gdb/python/python-utils.c

   1 /* General utility routines for GDB/Python.
   2
   3    Copyright (C) 2008, 2009 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "charset.h"
  22 #include "python-internal.h"
  23
  24
  25 /* This is a cleanup function which decrements the refcount on a
  26    Python object.  */
  27
  28 static void
  29 py_decref (void *p)
  30 {
  31   PyObject *py = p;
  32   /* Note that we need the extra braces in this 'if' to avoid a
  33      warning from gcc.  */
  34   if (py)
  35     {
  36       Py_DECREF (py);
  37     }
  38 }
  39
  40 /* Return a new cleanup which will decrement the Python object's
  41    refcount when run.  */
  42
  43 struct cleanup *
  44 make_cleanup_py_decref (PyObject *py)
  45 {
  46   return make_cleanup (py_decref, (void *) py);
  47 }
  48
  49 /* A cleanup function to restore the thread state.  */
  50
  51 static void
  52 py_gil_restore (void *p)
  53 {
  54   PyGILState_STATE *state = p;
  55   PyGILState_Release (*state);
  56 }
  57
  58 /* Return a new cleanup which will restore the Python GIL state.  */
  59
  60 struct cleanup *
  61 make_cleanup_py_restore_gil (PyGILState_STATE *state)
  62 {
  63   return make_cleanup (py_gil_restore, state);
  64 }
  65
  66 /* Converts a Python 8-bit string to a unicode string object.  Assumes the
  67    8-bit string is in the host charset.  If an error occurs during conversion,
  68    returns NULL with a python exception set.
  69
  70    As an added bonus, the functions accepts a unicode string and returns it
  71    right away, so callers don't need to check which kind of string they've
  72    got.
  73
  74    If the given object is not one of the mentioned string types, NULL is
  75    returned, with the TypeError python exception set.  */
  76 PyObject *
  77 python_string_to_unicode (PyObject *obj)
  78 {
  79   PyObject *unicode_str;
  80
  81   /* If obj is already a unicode string, just return it.
  82      I wish life was always that simple...  */
  83   if (PyUnicode_Check (obj))
  84     unicode_str = obj;
  85   else if (PyString_Check (obj))
  86     unicode_str = PyUnicode_FromEncodedObject (obj, host_charset (), NULL);
  87   else
  88     {
  89       PyErr_SetString (PyExc_TypeError,
  90                        _("Expected a string or unicode object."));
  91       unicode_str = NULL;
  92     }
  93
  94   return unicode_str;
  95 }
  96
  97 /* Returns a newly allocated string with the contents of the given unicode
  98    string object converted to CHARSET.  If an error occurs during the
  99    conversion, NULL will be returned and a python exception will be set.
 100
 101    The caller is responsible for xfree'ing the string.  */
 102 static char *
 103 unicode_to_encoded_string (PyObject *unicode_str, const char *charset)
 104 {
 105   char *result;
 106   PyObject *string;
 107
 108   /* Translate string to named charset.  */
 109   string = PyUnicode_AsEncodedString (unicode_str, charset, NULL);
 110   if (string == NULL)
 111     return NULL;
 112
 113   result = xstrdup (PyString_AsString (string));
 114
 115   Py_DECREF (string);
 116
 117   return result;
 118 }
 119
 120 /* Returns a newly allocated string with the contents of the given unicode
 121    string object converted to the target's charset.  If an error occurs during
 122    the conversion, NULL will be returned and a python exception will be set.
 123
 124    The caller is responsible for xfree'ing the string.  */
 125 char *
 126 unicode_to_target_string (PyObject *unicode_str)
 127 {
 128   return unicode_to_encoded_string (unicode_str, target_charset ());
 129 }
 130
 131 /* Converts a python string (8-bit or unicode) to a target string in
 132    the target's charset.  Returns NULL on error, with a python exception set.
 133
 134    The caller is responsible for xfree'ing the string.  */
 135 char *
 136 python_string_to_target_string (PyObject *obj)
 137 {
 138   PyObject *str;
 139
 140   str = python_string_to_unicode (obj);
 141   if (str == NULL)
 142     return NULL;
 143
 144   return unicode_to_target_string (str);
 145 }
 146
 147 /* Converts a python string (8-bit or unicode) to a target string in
 148    the host's charset.  Returns NULL on error, with a python exception set.
 149
 150    The caller is responsible for xfree'ing the string.  */
 151 char *
 152 python_string_to_host_string (PyObject *obj)
 153 {
 154   PyObject *str;
 155
 156   str = python_string_to_unicode (obj);
 157   if (str == NULL)
 158     return NULL;
 159
 160   return unicode_to_encoded_string (str, host_charset ());
 161 }
 162
 163 /* Converts a target string of LENGTH bytes in the target's charset to a
 164    Python Unicode string. If LENGTH is -1, convert until a null byte is found.
 165
 166    Returns NULL on error, with a python exception set.  */
 167 PyObject *
 168 target_string_to_unicode (const gdb_byte *str, int length)
 169 {
 170   if (length == -1)
 171     length = strlen (str);
 172
 173   return PyUnicode_Decode (str, length, target_charset (), NULL);
 174 }
 175
 176 /* Return true if OBJ is a Python string or unicode object, false
 177    otherwise.  */
 178
 179 int
 180 gdbpy_is_string (PyObject *obj)
 181 {
 182   return PyString_Check (obj) || PyUnicode_Check (obj);
 183 }