cpython/Include/internal/pycore_object.h

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#ifndef Py_INTERNAL_OBJECT_H
#define Py_INTERNAL_OBJECT_H
#ifdef __cplusplus
extern "C" {
#endif
#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
# error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN defined"
#endif
#include "pycore_pystate.h" /* _PyRuntime */
/* 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: _PyRuntime.gc.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.
*
* The PyObject_GC_Track() function is the public version of this macro.
*/
static inline void _PyObject_GC_TRACK_impl(const char *filename, int lineno,
PyObject *op)
{
_PyObject_ASSERT_FROM(op, !_PyObject_GC_IS_TRACKED(op),
"object already tracked by the garbage collector",
filename, lineno, "_PyObject_GC_TRACK");
PyGC_Head *gc = _Py_AS_GC(op);
_PyObject_ASSERT_FROM(op,
(gc->_gc_prev & _PyGC_PREV_MASK_COLLECTING) == 0,
"object is in generation which is garbage collected",
filename, lineno, "_PyObject_GC_TRACK");
PyGC_Head *last = (PyGC_Head*)(_PyRuntime.gc.generation0->_gc_prev);
_PyGCHead_SET_NEXT(last, gc);
_PyGCHead_SET_PREV(gc, last);
_PyGCHead_SET_NEXT(gc, _PyRuntime.gc.generation0);
_PyRuntime.gc.generation0->_gc_prev = (uintptr_t)gc;
}
#define _PyObject_GC_TRACK(op) \
_PyObject_GC_TRACK_impl(__FILE__, __LINE__, _PyObject_CAST(op))
/* 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.
*
* The object must be tracked by the GC.
*
* The PyObject_GC_UnTrack() function is the public version of this macro.
*/
static inline void _PyObject_GC_UNTRACK_impl(const char *filename, int lineno,
PyObject *op)
{
_PyObject_ASSERT_FROM(op, _PyObject_GC_IS_TRACKED(op),
"object not tracked by the garbage collector",
filename, lineno, "_PyObject_GC_UNTRACK");
PyGC_Head *gc = _Py_AS_GC(op);
PyGC_Head *prev = _PyGCHead_PREV(gc);
PyGC_Head *next = _PyGCHead_NEXT(gc);
_PyGCHead_SET_NEXT(prev, next);
_PyGCHead_SET_PREV(next, prev);
gc->_gc_next = 0;
gc->_gc_prev &= _PyGC_PREV_MASK_FINALIZED;
}
#define _PyObject_GC_UNTRACK(op) \
_PyObject_GC_UNTRACK_impl(__FILE__, __LINE__, _PyObject_CAST(op))
#ifdef __cplusplus
}
#endif
#endif /* !Py_INTERNAL_OBJECT_H */