cpython/Include/internal/pycore_object.h

395 lines
13 KiB
C

#ifndef Py_INTERNAL_OBJECT_H
#define Py_INTERNAL_OBJECT_H
#ifdef __cplusplus
extern "C" {
#endif
#ifndef Py_BUILD_CORE
# error "this header requires Py_BUILD_CORE define"
#endif
#include <stdbool.h>
#include "pycore_gc.h" // _PyObject_GC_IS_TRACKED()
#include "pycore_interp.h" // PyInterpreterState.gc
#include "pycore_pystate.h" // _PyInterpreterState_GET()
#include "pycore_runtime.h" // _PyRuntime
/* This value provides *effective* immortality, meaning the object should never
be deallocated (until runtime finalization). See PEP 683 for more details about
immortality, as well as a proposed mechanism for proper immortality. */
#define _PyObject_IMMORTAL_REFCNT 999999999
#define _PyObject_IMMORTAL_INIT(type) \
{ \
.ob_refcnt = _PyObject_IMMORTAL_REFCNT, \
.ob_type = (type), \
}
#define _PyVarObject_IMMORTAL_INIT(type, size) \
{ \
.ob_base = _PyObject_IMMORTAL_INIT(type), \
.ob_size = size, \
}
PyAPI_FUNC(void) _Py_NO_RETURN _Py_FatalRefcountErrorFunc(
const char *func,
const char *message);
#define _Py_FatalRefcountError(message) \
_Py_FatalRefcountErrorFunc(__func__, (message))
// Increment reference count by n
static inline void _Py_RefcntAdd(PyObject* op, Py_ssize_t n)
{
#ifdef Py_REF_DEBUG
_Py_RefTotal += n;
#endif
op->ob_refcnt += n;
}
#define _Py_RefcntAdd(op, n) _Py_RefcntAdd(_PyObject_CAST(op), n)
static inline void
_Py_DECREF_SPECIALIZED(PyObject *op, const destructor destruct)
{
_Py_DECREF_STAT_INC();
#ifdef Py_REF_DEBUG
_Py_RefTotal--;
#endif
if (--op->ob_refcnt != 0) {
assert(op->ob_refcnt > 0);
}
else {
#ifdef Py_TRACE_REFS
_Py_ForgetReference(op);
#endif
destruct(op);
}
}
static inline void
_Py_DECREF_NO_DEALLOC(PyObject *op)
{
_Py_DECREF_STAT_INC();
#ifdef Py_REF_DEBUG
_Py_RefTotal--;
#endif
op->ob_refcnt--;
#ifdef Py_DEBUG
if (op->ob_refcnt <= 0) {
_Py_FatalRefcountError("Expected a positive remaining refcount");
}
#endif
}
PyAPI_FUNC(int) _PyType_CheckConsistency(PyTypeObject *type);
PyAPI_FUNC(int) _PyDict_CheckConsistency(PyObject *mp, int check_content);
/* Update the Python traceback of an object. This function must be called
when a memory block is reused from a free list.
Internal function called by _Py_NewReference(). */
extern int _PyTraceMalloc_NewReference(PyObject *op);
// Fast inlined version of PyType_HasFeature()
static inline int
_PyType_HasFeature(PyTypeObject *type, unsigned long feature) {
return ((type->tp_flags & feature) != 0);
}
extern void _PyType_InitCache(PyInterpreterState *interp);
/* Inline functions trading binary compatibility for speed:
_PyObject_Init() is the fast version of PyObject_Init(), and
_PyObject_InitVar() is the fast version of PyObject_InitVar().
These inline functions must not be called with op=NULL. */
static inline void
_PyObject_Init(PyObject *op, PyTypeObject *typeobj)
{
assert(op != NULL);
Py_SET_TYPE(op, typeobj);
if (_PyType_HasFeature(typeobj, Py_TPFLAGS_HEAPTYPE)) {
Py_INCREF(typeobj);
}
_Py_NewReference(op);
}
static inline void
_PyObject_InitVar(PyVarObject *op, PyTypeObject *typeobj, Py_ssize_t size)
{
assert(op != NULL);
Py_SET_SIZE(op, size);
_PyObject_Init((PyObject *)op, typeobj);
}
/* Tell the GC to track this object.
*
* The object must not be tracked by the GC.
*
* NB: While the object is tracked by the collector, it must be safe to call the
* ob_traverse method.
*
* Internal note: interp->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.
*
* See also the public PyObject_GC_Track() function.
