Delegate.hpp

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// ======================================================================
// \title Os/Delegate.hpp
// \brief helper functions to ease correct getDelegate implementations
// ======================================================================
#include <new>
#include <type_traits>
#include "Fw/Types/Assert.hpp"
#include "Os/Os.hpp"
#ifndef OS_DELEGATE_HPP_
#define OS_DELEGATE_HPP_
namespace Os {
namespace Delegate {
 
template <class Interface, class Implementation, class StorageType>
inline Interface* makeDelegate(StorageType& aligned_new_memory) {
    // Ensure prerequisites before performing placement new
    static_assert(std::is_base_of<Interface, Implementation>::value, "Implementation must derive from Interface");
    static_assert(sizeof(Implementation) <= sizeof(StorageType), "Handle size not large enough");
    static_assert((FW_HANDLE_ALIGNMENT % alignof(Implementation)) == 0, "Handle alignment invalid");
    // Placement new the object and ensure non-null result
    Implementation* interface = new (aligned_new_memory) Implementation;
    FW_ASSERT(interface != nullptr);
    return interface;
}
 
template <class Interface, class Implementation, class StorageType>
inline Interface* makeDelegate(StorageType& aligned_new_memory, const Interface* to_copy) {
    const Implementation* copy_me = reinterpret_cast<const Implementation*>(to_copy);
    // Ensure prerequisites before performing placement new
    static_assert(std::is_base_of<Interface, Implementation>::value, "Implementation must derive from Interface");
    static_assert(sizeof(Implementation) <= sizeof(aligned_new_memory), "Handle size not large enough");
    static_assert((FW_HANDLE_ALIGNMENT % alignof(Implementation)) == 0, "Handle alignment invalid");
    // Placement new the object and ensure non-null result
    Implementation* interface = nullptr;
    if (to_copy == nullptr) {
        interface = new (aligned_new_memory) Implementation;
    } else {
        interface = new (aligned_new_memory) Implementation(*copy_me);
    }
    FW_ASSERT(interface != nullptr);
    return interface;
}
}  // namespace Delegate
}  // namespace Os
#endif