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The C and C++ Include Header Files
/usr/include/python3.10/object.h
$ cat -n /usr/include/python3.10/object.h 1 #ifndef Py_OBJECT_H 2 #define Py_OBJECT_H 3 4 #ifdef __cplusplus 5 extern "C" { 6 #endif 7 8 9 /* Object and type object interface */ 10 11 /* 12 Objects are structures allocated on the heap. Special rules apply to 13 the use of objects to ensure they are properly garbage-collected. 14 Objects are never allocated statically or on the stack; they must be 15 accessed through special macros and functions only. (Type objects are 16 exceptions to the first rule; the standard types are represented by 17 statically initialized type objects, although work on type/class unification 18 for Python 2.2 made it possible to have heap-allocated type objects too). 19 20 An object has a 'reference count' that is increased or decreased when a 21 pointer to the object is copied or deleted; when the reference count 22 reaches zero there are no references to the object left and it can be 23 removed from the heap. 24 25 An object has a 'type' that determines what it represents and what kind 26 of data it contains. An object's type is fixed when it is created. 27 Types themselves are represented as objects; an object contains a 28 pointer to the corresponding type object. The type itself has a type 29 pointer pointing to the object representing the type 'type', which 30 contains a pointer to itself!. 31 32 Objects do not float around in memory; once allocated an object keeps 33 the same size and address. Objects that must hold variable-size data 34 can contain pointers to variable-size parts of the object. Not all 35 objects of the same type have the same size; but the size cannot change 36 after allocation. (These restrictions are made so a reference to an 37 object can be simply a pointer -- moving an object would require 38 updating all the pointers, and changing an object's size would require 39 moving it if there was another object right next to it.) 40 41 Objects are always accessed through pointers of the type 'PyObject *'. 42 The type 'PyObject' is a structure that only contains the reference count 43 and the type pointer. The actual memory allocated for an object 44 contains other data that can only be accessed after casting the pointer 45 to a pointer to a longer structure type. This longer type must start 46 with the reference count and type fields; the macro PyObject_HEAD should be 47 used for this (to accommodate for future changes). The implementation 48 of a particular object type can cast the object pointer to the proper 49 type and back. 50 51 A standard interface exists for objects that contain an array of items 52 whose size is determined when the object is allocated. 53 */ 54 55 /* Py_DEBUG implies Py_REF_DEBUG. */ 56 #if defined(Py_DEBUG) && !defined(Py_REF_DEBUG) 57 # define Py_REF_DEBUG 58 #endif 59 60 #if defined(Py_LIMITED_API) && defined(Py_TRACE_REFS) 61 # error Py_LIMITED_API is incompatible with Py_TRACE_REFS 62 #endif 63 64 /* PyTypeObject structure is defined in cpython/object.h. 65 In Py_LIMITED_API, PyTypeObject is an opaque structure. */ 66 typedef struct _typeobject PyTypeObject; 67 68 #ifdef Py_TRACE_REFS 69 /* Define pointers to support a doubly-linked list of all live heap objects. */ 70 #define _PyObject_HEAD_EXTRA \ 71 struct _object *_ob_next; \ 72 struct _object *_ob_prev; 73 74 #define _PyObject_EXTRA_INIT 0, 0, 75 76 #else 77 # define _PyObject_HEAD_EXTRA 78 # define _PyObject_EXTRA_INIT 79 #endif 80 81 /* PyObject_HEAD defines the initial segment of every PyObject. */ 82 #define PyObject_HEAD PyObject ob_base; 83 84 #define PyObject_HEAD_INIT(type) \ 85 { _PyObject_EXTRA_INIT \ 86 1, type }, 87 88 #define PyVarObject_HEAD_INIT(type, size) \ 89 { PyObject_HEAD_INIT(type) size }, 90 91 /* PyObject_VAR_HEAD defines the initial segment of all variable-size 92 * container objects. These end with a declaration of an array with 1 93 * element, but enough space is malloc'ed so that the array actually 94 * has room for ob_size elements. Note that ob_size is an element count, 95 * not necessarily a byte count. 