| #ifndef Py_OBJECT_H |
| #define Py_OBJECT_H |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| |
| /* 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_TRACE_REFS. */ |
| #if defined(Py_DEBUG) && !defined(Py_TRACE_REFS) |
| #define Py_TRACE_REFS |
| #endif |
| |
| /* Py_TRACE_REFS implies Py_REF_DEBUG. */ |
| #if defined(Py_TRACE_REFS) && !defined(Py_REF_DEBUG) |
| #define Py_REF_DEBUG |
| #endif |
| |
| #ifdef Py_TRACE_REFS |
| /* Define pointers to support a doubly-linked list of all live heap objects. */ |
| #define _PyObject_HEAD_EXTRA \ |
| struct _object *_ob_next; \ |
| struct _object *_ob_prev; |
| |
| #define _PyObject_EXTRA_INIT 0, 0, |
| |
| #else |
| #define _PyObject_HEAD_EXTRA |
| #define _PyObject_EXTRA_INIT |
| #endif |
| |
| /* PyObject_HEAD defines the initial segment of every PyObject. */ |
| #define PyObject_HEAD \ |
| _PyObject_HEAD_EXTRA \ |
| int ob_refcnt; \ |
| struct _typeobject *ob_type; |
| |
| #define PyObject_HEAD_INIT(type) \ |
| _PyObject_EXTRA_INIT \ |
| 1, type, |
| |
| /* 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. |
| */ |
| #define PyObject_VAR_HEAD \ |
| PyObject_HEAD \ |
| int ob_size; /* Number of items in variable part */ |
| |
| /* 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*. |
| */ |
| typedef struct _object { |
| PyObject_HEAD |
| } PyObject; |
| |
| typedef struct { |
| PyObject_VAR_HEAD |
| } PyVarObject; |
| |
| |
| /* |
| 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 int (*coercion)(PyObject **, PyObject **); |
| typedef PyObject *(*intargfunc)(PyObject *, int); |
| typedef PyObject *(*intintargfunc)(PyObject *, int, int); |
| typedef int(*intobjargproc)(PyObject *, int, PyObject *); |
| typedef int(*intintobjargproc)(PyObject *, int, int, PyObject *); |
| typedef int(*objobjargproc)(PyObject *, PyObject *, PyObject *); |
| typedef int (*getreadbufferproc)(PyObject *, int, void **); |
| typedef int (*getwritebufferproc)(PyObject *, int, void **); |
| typedef int (*getsegcountproc)(PyObject *, int *); |
| typedef int (*getcharbufferproc)(PyObject *, int, const char **); |
| typedef int (*objobjproc)(PyObject *, PyObject *); |
| typedef int (*visitproc)(PyObject *, void *); |
| typedef int (*traverseproc)(PyObject *, visitproc, void *); |
| |
| typedef struct { |
| /* For numbers without flag bit Py_TPFLAGS_CHECKTYPES set, all |
| arguments are guaranteed to be of the object's type (modulo |
| coercion hacks -- i.e. if the type's coercion function |
| returns other types, then these are allowed as well). Numbers that |
| have the Py_TPFLAGS_CHECKTYPES flag bit set should check *both* |
| arguments for proper type and implement the necessary conversions |
| in the slot functions themselves. */ |
| |
| binaryfunc nb_add; |
| binaryfunc nb_subtract; |
| binaryfunc nb_multiply; |
| binaryfunc nb_divide; |
| binaryfunc nb_remainder; |
| binaryfunc nb_divmod; |
| ternaryfunc nb_power; |
| unaryfunc nb_negative; |
| unaryfunc nb_positive; |
| unaryfunc nb_absolute; |
| inquiry nb_nonzero; |
| unaryfunc nb_invert; |
| binaryfunc nb_lshift; |
| binaryfunc nb_rshift; |
| binaryfunc nb_and; |
| binaryfunc nb_xor; |
| binaryfunc nb_or; |
| coercion nb_coerce; |
| unaryfunc nb_int; |
| unaryfunc nb_long; |
| unaryfunc nb_float; |
