1#ifndef Py_OBJECT_H
2#define Py_OBJECT_H
3#ifdef __cplusplus
4extern "C" {
5#endif
6
7
8/* Object and type object interface */
9
10/*
11Objects are structures allocated on the heap. Special rules apply to
12the use of objects to ensure they are properly garbage-collected.
13Objects are never allocated statically or on the stack; they must be
14accessed through special macros and functions only. (Type objects are
15exceptions to the first rule; the standard types are represented by
16statically initialized type objects, although work on type/class unification
17for Python 2.2 made it possible to have heap-allocated type objects too).
18
19An object has a 'reference count' that is increased or decreased when a
20pointer to the object is copied or deleted; when the reference count
21reaches zero there are no references to the object left and it can be
22removed from the heap.
23
24An object has a 'type' that determines what it represents and what kind
25of data it contains. An object's type is fixed when it is created.
26Types themselves are represented as objects; an object contains a
27pointer to the corresponding type object. The type itself has a type
28pointer pointing to the object representing the type 'type', which
29contains a pointer to itself!).
30
31Objects do not float around in memory; once allocated an object keeps
32the same size and address. Objects that must hold variable-size data
33can contain pointers to variable-size parts of the object. Not all
34objects of the same type have the same size; but the size cannot change
35after allocation. (These restrictions are made so a reference to an
36object can be simply a pointer -- moving an object would require
37updating all the pointers, and changing an object's size would require
38moving it if there was another object right next to it.)
39
40Objects are always accessed through pointers of the type 'PyObject *'.
41The type 'PyObject' is a structure that only contains the reference count
42and the type pointer. The actual memory allocated for an object
43contains other data that can only be accessed after casting the pointer
44to a pointer to a longer structure type. This longer type must start
45with the reference count and type fields; the macro PyObject_HEAD should be
46used for this (to accommodate for future changes). The implementation
47of a particular object type can cast the object pointer to the proper
48type and back.
49
50A standard interface exists for objects that contain an array of items
51whose size is determined when the object is allocated.
52*/
53
54/* Py_DEBUG implies Py_TRACE_REFS. */
55#if defined(Py_DEBUG) && !defined(Py_TRACE_REFS)
56#define Py_TRACE_REFS
57#endif
58
59/* Py_TRACE_REFS implies Py_REF_DEBUG. */
60#if defined(Py_TRACE_REFS) && !defined(Py_REF_DEBUG)
61#define Py_REF_DEBUG
62#endif
63
64#if defined(Py_LIMITED_API) && defined(Py_REF_DEBUG)
65#error Py_LIMITED_API is incompatible with Py_DEBUG, Py_TRACE_REFS, and Py_REF_DEBUG
66#endif
67
68
69#ifdef Py_TRACE_REFS
70/* Define pointers to support a doubly-linked list of all live heap objects. */
71#define _PyObject_HEAD_EXTRA \
72 struct _object *_ob_next; \
73 struct _object *_ob_prev;
74
75#define _PyObject_EXTRA_INIT 0, 0,
76
77#else
78#define _PyObject_HEAD_EXTRA
79#define _PyObject_EXTRA_INIT
80#endif
81
82/* PyObject_HEAD defines the initial segment of every PyObject. */
83#define PyObject_HEAD PyObject ob_base;
84
85#define PyObject_HEAD_INIT(type) \
86 { _PyObject_EXTRA_INIT \
87 1, type },
88
89#define PyVarObject_HEAD_INIT(type, size) \
90 { PyObject_HEAD_INIT(type) size },
91
92/* PyObject_VAR_HEAD defines the initial segment of all variable-size
93 * container objects. These end with a declaration of an array with 1
94 * element, but enough space is malloc'ed so that the array actually
95 * has room for ob_size elements. Note that ob_size is an element count,
96 * not necessarily a byte count.
97 */
98#define PyObject_VAR_HEAD PyVarObject ob_base;
99#define Py_INVALID_SIZE (Py_ssize_t)-1
100
101/* Nothing is actually declared to be a PyObject, but every pointer to
102 * a Python object can be cast to a PyObject*. This is inheritance built
103 * by hand. Similarly every pointer to a variable-size Python object can,
104 * in addition, be cast to PyVarObject*.
105 */
106typedef struct _object {
107 _PyObject_HEAD_EXTRA
108 Py_ssize_t ob_refcnt;
109 struct _typeobject *ob_type;
110} PyObject;
111
112typedef struct {
113 PyObject ob_base;
114 Py_ssize_t ob_size; /* Number of items in variable part */
115} PyVarObject;
116
117#define Py_REFCNT(ob) (((PyObject*)(ob))->ob_refcnt)
118#define Py_TYPE(ob) (((PyObject*)(ob))->ob_type)
119#define Py_SIZE(ob) (((PyVarObject*)(ob))->ob_size)
120
121/********************* String Literals ****************************************/
122/* This structure helps managing static strings. The basic usage goes like this:
123 Instead of doing
124
125 r = PyObject_CallMethod(o, "foo", "args", ...);
126
127 do
128
129 _Py_IDENTIFIER(foo);
130 ...
131 r = _PyObject_CallMethodId(o, &PyId_foo, "args", ...);
132
133 PyId_foo is a static variable, either on block level or file level. On first
134 usage, the string "foo" is interned, and the structures are linked. On interpreter
135 shutdown, all strings are released (through _PyUnicode_ClearStaticStrings).
136
137 Alternatively, _Py_static_string allows choosing the variable name.
138 _PyUnicode_FromId returns a borrowed reference to the interned string.
139 _PyObject_{Get,Set,Has}AttrId are __getattr__ versions using _Py_Identifier*.
