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The C and C++ Include Header Files
/usr/include/python3.12/object.h
$ cat -n /usr/include/python3.12/object.h 1 #ifndef Py_OBJECT_H 2 #define Py_OBJECT_H 3 #ifdef __cplusplus 4 extern "C" { 5 #endif 6 7 8 /* Object and type object interface */ 9 10 /* 11 Objects are structures allocated on the heap. Special rules apply to 12 the use of objects to ensure they are properly garbage-collected. 13 Objects are never allocated statically or on the stack; they must be 14 accessed through special macros and functions only. (Type objects are 15 exceptions to the first rule; the standard types are represented by 16 statically initialized type objects, although work on type/class unification 17 for Python 2.2 made it possible to have heap-allocated type objects too). 18 19 An object has a 'reference count' that is increased or decreased when a 20 pointer to the object is copied or deleted; when the reference count 21 reaches zero there are no references to the object left and it can be 22 removed from the heap. 23 24 An object has a 'type' that determines what it represents and what kind 25 of data it contains. An object's type is fixed when it is created. 26 Types themselves are represented as objects; an object contains a 27 pointer to the corresponding type object. The type itself has a type 28 pointer pointing to the object representing the type 'type', which 29 contains a pointer to itself!. 30 31 Objects do not float around in memory; once allocated an object keeps 32 the same size and address. Objects that must hold variable-size data 33 can contain pointers to variable-size parts of the object. Not all 34 objects of the same type have the same size; but the size cannot change 35 after allocation. (These restrictions are made so a reference to an 36 object can be simply a pointer -- moving an object would require 37 updating all the pointers, and changing an object's size would require 38 moving it if there was another object right next to it.) 39 40 Objects are always accessed through pointers of the type 'PyObject *'. 41 The type 'PyObject' is a structure that only contains the reference count 42 and the type pointer. The actual memory allocated for an object 43 contains other data that can only be accessed after casting the pointer 44 to a pointer to a longer structure type. This longer type must start 45 with the reference count and type fields; the macro PyObject_HEAD should be 46 used for this (to accommodate for future changes). The implementation 47 of a particular object type can cast the object pointer to the proper 48 type and back. 49 50 A standard interface exists for objects that contain an array of items 51 whose size is determined when the object is allocated. 52 */ 53 54 #include "pystats.h" 55 56 /* Py_DEBUG implies Py_REF_DEBUG. */ 57 #if defined(Py_DEBUG) && !defined(Py_REF_DEBUG) 58 # define Py_REF_DEBUG 59 #endif 60 61 #if defined(Py_LIMITED_API) && defined(Py_TRACE_REFS) 62 # error Py_LIMITED_API is incompatible with Py_TRACE_REFS 63 #endif 64 65 #ifdef Py_TRACE_REFS 66 /* Define pointers to support a doubly-linked list of all live heap objects. */ 67 #define _PyObject_HEAD_EXTRA \ 68 PyObject *_ob_next; \ 69 PyObject *_ob_prev; 70 71 #define _PyObject_EXTRA_INIT _Py_NULL, _Py_NULL, 72 73 #else 74 # define _PyObject_HEAD_EXTRA 75 # define _PyObject_EXTRA_INIT 76 #endif 77 78 /* PyObject_HEAD defines the initial segment of every PyObject. */ 79 #define PyObject_HEAD PyObject ob_base; 80 81 /* 82 Immortalization: 83 84 The following indicates the immortalization strategy depending on the amount 85 of available bits in the reference count field. All strategies are backwards 86 compatible but the specific reference count value or immortalization check 87 might change depending on the specializations for the underlying system. 88 89 Proper deallocation of immortal instances requires distinguishing between 90 statically allocated immortal instances vs those promoted by the runtime to be 91 immortal. The latter should be the only instances that require 92 cleanup during runtime finalization. 93 */ 94 95 #if SIZEOF_VOID_P > 4 96 /* 97 In 64+ bit systems, an object will be marked as immortal by setting all of the 98 lower 32 bits of the reference count field, which is equal to: 0xFFFFFFFF 99 100 Using the lower 32 bits makes the value backwards compatible by allowing 101 C-Extensions without the updated checks in Py_INCREF and Py_DECREF to safely 102 increase and decrease the objects reference count. The object would lose its 103 immortality, but the execution would still be correct. 