c10::DataPtr Class Reference

Public Member Functions
	DataPtr (void *data, Device device)
	DataPtr (void *data, void *ctx, DeleterFnPtr ctx_deleter, Device device)
void *	operator-> () const
void	clear ()
void *	get () const
void *	get_context () const
void *	release_context ()
std::unique_ptr< void, DeleterFnPtr > &&	move_context ()
	operator bool () const
template<typename T >
T *	cast_context (DeleterFnPtr expected_deleter) const
DeleterFnPtr	get_deleter () const
C10_NODISCARD bool	compare_exchange_deleter (DeleterFnPtr expected_deleter, DeleterFnPtr new_deleter)
	Compare the deleter in a DataPtr to expected_deleter. More...
Device	device () const
void	unsafe_set_device (Device device)

Detailed Description

Definition at line 19 of file Allocator.h.

Member Function Documentation

C10_NODISCARD bool c10::DataPtr::compare_exchange_deleter ( DeleterFnPtr  expected_deleter, DeleterFnPtr  new_deleter  )

inline

Compare the deleter in a DataPtr to expected_deleter.

If it matches, replace the deleter with new_deleter and return true; otherwise, does nothing and returns false.

In general, it is not safe to unconditionally set the deleter on a DataPtr, because you don't know what the deleter is, and thus will have a hard time properly disposing of the deleter without storing the original deleter (this is difficult to do, because DeleterFnPtr is not a closure, and because the context on DataPtr is only a single word, you generally don't have enough space to store both the original deleter and its context). However, in some cases, you know /exactly/ what the deleter is, and you have a new deleter that manually wraps the old one. In this case, you can safely swap the deleter after asserting that the deleters line up.

What are the requirements on new_deleter? It must still properly dispose of the void* pointer passed in as its argument, where void* is whatever the context of the original deleter is. So in general, you expect the new deleter to look something like this:

 [](void* ptr) {
   some_new_stuff(ptr);
   get_orig_allocator()->raw_deleter(ptr);
 }

Note that it won't work to close over the original allocator; you don't have enough space to do that! Also, it's unsafe to assume that the passed in pointer in question is the memory pointer in question; it might not be; be sure to read the source code of the Allocator in question to confirm this.

Definition at line 96 of file Allocator.h.

---

The documentation for this class was generated from the following file:

• c10/core/Allocator.h