| unaryfunc nb_oct; |
| unaryfunc nb_hex; |
| /* Added in release 2.0 */ |
| binaryfunc nb_inplace_add; |
| binaryfunc nb_inplace_subtract; |
| binaryfunc nb_inplace_multiply; |
| binaryfunc nb_inplace_divide; |
| binaryfunc nb_inplace_remainder; |
| ternaryfunc nb_inplace_power; |
| binaryfunc nb_inplace_lshift; |
| binaryfunc nb_inplace_rshift; |
| binaryfunc nb_inplace_and; |
| binaryfunc nb_inplace_xor; |
| binaryfunc nb_inplace_or; |
| |
| /* Added in release 2.2 */ |
| /* The following require the Py_TPFLAGS_HAVE_CLASS flag */ |
| binaryfunc nb_floor_divide; |
| binaryfunc nb_true_divide; |
| binaryfunc nb_inplace_floor_divide; |
| binaryfunc nb_inplace_true_divide; |
| } PyNumberMethods; |
| |
| typedef struct { |
| inquiry sq_length; |
| binaryfunc sq_concat; |
| intargfunc sq_repeat; |
| intargfunc sq_item; |
| intintargfunc sq_slice; |
| intobjargproc sq_ass_item; |
| intintobjargproc sq_ass_slice; |
| objobjproc sq_contains; |
| /* Added in release 2.0 */ |
| binaryfunc sq_inplace_concat; |
| intargfunc sq_inplace_repeat; |
| } PySequenceMethods; |
| |
| typedef struct { |
| inquiry mp_length; |
| binaryfunc mp_subscript; |
| objobjargproc mp_ass_subscript; |
| } PyMappingMethods; |
| |
| typedef struct { |
| getreadbufferproc bf_getreadbuffer; |
| getwritebufferproc bf_getwritebuffer; |
| getsegcountproc bf_getsegcount; |
| getcharbufferproc bf_getcharbuffer; |
| } PyBufferProcs; |
| |
| |
| typedef void (*freefunc)(void *); |
| typedef void (*destructor)(PyObject *); |
| typedef int (*printfunc)(PyObject *, FILE *, int); |
| typedef PyObject *(*getattrfunc)(PyObject *, char *); |
| typedef PyObject *(*getattrofunc)(PyObject *, PyObject *); |
| typedef int (*setattrfunc)(PyObject *, char *, PyObject *); |
| typedef int (*setattrofunc)(PyObject *, PyObject *, PyObject *); |
| typedef int (*cmpfunc)(PyObject *, PyObject *); |
| typedef PyObject *(*reprfunc)(PyObject *); |
| typedef long (*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)(struct _typeobject *, PyObject *, PyObject *); |
| typedef PyObject *(*allocfunc)(struct _typeobject *, int); |
| |
| typedef struct _typeobject { |
| PyObject_VAR_HEAD |
| char *tp_name; /* For printing, in format "<module>.<name>" */ |
| int tp_basicsize, tp_itemsize; /* For allocation */ |
| |
| /* Methods to implement standard operations */ |
| |
| destructor tp_dealloc; |
| printfunc tp_print; |
| getattrfunc tp_getattr; |
| setattrfunc tp_setattr; |
| cmpfunc tp_compare; |
| reprfunc tp_repr; |
| |
| /* Method suites for standard classes */ |
| |
| PyNumberMethods *tp_as_number; |
| PySequenceMethods *tp_as_sequence; |
| PyMappingMethods *tp_as_mapping; |
| |
| /* More standard operations (here for binary compatibility) */ |
| |
| hashfunc tp_hash; |
| ternaryfunc tp_call; |
| reprfunc tp_str; |
| getattrofunc tp_getattro; |
| setattrofunc tp_setattro; |
| |
| /* Functions to access object as input/output buffer */ |
| PyBufferProcs *tp_as_buffer; |
| |
| /* Flags to define presence of optional/expanded features */ |
| long tp_flags; |
| |
| char *tp_doc; /* Documentation string */ |
| |
| /* Assigned meaning in release 2.0 */ |
| /* call function for all accessible objects */ |
| traverseproc tp_traverse; |
| |
| /* delete references to contained objects */ |