104 105 Reference count increases will use saturated arithmetic, taking advantage of 106 having all the lower 32 bits set, which will avoid the reference count to go 107 beyond the refcount limit. Immortality checks for reference count decreases will 108 be done by checking the bit sign flag in the lower 32 bits. 109 */ 110 #define _Py_IMMORTAL_REFCNT UINT_MAX 111 112 #else 113 /* 114 In 32 bit systems, an object will be marked as immortal by setting all of the 115 lower 30 bits of the reference count field, which is equal to: 0x3FFFFFFF 116 117 Using the lower 30 bits makes the value backwards compatible by allowing 118 C-Extensions without the updated checks in Py_INCREF and Py_DECREF to safely 119 increase and decrease the objects reference count. The object would lose its 120 immortality, but the execution would still be correct. 121 122 Reference count increases and decreases will first go through an immortality 123 check by comparing the reference count field to the immortality reference count. 124 */ 125 #define _Py_IMMORTAL_REFCNT (UINT_MAX >> 2) 126 #endif 127 128 // Make all internal uses of PyObject_HEAD_INIT immortal while preserving the 129 // C-API expectation that the refcnt will be set to 1. 130 #ifdef Py_BUILD_CORE 131 #define PyObject_HEAD_INIT(type) \ 132 { \ 133 _PyObject_EXTRA_INIT \ 134 { _Py_IMMORTAL_REFCNT }, \ 135 (type) \ 136 }, 137 #else 138 #define PyObject_HEAD_INIT(type) \ 139 { \ 140 _PyObject_EXTRA_INIT \ 141 { 1 }, \ 142 (type) \ 143 }, 144 #endif /* Py_BUILD_CORE */ 145 146 #define PyVarObject_HEAD_INIT(type, size) \ 147 { \ 148 PyObject_HEAD_INIT(type) \ 149 (size) \ 150 }, 151 152 /* PyObject_VAR_HEAD defines the initial segment of all variable-size 153 * container objects. These end with a declaration of an array with 1 154 * element, but enough space is malloc'ed so that the array actually 155 * has room for ob_size elements. Note that ob_size is an element count, 156 * not necessarily a byte count. 157 */ 158 #define PyObject_VAR_HEAD PyVarObject ob_base; 159 #define Py_INVALID_SIZE (Py_ssize_t)-1 160 161 /* Nothing is actually declared to be a PyObject, but every pointer to 162 * a Python object can be cast to a PyObject*. This is inheritance built 163 * by hand. Similarly every pointer to a variable-size Python object can, 164 * in addition, be cast to PyVarObject*. 165 */ 166 struct _object { 167 _PyObject_HEAD_EXTRA 168 169 #if (defined(__GNUC__) || defined(__clang__)) \ 170 && !(defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L) 171 // On C99 and older, anonymous union is a GCC and clang extension 172 __extension__ 173 #endif 174 #ifdef _MSC_VER 175 // Ignore MSC warning C4201: "nonstandard extension used: 176 // nameless struct/union" 177 __pragma(warning(push)) 178 __pragma(warning(disable: 4201)) 179 #endif 180 union { 181 Py_ssize_t ob_refcnt; 182 #if SIZEOF_VOID_P > 4 183 PY_UINT32_T ob_refcnt_split[2]; 184 #endif 185 }; 186 #ifdef _MSC_VER 187 __pragma(warning(pop)) 188 #endif 189 190 PyTypeObject *ob_type; 191 }; 192 193 /* Cast argument to PyObject* type. */ 194 #define _PyObject_CAST(op) _Py_CAST(PyObject*, (op)) 195 196 typedef struct { 197 PyObject ob_base; 198 Py_ssize_t ob_size; /* Number of items in variable part */ 199 } PyVarObject; 200 201 /* Cast argument to PyVarObject* type. */ 202 #define _PyVarObject_CAST(op) _Py_CAST(PyVarObject*, (op)) 203 204 205 // Test if the 'x' object is the 'y' object, the same as "x is y" in Python. 206 PyAPI_FUNC(int) Py_Is(PyObject *x, PyObject *y); 207 #define Py_Is(x, y) ((x) == (y)) 208 209 210 static inline Py_ssize_t Py_REFCNT(PyObject *ob) { 211 return ob->ob_refcnt; 212 } 213 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000 214 # define Py_REFCNT(ob) Py_REFCNT(_PyObject_CAST(ob)) 215 #endif 216 217 218 // bpo-39573: The Py_SET_TYPE() function must be used to set an object type. 219 static inline PyTypeObject* Py_TYPE(PyObject *ob) { 220 return ob->ob_type; 221 } 222 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000 223 # define Py_TYPE(ob) Py_TYPE(_PyObject_CAST(ob)) 224 #endif 225 226 PyAPI_DATA(PyTypeObject) PyLong_Type; 227 PyAPI_DATA(PyTypeObject) PyBool_Type; 228 229 // bpo-39573: The Py_SET_SIZE() function must be used to set an object size. 230 static inline Py_ssize_t Py_SIZE(PyObject *ob) { 231 assert(ob->ob_type != &PyLong_Type); 232 assert(ob->ob_type != &PyBool_Type); 233 return _PyVarObject_CAST(ob)->ob_size; 234 } 235 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000 236 # define Py_SIZE(ob) Py_SIZE(_PyObject_CAST(ob)) 237 #endif 238 239 static inline Py_ALWAYS_INLINE int _Py_IsImmortal(PyObject *op) 240 { 241 #if SIZEOF_VOID_P > 4 242 return _Py_CAST(PY_INT32_T, op->ob_refcnt) < 0; 243 #else 244 return op->ob_refcnt == _Py_IMMORTAL_REFCNT; 245 #endif 246 } 247 #define _Py_IsImmortal(op) _Py_IsImmortal(_PyObject_CAST(op)) 248 249 static inline int Py_IS_TYPE(PyObject *ob, PyTypeObject *type) { 250 return Py_TYPE(ob) == type; 251 } 252 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000 253 # define Py_IS_TYPE(ob, type) Py_IS_TYPE(_PyObject_CAST(ob), (type)) 254 #endif 255 256 257 static inline void Py_SET_REFCNT(PyObject *ob, Py_ssize_t refcnt) { 258 // This immortal check is for code that is unaware of immortal objects. 