IObject.h#
Fully qualified name: omni/core/IObject.h
File members: omni/core/IObject.h
// Copyright (c) 2020-2023, NVIDIA CORPORATION. All rights reserved.
//
// NVIDIA CORPORATION and its licensors retain all intellectual property
// and proprietary rights in and to this software, related documentation
// and any modifications thereto. Any use, reproduction, disclosure or
// distribution of this software and related documentation without an express
// license agreement from NVIDIA CORPORATION is strictly prohibited.
//
#pragma once
#include "Assert.h"
#include "Result.h"
#include "TypeId.h"
#include "OmniAttr.h"
#include <atomic>
#include <climits> // CHAR_BITS
#include <type_traits>
namespace omni
{
namespace core
{
// we assume 8-bit chars
static_assert(CHAR_BIT == 8, "non-octet char is not supported");
class IObject_abi;
class IObject;
class OMNI_ATTR("no_py") IObject_abi
{
public:
#ifndef DOXYGEN_SHOULD_SKIP_THIS
enum : TypeId
{
kTypeId = OMNI_TYPE_ID("omni.core.IObject")
};
#endif
protected:
virtual void* cast_abi(TypeId id) noexcept = 0;
virtual void acquire_abi() noexcept = 0;
virtual void release_abi() noexcept = 0;
};
} // namespace core
} // namespace omni
#define OMNI_BIND_INCLUDE_INTERFACE_DECL
#include "IObject.gen.h"
namespace omni
{
namespace core
{
class IObject : public omni::core::Generated<omni::core::IObject_abi>
{
};
template <typename BASE, TypeId TYPEID>
class Inherits : public BASE
{
public:
#ifndef DOXYGEN_BUILD
enum : TypeId
{
kTypeId = TYPEID
};
using BaseType = BASE;
#endif
};
#ifndef DOXYGEN_BUILD
namespace detail
{
class BorrowPtrType
{
public:
explicit BorrowPtrType() noexcept = default;
};
} // namespace detail
#endif
constexpr detail::BorrowPtrType kBorrow{};
#ifndef DOXYGEN_BUILD
namespace detail
{
class StealPtrType
{
public:
explicit StealPtrType() noexcept = default;
};
} // namespace detail
#endif
constexpr detail::StealPtrType kSteal{};
template <typename T>
class ObjectPtr
{
public:
constexpr ObjectPtr(std::nullptr_t = nullptr) noexcept
{
}
ObjectPtr(T* other, detail::BorrowPtrType) noexcept : m_ptr(other)
{
addRef();
}
constexpr ObjectPtr(T* other, detail::StealPtrType) noexcept : m_ptr(other)
{
}
ObjectPtr(const ObjectPtr& other) noexcept : m_ptr(other.m_ptr)
{
addRef();
}
template <typename U>
ObjectPtr(const ObjectPtr<U>& other) noexcept : m_ptr(other.m_ptr)
{
addRef();
}
template <typename U>
ObjectPtr(ObjectPtr<U>&& other) noexcept : m_ptr(std::exchange(other.m_ptr, {}))
{
}
~ObjectPtr() noexcept
{
releaseRef();
}
ObjectPtr& operator=(const ObjectPtr& other) noexcept
{
copyRef(other.m_ptr);
return *this;
}
ObjectPtr& operator=(ObjectPtr&& other) noexcept
{
if (this != &other)
{
releaseRef();
m_ptr = std::exchange(other.m_ptr, {});
}
return *this;
}
template <typename U>
ObjectPtr& operator=(const ObjectPtr<U>& other) noexcept
{
copyRef(other.m_ptr);
return *this;
}
template <typename U>
ObjectPtr& operator=(ObjectPtr<U>&& other) noexcept
{
releaseRef();
m_ptr = std::exchange(other.m_ptr, {});
return *this;
}
explicit operator bool() const noexcept
{
return m_ptr != nullptr;
}
T* operator->() const noexcept
{
return m_ptr;
}
T& operator*() const noexcept
{
return *m_ptr;
}
T* get() const noexcept
{
return m_ptr;
}
T** put() noexcept
{
OMNI_ASSERT(m_ptr == nullptr);
return &m_ptr;
}
void steal(T* value) noexcept
{
releaseRef();
*put() = value;
}
T* detach() noexcept
{
return std::exchange(m_ptr, {});
}
void borrow(T* value) noexcept
{
releaseRef();
*put() = value;
addRef();
}
template <typename To>