140*/
141typedef struct _Py_Identifier {
142 struct _Py_Identifier *next;
143 const char* string;
144 PyObject *object;
145} _Py_Identifier;
146
147#define _Py_static_string_init(value) { 0, value, 0 }
148#define _Py_static_string(varname, value) static _Py_Identifier varname = _Py_static_string_init(value)
149#define _Py_IDENTIFIER(varname) _Py_static_string(PyId_##varname, #varname)
150
151/*
152Type objects contain a string containing the type name (to help somewhat
153in debugging), the allocation parameters (see PyObject_New() and
154PyObject_NewVar()),
155and methods for accessing objects of the type. Methods are optional, a
156nil pointer meaning that particular kind of access is not available for
157this type. The Py_DECREF() macro uses the tp_dealloc method without
158checking for a nil pointer; it should always be implemented except if
159the implementation can guarantee that the reference count will never
160reach zero (e.g., for statically allocated type objects).
161
162NB: the methods for certain type groups are now contained in separate
163method blocks.
164*/
165
166typedef PyObject * (*unaryfunc)(PyObject *);
167typedef PyObject * (*binaryfunc)(PyObject *, PyObject *);
168typedef PyObject * (*ternaryfunc)(PyObject *, PyObject *, PyObject *);
169typedef int (*inquiry)(PyObject *);
170typedef Py_ssize_t (*lenfunc)(PyObject *);
171typedef PyObject *(*ssizeargfunc)(PyObject *, Py_ssize_t);
172typedef PyObject *(*ssizessizeargfunc)(PyObject *, Py_ssize_t, Py_ssize_t);
173typedef int(*ssizeobjargproc)(PyObject *, Py_ssize_t, PyObject *);
174typedef int(*ssizessizeobjargproc)(PyObject *, Py_ssize_t, Py_ssize_t, PyObject *);
175typedef int(*objobjargproc)(PyObject *, PyObject *, PyObject *);
176
177#ifndef Py_LIMITED_API
178/* buffer interface */
179typedef struct bufferinfo {
180 void *buf;
181 PyObject *obj; /* owned reference */
182 Py_ssize_t len;
183 Py_ssize_t itemsize; /* This is Py_ssize_t so it can be
184 pointed to by strides in simple case.*/
185 int readonly;
186 int ndim;
187 char *format;
188 Py_ssize_t *shape;
189 Py_ssize_t *strides;
190 Py_ssize_t *suboffsets;
191 void *internal;
192} Py_buffer;
193
194typedef int (*getbufferproc)(PyObject *, Py_buffer *, int);
195typedef void (*releasebufferproc)(PyObject *, Py_buffer *);
196
197/* Maximum number of dimensions */
198#define PyBUF_MAX_NDIM 64
199
200/* Flags for getting buffers */
201#define PyBUF_SIMPLE 0
202#define PyBUF_WRITABLE 0x0001
203/* we used to include an E, backwards compatible alias */
204#define PyBUF_WRITEABLE PyBUF_WRITABLE
205#define PyBUF_FORMAT 0x0004
206#define PyBUF_ND 0x0008
207#define PyBUF_STRIDES (0x0010 | PyBUF_ND)
208#define PyBUF_C_CONTIGUOUS (0x0020 | PyBUF_STRIDES)
209#define PyBUF_F_CONTIGUOUS (0x0040 | PyBUF_STRIDES)
210#define PyBUF_ANY_CONTIGUOUS (0x0080 | PyBUF_STRIDES)
211#define PyBUF_INDIRECT (0x0100 | PyBUF_STRIDES)
212
213#define PyBUF_CONTIG (PyBUF_ND | PyBUF_WRITABLE)
214#define PyBUF_CONTIG_RO (PyBUF_ND)
215
216#define PyBUF_STRIDED (PyBUF_STRIDES | PyBUF_WRITABLE)
217#define PyBUF_STRIDED_RO (PyBUF_STRIDES)
218
219#define PyBUF_RECORDS (PyBUF_STRIDES | PyBUF_WRITABLE | PyBUF_FORMAT)
220#define PyBUF_RECORDS_RO (PyBUF_STRIDES | PyBUF_FORMAT)
221
222#define PyBUF_FULL (PyBUF_INDIRECT | PyBUF_WRITABLE | PyBUF_FORMAT)
223#define PyBUF_FULL_RO (PyBUF_INDIRECT | PyBUF_FORMAT)
224
225
226#define PyBUF_READ 0x100
227#define PyBUF_WRITE 0x200
228
229/* End buffer interface */
230#endif /* Py_LIMITED_API */
231
232typedef int (*objobjproc)(PyObject *, PyObject *);
233typedef int (*visitproc)(PyObject *, void *);
234typedef int (*traverseproc)(PyObject *, visitproc, void *);
235
236#ifndef Py_LIMITED_API
237typedef struct {
238 /* Number implementations must check *both*
239 arguments for proper type and implement the necessary conversions
240 in the slot functions themselves. */
241
242 binaryfunc nb_add;
243 binaryfunc nb_subtract;
244 binaryfunc nb_multiply;
245 binaryfunc nb_remainder;
246 binaryfunc nb_divmod;
247 ternaryfunc nb_power;
248 unaryfunc nb_negative;
249 unaryfunc nb_positive;
250 unaryfunc nb_absolute;
251 inquiry nb_bool;
252 unaryfunc nb_invert;
253 binaryfunc nb_lshift;
254 binaryfunc nb_rshift;
255 binaryfunc nb_and;
256 binaryfunc nb_xor;
257 binaryfunc nb_or;
258 unaryfunc nb_int;
259 void *nb_reserved; /* the slot formerly known as nb_long */
260 unaryfunc nb_float;
261
262 binaryfunc nb_inplace_add;
263 binaryfunc nb_inplace_subtract;
264 binaryfunc nb_inplace_multiply;
265 binaryfunc nb_inplace_remainder;
266 ternaryfunc nb_inplace_power;
267 binaryfunc nb_inplace_lshift;
268 binaryfunc nb_inplace_rshift;
269 binaryfunc nb_inplace_and;
270 binaryfunc nb_inplace_xor;
271 binaryfunc nb_inplace_or;
272
273 binaryfunc nb_floor_divide;
274 binaryfunc nb_true_divide;
275 binaryfunc nb_inplace_floor_divide;
276 binaryfunc nb_inplace_true_divide;
277
278 unaryfunc nb_index;
279
280 binaryfunc nb_matrix_multiply;
281 binaryfunc nb_inplace_matrix_multiply;
282} PyNumberMethods;
283
284typedef struct {
285 lenfunc sq_length;
286 binaryfunc sq_concat;
287 ssizeargfunc sq_repeat;
288 ssizeargfunc sq_item;
289 void *was_sq_slice;
290 ssizeobjargproc sq_ass_item;
291 void *was_sq_ass_slice;
292 objobjproc sq_contains;
293
294 binaryfunc sq_inplace_concat;
295 ssizeargfunc sq_inplace_repeat;
296} PySequenceMethods;
297
298typedef struct {
299 lenfunc mp_length;
300 binaryfunc mp_subscript;
301 objobjargproc mp_ass_subscript;
302} PyMappingMethods;