96 */ 97 #define PyObject_VAR_HEAD PyVarObject ob_base; 98 #define Py_INVALID_SIZE (Py_ssize_t)-1 99 100 /* Nothing is actually declared to be a PyObject, but every pointer to 101 * a Python object can be cast to a PyObject*. This is inheritance built 102 * by hand. Similarly every pointer to a variable-size Python object can, 103 * in addition, be cast to PyVarObject*. 104 */ 105 typedef struct _object { 106 _PyObject_HEAD_EXTRA 107 Py_ssize_t ob_refcnt; 108 PyTypeObject *ob_type; 109 } PyObject; 110 111 /* Cast argument to PyObject* type. */ 112 #define _PyObject_CAST(op) ((PyObject*)(op)) 113 #define _PyObject_CAST_CONST(op) ((const PyObject*)(op)) 114 115 typedef struct { 116 PyObject ob_base; 117 Py_ssize_t ob_size; /* Number of items in variable part */ 118 } PyVarObject; 119 120 /* Cast argument to PyVarObject* type. */ 121 #define _PyVarObject_CAST(op) ((PyVarObject*)(op)) 122 #define _PyVarObject_CAST_CONST(op) ((const PyVarObject*)(op)) 123 124 125 // Test if the 'x' object is the 'y' object, the same as "x is y" in Python. 126 PyAPI_FUNC(int) Py_Is(PyObject *x, PyObject *y); 127 #define Py_Is(x, y) ((x) == (y)) 128 129 130 static inline Py_ssize_t _Py_REFCNT(const PyObject *ob) { 131 return ob->ob_refcnt; 132 } 133 #define Py_REFCNT(ob) _Py_REFCNT(_PyObject_CAST_CONST(ob)) 134 135 136 // bpo-39573: The Py_SET_TYPE() function must be used to set an object type. 137 #define Py_TYPE(ob) (_PyObject_CAST(ob)->ob_type) 138 139 // bpo-39573: The Py_SET_SIZE() function must be used to set an object size. 140 #define Py_SIZE(ob) (_PyVarObject_CAST(ob)->ob_size) 141 142 143 static inline int _Py_IS_TYPE(const PyObject *ob, const PyTypeObject *type) { 144 // bpo-44378: Don't use Py_TYPE() since Py_TYPE() requires a non-const 145 // object. 146 return ob->ob_type == type; 147 } 148 #define Py_IS_TYPE(ob, type) _Py_IS_TYPE(_PyObject_CAST_CONST(ob), type) 149 150 151 static inline void _Py_SET_REFCNT(PyObject *ob, Py_ssize_t refcnt) { 152 ob->ob_refcnt = refcnt; 153 } 154 #define Py_SET_REFCNT(ob, refcnt) _Py_SET_REFCNT(_PyObject_CAST(ob), refcnt) 155 156 157 static inline void _Py_SET_TYPE(PyObject *ob, PyTypeObject *type) { 158 ob->ob_type = type; 159 } 160 #define Py_SET_TYPE(ob, type) _Py_SET_TYPE(_PyObject_CAST(ob), type) 161 162 163 static inline void _Py_SET_SIZE(PyVarObject *ob, Py_ssize_t size) { 164 ob->ob_size = size; 165 } 166 #define Py_SET_SIZE(ob, size) _Py_SET_SIZE(_PyVarObject_CAST(ob), size) 167 168 169 /* 170 Type objects contain a string containing the type name (to help somewhat 171 in debugging), the allocation parameters (see PyObject_New() and 172 PyObject_NewVar()), 173 and methods for accessing objects of the type. Methods are optional, a 174 nil pointer meaning that particular kind of access is not available for 175 this type. The Py_DECREF() macro uses the tp_dealloc method without 176 checking for a nil pointer; it should always be implemented except if 177 the implementation can guarantee that the reference count will never 178 reach zero (e.g., for statically allocated type objects). 179 180 NB: the methods for certain type groups are now contained in separate 181 method blocks. 