source: python/trunk/Include/object.h@ 390

Last change on this file since 390 was 2, checked in by Yuri Dario, 15 years ago

Initial import for vendor code.
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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#ifdef Py_TRACE_REFS
65/* Define pointers to support a doubly-linked list of all live heap objects. */
66#define _PyObject_HEAD_EXTRA \
67 struct _object *_ob_next; \
68 struct _object *_ob_prev;
69
70#define _PyObject_EXTRA_INIT 0, 0,
71
72#else
73#define _PyObject_HEAD_EXTRA
74#define _PyObject_EXTRA_INIT
75#endif
76
77/* PyObject_HEAD defines the initial segment of every PyObject. */
78#define PyObject_HEAD \
79 _PyObject_HEAD_EXTRA \
80 Py_ssize_t ob_refcnt; \
81 struct _typeobject *ob_type;
82
83#define PyObject_HEAD_INIT(type) \
84 _PyObject_EXTRA_INIT \
85 1, type,
86
87#define PyVarObject_HEAD_INIT(type, size) \
88 PyObject_HEAD_INIT(type) size,
89
90/* PyObject_VAR_HEAD defines the initial segment of all variable-size
91 * container objects. These end with a declaration of an array with 1
92 * element, but enough space is malloc'ed so that the array actually
93 * has room for ob_size elements. Note that ob_size is an element count,
94 * not necessarily a byte count.
95 */
96#define PyObject_VAR_HEAD \
97 PyObject_HEAD \
98 Py_ssize_t ob_size; /* Number of items in variable part */
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
108} PyObject;
109
110typedef struct {
111 PyObject_VAR_HEAD
112} PyVarObject;
113
114#define Py_REFCNT(ob) (((PyObject*)(ob))->ob_refcnt)
115#define Py_TYPE(ob) (((PyObject*)(ob))->ob_type)
116#define Py_SIZE(ob) (((PyVarObject*)(ob))->ob_size)
117
118/*
119Type objects contain a string containing the type name (to help somewhat
120in debugging), the allocation parameters (see PyObject_New() and
121PyObject_NewVar()),
122and methods for accessing objects of the type. Methods are optional, a
123nil pointer meaning that particular kind of access is not available for
124this type. The Py_DECREF() macro uses the tp_dealloc method without
125checking for a nil pointer; it should always be implemented except if
126the implementation can guarantee that the reference count will never
127reach zero (e.g., for statically allocated type objects).
128
129NB: the methods for certain type groups are now contained in separate
130method blocks.
131*/
132
133typedef PyObject * (*unaryfunc)(PyObject *);
134typedef PyObject * (*binaryfunc)(PyObject *, PyObject *);
135typedef PyObject * (*ternaryfunc)(PyObject *, PyObject *, PyObject *);
136typedef int (*inquiry)(PyObject *);
137typedef Py_ssize_t (*lenfunc)(PyObject *);
138typedef int (*coercion)(PyObject **, PyObject **);
139typedef PyObject *(*intargfunc)(PyObject *, int) Py_DEPRECATED(2.5);
140typedef PyObject *(*intintargfunc)(PyObject *, int, int) Py_DEPRECATED(2.5);
141typedef PyObject *(*ssizeargfunc)(PyObject *, Py_ssize_t);
142typedef PyObject *(*ssizessizeargfunc)(PyObject *, Py_ssize_t, Py_ssize_t);
143typedef int(*intobjargproc)(PyObject *, int, PyObject *);
144typedef int(*intintobjargproc)(PyObject *, int, int, PyObject *);
145typedef int(*ssizeobjargproc)(PyObject *, Py_ssize_t, PyObject *);
146typedef int(*ssizessizeobjargproc)(PyObject *, Py_ssize_t, Py_ssize_t, PyObject *);
147typedef int(*objobjargproc)(PyObject *, PyObject *, PyObject *);
148
149
150
151/* int-based buffer interface */
152typedef int (*getreadbufferproc)(PyObject *, int, void **);
153typedef int (*getwritebufferproc)(PyObject *, int, void **);
154typedef int (*getsegcountproc)(PyObject *, int *);
155typedef int (*getcharbufferproc)(PyObject *, int, char **);
156/* ssize_t-based buffer interface */
157typedef Py_ssize_t (*readbufferproc)(PyObject *, Py_ssize_t, void **);
158typedef Py_ssize_t (*writebufferproc)(PyObject *, Py_ssize_t, void **);
159typedef Py_ssize_t (*segcountproc)(PyObject *, Py_ssize_t *);
160typedef Py_ssize_t (*charbufferproc)(PyObject *, Py_ssize_t, char **);
161
162/* Py3k buffer interface */
163
164typedef struct bufferinfo {
165 void *buf;
166 PyObject *obj; /* borrowed reference */
167 Py_ssize_t len;
