Buckets:
| extern "C" { | |
| /* Object and type object interface */ | |
| /* | |
| Objects are structures allocated on the heap. Special rules apply to | |
| the use of objects to ensure they are properly garbage-collected. | |
| Objects are never allocated statically or on the stack; they must be | |
| accessed through special macros and functions only. (Type objects are | |
| exceptions to the first rule; the standard types are represented by | |
| statically initialized type objects, although work on type/class unification | |
| for Python 2.2 made it possible to have heap-allocated type objects too). | |
| An object has a 'reference count' that is increased or decreased when a | |
| pointer to the object is copied or deleted; when the reference count | |
| reaches zero there are no references to the object left and it can be | |
| removed from the heap. | |
| An object has a 'type' that determines what it represents and what kind | |
| of data it contains. An object's type is fixed when it is created. | |
| Types themselves are represented as objects; an object contains a | |
| pointer to the corresponding type object. The type itself has a type | |
| pointer pointing to the object representing the type 'type', which | |
| contains a pointer to itself!. | |
| Objects do not float around in memory; once allocated an object keeps | |
| the same size and address. Objects that must hold variable-size data | |
| can contain pointers to variable-size parts of the object. Not all | |
| objects of the same type have the same size; but the size cannot change | |
| after allocation. (These restrictions are made so a reference to an | |
| object can be simply a pointer -- moving an object would require | |
| updating all the pointers, and changing an object's size would require | |
| moving it if there was another object right next to it.) | |
| Objects are always accessed through pointers of the type 'PyObject *'. | |
| The type 'PyObject' is a structure that only contains the reference count | |
| and the type pointer. The actual memory allocated for an object | |
| contains other data that can only be accessed after casting the pointer | |
| to a pointer to a longer structure type. This longer type must start | |
| with the reference count and type fields; the macro PyObject_HEAD should be | |
| used for this (to accommodate for future changes). The implementation | |
| of a particular object type can cast the object pointer to the proper | |
| type and back. | |
| A standard interface exists for objects that contain an array of items | |
| whose size is determined when the object is allocated. | |
| */ | |
| /* Py_DEBUG implies Py_REF_DEBUG. */ | |
| /* PyObject_HEAD defines the initial segment of every PyObject. */ | |
| /* | |
| Immortalization: | |
| The following indicates the immortalization strategy depending on the amount | |
| of available bits in the reference count field. All strategies are backwards | |
| compatible but the specific reference count value or immortalization check | |
| might change depending on the specializations for the underlying system. | |
| Proper deallocation of immortal instances requires distinguishing between | |
| statically allocated immortal instances vs those promoted by the runtime to be | |
| immortal. The latter should be the only instances that require | |
| cleanup during runtime finalization. | |
| */ | |
| /* | |
| In 64+ bit systems, an object will be marked as immortal by setting all of the | |
| lower 32 bits of the reference count field, which is equal to: 0xFFFFFFFF | |
| Using the lower 32 bits makes the value backwards compatible by allowing | |
| C-Extensions without the updated checks in Py_INCREF and Py_DECREF to safely | |
| increase and decrease the objects reference count. The object would lose its | |
| immortality, but the execution would still be correct. | |
| Reference count increases will use saturated arithmetic, taking advantage of | |
| having all the lower 32 bits set, which will avoid the reference count to go | |
| beyond the refcount limit. Immortality checks for reference count decreases will | |
| be done by checking the bit sign flag in the lower 32 bits. | |
| */ | |
| /* | |
| In 32 bit systems, an object will be marked as immortal by setting all of the | |
| lower 30 bits of the reference count field, which is equal to: 0x3FFFFFFF | |
| Using the lower 30 bits makes the value backwards compatible by allowing | |
| C-Extensions without the updated checks in Py_INCREF and Py_DECREF to safely | |
| increase and decrease the objects reference count. The object would lose its | |
| immortality, but the execution would still be correct. | |
| Reference count increases and decreases will first go through an immortality | |