303
304typedef struct {
305 unaryfunc am_await;
306 unaryfunc am_aiter;
307 unaryfunc am_anext;
308} PyAsyncMethods;
309
310typedef struct {
311 getbufferproc bf_getbuffer;
312 releasebufferproc bf_releasebuffer;
313} PyBufferProcs;
314#endif /* Py_LIMITED_API */
315
316typedef void (*freefunc)(void *);
317typedef void (*destructor)(PyObject *);
318#ifndef Py_LIMITED_API
319/* We can't provide a full compile-time check that limited-API
320 users won't implement tp_print. However, not defining printfunc
321 and making tp_print of a different function pointer type
322 should at least cause a warning in most cases. */
323typedef int (*printfunc)(PyObject *, FILE *, int);
324#endif
325typedef PyObject *(*getattrfunc)(PyObject *, char *);
326typedef PyObject *(*getattrofunc)(PyObject *, PyObject *);
327typedef int (*setattrfunc)(PyObject *, char *, PyObject *);
328typedef int (*setattrofunc)(PyObject *, PyObject *, PyObject *);
329typedef PyObject *(*reprfunc)(PyObject *);
330typedef Py_hash_t (*hashfunc)(PyObject *);
331typedef PyObject *(*richcmpfunc) (PyObject *, PyObject *, int);
332typedef PyObject *(*getiterfunc) (PyObject *);
333typedef PyObject *(*iternextfunc) (PyObject *);
334typedef PyObject *(*descrgetfunc) (PyObject *, PyObject *, PyObject *);
335typedef int (*descrsetfunc) (PyObject *, PyObject *, PyObject *);
336typedef int (*initproc)(PyObject *, PyObject *, PyObject *);
337typedef PyObject *(*newfunc)(struct _typeobject *, PyObject *, PyObject *);
338typedef PyObject *(*allocfunc)(struct _typeobject *, Py_ssize_t);
339
340#ifdef Py_LIMITED_API
341typedef struct _typeobject PyTypeObject; /* opaque */
342#else
343typedef struct _typeobject {
344 PyObject_VAR_HEAD
345 const char *tp_name; /* For printing, in format "<module>.<name>" */
346 Py_ssize_t tp_basicsize, tp_itemsize; /* For allocation */
347
348 /* Methods to implement standard operations */
349
350 destructor tp_dealloc;
351 printfunc tp_print;
352 getattrfunc tp_getattr;
353 setattrfunc tp_setattr;
354 PyAsyncMethods *tp_as_async; /* formerly known as tp_compare (Python 2)
355 or tp_reserved (Python 3) */
356 reprfunc tp_repr;
357
358 /* Method suites for standard classes */
359
360 PyNumberMethods *tp_as_number;
361 PySequenceMethods *tp_as_sequence;
362 PyMappingMethods *tp_as_mapping;
363
364 /* More standard operations (here for binary compatibility) */
365
366 hashfunc tp_hash;
367 ternaryfunc tp_call;
368 reprfunc tp_str;
369 getattrofunc tp_getattro;
370 setattrofunc tp_setattro;
371
372 /* Functions to access object as input/output buffer */
373 PyBufferProcs *tp_as_buffer;
374
375 /* Flags to define presence of optional/expanded features */
376 unsigned long tp_flags;
377
378 const char *tp_doc; /* Documentation string */
379
380 /* Assigned meaning in release 2.0 */
381 /* call function for all accessible objects */
382 traverseproc tp_traverse;
383
384 /* delete references to contained objects */
385 inquiry tp_clear;
386
387 /* Assigned meaning in release 2.1 */
388 /* rich comparisons */
389 richcmpfunc tp_richcompare;
390
391 /* weak reference enabler */
392 Py_ssize_t tp_weaklistoffset;
393
394 /* Iterators */
395 getiterfunc tp_iter;
396 iternextfunc tp_iternext;
397
398 /* Attribute descriptor and subclassing stuff */
399 struct PyMethodDef *tp_methods;
400 struct PyMemberDef *tp_members;
401 struct PyGetSetDef *tp_getset;
402 struct _typeobject *tp_base;
403 PyObject *tp_dict;
404 descrgetfunc tp_descr_get;
405 descrsetfunc tp_descr_set;
406 Py_ssize_t tp_dictoffset;
407 initproc tp_init;
408 allocfunc tp_alloc;
409 newfunc tp_new;
410 freefunc tp_free; /* Low-level free-memory routine */
411 inquiry tp_is_gc; /* For PyObject_IS_GC */
412 PyObject *tp_bases;
413 PyObject *tp_mro; /* method resolution order */
414 PyObject *tp_cache;
415 PyObject *tp_subclasses;
416 PyObject *tp_weaklist;
417 destructor tp_del;
418
419 /* Type attribute cache version tag. Added in version 2.6 */
420 unsigned int tp_version_tag;
421
422 destructor tp_finalize;
423
424#ifdef COUNT_ALLOCS
425 /* these must be last and never explicitly initialized */
426 Py_ssize_t tp_allocs;
427 Py_ssize_t tp_frees;
428 Py_ssize_t tp_maxalloc;
429 struct _typeobject *tp_prev;
430 struct _typeobject *tp_next;
431#endif
432} PyTypeObject;
433#endif
434
435typedef struct{
436 int slot; /* slot id, see below */
437 void *pfunc; /* function pointer */
438} PyType_Slot;
439
440typedef struct{
441 const char* name;
442 int basicsize;
443 int itemsize;
444 unsigned int flags;
445 PyType_Slot *slots; /* terminated by slot==0. */
446} PyType_Spec;
447
448PyAPI_FUNC(PyObject*) PyType_FromSpec(PyType_Spec*);
449#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03030000
450PyAPI_FUNC(PyObject*) PyType_FromSpecWithBases(PyType_Spec*, PyObject*);
451#endif
452#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03040000
453PyAPI_FUNC(void*) PyType_GetSlot(PyTypeObject*, int);
454#endif
455
456#ifndef Py_LIMITED_API
457/* The *real* layout of a type object when allocated on the heap */
458typedef struct _heaptypeobject {
459 /* Note: there's a dependency on the order of these members
460 in slotptr() in typeobject.c . */
461 PyTypeObject ht_type;
462 PyAsyncMethods as_async;
463 PyNumberMethods as_number;
464 PyMappingMethods as_mapping;
465 PySequenceMethods as_sequence; /* as_sequence comes after as_mapping,
466 so that the mapping wins when both
467 the mapping and the sequence define
468 a given operator (e.g. __getitem__).