168 Py_ssize_t itemsize; /* This is Py_ssize_t so it can be
169 pointed to by strides in simple case.*/
170 int readonly;
171 int ndim;
172 char *format;
173 Py_ssize_t *shape;
174 Py_ssize_t *strides;
175 Py_ssize_t *suboffsets;
176 void *internal;
177} Py_buffer;
178
179typedef int (*getbufferproc)(PyObject *, Py_buffer *, int);
180typedef void (*releasebufferproc)(PyObject *, Py_buffer *);
181
182 /* Flags for getting buffers */
183#define PyBUF_SIMPLE 0
184#define PyBUF_WRITABLE 0x0001
185/* we used to include an E, backwards compatible alias */
186#define PyBUF_WRITEABLE PyBUF_WRITABLE
187#define PyBUF_FORMAT 0x0004
188#define PyBUF_ND 0x0008
189#define PyBUF_STRIDES (0x0010 | PyBUF_ND)
190#define PyBUF_C_CONTIGUOUS (0x0020 | PyBUF_STRIDES)
191#define PyBUF_F_CONTIGUOUS (0x0040 | PyBUF_STRIDES)
192#define PyBUF_ANY_CONTIGUOUS (0x0080 | PyBUF_STRIDES)
193#define PyBUF_INDIRECT (0x0100 | PyBUF_STRIDES)
194
195#define PyBUF_CONTIG (PyBUF_ND | PyBUF_WRITABLE)
196#define PyBUF_CONTIG_RO (PyBUF_ND)
197
198#define PyBUF_STRIDED (PyBUF_STRIDES | PyBUF_WRITABLE)
199#define PyBUF_STRIDED_RO (PyBUF_STRIDES)
200
201#define PyBUF_RECORDS (PyBUF_STRIDES | PyBUF_WRITABLE | PyBUF_FORMAT)
202#define PyBUF_RECORDS_RO (PyBUF_STRIDES | PyBUF_FORMAT)
203
204#define PyBUF_FULL (PyBUF_INDIRECT | PyBUF_WRITABLE | PyBUF_FORMAT)
205#define PyBUF_FULL_RO (PyBUF_INDIRECT | PyBUF_FORMAT)
206
207
208#define PyBUF_READ 0x100
209#define PyBUF_WRITE 0x200
210#define PyBUF_SHADOW 0x400
211/* end Py3k buffer interface */
212
213typedef int (*objobjproc)(PyObject *, PyObject *);
214typedef int (*visitproc)(PyObject *, void *);
215typedef int (*traverseproc)(PyObject *, visitproc, void *);
216
217typedef struct {
218 /* For numbers without flag bit Py_TPFLAGS_CHECKTYPES set, all
219 arguments are guaranteed to be of the object's type (modulo
220 coercion hacks -- i.e. if the type's coercion function
221 returns other types, then these are allowed as well). Numbers that
222 have the Py_TPFLAGS_CHECKTYPES flag bit set should check *both*
223 arguments for proper type and implement the necessary conversions
224 in the slot functions themselves. */
225
226 binaryfunc nb_add;
227 binaryfunc nb_subtract;
228 binaryfunc nb_multiply;
229 binaryfunc nb_divide;
230 binaryfunc nb_remainder;
231 binaryfunc nb_divmod;
232 ternaryfunc nb_power;
233 unaryfunc nb_negative;
234 unaryfunc nb_positive;
235 unaryfunc nb_absolute;
236 inquiry nb_nonzero;
237 unaryfunc nb_invert;
238 binaryfunc nb_lshift;
239 binaryfunc nb_rshift;
240 binaryfunc nb_and;
241 binaryfunc nb_xor;
242 binaryfunc nb_or;
243 coercion nb_coerce;
244 unaryfunc nb_int;
245 unaryfunc nb_long;
246 unaryfunc nb_float;
247 unaryfunc nb_oct;
248 unaryfunc nb_hex;
249 /* Added in release 2.0 */
250 binaryfunc nb_inplace_add;
251 binaryfunc nb_inplace_subtract;
252 binaryfunc nb_inplace_multiply;
253 binaryfunc nb_inplace_divide;
254 binaryfunc nb_inplace_remainder;
255 ternaryfunc nb_inplace_power;
256 binaryfunc nb_inplace_lshift;
257 binaryfunc nb_inplace_rshift;
258 binaryfunc nb_inplace_and;
259 binaryfunc nb_inplace_xor;
260 binaryfunc nb_inplace_or;
261
262 /* Added in release 2.2 */
263 /* The following require the Py_TPFLAGS_HAVE_CLASS flag */
264 binaryfunc nb_floor_divide;
265 binaryfunc nb_true_divide;
266 binaryfunc nb_inplace_floor_divide;
267 binaryfunc nb_inplace_true_divide;
268
269 /* Added in release 2.5 */
270 unaryfunc nb_index;
271} PyNumberMethods;
272
273typedef struct {
274 lenfunc sq_length;
275 binaryfunc sq_concat;
276 ssizeargfunc sq_repeat;
277 ssizeargfunc sq_item;
278 ssizessizeargfunc sq_slice;
279 ssizeobjargproc sq_ass_item;
280 ssizessizeobjargproc sq_ass_slice;
281 objobjproc sq_contains;
282 /* Added in release 2.0 */
283 binaryfunc sq_inplace_concat;
284 ssizeargfunc sq_inplace_repeat;
285} PySequenceMethods;
286
287typedef struct {
288 lenfunc mp_length;
289 binaryfunc mp_subscript;
290 objobjargproc mp_ass_subscript;
291} PyMappingMethods;
292
293typedef struct {
294 readbufferproc bf_getreadbuffer;
295 writebufferproc bf_getwritebuffer;
296 segcountproc bf_getsegcount;
297 charbufferproc bf_getcharbuffer;
298 getbufferproc bf_getbuffer;