*/
static inline void _PyObject_GC_TRACK(
// The preprocessor removes _PyObject_ASSERT_FROM() calls if NDEBUG is defined
#ifndef NDEBUG
const char *filename, int lineno,
#endif
PyObject *op)
{
_PyObject_ASSERT_FROM(op, !_PyObject_GC_IS_TRACKED(op),
"object already tracked by the garbage collector",
filename, lineno, __func__);
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, __func__);
PyInterpreterState *interp = _PyInterpreterState_GET();
PyGC_Head *generation0 = interp->gc.generation0;
PyGC_Head *last = (PyGC_Head*)(generation0->_gc_prev);
_PyGCHead_SET_NEXT(last, gc);
_PyGCHead_SET_PREV(gc, last);
_PyGCHead_SET_NEXT(gc, generation0);
generation0->_gc_prev = (uintptr_t)gc;
}
/* 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.
*
* See also the public PyObject_GC_UnTrack() which accept an object which is
* not tracked.
*/
static inline void _PyObject_GC_UNTRACK(
// The preprocessor removes _PyObject_ASSERT_FROM() calls if NDEBUG is defined
#ifndef NDEBUG
const char *filename, int lineno,
#endif
PyObject *op)
{
_PyObject_ASSERT_FROM(op, _PyObject_GC_IS_TRACKED(op),
"object not tracked by the garbage collector",
filename, lineno, __func__);
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;
}
// Macros to accept any type for the parameter, and to automatically pass
// the filename and the filename (if NDEBUG is not defined) where the macro
// is called.
#ifdef NDEBUG
# define _PyObject_GC_TRACK(op) \
_PyObject_GC_TRACK(_PyObject_CAST(op))
# define _PyObject_GC_UNTRACK(op) \
_PyObject_GC_UNTRACK(_PyObject_CAST(op))
#else
# define _PyObject_GC_TRACK(op) \
_PyObject_GC_TRACK(__FILE__, __LINE__, _PyObject_CAST(op))
# define _PyObject_GC_UNTRACK(op) \
_PyObject_GC_UNTRACK(__FILE__, __LINE__, _PyObject_CAST(op))
#endif
#ifdef Py_REF_DEBUG
extern void _PyDebug_PrintTotalRefs(void);
#endif
#ifdef Py_TRACE_REFS
extern void _Py_AddToAllObjects(PyObject *op, int force);
extern void _Py_PrintReferences(FILE *);
extern void _Py_PrintReferenceAddresses(FILE *);
#endif
/* Return the *address* of the object's weaklist. The address may be
* dereferenced to get the current head of the weaklist. This is useful
* for iterating over the linked list of weakrefs, especially when the
* list is being modified externally (e.g. refs getting removed).
*
* The returned pointer should not be used to change the head of the list
* nor should it be used to add, remove, or swap any refs in the list.
* That is the sole responsibility of the code in weakrefobject.c.
*/
static inline PyObject **
_PyObject_GET_WEAKREFS_LISTPTR(PyObject *op)
{
if (PyType_Check(op) &&
((PyTypeObject *)op)->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
static_builtin_state *state = _PyStaticType_GetState(
(PyTypeObject *)op);
return _PyStaticType_GET_WEAKREFS_LISTPTR(state);
}
// Essentially _PyObject_GET_WEAKREFS_LISTPTR_FROM_OFFSET():
Py_ssize_t offset = Py_TYPE(op)->tp_weaklistoffset;
return (PyObject **)((char *)op + offset);
}
/* This is a special case of _PyObject_GET_WEAKREFS_LISTPTR().
* Only the most fundamental lookup path is used.
* Consequently, static types should not be used.
*
* For static builtin types the returned pointer will always point
* to a NULL tp_weaklist. This is fine for any deallocation cases,
* since static types are never deallocated and static builtin types
* are only finalized at the end of runtime finalization.
*
* If the weaklist for static types is actually needed then use
* _PyObject_GET_WEAKREFS_LISTPTR().
*/
static inline PyWeakReference **
_PyObject_GET_WEAKREFS_LISTPTR_FROM_OFFSET(PyObject *op)
{
assert(!PyType_Check(op) ||
((PyTypeObject *)op)->tp_flags & Py_TPFLAGS_HEAPTYPE);
Py_ssize_t offset = Py_TYPE(op)->tp_weaklistoffset;
return (PyWeakReference **)((char *)op + offset);
}
// Fast inlined version of PyObject_IS_GC()
static inline int
_PyObject_IS_GC(PyObject *obj)
{
return (PyType_IS_GC(Py_TYPE(obj))
&& (Py_TYPE(obj)->tp_is_gc == NULL
|| Py_TYPE(obj)->tp_is_gc(obj)));
}
// Fast inlined version of PyType_IS_GC()
#define _PyType_IS_GC(t) _PyType_HasFeature((t), Py_TPFLAGS_HAVE_GC)
static inline size_t
_PyType_PreHeaderSize(PyTypeObject *tp)
{
return _PyType_IS_GC(tp) * sizeof(PyGC_Head) +
_PyType_HasFeature(tp, Py_TPFLAGS_PREHEADER) * 2 * sizeof(PyObject *);
}
void _PyObject_GC_Link(PyObject *op);
// Usage: assert(_Py_CheckSlotResult(obj, "__getitem__", result != NULL));
extern int _Py_CheckSlotResult(
PyObject *obj,
const char *slot_name,
int success);
// PyType_Ready() must be called if _PyType_IsReady() is false.