| inquiry tp_clear; |
| |
| /* Assigned meaning in release 2.1 */ |
| /* rich comparisons */ |
| richcmpfunc tp_richcompare; |
| |
| /* weak reference enabler */ |
| long tp_weaklistoffset; |
| |
| /* Added in release 2.2 */ |
| /* Iterators */ |
| getiterfunc tp_iter; |
| iternextfunc tp_iternext; |
| |
| /* Attribute descriptor and subclassing stuff */ |
| struct PyMethodDef *tp_methods; |
| struct PyMemberDef *tp_members; |
| struct PyGetSetDef *tp_getset; |
| struct _typeobject *tp_base; |
| PyObject *tp_dict; |
| descrgetfunc tp_descr_get; |
| descrsetfunc tp_descr_set; |
| long tp_dictoffset; |
| initproc tp_init; |
| allocfunc tp_alloc; |
| newfunc tp_new; |
| freefunc tp_free; /* Low-level free-memory routine */ |
| inquiry tp_is_gc; /* For PyObject_IS_GC */ |
| PyObject *tp_bases; |
| PyObject *tp_mro; /* method resolution order */ |
| PyObject *tp_cache; |
| PyObject *tp_subclasses; |
| PyObject *tp_weaklist; |
| destructor tp_del; |
| |
| #ifdef COUNT_ALLOCS |
| /* these must be last and never explicitly initialized */ |
| int tp_allocs; |
| int tp_frees; |
| int tp_maxalloc; |
| struct _typeobject *tp_next; |
| #endif |
| } PyTypeObject; |
| |
| |
| /* The *real* layout of a type object when allocated on the heap */ |
| typedef struct _heaptypeobject { |
| /* Note: there's a dependency on the order of these members |
| in slotptr() in typeobject.c . */ |
| PyTypeObject type; |
| PyNumberMethods as_number; |
| PyMappingMethods as_mapping; |
| PySequenceMethods as_sequence; /* as_sequence comes after as_mapping, |
| so that the mapping wins when both |
| the mapping and the sequence define |
| a given operator (e.g. __getitem__). |
| see add_operators() in typeobject.c . */ |
| PyBufferProcs as_buffer; |
| PyObject *name, *slots; |
| /* here are optional user slots, followed by the members. */ |
| } PyHeapTypeObject; |
| |
| /* access macro to the members which are floating "behind" the object */ |
| #define PyHeapType_GET_MEMBERS(etype) \ |
| ((PyMemberDef *)(((char *)etype) + (etype)->type.ob_type->tp_basicsize)) |
| |
| |
| /* Generic type check */ |
| PyAPI_FUNC(int) PyType_IsSubtype(PyTypeObject *, PyTypeObject *); |
| #define PyObject_TypeCheck(ob, tp) \ |
| ((ob)->ob_type == (tp) || PyType_IsSubtype((ob)->ob_type, (tp))) |
| |
| PyAPI_DATA(PyTypeObject) PyType_Type; /* built-in 'type' */ |
| PyAPI_DATA(PyTypeObject) PyBaseObject_Type; /* built-in 'object' */ |
| PyAPI_DATA(PyTypeObject) PySuper_Type; /* built-in 'super' */ |
| |
| #define PyType_Check(op) PyObject_TypeCheck(op, &PyType_Type) |
| #define PyType_CheckExact(op) ((op)->ob_type == &PyType_Type) |
| |
| PyAPI_FUNC(int) PyType_Ready(PyTypeObject *); |
| PyAPI_FUNC(PyObject *) PyType_GenericAlloc(PyTypeObject *, int); |
| PyAPI_FUNC(PyObject *) PyType_GenericNew(PyTypeObject *, |
| PyObject *, PyObject *); |
| PyAPI_FUNC(PyObject *) _PyType_Lookup(PyTypeObject *, PyObject *); |
| |
| /* Generic operations on objects */ |
| PyAPI_FUNC(int) PyObject_Print(PyObject *, FILE *, int); |
| PyAPI_FUNC(void) _PyObject_Dump(PyObject *); |
| PyAPI_FUNC(PyObject *) PyObject_Repr(PyObject *); |
| PyAPI_FUNC(PyObject *) PyObject_Str(PyObject *); |
| #ifdef Py_USING_UNICODE |
| PyAPI_FUNC(PyObject *) PyObject_Unicode(PyObject *); |