469 see add_operators() in typeobject.c . */
470 PyBufferProcs as_buffer;
471 PyObject *ht_name, *ht_slots, *ht_qualname;
472 struct _dictkeysobject *ht_cached_keys;
473 /* here are optional user slots, followed by the members. */
474} PyHeapTypeObject;
475
476/* access macro to the members which are floating "behind" the object */
477#define PyHeapType_GET_MEMBERS(etype) \
478 ((PyMemberDef *)(((char *)etype) + Py_TYPE(etype)->tp_basicsize))
479#endif
480
481/* Generic type check */
482PyAPI_FUNC(int) PyType_IsSubtype(PyTypeObject *, PyTypeObject *);
483#define PyObject_TypeCheck(ob, tp) \
484 (Py_TYPE(ob) == (tp) || PyType_IsSubtype(Py_TYPE(ob), (tp)))
485
486PyAPI_DATA(PyTypeObject) PyType_Type; /* built-in 'type' */
487PyAPI_DATA(PyTypeObject) PyBaseObject_Type; /* built-in 'object' */
488PyAPI_DATA(PyTypeObject) PySuper_Type; /* built-in 'super' */
489
490PyAPI_FUNC(unsigned long) PyType_GetFlags(PyTypeObject*);
491
492#define PyType_Check(op) \
493 PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_TYPE_SUBCLASS)
494#define PyType_CheckExact(op) (Py_TYPE(op) == &PyType_Type)
495
496PyAPI_FUNC(int) PyType_Ready(PyTypeObject *);
497PyAPI_FUNC(PyObject *) PyType_GenericAlloc(PyTypeObject *, Py_ssize_t);
498PyAPI_FUNC(PyObject *) PyType_GenericNew(PyTypeObject *,
499 PyObject *, PyObject *);
500#ifndef Py_LIMITED_API
501PyAPI_FUNC(PyObject *) _PyType_Lookup(PyTypeObject *, PyObject *);
502PyAPI_FUNC(PyObject *) _PyType_LookupId(PyTypeObject *, _Py_Identifier *);
503PyAPI_FUNC(PyObject *) _PyObject_LookupSpecial(PyObject *, _Py_Identifier *);
504PyAPI_FUNC(PyTypeObject *) _PyType_CalculateMetaclass(PyTypeObject *, PyObject *);
505#endif
506PyAPI_FUNC(unsigned int) PyType_ClearCache(void);
507PyAPI_FUNC(void) PyType_Modified(PyTypeObject *);
508
509#ifndef Py_LIMITED_API
510PyAPI_FUNC(PyObject *) _PyType_GetDocFromInternalDoc(const char *, const char *);
511PyAPI_FUNC(PyObject *) _PyType_GetTextSignatureFromInternalDoc(const char *, const char *);
512#endif
513
514/* Generic operations on objects */
515struct _Py_Identifier;
516#ifndef Py_LIMITED_API
517PyAPI_FUNC(int) PyObject_Print(PyObject *, FILE *, int);
518PyAPI_FUNC(void) _Py_BreakPoint(void);
519PyAPI_FUNC(void) _PyObject_Dump(PyObject *);
520#endif
521PyAPI_FUNC(PyObject *) PyObject_Repr(PyObject *);
522PyAPI_FUNC(PyObject *) PyObject_Str(PyObject *);
523PyAPI_FUNC(PyObject *) PyObject_ASCII(PyObject *);
524PyAPI_FUNC(PyObject *) PyObject_Bytes(PyObject *);
525PyAPI_FUNC(PyObject *) PyObject_RichCompare(PyObject *, PyObject *, int);
526PyAPI_FUNC(int) PyObject_RichCompareBool(PyObject *, PyObject *, int);
527PyAPI_FUNC(PyObject *) PyObject_GetAttrString(PyObject *, const char *);
528PyAPI_FUNC(int) PyObject_SetAttrString(PyObject *, const char *, PyObject *);
529PyAPI_FUNC(int) PyObject_HasAttrString(PyObject *, const char *);
530PyAPI_FUNC(PyObject *) PyObject_GetAttr(PyObject *, PyObject *);
531PyAPI_FUNC(int) PyObject_SetAttr(PyObject *, PyObject *, PyObject *);
532PyAPI_FUNC(int) PyObject_HasAttr(PyObject *, PyObject *);
533PyAPI_FUNC(int) _PyObject_IsAbstract(PyObject *);
534PyAPI_FUNC(PyObject *) _PyObject_GetAttrId(PyObject *, struct _Py_Identifier *);
535PyAPI_FUNC(int) _PyObject_SetAttrId(PyObject *, struct _Py_Identifier *, PyObject *);
536PyAPI_FUNC(int) _PyObject_HasAttrId(PyObject *, struct _Py_Identifier *);
537#ifndef Py_LIMITED_API
538PyAPI_FUNC(PyObject **) _PyObject_GetDictPtr(PyObject *);
539#endif
540PyAPI_FUNC(PyObject *) PyObject_SelfIter(PyObject *);
541#ifndef Py_LIMITED_API
542PyAPI_FUNC(PyObject *) _PyObject_NextNotImplemented(PyObject *);
543#endif
544PyAPI_FUNC(PyObject *) PyObject_GenericGetAttr(PyObject *, PyObject *);
545PyAPI_FUNC(int) PyObject_GenericSetAttr(PyObject *,
546 PyObject *, PyObject *);
547PyAPI_FUNC(int) PyObject_GenericSetDict(PyObject *, PyObject *, void *);
548PyAPI_FUNC(Py_hash_t) PyObject_Hash(PyObject *);
549PyAPI_FUNC(Py_hash_t) PyObject_HashNotImplemented(PyObject *);
550PyAPI_FUNC(int) PyObject_IsTrue(PyObject *);
551PyAPI_FUNC(int) PyObject_Not(PyObject *);
552PyAPI_FUNC(int) PyCallable_Check(PyObject *);
553
554PyAPI_FUNC(void) PyObject_ClearWeakRefs(PyObject *);
555#ifndef Py_LIMITED_API
556PyAPI_FUNC(void) PyObject_CallFinalizer(PyObject *);
557PyAPI_FUNC(int) PyObject_CallFinalizerFromDealloc(PyObject *);
558#endif
559
560/* Same as PyObject_Generic{Get,Set}Attr, but passing the attributes
561 dict as the last parameter. */
562PyAPI_FUNC(PyObject *)