ObjectPtr<To> as() const noexcept
{
if (!m_ptr)
{
return nullptr; // dynamic_cast allows a nullptr, so we do as well
}
else
{
return ObjectPtr<To>(reinterpret_cast<To*>(m_ptr->cast(To::kTypeId)), kSteal);
}
}
template <typename To>
void as(ObjectPtr<To>& to) const noexcept
{
if (!m_ptr)
{
to.steal(nullptr); // dynamic_cast allows a nullptr, so we do as well
}
else
{
to.steal(reinterpret_cast<To*>(m_ptr->cast(To::kTypeId)));
}
}
void release() noexcept
{
releaseRef();
}
void reset(T* value = nullptr) noexcept
{
if (value)
{
const_cast<std::remove_const_t<T>*>(value)->acquire();
}
T* oldval = std::exchange(m_ptr, value);
if (oldval)
{
oldval->release();
}
}
private:
void copyRef(T* other) noexcept
{
if (m_ptr != other)
{
releaseRef();
m_ptr = other;
addRef();
}
}
void addRef() const noexcept
{
if (m_ptr)
{
const_cast<std::remove_const_t<T>*>(m_ptr)->acquire();
}
}
void releaseRef() noexcept
{
if (m_ptr)
{
std::exchange(m_ptr, {})->release();
}
}
template <typename U>
friend class ObjectPtr;
T* m_ptr{};
};
// Breathe/Sphinx is unable to handle these overloads and produces warnings. Since we don't like warnings, remove these
// overloads from the docs until Breathe/Sphinx is updated.
#ifndef DOXYGEN_SHOULD_SKIP_THIS
template <typename T>
inline bool operator<(const ObjectPtr<T>& left, const ObjectPtr<T>& right) noexcept
{
return (left.get() < right.get());
}
template <typename T>
inline bool operator==(const ObjectPtr<T>& left, const ObjectPtr<T>& right) noexcept
{
return (left.get() == right.get());
}
template <typename T>
inline bool operator==(const ObjectPtr<T>& left, const T* right) noexcept
{
return (left.get() == right);
}
template <typename T>
inline bool operator==(const T* left, const ObjectPtr<T>& right) noexcept
{
return (left == right.get());
}
template <typename T>
inline bool operator==(const ObjectPtr<T>& left, std::nullptr_t) noexcept
{
return (left.get() == nullptr);
}
template <typename T>
inline bool operator==(std::nullptr_t, const ObjectPtr<T>& right) noexcept
{
return (right.get() == nullptr);
}
template <typename T>
inline bool operator!=(const ObjectPtr<T>& left, const ObjectPtr<T>& right) noexcept
{
return (left.get() != right.get());
}
template <typename T>
inline bool operator!=(const ObjectPtr<T>& left, const T* right) noexcept
{
return (left.get() != right);
}
template <typename T>
inline bool operator!=(const T* left, const ObjectPtr<T>& right) noexcept
{
return (left != right.get());
}
template <typename T>
inline bool operator!=(const ObjectPtr<T>& left, std::nullptr_t) noexcept
{
return (left.get() != nullptr);
}
template <typename T>
inline bool operator!=(std::nullptr_t, const ObjectPtr<T>& right) noexcept
{
return (right.get() != nullptr);
}
#endif // DOXYGEN_SHOULD_SKIP_THIS
template <typename T>
inline ObjectPtr<T> steal(T* ptr) noexcept
{
return ObjectPtr<T>(ptr, kSteal);
}
template <typename T>
inline ObjectPtr<T> borrow(T* ptr) noexcept
{
return ObjectPtr<T>(ptr, kBorrow);
}
template <typename T, typename U>
inline ObjectPtr<T> cast(U* ptr) noexcept
{
static_assert(std::is_base_of<IObject, T>::value, "cast can only be used with classes that derive from IObject");
if (ptr)
{
return ObjectPtr<T>{ reinterpret_cast<T*>(ptr->cast(T::kTypeId)), kSteal };
}
else
{
return { nullptr };
}
}
#ifndef DOXYGEN_BUILD
namespace detail
{
template <typename T>
inline void* cast(T* obj, TypeId id) noexcept; // forward declaration
} // namespace detail
#endif
template <typename T, typename... Rest>
struct ImplementsCast : public T, public Rest...