| #endif |
| PyAPI_FUNC(int) PyObject_Compare(PyObject *, PyObject *); |
| PyAPI_FUNC(PyObject *) PyObject_RichCompare(PyObject *, PyObject *, int); |
| PyAPI_FUNC(int) PyObject_RichCompareBool(PyObject *, PyObject *, int); |
| PyAPI_FUNC(PyObject *) PyObject_GetAttrString(PyObject *, char *); |
| PyAPI_FUNC(int) PyObject_SetAttrString(PyObject *, char *, PyObject *); |
| PyAPI_FUNC(int) PyObject_HasAttrString(PyObject *, char *); |
| PyAPI_FUNC(PyObject *) PyObject_GetAttr(PyObject *, PyObject *); |
| PyAPI_FUNC(int) PyObject_SetAttr(PyObject *, PyObject *, PyObject *); |
| PyAPI_FUNC(int) PyObject_HasAttr(PyObject *, PyObject *); |
| PyAPI_FUNC(PyObject **) _PyObject_GetDictPtr(PyObject *); |
| PyAPI_FUNC(PyObject *) PyObject_SelfIter(PyObject *); |
| PyAPI_FUNC(PyObject *) PyObject_GenericGetAttr(PyObject *, PyObject *); |
| PyAPI_FUNC(int) PyObject_GenericSetAttr(PyObject *, |
| PyObject *, PyObject *); |
| PyAPI_FUNC(long) PyObject_Hash(PyObject *); |
| PyAPI_FUNC(int) PyObject_IsTrue(PyObject *); |
| PyAPI_FUNC(int) PyObject_Not(PyObject *); |
| PyAPI_FUNC(int) PyCallable_Check(PyObject *); |
| PyAPI_FUNC(int) PyNumber_Coerce(PyObject **, PyObject **); |
| PyAPI_FUNC(int) PyNumber_CoerceEx(PyObject **, PyObject **); |
| |
| PyAPI_FUNC(void) PyObject_ClearWeakRefs(PyObject *); |
| |
| /* A slot function whose address we need to compare */ |
| extern int _PyObject_SlotCompare(PyObject *, PyObject *); |
| |
| |
| /* PyObject_Dir(obj) acts like Python __builtin__.dir(obj), returning a |
| list of strings. PyObject_Dir(NULL) is like __builtin__.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 *); |
| |
| /* Helpers for hash functions */ |
| PyAPI_FUNC(long) _Py_HashDouble(double); |
| PyAPI_FUNC(long) _Py_HashPointer(void*); |
| |
| /* Helper for passing objects to printf and the like */ |
| #define PyObject_REPR(obj) PyString_AS_STRING(PyObject_Repr(obj)) |
| |
| /* Flag bits for printing: */ |
| #define Py_PRINT_RAW 1 /* No string quotes etc. */ |
| |
| /* |
| `Type flags (tp_flags) |
| |
| These flags are used to extend the type structure in a backwards-compatible |
| fashion. Extensions can use the flags to indicate (and test) when a given |
| type structure contains a new feature. The Python core will use these when |
| introducing new functionality between major revisions (to avoid mid-version |
| changes in the PYTHON_API_VERSION). |
| |
| Arbitration of the flag bit positions will need to be coordinated among |
| all extension writers who publically release their extensions (this will |
| be fewer than you might expect!).. |
| |
| Python 1.5.2 introduced the bf_getcharbuffer slot into PyBufferProcs. |
| |
| 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. |
| */ |
| |
| /* PyBufferProcs contains bf_getcharbuffer */ |
| #define Py_TPFLAGS_HAVE_GETCHARBUFFER (1L<<0) |
| |
| /* PySequenceMethods contains sq_contains */ |
| #define Py_TPFLAGS_HAVE_SEQUENCE_IN (1L<<1) |
| |
| /* This is here for backwards compatibility. Extensions that use the old GC |
| * API will still compile but the objects will not be tracked by the GC. */ |
| #define Py_TPFLAGS_GC 0 /* used to be (1L<<2) */ |
| |
| /* PySequenceMethods and PyNumberMethods contain in-place operators */ |
| #define Py_TPFLAGS_HAVE_INPLACEOPS (1L<<3) |