299 releasebufferproc bf_releasebuffer;
300} PyBufferProcs;
301
302
303typedef void (*freefunc)(void *);
304typedef void (*destructor)(PyObject *);
305typedef int (*printfunc)(PyObject *, FILE *, int);
306typedef PyObject *(*getattrfunc)(PyObject *, char *);
307typedef PyObject *(*getattrofunc)(PyObject *, PyObject *);
308typedef int (*setattrfunc)(PyObject *, char *, PyObject *);
309typedef int (*setattrofunc)(PyObject *, PyObject *, PyObject *);
310typedef int (*cmpfunc)(PyObject *, PyObject *);
311typedef PyObject *(*reprfunc)(PyObject *);
312typedef long (*hashfunc)(PyObject *);
313typedef PyObject *(*richcmpfunc) (PyObject *, PyObject *, int);
314typedef PyObject *(*getiterfunc) (PyObject *);
315typedef PyObject *(*iternextfunc) (PyObject *);
316typedef PyObject *(*descrgetfunc) (PyObject *, PyObject *, PyObject *);
317typedef int (*descrsetfunc) (PyObject *, PyObject *, PyObject *);
318typedef int (*initproc)(PyObject *, PyObject *, PyObject *);
319typedef PyObject *(*newfunc)(struct _typeobject *, PyObject *, PyObject *);
320typedef PyObject *(*allocfunc)(struct _typeobject *, Py_ssize_t);
321
322typedef struct _typeobject {
323 PyObject_VAR_HEAD
324 const char *tp_name; /* For printing, in format "<module>.<name>" */
325 Py_ssize_t tp_basicsize, tp_itemsize; /* For allocation */
326
327 /* Methods to implement standard operations */
328
329 destructor tp_dealloc;
330 printfunc tp_print;
331 getattrfunc tp_getattr;
332 setattrfunc tp_setattr;
333 cmpfunc tp_compare;
334 reprfunc tp_repr;
335
336 /* Method suites for standard classes */
337
338 PyNumberMethods *tp_as_number;
339 PySequenceMethods *tp_as_sequence;
340 PyMappingMethods *tp_as_mapping;
341
342 /* More standard operations (here for binary compatibility) */
343
344 hashfunc tp_hash;
345 ternaryfunc tp_call;
346 reprfunc tp_str;
347 getattrofunc tp_getattro;
348 setattrofunc tp_setattro;
349
350 /* Functions to access object as input/output buffer */
351 PyBufferProcs *tp_as_buffer;
352
353 /* Flags to define presence of optional/expanded features */
354 long tp_flags;
355
356 const char *tp_doc; /* Documentation string */
357
358 /* Assigned meaning in release 2.0 */
359 /* call function for all accessible objects */
360 traverseproc tp_traverse;
361
362 /* delete references to contained objects */
363 inquiry tp_clear;
364
365 /* Assigned meaning in release 2.1 */
366 /* rich comparisons */
367 richcmpfunc tp_richcompare;
368
369 /* weak reference enabler */
370 Py_ssize_t tp_weaklistoffset;
371
372 /* Added in release 2.2 */
373 /* Iterators */
374 getiterfunc tp_iter;
375 iternextfunc tp_iternext;
376
377 /* Attribute descriptor and subclassing stuff */
378 struct PyMethodDef *tp_methods;
379 struct PyMemberDef *tp_members;
380 struct PyGetSetDef *tp_getset;
381 struct _typeobject *tp_base;
382 PyObject *tp_dict;
383 descrgetfunc tp_descr_get;
384 descrsetfunc tp_descr_set;
385 Py_ssize_t tp_dictoffset;
386 initproc tp_init;
387 allocfunc tp_alloc;
388 newfunc tp_new;
389 freefunc tp_free; /* Low-level free-memory routine */
390 inquiry tp_is_gc; /* For PyObject_IS_GC */
391 PyObject *tp_bases;
392 PyObject *tp_mro; /* method resolution order */
393 PyObject *tp_cache;
394 PyObject *tp_subclasses;
395 PyObject *tp_weaklist;
396 destructor tp_del;
397
398 /* Type attribute cache version tag. Added in version 2.6 */
399 unsigned int tp_version_tag;
400
401#ifdef COUNT_ALLOCS
402 /* these must be last and never explicitly initialized */
403 Py_ssize_t tp_allocs;
404 Py_ssize_t tp_frees;
405 Py_ssize_t tp_maxalloc;
406 struct _typeobject *tp_prev;
407 struct _typeobject *tp_next;
408#endif
409} PyTypeObject;
410
411
412/* The *real* layout of a type object when allocated on the heap */
413typedef struct _heaptypeobject {
414 /* Note: there's a dependency on the order of these members
415 in slotptr() in typeobject.c . */
416 PyTypeObject ht_type;
417 PyNumberMethods as_number;
418 PyMappingMethods as_mapping;
419 PySequenceMethods as_sequence; /* as_sequence comes after as_mapping,
420 so that the mapping wins when both
421 the mapping and the sequence define
422 a given operator (e.g. __getitem__).
