Objects/cobject.c

   1
   2 /* Wrap void* pointers to be passed between C modules */
   3
   4 #include "Python.h"
   5
   6
   7 /* Declarations for objects of type PyCObject */
   8
   9 typedef void (*destructor1)(void *);
  10 typedef void (*destructor2)(void *, void*);
  11
  12 typedef struct {
  13     PyObject_HEAD
  14     void *cobject;
  15     void *desc;
  16     void (*destructor)(void *);
  17 } PyCObject;
  18
  19 PyObject *
  20 PyCObject_FromVoidPtr(void *cobj, void (*destr)(void *))
  21 {
  22     PyCObject *self;
  23
  24     self = PyObject_NEW(PyCObject, &PyCObject_Type);
  25     if (self == NULL)
  26         return NULL;
  27     self->cobject=cobj;
  28     self->destructor=destr;
  29     self->desc=NULL;
  30
  31     return (PyObject *)self;
  32 }
  33
  34 PyObject *
  35 PyCObject_FromVoidPtrAndDesc(void *cobj, void *desc,
  36                              void (*destr)(void *, void *))
  37 {
  38     PyCObject *self;
  39
  40     if (!desc) {
  41         PyErr_SetString(PyExc_TypeError,
  42                         "PyCObject_FromVoidPtrAndDesc called with null"
  43                         " description");
  44         return NULL;
  45     }
  46     self = PyObject_NEW(PyCObject, &PyCObject_Type);
  47     if (self == NULL)
  48         return NULL;
  49     self->cobject = cobj;
  50     self->destructor = (destructor1)destr;
  51     self->desc = desc;
  52
  53     return (PyObject *)self;
  54 }
  55
  56 void *
  57 PyCObject_AsVoidPtr(PyObject *self)
  58 {
  59     if (self) {
  60         if (self->ob_type == &PyCObject_Type)
  61             return ((PyCObject *)self)->cobject;
  62         PyErr_SetString(PyExc_TypeError,
  63                         "PyCObject_AsVoidPtr with non-C-object");
  64     }
  65     if (!PyErr_Occurred())
  66         PyErr_SetString(PyExc_TypeError,
  67                         "PyCObject_AsVoidPtr called with null pointer");
  68     return NULL;
  69 }
  70
  71 void *
  72 PyCObject_GetDesc(PyObject *self)
  73 {
  74     if (self) {
  75         if (self->ob_type == &PyCObject_Type)
  76             return ((PyCObject *)self)->desc;
  77         PyErr_SetString(PyExc_TypeError,
  78                         "PyCObject_GetDesc with non-C-object");
  79     }
  80     if (!PyErr_Occurred())
  81         PyErr_SetString(PyExc_TypeError,
  82                         "PyCObject_GetDesc called with null pointer");
  83     return NULL;
  84 }
  85
  86 void *
  87 PyCObject_Import(char *module_name, char *name)
  88 {
  89     PyObject *m, *c;
  90     void *r = NULL;
  91
  92     if ((m = PyImport_ImportModule(module_name))) {
  93         if ((c = PyObject_GetAttrString(m,name))) {
  94             r = PyCObject_AsVoidPtr(c);
  95             Py_DECREF(c);
  96         }
  97         Py_DECREF(m);
  98     }
  99     return r;
 100 }
 101
 102 int
 103 PyCObject_SetVoidPtr(PyObject *self, void *cobj)
 104 {
 105     PyCObject* cself = (PyCObject*)self;
 106     if (cself == NULL || !PyCObject_Check(cself) ||
 107         cself->destructor != NULL) {
 108         PyErr_SetString(PyExc_TypeError,
 109                         "Invalid call to PyCObject_SetVoidPtr");
 110         return 0;
 111     }
 112     cself->cobject = cobj;
 113     return 1;
 114 }
 115
 116 static void
 117 PyCObject_dealloc(PyCObject *self)
 118 {
 119     if (self->destructor) {
 120         if(self->desc)
 121             ((destructor2)(self->destructor))(self->cobject, self->desc);
 122         else
 123             (self->destructor)(self->cobject);
 124     }
 125     PyObject_DEL(self);
 126 }
 127
 128
 129 PyDoc_STRVAR(PyCObject_Type__doc__,
 130 "C objects to be exported from one extension module to another\n\
 131 \n\
 132 C objects are used for communication between extension modules.  They\n\
 133 provide a way for an extension module to export a C interface to other\n\
 134 extension modules, so that extension modules can use the Python import\n\
 135 mechanism to link to one another.");
 136
 137 PyTypeObject PyCObject_Type = {
 138     PyVarObject_HEAD_INIT(&PyType_Type, 0)
 139     "PyCObject",                /*tp_name*/
 140     sizeof(PyCObject),          /*tp_basicsize*/
 141     0,                          /*tp_itemsize*/
 142     /* methods */
 143     (destructor)PyCObject_dealloc, /*tp_dealloc*/
 144     0,                          /*tp_print*/
 145     0,                          /*tp_getattr*/
 146     0,                          /*tp_setattr*/
 147     0,                          /*tp_compare*/
 148     0,                          /*tp_repr*/
 149     0,                          /*tp_as_number*/
 150     0,                          /*tp_as_sequence*/
 151     0,                          /*tp_as_mapping*/
 152     0,                          /*tp_hash*/
 153     0,                          /*tp_call*/
 154     0,                          /*tp_str*/
 155     0,                          /*tp_getattro*/
 156     0,                          /*tp_setattro*/
 157     0,                          /*tp_as_buffer*/
 158     0,                          /*tp_flags*/
 159     PyCObject_Type__doc__       /*tp_doc*/
 160 };