| |
| /* PyNumberMethods do their own coercion */ |
| #define Py_TPFLAGS_CHECKTYPES (1L<<4) |
| |
| /* tp_richcompare is defined */ |
| #define Py_TPFLAGS_HAVE_RICHCOMPARE (1L<<5) |
| |
| /* Objects which are weakly referencable if their tp_weaklistoffset is >0 */ |
| #define Py_TPFLAGS_HAVE_WEAKREFS (1L<<6) |
| |
| /* tp_iter is defined */ |
| #define Py_TPFLAGS_HAVE_ITER (1L<<7) |
| |
| /* New members introduced by Python 2.2 exist */ |
| #define Py_TPFLAGS_HAVE_CLASS (1L<<8) |
| |
| /* Set if the type object is dynamically allocated */ |
| #define Py_TPFLAGS_HEAPTYPE (1L<<9) |
| |
| /* Set if the type allows subclassing */ |
| #define Py_TPFLAGS_BASETYPE (1L<<10) |
| |
| /* Set if the type is 'ready' -- fully initialized */ |
| #define Py_TPFLAGS_READY (1L<<12) |
| |
| /* Set while the type is being 'readied', to prevent recursive ready calls */ |
| #define Py_TPFLAGS_READYING (1L<<13) |
| |
| /* Objects support garbage collection (see objimp.h) */ |
| #define Py_TPFLAGS_HAVE_GC (1L<<14) |
| |
| /* These two bits are preserved for Stackless Python, next after this is 16 */ |
| #ifdef STACKLESS |
| #define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION (3L<<15) |
| #else |
| #define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION 0 |
| #endif |
| |
| #define Py_TPFLAGS_DEFAULT ( \ |
| Py_TPFLAGS_HAVE_GETCHARBUFFER | \ |
| Py_TPFLAGS_HAVE_SEQUENCE_IN | \ |
| Py_TPFLAGS_HAVE_INPLACEOPS | \ |
| Py_TPFLAGS_HAVE_RICHCOMPARE | \ |
| Py_TPFLAGS_HAVE_WEAKREFS | \ |
| Py_TPFLAGS_HAVE_ITER | \ |
| Py_TPFLAGS_HAVE_CLASS | \ |
| Py_TPFLAGS_HAVE_STACKLESS_EXTENSION | \ |
| 0) |
| |
| #define PyType_HasFeature(t,f) (((t)->tp_flags & (f)) != 0) |
| |
| |
| /* |
| 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 |
| NIL pointer. If it may be NIL, 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.) |
| |
| *** WARNING*** The Py_DECREF macro must have a side-effect-free argument |
| since it may evaluate its argument multiple times. (The alternative |
| would be to mace it a proper function or assign it to a global temporary |
| variable first, both of which are slower; and in a multi-threaded |
| environment the global variable trick is not safe.) |
| */ |
| |
| /* First define a pile of simple helper macros, one set per special |
| * build symbol. These either expand to the obvious things, or to |
| * nothing at all when the special mode isn't in effect. The main |
| * macros can later be defined just once then, yet expand to different |
| * things depending on which special build options are and aren't in effect. |
| * Trust me <wink>: while painful, this is 20x easier to understand than, |
| * e.g, defining _Py_NewReference five different times in a maze of nested |
| * #ifdefs (we used to do that -- it was impenetrable). |
| */ |
| #ifdef Py_REF_DEBUG |
| PyAPI_DATA(long) _Py_RefTotal; |
| PyAPI_FUNC(void) _Py_NegativeRefcount(const char *fname, |
| int lineno, PyObject *op); |
| #define _Py_INC_REFTOTAL _Py_RefTotal++ |
| #define _Py_DEC_REFTOTAL _Py_RefTotal-- |
| #define _Py_REF_DEBUG_COMMA , |
| #define _Py_CHECK_REFCNT(OP) \ |
| { if ((OP)->ob_refcnt < 0) \ |
| _Py_NegativeRefcount(__FILE__, __LINE__, \ |
| (PyObject *)(OP)); \ |
| } |
| #else |
| #define _Py_INC_REFTOTAL |
