LCOV - code coverage report
Current view: | top level - Include - object.h (source / functions) |  |  | Hit | Total | Coverage
Test: | CPython 3.12 LCOV report [commit 5e6661bce9] |  | Lines: | 48 | 49 | 98.0 %
Date: | 2023-03-20 08:15:36 |  | Functions: | 17 | 17 | 100.0 %
|  |  | Branches: | 10 | 10 | 100.0 %

               Branch data     Line data    Source code
           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                 :            : #define PyObject_HEAD_INIT(type)        \
          82                 :            :     { _PyObject_EXTRA_INIT              \
          83                 :            :     1, (type) },
          84                 :            :
          85                 :            : #define PyVarObject_HEAD_INIT(type, size)       \
          86                 :            :     { PyObject_HEAD_INIT(type) (size) },
          87                 :            :
          88                 :            : /* PyObject_VAR_HEAD defines the initial segment of all variable-size
          89                 :            :  * container objects.  These end with a declaration of an array with 1
          90                 :            :  * element, but enough space is malloc'ed so that the array actually
          91                 :            :  * has room for ob_size elements.  Note that ob_size is an element count,
          92                 :            :  * not necessarily a byte count.
          93                 :            :  */
          94                 :            : #define PyObject_VAR_HEAD      PyVarObject ob_base;
          95                 :            : #define Py_INVALID_SIZE (Py_ssize_t)-1
          96                 :            :
          97                 :            : /* Nothing is actually declared to be a PyObject, but every pointer to
          98                 :            :  * a Python object can be cast to a PyObject*.  This is inheritance built
          99                 :            :  * by hand.  Similarly every pointer to a variable-size Python object can,
         100                 :            :  * in addition, be cast to PyVarObject*.
         101                 :            :  */
         102                 :            : struct _object {
         103                 :            :     _PyObject_HEAD_EXTRA
         104                 :            :     Py_ssize_t ob_refcnt;
         105                 :            :     PyTypeObject *ob_type;
         106                 :            : };
         107                 :            :
         108                 :            : /* Cast argument to PyObject* type. */
         109                 :            : #define _PyObject_CAST(op) _Py_CAST(PyObject*, (op))
         110                 :            :
         111                 :            : typedef struct {
         112                 :            :     PyObject ob_base;
         113                 :            :     Py_ssize_t ob_size; /* Number of items in variable part */
         114                 :            : } PyVarObject;
         115                 :            :
         116                 :            : /* Cast argument to PyVarObject* type. */
         117                 :            : #define _PyVarObject_CAST(op) _Py_CAST(PyVarObject*, (op))
         118                 :            :
         119                 :            :
         120                 :            : // Test if the 'x' object is the 'y' object, the same as "x is y" in Python.
         121                 :            : PyAPI_FUNC(int) Py_Is(PyObject *x, PyObject *y);
         122                 :            : #define Py_Is(x, y) ((x) == (y))
         123                 :            :
         124                 :            :
         125                 :    8040154 : static inline Py_ssize_t Py_REFCNT(PyObject *ob) {
         126                 :    8040154 :     return ob->ob_refcnt;
         127                 :            : }
         128                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
         129                 :            : #  define Py_REFCNT(ob) Py_REFCNT(_PyObject_CAST(ob))
         130                 :            : #endif
         131                 :            :
         132                 :            :
         133                 :            : // bpo-39573: The Py_SET_TYPE() function must be used to set an object type.
         134                 :  328836979 : static inline PyTypeObject* Py_TYPE(PyObject *ob) {
         135                 :  328836979 :     return ob->ob_type;
         136                 :            : }
         137                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
         138                 :            : #  define Py_TYPE(ob) Py_TYPE(_PyObject_CAST(ob))
         139                 :            : #endif
         140                 :            :
         141                 :            : // bpo-39573: The Py_SET_SIZE() function must be used to set an object size.
         142                 :  112896026 : static inline Py_ssize_t Py_SIZE(PyObject *ob) {
         143                 :  112896026 :     PyVarObject *var_ob = _PyVarObject_CAST(ob);
         144                 :  112896026 :     return var_ob->ob_size;
         145                 :            : }
         146                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
         147                 :            : #  define Py_SIZE(ob) Py_SIZE(_PyObject_CAST(ob))
         148                 :            : #endif
         149                 :            :
         150                 :            :
         151                 :   67649253 : static inline int Py_IS_TYPE(PyObject *ob, PyTypeObject *type) {
         152                 :   67649253 :     return Py_TYPE(ob) == type;
         153                 :            : }
         154                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
         155                 :            : #  define Py_IS_TYPE(ob, type) Py_IS_TYPE(_PyObject_CAST(ob), (type))
         156                 :            : #endif
         157                 :            :
         158                 :            :
         159                 :   31466638 : static inline void Py_SET_REFCNT(PyObject *ob, Py_ssize_t refcnt) {
         160                 :   31466638 :     ob->ob_refcnt = refcnt;
         161                 :   31466638 : }
         162                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
         163                 :            : #  define Py_SET_REFCNT(ob, refcnt) Py_SET_REFCNT(_PyObject_CAST(ob), (refcnt))
         164                 :            : #endif
         165                 :            :
         166                 :            :
         167                 :   28346564 : static inline void Py_SET_TYPE(PyObject *ob, PyTypeObject *type) {
         168                 :   28346564 :     ob->ob_type = type;
         169                 :   28346564 : }
         170                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
         171                 :            : #  define Py_SET_TYPE(ob, type) Py_SET_TYPE(_PyObject_CAST(ob), type)
         172                 :            : #endif
         173                 :            :
         174                 :            :
         175                 :   16923540 : static inline void Py_SET_SIZE(PyVarObject *ob, Py_ssize_t size) {
         176                 :   16923540 :     ob->ob_size = size;
         177                 :   16923540 : }
         178                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
         179                 :            : #  define Py_SET_SIZE(ob, size) Py_SET_SIZE(_PyVarObject_CAST(ob), (size))
         180                 :            : #endif
         181                 :            :
         182                 :            :
         183                 :            : /*
         184                 :            : Type objects contain a string containing the type name (to help somewhat
         185                 :            : in debugging), the allocation parameters (see PyObject_New() and
         186                 :            : PyObject_NewVar()),
         187                 :            : and methods for accessing objects of the type.  Methods are optional, a
         188                 :            : nil pointer meaning that particular kind of access is not available for
         189                 :            : this type.  The Py_DECREF() macro uses the tp_dealloc method without
         190                 :            : checking for a nil pointer; it should always be implemented except if
         191                 :            : the implementation can guarantee that the reference count will never
         192                 :            : reach zero (e.g., for statically allocated type objects).