259 // The runtime tracks these objects and we should avoid as much 260 // as possible having extensions inadvertently change the refcnt 261 // of an immortalized object. 262 if (_Py_IsImmortal(ob)) { 263 return; 264 } 265 ob->ob_refcnt = refcnt; 266 } 267 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000 268 # define Py_SET_REFCNT(ob, refcnt) Py_SET_REFCNT(_PyObject_CAST(ob), (refcnt)) 269 #endif 270 271 272 static inline void Py_SET_TYPE(PyObject *ob, PyTypeObject *type) { 273 ob->ob_type = type; 274 } 275 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000 276 # define Py_SET_TYPE(ob, type) Py_SET_TYPE(_PyObject_CAST(ob), type) 277 #endif 278 279 static inline void Py_SET_SIZE(PyVarObject *ob, Py_ssize_t size) { 280 assert(ob->ob_base.ob_type != &PyLong_Type); 281 assert(ob->ob_base.ob_type != &PyBool_Type); 282 ob->ob_size = size; 283 } 284 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000 285 # define Py_SET_SIZE(ob, size) Py_SET_SIZE(_PyVarObject_CAST(ob), (size)) 286 #endif 287 288 289 /* 290 Type objects contain a string containing the type name (to help somewhat 291 in debugging), the allocation parameters (see PyObject_New() and 292 PyObject_NewVar()), 293 and methods for accessing objects of the type. Methods are optional, a 294 nil pointer meaning that particular kind of access is not available for 295 this type. The Py_DECREF() macro uses the tp_dealloc method without 296 checking for a nil pointer; it should always be implemented except if 297 the implementation can guarantee that the reference count will never 298 reach zero (e.g., for statically allocated type objects). 299 300 NB: the methods for certain type groups are now contained in separate 301 method blocks. 302 */ 303 304 typedef PyObject * (*unaryfunc)(PyObject *); 305 typedef PyObject * (*binaryfunc)(PyObject *, PyObject *); 306 typedef PyObject * (*ternaryfunc)(PyObject *, PyObject *, PyObject *); 307 typedef int (*inquiry)(PyObject *); 308 typedef Py_ssize_t (*lenfunc)(PyObject *); 309 typedef PyObject *(*ssizeargfunc)(PyObject *, Py_ssize_t); 310 typedef PyObject *(*ssizessizeargfunc)(PyObject *, Py_ssize_t, Py_ssize_t); 311 typedef int(*ssizeobjargproc)(PyObject *, Py_ssize_t, PyObject *); 312 typedef int(*ssizessizeobjargproc)(PyObject *, Py_ssize_t, Py_ssize_t, PyObject *); 313 typedef int(*objobjargproc)(PyObject *, PyObject *, PyObject *); 314 315 typedef int (*objobjproc)(PyObject *, PyObject *); 316 typedef int (*visitproc)(PyObject *, void *); 317 typedef int (*traverseproc)(PyObject *, visitproc, void *); 318 319 320 typedef void (*freefunc)(void *); 321 typedef void (*destructor)(PyObject *); 322 typedef PyObject *(*getattrfunc)(PyObject *, char *); 323 typedef PyObject *(*getattrofunc)(PyObject *, PyObject *); 324 typedef int (*setattrfunc)(PyObject *, char *, PyObject *); 325 typedef int (*setattrofunc)(PyObject *, PyObject *, PyObject *); 326 typedef PyObject *(*reprfunc)(PyObject *); 327 typedef Py_hash_t (*hashfunc)(PyObject *); 328 typedef PyObject *(*richcmpfunc) (PyObject *, PyObject *, int); 329 typedef PyObject *(*getiterfunc) (PyObject *); 330 typedef PyObject *(*iternextfunc) (PyObject *); 331 typedef PyObject *(*descrgetfunc) (PyObject *, PyObject *, PyObject *); 332 typedef int (*descrsetfunc) (PyObject *, PyObject *, PyObject *); 333 typedef int (*initproc)(PyObject *, PyObject *, PyObject *); 334 typedef PyObject *(*newfunc)(PyTypeObject *, PyObject *, PyObject *); 335 typedef PyObject *(*allocfunc)(PyTypeObject *, Py_ssize_t); 336 337 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030c0000 // 3.12 338 typedef PyObject *(*vectorcallfunc)(PyObject *callable, PyObject *const *args, 339 size_t nargsf, PyObject *kwnames); 340 #endif 341 342 typedef struct{ 343 int slot; /* slot id, see below */ 344 void *pfunc; /* function pointer */ 345 } PyType_Slot; 346 347 typedef struct{ 348 const char* name; 349 int basicsize; 350 int itemsize; 351 unsigned int flags; 352 PyType_Slot *slots; /* terminated by slot==0. */ 353 } PyType_Spec; 354 355 PyAPI_FUNC(PyObject*) PyType_FromSpec(PyType_Spec*); 356 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03030000 357 PyAPI_FUNC(PyObject*) PyType_FromSpecWithBases(PyType_Spec*, PyObject*); 358 #endif 359 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03040000 360 PyAPI_FUNC(void*) PyType_GetSlot(PyTypeObject*, int); 361 #endif 362 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03090000 363 PyAPI_FUNC(PyObject*) PyType_FromModuleAndSpec(PyObject *, PyType_Spec *, PyObject *); 364 PyAPI_FUNC(PyObject *) PyType_GetModule(PyTypeObject *); 365 PyAPI_FUNC(void *) PyType_GetModuleState(PyTypeObject *); 366 #endif 367 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030B0000 368 PyAPI_FUNC(PyObject *) PyType_GetName(PyTypeObject *); 369 PyAPI_FUNC(PyObject *) PyType_GetQualName(PyTypeObject *); 370 #endif 371 