Objects/cobject.c

/***********************************************************
Copyright (c) 2000, BeOpen.com.
Copyright (c) 1995-2000, Corporation for National Research Initiatives.
Copyright (c) 1990-1995, Stichting Mathematisch Centrum.
All rights reserved.

See the file "Misc/COPYRIGHT" for information on usage and
redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES.
******************************************************************/

/* Wrap void* pointers to be passed between C modules */

#include "Python.h"


/* Declarations for objects of type PyCObject */

typedef void (*destructor1)(void *);
typedef void (*destructor2)(void *, void*);

typedef struct {
	PyObject_HEAD
	void *cobject;
        void *desc;
	void (*destructor)(void *);
} PyCObject;

PyObject *
PyCObject_FromVoidPtr(cobj, destr)
	void *cobj;
	void (*destr)(void *);
{
	PyCObject *self;
	
	self = PyObject_NEW(PyCObject, &PyCObject_Type);
	if (self == NULL)
		return NULL;
	self->cobject=cobj;
	self->destructor=destr;
	self->desc=NULL;
	return (PyObject *)self;
}

PyObject *
PyCObject_FromVoidPtrAndDesc(cobj, desc, destr)
	void *cobj;
	void *desc;
	void (*destr)(void *, void *);
{
	PyCObject *self;

	if(!desc) {
	        PyErr_SetString(PyExc_TypeError,
		  "PyCObject_FromVoidPtrAndDesc called with null description");
		return NULL;
	}
	
	self = PyObject_NEW(PyCObject, &PyCObject_Type);
	if (self == NULL)
		return NULL;
	self->cobject=cobj;
	self->destructor=(destructor1)destr;
	self->desc=desc;
	return (PyObject *)self;
}

void *
PyCObject_AsVoidPtr(self)
	PyObject *self;
{
        if(self)
	  {
	    if(self->ob_type == &PyCObject_Type)
	      return ((PyCObject *)self)->cobject;
	    PyErr_SetString(PyExc_TypeError,
			    "PyCObject_AsVoidPtr with non-C-object");
	  }
	if(! PyErr_Occurred())
	    PyErr_SetString(PyExc_TypeError,
			    "PyCObject_AsVoidPtr called with null pointer");
	return NULL;
}

void *
PyCObject_GetDesc(self)
	PyObject *self;
{
        if(self)
	  {
	    if(self->ob_type == &PyCObject_Type)
	      return ((PyCObject *)self)->desc;
	    PyErr_SetString(PyExc_TypeError,
			    "PyCObject_GetDesc with non-C-object");
	  }
	if(! PyErr_Occurred())
	    PyErr_SetString(PyExc_TypeError,
			    "PyCObject_GetDesc called with null pointer");
	return NULL;
}

void *
PyCObject_Import(module_name, name)
     char *module_name;
     char *name;
{
  PyObject *m, *c;
  void *r=NULL;
  
  if((m=PyImport_ImportModule(module_name)))
    {
      if((c=PyObject_GetAttrString(m,name)))
	{
	  r=PyCObject_AsVoidPtr(c);
	  Py_DECREF(c);
	}
      Py_DECREF(m);
    }

  return r;
}

static void
PyCObject_dealloc(self)
	PyCObject *self;
{
        if(self->destructor)
	  {
	    if(self->desc)
	          ((destructor2)(self->destructor))(self->cobject, self->desc);
	    else
	          (self->destructor)(self->cobject);
	  }
	PyObject_DEL(self);
}


static char PyCObject_Type__doc__[] = 
"C objects to be exported from one extension module to another\n\
\n\
C objects are used for communication between extension modules.  They\n\
provide a way for an extension module to export a C interface to other\n\
extension modules, so that extension modules can use the Python import\n\
mechanism to link to one another.\n"
;

PyTypeObject PyCObject_Type = {
	PyObject_HEAD_INIT(&PyType_Type)
	0,				/*ob_size*/
	"PyCObject",			/*tp_name*/
	sizeof(PyCObject),		/*tp_basicsize*/
	0,				/*tp_itemsize*/
	/* methods */
	(destructor)PyCObject_dealloc,	/*tp_dealloc*/
	(printfunc)0,		/*tp_print*/
	(getattrfunc)0,	/*tp_getattr*/
	(setattrfunc)0,	/*tp_setattr*/
	(cmpfunc)0,		/*tp_compare*/
	(reprfunc)0,		/*tp_repr*/
	0,			/*tp_as_number*/
	0,		/*tp_as_sequence*/
	0,		/*tp_as_mapping*/
	(hashfunc)0,		/*tp_hash*/
	(ternaryfunc)0,		/*tp_call*/
	(reprfunc)0,		/*tp_str*/

	/* Space for future expansion */
	0L,0L,0L,0L,
	PyCObject_Type__doc__ /* Documentation string */
};