         193                 :            :
         194                 :            : NB: the methods for certain type groups are now contained in separate
         195                 :            : method blocks.
         196                 :            : */
         197                 :            :
         198                 :            : typedef PyObject * (*unaryfunc)(PyObject *);
         199                 :            : typedef PyObject * (*binaryfunc)(PyObject *, PyObject *);
         200                 :            : typedef PyObject * (*ternaryfunc)(PyObject *, PyObject *, PyObject *);
         201                 :            : typedef int (*inquiry)(PyObject *);
         202                 :            : typedef Py_ssize_t (*lenfunc)(PyObject *);
         203                 :            : typedef PyObject *(*ssizeargfunc)(PyObject *, Py_ssize_t);
         204                 :            : typedef PyObject *(*ssizessizeargfunc)(PyObject *, Py_ssize_t, Py_ssize_t);
         205                 :            : typedef int(*ssizeobjargproc)(PyObject *, Py_ssize_t, PyObject *);
         206                 :            : typedef int(*ssizessizeobjargproc)(PyObject *, Py_ssize_t, Py_ssize_t, PyObject *);
         207                 :            : typedef int(*objobjargproc)(PyObject *, PyObject *, PyObject *);
         208                 :            :
         209                 :            : typedef int (*objobjproc)(PyObject *, PyObject *);
         210                 :            : typedef int (*visitproc)(PyObject *, void *);
         211                 :            : typedef int (*traverseproc)(PyObject *, visitproc, void *);
         212                 :            :
         213                 :            :
         214                 :            : typedef void (*freefunc)(void *);
         215                 :            : typedef void (*destructor)(PyObject *);
         216                 :            : typedef PyObject *(*getattrfunc)(PyObject *, char *);
         217                 :            : typedef PyObject *(*getattrofunc)(PyObject *, PyObject *);
         218                 :            : typedef int (*setattrfunc)(PyObject *, char *, PyObject *);
         219                 :            : typedef int (*setattrofunc)(PyObject *, PyObject *, PyObject *);
         220                 :            : typedef PyObject *(*reprfunc)(PyObject *);
         221                 :            : typedef Py_hash_t (*hashfunc)(PyObject *);
         222                 :            : typedef PyObject *(*richcmpfunc) (PyObject *, PyObject *, int);
         223                 :            : typedef PyObject *(*getiterfunc) (PyObject *);
         224                 :            : typedef PyObject *(*iternextfunc) (PyObject *);
         225                 :            : typedef PyObject *(*descrgetfunc) (PyObject *, PyObject *, PyObject *);
         226                 :            : typedef int (*descrsetfunc) (PyObject *, PyObject *, PyObject *);
         227                 :            : typedef int (*initproc)(PyObject *, PyObject *, PyObject *);
         228                 :            : typedef PyObject *(*newfunc)(PyTypeObject *, PyObject *, PyObject *);
         229                 :            : typedef PyObject *(*allocfunc)(PyTypeObject *, Py_ssize_t);
         230                 :            :
         231                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030c0000 // 3.12
         232                 :            : typedef PyObject *(*vectorcallfunc)(PyObject *callable, PyObject *const *args,
         233                 :            :                                     size_t nargsf, PyObject *kwnames);
         234                 :            : #endif
         235                 :            :
         236                 :            : typedef struct{
         237                 :            :     int slot;    /* slot id, see below */
         238                 :            :     void *pfunc; /* function pointer */
         239                 :            : } PyType_Slot;
         240                 :            :
         241                 :            : typedef struct{
         242                 :            :     const char* name;
         243                 :            :     int basicsize;
         244                 :            :     int itemsize;
         245                 :            :     unsigned int flags;
         246                 :            :     PyType_Slot *slots; /* terminated by slot==0. */
         247                 :            : } PyType_Spec;
         248                 :            :
         249                 :            : PyAPI_FUNC(PyObject*) PyType_FromSpec(PyType_Spec*);
         250                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03030000
         251                 :            : PyAPI_FUNC(PyObject*) PyType_FromSpecWithBases(PyType_Spec*, PyObject*);
         252                 :            : #endif
         253                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03040000
         254                 :            : PyAPI_FUNC(void*) PyType_GetSlot(PyTypeObject*, int);
         255                 :            : #endif
         256                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03090000
         257                 :            : PyAPI_FUNC(PyObject*) PyType_FromModuleAndSpec(PyObject *, PyType_Spec *, PyObject *);
         258                 :            : PyAPI_FUNC(PyObject *) PyType_GetModule(PyTypeObject *);
         259                 :            : PyAPI_FUNC(void *) PyType_GetModuleState(PyTypeObject *);
         260                 :            : #endif
         261                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030B0000
         262                 :            : PyAPI_FUNC(PyObject *) PyType_GetName(PyTypeObject *);
         263                 :            : PyAPI_FUNC(PyObject *) PyType_GetQualName(PyTypeObject *);
         264                 :            : #endif
         265                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030C0000
         266                 :            : PyAPI_FUNC(PyObject *) PyType_FromMetaclass(PyTypeObject*, PyObject*, PyType_Spec*, PyObject*);
         267                 :            : #endif
         268                 :            :
         269                 :            : /* Generic type check */
         270                 :            : PyAPI_FUNC(int) PyType_IsSubtype(PyTypeObject *, PyTypeObject *);
         271                 :            :
         272                 :    7876598 : static inline int PyObject_TypeCheck(PyObject *ob, PyTypeObject *type) {