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030C0000 372 PyAPI_FUNC(PyObject *) PyType_FromMetaclass(PyTypeObject*, PyObject*, PyType_Spec*, PyObject*); 373 PyAPI_FUNC(void *) PyObject_GetTypeData(PyObject *obj, PyTypeObject *cls); 374 PyAPI_FUNC(Py_ssize_t) PyType_GetTypeDataSize(PyTypeObject *cls); 375 #endif 376 377 /* Generic type check */ 378 PyAPI_FUNC(int) PyType_IsSubtype(PyTypeObject *, PyTypeObject *); 379 380 static inline int PyObject_TypeCheck(PyObject *ob, PyTypeObject *type) { 381 return Py_IS_TYPE(ob, type) || PyType_IsSubtype(Py_TYPE(ob), type); 382 } 383 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000 384 # define PyObject_TypeCheck(ob, type) PyObject_TypeCheck(_PyObject_CAST(ob), (type)) 385 #endif 386 387 PyAPI_DATA(PyTypeObject) PyType_Type; /* built-in 'type' */ 388 PyAPI_DATA(PyTypeObject) PyBaseObject_Type; /* built-in 'object' */ 389 PyAPI_DATA(PyTypeObject) PySuper_Type; /* built-in 'super' */ 390 391 PyAPI_FUNC(unsigned long) PyType_GetFlags(PyTypeObject*); 392 393 PyAPI_FUNC(int) PyType_Ready(PyTypeObject *); 394 PyAPI_FUNC(PyObject *) PyType_GenericAlloc(PyTypeObject *, Py_ssize_t); 395 PyAPI_FUNC(PyObject *) PyType_GenericNew(PyTypeObject *, 396 PyObject *, PyObject *); 397 PyAPI_FUNC(unsigned int) PyType_ClearCache(void); 398 PyAPI_FUNC(void) PyType_Modified(PyTypeObject *); 399 400 /* Generic operations on objects */ 401 PyAPI_FUNC(PyObject *) PyObject_Repr(PyObject *); 402 PyAPI_FUNC(PyObject *) PyObject_Str(PyObject *); 403 PyAPI_FUNC(PyObject *) PyObject_ASCII(PyObject *); 404 PyAPI_FUNC(PyObject *) PyObject_Bytes(PyObject *); 405 PyAPI_FUNC(PyObject *) PyObject_RichCompare(PyObject *, PyObject *, int); 406 PyAPI_FUNC(int) PyObject_RichCompareBool(PyObject *, PyObject *, int); 407 PyAPI_FUNC(PyObject *) PyObject_GetAttrString(PyObject *, const char *); 408 PyAPI_FUNC(int) PyObject_SetAttrString(PyObject *, const char *, PyObject *); 409 PyAPI_FUNC(int) PyObject_HasAttrString(PyObject *, const char *); 410 PyAPI_FUNC(PyObject *) PyObject_GetAttr(PyObject *, PyObject *); 411 PyAPI_FUNC(int) PyObject_SetAttr(PyObject *, PyObject *, PyObject *); 412 PyAPI_FUNC(int) PyObject_HasAttr(PyObject *, PyObject *); 413 PyAPI_FUNC(PyObject *) PyObject_SelfIter(PyObject *); 414 PyAPI_FUNC(PyObject *) PyObject_GenericGetAttr(PyObject *, PyObject *); 415 PyAPI_FUNC(int) PyObject_GenericSetAttr(PyObject *, PyObject *, PyObject *); 416 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03030000 417 PyAPI_FUNC(int) PyObject_GenericSetDict(PyObject *, PyObject *, void *); 418 #endif 419 PyAPI_FUNC(Py_hash_t) PyObject_Hash(PyObject *); 420 PyAPI_FUNC(Py_hash_t) PyObject_HashNotImplemented(PyObject *); 421 PyAPI_FUNC(int) PyObject_IsTrue(PyObject *); 422 PyAPI_FUNC(int) PyObject_Not(PyObject *); 423 PyAPI_FUNC(int) PyCallable_Check(PyObject *); 424 PyAPI_FUNC(void) PyObject_ClearWeakRefs(PyObject *); 425 426 /* PyObject_Dir(obj) acts like Python builtins.dir(obj), returning a 427 list of strings. PyObject_Dir(NULL) is like builtins.dir(), 428 returning the names of the current locals. In this case, if there are 429 no current locals, NULL is returned, and PyErr_Occurred() is false. 430 */ 431 PyAPI_FUNC(PyObject *) PyObject_Dir(PyObject *); 432 433 /* Pickle support. */ 434 #ifndef Py_LIMITED_API 435 PyAPI_FUNC(PyObject *) _PyObject_GetState(PyObject *); 436 #endif 437 438 439 /* Helpers for printing recursive container types */ 440 PyAPI_FUNC(int) Py_ReprEnter(PyObject *); 441 PyAPI_FUNC(void) Py_ReprLeave(PyObject *); 442 443 /* Flag bits for printing: */ 444 #define Py_PRINT_RAW 1 /* No string quotes etc. */ 445 446 /* 447 Type flags (tp_flags) 448 449 These flags are used to change expected features and behavior for a 450 particular type. 451 452 Arbitration of the flag bit positions will need to be coordinated among 453 all extension writers who publicly release their extensions (this will 454 be fewer than you might expect!). 455 456 Most flags were removed as of Python 3.0 to make room for new flags. (Some 457 flags are not for backwards compatibility but to indicate the presence of an 458 optional feature; these flags remain of course.) 459 460 Type definitions should use Py_TPFLAGS_DEFAULT for their tp_flags value. 461 462 Code can use PyType_HasFeature(type_ob, flag_value) to test whether the 463 given type object has a specified feature. 464 */ 465 466 #ifndef Py_LIMITED_API 467 468 /* Track types initialized using _PyStaticType_InitBuiltin(). */ 469 #define _Py_TPFLAGS_STATIC_BUILTIN (1 << 1) 470 471 /* Placement of weakref pointers are managed by the VM, not by the type. 472 * The VM will automatically set tp_weaklistoffset. 473 */ 474 #define Py_TPFLAGS_MANAGED_WEAKREF (1 << 3) 475 476 /* Placement of dict (and values) pointers are managed by the VM, not by the type. 477 * The VM will automatically set tp_dictoffset. 