| check by comparing the reference count field to the immortality reference count. | |
| */ | |
| // Py_GIL_DISABLED builds indicate immortal objects using `ob_ref_local`, which is | |
| // always 32-bits. | |
| // Kept for backward compatibility. It was needed by Py_TRACE_REFS build. | |
| /* Make all uses of PyObject_HEAD_INIT immortal. | |
| * | |
| * Statically allocated objects might be shared between | |
| * interpreters, so must be marked as immortal. | |
| */ | |
| /* PyObject_VAR_HEAD defines the initial segment of all variable-size | |
| * container objects. These end with a declaration of an array with 1 | |
| * element, but enough space is malloc'ed so that the array actually | |
| * has room for ob_size elements. Note that ob_size is an element count, | |
| * not necessarily a byte count. | |
| */ | |
| /* Nothing is actually declared to be a PyObject, but every pointer to | |
| * a Python object can be cast to a PyObject*. This is inheritance built | |
| * by hand. Similarly every pointer to a variable-size Python object can, | |
| * in addition, be cast to PyVarObject*. | |
| */ | |
| struct _object { | |
| // On C99 and older, anonymous union is a GCC and clang extension | |
| __extension__ | |
| // Ignore MSC warning C4201: "nonstandard extension used: | |
| // nameless struct/union" | |
| __pragma(warning(push)) | |
| __pragma(warning(disable: 4201)) | |
| union { | |
| Py_ssize_t ob_refcnt; | |
| PY_UINT32_T ob_refcnt_split[2]; | |
| }; | |
| __pragma(warning(pop)) | |
| PyTypeObject *ob_type; | |
| }; | |
| // Objects that are not owned by any thread use a thread id (tid) of zero. | |
| // This includes both immortal objects and objects whose reference count | |
| // fields have been merged. | |
| // The shared reference count uses the two least-significant bits to store | |
| // flags. The remaining bits are used to store the reference count. | |
| // The shared flags are initialized to zero. | |
| // Create a shared field from a refcnt and desired flags | |
| struct _object { | |
| // ob_tid stores the thread id (or zero). It is also used by the GC and the | |
| // trashcan mechanism as a linked list pointer and by the GC to store the | |
| // computed "gc_refs" refcount. | |
| uintptr_t ob_tid; | |
| uint16_t _padding; | |
| PyMutex ob_mutex; // per-object lock | |
| uint8_t ob_gc_bits; // gc-related state | |
| uint32_t ob_ref_local; // local reference count | |
| Py_ssize_t ob_ref_shared; // shared (atomic) reference count | |
| PyTypeObject *ob_type; | |
| }; | |
| /* Cast argument to PyObject* type. */ | |
| typedef struct { | |
| PyObject ob_base; | |
| Py_ssize_t ob_size; /* Number of items in variable part */ | |
| } PyVarObject; | |
| /* Cast argument to PyVarObject* type. */ | |
| // Test if the 'x' object is the 'y' object, the same as "x is y" in Python. | |
| PyAPI_FUNC(int) Py_Is(PyObject *x, PyObject *y); | |
| PyAPI_FUNC(uintptr_t) _Py_GetThreadLocal_Addr(void); | |
| static inline uintptr_t | |
| _Py_ThreadId(void) | |
| { | |
| uintptr_t tid; | |
| tid = __readgsqword(48); | |
| tid = __readfsdword(24); | |
| tid = __getReg(18); | |
| tid = __readgsqword(48); | |
| tid = __readfsdword(24); | |
| tid = __getReg(18); | |
| __asm__("movl %%gs:0, %0" : "=r" (tid)); // 32-bit always uses GS | |
| __asm__("movq %%gs:0, %0" : "=r" (tid)); // x86_64 macOSX uses GS | |
| __asm__("movq %%fs:0, %0" : "=r" (tid)); // x86_64 Linux, BSD uses FS | |
| __asm__ ("mrc p15, 0, %0, c13, c0, 3\nbic %0, %0, #3" : "=r" (tid)); | |
| __asm__ ("mrs %0, tpidrro_el0" : "=r" (tid)); | |
| __asm__ ("mrs %0, tpidr_el0" : "=r" (tid)); | |
| tid = (uintptr_t)__builtin_thread_pointer(); | |
| // r13 is reserved for use as system thread ID by the Power 64-bit ABI. | |
| register uintptr_t tp __asm__ ("r13"); | |
| __asm__("" : "=r" (tp)); | |
| tid = tp; | |
| tid = (uintptr_t)__builtin_thread_pointer(); | |
| // r2 is reserved for use as system thread ID by the Power 32-bit ABI. | |
| register uintptr_t tp __asm__ ("r2"); | |
| __asm__ ("" : "=r" (tp)); | |
| tid = tp; | |
| // Both GCC and Clang have supported __builtin_thread_pointer | |
| // for s390 from long time ago. | |
| tid = (uintptr_t)__builtin_thread_pointer(); | |
| tid = (uintptr_t)__builtin_thread_pointer(); | |
| // tp is Thread Pointer provided by the RISC-V ABI. | |
| __asm__ ("mv %0, tp" : "=r" (tid)); | |
| // Fallback to a portable implementation if we do not have a faster | |
| // platform-specific implementation. | |
| tid = _Py_GetThreadLocal_Addr(); | |
| return tid; | |
| } | |
| static inline Py_ALWAYS_INLINE int | |
| _Py_IsOwnedByCurrentThread(PyObject *ob) | |
| { | |
| return _Py_atomic_load_uintptr_relaxed(&ob->ob_tid) == _Py_ThreadId(); | |
| return ob->ob_tid == _Py_ThreadId(); | |
| } | |
| static inline Py_ssize_t Py_REFCNT(PyObject *ob) { | |