182 */ 183 184 typedef PyObject * (*unaryfunc)(PyObject *); 185 typedef PyObject * (*binaryfunc)(PyObject *, PyObject *); 186 typedef PyObject * (*ternaryfunc)(PyObject *, PyObject *, PyObject *); 187 typedef int (*inquiry)(PyObject *); 188 typedef Py_ssize_t (*lenfunc)(PyObject *); 189 typedef PyObject *(*ssizeargfunc)(PyObject *, Py_ssize_t); 190 typedef PyObject *(*ssizessizeargfunc)(PyObject *, Py_ssize_t, Py_ssize_t); 191 typedef int(*ssizeobjargproc)(PyObject *, Py_ssize_t, PyObject *); 192 typedef int(*ssizessizeobjargproc)(PyObject *, Py_ssize_t, Py_ssize_t, PyObject *); 193 typedef int(*objobjargproc)(PyObject *, PyObject *, PyObject *); 194 195 typedef int (*objobjproc)(PyObject *, PyObject *); 196 typedef int (*visitproc)(PyObject *, void *); 197 typedef int (*traverseproc)(PyObject *, visitproc, void *); 198 199 200 typedef void (*freefunc)(void *); 201 typedef void (*destructor)(PyObject *); 202 typedef PyObject *(*getattrfunc)(PyObject *, char *); 203 typedef PyObject *(*getattrofunc)(PyObject *, PyObject *); 204 typedef int (*setattrfunc)(PyObject *, char *, PyObject *); 205 typedef int (*setattrofunc)(PyObject *, PyObject *, PyObject *); 206 typedef PyObject *(*reprfunc)(PyObject *); 207 typedef Py_hash_t (*hashfunc)(PyObject *); 208 typedef PyObject *(*richcmpfunc) (PyObject *, PyObject *, int); 209 typedef PyObject *(*getiterfunc) (PyObject *); 210 typedef PyObject *(*iternextfunc) (PyObject *); 211 typedef PyObject *(*descrgetfunc) (PyObject *, PyObject *, PyObject *); 212 typedef int (*descrsetfunc) (PyObject *, PyObject *, PyObject *); 213 typedef int (*initproc)(PyObject *, PyObject *, PyObject *); 214 typedef PyObject *(*newfunc)(PyTypeObject *, PyObject *, PyObject *); 215 typedef PyObject *(*allocfunc)(PyTypeObject *, Py_ssize_t); 216 217 typedef struct{ 218 int slot; /* slot id, see below */ 219 void *pfunc; /* function pointer */ 220 } PyType_Slot; 221 222 typedef struct{ 223 const char* name; 224 int basicsize; 225 int itemsize; 226 unsigned int flags; 227 PyType_Slot *slots; /* terminated by slot==0. */ 228 } PyType_Spec; 229 230 PyAPI_FUNC(PyObject*) PyType_FromSpec(PyType_Spec*); 231 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03030000 232 PyAPI_FUNC(PyObject*) PyType_FromSpecWithBases(PyType_Spec*, PyObject*); 233 #endif 234 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03040000 235 PyAPI_FUNC(void*) PyType_GetSlot(PyTypeObject*, int); 236 #endif 237 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03090000 238 PyAPI_FUNC(PyObject*) PyType_FromModuleAndSpec(PyObject *, PyType_Spec *, PyObject *); 239 PyAPI_FUNC(PyObject *) PyType_GetModule(struct _typeobject *); 240 PyAPI_FUNC(void *) PyType_GetModuleState(struct _typeobject *); 241 #endif 242 243 /* Generic type check */ 244 PyAPI_FUNC(int) PyType_IsSubtype(PyTypeObject *, PyTypeObject *); 245 246 static inline int _PyObject_TypeCheck(PyObject *ob, PyTypeObject *type) { 247 return Py_IS_TYPE(ob, type) || PyType_IsSubtype(Py_TYPE(ob), type); 248 } 249 #define PyObject_TypeCheck(ob, type) _PyObject_TypeCheck(_PyObject_CAST(ob), type) 250 251 PyAPI_DATA(PyTypeObject) PyType_Type; /* built-in 'type' */ 252 PyAPI_DATA(PyTypeObject) PyBaseObject_Type; /* built-in 'object' */ 253 PyAPI_DATA(PyTypeObject) PySuper_Type; /* built-in 'super' */ 254 255 PyAPI_FUNC(unsigned long) PyType_GetFlags(PyTypeObject*); 256 257 PyAPI_FUNC(int) PyType_Ready(PyTypeObject *); 258 PyAPI_FUNC(PyObject *) PyType_GenericAlloc(PyTypeObject *, Py_ssize_t); 259 PyAPI_FUNC(PyObject *) PyType_GenericNew(PyTypeObject *, 260 PyObject *, PyObject *); 261 PyAPI_FUNC(unsigned int) PyType_ClearCache(void); 262 PyAPI_FUNC(void) PyType_Modified(PyTypeObject *); 263 264 /* Generic operations on objects */ 265 PyAPI_FUNC(PyObject *) PyObject_Repr(PyObject *); 266 PyAPI_FUNC(PyObject *) PyObject_Str(PyObject *); 267 PyAPI_FUNC(PyObject *) PyObject_ASCII(PyObject *); 268 PyAPI_FUNC(PyObject *) PyObject_Bytes(PyObject *); 269 PyAPI_FUNC(PyObject *) PyObject_RichCompare(PyObject *, PyObject *, int); 270 PyAPI_FUNC(int) PyObject_RichCompareBool(PyObject *, PyObject *, int); 271 PyAPI_FUNC(PyObject *) PyObject_GetAttrString(PyObject *, const char *); 272 PyAPI_FUNC(int) PyObject_SetAttrString(PyObject *, const char *, PyObject *); 273 PyAPI_FUNC(int) PyObject_HasAttrString(PyObject *, const char *); 274 PyAPI_FUNC(PyObject *) PyObject_GetAttr(PyObject *, PyObject *); 275 PyAPI_FUNC(int) PyObject_SetAttr(PyObject *, PyObject *, PyObject *); 276 PyAPI_FUNC(int) PyObject_HasAttr(PyObject *, PyObject *); 277 PyAPI_FUNC(PyObject *) PyObject_SelfIter(PyObject *); 278 PyAPI_FUNC(PyObject *) PyObject_GenericGetAttr(PyObject *, PyObject *); 279 PyAPI_FUNC(int) PyObject_GenericSetAttr(PyObject *, PyObject *, PyObject *); 280 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03030000 281 PyAPI_FUNC(int) PyObject_GenericSetDict(PyObject *, PyObject *, void *); 282 #endif 283 PyAPI_FUNC(Py_hash_t) PyObject_Hash(PyObject *); 284 PyAPI_FUNC(Py_hash_t) PyObject_HashNotImplemented(PyObject *); 285 PyAPI_FUNC(int) PyObject_IsTrue(PyObject *); 286 PyAPI_FUNC(int) PyObject_Not(PyObject *); 287 PyAPI_FUNC(int) PyCallable_Check(PyObject *); 288 PyAPI_FUNC(void) PyObject_ClearWeakRefs(PyObject *); 289 290 /* PyObject_Dir(obj) acts like Python builtins.dir(obj), returning a 291 list of strings. PyObject_Dir(NULL) is like builtins.dir(), 292 returning the names of the current locals. In this case, if there are 293 no current locals, NULL is returned, and PyErr_Occurred() is false. 294 */ 295 PyAPI_FUNC(PyObject *) PyObject_Dir(PyObject *); 296 297 298 /* Helpers for printing recursive container types */ 299 PyAPI_FUNC(int) Py_ReprEnter(PyObject *); 300 PyAPI_FUNC(void) Py_ReprLeave(PyObject *); 301 302 /* Flag bits for printing: */ 303 #define Py_PRINT_RAW 1 /* No string quotes etc. */ 304 305 /* 306 Type flags (tp_flags) 307 308 These flags are used to change expected features and behavior for a 309 particular type. 310 311 Arbitration of the flag bit positions will need to be coordinated among 312 all extension writers who publicly release their extensions (this will 313 be fewer than you might expect!). 314 315 Most flags were removed as of Python 3.0 to make room for new flags. (Some 316 flags are not for backwards compatibility but to indicate the presence of an 317 optional feature; these flags remain of course.) 318 319 Type definitions should use Py_TPFLAGS_DEFAULT for their tp_flags value. 320 321 Code can use PyType_HasFeature(type_ob, flag_value) to test whether the 322 given type object has a specified feature. 323 */ 324 325 #ifndef Py_LIMITED_API 326 /* Set if instances of the type object are treated as sequences for pattern matching */ 327 #define Py_TPFLAGS_SEQUENCE (1 << 5) 328 /* Set if instances of the type object are treated as mappings for pattern matching */ 329 #define Py_TPFLAGS_MAPPING (1 << 6) 330 #endif 331 332 /* Disallow creating instances of the type: set tp_new to NULL and don't create 333 * the "__new__" key in the type dictionary. */ 334 #define Py_TPFLAGS_DISALLOW_INSTANTIATION (1UL << 7) 335 336 /* Set if the type object is immutable: type attributes cannot be set nor deleted */ 337 #define Py_TPFLAGS_IMMUTABLETYPE (1UL << 8) 338 339 /* Set if the type object is dynamically allocated */ 340 #define Py_TPFLAGS_HEAPTYPE (1UL << 9) 341 342 /* Set if the type allows subclassing */ 343 #define Py_TPFLAGS_BASETYPE (1UL << 10) 344 345 /* Set if the type implements the vectorcall protocol (PEP 590) */ 346 #ifndef Py_LIMITED_API 347 #define Py_TPFLAGS_HAVE_VECTORCALL (1UL << 11) 348 // Backwards compatibility alias for API that was provisional in Python 3.8 349 #define _Py_TPFLAGS_HAVE_VECTORCALL Py_TPFLAGS_HAVE_VECTORCALL 350 #endif 