// Copyright Microsoft and CHERIoT Contributors.
// SPDX-License-Identifier: MIT

#pragma once
/**
 * This file contains concrete implementations of the C++ replaceable new and
 * delete functions, as thin wrappers around calls to the allocator
 * compartment.
 *
 * These are intended to be small and inlined for normal use but have blocking
 * behaviour that may be inappropriate for some uses.  Individual compartments
 * can opt out of these definitions by defining `CHERIOT_NO_NEW_DELETE`.
 *
 * The `CHERIOT_NO_AMBIENT_MALLOC` macro will also hide these, because they
 * depend on having ambient authority to allocate memory.
 */
#include_next <new>
#include <stdlib.h>

#if !defined(CHERIOT_NO_NEW_DELETE) && !defined(CHERIOT_NO_AMBIENT_MALLOC)
namespace std
{
	/**
	 * Implementation details.
	 */
	namespace __new_detail
	{
		/**
		 * Class for managing the handler for new and delete.
		 */
		class NewHelper
		{
			/**
			 * Pointer to the handler for allocation failures.
			 */
			static inline std::new_handler newHandler;

			/// The standard getter is allowed to access the new handler
			friend std::new_handler std::get_new_handler() _NOEXCEPT;
			/// The standard setter is allowed to modify the new handler
			friend std::new_handler std::set_new_handler(new_handler) _NOEXCEPT;

			public:
			/**
			 * Helper to call the allocator and raise an error if allocation fails.
			 */
			static inline void *allocate(size_t size)
			{
				void *ptr = malloc(size);
				while (ptr == nullptr)
				{
					if (newHandler)
					{
						newHandler();
					}
					else
					{
						break;
					}
				}
				return ptr;
			}
		};
	} // namespace __new_detail

	/**
	 * Return the handler for allocation failure.
	 */
	inline new_handler get_new_handler() noexcept
	{
		return __new_detail::NewHelper::newHandler;
	}

	/**
	 * Set the handler for allocation failure and return the old one.
	 *
	 * Note: This implementation is *not* thread safe!
	 */
	inline new_handler set_new_handler(new_handler new_p) noexcept
	{
		auto old = __new_detail::NewHelper::newHandler;
		__new_detail::NewHelper::newHandler = new_p;
		return old;
	}

} // namespace std

#	pragma clang diagnostic push
#	pragma clang diagnostic ignored "-Winline-new-delete"

_LIBCPP_NODISCARD_AFTER_CXX17
  __always_inline _LIBCPP_OVERRIDABLE_FUNC_VIS inline void *
  operator new(std::size_t size)
{
	return std::__new_detail::NewHelper::allocate(size);
}

_LIBCPP_NODISCARD_AFTER_CXX17
  __always_inline _LIBCPP_OVERRIDABLE_FUNC_VIS inline void *
  operator new(std::size_t size, const std::nothrow_t &) noexcept
{
	return std::__new_detail::NewHelper::allocate(size);
}

_LIBCPP_NODISCARD_AFTER_CXX17
  __always_inline _LIBCPP_OVERRIDABLE_FUNC_VIS inline void *
  operator new[](std::size_t size)
{
	return std::__new_detail::NewHelper::allocate(size);
}
_LIBCPP_NODISCARD_AFTER_CXX17
  __always_inline _LIBCPP_OVERRIDABLE_FUNC_VIS inline void *
  operator new[](std::size_t size, const std::nothrow_t &) noexcept
{
	return std::__new_detail::NewHelper::allocate(size);
}
__always_inline _LIBCPP_OVERRIDABLE_FUNC_VIS inline void
operator delete(void *ptr) noexcept
{
	::free(ptr);
}
__always_inline _LIBCPP_OVERRIDABLE_FUNC_VIS inline void
operator delete(void *ptr, std::size_t size) noexcept
{
	::free(ptr);
}

__always_inline _LIBCPP_OVERRIDABLE_FUNC_VIS inline void
operator delete[](void *ptr) noexcept
{
	::free(ptr);
}
__always_inline _LIBCPP_OVERRIDABLE_FUNC_VIS inline void
operator delete[](void *ptr, std::size_t size) noexcept
{
	::free(ptr);
}
__always_inline _LIBCPP_OVERRIDABLE_FUNC_VIS inline void
operator delete[](void *ptr, const std::nothrow_t &) noexcept
{
	::free(ptr);
}

#	if 0
// Until the allocator exposes a memalign interface, we don't support aligned allocation.
[[nodiscard]] void* operator new(std::size_t size, std::align_val_t alignment);
[[nodiscard]] void* operator new(std::size_t size, std::align_val_t alignment,
                                 const std::nothrow_t&) noexcept;

void operator delete(void *ptr, std::align_val_t alignment) noexcept;
void operator delete(void            *ptr,
                     std::size_t      size,
                     std::align_val_t alignment) noexcept;
void operator delete(void *ptr, const std::nothrow_t &) noexcept;
void operator delete(void            *ptr,
                     std::align_val_t alignment,
                     const std::nothrow_t &) noexcept;
[[nodiscard]] void *operator new[](std::size_t      size,
                                   std::align_val_t alignment);
[[nodiscard]] void *operator new[](std::size_t      size,
                                   std::align_val_t alignment,
                                   const std::nothrow_t &) noexcept;
void operator delete[](void *ptr, std::align_val_t alignment) noexcept;
void operator delete[](void            *ptr,
                       std::size_t      size,
                       std::align_val_t alignment) noexcept;
void operator delete[](void            *ptr,
                       std::align_val_t alignment,
                       const std::nothrow_t &) noexcept;

#	endif
#	pragma clang diagnostic pop
#endif