| return ob->ob_refcnt; | |
| uint32_t local = _Py_atomic_load_uint32_relaxed(&ob->ob_ref_local); | |
| if (local == _Py_IMMORTAL_REFCNT_LOCAL) { | |
| return _Py_IMMORTAL_REFCNT; | |
| } | |
| Py_ssize_t shared = _Py_atomic_load_ssize_relaxed(&ob->ob_ref_shared); | |
| return _Py_STATIC_CAST(Py_ssize_t, local) + | |
| Py_ARITHMETIC_RIGHT_SHIFT(Py_ssize_t, shared, _Py_REF_SHARED_SHIFT); | |
| } | |
| // bpo-39573: The Py_SET_TYPE() function must be used to set an object type. | |
| static inline PyTypeObject* Py_TYPE(PyObject *ob) { | |
| return ob->ob_type; | |
| } | |
| PyAPI_DATA(PyTypeObject) PyLong_Type; | |
| PyAPI_DATA(PyTypeObject) PyBool_Type; | |
| // bpo-39573: The Py_SET_SIZE() function must be used to set an object size. | |
| static inline Py_ssize_t Py_SIZE(PyObject *ob) { | |
| assert(ob->ob_type != &PyLong_Type); | |
| assert(ob->ob_type != &PyBool_Type); | |
| return _PyVarObject_CAST(ob)->ob_size; | |
| } | |
| static inline Py_ALWAYS_INLINE int _Py_IsImmortal(PyObject *op) | |
| { | |
| return (_Py_atomic_load_uint32_relaxed(&op->ob_ref_local) == | |
| _Py_IMMORTAL_REFCNT_LOCAL); | |
| return (_Py_CAST(PY_INT32_T, op->ob_refcnt) < 0); | |
| return (op->ob_refcnt == _Py_IMMORTAL_REFCNT); | |
| } | |
| static inline int Py_IS_TYPE(PyObject *ob, PyTypeObject *type) { | |
| return Py_TYPE(ob) == type; | |
| } | |
| // Py_SET_REFCNT() implementation for stable ABI | |
| PyAPI_FUNC(void) _Py_SetRefcnt(PyObject *ob, Py_ssize_t refcnt); | |
| static inline void Py_SET_REFCNT(PyObject *ob, Py_ssize_t refcnt) { | |
| // Stable ABI implements Py_SET_REFCNT() as a function call | |
| // on limited C API version 3.13 and newer. | |
| _Py_SetRefcnt(ob, refcnt); | |
| // This immortal check is for code that is unaware of immortal objects. | |
| // The runtime tracks these objects and we should avoid as much | |
| // as possible having extensions inadvertently change the refcnt | |
| // of an immortalized object. | |
| if (_Py_IsImmortal(ob)) { | |
| return; | |
| } | |
| ob->ob_refcnt = refcnt; | |
| if (_Py_IsOwnedByCurrentThread(ob)) { | |
| if ((size_t)refcnt > (size_t)UINT32_MAX) { | |
| // On overflow, make the object immortal | |
| ob->ob_tid = _Py_UNOWNED_TID; | |
| ob->ob_ref_local = _Py_IMMORTAL_REFCNT_LOCAL; | |
| ob->ob_ref_shared = 0; | |
| } | |
| else { | |
| // Set local refcount to desired refcount and shared refcount | |
| // to zero, but preserve the shared refcount flags. | |
| ob->ob_ref_local = _Py_STATIC_CAST(uint32_t, refcnt); | |
| ob->ob_ref_shared &= _Py_REF_SHARED_FLAG_MASK; | |
| } | |
| } | |
| else { | |
| // Set local refcount to zero and shared refcount to desired refcount. | |
| // Mark the object as merged. | |
| ob->ob_tid = _Py_UNOWNED_TID; | |
| ob->ob_ref_local = 0; | |
| ob->ob_ref_shared = _Py_REF_SHARED(refcnt, _Py_REF_MERGED); | |
| } | |
| } | |
| static inline void Py_SET_TYPE(PyObject *ob, PyTypeObject *type) { | |
| ob->ob_type = type; | |
| } | |
| static inline void Py_SET_SIZE(PyVarObject *ob, Py_ssize_t size) { | |
| assert(ob->ob_base.ob_type != &PyLong_Type); | |
| assert(ob->ob_base.ob_type != &PyBool_Type); | |
| _Py_atomic_store_ssize_relaxed(&ob->ob_size, size); | |
| ob->ob_size = size; | |
| } | |
| /* | |
| Type objects contain a string containing the type name (to help somewhat | |
| in debugging), the allocation parameters (see PyObject_New() and | |
| PyObject_NewVar()), | |
| and methods for accessing objects of the type. Methods are optional, a | |
| nil pointer meaning that particular kind of access is not available for | |
| this type. The Py_DECREF() macro uses the tp_dealloc method without | |
| checking for a nil pointer; it should always be implemented except if | |
| the implementation can guarantee that the reference count will never | |
| reach zero (e.g., for statically allocated type objects). | |
| NB: the methods for certain type groups are now contained in separate | |
| method blocks. | |
| */ | |
| typedef PyObject * (*unaryfunc)(PyObject *); | |
| typedef PyObject * (*binaryfunc)(PyObject *, PyObject *); | |
| typedef PyObject * (*ternaryfunc)(PyObject *, PyObject *, PyObject *); | |
| typedef int (*inquiry)(PyObject *); | |
| typedef Py_ssize_t (*lenfunc)(PyObject *); | |
| typedef PyObject *(*ssizeargfunc)(PyObject *, Py_ssize_t); | |
| typedef PyObject *(*ssizessizeargfunc)(PyObject *, Py_ssize_t, Py_ssize_t); | |
| typedef int(*ssizeobjargproc)(PyObject *, Py_ssize_t, PyObject *); | |
| typedef int(*ssizessizeobjargproc)(PyObject *, Py_ssize_t, Py_ssize_t, PyObject *); | |
| typedef int(*objobjargproc)(PyObject *, PyObject *, PyObject *); | |
| typedef int (*objobjproc)(PyObject *, PyObject *); | |
| typedef int (*visitproc)(PyObject *, void *); | |
| typedef int (*traverseproc)(PyObject *, visitproc, void *); | |