423 see add_operators() in typeobject.c . */
424 PyBufferProcs as_buffer;
425 PyObject *ht_name, *ht_slots;
426 /* here are optional user slots, followed by the members. */
427} PyHeapTypeObject;
428
429/* access macro to the members which are floating "behind" the object */
430#define PyHeapType_GET_MEMBERS(etype) \
431 ((PyMemberDef *)(((char *)etype) + Py_TYPE(etype)->tp_basicsize))
432
433
434/* Generic type check */
435PyAPI_FUNC(int) PyType_IsSubtype(PyTypeObject *, PyTypeObject *);
436#define PyObject_TypeCheck(ob, tp) \
437 (Py_TYPE(ob) == (tp) || PyType_IsSubtype(Py_TYPE(ob), (tp)))
438
439PyAPI_DATA(PyTypeObject) PyType_Type; /* built-in 'type' */
440PyAPI_DATA(PyTypeObject) PyBaseObject_Type; /* built-in 'object' */
441PyAPI_DATA(PyTypeObject) PySuper_Type; /* built-in 'super' */
442
443#define PyType_Check(op) \
444 PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_TYPE_SUBCLASS)
445#define PyType_CheckExact(op) (Py_TYPE(op) == &PyType_Type)
446
447PyAPI_FUNC(int) PyType_Ready(PyTypeObject *);
448PyAPI_FUNC(PyObject *) PyType_GenericAlloc(PyTypeObject *, Py_ssize_t);
449PyAPI_FUNC(PyObject *) PyType_GenericNew(PyTypeObject *,
450 PyObject *, PyObject *);
451PyAPI_FUNC(PyObject *) _PyType_Lookup(PyTypeObject *, PyObject *);
452PyAPI_FUNC(unsigned int) PyType_ClearCache(void);
453PyAPI_FUNC(void) PyType_Modified(PyTypeObject *);
454
455/* Generic operations on objects */
456PyAPI_FUNC(int) PyObject_Print(PyObject *, FILE *, int);
457PyAPI_FUNC(void) _PyObject_Dump(PyObject *);
458PyAPI_FUNC(PyObject *) PyObject_Repr(PyObject *);
459PyAPI_FUNC(PyObject *) _PyObject_Str(PyObject *);
460PyAPI_FUNC(PyObject *) PyObject_Str(PyObject *);
461#define PyObject_Bytes PyObject_Str
462#ifdef Py_USING_UNICODE
463PyAPI_FUNC(PyObject *) PyObject_Unicode(PyObject *);
464#endif
465PyAPI_FUNC(int) PyObject_Compare(PyObject *, PyObject *);
466PyAPI_FUNC(PyObject *) PyObject_RichCompare(PyObject *, PyObject *, int);
467PyAPI_FUNC(int) PyObject_RichCompareBool(PyObject *, PyObject *, int);
468PyAPI_FUNC(PyObject *) PyObject_GetAttrString(PyObject *, const char *);
469PyAPI_FUNC(int) PyObject_SetAttrString(PyObject *, const char *, PyObject *);
470PyAPI_FUNC(int) PyObject_HasAttrString(PyObject *, const char *);
471PyAPI_FUNC(PyObject *) PyObject_GetAttr(PyObject *, PyObject *);
472PyAPI_FUNC(int) PyObject_SetAttr(PyObject *, PyObject *, PyObject *);
473PyAPI_FUNC(int) PyObject_HasAttr(PyObject *, PyObject *);
474PyAPI_FUNC(PyObject **) _PyObject_GetDictPtr(PyObject *);
475PyAPI_FUNC(PyObject *) PyObject_SelfIter(PyObject *);
476PyAPI_FUNC(PyObject *) PyObject_GenericGetAttr(PyObject *, PyObject *);
477PyAPI_FUNC(int) PyObject_GenericSetAttr(PyObject *,
478 PyObject *, PyObject *);
479PyAPI_FUNC(long) PyObject_Hash(PyObject *);
480PyAPI_FUNC(long) PyObject_HashNotImplemented(PyObject *);
481PyAPI_FUNC(int) PyObject_IsTrue(PyObject *);
482PyAPI_FUNC(int) PyObject_Not(PyObject *);
483PyAPI_FUNC(int) PyCallable_Check(PyObject *);
484PyAPI_FUNC(int) PyNumber_Coerce(PyObject **, PyObject **);
485PyAPI_FUNC(int) PyNumber_CoerceEx(PyObject **, PyObject **);
486
487PyAPI_FUNC(void) PyObject_ClearWeakRefs(PyObject *);
488
489/* A slot function whose address we need to compare */
490extern int _PyObject_SlotCompare(PyObject *, PyObject *);
491
492
493/* PyObject_Dir(obj) acts like Python __builtin__.dir(obj), returning a
494 list of strings. PyObject_Dir(NULL) is like __builtin__.dir(),
495 returning the names of the current locals. In this case, if there are
496 no current locals, NULL is returned, and PyErr_Occurred() is false.
497*/
498PyAPI_FUNC(PyObject *) PyObject_Dir(PyObject *);
499
500
501/* Helpers for printing recursive container types */
502PyAPI_FUNC(int) Py_ReprEnter(PyObject *);
503PyAPI_FUNC(void) Py_ReprLeave(PyObject *);
504
505/* Helpers for hash functions */
506PyAPI_FUNC(long) _Py_HashDouble(double);
507PyAPI_FUNC(long) _Py_HashPointer(void*);
508
509/* Helper for passing objects to printf and the like */
510#define PyObject_REPR(obj) PyString_AS_STRING(PyObject_Repr(obj))
511
512/* Flag bits for printing: */
513#define Py_PRINT_RAW 1 /* No string quotes etc. */
514
515/*
516`Type flags (tp_flags)
517
518These flags are used to extend the type structure in a backwards-compatible
519fashion. Extensions can use the flags to indicate (and test) when a given
520type structure contains a new feature. The Python core will use these when
521introducing new functionality between major revisions (to avoid mid-version
522changes in the PYTHON_API_VERSION).