351 352 /* Set if the type is 'ready' -- fully initialized */ 353 #define Py_TPFLAGS_READY (1UL << 12) 354 355 /* Set while the type is being 'readied', to prevent recursive ready calls */ 356 #define Py_TPFLAGS_READYING (1UL << 13) 357 358 /* Objects support garbage collection (see objimpl.h) */ 359 #define Py_TPFLAGS_HAVE_GC (1UL << 14) 360 361 /* These two bits are preserved for Stackless Python, next after this is 17 */ 362 #ifdef STACKLESS 363 #define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION (3UL << 15) 364 #else 365 #define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION 0 366 #endif 367 368 /* Objects behave like an unbound method */ 369 #define Py_TPFLAGS_METHOD_DESCRIPTOR (1UL << 17) 370 371 /* Object has up-to-date type attribute cache */ 372 #define Py_TPFLAGS_VALID_VERSION_TAG (1UL << 19) 373 374 /* Type is abstract and cannot be instantiated */ 375 #define Py_TPFLAGS_IS_ABSTRACT (1UL << 20) 376 377 // This undocumented flag gives certain built-ins their unique pattern-matching 378 // behavior, which allows a single positional subpattern to match against the 379 // subject itself (rather than a mapped attribute on it): 380 #define _Py_TPFLAGS_MATCH_SELF (1UL << 22) 381 382 /* These flags are used to determine if a type is a subclass. */ 383 #define Py_TPFLAGS_LONG_SUBCLASS (1UL << 24) 384 #define Py_TPFLAGS_LIST_SUBCLASS (1UL << 25) 385 #define Py_TPFLAGS_TUPLE_SUBCLASS (1UL << 26) 386 #define Py_TPFLAGS_BYTES_SUBCLASS (1UL << 27) 387 #define Py_TPFLAGS_UNICODE_SUBCLASS (1UL << 28) 388 #define Py_TPFLAGS_DICT_SUBCLASS (1UL << 29) 389 #define Py_TPFLAGS_BASE_EXC_SUBCLASS (1UL << 30) 390 #define Py_TPFLAGS_TYPE_SUBCLASS (1UL << 31) 391 392 #define Py_TPFLAGS_DEFAULT ( \ 393 Py_TPFLAGS_HAVE_STACKLESS_EXTENSION | \ 394 0) 395 396 /* NOTE: Some of the following flags reuse lower bits (removed as part of the 397 * Python 3.0 transition). */ 398 399 /* The following flags are kept for compatibility; in previous 400 * versions they indicated presence of newer tp_* fields on the 401 * type struct. 402 * Starting with 3.8, binary compatibility of C extensions across 403 * feature releases of Python is not supported anymore (except when 404 * using the stable ABI, in which all classes are created dynamically, 405 * using the interpreter's memory layout.) 406 * Note that older extensions using the stable ABI set these flags, 407 * so the bits must not be repurposed. 408 */ 409 #define Py_TPFLAGS_HAVE_FINALIZE (1UL << 0) 410 #define Py_TPFLAGS_HAVE_VERSION_TAG (1UL << 18) 411 412 413 /* 414 The macros Py_INCREF(op) and Py_DECREF(op) are used to increment or decrement 415 reference counts. Py_DECREF calls the object's deallocator function when 416 the refcount falls to 0; for 417 objects that don't contain references to other objects or heap memory 418 this can be the standard function free(). Both macros can be used 419 wherever a void expression is allowed. The argument must not be a 420 NULL pointer. If it may be NULL, use Py_XINCREF/Py_XDECREF instead. 421 The macro _Py_NewReference(op) initialize reference counts to 1, and 422 in special builds (Py_REF_DEBUG, Py_TRACE_REFS) performs additional 423 bookkeeping appropriate to the special build. 424 425 We assume that the reference count field can never overflow; this can 426 be proven when the size of the field is the same as the pointer size, so 427 we ignore the possibility. Provided a C int is at least 32 bits (which 428 is implicitly assumed in many parts of this code), that's enough for 429 about 2**31 references to an object. 430 431 XXX The following became out of date in Python 2.2, but I'm not sure 432 XXX what the full truth is now. Certainly, heap-allocated type objects 433 XXX can and should be deallocated. 