| typedef void (*freefunc)(void *); | |
| typedef void (*destructor)(PyObject *); | |
| typedef PyObject *(*getattrfunc)(PyObject *, char *); | |
| typedef PyObject *(*getattrofunc)(PyObject *, PyObject *); | |
| typedef int (*setattrfunc)(PyObject *, char *, PyObject *); | |
| typedef int (*setattrofunc)(PyObject *, PyObject *, PyObject *); | |
| typedef PyObject *(*reprfunc)(PyObject *); | |
| typedef Py_hash_t (*hashfunc)(PyObject *); | |
| typedef PyObject *(*richcmpfunc) (PyObject *, PyObject *, int); | |
| typedef PyObject *(*getiterfunc) (PyObject *); | |
| typedef PyObject *(*iternextfunc) (PyObject *); | |
| typedef PyObject *(*descrgetfunc) (PyObject *, PyObject *, PyObject *); | |
| typedef int (*descrsetfunc) (PyObject *, PyObject *, PyObject *); | |
| typedef int (*initproc)(PyObject *, PyObject *, PyObject *); | |
| typedef PyObject *(*newfunc)(PyTypeObject *, PyObject *, PyObject *); | |
| typedef PyObject *(*allocfunc)(PyTypeObject *, Py_ssize_t); | |
| typedef PyObject *(*vectorcallfunc)(PyObject *callable, PyObject *const *args, | |
| size_t nargsf, PyObject *kwnames); | |
| typedef struct{ | |
| int slot; /* slot id, see below */ | |
| void *pfunc; /* function pointer */ | |
| } PyType_Slot; | |
| typedef struct{ | |
| const char* name; | |
| int basicsize; | |
| int itemsize; | |
| unsigned int flags; | |
| PyType_Slot *slots; /* terminated by slot==0. */ | |
| } PyType_Spec; | |
| PyAPI_FUNC(PyObject*) PyType_FromSpec(PyType_Spec*); | |
| PyAPI_FUNC(PyObject*) PyType_FromSpecWithBases(PyType_Spec*, PyObject*); | |
| PyAPI_FUNC(void*) PyType_GetSlot(PyTypeObject*, int); | |
| PyAPI_FUNC(PyObject*) PyType_FromModuleAndSpec(PyObject *, PyType_Spec *, PyObject *); | |
| PyAPI_FUNC(PyObject *) PyType_GetModule(PyTypeObject *); | |
| PyAPI_FUNC(void *) PyType_GetModuleState(PyTypeObject *); | |
| PyAPI_FUNC(PyObject *) PyType_GetName(PyTypeObject *); | |
| PyAPI_FUNC(PyObject *) PyType_GetQualName(PyTypeObject *); | |
| PyAPI_FUNC(PyObject *) PyType_GetFullyQualifiedName(PyTypeObject *type); | |
| PyAPI_FUNC(PyObject *) PyType_GetModuleName(PyTypeObject *type); | |
| PyAPI_FUNC(PyObject *) PyType_FromMetaclass(PyTypeObject*, PyObject*, PyType_Spec*, PyObject*); | |
| PyAPI_FUNC(void *) PyObject_GetTypeData(PyObject *obj, PyTypeObject *cls); | |
| PyAPI_FUNC(Py_ssize_t) PyType_GetTypeDataSize(PyTypeObject *cls); | |
| /* Generic type check */ | |
| PyAPI_FUNC(int) PyType_IsSubtype(PyTypeObject *, PyTypeObject *); | |
| static inline int PyObject_TypeCheck(PyObject *ob, PyTypeObject *type) { | |
| return Py_IS_TYPE(ob, type) || PyType_IsSubtype(Py_TYPE(ob), type); | |
| } | |
| PyAPI_DATA(PyTypeObject) PyType_Type; /* built-in 'type' */ | |
| PyAPI_DATA(PyTypeObject) PyBaseObject_Type; /* built-in 'object' */ | |
| PyAPI_DATA(PyTypeObject) PySuper_Type; /* built-in 'super' */ | |
| PyAPI_FUNC(unsigned long) PyType_GetFlags(PyTypeObject*); | |
| PyAPI_FUNC(int) PyType_Ready(PyTypeObject *); | |
| PyAPI_FUNC(PyObject *) PyType_GenericAlloc(PyTypeObject *, Py_ssize_t); | |
| PyAPI_FUNC(PyObject *) PyType_GenericNew(PyTypeObject *, | |
| PyObject *, PyObject *); | |
| PyAPI_FUNC(unsigned int) PyType_ClearCache(void); | |
| PyAPI_FUNC(void) PyType_Modified(PyTypeObject *); | |
| /* Generic operations on objects */ | |
| PyAPI_FUNC(PyObject *) PyObject_Repr(PyObject *); | |
| PyAPI_FUNC(PyObject *) PyObject_Str(PyObject *); | |
| PyAPI_FUNC(PyObject *) PyObject_ASCII(PyObject *); | |
| PyAPI_FUNC(PyObject *) PyObject_Bytes(PyObject *); | |
| PyAPI_FUNC(PyObject *) PyObject_RichCompare(PyObject *, PyObject *, int); | |
| PyAPI_FUNC(int) PyObject_RichCompareBool(PyObject *, PyObject *, int); | |
| PyAPI_FUNC(PyObject *) PyObject_GetAttrString(PyObject *, const char *); | |
| PyAPI_FUNC(int) PyObject_SetAttrString(PyObject *, const char *, PyObject *); | |
| PyAPI_FUNC(int) PyObject_DelAttrString(PyObject *v, const char *name); | |
| PyAPI_FUNC(int) PyObject_HasAttrString(PyObject *, const char *); | |
| PyAPI_FUNC(PyObject *) PyObject_GetAttr(PyObject *, PyObject *); | |
| PyAPI_FUNC(int) PyObject_GetOptionalAttr(PyObject *, PyObject *, PyObject **); | |
| PyAPI_FUNC(int) PyObject_GetOptionalAttrString(PyObject *, const char *, PyObject **); | |
| PyAPI_FUNC(int) PyObject_SetAttr(PyObject *, PyObject *, PyObject *); | |
| PyAPI_FUNC(int) PyObject_DelAttr(PyObject *v, PyObject *name); | |
| PyAPI_FUNC(int) PyObject_HasAttr(PyObject *, PyObject *); | |
| PyAPI_FUNC(int) PyObject_HasAttrWithError(PyObject *, PyObject *); | |
| PyAPI_FUNC(int) PyObject_HasAttrStringWithError(PyObject *, const char *); | |
| PyAPI_FUNC(PyObject *) PyObject_SelfIter(PyObject *); | |
| PyAPI_FUNC(PyObject *) PyObject_GenericGetAttr(PyObject *, PyObject *); | |
| PyAPI_FUNC(int) PyObject_GenericSetAttr(PyObject *, PyObject *, PyObject *); | |