         273   [ +  +  +  + ]:    7876598 :     return Py_IS_TYPE(ob, type) || PyType_IsSubtype(Py_TYPE(ob), type);
         274                 :            : }
         275                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
         276                 :            : #  define PyObject_TypeCheck(ob, type) PyObject_TypeCheck(_PyObject_CAST(ob), (type))
         277                 :            : #endif
         278                 :            :
         279                 :            : PyAPI_DATA(PyTypeObject) PyType_Type; /* built-in 'type' */
         280                 :            : PyAPI_DATA(PyTypeObject) PyBaseObject_Type; /* built-in 'object' */
         281                 :            : PyAPI_DATA(PyTypeObject) PySuper_Type; /* built-in 'super' */
         282                 :            :
         283                 :            : PyAPI_FUNC(unsigned long) PyType_GetFlags(PyTypeObject*);
         284                 :            :
         285                 :            : PyAPI_FUNC(int) PyType_Ready(PyTypeObject *);
         286                 :            : PyAPI_FUNC(PyObject *) PyType_GenericAlloc(PyTypeObject *, Py_ssize_t);
         287                 :            : PyAPI_FUNC(PyObject *) PyType_GenericNew(PyTypeObject *,
         288                 :            :                                                PyObject *, PyObject *);
         289                 :            : PyAPI_FUNC(unsigned int) PyType_ClearCache(void);
         290                 :            : PyAPI_FUNC(void) PyType_Modified(PyTypeObject *);
         291                 :            :
         292                 :            : /* Generic operations on objects */
         293                 :            : PyAPI_FUNC(PyObject *) PyObject_Repr(PyObject *);
         294                 :            : PyAPI_FUNC(PyObject *) PyObject_Str(PyObject *);
         295                 :            : PyAPI_FUNC(PyObject *) PyObject_ASCII(PyObject *);
         296                 :            : PyAPI_FUNC(PyObject *) PyObject_Bytes(PyObject *);
         297                 :            : PyAPI_FUNC(PyObject *) PyObject_RichCompare(PyObject *, PyObject *, int);
         298                 :            : PyAPI_FUNC(int) PyObject_RichCompareBool(PyObject *, PyObject *, int);
         299                 :            : PyAPI_FUNC(PyObject *) PyObject_GetAttrString(PyObject *, const char *);
         300                 :            : PyAPI_FUNC(int) PyObject_SetAttrString(PyObject *, const char *, PyObject *);
         301                 :            : PyAPI_FUNC(int) PyObject_HasAttrString(PyObject *, const char *);
         302                 :            : PyAPI_FUNC(PyObject *) PyObject_GetAttr(PyObject *, PyObject *);
         303                 :            : PyAPI_FUNC(int) PyObject_SetAttr(PyObject *, PyObject *, PyObject *);
         304                 :            : PyAPI_FUNC(int) PyObject_HasAttr(PyObject *, PyObject *);
         305                 :            : PyAPI_FUNC(PyObject *) PyObject_SelfIter(PyObject *);
         306                 :            : PyAPI_FUNC(PyObject *) PyObject_GenericGetAttr(PyObject *, PyObject *);
         307                 :            : PyAPI_FUNC(int) PyObject_GenericSetAttr(PyObject *, PyObject *, PyObject *);
         308                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03030000
         309                 :            : PyAPI_FUNC(int) PyObject_GenericSetDict(PyObject *, PyObject *, void *);
         310                 :            : #endif
         311                 :            : PyAPI_FUNC(Py_hash_t) PyObject_Hash(PyObject *);
         312                 :            : PyAPI_FUNC(Py_hash_t) PyObject_HashNotImplemented(PyObject *);
         313                 :            : PyAPI_FUNC(int) PyObject_IsTrue(PyObject *);
         314                 :            : PyAPI_FUNC(int) PyObject_Not(PyObject *);
         315                 :            : PyAPI_FUNC(int) PyCallable_Check(PyObject *);
         316                 :            : PyAPI_FUNC(void) PyObject_ClearWeakRefs(PyObject *);
         317                 :            :
         318                 :            : /* PyObject_Dir(obj) acts like Python builtins.dir(obj), returning a
         319                 :            :    list of strings.  PyObject_Dir(NULL) is like builtins.dir(),
         320                 :            :    returning the names of the current locals.  In this case, if there are
         321                 :            :    no current locals, NULL is returned, and PyErr_Occurred() is false.
         322                 :            : */
         323                 :            : PyAPI_FUNC(PyObject *) PyObject_Dir(PyObject *);
         324                 :            :
         325                 :            : /* Pickle support. */
         326                 :            : #ifndef Py_LIMITED_API
         327                 :            : PyAPI_FUNC(PyObject *) _PyObject_GetState(PyObject *);
         328                 :            : #endif
         329                 :            :
         330                 :            :
         331                 :            : /* Helpers for printing recursive container types */
         332                 :            : PyAPI_FUNC(int) Py_ReprEnter(PyObject *);
         333                 :            : PyAPI_FUNC(void) Py_ReprLeave(PyObject *);
         334                 :            :
         335                 :            : /* Flag bits for printing: */
         336                 :            : #define Py_PRINT_RAW    1       /* No string quotes etc. */
         337                 :            :
         338                 :            : /*
         339                 :            : Type flags (tp_flags)
         340                 :            :
         341                 :            : These flags are used to change expected features and behavior for a
         342                 :            : particular type.
         343                 :            :
         344                 :            : Arbitration of the flag bit positions will need to be coordinated among
         345                 :            : all extension writers who publicly release their extensions (this will
         346                 :            : be fewer than you might expect!).
         347                 :            :
         348                 :            : Most flags were removed as of Python 3.0 to make room for new flags.  (Some
         349                 :            : flags are not for backwards compatibility but to indicate the presence of an
         350                 :            : optional feature; these flags remain of course.)