| #define _Py_DEC_REFTOTAL |
| #define _Py_REF_DEBUG_COMMA |
| #define _Py_CHECK_REFCNT(OP) /* a semicolon */; |
| #endif /* Py_REF_DEBUG */ |
| |
| #ifdef COUNT_ALLOCS |
| PyAPI_FUNC(void) inc_count(PyTypeObject *); |
| #define _Py_INC_TPALLOCS(OP) inc_count((OP)->ob_type) |
| #define _Py_INC_TPFREES(OP) (OP)->ob_type->tp_frees++ |
| #define _Py_DEC_TPFREES(OP) (OP)->ob_type->tp_frees-- |
| #define _Py_COUNT_ALLOCS_COMMA , |
| #else |
| #define _Py_INC_TPALLOCS(OP) |
| #define _Py_INC_TPFREES(OP) |
| #define _Py_DEC_TPFREES(OP) |
| #define _Py_COUNT_ALLOCS_COMMA |
| #endif /* COUNT_ALLOCS */ |
| |
| #ifdef Py_TRACE_REFS |
| /* Py_TRACE_REFS is such major surgery that we call external routines. */ |
| PyAPI_FUNC(void) _Py_NewReference(PyObject *); |
| PyAPI_FUNC(void) _Py_ForgetReference(PyObject *); |
| PyAPI_FUNC(void) _Py_Dealloc(PyObject *); |
| PyAPI_FUNC(void) _Py_PrintReferences(FILE *); |
| PyAPI_FUNC(void) _Py_PrintReferenceAddresses(FILE *); |
| PyAPI_FUNC(void) _Py_AddToAllObjects(PyObject *, int force); |
| |
| #else |
| /* Without Py_TRACE_REFS, there's little enough to do that we expand code |
| * inline. |
| */ |
| #define _Py_NewReference(op) ( \ |
| _Py_INC_TPALLOCS(op) _Py_COUNT_ALLOCS_COMMA \ |
| _Py_INC_REFTOTAL _Py_REF_DEBUG_COMMA \ |
| (op)->ob_refcnt = 1) |
| |
| #define _Py_ForgetReference(op) _Py_INC_TPFREES(op) |
| |
| #define _Py_Dealloc(op) ( \ |
| _Py_INC_TPFREES(op) _Py_COUNT_ALLOCS_COMMA \ |
| (*(op)->ob_type->tp_dealloc)((PyObject *)(op))) |
| #endif /* !Py_TRACE_REFS */ |
| |
| #define Py_INCREF(op) ( \ |
| _Py_INC_REFTOTAL _Py_REF_DEBUG_COMMA \ |
| (op)->ob_refcnt++) |
| |
| #define Py_DECREF(op) \ |
| if (_Py_DEC_REFTOTAL _Py_REF_DEBUG_COMMA \ |
| --(op)->ob_refcnt != 0) \ |
| _Py_CHECK_REFCNT(op) \ |
| else \ |
| _Py_Dealloc((PyObject *)(op)) |
| |
| #define Py_CLEAR(op) \ |
| do { \ |
| if (op) { \ |
| PyObject *tmp = (PyObject *)(op); \ |
| (op) = NULL; \ |
| Py_DECREF(tmp); \ |
| } \ |
| } while (0) |
| |
| /* Macros to use in case the object pointer may be NULL: */ |
| #define Py_XINCREF(op) if ((op) == NULL) ; else Py_INCREF(op) |
| #define Py_XDECREF(op) if ((op) == NULL) ; else Py_DECREF(op) |
| |
| /* |
| 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 *); |
| |
| /* |
| _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'). |
| |
| Don't forget to apply Py_INCREF() when returning this value!!! |
| */ |
| PyAPI_DATA(PyObject) _Py_NoneStruct; /* Don't use this directly */ |
| #define Py_None (&_Py_NoneStruct) |
| |
| /* Macro for returning Py_None from a function */ |
| #define Py_RETURN_NONE return Py_INCREF(Py_None), Py_None |
| |
| /* |
| 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 */ |
| #define Py_NotImplemented (&_Py_NotImplementedStruct) |
| |
| /* Rich comparison opcodes */ |
| #define Py_LT 0 |
| #define Py_LE 1 |
| #define Py_EQ 2 |
| #define Py_NE 3 |
| #define Py_GT 4 |
| #define Py_GE 5 |
| |
| /* Maps Py_LT to Py_GT, ..., Py_GE to Py_LE. |
| * Defined in object.c. |
| */ |
| PyAPI_DATA(int) _Py_SwappedOp[]; |
| |
| /* |
| Define staticforward and statichere for source compatibility with old |
| C extensions. |
| |
| The staticforward define was needed to support certain broken C |