| PyAPI_FUNC(int) PyObject_GenericSetDict(PyObject *, PyObject *, void *); | |
| PyAPI_FUNC(Py_hash_t) PyObject_Hash(PyObject *); | |
| PyAPI_FUNC(Py_hash_t) PyObject_HashNotImplemented(PyObject *); | |
| PyAPI_FUNC(int) PyObject_IsTrue(PyObject *); | |
| PyAPI_FUNC(int) PyObject_Not(PyObject *); | |
| PyAPI_FUNC(int) PyCallable_Check(PyObject *); | |
| PyAPI_FUNC(void) PyObject_ClearWeakRefs(PyObject *); | |
| /* PyObject_Dir(obj) acts like Python builtins.dir(obj), returning a | |
| list of strings. PyObject_Dir(NULL) is like builtins.dir(), | |
| returning the names of the current locals. In this case, if there are | |
| no current locals, NULL is returned, and PyErr_Occurred() is false. | |
| */ | |
| PyAPI_FUNC(PyObject *) PyObject_Dir(PyObject *); | |
| /* Helpers for printing recursive container types */ | |
| PyAPI_FUNC(int) Py_ReprEnter(PyObject *); | |
| PyAPI_FUNC(void) Py_ReprLeave(PyObject *); | |
| /* Flag bits for printing: */ | |
| /* | |
| Type flags (tp_flags) | |
| These flags are used to change expected features and behavior for a | |
| particular type. | |
| Arbitration of the flag bit positions will need to be coordinated among | |
| all extension writers who publicly release their extensions (this will | |
| be fewer than you might expect!). | |
| Most flags were removed as of Python 3.0 to make room for new flags. (Some | |
| flags are not for backwards compatibility but to indicate the presence of an | |
| optional feature; these flags remain of course.) | |
| Type definitions should use Py_TPFLAGS_DEFAULT for their tp_flags value. | |
| Code can use PyType_HasFeature(type_ob, flag_value) to test whether the | |
| given type object has a specified feature. | |
| */ | |
| /* Track types initialized using _PyStaticType_InitBuiltin(). */ | |
| /* The values array is placed inline directly after the rest of | |
| * the object. Implies Py_TPFLAGS_HAVE_GC. | |
| */ | |
| /* Placement of weakref pointers are managed by the VM, not by the type. | |
| * The VM will automatically set tp_weaklistoffset. | |
| */ | |
| /* Placement of dict (and values) pointers are managed by the VM, not by the type. | |
| * The VM will automatically set tp_dictoffset. Implies Py_TPFLAGS_HAVE_GC. | |
| */ | |
| /* Set if instances of the type object are treated as sequences for pattern matching */ | |
| /* Set if instances of the type object are treated as mappings for pattern matching */ | |
| /* Disallow creating instances of the type: set tp_new to NULL and don't create | |
| * the "__new__" key in the type dictionary. */ | |
| /* Set if the type object is immutable: type attributes cannot be set nor deleted */ | |
| /* Set if the type object is dynamically allocated */ | |
| /* Set if the type allows subclassing */ | |
| /* Set if the type implements the vectorcall protocol (PEP 590) */ | |
| // Backwards compatibility alias for API that was provisional in Python 3.8 | |
| /* Set if the type is 'ready' -- fully initialized */ | |
| /* Set while the type is being 'readied', to prevent recursive ready calls */ | |
| /* Objects support garbage collection (see objimpl.h) */ | |
| /* These two bits are preserved for Stackless Python, next after this is 17 */ | |
| /* Objects behave like an unbound method */ | |
| /* Unused. Legacy flag */ | |
| /* Type is abstract and cannot be instantiated */ | |
| // This undocumented flag gives certain built-ins their unique pattern-matching | |
| // behavior, which allows a single positional subpattern to match against the | |
| // subject itself (rather than a mapped attribute on it): | |
| /* Items (ob_size*tp_itemsize) are found at the end of an instance's memory */ | |
| /* These flags are used to determine if a type is a subclass. */ | |
| /* NOTE: Some of the following flags reuse lower bits (removed as part of the | |
| * Python 3.0 transition). */ | |
| /* The following flags are kept for compatibility; in previous | |
| * versions they indicated presence of newer tp_* fields on the | |
| * type struct. | |
| * Starting with 3.8, binary compatibility of C extensions across | |
| * feature releases of Python is not supported anymore (except when | |
| * using the stable ABI, in which all classes are created dynamically, | |
| * using the interpreter's memory layout.) | |
| * Note that older extensions using the stable ABI set these flags, | |
| * so the bits must not be repurposed. | |
| */ | |
| /* | |
| The macros Py_INCREF(op) and Py_DECREF(op) are used to increment or decrement | |
| reference counts. Py_DECREF calls the object's deallocator function when | |
| the refcount falls to 0; for | |
| objects that don't contain references to other objects or heap memory | |
| this can be the standard function free(). Both macros can be used | |