         351                 :            :
         352                 :            : Type definitions should use Py_TPFLAGS_DEFAULT for their tp_flags value.
         353                 :            :
         354                 :            : Code can use PyType_HasFeature(type_ob, flag_value) to test whether the
         355                 :            : given type object has a specified feature.
         356                 :            : */
         357                 :            :
         358                 :            : #ifndef Py_LIMITED_API
         359                 :            :
         360                 :            : /* Track types initialized using _PyStaticType_InitBuiltin(). */
         361                 :            : #define _Py_TPFLAGS_STATIC_BUILTIN (1 << 1)
         362                 :            :
         363                 :            : /* Placement of weakref pointers are managed by the VM, not by the type.
         364                 :            :  * The VM will automatically set tp_weaklistoffset.
         365                 :            :  */
         366                 :            : #define Py_TPFLAGS_MANAGED_WEAKREF (1 << 3)
         367                 :            :
         368                 :            : /* Placement of dict (and values) pointers are managed by the VM, not by the type.
         369                 :            :  * The VM will automatically set tp_dictoffset.
         370                 :            :  */
         371                 :            : #define Py_TPFLAGS_MANAGED_DICT (1 << 4)
         372                 :            :
         373                 :            : #define Py_TPFLAGS_PREHEADER (Py_TPFLAGS_MANAGED_WEAKREF | Py_TPFLAGS_MANAGED_DICT)
         374                 :            :
         375                 :            : /* Set if instances of the type object are treated as sequences for pattern matching */
         376                 :            : #define Py_TPFLAGS_SEQUENCE (1 << 5)
         377                 :            : /* Set if instances of the type object are treated as mappings for pattern matching */
         378                 :            : #define Py_TPFLAGS_MAPPING (1 << 6)
         379                 :            : #endif
         380                 :            :
         381                 :            : /* Disallow creating instances of the type: set tp_new to NULL and don't create
         382                 :            :  * the "__new__" key in the type dictionary. */
         383                 :            : #define Py_TPFLAGS_DISALLOW_INSTANTIATION (1UL << 7)
         384                 :            :
         385                 :            : /* Set if the type object is immutable: type attributes cannot be set nor deleted */
         386                 :            : #define Py_TPFLAGS_IMMUTABLETYPE (1UL << 8)
         387                 :            :
         388                 :            : /* Set if the type object is dynamically allocated */
         389                 :            : #define Py_TPFLAGS_HEAPTYPE (1UL << 9)
         390                 :            :
         391                 :            : /* Set if the type allows subclassing */
         392                 :            : #define Py_TPFLAGS_BASETYPE (1UL << 10)
         393                 :            :
         394                 :            : /* Set if the type implements the vectorcall protocol (PEP 590) */
         395                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030C0000
         396                 :            : #define Py_TPFLAGS_HAVE_VECTORCALL (1UL << 11)
         397                 :            : #ifndef Py_LIMITED_API
         398                 :            : // Backwards compatibility alias for API that was provisional in Python 3.8
         399                 :            : #define _Py_TPFLAGS_HAVE_VECTORCALL Py_TPFLAGS_HAVE_VECTORCALL
         400                 :            : #endif
         401                 :            : #endif
         402                 :            :
         403                 :            : /* Set if the type is 'ready' -- fully initialized */
         404                 :            : #define Py_TPFLAGS_READY (1UL << 12)
         405                 :            :
         406                 :            : /* Set while the type is being 'readied', to prevent recursive ready calls */
         407                 :            : #define Py_TPFLAGS_READYING (1UL << 13)
         408                 :            :
         409                 :            : /* Objects support garbage collection (see objimpl.h) */
         410                 :            : #define Py_TPFLAGS_HAVE_GC (1UL << 14)
         411                 :            :
         412                 :            : /* These two bits are preserved for Stackless Python, next after this is 17 */
         413                 :            : #ifdef STACKLESS
         414                 :            : #define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION (3UL << 15)
         415                 :            : #else
         416                 :            : #define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION 0
         417                 :            : #endif
         418                 :            :
         419                 :            : /* Objects behave like an unbound method */
         420                 :            : #define Py_TPFLAGS_METHOD_DESCRIPTOR (1UL << 17)
         421                 :            :
         422                 :            : /* Object has up-to-date type attribute cache */
         423                 :            : #define Py_TPFLAGS_VALID_VERSION_TAG  (1UL << 19)
         424                 :            :
         425                 :            : /* Type is abstract and cannot be instantiated */
         426                 :            : #define Py_TPFLAGS_IS_ABSTRACT (1UL << 20)
         427                 :            :
         428                 :            : // This undocumented flag gives certain built-ins their unique pattern-matching
         429                 :            : // behavior, which allows a single positional subpattern to match against the
         430                 :            : // subject itself (rather than a mapped attribute on it):
         431                 :            : #define _Py_TPFLAGS_MATCH_SELF (1UL << 22)
         432                 :            :
         433                 :            : /* These flags are used to determine if a type is a subclass. */
         434                 :            : #define Py_TPFLAGS_LONG_SUBCLASS        (1UL << 24)
         435                 :            : #define Py_TPFLAGS_LIST_SUBCLASS        (1UL << 25)
         436                 :            : #define Py_TPFLAGS_TUPLE_SUBCLASS       (1UL << 26)
         437                 :            : #define Py_TPFLAGS_BYTES_SUBCLASS       (1UL << 27)
         438                 :            : #define Py_TPFLAGS_UNICODE_SUBCLASS     (1UL << 28)
         439                 :            : #define Py_TPFLAGS_DICT_SUBCLASS        (1UL << 29)
         440                 :            : #define Py_TPFLAGS_BASE_EXC_SUBCLASS    (1UL << 30)
         441                 :            : #define Py_TPFLAGS_TYPE_SUBCLASS        (1UL << 31)
         442                 :            :
         443                 :            : #define Py_TPFLAGS_DEFAULT  ( \
         444                 :            :                  Py_TPFLAGS_HAVE_STACKLESS_EXTENSION | \
         445                 :            :                 0)
         446                 :            :
         447                 :            : /* NOTE: Some of the following flags reuse lower bits (removed as part of the
         448                 :            :  * Python 3.0 transition). */
         449                 :            :
         450                 :            : /* The following flags are kept for compatibility; in previous
         451                 :            :  * versions they indicated presence of newer tp_* fields on the
         452                 :            :  * type struct.