563_PyObject_GenericGetAttrWithDict(PyObject *, PyObject *, PyObject *);
564PyAPI_FUNC(int)
565_PyObject_GenericSetAttrWithDict(PyObject *, PyObject *,
566 PyObject *, PyObject *);
567
568/* Helper to look up a builtin object */
569#ifndef Py_LIMITED_API
570PyAPI_FUNC(PyObject *)
571_PyObject_GetBuiltin(const char *name);
572#endif
573
574/* PyObject_Dir(obj) acts like Python builtins.dir(obj), returning a
575 list of strings. PyObject_Dir(NULL) is like builtins.dir(),
576 returning the names of the current locals. In this case, if there are
577 no current locals, NULL is returned, and PyErr_Occurred() is false.
578*/
579PyAPI_FUNC(PyObject *) PyObject_Dir(PyObject *);
580
581
582/* Helpers for printing recursive container types */
583PyAPI_FUNC(int) Py_ReprEnter(PyObject *);
584PyAPI_FUNC(void) Py_ReprLeave(PyObject *);
585
586/* Flag bits for printing: */
587#define Py_PRINT_RAW 1 /* No string quotes etc. */
588
589/*
590`Type flags (tp_flags)
591
592These flags are used to extend the type structure in a backwards-compatible
593fashion. Extensions can use the flags to indicate (and test) when a given
594type structure contains a new feature. The Python core will use these when
595introducing new functionality between major revisions (to avoid mid-version
596changes in the PYTHON_API_VERSION).
597
598Arbitration of the flag bit positions will need to be coordinated among
599all extension writers who publically release their extensions (this will
600be fewer than you might expect!)..
601
602Most flags were removed as of Python 3.0 to make room for new flags. (Some
603flags are not for backwards compatibility but to indicate the presence of an
604optional feature; these flags remain of course.)
605
606Type definitions should use Py_TPFLAGS_DEFAULT for their tp_flags value.
607
608Code can use PyType_HasFeature(type_ob, flag_value) to test whether the
609given type object has a specified feature.
610*/
611
612/* Set if the type object is dynamically allocated */
613#define Py_TPFLAGS_HEAPTYPE (1UL << 9)
614
615/* Set if the type allows subclassing */
616#define Py_TPFLAGS_BASETYPE (1UL << 10)
617
618/* Set if the type is 'ready' -- fully initialized */
619#define Py_TPFLAGS_READY (1UL << 12)
620
621/* Set while the type is being 'readied', to prevent recursive ready calls */
622#define Py_TPFLAGS_READYING (1UL << 13)
623
624/* Objects support garbage collection (see objimp.h) */
625#define Py_TPFLAGS_HAVE_GC (1UL << 14)
626
627/* These two bits are preserved for Stackless Python, next after this is 17 */
628#ifdef STACKLESS
629#define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION (3UL << 15)
630#else
631#define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION 0
632#endif
633
634/* Objects support type attribute cache */
635#define Py_TPFLAGS_HAVE_VERSION_TAG (1UL << 18)
636#define Py_TPFLAGS_VALID_VERSION_TAG (1UL << 19)
637
638/* Type is abstract and cannot be instantiated */
639#define Py_TPFLAGS_IS_ABSTRACT (1UL << 20)
640
641/* These flags are used to determine if a type is a subclass. */
642#define Py_TPFLAGS_LONG_SUBCLASS (1UL << 24)
643#define Py_TPFLAGS_LIST_SUBCLASS (1UL << 25)
644#define Py_TPFLAGS_TUPLE_SUBCLASS (1UL << 26)
645#define Py_TPFLAGS_BYTES_SUBCLASS (1UL << 27)
646#define Py_TPFLAGS_UNICODE_SUBCLASS (1UL << 28)
647#define Py_TPFLAGS_DICT_SUBCLASS (1UL << 29)
648#define Py_TPFLAGS_BASE_EXC_SUBCLASS (1UL << 30)
649#define Py_TPFLAGS_TYPE_SUBCLASS (1UL << 31)
650
651#define Py_TPFLAGS_DEFAULT ( \
652 Py_TPFLAGS_HAVE_STACKLESS_EXTENSION | \
653 Py_TPFLAGS_HAVE_VERSION_TAG | \
654 0)
655
656/* NOTE: The following flags reuse lower bits (removed as part of the
657 * Python 3.0 transition). */
658
659/* Type structure has tp_finalize member (3.4) */
660#define Py_TPFLAGS_HAVE_FINALIZE (1UL << 0)
661
662#ifdef Py_LIMITED_API
663#define PyType_HasFeature(t,f) ((PyType_GetFlags(t) & (f)) != 0)
664#else
665#define PyType_HasFeature(t,f) (((t)->tp_flags & (f)) != 0)
666#endif
667#define PyType_FastSubclass(t,f) PyType_HasFeature(t,f)
668
669
670/*
671The macros Py_INCREF(op) and Py_DECREF(op) are used to increment or decrement
672reference counts. Py_DECREF calls the object's deallocator function when
673the refcount falls to 0; for
674objects that don't contain references to other objects or heap memory
675this can be the standard function free(). Both macros can be used
676wherever a void expression is allowed. The argument must not be a
677NULL pointer. If it may be NULL, use Py_XINCREF/Py_XDECREF instead.