| wherever a void expression is allowed. The argument must not be a | |
| NULL pointer. If it may be NULL, use Py_XINCREF/Py_XDECREF instead. | |
| The macro _Py_NewReference(op) initialize reference counts to 1, and | |
| in special builds (Py_REF_DEBUG, Py_TRACE_REFS) performs additional | |
| bookkeeping appropriate to the special build. | |
| We assume that the reference count field can never overflow; this can | |
| be proven when the size of the field is the same as the pointer size, so | |
| we ignore the possibility. Provided a C int is at least 32 bits (which | |
| is implicitly assumed in many parts of this code), that's enough for | |
| about 2**31 references to an object. | |
| XXX The following became out of date in Python 2.2, but I'm not sure | |
| XXX what the full truth is now. Certainly, heap-allocated type objects | |
| XXX can and should be deallocated. | |
| Type objects should never be deallocated; the type pointer in an object | |
| is not considered to be a reference to the type object, to save | |
| complications in the deallocation function. (This is actually a | |
| decision that's up to the implementer of each new type so if you want, | |
| you can count such references to the type object.) | |
| */ | |
| PyAPI_FUNC(void) _Py_NegativeRefcount(const char *filename, int lineno, | |
| PyObject *op); | |
| PyAPI_FUNC(void) _Py_INCREF_IncRefTotal(void); | |
| PyAPI_FUNC(void) _Py_DECREF_DecRefTotal(void); | |
| PyAPI_FUNC(void) _Py_Dealloc(PyObject *); | |
| /* | |
| These are provided as conveniences to Python runtime embedders, so that | |
| they can have object code that is not dependent on Python compilation flags. | |
| */ | |
| PyAPI_FUNC(void) Py_IncRef(PyObject *); | |
| PyAPI_FUNC(void) Py_DecRef(PyObject *); | |
| // Similar to Py_IncRef() and Py_DecRef() but the argument must be non-NULL. | |
| // Private functions used by Py_INCREF() and Py_DECREF(). | |
| PyAPI_FUNC(void) _Py_IncRef(PyObject *); | |
| PyAPI_FUNC(void) _Py_DecRef(PyObject *); | |
| static inline Py_ALWAYS_INLINE void Py_INCREF(PyObject *op) | |
| { | |
| // Stable ABI implements Py_INCREF() as a function call on limited C API | |
| // version 3.12 and newer, and on Python built in debug mode. _Py_IncRef() | |
| // was added to Python 3.10.0a7, use Py_IncRef() on older Python versions. | |
| // Py_IncRef() accepts NULL whereas _Py_IncRef() doesn't. | |
| _Py_IncRef(op); | |
| Py_IncRef(op); | |
| // Non-limited C API and limited C API for Python 3.9 and older access | |
| // directly PyObject.ob_refcnt. | |
| uint32_t local = _Py_atomic_load_uint32_relaxed(&op->ob_ref_local); | |
| uint32_t new_local = local + 1; | |
| if (new_local == 0) { | |
| // local is equal to _Py_IMMORTAL_REFCNT: do nothing | |
| return; | |
| } | |
| if (_Py_IsOwnedByCurrentThread(op)) { | |
| _Py_atomic_store_uint32_relaxed(&op->ob_ref_local, new_local); | |
| } | |
| else { | |
| _Py_atomic_add_ssize(&op->ob_ref_shared, (1 << _Py_REF_SHARED_SHIFT)); | |
| } | |
| // Portable saturated add, branching on the carry flag and set low bits | |
| PY_UINT32_T cur_refcnt = op->ob_refcnt_split[PY_BIG_ENDIAN]; | |
| PY_UINT32_T new_refcnt = cur_refcnt + 1; | |
| if (new_refcnt == 0) { | |
| // cur_refcnt is equal to _Py_IMMORTAL_REFCNT: the object is immortal, | |
| // do nothing | |
| return; | |
| } | |
| op->ob_refcnt_split[PY_BIG_ENDIAN] = new_refcnt; | |
| // Explicitly check immortality against the immortal value | |
| if (_Py_IsImmortal(op)) { | |
| return; | |
| } | |
| op->ob_refcnt++; | |
| _Py_INCREF_STAT_INC(); | |
| _Py_INCREF_IncRefTotal(); | |
| } | |
| // Implements Py_DECREF on objects not owned by the current thread. | |
| PyAPI_FUNC(void) _Py_DecRefShared(PyObject *); | |
| PyAPI_FUNC(void) _Py_DecRefSharedDebug(PyObject *, const char *, int); | |
| // Called from Py_DECREF by the owning thread when the local refcount reaches | |
| // zero. The call will deallocate the object if the shared refcount is also | |
| // zero. Otherwise, the thread gives up ownership and merges the reference | |
| // count fields. | |
| PyAPI_FUNC(void) _Py_MergeZeroLocalRefcount(PyObject *); | |
| // Stable ABI implements Py_DECREF() as a function call on limited C API | |
| // version 3.12 and newer, and on Python built in debug mode. _Py_DecRef() was | |
| // added to Python 3.10.0a7, use Py_DecRef() on older Python versions. | |
| // Py_DecRef() accepts NULL whereas _Py_IncRef() doesn't. | |
| static inline void Py_DECREF(PyObject *op) { | |
| _Py_DecRef(op); | |
| Py_DecRef(op); | |
| } | |
| static inline void Py_DECREF(const char *filename, int lineno, PyObject *op) | |
| { | |
| uint32_t local = _Py_atomic_load_uint32_relaxed(&op->ob_ref_local); | |
| if (local == _Py_IMMORTAL_REFCNT_LOCAL) { | |
| return; | |
| } | |
| _Py_DECREF_STAT_INC(); | |
| _Py_DECREF_DecRefTotal(); | |