523
524Arbitration of the flag bit positions will need to be coordinated among
525all extension writers who publically release their extensions (this will
526be fewer than you might expect!)..
527
528Python 1.5.2 introduced the bf_getcharbuffer slot into PyBufferProcs.
529
530Type definitions should use Py_TPFLAGS_DEFAULT for their tp_flags value.
531
532Code can use PyType_HasFeature(type_ob, flag_value) to test whether the
533given type object has a specified feature.
534
535NOTE: when building the core, Py_TPFLAGS_DEFAULT includes
536Py_TPFLAGS_HAVE_VERSION_TAG; outside the core, it doesn't. This is so
537that extensions that modify tp_dict of their own types directly don't
538break, since this was allowed in 2.5. In 3.0 they will have to
539manually remove this flag though!
540*/
541
542/* PyBufferProcs contains bf_getcharbuffer */
543#define Py_TPFLAGS_HAVE_GETCHARBUFFER (1L<<0)
544
545/* PySequenceMethods contains sq_contains */
546#define Py_TPFLAGS_HAVE_SEQUENCE_IN (1L<<1)
547
548/* This is here for backwards compatibility. Extensions that use the old GC
549 * API will still compile but the objects will not be tracked by the GC. */
550#define Py_TPFLAGS_GC 0 /* used to be (1L<<2) */
551
552/* PySequenceMethods and PyNumberMethods contain in-place operators */
553#define Py_TPFLAGS_HAVE_INPLACEOPS (1L<<3)
554
555/* PyNumberMethods do their own coercion */
556#define Py_TPFLAGS_CHECKTYPES (1L<<4)
557
558/* tp_richcompare is defined */
559#define Py_TPFLAGS_HAVE_RICHCOMPARE (1L<<5)
560
561/* Objects which are weakly referencable if their tp_weaklistoffset is >0 */
562#define Py_TPFLAGS_HAVE_WEAKREFS (1L<<6)
563
564/* tp_iter is defined */
565#define Py_TPFLAGS_HAVE_ITER (1L<<7)
566
567/* New members introduced by Python 2.2 exist */
568#define Py_TPFLAGS_HAVE_CLASS (1L<<8)
569
570/* Set if the type object is dynamically allocated */
571#define Py_TPFLAGS_HEAPTYPE (1L<<9)
572
573/* Set if the type allows subclassing */
574#define Py_TPFLAGS_BASETYPE (1L<<10)
575
576/* Set if the type is 'ready' -- fully initialized */
577#define Py_TPFLAGS_READY (1L<<12)
578
579/* Set while the type is being 'readied', to prevent recursive ready calls */
580#define Py_TPFLAGS_READYING (1L<<13)
581
582/* Objects support garbage collection (see objimp.h) */
583#define Py_TPFLAGS_HAVE_GC (1L<<14)
584
585/* These two bits are preserved for Stackless Python, next after this is 17 */
586#ifdef STACKLESS
587#define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION (3L<<15)
588#else
589#define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION 0
590#endif
591
592/* Objects support nb_index in PyNumberMethods */
593#define Py_TPFLAGS_HAVE_INDEX (1L<<17)
594
595/* Objects support type attribute cache */
596#define Py_TPFLAGS_HAVE_VERSION_TAG (1L<<18)
597#define Py_TPFLAGS_VALID_VERSION_TAG (1L<<19)
598
599/* Type is abstract and cannot be instantiated */
600#define Py_TPFLAGS_IS_ABSTRACT (1L<<20)
601
602/* Has the new buffer protocol */
603#define Py_TPFLAGS_HAVE_NEWBUFFER (1L<<21)
604
605/* These flags are used to determine if a type is a subclass. */
606#define Py_TPFLAGS_INT_SUBCLASS (1L<<23)
607#define Py_TPFLAGS_LONG_SUBCLASS (1L<<24)
608#define Py_TPFLAGS_LIST_SUBCLASS (1L<<25)
609#define Py_TPFLAGS_TUPLE_SUBCLASS (1L<<26)
610#define Py_TPFLAGS_STRING_SUBCLASS (1L<<27)
611#define Py_TPFLAGS_UNICODE_SUBCLASS (1L<<28)
612#define Py_TPFLAGS_DICT_SUBCLASS (1L<<29)
613#define Py_TPFLAGS_BASE_EXC_SUBCLASS (1L<<30)
614#define Py_TPFLAGS_TYPE_SUBCLASS (1L<<31)
615
616#define Py_TPFLAGS_DEFAULT_EXTERNAL ( \
617 Py_TPFLAGS_HAVE_GETCHARBUFFER | \
618 Py_TPFLAGS_HAVE_SEQUENCE_IN | \
619 Py_TPFLAGS_HAVE_INPLACEOPS | \
620 Py_TPFLAGS_HAVE_RICHCOMPARE | \
621 Py_TPFLAGS_HAVE_WEAKREFS | \
622 Py_TPFLAGS_HAVE_ITER | \
623 Py_TPFLAGS_HAVE_CLASS | \
624 Py_TPFLAGS_HAVE_STACKLESS_EXTENSION | \
625 Py_TPFLAGS_HAVE_INDEX | \
626 0)
627#define Py_TPFLAGS_DEFAULT_CORE (Py_TPFLAGS_DEFAULT_EXTERNAL | \
628 Py_TPFLAGS_HAVE_VERSION_TAG)
629
630#ifdef Py_BUILD_CORE
631#define Py_TPFLAGS_DEFAULT Py_TPFLAGS_DEFAULT_CORE
632#else
633#define Py_TPFLAGS_DEFAULT Py_TPFLAGS_DEFAULT_EXTERNAL
634#endif
635
636#define PyType_HasFeature(t,f) (((t)->tp_flags & (f)) != 0)
637#define PyType_FastSubclass(t,f) PyType_HasFeature(t,f)
638
639
640/*
641The macros Py_INCREF(op) and Py_DECREF(op) are used to increment or decrement
642reference counts. Py_DECREF calls the object's deallocator function when
643the refcount falls to 0; for
644objects that don't contain references to other objects or heap memory
645this can be the standard function free(). Both macros can be used
646wherever a void expression is allowed. The argument must not be a
647NULL pointer. If it may be NULL, use Py_XINCREF/Py_XDECREF instead.
