update{std::move(other.update)} {}
/**
* @brief Allocator-extended move constructor.
* @param other The instance to move from.
* @param allocator The allocator to use.
*/
basic_sigh_mixin(basic_sigh_mixin &&other, const allocator_type &allocator) noexcept
: underlying_type{std::move(other), allocator},
owner{other.owner},
construction{std::move(other.construction), allocator},
destruction{std::move(other.destruction), allocator},
update{std::move(other.update), allocator} {}
/**
* @brief Move assignment operator.
* @param other The instance to move from.
* @return This storage.
*/
basic_sigh_mixin &operator=(basic_sigh_mixin &&other) noexcept {
underlying_type::operator=(std::move(other));
owner = other.owner;
construction = std::move(other.construction);
destruction = std::move(other.destruction);
update = std::move(other.update);
return *this;
}
/**
* @brief Exchanges the contents with those of a given storage.
* @param other Storage to exchange the content with.
*/
void swap(basic_sigh_mixin &other) {
using std::swap;
underlying_type::swap(other);
swap(owner, other.owner);
swap(construction, other.construction);
swap(destruction, other.destruction);
swap(update, other.update);
}
/**
* @brief Returns a sink object.
*
* The sink returned by this function can be used to receive notifications
* whenever a new instance is created and assigned to an entity.<br/>
* Listeners are invoked after the object has been assigned to the entity.
*
* @sa sink
*
* @return A temporary sink object.
*/
[[nodiscard]] auto on_construct() noexcept {
return sink{construction};
}
/**
* @brief Returns a sink object.
*
* The sink returned by this function can be used to receive notifications
* whenever an instance is explicitly updated.<br/>
* Listeners are invoked after the object has been updated.
*
* @sa sink
*
* @return A temporary sink object.
*/
[[nodiscard]] auto on_update() noexcept {
return sink{update};
}
/**
* @brief Returns a sink object.
*
* The sink returned by this function can be used to receive notifications
* whenever an instance is removed from an entity and thus destroyed.<br/>
* Listeners are invoked before the object has been removed from the entity.
*
* @sa sink
*
* @return A temporary sink object.
*/
[[nodiscard]] auto on_destroy() noexcept {
return sink{destruction};
}
/**
* @brief Emplace elements into a storage.
*
* The behavior of this operation depends on the underlying storage type
* (for example, components vs entities).<br/>
* Refer to the specific documentation for more details.
*
* @return A return value as returned by the underlying storage.
*/
auto emplace() {
const auto entt = underlying_type::emplace();
construction.publish(owner_or_assert(), entt);
return entt;
}
/**
* @brief Emplace elements into a storage.
*
* The behavior of this operation depends on the underlying storage type
* (for example, components vs entities).<br/>
* Refer to the specific documentation for more details.
*
* @tparam Args Types of arguments to forward to the underlying storage.
* @param hint A valid identifier.
* @param args Parameters to forward to the underlying storage.
* @return A return value as returned by the underlying storage.
*/
template<typename... Args>
decltype(auto) emplace(const entity_type hint, Args &&...args) {
if constexpr(std::is_same_v<typename underlying_type::value_type, typename underlying_type::entity_type>) {
const auto entt = underlying_type::emplace(hint, std::forward<Args>(args)...);
construction.publish(owner_or_assert(), entt);
return entt;
} else {
underlying_type::emplace(hint, std::forward<Args>(args)...);
construction.publish(owner_or_assert(), hint);
return this->get(hint);
}
}
/**
* @brief Patches the given instance for an entity.
* @tparam Func Types of the function objects to invoke.
* @param entt A valid identifier.
* @param func Valid function objects.
* @return A reference to the patched instance.
*/
template<typename... Func>
decltype(auto) patch(const entity_type entt, Func &&...func) {
underlying_type::patch(entt, std::forward<Func>(func)...);
update.publish(owner_or_assert(), entt);
return this->get(entt);
}
/**
* @brief Emplace elements into a storage.
*
* The behavior of this operation depends on the underlying storage type
* (for example, components vs entities).<br/>
* Refer to the specific documentation for more details.
*
* @tparam It Iterator type (as required by the underlying storage type).
* @tparam Args Types of arguments to forward to the underlying storage.
* @param first An iterator to the first element of the range.
* @param last An iterator past the last element of the range.
* @param args Parameters to use to forward to the underlying storage.
*/
template<typename It, typename... Args>
void insert(It first, It last, Args &&...args) {
auto from = underlying_type::size();
underlying_type::insert(first, last, std::forward<Args>(args)...);
if(auto &reg = owner_or_assert(); !construction.empty()) {
for(const auto to = underlying_type::size(); from != to; ++from) {
construction.publish(reg, underlying_type::operator[](from));
}
}
}
/**
* @brief Forwards variables to derived classes, if any.
* @param value A variable wrapped in an opaque container.
*/
void bind(any value) noexcept final {
auto *reg = any_cast<basic_registry_type>(&value);
owner = reg ? reg : owner;
underlying_type::bind(std::move(value));
}
private:
basic_registry_type *owner;
sigh_type construction;
sigh_type destruction;
sigh_type update;
};
} // namespace entt
#endif