478 */ 479 #define Py_TPFLAGS_MANAGED_DICT (1 << 4) 480 481 #define Py_TPFLAGS_PREHEADER (Py_TPFLAGS_MANAGED_WEAKREF | Py_TPFLAGS_MANAGED_DICT) 482 483 /* Set if instances of the type object are treated as sequences for pattern matching */ 484 #define Py_TPFLAGS_SEQUENCE (1 << 5) 485 /* Set if instances of the type object are treated as mappings for pattern matching */ 486 #define Py_TPFLAGS_MAPPING (1 << 6) 487 #endif 488 489 /* Disallow creating instances of the type: set tp_new to NULL and don't create 490 * the "__new__" key in the type dictionary. */ 491 #define Py_TPFLAGS_DISALLOW_INSTANTIATION (1UL << 7) 492 493 /* Set if the type object is immutable: type attributes cannot be set nor deleted */ 494 #define Py_TPFLAGS_IMMUTABLETYPE (1UL << 8) 495 496 /* Set if the type object is dynamically allocated */ 497 #define Py_TPFLAGS_HEAPTYPE (1UL << 9) 498 499 /* Set if the type allows subclassing */ 500 #define Py_TPFLAGS_BASETYPE (1UL << 10) 501 502 /* Set if the type implements the vectorcall protocol (PEP 590) */ 503 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030C0000 504 #define Py_TPFLAGS_HAVE_VECTORCALL (1UL << 11) 505 #ifndef Py_LIMITED_API 506 // Backwards compatibility alias for API that was provisional in Python 3.8 507 #define _Py_TPFLAGS_HAVE_VECTORCALL Py_TPFLAGS_HAVE_VECTORCALL 508 #endif 509 #endif 510 511 /* Set if the type is 'ready' -- fully initialized */ 512 #define Py_TPFLAGS_READY (1UL << 12) 513 514 /* Set while the type is being 'readied', to prevent recursive ready calls */ 515 #define Py_TPFLAGS_READYING (1UL << 13) 516 517 /* Objects support garbage collection (see objimpl.h) */ 518 #define Py_TPFLAGS_HAVE_GC (1UL << 14) 519 520 /* These two bits are preserved for Stackless Python, next after this is 17 */ 521 #ifdef STACKLESS 522 #define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION (3UL << 15) 523 #else 524 #define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION 0 525 #endif 526 527 /* Objects behave like an unbound method */ 528 #define Py_TPFLAGS_METHOD_DESCRIPTOR (1UL << 17) 529 530 /* Object has up-to-date type attribute cache */ 531 #define Py_TPFLAGS_VALID_VERSION_TAG (1UL << 19) 532 533 /* Type is abstract and cannot be instantiated */ 534 #define Py_TPFLAGS_IS_ABSTRACT (1UL << 20) 535 536 // This undocumented flag gives certain built-ins their unique pattern-matching 537 // behavior, which allows a single positional subpattern to match against the 538 // subject itself (rather than a mapped attribute on it): 539 #define _Py_TPFLAGS_MATCH_SELF (1UL << 22) 540 541 /* Items (ob_size*tp_itemsize) are found at the end of an instance's memory */ 542 #define Py_TPFLAGS_ITEMS_AT_END (1UL << 23) 543 544 /* These flags are used to determine if a type is a subclass. */ 545 #define Py_TPFLAGS_LONG_SUBCLASS (1UL << 24) 546 #define Py_TPFLAGS_LIST_SUBCLASS (1UL << 25) 547 #define Py_TPFLAGS_TUPLE_SUBCLASS (1UL << 26) 548 #define Py_TPFLAGS_BYTES_SUBCLASS (1UL << 27) 549 #define Py_TPFLAGS_UNICODE_SUBCLASS (1UL << 28) 550 #define Py_TPFLAGS_DICT_SUBCLASS (1UL << 29) 551 #define Py_TPFLAGS_BASE_EXC_SUBCLASS (1UL << 30) 552 #define Py_TPFLAGS_TYPE_SUBCLASS (1UL << 31) 553 554 #define Py_TPFLAGS_DEFAULT ( \ 555 Py_TPFLAGS_HAVE_STACKLESS_EXTENSION | \ 556 0) 557 558 /* NOTE: Some of the following flags reuse lower bits (removed as part of the 559 * Python 3.0 transition). */ 560 561 /* The following flags are kept for compatibility; in previous 562 * versions they indicated presence of newer tp_* fields on the 563 * type struct. 564 * Starting with 3.8, binary compatibility of C extensions across 565 * feature releases of Python is not supported anymore (except when 566 * using the stable ABI, in which all classes are created dynamically, 567 * using the interpreter's memory layout.) 568 * Note that older extensions using the stable ABI set these flags, 569 * so the bits must not be repurposed. 570 */ 571 #define Py_TPFLAGS_HAVE_FINALIZE (1UL << 0) 572 #define Py_TPFLAGS_HAVE_VERSION_TAG (1UL << 18) 573 574 575 /* 576 The macros Py_INCREF(op) and Py_DECREF(op) are used to increment or decrement 577 reference counts. Py_DECREF calls the object's deallocator function when 578 the refcount falls to 0; for 579 objects that don't contain references to other objects or heap memory 580 this can be the standard function free(). Both macros can be used 581 wherever a void expression is allowed. The argument must not be a 582 NULL pointer. If it may be NULL, use Py_XINCREF/Py_XDECREF instead. 583 The macro _Py_NewReference(op) initialize reference counts to 1, and 584 in special builds (Py_REF_DEBUG, Py_TRACE_REFS) performs additional 585 bookkeeping appropriate to the special build. 586 587 We assume that the reference count field can never overflow; this can 588 be proven when the size of the field is the same as the pointer size, so 589 we ignore the possibility. Provided a C int is at least 32 bits (which 590 is implicitly assumed in many parts of this code), that's enough for 591 about 2**31 references to an object. 