// See also the Py_TPFLAGS_READY flag.
#define _PyType_IsReady(type) ((type)->tp_dict != NULL)
// Test if a type supports weak references
static inline int _PyType_SUPPORTS_WEAKREFS(PyTypeObject *type) {
return (type->tp_weaklistoffset != 0);
}
extern PyObject* _PyType_AllocNoTrack(PyTypeObject *type, Py_ssize_t nitems);
extern int _PyObject_InitializeDict(PyObject *obj);
extern int _PyObject_StoreInstanceAttribute(PyObject *obj, PyDictValues *values,
PyObject *name, PyObject *value);
PyObject * _PyObject_GetInstanceAttribute(PyObject *obj, PyDictValues *values,
PyObject *name);
typedef union {
PyObject *dict;
/* Use a char* to generate a warning if directly assigning a PyDictValues */
char *values;
} PyDictOrValues;
static inline PyDictOrValues *
_PyObject_DictOrValuesPointer(PyObject *obj)
{
assert(Py_TYPE(obj)->tp_flags & Py_TPFLAGS_MANAGED_DICT);
return ((PyDictOrValues *)obj)-3;
}
static inline int
_PyDictOrValues_IsValues(PyDictOrValues dorv)
{
return ((uintptr_t)dorv.values) & 1;
}
static inline PyDictValues *
_PyDictOrValues_GetValues(PyDictOrValues dorv)
{
assert(_PyDictOrValues_IsValues(dorv));
return (PyDictValues *)(dorv.values + 1);
}
static inline PyObject *
_PyDictOrValues_GetDict(PyDictOrValues dorv)
{
assert(!_PyDictOrValues_IsValues(dorv));
return dorv.dict;
}
static inline void
_PyDictOrValues_SetValues(PyDictOrValues *ptr, PyDictValues *values)
{
ptr->values = ((char *)values) - 1;
}
#define MANAGED_WEAKREF_OFFSET (((Py_ssize_t)sizeof(PyObject *))*-4)
extern PyObject ** _PyObject_ComputedDictPointer(PyObject *);
extern void _PyObject_FreeInstanceAttributes(PyObject *obj);
extern int _PyObject_IsInstanceDictEmpty(PyObject *);
extern int _PyType_HasSubclasses(PyTypeObject *);
extern PyObject* _PyType_GetSubclasses(PyTypeObject *);
// Access macro to the members which are floating "behind" the object
static inline PyMemberDef* _PyHeapType_GET_MEMBERS(PyHeapTypeObject *etype) {
return (PyMemberDef*)((char*)etype + Py_TYPE(etype)->tp_basicsize);
}
PyAPI_FUNC(PyObject *) _PyObject_LookupSpecial(PyObject *, PyObject *);
/* C function call trampolines to mitigate bad function pointer casts.
*
* Typical native ABIs ignore additional arguments or fill in missing
* values with 0/NULL in function pointer cast. Compilers do not show
* warnings when a function pointer is explicitly casted to an
* incompatible type.
*
* Bad fpcasts are an issue in WebAssembly. WASM's indirect_call has strict
* function signature checks. Argument count, types, and return type must
* match.
*
* Third party code unintentionally rely on problematic fpcasts. The call
* trampoline mitigates common occurrences of bad fpcasts on Emscripten.
*/
#if defined(__EMSCRIPTEN__) && defined(PY_CALL_TRAMPOLINE)
#define _PyCFunction_TrampolineCall(meth, self, args) \
_PyCFunctionWithKeywords_TrampolineCall( \
(*(PyCFunctionWithKeywords)(void(*)(void))(meth)), (self), (args), NULL)
extern PyObject* _PyCFunctionWithKeywords_TrampolineCall(
PyCFunctionWithKeywords meth, PyObject *, PyObject *, PyObject *);
#else
#define _PyCFunction_TrampolineCall(meth, self, args) \
(meth)((self), (args))
#define _PyCFunctionWithKeywords_TrampolineCall(meth, self, args, kw) \
(meth)((self), (args), (kw))
#endif // __EMSCRIPTEN__ && PY_CALL_TRAMPOLINE
#ifdef __cplusplus
}
#endif
#endif /* !Py_INTERNAL_OBJECT_H */