{
public:
inline void* cast(omni::core::TypeId id) noexcept
{
// note: this implementation is needed to disambiguate which `cast` to call when using multiple inheritance. it
// has zero-overhead.
return static_cast<T*>(this)->cast(id);
}
private:
// given a type id, castImpl() check if the type id matches T's typeid. if not, T's parent class type id is
// checked. if T's parent class type id does not match, the grandparent class's type id is check. this continues
// until IObject's type id is checked.
//
// if no type id in T's inheritance chain match, the next interface in Rest is checked.
//
// it's expected the compiler can optimize away the recursion
template <typename U, typename... Args>
inline void* castImpl(TypeId id) noexcept
{
// detail::cast will march down the inheritance chain
void* obj = omni::core::detail::cast<U>(this, id);
if (nullptr == obj)
{
// check the next class (inheritance chain) provide in the inheritance list
return castImpl<Args...>(id);
}
return obj;
}
// this terminates walking across the types in the variadic template
template <int = 0>
inline void* castImpl(TypeId) noexcept
{
return nullptr;
}
protected:
virtual ~ImplementsCast() noexcept = default;
virtual void* cast_abi(TypeId id) noexcept override
{
return castImpl<T, Rest...>(id);
}
};
template <typename T, typename... Rest>
struct Implements : public ImplementsCast<T, Rest...>
{
public:
inline void acquire() noexcept
{
// note: this implementation is needed to disambiguate which `cast` to call when using multiple inheritance. it
// has zero-overhead.
static_cast<T*>(this)->acquire();
}
inline void release() noexcept
{
// note: this implementation is needed to disambiguate which `cast` to call when using multiple inheritance. it
// has zero-overhead.
static_cast<T*>(this)->release();
}
protected:
std::atomic<uint32_t> m_refCount{ 1 };
virtual ~Implements() noexcept = default;
virtual void acquire_abi() noexcept override
{
m_refCount.fetch_add(1, std::memory_order_relaxed);
}
virtual void release_abi() noexcept override
{
if (0 == m_refCount.fetch_sub(1, std::memory_order_release) - 1)
{
std::atomic_thread_fence(std::memory_order_acquire);
delete this;
}
}
};
#ifndef DOXYGEN_BUILD
namespace detail
{
template <typename T>
inline void* cast(T* obj, TypeId id) noexcept
{
if (T::kTypeId == id)
{
obj->acquire(); // match! since we return an interface pointer, acquire() must be called.
return obj;
}
else
{
return cast<typename T::BaseType>(obj, id); // call cast again, but with the parent type
}
}
template <>
inline void* cast<IObject>(IObject* obj, TypeId id) noexcept
{
if (IObject::kTypeId == id)
{
obj->acquire();
return obj;
}
else
{
return nullptr;
}
}
} // namespace detail
#endif
} // namespace core
} // namespace omni
#define OMNI_BIND_INCLUDE_INTERFACE_IMPL
#include "IObject.gen.h"