| compilers (notably SCO ODT 3.0, perhaps early AIX as well) botched the |
| static keyword when it was used with a forward declaration of a static |
| initialized structure. Standard C allows the forward declaration with |
| static, and we've decided to stop catering to broken C compilers. |
| (In fact, we expect that the compilers are all fixed eight years later.) |
| */ |
| |
| #define staticforward static |
| #define statichere static |
| |
| |
| /* |
| 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. |
| */ |
| |
| |
| /* Trashcan mechanism, thanks to Christian Tismer. |
| |
| When deallocating a container object, it's possible to trigger an unbounded |
| chain of deallocations, as each Py_DECREF in turn drops the refcount on "the |
| next" object in the chain to 0. This can easily lead to stack faults, and |
| especially in threads (which typically have less stack space to work with). |
| |
| A container object that participates in cyclic gc can avoid this by |
| bracketing the body of its tp_dealloc function with a pair of macros: |
| |
| static void |
| mytype_dealloc(mytype *p) |
| { |
| ... declarations go here ... |
| |
| PyObject_GC_UnTrack(p); // must untrack first |
| Py_TRASHCAN_SAFE_BEGIN(p) |
| ... The body of the deallocator goes here, including all calls ... |
| ... to Py_DECREF on contained objects. ... |
| Py_TRASHCAN_SAFE_END(p) |
| } |
| |
| CAUTION: Never return from the middle of the body! If the body needs to |
| "get out early", put a label immediately before the Py_TRASHCAN_SAFE_END |
| call, and goto it. Else the call-depth counter (see below) will stay |
| above 0 forever, and the trashcan will never get emptied. |
| |
| How it works: The BEGIN macro increments a call-depth counter. So long |
| as this counter is small, the body of the deallocator is run directly without |
| further ado. But if the counter gets large, it instead adds p to a list of |
| objects to be deallocated later, skips the body of the deallocator, and |
| resumes execution after the END macro. The tp_dealloc routine then returns |
| without deallocating anything (and so unbounded call-stack depth is avoided). |
| |
| When the call stack finishes unwinding again, code generated by the END macro |
| notices this, and calls another routine to deallocate all the objects that |
| may have been added to the list of deferred deallocations. In effect, a |
| chain of N deallocations is broken into N / PyTrash_UNWIND_LEVEL pieces, |
| with the call stack never exceeding a depth of PyTrash_UNWIND_LEVEL. |
| */ |
| |
| PyAPI_FUNC(void) _PyTrash_deposit_object(PyObject*); |
| PyAPI_FUNC(void) _PyTrash_destroy_chain(void); |
| PyAPI_DATA(int) _PyTrash_delete_nesting; |
| PyAPI_DATA(PyObject *) _PyTrash_delete_later; |
| |
| #define PyTrash_UNWIND_LEVEL 50 |
| |
| #define Py_TRASHCAN_SAFE_BEGIN(op) \ |
| if (_PyTrash_delete_nesting < PyTrash_UNWIND_LEVEL) { \ |
| ++_PyTrash_delete_nesting; |
| /* The body of the deallocator is here. */ |
| #define Py_TRASHCAN_SAFE_END(op) \ |
| --_PyTrash_delete_nesting; \ |
| if (_PyTrash_delete_later && _PyTrash_delete_nesting <= 0) \ |
| _PyTrash_destroy_chain(); \ |
| } \ |
| else \ |
| _PyTrash_deposit_object((PyObject*)op); |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| #endif /* !Py_OBJECT_H */ |