| if (_Py_IsOwnedByCurrentThread(op)) { | |
| if (local == 0) { | |
| _Py_NegativeRefcount(filename, lineno, op); | |
| } | |
| local--; | |
| _Py_atomic_store_uint32_relaxed(&op->ob_ref_local, local); | |
| if (local == 0) { | |
| _Py_MergeZeroLocalRefcount(op); | |
| } | |
| } | |
| else { | |
| _Py_DecRefSharedDebug(op, filename, lineno); | |
| } | |
| } | |
| static inline void Py_DECREF(PyObject *op) | |
| { | |
| uint32_t local = _Py_atomic_load_uint32_relaxed(&op->ob_ref_local); | |
| if (local == _Py_IMMORTAL_REFCNT_LOCAL) { | |
| return; | |
| } | |
| _Py_DECREF_STAT_INC(); | |
| if (_Py_IsOwnedByCurrentThread(op)) { | |
| local--; | |
| _Py_atomic_store_uint32_relaxed(&op->ob_ref_local, local); | |
| if (local == 0) { | |
| _Py_MergeZeroLocalRefcount(op); | |
| } | |
| } | |
| else { | |
| _Py_DecRefShared(op); | |
| } | |
| } | |
| static inline void Py_DECREF(const char *filename, int lineno, PyObject *op) | |
| { | |
| if (op->ob_refcnt <= 0) { | |
| _Py_NegativeRefcount(filename, lineno, op); | |
| } | |
| if (_Py_IsImmortal(op)) { | |
| return; | |
| } | |
| _Py_DECREF_STAT_INC(); | |
| _Py_DECREF_DecRefTotal(); | |
| if (--op->ob_refcnt == 0) { | |
| _Py_Dealloc(op); | |
| } | |
| } | |
| static inline Py_ALWAYS_INLINE void Py_DECREF(PyObject *op) | |
| { | |
| // Non-limited C API and limited C API for Python 3.9 and older access | |
| // directly PyObject.ob_refcnt. | |
| if (_Py_IsImmortal(op)) { | |
| return; | |
| } | |
| _Py_DECREF_STAT_INC(); | |
| if (--op->ob_refcnt == 0) { | |
| _Py_Dealloc(op); | |
| } | |
| } | |
| /* Safely decref `op` and set `op` to NULL, especially useful in tp_clear | |
| * and tp_dealloc implementations. | |
| * | |
| * Note that "the obvious" code can be deadly: | |
| * | |
| * Py_XDECREF(op); | |
| * op = NULL; | |
| * | |
| * Typically, `op` is something like self->containee, and `self` is done | |
| * using its `containee` member. In the code sequence above, suppose | |
| * `containee` is non-NULL with a refcount of 1. Its refcount falls to | |
| * 0 on the first line, which can trigger an arbitrary amount of code, | |
| * possibly including finalizers (like __del__ methods or weakref callbacks) | |
| * coded in Python, which in turn can release the GIL and allow other threads | |
| * to run, etc. Such code may even invoke methods of `self` again, or cause | |
| * cyclic gc to trigger, but-- oops! --self->containee still points to the | |
| * object being torn down, and it may be in an insane state while being torn | |
| * down. This has in fact been a rich historic source of miserable (rare & | |
| * hard-to-diagnose) segfaulting (and other) bugs. | |
| * | |
| * The safe way is: | |
| * | |
| * Py_CLEAR(op); | |
| * | |
| * That arranges to set `op` to NULL _before_ decref'ing, so that any code | |
| * triggered as a side-effect of `op` getting torn down no longer believes | |
| * `op` points to a valid object. | |
| * | |
| * There are cases where it's safe to use the naive code, but they're brittle. | |
| * For example, if `op` points to a Python integer, you know that destroying | |
| * one of those can't cause problems -- but in part that relies on that | |
| * Python integers aren't currently weakly referencable. Best practice is | |
| * to use Py_CLEAR() even if you can't think of a reason for why you need to. | |
| * | |
| * gh-98724: Use a temporary variable to only evaluate the macro argument once, | |
| * to avoid the duplication of side effects if the argument has side effects. | |
| * | |
| * gh-99701: If the PyObject* type is used with casting arguments to PyObject*, | |
| * the code can be miscompiled with strict aliasing because of type punning. | |
| * With strict aliasing, a compiler considers that two pointers of different | |
| * types cannot read or write the same memory which enables optimization | |
| * opportunities. | |
| * | |
| * If available, use _Py_TYPEOF() to use the 'op' type for temporary variables, | |
| * and so avoid type punning. Otherwise, use memcpy() which causes type erasure | |
| * and so prevents the compiler to reuse an old cached 'op' value after | |
| * Py_CLEAR(). | |
| */ | |
| /* Function to use in case the object pointer can be NULL: */ | |
| static inline void Py_XINCREF(PyObject *op) | |
| { | |
| if (op != _Py_NULL) { | |
| Py_INCREF(op); | |
| } | |
| } | |
| static inline void Py_XDECREF(PyObject *op) | |
| { | |
| if (op != _Py_NULL) { | |
| Py_DECREF(op); | |
| } | |
| } | |
| // Create a new strong reference to an object: | |
| // increment the reference count of the object and return the object. | |
| PyAPI_FUNC(PyObject*) Py_NewRef(PyObject *obj); | |
| // Similar to Py_NewRef(), but the object can be NULL. | |
| PyAPI_FUNC(PyObject*) Py_XNewRef(PyObject *obj); | |