678The macro _Py_NewReference(op) initialize reference counts to 1, and
679in special builds (Py_REF_DEBUG, Py_TRACE_REFS) performs additional
680bookkeeping appropriate to the special build.
681
682We assume that the reference count field can never overflow; this can
683be proven when the size of the field is the same as the pointer size, so
684we ignore the possibility. Provided a C int is at least 32 bits (which
685is implicitly assumed in many parts of this code), that's enough for
686about 2**31 references to an object.
687
688XXX The following became out of date in Python 2.2, but I'm not sure
689XXX what the full truth is now. Certainly, heap-allocated type objects
690XXX can and should be deallocated.
691Type objects should never be deallocated; the type pointer in an object
692is not considered to be a reference to the type object, to save
693complications in the deallocation function. (This is actually a
694decision that's up to the implementer of each new type so if you want,
695you can count such references to the type object.)
696*/
697
698/* First define a pile of simple helper macros, one set per special
699 * build symbol. These either expand to the obvious things, or to
700 * nothing at all when the special mode isn't in effect. The main
701 * macros can later be defined just once then, yet expand to different
702 * things depending on which special build options are and aren't in effect.
703 * Trust me <wink>: while painful, this is 20x easier to understand than,
704 * e.g, defining _Py_NewReference five different times in a maze of nested
705 * #ifdefs (we used to do that -- it was impenetrable).
706 */
707#ifdef Py_REF_DEBUG
708PyAPI_DATA(Py_ssize_t) _Py_RefTotal;
709PyAPI_FUNC(void) _Py_NegativeRefcount(const char *fname,
710 int lineno, PyObject *op);
711PyAPI_FUNC(PyObject *) _PyDict_Dummy(void);
712PyAPI_FUNC(Py_ssize_t) _Py_GetRefTotal(void);
713#define _Py_INC_REFTOTAL _Py_RefTotal++
714#define _Py_DEC_REFTOTAL _Py_RefTotal--
715#define _Py_REF_DEBUG_COMMA ,
716#define _Py_CHECK_REFCNT(OP) \
717{ if (((PyObject*)OP)->ob_refcnt < 0) \
718 _Py_NegativeRefcount(__FILE__, __LINE__, \
719 (PyObject *)(OP)); \
720}
721/* Py_REF_DEBUG also controls the display of refcounts and memory block
722 * allocations at the interactive prompt and at interpreter shutdown
723 */
724PyAPI_FUNC(void) _PyDebug_PrintTotalRefs(void);
725#define _PY_DEBUG_PRINT_TOTAL_REFS() _PyDebug_PrintTotalRefs()
726#else
727#define _Py_INC_REFTOTAL
728#define _Py_DEC_REFTOTAL
729#define _Py_REF_DEBUG_COMMA
730#define _Py_CHECK_REFCNT(OP) /* a semicolon */;
731#define _PY_DEBUG_PRINT_TOTAL_REFS()
732#endif /* Py_REF_DEBUG */
733
734#ifdef COUNT_ALLOCS
735PyAPI_FUNC(void) inc_count(PyTypeObject *);
736PyAPI_FUNC(void) dec_count(PyTypeObject *);
737#define _Py_INC_TPALLOCS(OP) inc_count(Py_TYPE(OP))
738#define _Py_INC_TPFREES(OP) dec_count(Py_TYPE(OP))
739#define _Py_DEC_TPFREES(OP) Py_TYPE(OP)->tp_frees--
740#define _Py_COUNT_ALLOCS_COMMA ,
741#else
742#define _Py_INC_TPALLOCS(OP)
743#define _Py_INC_TPFREES(OP)
744#define _Py_DEC_TPFREES(OP)
745#define _Py_COUNT_ALLOCS_COMMA
746#endif /* COUNT_ALLOCS */
747
748#ifdef Py_TRACE_REFS
749/* Py_TRACE_REFS is such major surgery that we call external routines. */
750PyAPI_FUNC(void) _Py_NewReference(PyObject *);
751PyAPI_FUNC(void) _Py_ForgetReference(PyObject *);
752PyAPI_FUNC(void) _Py_Dealloc(PyObject *);
753PyAPI_FUNC(void) _Py_PrintReferences(FILE *);
754PyAPI_FUNC(void) _Py_PrintReferenceAddresses(FILE *);
755PyAPI_FUNC(void) _Py_AddToAllObjects(PyObject *, int force);
756
757#else
758/* Without Py_TRACE_REFS, there's little enough to do that we expand code
759 * inline.