592 593 XXX The following became out of date in Python 2.2, but I'm not sure 594 XXX what the full truth is now. Certainly, heap-allocated type objects 595 XXX can and should be deallocated. 596 Type objects should never be deallocated; the type pointer in an object 597 is not considered to be a reference to the type object, to save 598 complications in the deallocation function. (This is actually a 599 decision that's up to the implementer of each new type so if you want, 600 you can count such references to the type object.) 601 */ 602 603 #if defined(Py_REF_DEBUG) && !defined(Py_LIMITED_API) 604 PyAPI_FUNC(void) _Py_NegativeRefcount(const char *filename, int lineno, 605 PyObject *op); 606 PyAPI_FUNC(void) _Py_INCREF_IncRefTotal(void); 607 PyAPI_FUNC(void) _Py_DECREF_DecRefTotal(void); 608 #endif // Py_REF_DEBUG && !Py_LIMITED_API 609 610 PyAPI_FUNC(void) _Py_Dealloc(PyObject *); 611 612 /* 613 These are provided as conveniences to Python runtime embedders, so that 614 they can have object code that is not dependent on Python compilation flags. 615 */ 616 PyAPI_FUNC(void) Py_IncRef(PyObject *); 617 PyAPI_FUNC(void) Py_DecRef(PyObject *); 618 619 // Similar to Py_IncRef() and Py_DecRef() but the argument must be non-NULL. 620 // Private functions used by Py_INCREF() and Py_DECREF(). 621 PyAPI_FUNC(void) _Py_IncRef(PyObject *); 622 PyAPI_FUNC(void) _Py_DecRef(PyObject *); 623 624 static inline Py_ALWAYS_INLINE void Py_INCREF(PyObject *op) 625 { 626 #if defined(Py_LIMITED_API) && (Py_LIMITED_API+0 >= 0x030c0000 || defined(Py_REF_DEBUG)) 627 // Stable ABI implements Py_INCREF() as a function call on limited C API 628 // version 3.12 and newer, and on Python built in debug mode. _Py_IncRef() 629 // was added to Python 3.10.0a7, use Py_IncRef() on older Python versions. 630 // Py_IncRef() accepts NULL whereas _Py_IncRef() doesn't. 631 # if Py_LIMITED_API+0 >= 0x030a00A7 632 _Py_IncRef(op); 633 # else 634 Py_IncRef(op); 635 # endif 636 #else 637 // Non-limited C API and limited C API for Python 3.9 and older access 638 // directly PyObject.ob_refcnt. 639 #if SIZEOF_VOID_P > 4 640 // Portable saturated add, branching on the carry flag and set low bits 641 PY_UINT32_T cur_refcnt = op->ob_refcnt_split[PY_BIG_ENDIAN]; 642 PY_UINT32_T new_refcnt = cur_refcnt + 1; 643 if (new_refcnt == 0) { 644 return; 645 } 646 op->ob_refcnt_split[PY_BIG_ENDIAN] = new_refcnt; 647 #else 648 // Explicitly check immortality against the immortal value 649 if (_Py_IsImmortal(op)) { 650 return; 651 } 652 op->ob_refcnt++; 653 #endif 654 _Py_INCREF_STAT_INC(); 655 #ifdef Py_REF_DEBUG 656 _Py_INCREF_IncRefTotal(); 657 #endif 658 #endif 659 } 660 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000 661 # define Py_INCREF(op) Py_INCREF(_PyObject_CAST(op)) 662 #endif 663 664 #if defined(Py_LIMITED_API) && (Py_LIMITED_API+0 >= 0x030c0000 || defined(Py_REF_DEBUG)) 665 // Stable ABI implements Py_DECREF() as a function call on limited C API 666 // version 3.12 and newer, and on Python built in debug mode. _Py_DecRef() was 667 // added to Python 3.10.0a7, use Py_DecRef() on older Python versions. 668 // Py_DecRef() accepts NULL whereas _Py_IncRef() doesn't. 669 static inline void Py_DECREF(PyObject *op) { 670 # if Py_LIMITED_API+0 >= 0x030a00A7 671 _Py_DecRef(op); 672 # else 673 Py_DecRef(op); 674 # endif 675 } 676 #define Py_DECREF(op) Py_DECREF(_PyObject_CAST(op)) 677 678 #elif defined(Py_REF_DEBUG) 679 static inline void Py_DECREF(const char *filename, int lineno, PyObject *op) 680 { 681 if (op->ob_refcnt <= 0) { 682 _Py_NegativeRefcount(filename, lineno, op); 683 } 684 if (_Py_IsImmortal(op)) { 685 return; 686 } 687 _Py_DECREF_STAT_INC(); 688 _Py_DECREF_DecRefTotal(); 689 if (--op->ob_refcnt == 0) { 690 _Py_Dealloc(op); 691 } 692 } 693 #define Py_DECREF(op) Py_DECREF(__FILE__, __LINE__, _PyObject_CAST(op)) 694 695 #else 696 static inline Py_ALWAYS_INLINE void Py_DECREF(PyObject *op) 697 { 698 // Non-limited C API and limited C API for Python 3.9 and older access 699 // directly PyObject.ob_refcnt. 700 if (_Py_IsImmortal(op)) { 701 return; 702 } 703 _Py_DECREF_STAT_INC(); 704 if (--op->ob_refcnt == 0) { 705 _Py_Dealloc(op); 706 } 707 } 708 #define Py_DECREF(op) Py_DECREF(_PyObject_CAST(op)) 709 #endif 710 711 712 /* Safely decref `op` and set `op` to NULL, especially useful in tp_clear 713 * and tp_dealloc implementations. 