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Copy pathpycapi_objimpl.h
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163 lines (133 loc) · 5.31 KB
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#ifndef Py_PYCAPI_MEM_H
#define Py_PYCAPI_MEM_H
#ifdef __cplusplus
extern "C" {
#endif
/*
* Raw object memory interface
* ===========================
*/
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03050000
PyAPI_FUNC(void *) PyObject_Calloc(size_t nelem, size_t elsize);
#endif
/*
* Generic object allocator interface
* ==================================
*/
#ifndef Py_LIMITED_API
/* This function returns the number of allocated memory blocks, regardless of size */
PyAPI_FUNC(Py_ssize_t) _Py_GetAllocatedBlocks(void);
#ifdef WITH_PYMALLOC
PyAPI_FUNC(int) _PyObject_DebugMallocStats(FILE *out);
#endif
typedef struct {
/* user context passed as the first argument to the 2 functions */
void *ctx;
/* allocate an arena of size bytes */
void* (*alloc) (void *ctx, size_t size);
/* free an arena */
void (*free) (void *ctx, void *ptr, size_t size);
} PyObjectArenaAllocator;
/* Get the arena allocator. */
PyAPI_FUNC(void) PyObject_GetArenaAllocator(PyObjectArenaAllocator *allocator);
/* Set the arena allocator. */
PyAPI_FUNC(void) PyObject_SetArenaAllocator(PyObjectArenaAllocator *allocator);
#endif /* !Py_LIMITED_API */
/*
* Garbage Collection Support
* ==========================
*/
#ifndef Py_LIMITED_API
PyAPI_FUNC(Py_ssize_t) _PyGC_CollectNoFail(void);
PyAPI_FUNC(Py_ssize_t) _PyGC_CollectIfEnabled(void);
/* Test if an object has a GC head */
#define PyObject_IS_GC(o) (PyType_IS_GC(Py_TYPE(o)) && \
(Py_TYPE(o)->tp_is_gc == NULL || Py_TYPE(o)->tp_is_gc(o)))
/* GC information is stored BEFORE the object structure. */
typedef struct {
// Pointer to next object in the list.
// 0 means the object is not tracked
uintptr_t _gc_next;
// Pointer to previous object in the list.
// Lowest two bits are used for flags documented later.
uintptr_t _gc_prev;
} PyGC_Head;
extern PyGC_Head *_PyGC_generation0;
#define _Py_AS_GC(o) ((PyGC_Head *)(o)-1)
/* Bit flags for _gc_prev */
/* Bit 0 is set when tp_finalize is called */
#define _PyGC_PREV_MASK_FINALIZED (1)
/* Bit 1 is set when the object is in generation which is GCed currently. */
#define _PyGC_PREV_MASK_COLLECTING (2)
/* The (N-2) most significant bits contain the real address. */
#define _PyGC_PREV_SHIFT (2)
#define _PyGC_PREV_MASK (((uintptr_t) -1) << _PyGC_PREV_SHIFT)
// Lowest bit of _gc_next is used for flags only in GC.
// But it is always 0 for normal code.
#define _PyGCHead_NEXT(g) ((PyGC_Head*)(g)->_gc_next)
#define _PyGCHead_SET_NEXT(g, p) ((g)->_gc_next = (uintptr_t)(p))
// Lowest two bits of _gc_prev is used for _PyGC_PREV_MASK_* flags.
#define _PyGCHead_PREV(g) ((PyGC_Head*)((g)->_gc_prev & _PyGC_PREV_MASK))
#define _PyGCHead_SET_PREV(g, p) do { \
assert(((uintptr_t)p & ~_PyGC_PREV_MASK) == 0); \
(g)->_gc_prev = ((g)->_gc_prev & ~_PyGC_PREV_MASK) \
| ((uintptr_t)(p)); \
} while (0)
#define _PyGCHead_FINALIZED(g) (((g)->_gc_prev & _PyGC_PREV_MASK_FINALIZED) != 0)
#define _PyGCHead_SET_FINALIZED(g) ((g)->_gc_prev |= _PyGC_PREV_MASK_FINALIZED)
#define _PyGC_FINALIZED(o) _PyGCHead_FINALIZED(_Py_AS_GC(o))
#define _PyGC_SET_FINALIZED(o) _PyGCHead_SET_FINALIZED(_Py_AS_GC(o))
/* Tell the GC to track this object.
*
* NB: While the object is tracked by the collector, it must be safe to call the
* ob_traverse method.
*
* Internal note: _PyGC_generation0->_gc_prev doesn't have any bit flags
* because it's not object header. So we don't use _PyGCHead_PREV() and
* _PyGCHead_SET_PREV() for it to avoid unnecessary bitwise operations.
*/
#define _PyObject_GC_TRACK(o) do { \
PyGC_Head *g = _Py_AS_GC(o); \
if (g->_gc_next != 0) { \
Py_FatalError("GC object already tracked"); \
} \
assert((g->_gc_prev & _PyGC_PREV_MASK_COLLECTING) == 0); \
PyGC_Head *last = (PyGC_Head*)(_PyGC_generation0->_gc_prev); \
_PyGCHead_SET_NEXT(last, g); \
_PyGCHead_SET_PREV(g, last); \
_PyGCHead_SET_NEXT(g, _PyGC_generation0); \
_PyGC_generation0->_gc_prev = (uintptr_t)g; \
} while (0);
/* Tell the GC to stop tracking this object.
*
* Internal note: This may be called while GC. So _PyGC_PREV_MASK_COLLECTING must
* be cleared. But _PyGC_PREV_MASK_FINALIZED bit is kept.
*/
#define _PyObject_GC_UNTRACK(o) do { \
PyGC_Head *g = _Py_AS_GC(o); \
PyGC_Head *prev = _PyGCHead_PREV(g); \
PyGC_Head *next = _PyGCHead_NEXT(g); \
assert(next != NULL); \
_PyGCHead_SET_NEXT(prev, next); \
_PyGCHead_SET_PREV(next, prev); \
g->_gc_next = 0; \
g->_gc_prev &= _PyGC_PREV_MASK_FINALIZED; \
} while (0);
/* True if the object is currently tracked by the GC. */
#define _PyObject_GC_IS_TRACKED(o) (_Py_AS_GC(o)->_gc_next != 0)
/* True if the object may be tracked by the GC in the future, or already is.
This can be useful to implement some optimizations. */
#define _PyObject_GC_MAY_BE_TRACKED(obj) \
(PyObject_IS_GC(obj) && \
(!PyTuple_CheckExact(obj) || _PyObject_GC_IS_TRACKED(obj)))
PyAPI_FUNC(PyObject *) _PyObject_GC_Malloc(size_t size);
PyAPI_FUNC(PyObject *) _PyObject_GC_Calloc(size_t size);
/* Test if a type supports weak references */
#define PyType_SUPPORTS_WEAKREFS(t) ((t)->tp_weaklistoffset > 0)
#define PyObject_GET_WEAKREFS_LISTPTR(o) \
((PyObject **) (((char *) (o)) + Py_TYPE(o)->tp_weaklistoffset))
#endif /* !Py_LIMITED_API */
#ifdef __cplusplus
}
#endif
#endif /* !Py_PYCAPI_MEM_H */