plugins/python/helpers.c

   1 /* nbdkit
   2  * Copyright Red Hat
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  * * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * * Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  *
  15  * * Neither the name of Red Hat nor the names of its contributors may be
  16  * used to endorse or promote products derived from this software without
  17  * specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  22  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  26  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  27  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  29  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <config.h>
  34
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37
  38 #include "plugin.h"
  39
  40 /* Is a callback defined? */
  41 int
  42 callback_defined (const char *name, PyObject **obj_rtn)
  43 {
  44   PyObject *obj;
  45
  46   assert (script != NULL);
  47   assert (module != NULL);
  48
  49   obj = PyObject_GetAttrString (module, name);
  50   if (!obj) {
  51     PyErr_Clear (); /* Clear the AttributeError from testing attr. */
  52     return 0;
  53   }
  54   if (!PyCallable_Check (obj)) {
  55     nbdkit_debug ("object %s isn't callable", name);
  56     Py_DECREF (obj);
  57     return 0;
  58   }
  59
  60   if (obj_rtn != NULL)
  61     *obj_rtn = obj;
  62   else
  63     Py_DECREF (obj);
  64
  65   return 1;
  66 }
  67
  68 /* Convert bytes/str/unicode into a string.  Caller must free. */
  69 char *
  70 python_to_string (PyObject *str)
  71 {
  72   if (str) {
  73     if (PyUnicode_Check (str))
  74       return strdup (PyUnicode_AsUTF8 (str));
  75     else if (PyBytes_Check (str))
  76       return strdup (PyBytes_AS_STRING (str));
  77   }
  78   return NULL;
  79 }