cpython/Objects/xxobject.c

/* Use this file as a template to start implementing a new object type.
   If your objects will be called foobar, start by copying this file to
   foobarobject.c, changing all occurrences of xx to foobar and all
   occurrences of Xx by Foobar.  You will probably want to delete all
   references to 'x_attr' and add your own types of attributes
   instead.  Maybe you want to name your local variables other than
   'xp'.  If your object type is needed in other files, you'll have to
   create a file "foobarobject.h"; see intobject.h for an example. */


/* Xx objects */

#include "allobjects.h"

typedef struct {
	OB_HEAD
	object	*x_attr;	/* Attributes dictionary */
} xxobject;

extern typeobject Xxtype;	/* Really static, forward */

#define is_xxobject(v)		((v)->ob_type == &Xxtype)

static xxobject *
newxxobject(arg)
	object *arg;
{
	xxobject *xp;
	xp = NEWOBJ(xxobject, &Xxtype);
	if (xp == NULL)
		return NULL;
	xp->x_attr = NULL;
	return xp;
}

/* Xx methods */

static void
xx_dealloc(xp)
	xxobject *xp;
{
	XDECREF(xp->x_attr);
	DEL(xp);
}

static object *
xx_demo(self, args)
	xxobject *self;
	object *args;
{
	if (!getnoarg(args))
		return NULL;
	INCREF(None);
	return None;
}

static struct methodlist xx_methods[] = {
	"demo",		xx_demo,
	{NULL,		NULL}		/* sentinel */
};

static object *
xx_getattr(xp, name)
	xxobject *xp;
	char *name;
{
	if (xp->x_attr != NULL) {
		object *v = dictlookup(xp->x_attr, name);
		if (v != NULL) {
			INCREF(v);
			return v;
		}
	}
	return findmethod(xx_methods, (object *)xp, name);
}

static int
xx_setattr(xp, name, v)
	xxobject *xp;
	char *name;
	object *v;
{
	if (xp->x_attr == NULL) {
		xp->x_attr = newdictobject();
		if (xp->x_attr == NULL)
			return -1;
	}
	if (v == NULL)
		return dictremove(xp->x_attr, name);
	else
		return dictinsert(xp->x_attr, name, v);
}

static typeobject Xxtype = {
	OB_HEAD_INIT(&Typetype)
	0,			/*ob_size*/
	"xx",			/*tp_name*/
	sizeof(xxobject),	/*tp_size*/
	0,			/*tp_itemsize*/
	/* methods */
	xx_dealloc,	/*tp_dealloc*/
	0,		/*tp_print*/
	xx_getattr,	/*tp_getattr*/
	xx_setattr,	/*tp_setattr*/
	0,		/*tp_compare*/
	0,		/*tp_repr*/
};