648The macro _Py_NewReference(op) initialize reference counts to 1, and
649in special builds (Py_REF_DEBUG, Py_TRACE_REFS) performs additional
650bookkeeping appropriate to the special build.
651
652We assume that the reference count field can never overflow; this can
653be proven when the size of the field is the same as the pointer size, so
654we ignore the possibility. Provided a C int is at least 32 bits (which
655is implicitly assumed in many parts of this code), that's enough for
656about 2**31 references to an object.
657
658XXX The following became out of date in Python 2.2, but I'm not sure
659XXX what the full truth is now. Certainly, heap-allocated type objects
660XXX can and should be deallocated.
661Type objects should never be deallocated; the type pointer in an object
662is not considered to be a reference to the type object, to save
663complications in the deallocation function. (This is actually a
664decision that's up to the implementer of each new type so if you want,
665you can count such references to the type object.)
666
667*** WARNING*** The Py_DECREF macro must have a side-effect-free argument
668since it may evaluate its argument multiple times. (The alternative
669would be to mace it a proper function or assign it to a global temporary
670variable first, both of which are slower; and in a multi-threaded
671environment the global variable trick is not safe.)
672*/
673
674/* First define a pile of simple helper macros, one set per special
675 * build symbol. These either expand to the obvious things, or to
676 * nothing at all when the special mode isn't in effect. The main
677 * macros can later be defined just once then, yet expand to different
678 * things depending on which special build options are and aren't in effect.
679 * Trust me <wink>: while painful, this is 20x easier to understand than,
680 * e.g, defining _Py_NewReference five different times in a maze of nested
681 * #ifdefs (we used to do that -- it was impenetrable).
682 */
683#ifdef Py_REF_DEBUG
684PyAPI_DATA(Py_ssize_t) _Py_RefTotal;
685PyAPI_FUNC(void) _Py_NegativeRefcount(const char *fname,
686 int lineno, PyObject *op);
687PyAPI_FUNC(PyObject *) _PyDict_Dummy(void);
688PyAPI_FUNC(PyObject *) _PySet_Dummy(void);
689PyAPI_FUNC(Py_ssize_t) _Py_GetRefTotal(void);
690#define _Py_INC_REFTOTAL _Py_RefTotal++
691#define _Py_DEC_REFTOTAL _Py_RefTotal--
692#define _Py_REF_DEBUG_COMMA ,
693#define _Py_CHECK_REFCNT(OP) \
694{ if (((PyObject*)OP)->ob_refcnt < 0) \
695 _Py_NegativeRefcount(__FILE__, __LINE__, \
696 (PyObject *)(OP)); \
697}
698#else
699#define _Py_INC_REFTOTAL
700#define _Py_DEC_REFTOTAL
701#define _Py_REF_DEBUG_COMMA
702#define _Py_CHECK_REFCNT(OP) /* a semicolon */;
703#endif /* Py_REF_DEBUG */
704
705#ifdef COUNT_ALLOCS
706PyAPI_FUNC(void) inc_count(PyTypeObject *);
707PyAPI_FUNC(void) dec_count(PyTypeObject *);
708#define _Py_INC_TPALLOCS(OP) inc_count(Py_TYPE(OP))
709#define _Py_INC_TPFREES(OP) dec_count(Py_TYPE(OP))
710#define _Py_DEC_TPFREES(OP) Py_TYPE(OP)->tp_frees--
711#define _Py_COUNT_ALLOCS_COMMA ,
712#else
713#define _Py_INC_TPALLOCS(OP)
714#define _Py_INC_TPFREES(OP)
715#define _Py_DEC_TPFREES(OP)
716#define _Py_COUNT_ALLOCS_COMMA
717#endif /* COUNT_ALLOCS */
718
719#ifdef Py_TRACE_REFS
720/* Py_TRACE_REFS is such major surgery that we call external routines. */
721PyAPI_FUNC(void) _Py_NewReference(PyObject *);
722PyAPI_FUNC(void) _Py_ForgetReference(PyObject *);
723PyAPI_FUNC(void) _Py_Dealloc(PyObject *);
724PyAPI_FUNC(void) _Py_PrintReferences(FILE *);
725PyAPI_FUNC(void) _Py_PrintReferenceAddresses(FILE *);
726PyAPI_FUNC(void) _Py_AddToAllObjects(PyObject *, int force);
727
728#else
729/* Without Py_TRACE_REFS, there's little enough to do that we expand code
730 * inline.