         453                 :            :  * Starting with 3.8, binary compatibility of C extensions across
         454                 :            :  * feature releases of Python is not supported anymore (except when
         455                 :            :  * using the stable ABI, in which all classes are created dynamically,
         456                 :            :  * using the interpreter's memory layout.)
         457                 :            :  * Note that older extensions using the stable ABI set these flags,
         458                 :            :  * so the bits must not be repurposed.
         459                 :            :  */
         460                 :            : #define Py_TPFLAGS_HAVE_FINALIZE (1UL << 0)
         461                 :            : #define Py_TPFLAGS_HAVE_VERSION_TAG   (1UL << 18)
         462                 :            :
         463                 :            :
         464                 :            : /*
         465                 :            : The macros Py_INCREF(op) and Py_DECREF(op) are used to increment or decrement
         466                 :            : reference counts.  Py_DECREF calls the object's deallocator function when
         467                 :            : the refcount falls to 0; for
         468                 :            : objects that don't contain references to other objects or heap memory
         469                 :            : this can be the standard function free().  Both macros can be used
         470                 :            : wherever a void expression is allowed.  The argument must not be a
         471                 :            : NULL pointer.  If it may be NULL, use Py_XINCREF/Py_XDECREF instead.
         472                 :            : The macro _Py_NewReference(op) initialize reference counts to 1, and
         473                 :            : in special builds (Py_REF_DEBUG, Py_TRACE_REFS) performs additional
         474                 :            : bookkeeping appropriate to the special build.
         475                 :            :
         476                 :            : We assume that the reference count field can never overflow; this can
         477                 :            : be proven when the size of the field is the same as the pointer size, so
         478                 :            : we ignore the possibility.  Provided a C int is at least 32 bits (which
         479                 :            : is implicitly assumed in many parts of this code), that's enough for
         480                 :            : about 2**31 references to an object.
         481                 :            :
         482                 :            : XXX The following became out of date in Python 2.2, but I'm not sure
         483                 :            : XXX what the full truth is now.  Certainly, heap-allocated type objects
         484                 :            : XXX can and should be deallocated.
         485                 :            : Type objects should never be deallocated; the type pointer in an object
         486                 :            : is not considered to be a reference to the type object, to save
         487                 :            : complications in the deallocation function.  (This is actually a
         488                 :            : decision that's up to the implementer of each new type so if you want,
         489                 :            : you can count such references to the type object.)
         490                 :            : */
         491                 :            :
         492                 :            : #ifdef Py_REF_DEBUG
         493                 :            : #  if defined(Py_LIMITED_API) && Py_LIMITED_API+0 < 0x030A0000
         494                 :            : extern Py_ssize_t _Py_RefTotal;
         495                 :            : #    define _Py_INC_REFTOTAL() _Py_RefTotal++
         496                 :            : #    define _Py_DEC_REFTOTAL() _Py_RefTotal--
         497                 :            : #  elif defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
         498                 :            : extern void _Py_IncRefTotal(void);
         499                 :            : extern void _Py_DecRefTotal(void);
         500                 :            : #    define _Py_INC_REFTOTAL() _Py_IncRefTotal()
         501                 :            : #    define _Py_DEC_REFTOTAL() _Py_DecRefTotal()
         502                 :            : #  elif !defined(Py_LIMITED_API) || Py_LIMITED_API+0 > 0x030C0000
         503                 :            : extern void _Py_IncRefTotal_DO_NOT_USE_THIS(void);
         504                 :            : extern void _Py_DecRefTotal_DO_NOT_USE_THIS(void);
         505                 :            : #    define _Py_INC_REFTOTAL() _Py_IncRefTotal_DO_NOT_USE_THIS()
         506                 :            : #    define _Py_DEC_REFTOTAL() _Py_DecRefTotal_DO_NOT_USE_THIS()
         507                 :            : #  endif
         508                 :            : PyAPI_FUNC(void) _Py_NegativeRefcount(const char *filename, int lineno,
         509                 :            :                                       PyObject *op);
         510                 :            : #endif /* Py_REF_DEBUG */
         511                 :            :
         512                 :            : PyAPI_FUNC(void) _Py_Dealloc(PyObject *);
         513                 :            :
         514                 :            : /*
         515                 :            : These are provided as conveniences to Python runtime embedders, so that
         516                 :            : they can have object code that is not dependent on Python compilation flags.
         517                 :            : */
         518                 :            : PyAPI_FUNC(void) Py_IncRef(PyObject *);
         519                 :            : PyAPI_FUNC(void) Py_DecRef(PyObject *);
         520                 :            :
         521                 :            : // Similar to Py_IncRef() and Py_DecRef() but the argument must be non-NULL.
         522                 :            : // Private functions used by Py_INCREF() and Py_DECREF().
         523                 :            : PyAPI_FUNC(void) _Py_IncRef(PyObject *);
         524                 :            : PyAPI_FUNC(void) _Py_DecRef(PyObject *);
         525                 :            :
         526                 :  161420248 : static inline void Py_INCREF(PyObject *op)
         527                 :            : {
         528                 :            : #if defined(Py_REF_DEBUG) && defined(Py_LIMITED_API) && Py_LIMITED_API+0 >= 0x030A0000
         529                 :            :     // Stable ABI for Python 3.10 built in debug mode.
         530                 :            :     _Py_IncRef(op);
         531                 :            : #else
         532                 :            :     _Py_INCREF_STAT_INC();
         533                 :            :     // Non-limited C API and limited C API for Python 3.9 and older access
         534                 :            :     // directly PyObject.ob_refcnt.