714 * 715 * Note that "the obvious" code can be deadly: 716 * 717 * Py_XDECREF(op); 718 * op = NULL; 719 * 720 * Typically, `op` is something like self->containee, and `self` is done 721 * using its `containee` member. In the code sequence above, suppose 722 * `containee` is non-NULL with a refcount of 1. Its refcount falls to 723 * 0 on the first line, which can trigger an arbitrary amount of code, 724 * possibly including finalizers (like __del__ methods or weakref callbacks) 725 * coded in Python, which in turn can release the GIL and allow other threads 726 * to run, etc. Such code may even invoke methods of `self` again, or cause 727 * cyclic gc to trigger, but-- oops! --self->containee still points to the 728 * object being torn down, and it may be in an insane state while being torn 729 * down. This has in fact been a rich historic source of miserable (rare & 730 * hard-to-diagnose) segfaulting (and other) bugs. 731 * 732 * The safe way is: 733 * 734 * Py_CLEAR(op); 735 * 736 * That arranges to set `op` to NULL _before_ decref'ing, so that any code 737 * triggered as a side-effect of `op` getting torn down no longer believes 738 * `op` points to a valid object. 739 * 740 * There are cases where it's safe to use the naive code, but they're brittle. 741 * For example, if `op` points to a Python integer, you know that destroying 742 * one of those can't cause problems -- but in part that relies on that 743 * Python integers aren't currently weakly referencable. Best practice is 744 * to use Py_CLEAR() even if you can't think of a reason for why you need to. 745 * 746 * gh-98724: Use a temporary variable to only evaluate the macro argument once, 747 * to avoid the duplication of side effects if the argument has side effects. 748 * 749 * gh-99701: If the PyObject* type is used with casting arguments to PyObject*, 750 * the code can be miscompiled with strict aliasing because of type punning. 751 * With strict aliasing, a compiler considers that two pointers of different 752 * types cannot read or write the same memory which enables optimization 753 * opportunities. 754 * 755 * If available, use _Py_TYPEOF() to use the 'op' type for temporary variables, 756 * and so avoid type punning. Otherwise, use memcpy() which causes type erasure 757 * and so prevents the compiler to reuse an old cached 'op' value after 758 * Py_CLEAR(). 759 */ 760 #ifdef _Py_TYPEOF 761 #define Py_CLEAR(op) \ 762 do { \ 763 _Py_TYPEOF(op)* _tmp_op_ptr = &(op); \ 764 _Py_TYPEOF(op) _tmp_old_op = (*_tmp_op_ptr); \ 765 if (_tmp_old_op != NULL) { \ 766 *_tmp_op_ptr = _Py_NULL; \ 767 Py_DECREF(_tmp_old_op); \ 768 } \ 769 } while (0) 770 #else 771 #define Py_CLEAR(op) \ 772 do { \ 773 PyObject **_tmp_op_ptr = _Py_CAST(PyObject**, &(op)); \ 774 PyObject *_tmp_old_op = (*_tmp_op_ptr); \ 775 if (_tmp_old_op != NULL) { \ 776 PyObject *_null_ptr = _Py_NULL; \ 777 memcpy(_tmp_op_ptr, &_null_ptr, sizeof(PyObject*)); \ 778 Py_DECREF(_tmp_old_op); \ 779 } \ 780 } while (0) 781 #endif 782 783 784 /* Function to use in case the object pointer can be NULL: */ 785 static inline void Py_XINCREF(PyObject *op) 786 { 787 if (op != _Py_NULL) { 788 Py_INCREF(op); 789 } 790 } 791 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000 792 # define Py_XINCREF(op) Py_XINCREF(_PyObject_CAST(op)) 793 #endif 794 795 static inline void Py_XDECREF(PyObject *op) 796 { 797 if (op != _Py_NULL) { 798 Py_DECREF(op); 799 } 800 } 801 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000 802 # define Py_XDECREF(op) Py_XDECREF(_PyObject_CAST(op)) 803 #endif 804 805 // Create a new strong reference to an object: 806 // increment the reference count of the object and return the object. 807 PyAPI_FUNC(PyObject*) Py_NewRef(PyObject *obj); 808 809 // Similar to Py_NewRef(), but the object can be NULL. 810 PyAPI_FUNC(PyObject*) Py_XNewRef(PyObject *obj); 811 812 static inline PyObject* _Py_NewRef(PyObject *obj) 813 { 814 Py_INCREF(obj); 815 return obj; 816 } 817 818 static inline PyObject* _Py_XNewRef(PyObject *obj) 819 { 820 Py_XINCREF(obj); 821 return obj; 822 } 823 824 // Py_NewRef() and Py_XNewRef() are exported as functions for the stable ABI. 825 // Names overridden with macros by static inline functions for best 826 // performances. 827 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000 828 # define Py_NewRef(obj) _Py_NewRef(_PyObject_CAST(obj)) 829 # define Py_XNewRef(obj) _Py_XNewRef(_PyObject_CAST(obj)) 830 #else 831 # define Py_NewRef(obj) _Py_NewRef(obj) 832 # define Py_XNewRef(obj) _Py_XNewRef(obj) 833 #endif 834 835 836 /* 837 _Py_NoneStruct is an object of undefined type which can be used in contexts 838 where NULL (nil) is not suitable (since NULL often means 'error'). 839 840 Don't forget to apply Py_INCREF() when returning this value!!! 841 */ 842 PyAPI_DATA(PyObject) _Py_NoneStruct; /* Don't use this directly */ 843 #define Py_None (&_Py_NoneStruct) 844 845 // Test if an object is the None singleton, the same as "x is None" in Python. 846 PyAPI_FUNC(int) Py_IsNone(PyObject *x); 847 #define Py_IsNone(x) Py_Is((x), Py_None) 848 849 /* Macro for returning Py_None from a function */ 850 #define Py_RETURN_NONE return Py_None 851 852 /* 853 Py_NotImplemented is a singleton used to signal that an operation is 854 not implemented for a given type combination. 