mijin2/source/mijin/util/property.hpp

109 lines
3.2 KiB
C++

#pragma once
#ifndef MIJIN_UTIL_PROPERTY_HPP_INCLUDED
#define MIJIN_UTIL_PROPERTY_HPP_INCLUDED 1
#include <memory>
#include <utility>
#include "../debug/assert.hpp"
namespace mijin
{
//
// public defines
//
//
// public types
//
template<typename T, typename TGet = const T&, typename TSet = T>
class PropertyStorage
{
public:
using value_t = T;
using get_t = TGet;
using set_t = TSet;
virtual ~PropertyStorage() noexcept = default;
[[nodiscard]] virtual TGet getValue() = 0;
virtual void setValue(TSet value) = 0;
};
template<typename T>
class SimplePropertyStorage : public PropertyStorage<T>
{
private:
T value_;
public:
SimplePropertyStorage() noexcept = default;
SimplePropertyStorage(const SimplePropertyStorage& other) noexcept(noexcept(T(other.value_))) = default;
SimplePropertyStorage(SimplePropertyStorage&& other) noexcept(noexcept(T(std::move(other.value_)))) = default;
explicit SimplePropertyStorage(T value) noexcept(noexcept(T(std::move(value)))) : value_(std::move(value)) {}
SimplePropertyStorage& operator=(const SimplePropertyStorage& other) noexcept(noexcept(value_ = other.value_)) = default;
SimplePropertyStorage& operator=(SimplePropertyStorage&& other) noexcept(noexcept(value_ = std::move(other.value_))) = default;
const T& getValue() noexcept override { return value_; }
void setValue(T value) override { value_ = std::move(value); }
};
template<typename T, typename TGet = const T&, typename TSet = T>
class Property
{
private:
using storage_t = PropertyStorage<T, TGet, TSet>;
using storage_ptr_t = std::unique_ptr<storage_t>;
storage_ptr_t storage_;
public:
class PropertyProxy
{
private:
Property* base_;
public:
explicit PropertyProxy(Property* base) noexcept : base_(base) {}
operator TGet() noexcept { return base_->get(); }
PropertyProxy& operator=(TSet value) noexcept(noexcept(std::declval<T&>() = std::move(value)))
{
base_->set(std::move(value));
return *this;
}
};
Property() noexcept = default;
explicit Property(storage_ptr_t storage) noexcept : storage_(std::move(storage)) {}
Property(Property&&) noexcept = default;
Property& operator=(Property&&) noexcept = default;
PropertyProxy operator*() noexcept { return PropertyProxy(this); }
std::remove_reference_t<TGet>* operator->() const noexcept { return &get(); }
[[nodiscard]] TGet get() const noexcept
{
MIJIN_ASSERT_FATAL(storage_ != nullptr, "Cannot get value from an unset property.");
return storage_->getValue();
}
void set(TSet value) noexcept(noexcept(std::declval<T&>() = std::move(value)))
{
MIJIN_ASSERT_FATAL(storage_ != nullptr, "Cannot set value of an unset property.");
storage_->setValue(std::move<TSet>(value));
}
};
template<typename TStorage>
Property(std::unique_ptr<TStorage>) -> Property<typename TStorage::value_t, typename TStorage::get_t, typename TStorage::set_t>;
template<typename T>
Property<T> makeSimpleProperty(T value) noexcept(noexcept(std::declval<T&>() = std::move(value)))
{
return Property(std::make_unique<SimplePropertyStorage<T>>(std::move(value)));
}
}
#endif // MIJIN_UTIL_PROPERTY_HPP_INCLUDED