         535                 :            : #ifdef Py_REF_DEBUG
         536                 :            :     _Py_INC_REFTOTAL();
         537                 :            : #endif  // Py_REF_DEBUG
         538                 :  161420248 :     op->ob_refcnt++;
         539                 :            : #endif
         540                 :  161420248 : }
         541                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
         542                 :            : #  define Py_INCREF(op) Py_INCREF(_PyObject_CAST(op))
         543                 :            : #endif
         544                 :            :
         545                 :            : #if defined(Py_REF_DEBUG) && defined(Py_LIMITED_API) && Py_LIMITED_API+0 >= 0x030A0000
         546                 :            : // Stable ABI for limited C API version 3.10 of Python debug build
         547                 :            : static inline void Py_DECREF(PyObject *op) {
         548                 :            :     _Py_DecRef(op);
         549                 :            : }
         550                 :            : #define Py_DECREF(op) Py_DECREF(_PyObject_CAST(op))
         551                 :            :
         552                 :            : #elif defined(Py_REF_DEBUG)
         553                 :            : static inline void Py_DECREF(const char *filename, int lineno, PyObject *op)
         554                 :            : {
         555                 :            :     _Py_DECREF_STAT_INC();
         556                 :            :     _Py_DEC_REFTOTAL();
         557                 :            :     if (--op->ob_refcnt != 0) {
         558                 :            :         if (op->ob_refcnt < 0) {
         559                 :            :             _Py_NegativeRefcount(filename, lineno, op);
         560                 :            :         }
         561                 :            :     }
         562                 :            :     else {
         563                 :            :         _Py_Dealloc(op);
         564                 :            :     }
         565                 :            : }
         566                 :            : #define Py_DECREF(op) Py_DECREF(__FILE__, __LINE__, _PyObject_CAST(op))
         567                 :            :
         568                 :            : #else
         569                 :  112122299 : static inline void Py_DECREF(PyObject *op)
         570                 :            : {
         571                 :            :     _Py_DECREF_STAT_INC();
         572                 :            :     // Non-limited C API and limited C API for Python 3.9 and older access
         573                 :            :     // directly PyObject.ob_refcnt.
         574         [ +  + ]:  112122299 :     if (--op->ob_refcnt == 0) {
         575                 :   18024377 :         _Py_Dealloc(op);
         576                 :            :     }
         577                 :  112122299 : }
         578                 :            : #define Py_DECREF(op) Py_DECREF(_PyObject_CAST(op))
         579                 :            : #endif
         580                 :            :
         581                 :            : #undef _Py_INC_REFTOTAL
         582                 :            : #undef _Py_DEC_REFTOTAL
         583                 :            :
         584                 :            :
         585                 :            : /* Safely decref `op` and set `op` to NULL, especially useful in tp_clear
         586                 :            :  * and tp_dealloc implementations.
         587                 :            :  *
         588                 :            :  * Note that "the obvious" code can be deadly:
         589                 :            :  *
         590                 :            :  *     Py_XDECREF(op);
         591                 :            :  *     op = NULL;
         592                 :            :  *
         593                 :            :  * Typically, `op` is something like self->containee, and `self` is done
         594                 :            :  * using its `containee` member.  In the code sequence above, suppose
         595                 :            :  * `containee` is non-NULL with a refcount of 1.  Its refcount falls to
         596                 :            :  * 0 on the first line, which can trigger an arbitrary amount of code,
         597                 :            :  * possibly including finalizers (like __del__ methods or weakref callbacks)
         598                 :            :  * coded in Python, which in turn can release the GIL and allow other threads
         599                 :            :  * to run, etc.  Such code may even invoke methods of `self` again, or cause
         600                 :            :  * cyclic gc to trigger, but-- oops! --self->containee still points to the
         601                 :            :  * object being torn down, and it may be in an insane state while being torn
         602                 :            :  * down.  This has in fact been a rich historic source of miserable (rare &
         603                 :            :  * hard-to-diagnose) segfaulting (and other) bugs.
         604                 :            :  *
         605                 :            :  * The safe way is:
         606                 :            :  *
         607                 :            :  *      Py_CLEAR(op);
         608                 :            :  *
         609                 :            :  * That arranges to set `op` to NULL _before_ decref'ing, so that any code
         610                 :            :  * triggered as a side-effect of `op` getting torn down no longer believes
         611                 :            :  * `op` points to a valid object.
         612                 :            :  *
         613                 :            :  * There are cases where it's safe to use the naive code, but they're brittle.
         614                 :            :  * For example, if `op` points to a Python integer, you know that destroying
         615                 :            :  * one of those can't cause problems -- but in part that relies on that
         616                 :            :  * Python integers aren't currently weakly referencable.  Best practice is
         617                 :            :  * to use Py_CLEAR() even if you can't think of a reason for why you need to.
         618                 :            :  *
         619                 :            :  * gh-98724: Use a temporary variable to only evaluate the macro argument once,
         620                 :            :  * to avoid the duplication of side effects if the argument has side effects.
         621                 :            :  *
         622                 :            :  * gh-99701: If the PyObject* type is used with casting arguments to PyObject*,
         623                 :            :  * the code can be miscompiled with strict aliasing because of type punning.
         624                 :            :  * With strict aliasing, a compiler considers that two pointers of different
         625                 :            :  * types cannot read or write the same memory which enables optimization
         626                 :            :  * opportunities.
         627                 :            :  *
         628                 :            :  * If available, use _Py_TYPEOF() to use the 'op' type for temporary variables,
         629                 :            :  * and so avoid type punning. Otherwise, use memcpy() which causes type erasure
         630                 :            :  * and so prevents the compiler to reuse an old cached 'op' value after
         631                 :            :  * Py_CLEAR().