760 */
761#define _Py_NewReference(op) ( \
762 _Py_INC_TPALLOCS(op) _Py_COUNT_ALLOCS_COMMA \
763 _Py_INC_REFTOTAL _Py_REF_DEBUG_COMMA \
764 Py_REFCNT(op) = 1)
765
766#define _Py_ForgetReference(op) _Py_INC_TPFREES(op)
767
768#ifdef Py_LIMITED_API
769PyAPI_FUNC(void) _Py_Dealloc(PyObject *);
770#else
771#define _Py_Dealloc(op) ( \
772 _Py_INC_TPFREES(op) _Py_COUNT_ALLOCS_COMMA \
773 (*Py_TYPE(op)->tp_dealloc)((PyObject *)(op)))
774#endif
775#endif /* !Py_TRACE_REFS */
776
777#define Py_INCREF(op) ( \
778 _Py_INC_REFTOTAL _Py_REF_DEBUG_COMMA \
779 ((PyObject *)(op))->ob_refcnt++)
780
781#define Py_DECREF(op) \
782 do { \
783 PyObject *_py_decref_tmp = (PyObject *)(op); \
784 if (_Py_DEC_REFTOTAL _Py_REF_DEBUG_COMMA \
785 --(_py_decref_tmp)->ob_refcnt != 0) \
786 _Py_CHECK_REFCNT(_py_decref_tmp) \
787 else \
788 _Py_Dealloc(_py_decref_tmp); \
789 } while (0)
790
791/* Safely decref `op` and set `op` to NULL, especially useful in tp_clear
792 * and tp_dealloc implementations.
793 *
794 * Note that "the obvious" code can be deadly:
795 *
796 * Py_XDECREF(op);
797 * op = NULL;
798 *
799 * Typically, `op` is something like self->containee, and `self` is done
800 * using its `containee` member. In the code sequence above, suppose
801 * `containee` is non-NULL with a refcount of 1. Its refcount falls to
802 * 0 on the first line, which can trigger an arbitrary amount of code,
803 * possibly including finalizers (like __del__ methods or weakref callbacks)
804 * coded in Python, which in turn can release the GIL and allow other threads
805 * to run, etc. Such code may even invoke methods of `self` again, or cause
806 * cyclic gc to trigger, but-- oops! --self->containee still points to the
807 * object being torn down, and it may be in an insane state while being torn
808 * down. This has in fact been a rich historic source of miserable (rare &
809 * hard-to-diagnose) segfaulting (and other) bugs.
810 *
811 * The safe way is:
812 *
813 * Py_CLEAR(op);
814 *
815 * That arranges to set `op` to NULL _before_ decref'ing, so that any code
816 * triggered as a side-effect of `op` getting torn down no longer believes
817 * `op` points to a valid object.
818 *
819 * There are cases where it's safe to use the naive code, but they're brittle.
820 * For example, if `op` points to a Python integer, you know that destroying
821 * one of those can't cause problems -- but in part that relies on that
822 * Python integers aren't currently weakly referencable. Best practice is
823 * to use Py_CLEAR() even if you can't think of a reason for why you need to.
824 */
825#define Py_CLEAR(op) \
826 do { \
827 PyObject *_py_tmp = (PyObject *)(op); \
828 if (_py_tmp != NULL) { \
829 (op) = NULL; \
830 Py_DECREF(_py_tmp); \
831 } \
832 } while (0)
833
834/* Macros to use in case the object pointer may be NULL: */
835#define Py_XINCREF(op) \
836 do { \
837 PyObject *_py_xincref_tmp = (PyObject *)(op); \
838 if (_py_xincref_tmp != NULL) \
839 Py_INCREF(_py_xincref_tmp); \
840 } while (0)
841
842#define Py_XDECREF(op) \
843 do { \
844 PyObject *_py_xdecref_tmp = (PyObject *)(op); \
845 if (_py_xdecref_tmp != NULL) \
846 Py_DECREF(_py_xdecref_tmp); \
847 } while (0)
848
849#ifndef Py_LIMITED_API
850/* Safely decref `op` and set `op` to `op2`.
851 *
852 * As in case of Py_CLEAR "the obvious" code can be deadly:
853 *
854 * Py_DECREF(op);
855 * op = op2;
856 *
857 * The safe way is:
858 *
859 * Py_SETREF(op, op2);
860 *
861 * That arranges to set `op` to `op2` _before_ decref'ing, so that any code
862 * triggered as a side-effect of `op` getting torn down no longer believes
863 * `op` points to a valid object.
864 *
865 * Py_XSETREF is a variant of Py_SETREF that uses Py_XDECREF instead of
866 * Py_DECREF.
867 */
868
869#define Py_SETREF(op, op2) \
870 do { \
871 PyObject *_py_tmp = (PyObject *)(op); \
872 (op) = (op2); \
873 Py_DECREF(_py_tmp); \
874 } while (0)
875
876#define Py_XSETREF(op, op2) \
877 do { \
878 PyObject *_py_tmp = (PyObject *)(op); \
879 (op) = (op2); \
880 Py_XDECREF(_py_tmp); \
881 } while (0)
882
883#endif /* ifndef Py_LIMITED_API */
884
885/*
886These are provided as conveniences to Python runtime embedders, so that
887they can have object code that is not dependent on Python compilation flags.
888*/
889PyAPI_FUNC(void) Py_IncRef(PyObject *);
890PyAPI_FUNC(void) Py_DecRef(PyObject *);
891
892PyAPI_DATA(PyTypeObject) _PyNone_Type;
893PyAPI_DATA(PyTypeObject) _PyNotImplemented_Type;
894
895/*
896_Py_NoneStruct is an object of undefined type which can be used in contexts
897where NULL (nil) is not suitable (since NULL often means 'error').
898
899Don't forget to apply Py_INCREF() when returning this value!!!
900*/
901PyAPI_DATA(PyObject) _Py_NoneStruct; /* Don't use this directly */
902#define Py_None (&_Py_NoneStruct)
903
904/* Macro for returning Py_None from a function */
905#define Py_RETURN_NONE return Py_INCREF(Py_None), Py_None
906
907/*
908Py_NotImplemented is a singleton used to signal that an operation is
909not implemented for a given type combination.
910*/
911PyAPI_DATA(PyObject) _Py_NotImplementedStruct; /* Don't use this directly */
912#define Py_NotImplemented (&_Py_NotImplementedStruct)
913
914/* Macro for returning Py_NotImplemented from a function */
915#define Py_RETURN_NOTIMPLEMENTED \
916 return Py_INCREF(Py_NotImplemented), Py_NotImplemented
917
918/* Rich comparison opcodes */
919#define Py_LT 0
920#define Py_LE 1
921#define Py_EQ 2
922#define Py_NE 3
923#define Py_GT 4
924#define Py_GE 5
925
926/* Maps Py_LT to Py_GT, ..., Py_GE to Py_LE.