731 */
732#define _Py_NewReference(op) ( \
733 _Py_INC_TPALLOCS(op) _Py_COUNT_ALLOCS_COMMA \
734 _Py_INC_REFTOTAL _Py_REF_DEBUG_COMMA \
735 Py_REFCNT(op) = 1)
736
737#define _Py_ForgetReference(op) _Py_INC_TPFREES(op)
738
739#define _Py_Dealloc(op) ( \
740 _Py_INC_TPFREES(op) _Py_COUNT_ALLOCS_COMMA \
741 (*Py_TYPE(op)->tp_dealloc)((PyObject *)(op)))
742#endif /* !Py_TRACE_REFS */
743
744#define Py_INCREF(op) ( \
745 _Py_INC_REFTOTAL _Py_REF_DEBUG_COMMA \
746 ((PyObject*)(op))->ob_refcnt++)
747
748#define Py_DECREF(op) \
749 if (_Py_DEC_REFTOTAL _Py_REF_DEBUG_COMMA \
750 --((PyObject*)(op))->ob_refcnt != 0) \
751 _Py_CHECK_REFCNT(op) \
752 else \
753 _Py_Dealloc((PyObject *)(op))
754
755/* Safely decref `op` and set `op` to NULL, especially useful in tp_clear
756 * and tp_dealloc implementatons.
757 *
758 * Note that "the obvious" code can be deadly:
759 *
760 * Py_XDECREF(op);
761 * op = NULL;
762 *
763 * Typically, `op` is something like self->containee, and `self` is done
764 * using its `containee` member. In the code sequence above, suppose
765 * `containee` is non-NULL with a refcount of 1. Its refcount falls to
766 * 0 on the first line, which can trigger an arbitrary amount of code,
767 * possibly including finalizers (like __del__ methods or weakref callbacks)
768 * coded in Python, which in turn can release the GIL and allow other threads
769 * to run, etc. Such code may even invoke methods of `self` again, or cause
770 * cyclic gc to trigger, but-- oops! --self->containee still points to the
771 * object being torn down, and it may be in an insane state while being torn
772 * down. This has in fact been a rich historic source of miserable (rare &
773 * hard-to-diagnose) segfaulting (and other) bugs.
774 *
775 * The safe way is:
776 *
777 * Py_CLEAR(op);
778 *
779 * That arranges to set `op` to NULL _before_ decref'ing, so that any code
780 * triggered as a side-effect of `op` getting torn down no longer believes
781 * `op` points to a valid object.
782 *
783 * There are cases where it's safe to use the naive code, but they're brittle.
784 * For example, if `op` points to a Python integer, you know that destroying
785 * one of those can't cause problems -- but in part that relies on that
786 * Python integers aren't currently weakly referencable. Best practice is
787 * to use Py_CLEAR() even if you can't think of a reason for why you need to.
788 */
789#define Py_CLEAR(op) \
790 do { \
791 if (op) { \
792 PyObject *_py_tmp = (PyObject *)(op); \
793 (op) = NULL; \
794 Py_DECREF(_py_tmp); \
795 } \
796 } while (0)
797
798/* Macros to use in case the object pointer may be NULL: */
799#define Py_XINCREF(op) if ((op) == NULL) ; else Py_INCREF(op)
800#define Py_XDECREF(op) if ((op) == NULL) ; else Py_DECREF(op)
801
802/*
803These are provided as conveniences to Python runtime embedders, so that
804they can have object code that is not dependent on Python compilation flags.
805*/
806PyAPI_FUNC(void) Py_IncRef(PyObject *);
807PyAPI_FUNC(void) Py_DecRef(PyObject *);
808
809/*
810_Py_NoneStruct is an object of undefined type which can be used in contexts
811where NULL (nil) is not suitable (since NULL often means 'error').
812
813Don't forget to apply Py_INCREF() when returning this value!!!
814*/
815PyAPI_DATA(PyObject) _Py_NoneStruct; /* Don't use this directly */
816#define Py_None (&_Py_NoneStruct)
817
818/* Macro for returning Py_None from a function */
819#define Py_RETURN_NONE return Py_INCREF(Py_None), Py_None
820
821/*
822Py_NotImplemented is a singleton used to signal that an operation is
823not implemented for a given type combination.
824*/
825PyAPI_DATA(PyObject) _Py_NotImplementedStruct; /* Don't use this directly */
826#define Py_NotImplemented (&_Py_NotImplementedStruct)
827
828/* Rich comparison opcodes */
829#define Py_LT 0
830#define Py_LE 1
831#define Py_EQ 2
832#define Py_NE 3
833#define Py_GT 4
834#define Py_GE 5
835
836/* Maps Py_LT to Py_GT, ..., Py_GE to Py_LE.
837 * Defined in object.c.
