source: trunk/essentials/dev-lang/python/Include/object.h@ 3310

#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            \
        Py_ssize_t 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                   \
        Py_ssize_t ob_size; /* Number of items in variable part */
#define Py_INVALID_SIZE (Py_ssize_t)-1

/* 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 Py_ssize_t (*lenfunc)(PyObject *);
typedef int (*coercion)(PyObject **, PyObject **);
typedef PyObject *(*intargfunc)(PyObject *, int) Py_DEPRECATED(2.5);
typedef PyObject *(*intintargfunc)(PyObject *, int, int) Py_DEPRECATED(2.5);
typedef PyObject *(*ssizeargfunc)(PyObject *, Py_ssize_t);
typedef PyObject *(*ssizessizeargfunc)(PyObject *, Py_ssize_t, Py_ssize_t);
typedef int(*intobjargproc)(PyObject *, int, PyObject *);
typedef int(*intintobjargproc)(PyObject *, int, int, PyObject *);
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 *);

/* int-based buffer interface */
typedef int (*getreadbufferproc)(PyObject *, int, void **);
typedef int (*getwritebufferproc)(PyObject *, int, void **);
typedef int (*getsegcountproc)(PyObject *, int *);
typedef int (*getcharbufferproc)(PyObject *, int, char **);
/* ssize_t-based buffer interface */
typedef Py_ssize_t (*readbufferproc)(PyObject *, Py_ssize_t, void **);
typedef Py_ssize_t (*writebufferproc)(PyObject *, Py_ssize_t, void **);
typedef Py_ssize_t (*segcountproc)(PyObject *, Py_ssize_t *);
typedef Py_ssize_t (*charbufferproc)(PyObject *, Py_ssize_t, 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;

        /* Added in release 2.5 */
        unaryfunc nb_index;
} PyNumberMethods;

typedef struct {
        lenfunc sq_length;
        binaryfunc sq_concat;
        ssizeargfunc sq_repeat;
        ssizeargfunc sq_item;
        ssizessizeargfunc sq_slice;
        ssizeobjargproc sq_ass_item;
        ssizessizeobjargproc sq_ass_slice;
        objobjproc sq_contains;
        /* Added in release 2.0 */
        binaryfunc sq_inplace_concat;
        ssizeargfunc sq_inplace_repeat;
} PySequenceMethods;

typedef struct {
        lenfunc mp_length;
        binaryfunc mp_subscript;
        objobjargproc mp_ass_subscript;
} PyMappingMethods;

typedef struct {
        readbufferproc bf_getreadbuffer;
        writebufferproc bf_getwritebuffer;
        segcountproc bf_getsegcount;
        charbufferproc 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 *, Py_ssize_t);

typedef struct _typeobject {
        PyObject_VAR_HEAD
        const char *tp_name; /* For printing, in format "<module>.<name>" */
        Py_ssize_t 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;

        const 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 */
        Py_ssize_t 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;
        Py_ssize_t 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 */
        Py_ssize_t tp_allocs;
        Py_ssize_t tp_frees;
        Py_ssize_t tp_maxalloc;
        struct _typeobject *tp_prev;
        struct _typeobject *tp_next;
#endif
} PyTypeObject;