434 Type objects should never be deallocated; the type pointer in an object 435 is not considered to be a reference to the type object, to save 436 complications in the deallocation function. (This is actually a 437 decision that's up to the implementer of each new type so if you want, 438 you can count such references to the type object.) 439 */ 440 441 #ifdef Py_REF_DEBUG 442 PyAPI_DATA(Py_ssize_t) _Py_RefTotal; 443 PyAPI_FUNC(void) _Py_NegativeRefcount(const char *filename, int lineno, 444 PyObject *op); 445 #endif /* Py_REF_DEBUG */ 446 447 PyAPI_FUNC(void) _Py_Dealloc(PyObject *); 448 449 /* 450 These are provided as conveniences to Python runtime embedders, so that 451 they can have object code that is not dependent on Python compilation flags. 452 */ 453 PyAPI_FUNC(void) Py_IncRef(PyObject *); 454 PyAPI_FUNC(void) Py_DecRef(PyObject *); 455 456 // Similar to Py_IncRef() and Py_DecRef() but the argument must be non-NULL. 457 // Private functions used by Py_INCREF() and Py_DECREF(). 458 PyAPI_FUNC(void) _Py_IncRef(PyObject *); 459 PyAPI_FUNC(void) _Py_DecRef(PyObject *); 460 461 static inline void _Py_INCREF(PyObject *op) 462 { 463 #if defined(Py_REF_DEBUG) && defined(Py_LIMITED_API) && Py_LIMITED_API+0 >= 0x030A0000 464 // Stable ABI for Python 3.10 built in debug mode. 465 _Py_IncRef(op); 466 #else 467 // Non-limited C API and limited C API for Python 3.9 and older access 468 // directly PyObject.ob_refcnt. 469 #ifdef Py_REF_DEBUG 470 _Py_RefTotal++; 471 #endif 472 op->ob_refcnt++; 473 #endif 474 } 475 #define Py_INCREF(op) _Py_INCREF(_PyObject_CAST(op)) 476 477 static inline void _Py_DECREF( 478 #if defined(Py_REF_DEBUG) && !(defined(Py_LIMITED_API) && Py_LIMITED_API+0 >= 0x030A0000) 479 const char *filename, int lineno, 480 #endif 481 PyObject *op) 482 { 483 #if defined(Py_REF_DEBUG) && defined(Py_LIMITED_API) && Py_LIMITED_API+0 >= 0x030A0000 484 // Stable ABI for Python 3.10 built in debug mode. 485 _Py_DecRef(op); 486 #else 487 // Non-limited C API and limited C API for Python 3.9 and older access 488 // directly PyObject.ob_refcnt. 489 #ifdef Py_REF_DEBUG 490 _Py_RefTotal--; 491 #endif 492 if (--op->ob_refcnt != 0) { 493 #ifdef Py_REF_DEBUG 494 if (op->ob_refcnt < 0) { 495 _Py_NegativeRefcount(filename, lineno, op); 496 } 497 #endif 498 } 499 else { 500 _Py_Dealloc(op); 501 } 502 #endif 503 } 504 #if defined(Py_REF_DEBUG) && !(defined(Py_LIMITED_API) && Py_LIMITED_API+0 >= 0x030A0000) 505 # define Py_DECREF(op) _Py_DECREF(__FILE__, __LINE__, _PyObject_CAST(op)) 506 #else 507 # define Py_DECREF(op) _Py_DECREF(_PyObject_CAST(op)) 508 #endif 509 510 511 /* Safely decref `op` and set `op` to NULL, especially useful in tp_clear 512 * and tp_dealloc implementations. 513 * 514 * Note that "the obvious" code can be deadly: 515 * 516 * Py_XDECREF(op); 517 * op = NULL; 518 * 519 * Typically, `op` is something like self->containee, and `self` is done 520 * using its `containee` member. In the code sequence above, suppose 521 * `containee` is non-NULL with a refcount of 1. Its refcount falls to 522 * 0 on the first line, which can trigger an arbitrary amount of code, 523 * possibly including finalizers (like __del__ methods or weakref callbacks) 524 * coded in Python, which in turn can release the GIL and allow other threads 525 * to run, etc. Such code may even invoke methods of `self` again, or cause 526 * cyclic gc to trigger, but-- oops! --self->containee still points to the 527 * object being torn down, and it may be in an insane state while being torn 528 * down. This has in fact been a rich historic source of miserable (rare & 529 * hard-to-diagnose) segfaulting (and other) bugs. 530 * 531 * The safe way is: 532 * 533 * Py_CLEAR(op); 534 * 535 * That arranges to set `op` to NULL _before_ decref'ing, so that any code 536 * triggered as a side-effect of `op` getting torn down no longer believes 537 * `op` points to a valid object. 