omni::core::IWeakObject

Defined in omni/core/IWeakObject.h

class IWeakObject : public omni::core::Generated<omni::core::IWeakObject_abi>

Interface defining a contract for objects which support “weak”/non-owning references.

This interface works tightly with WeakPtr to implement weak pointers. Users of weak pointers should focus on WeakPtr rather than this interface, as this interface is an implementation detail of the weak pointer ABI.

Developers wishing to add weak pointer support to their objects must implement this interface, which is a non-trivial task. A default implementation is provided in ImplementsWeak.

Public Functions

inline omni::core::ObjectPtr<omni::core::IWeakObjectControlBlock> getWeakObjectControlBlock() noexcept

Returns a control block containing reference count information needed for the implementation of weak pointers.

Users of weak pointers must never call this method. Rather, they should focus on exclusively using WeakPtr.

Implementers of this method are encouraged to use the implementation found in omni::core::ImplementsWeak.

The returns pointer is never nullptr.

The returned pointer will have IObject::acquire() called on it before being returned.

Thread Safety

This method is thread safe.

inline void *cast(omni::core::TypeId id) noexcept

Returns a pointer to the interface defined by the given type id if this object implements the type id’s interface.

Objects can support multiple interfaces, even interfaces that are in different inheritance chains.

The returned object will have omni::core::IObject::acquire() called on it before it is returned, meaning it is up to the caller to call omni::core::IObject::release() on the returned pointer.

The returned pointer can be safely reinterpret_cast<> to the type id’s C++ class. For example, “omni.windowing.IWindow” can be cast to omni::windowing::IWindow.

Do not directly use this method, rather use a wrapper function like omni::core::cast() or omni::core::ObjectPtr::as().

Thread Safety

This method is thread safe.

inline void acquire() noexcept

Increments the object’s reference count.

Objects may have multiple reference counts (e.g. one per interface implemented). As such, it is important that you call omni::core::IObject::release() on the same pointer from which you called omni::core::IObject::acquire().

Do not directly use this method, rather use omni::core::ObjectPtr, which will manage calling omni::core::IObject::acquire() and omni::core::IObject::release() for you.

Thread Safety

This method is thread safe.

inline void release() noexcept

Decrements the objects reference count.

Most implementations will destroy the object if the reference count reaches 0 (though this is not a requirement).

Objects may have multiple reference counts (e.g. one per interface implemented). As such, it is important that you call omni::core::IObject::release() on the same pointer from which you called omni::core::IObject::acquire().

Do not directly use this method, rather use omni::core::ObjectPtr, which will manage calling omni::core::IObject::acquire() and omni::core::IObject::release() for you.

Thread Safety

This method is thread safe.

Protected Functions

virtual IWeakObjectControlBlock *getWeakObjectControlBlock_abi() noexcept = 0

Returns a control block containing reference count information needed for the implementation of weak pointers.

Users of weak pointers must never call this method. Rather, they should focus on exclusively using WeakPtr.

Implementers of this method are encouraged to use the implementation found in omni::core::ImplementsWeak.

The returns pointer is never nullptr.

The returned pointer will have IObject::acquire() called on it before being returned.

Thread Safety

This method is thread safe.

virtual void *cast_abi(TypeId id) noexcept = 0

Returns a pointer to the interface defined by the given type id if this object implements the type id’s interface.

Objects can support multiple interfaces, even interfaces that are in different inheritance chains.

The returned object will have omni::core::IObject::acquire() called on it before it is returned, meaning it is up to the caller to call omni::core::IObject::release() on the returned pointer.

The returned pointer can be safely reinterpret_cast<> to the type id’s C++ class. For example, “omni.windowing.IWindow” can be cast to omni::windowing::IWindow.

Do not directly use this method, rather use a wrapper function like omni::core::cast() or omni::core::ObjectPtr::as().

Thread Safety

This method is thread safe.

virtual void acquire_abi() noexcept = 0

Increments the object’s reference count.

Objects may have multiple reference counts (e.g. one per interface implemented). As such, it is important that you call omni::core::IObject::release() on the same pointer from which you called omni::core::IObject::acquire().

Do not directly use this method, rather use omni::core::ObjectPtr, which will manage calling omni::core::IObject::acquire() and omni::core::IObject::release() for you.

Thread Safety

This method is thread safe.

virtual void release_abi() noexcept = 0

Decrements the objects reference count.

Most implementations will destroy the object if the reference count reaches 0 (though this is not a requirement).

Objects may have multiple reference counts (e.g. one per interface implemented). As such, it is important that you call omni::core::IObject::release() on the same pointer from which you called omni::core::IObject::acquire().

Do not directly use this method, rather use omni::core::ObjectPtr, which will manage calling omni::core::IObject::acquire() and omni::core::IObject::release() for you.

Thread Safety

This method is thread safe.