838 */
839PyAPI_DATA(int) _Py_SwappedOp[];
840
841/*
842Define staticforward and statichere for source compatibility with old
843C extensions.
844
845The staticforward define was needed to support certain broken C
846compilers (notably SCO ODT 3.0, perhaps early AIX as well) botched the
847static keyword when it was used with a forward declaration of a static
848initialized structure. Standard C allows the forward declaration with
849static, and we've decided to stop catering to broken C compilers.
850(In fact, we expect that the compilers are all fixed eight years later.)
851*/
852
853#define staticforward static
854#define statichere static
855
856
857/*
858More conventions
859================
860
861Argument Checking
862-----------------
863
864Functions that take objects as arguments normally don't check for nil
865arguments, but they do check the type of the argument, and return an
866error if the function doesn't apply to the type.
867
868Failure Modes
869-------------
870
871Functions may fail for a variety of reasons, including running out of
872memory. This is communicated to the caller in two ways: an error string
873is set (see errors.h), and the function result differs: functions that
874normally return a pointer return NULL for failure, functions returning
875an integer return -1 (which could be a legal return value too!), and
876other functions return 0 for success and -1 for failure.
877Callers should always check for errors before using the result. If
878an error was set, the caller must either explicitly clear it, or pass
879the error on to its caller.
880
881Reference Counts
882----------------
883
884It takes a while to get used to the proper usage of reference counts.
885
886Functions that create an object set the reference count to 1; such new
887objects must be stored somewhere or destroyed again with Py_DECREF().
888Some functions that 'store' objects, such as PyTuple_SetItem() and
889PyList_SetItem(),
890don't increment the reference count of the object, since the most
891frequent use is to store a fresh object. Functions that 'retrieve'
892objects, such as PyTuple_GetItem() and PyDict_GetItemString(), also
893don't increment
894the reference count, since most frequently the object is only looked at
895quickly. Thus, to retrieve an object and store it again, the caller
896must call Py_INCREF() explicitly.
897
898NOTE: functions that 'consume' a reference count, like
899PyList_SetItem(), consume the reference even if the object wasn't
900successfully stored, to simplify error handling.
901
902It seems attractive to make other functions that take an object as
903argument consume a reference count; however, this may quickly get
904confusing (even the current practice is already confusing). Consider
905it carefully, it may save lots of calls to Py_INCREF() and Py_DECREF() at
906times.
907*/
908
909
910/* Trashcan mechanism, thanks to Christian Tismer.
911
912When deallocating a container object, it's possible to trigger an unbounded
913chain of deallocations, as each Py_DECREF in turn drops the refcount on "the
914next" object in the chain to 0. This can easily lead to stack faults, and
915especially in threads (which typically have less stack space to work with).
916
917A container object that participates in cyclic gc can avoid this by
918bracketing the body of its tp_dealloc function with a pair of macros:
919
920static void
921mytype_dealloc(mytype *p)
922{
923 ... declarations go here ...
924
925 PyObject_GC_UnTrack(p); // must untrack first
926 Py_TRASHCAN_SAFE_BEGIN(p)
927 ... The body of the deallocator goes here, including all calls ...
928 ... to Py_DECREF on contained objects. ...
929 Py_TRASHCAN_SAFE_END(p)
930}
931
932CAUTION: Never return from the middle of the body! If the body needs to
933"get out early", put a label immediately before the Py_TRASHCAN_SAFE_END
934call, and goto it. Else the call-depth counter (see below) will stay
935above 0 forever, and the trashcan will never get emptied.
936
937How it works: The BEGIN macro increments a call-depth counter. So long
938as this counter is small, the body of the deallocator is run directly without
939further ado. But if the counter gets large, it instead adds p to a list of
940objects to be deallocated later, skips the body of the deallocator, and
941resumes execution after the END macro. The tp_dealloc routine then returns
942without deallocating anything (and so unbounded call-stack depth is avoided).
943
944When the call stack finishes unwinding again, code generated by the END macro
945notices this, and calls another routine to deallocate all the objects that
946may have been added to the list of deferred deallocations. In effect, a
947chain of N deallocations is broken into N / PyTrash_UNWIND_LEVEL pieces,
948with the call stack never exceeding a depth of PyTrash_UNWIND_LEVEL.
949*/
950
951PyAPI_FUNC(void) _PyTrash_deposit_object(PyObject*);
952PyAPI_FUNC(void) _PyTrash_destroy_chain(void);
953PyAPI_DATA(int) _PyTrash_delete_nesting;
954PyAPI_DATA(PyObject *) _PyTrash_delete_later;
955
956#define PyTrash_UNWIND_LEVEL 50
957
958#define Py_TRASHCAN_SAFE_BEGIN(op) \
959 if (_PyTrash_delete_nesting < PyTrash_UNWIND_LEVEL) { \
960 ++_PyTrash_delete_nesting;
961 /* The body of the deallocator is here. */
962#define Py_TRASHCAN_SAFE_END(op) \
963 --_PyTrash_delete_nesting; \
964 if (_PyTrash_delete_later && _PyTrash_delete_nesting <= 0) \
965 _PyTrash_destroy_chain(); \
966 } \
967 else \
968 _PyTrash_deposit_object((PyObject*)op);
969
970#ifdef __cplusplus
971}
972#endif
973#endif /* !Py_OBJECT_H */
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