855 */ 856 PyAPI_DATA(PyObject) _Py_NotImplementedStruct; /* Don't use this directly */ 857 #define Py_NotImplemented (&_Py_NotImplementedStruct) 858 859 /* Macro for returning Py_NotImplemented from a function */ 860 #define Py_RETURN_NOTIMPLEMENTED return Py_NotImplemented 861 862 /* Rich comparison opcodes */ 863 #define Py_LT 0 864 #define Py_LE 1 865 #define Py_EQ 2 866 #define Py_NE 3 867 #define Py_GT 4 868 #define Py_GE 5 869 870 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030A0000 871 /* Result of calling PyIter_Send */ 872 typedef enum { 873 PYGEN_RETURN = 0, 874 PYGEN_ERROR = -1, 875 PYGEN_NEXT = 1, 876 } PySendResult; 877 #endif 878 879 /* 880 * Macro for implementing rich comparisons 881 * 882 * Needs to be a macro because any C-comparable type can be used. 883 */ 884 #define Py_RETURN_RICHCOMPARE(val1, val2, op) \ 885 do { \ 886 switch (op) { \ 887 case Py_EQ: if ((val1) == (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE; \ 888 case Py_NE: if ((val1) != (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE; \ 889 case Py_LT: if ((val1) < (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE; \ 890 case Py_GT: if ((val1) > (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE; \ 891 case Py_LE: if ((val1) <= (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE; \ 892 case Py_GE: if ((val1) >= (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE; \ 893 default: \ 894 Py_UNREACHABLE(); \ 895 } \ 896 } while (0) 897 898 899 /* 900 More conventions 901 ================ 902 903 Argument Checking 904 ----------------- 905 906 Functions that take objects as arguments normally don't check for nil 907 arguments, but they do check the type of the argument, and return an 908 error if the function doesn't apply to the type. 909 910 Failure Modes 911 ------------- 912 913 Functions may fail for a variety of reasons, including running out of 914 memory. This is communicated to the caller in two ways: an error string 915 is set (see errors.h), and the function result differs: functions that 916 normally return a pointer return NULL for failure, functions returning 917 an integer return -1 (which could be a legal return value too!), and 918 other functions return 0 for success and -1 for failure. 919 Callers should always check for errors before using the result. If 920 an error was set, the caller must either explicitly clear it, or pass 921 the error on to its caller. 922 923 Reference Counts 924 ---------------- 925 926 It takes a while to get used to the proper usage of reference counts. 927 928 Functions that create an object set the reference count to 1; such new 929 objects must be stored somewhere or destroyed again with Py_DECREF(). 930 Some functions that 'store' objects, such as PyTuple_SetItem() and 931 PyList_SetItem(), 932 don't increment the reference count of the object, since the most 933 frequent use is to store a fresh object. Functions that 'retrieve' 934 objects, such as PyTuple_GetItem() and PyDict_GetItemString(), also 935 don't increment 936 the reference count, since most frequently the object is only looked at 937 quickly. Thus, to retrieve an object and store it again, the caller 938 must call Py_INCREF() explicitly. 939 940 NOTE: functions that 'consume' a reference count, like 941 PyList_SetItem(), consume the reference even if the object wasn't 942 successfully stored, to simplify error handling. 943 944 It seems attractive to make other functions that take an object as 945 argument consume a reference count; however, this may quickly get 946 confusing (even the current practice is already confusing). Consider 947 it carefully, it may save lots of calls to Py_INCREF() and Py_DECREF() at 948 times. 949 */ 950 951 #ifndef Py_LIMITED_API 952 # define Py_CPYTHON_OBJECT_H 953 # include "cpython/object.h" 954 # undef Py_CPYTHON_OBJECT_H 955 #endif 956 957 958 static inline int 959 PyType_HasFeature(PyTypeObject *type, unsigned long feature) 960 { 961 unsigned long flags; 962 #ifdef Py_LIMITED_API 963 // PyTypeObject is opaque in the limited C API 964 flags = PyType_GetFlags(type); 965 #else 966 flags = type->tp_flags; 967 #endif 968 return ((flags & feature) != 0); 969 } 970 971 #define PyType_FastSubclass(type, flag) PyType_HasFeature((type), (flag)) 972 973 static inline int PyType_Check(PyObject *op) { 974 return PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_TYPE_SUBCLASS); 975 } 976 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000 977 # define PyType_Check(op) PyType_Check(_PyObject_CAST(op)) 978 #endif 979 980 #define _PyType_CAST(op) \ 981 (assert(PyType_Check(op)), _Py_CAST(PyTypeObject*, (op))) 982 983 static inline int PyType_CheckExact(PyObject *op) { 984 return Py_IS_TYPE(op, &PyType_Type); 985 } 986 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000 987 # define PyType_CheckExact(op) PyType_CheckExact(_PyObject_CAST(op)) 988 #endif 989 990 #ifdef __cplusplus 991 } 992 #endif 993 #endif // !Py_OBJECT_H
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