927 * Defined in object.c.
928 */
929PyAPI_DATA(int) _Py_SwappedOp[];
930
931
932/*
933More conventions
934================
935
936Argument Checking
937-----------------
938
939Functions that take objects as arguments normally don't check for nil
940arguments, but they do check the type of the argument, and return an
941error if the function doesn't apply to the type.
942
943Failure Modes
944-------------
945
946Functions may fail for a variety of reasons, including running out of
947memory. This is communicated to the caller in two ways: an error string
948is set (see errors.h), and the function result differs: functions that
949normally return a pointer return NULL for failure, functions returning
950an integer return -1 (which could be a legal return value too!), and
951other functions return 0 for success and -1 for failure.
952Callers should always check for errors before using the result. If
953an error was set, the caller must either explicitly clear it, or pass
954the error on to its caller.
955
956Reference Counts
957----------------
958
959It takes a while to get used to the proper usage of reference counts.
960
961Functions that create an object set the reference count to 1; such new
962objects must be stored somewhere or destroyed again with Py_DECREF().
963Some functions that 'store' objects, such as PyTuple_SetItem() and
964PyList_SetItem(),
965don't increment the reference count of the object, since the most
966frequent use is to store a fresh object. Functions that 'retrieve'
967objects, such as PyTuple_GetItem() and PyDict_GetItemString(), also
968don't increment
969the reference count, since most frequently the object is only looked at
970quickly. Thus, to retrieve an object and store it again, the caller
971must call Py_INCREF() explicitly.
972
973NOTE: functions that 'consume' a reference count, like
974PyList_SetItem(), consume the reference even if the object wasn't
975successfully stored, to simplify error handling.
976
977It seems attractive to make other functions that take an object as
978argument consume a reference count; however, this may quickly get
979confusing (even the current practice is already confusing). Consider
980it carefully, it may save lots of calls to Py_INCREF() and Py_DECREF() at
981times.
982*/
983
984
985/* Trashcan mechanism, thanks to Christian Tismer.
986
987When deallocating a container object, it's possible to trigger an unbounded
988chain of deallocations, as each Py_DECREF in turn drops the refcount on "the
989next" object in the chain to 0. This can easily lead to stack faults, and
990especially in threads (which typically have less stack space to work with).
991
992A container object that participates in cyclic gc can avoid this by
993bracketing the body of its tp_dealloc function with a pair of macros:
994
995static void
996mytype_dealloc(mytype *p)
997{
998 ... declarations go here ...
999
1000 PyObject_GC_UnTrack(p); // must untrack first
1001 Py_TRASHCAN_SAFE_BEGIN(p)
1002 ... The body of the deallocator goes here, including all calls ...
1003 ... to Py_DECREF on contained objects. ...
1004 Py_TRASHCAN_SAFE_END(p)
1005}
1006
1007CAUTION: Never return from the middle of the body! If the body needs to
1008"get out early", put a label immediately before the Py_TRASHCAN_SAFE_END
1009call, and goto it. Else the call-depth counter (see below) will stay
1010above 0 forever, and the trashcan will never get emptied.
1011
1012How it works: The BEGIN macro increments a call-depth counter. So long
1013as this counter is small, the body of the deallocator is run directly without
1014further ado. But if the counter gets large, it instead adds p to a list of
1015objects to be deallocated later, skips the body of the deallocator, and
1016resumes execution after the END macro. The tp_dealloc routine then returns
1017without deallocating anything (and so unbounded call-stack depth is avoided).
1018
1019When the call stack finishes unwinding again, code generated by the END macro
1020notices this, and calls another routine to deallocate all the objects that
1021may have been added to the list of deferred deallocations. In effect, a
1022chain of N deallocations is broken into N / PyTrash_UNWIND_LEVEL pieces,
1023with the call stack never exceeding a depth of PyTrash_UNWIND_LEVEL.
1024*/
1025
1026/* This is the old private API, invoked by the macros before 3.2.4.
1027 Kept for binary compatibility of extensions using the stable ABI. */
1028PyAPI_FUNC(void) _PyTrash_deposit_object(PyObject*);
1029PyAPI_FUNC(void) _PyTrash_destroy_chain(void);
1030PyAPI_DATA(int) _PyTrash_delete_nesting;
1031PyAPI_DATA(PyObject *) _PyTrash_delete_later;
1032
1033/* The new thread-safe private API, invoked by the macros below. */
1034PyAPI_FUNC(void) _PyTrash_thread_deposit_object(PyObject*);
1035PyAPI_FUNC(void) _PyTrash_thread_destroy_chain(void);
1036
1037#define PyTrash_UNWIND_LEVEL 50
1038
1039#define Py_TRASHCAN_SAFE_BEGIN(op) \
1040 do { \
1041 PyThreadState *_tstate = PyThreadState_GET(); \
1042 if (_tstate->trash_delete_nesting < PyTrash_UNWIND_LEVEL) { \
1043 ++_tstate->trash_delete_nesting;
1044 /* The body of the deallocator is here. */
1045#define Py_TRASHCAN_SAFE_END(op) \
1046 --_tstate->trash_delete_nesting; \
1047 if (_tstate->trash_delete_later && _tstate->trash_delete_nesting <= 0) \
1048 _PyTrash_thread_destroy_chain(); \
1049 } \
1050 else \
1051 _PyTrash_thread_deposit_object((PyObject*)op); \
1052 } while (0);
1053
1054#ifndef Py_LIMITED_API
1055PyAPI_FUNC(void)
1056_PyDebugAllocatorStats(FILE *out, const char *block_name, int num_blocks,
1057 size_t sizeof_block);
1058PyAPI_FUNC(void)
1059_PyObject_DebugTypeStats(FILE *out);
1060#endif /* ifndef Py_LIMITED_API */
1061
1062#ifdef __cplusplus
1063}
1064#endif
1065#endif /* !Py_OBJECT_H */
1066