         632                 :            :  */
         633                 :            : #ifdef _Py_TYPEOF
         634                 :            : #define Py_CLEAR(op) \
         635                 :            :     do { \
         636                 :            :         _Py_TYPEOF(op)* _tmp_op_ptr = &(op); \
         637                 :            :         _Py_TYPEOF(op) _tmp_old_op = (*_tmp_op_ptr); \
         638                 :            :         if (_tmp_old_op != NULL) { \
         639                 :            :             *_tmp_op_ptr = _Py_NULL; \
         640                 :            :             Py_DECREF(_tmp_old_op); \
         641                 :            :         } \
         642                 :            :     } while (0)
         643                 :            : #else
         644                 :            : #define Py_CLEAR(op) \
         645                 :            :     do { \
         646                 :            :         PyObject **_tmp_op_ptr = _Py_CAST(PyObject**, &(op)); \
         647                 :            :         PyObject *_tmp_old_op = (*_tmp_op_ptr); \
         648                 :            :         if (_tmp_old_op != NULL) { \
         649                 :            :             PyObject *_null_ptr = _Py_NULL; \
         650                 :            :             memcpy(_tmp_op_ptr, &_null_ptr, sizeof(PyObject*)); \
         651                 :            :             Py_DECREF(_tmp_old_op); \
         652                 :            :         } \
         653                 :            :     } while (0)
         654                 :            : #endif
         655                 :            :
         656                 :            :
         657                 :            : /* Function to use in case the object pointer can be NULL: */
         658                 :    7162978 : static inline void Py_XINCREF(PyObject *op)
         659                 :            : {
         660         [ +  + ]:    7162978 :     if (op != _Py_NULL) {
         661                 :    2901381 :         Py_INCREF(op);
         662                 :            :     }
         663                 :    7162978 : }
         664                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
         665                 :            : #  define Py_XINCREF(op) Py_XINCREF(_PyObject_CAST(op))
         666                 :            : #endif
         667                 :            :
         668                 :   72166708 : static inline void Py_XDECREF(PyObject *op)
         669                 :            : {
         670         [ +  + ]:   72166708 :     if (op != _Py_NULL) {
         671                 :   49898426 :         Py_DECREF(op);
         672                 :            :     }
         673                 :   72166708 : }
         674                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
         675                 :            : #  define Py_XDECREF(op) Py_XDECREF(_PyObject_CAST(op))
         676                 :            : #endif
         677                 :            :
         678                 :            : // Create a new strong reference to an object:
         679                 :            : // increment the reference count of the object and return the object.
         680                 :            : PyAPI_FUNC(PyObject*) Py_NewRef(PyObject *obj);
         681                 :            :
         682                 :            : // Similar to Py_NewRef(), but the object can be NULL.
         683                 :            : PyAPI_FUNC(PyObject*) Py_XNewRef(PyObject *obj);
         684                 :            :
         685                 :   68133682 : static inline PyObject* _Py_NewRef(PyObject *obj)
         686                 :            : {
         687                 :   68133682 :     Py_INCREF(obj);
         688                 :   68133682 :     return obj;
         689                 :            : }
         690                 :            :
         691                 :    5696057 : static inline PyObject* _Py_XNewRef(PyObject *obj)
         692                 :            : {
         693                 :    5696057 :     Py_XINCREF(obj);
         694                 :    5696057 :     return obj;
         695                 :            : }
         696                 :            :
         697                 :            : // Py_NewRef() and Py_XNewRef() are exported as functions for the stable ABI.
         698                 :            : // Names overridden with macros by static inline functions for best
         699                 :            : // performances.
         700                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
         701                 :            : #  define Py_NewRef(obj) _Py_NewRef(_PyObject_CAST(obj))
         702                 :            : #  define Py_XNewRef(obj) _Py_XNewRef(_PyObject_CAST(obj))
         703                 :            : #else
         704                 :            : #  define Py_NewRef(obj) _Py_NewRef(obj)
         705                 :            : #  define Py_XNewRef(obj) _Py_XNewRef(obj)
         706                 :            : #endif
         707                 :            :
         708                 :            :
         709                 :            : /*
         710                 :            : _Py_NoneStruct is an object of undefined type which can be used in contexts
         711                 :            : where NULL (nil) is not suitable (since NULL often means 'error').
         712                 :            :
         713                 :            : Don't forget to apply Py_INCREF() when returning this value!!!
         714                 :            : */
         715                 :            : PyAPI_DATA(PyObject) _Py_NoneStruct; /* Don't use this directly */
         716                 :            : #define Py_None (&_Py_NoneStruct)
         717                 :            :
         718                 :            : // Test if an object is the None singleton, the same as "x is None" in Python.
         719                 :            : PyAPI_FUNC(int) Py_IsNone(PyObject *x);
         720                 :            : #define Py_IsNone(x) Py_Is((x), Py_None)
         721                 :            :
         722                 :            : /* Macro for returning Py_None from a function */
         723                 :            : #define Py_RETURN_NONE return Py_NewRef(Py_None)
         724                 :            :
         725                 :            : /*
         726                 :            : Py_NotImplemented is a singleton used to signal that an operation is
         727                 :            : not implemented for a given type combination.
         728                 :            : */
         729                 :            : PyAPI_DATA(PyObject) _Py_NotImplementedStruct; /* Don't use this directly */
         730                 :            : #define Py_NotImplemented (&_Py_NotImplementedStruct)
         731                 :            :
         732                 :            : /* Macro for returning Py_NotImplemented from a function */
         733                 :            : #define Py_RETURN_NOTIMPLEMENTED return Py_NewRef(Py_NotImplemented)
         734                 :            :
         735                 :            : /* Rich comparison opcodes */
         736                 :            : #define Py_LT 0
         737                 :            : #define Py_LE 1
         738                 :            : #define Py_EQ 2
         739                 :            : #define Py_NE 3
         740                 :            : #define Py_GT 4
         741                 :            : #define Py_GE 5
         742                 :            :
         743                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030A0000
         744                 :            : /* Result of calling PyIter_Send */
         745                 :            : typedef enum {
         746                 :            :     PYGEN_RETURN = 0,
         747                 :            :     PYGEN_ERROR = -1,
         748                 :            :     PYGEN_NEXT = 1,
         749                 :            : } PySendResult;
         750                 :            : #endif
         751                 :            :
         752                 :            : /*
         753                 :            :  * Macro for implementing rich comparisons
         754                 :            :  *
         755                 :            :  * Needs to be a macro because any C-comparable type can be used.