| static inline PyObject* _Py_NewRef(PyObject *obj) | |
| { | |
| Py_INCREF(obj); | |
| return obj; | |
| } | |
| static inline PyObject* _Py_XNewRef(PyObject *obj) | |
| { | |
| Py_XINCREF(obj); | |
| return obj; | |
| } | |
| // Py_NewRef() and Py_XNewRef() are exported as functions for the stable ABI. | |
| // Names overridden with macros by static inline functions for best | |
| // performances. | |
| PyAPI_FUNC(PyObject*) Py_GetConstant(unsigned int constant_id); | |
| PyAPI_FUNC(PyObject*) Py_GetConstantBorrowed(unsigned int constant_id); | |
| /* | |
| _Py_NoneStruct is an object of undefined type which can be used in contexts | |
| where NULL (nil) is not suitable (since NULL often means 'error'). | |
| */ | |
| PyAPI_DATA(PyObject) _Py_NoneStruct; /* Don't use this directly */ | |
| // Test if an object is the None singleton, the same as "x is None" in Python. | |
| PyAPI_FUNC(int) Py_IsNone(PyObject *x); | |
| /* Macro for returning Py_None from a function. | |
| * Only treat Py_None as immortal in the limited C API 3.12 and newer. */ | |
| /* | |
| Py_NotImplemented is a singleton used to signal that an operation is | |
| not implemented for a given type combination. | |
| */ | |
| PyAPI_DATA(PyObject) _Py_NotImplementedStruct; /* Don't use this directly */ | |
| /* Macro for returning Py_NotImplemented from a function. Only treat | |
| * Py_NotImplemented as immortal in the limited C API 3.12 and newer. */ | |
| /* Rich comparison opcodes */ | |
| /* Result of calling PyIter_Send */ | |
| typedef enum { | |
| PYGEN_RETURN = 0, | |
| PYGEN_ERROR = -1, | |
| PYGEN_NEXT = 1, | |
| } PySendResult; | |
| /* | |
| * Macro for implementing rich comparisons | |
| * | |
| * Needs to be a macro because any C-comparable type can be used. | |
| */ | |
| /* | |
| More conventions | |
| ================ | |
| Argument Checking | |
| ----------------- | |
| Functions that take objects as arguments normally don't check for nil | |
| arguments, but they do check the type of the argument, and return an | |
| error if the function doesn't apply to the type. | |
| Failure Modes | |
| ------------- | |
| Functions may fail for a variety of reasons, including running out of | |
| memory. This is communicated to the caller in two ways: an error string | |
| is set (see errors.h), and the function result differs: functions that | |
| normally return a pointer return NULL for failure, functions returning | |
| an integer return -1 (which could be a legal return value too!), and | |
| other functions return 0 for success and -1 for failure. | |
| Callers should always check for errors before using the result. If | |
| an error was set, the caller must either explicitly clear it, or pass | |
| the error on to its caller. | |
| Reference Counts | |
| ---------------- | |
| It takes a while to get used to the proper usage of reference counts. | |
| Functions that create an object set the reference count to 1; such new | |
| objects must be stored somewhere or destroyed again with Py_DECREF(). | |
| Some functions that 'store' objects, such as PyTuple_SetItem() and | |
| PyList_SetItem(), | |
| don't increment the reference count of the object, since the most | |
| frequent use is to store a fresh object. Functions that 'retrieve' | |
| objects, such as PyTuple_GetItem() and PyDict_GetItemString(), also | |
| don't increment | |
| the reference count, since most frequently the object is only looked at | |
| quickly. Thus, to retrieve an object and store it again, the caller | |
| must call Py_INCREF() explicitly. | |
| NOTE: functions that 'consume' a reference count, like | |
| PyList_SetItem(), consume the reference even if the object wasn't | |
| successfully stored, to simplify error handling. | |
| It seems attractive to make other functions that take an object as | |
| argument consume a reference count; however, this may quickly get | |
| confusing (even the current practice is already confusing). Consider | |
| it carefully, it may save lots of calls to Py_INCREF() and Py_DECREF() at | |
| times. | |
| */ | |
| static inline int | |
| PyType_HasFeature(PyTypeObject *type, unsigned long feature) | |
| { | |
| unsigned long flags; | |
| // PyTypeObject is opaque in the limited C API | |
| flags = PyType_GetFlags(type); | |
| flags = _Py_atomic_load_ulong_relaxed(&type->tp_flags); | |
| flags = type->tp_flags; | |
| return ((flags & feature) != 0); | |
| } | |
| static inline int PyType_Check(PyObject *op) { | |
| return PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_TYPE_SUBCLASS); | |
| } | |
| static inline int PyType_CheckExact(PyObject *op) { | |
| return Py_IS_TYPE(op, &PyType_Type); | |
| } | |
| PyAPI_FUNC(PyObject *) PyType_GetModuleByDef(PyTypeObject *, PyModuleDef *); | |
| } | |
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