538 * 539 * There are cases where it's safe to use the naive code, but they're brittle. 540 * For example, if `op` points to a Python integer, you know that destroying 541 * one of those can't cause problems -- but in part that relies on that 542 * Python integers aren't currently weakly referencable. Best practice is 543 * to use Py_CLEAR() even if you can't think of a reason for why you need to. 544 */ 545 #define Py_CLEAR(op) \ 546 do { \ 547 PyObject *_py_tmp = _PyObject_CAST(op); \ 548 if (_py_tmp != NULL) { \ 549 (op) = NULL; \ 550 Py_DECREF(_py_tmp); \ 551 } \ 552 } while (0) 553 554 /* Function to use in case the object pointer can be NULL: */ 555 static inline void _Py_XINCREF(PyObject *op) 556 { 557 if (op != NULL) { 558 Py_INCREF(op); 559 } 560 } 561 562 #define Py_XINCREF(op) _Py_XINCREF(_PyObject_CAST(op)) 563 564 static inline void _Py_XDECREF(PyObject *op) 565 { 566 if (op != NULL) { 567 Py_DECREF(op); 568 } 569 } 570 571 #define Py_XDECREF(op) _Py_XDECREF(_PyObject_CAST(op)) 572 573 // Create a new strong reference to an object: 574 // increment the reference count of the object and return the object. 575 PyAPI_FUNC(PyObject*) Py_NewRef(PyObject *obj); 576 577 // Similar to Py_NewRef(), but the object can be NULL. 578 PyAPI_FUNC(PyObject*) Py_XNewRef(PyObject *obj); 579 580 static inline PyObject* _Py_NewRef(PyObject *obj) 581 { 582 Py_INCREF(obj); 583 return obj; 584 } 585 586 static inline PyObject* _Py_XNewRef(PyObject *obj) 587 { 588 Py_XINCREF(obj); 589 return obj; 590 } 591 592 // Py_NewRef() and Py_XNewRef() are exported as functions for the stable ABI. 593 // Names overridden with macros by static inline functions for best 594 // performances. 595 #define Py_NewRef(obj) _Py_NewRef(_PyObject_CAST(obj)) 596 #define Py_XNewRef(obj) _Py_XNewRef(_PyObject_CAST(obj)) 597 598 599 /* 600 _Py_NoneStruct is an object of undefined type which can be used in contexts 601 where NULL (nil) is not suitable (since NULL often means 'error'). 602 603 Don't forget to apply Py_INCREF() when returning this value!!! 604 */ 605 PyAPI_DATA(PyObject) _Py_NoneStruct; /* Don't use this directly */ 606 #define Py_None (&_Py_NoneStruct) 607 608 // Test if an object is the None singleton, the same as "x is None" in Python. 609 PyAPI_FUNC(int) Py_IsNone(PyObject *x); 610 #define Py_IsNone(x) Py_Is((x), Py_None) 611 612 /* Macro for returning Py_None from a function */ 613 #define Py_RETURN_NONE return Py_NewRef(Py_None) 614 615 /* 616 Py_NotImplemented is a singleton used to signal that an operation is 617 not implemented for a given type combination. 618 */ 619 PyAPI_DATA(PyObject) _Py_NotImplementedStruct; /* Don't use this directly */ 620 #define Py_NotImplemented (&_Py_NotImplementedStruct) 621 622 /* Macro for returning Py_NotImplemented from a function */ 623 #define Py_RETURN_NOTIMPLEMENTED return Py_NewRef(Py_NotImplemented) 624 625 /* Rich comparison opcodes */ 626 #define Py_LT 0 627 #define Py_LE 1 628 #define Py_EQ 2 629 #define Py_NE 3 630 #define Py_GT 4 631 #define Py_GE 5 632 633 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030A0000 634 /* Result of calling PyIter_Send */ 635 typedef enum { 636 PYGEN_RETURN = 0, 637 PYGEN_ERROR = -1, 638 PYGEN_NEXT = 1, 639 } PySendResult; 640 #endif 641 642 /* 643 * Macro for implementing rich comparisons 644 * 645 * Needs to be a macro because any C-comparable type can be used. 646 */ 647 #define Py_RETURN_RICHCOMPARE(val1, val2, op) \ 648 do { \ 649 switch (op) { \ 650 case Py_EQ: if ((val1) == (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE; \ 651 case Py_NE: if ((val1) != (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE; \ 