         756                 :            :  */
         757                 :            : #define Py_RETURN_RICHCOMPARE(val1, val2, op)                               \
         758                 :            :     do {                                                                    \
         759                 :            :         switch (op) {                                                       \
         760                 :            :         case Py_EQ: if ((val1) == (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE;  \
         761                 :            :         case Py_NE: if ((val1) != (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE;  \
         762                 :            :         case Py_LT: if ((val1) < (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE;   \
         763                 :            :         case Py_GT: if ((val1) > (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE;   \
         764                 :            :         case Py_LE: if ((val1) <= (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE;  \
         765                 :            :         case Py_GE: if ((val1) >= (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE;  \
         766                 :            :         default:                                                            \
         767                 :            :             Py_UNREACHABLE();                                               \
         768                 :            :         }                                                                   \
         769                 :            :     } while (0)
         770                 :            :
         771                 :            :
         772                 :            : /*
         773                 :            : More conventions
         774                 :            : ================
         775                 :            :
         776                 :            : Argument Checking
         777                 :            : -----------------
         778                 :            :
         779                 :            : Functions that take objects as arguments normally don't check for nil
         780                 :            : arguments, but they do check the type of the argument, and return an
         781                 :            : error if the function doesn't apply to the type.
         782                 :            :
         783                 :            : Failure Modes
         784                 :            : -------------
         785                 :            :
         786                 :            : Functions may fail for a variety of reasons, including running out of
         787                 :            : memory.  This is communicated to the caller in two ways: an error string
         788                 :            : is set (see errors.h), and the function result differs: functions that
         789                 :            : normally return a pointer return NULL for failure, functions returning
         790                 :            : an integer return -1 (which could be a legal return value too!), and
         791                 :            : other functions return 0 for success and -1 for failure.
         792                 :            : Callers should always check for errors before using the result.  If
         793                 :            : an error was set, the caller must either explicitly clear it, or pass
         794                 :            : the error on to its caller.
         795                 :            :
         796                 :            : Reference Counts
         797                 :            : ----------------
         798                 :            :
         799                 :            : It takes a while to get used to the proper usage of reference counts.
         800                 :            :
         801                 :            : Functions that create an object set the reference count to 1; such new
         802                 :            : objects must be stored somewhere or destroyed again with Py_DECREF().
         803                 :            : Some functions that 'store' objects, such as PyTuple_SetItem() and
         804                 :            : PyList_SetItem(),
         805                 :            : don't increment the reference count of the object, since the most
         806                 :            : frequent use is to store a fresh object.  Functions that 'retrieve'
         807                 :            : objects, such as PyTuple_GetItem() and PyDict_GetItemString(), also
         808                 :            : don't increment
         809                 :            : the reference count, since most frequently the object is only looked at
         810                 :            : quickly.  Thus, to retrieve an object and store it again, the caller
         811                 :            : must call Py_INCREF() explicitly.
         812                 :            :
         813                 :            : NOTE: functions that 'consume' a reference count, like
         814                 :            : PyList_SetItem(), consume the reference even if the object wasn't
         815                 :            : successfully stored, to simplify error handling.
         816                 :            :
         817                 :            : It seems attractive to make other functions that take an object as
         818                 :            : argument consume a reference count; however, this may quickly get
         819                 :            : confusing (even the current practice is already confusing).  Consider
         820                 :            : it carefully, it may save lots of calls to Py_INCREF() and Py_DECREF() at
         821                 :            : times.
         822                 :            : */
         823                 :            :
         824                 :            : #ifndef Py_LIMITED_API
         825                 :            : #  define Py_CPYTHON_OBJECT_H
         826                 :            : #  include "cpython/object.h"
         827                 :            : #  undef Py_CPYTHON_OBJECT_H
         828                 :            : #endif
         829                 :            :
         830                 :            :
         831                 :            : static inline int
         832                 :   92253693 : PyType_HasFeature(PyTypeObject *type, unsigned long feature)
         833                 :            : {
         834                 :            :     unsigned long flags;
         835                 :            : #ifdef Py_LIMITED_API
         836                 :            :     // PyTypeObject is opaque in the limited C API
         837                 :          0 :     flags = PyType_GetFlags(type);
         838                 :            : #else
         839                 :   92253693 :     flags = type->tp_flags;
         840                 :            : #endif
         841                 :   92253693 :     return ((flags & feature) != 0);
         842                 :            : }
         843                 :            :
         844                 :            : #define PyType_FastSubclass(type, flag) PyType_HasFeature((type), (flag))
         845                 :            :
         846                 :    4180654 : static inline int PyType_Check(PyObject *op) {
         847                 :    4180654 :     return PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_TYPE_SUBCLASS);
         848                 :            : }
         849                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
         850                 :            : #  define PyType_Check(op) PyType_Check(_PyObject_CAST(op))
         851                 :            : #endif
         852                 :            :
         853                 :            : #define _PyType_CAST(op) \
         854                 :            :     (assert(PyType_Check(op)), _Py_CAST(PyTypeObject*, (op)))
         855                 :            :
         856                 :     152457 : static inline int PyType_CheckExact(PyObject *op) {
         857                 :     152457 :     return Py_IS_TYPE(op, &PyType_Type);
         858                 :            : }
         859                 :            : #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030b0000
         860                 :            : #  define PyType_CheckExact(op) PyType_CheckExact(_PyObject_CAST(op))
         861                 :            : #endif
         862                 :            :
         863                 :            : #ifdef __cplusplus
         864                 :            : }
         865                 :            : #endif
         866                 :            : #endif   // !Py_OBJECT_H

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