652 case Py_LT: if ((val1) < (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE; \ 653 case Py_GT: if ((val1) > (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE; \ 654 case Py_LE: if ((val1) <= (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE; \ 655 case Py_GE: if ((val1) >= (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE; \ 656 default: \ 657 Py_UNREACHABLE(); \ 658 } \ 659 } while (0) 660 661 662 /* 663 More conventions 664 ================ 665 666 Argument Checking 667 ----------------- 668 669 Functions that take objects as arguments normally don't check for nil 670 arguments, but they do check the type of the argument, and return an 671 error if the function doesn't apply to the type. 672 673 Failure Modes 674 ------------- 675 676 Functions may fail for a variety of reasons, including running out of 677 memory. This is communicated to the caller in two ways: an error string 678 is set (see errors.h), and the function result differs: functions that 679 normally return a pointer return NULL for failure, functions returning 680 an integer return -1 (which could be a legal return value too!), and 681 other functions return 0 for success and -1 for failure. 682 Callers should always check for errors before using the result. If 683 an error was set, the caller must either explicitly clear it, or pass 684 the error on to its caller. 685 686 Reference Counts 687 ---------------- 688 689 It takes a while to get used to the proper usage of reference counts. 690 691 Functions that create an object set the reference count to 1; such new 692 objects must be stored somewhere or destroyed again with Py_DECREF(). 693 Some functions that 'store' objects, such as PyTuple_SetItem() and 694 PyList_SetItem(), 695 don't increment the reference count of the object, since the most 696 frequent use is to store a fresh object. Functions that 'retrieve' 697 objects, such as PyTuple_GetItem() and PyDict_GetItemString(), also 698 don't increment 699 the reference count, since most frequently the object is only looked at 700 quickly. Thus, to retrieve an object and store it again, the caller 701 must call Py_INCREF() explicitly. 702 703 NOTE: functions that 'consume' a reference count, like 704 PyList_SetItem(), consume the reference even if the object wasn't 705 successfully stored, to simplify error handling. 706 707 It seems attractive to make other functions that take an object as 708 argument consume a reference count; however, this may quickly get 709 confusing (even the current practice is already confusing). Consider 710 it carefully, it may save lots of calls to Py_INCREF() and Py_DECREF() at 711 times. 712 */ 713 714 #ifndef Py_LIMITED_API 715 # define Py_CPYTHON_OBJECT_H 716 # include "cpython/object.h" 717 # undef Py_CPYTHON_OBJECT_H 718 #endif 719 720 721 static inline int 722 PyType_HasFeature(PyTypeObject *type, unsigned long feature) 723 { 724 unsigned long flags; 725 #ifdef Py_LIMITED_API 726 // PyTypeObject is opaque in the limited C API 727 flags = PyType_GetFlags(type); 728 #else 729 flags = type->tp_flags; 730 #endif 731 return ((flags & feature) != 0); 732 } 733 734 #define PyType_FastSubclass(type, flag) PyType_HasFeature(type, flag) 735 736 static inline int _PyType_Check(PyObject *op) { 737 return PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_TYPE_SUBCLASS); 738 } 739 #define PyType_Check(op) _PyType_Check(_PyObject_CAST(op)) 740 741 static inline int _PyType_CheckExact(PyObject *op) { 742 return Py_IS_TYPE(op, &PyType_Type); 743 } 744 #define PyType_CheckExact(op) _PyType_CheckExact(_PyObject_CAST(op)) 745 746 #ifdef __cplusplus 747 } 748 #endif 749 #endif /* !Py_OBJECT_H */
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