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     {
  85       unicode_str = obj;
  86       Py_INCREF (obj);
  87     }
  88
  89   else if (PyString_Check (obj))
  90     unicode_str = PyUnicode_FromEncodedObject (obj, host_charset (), NULL);
  91   else
  92     {
  93       PyErr_SetString (PyExc_TypeError,
  94                        _("Expected a string or unicode object."));
  95       unicode_str = NULL;
  96     }
  97
  98   return unicode_str;
  99 }
 100
 101 /* Returns a newly allocated string with the contents of the given unicode
 102    string object converted to CHARSET.  If an error occurs during the
 103    conversion, NULL will be returned and a python exception will be set.
 104
 105    The caller is responsible for xfree'ing the string.  */
 106 static char *
 107 unicode_to_encoded_string (PyObject *unicode_str, const char *charset)
 108 {
 109   char *result;
 110   PyObject *string;
 111
 112   /* Translate string to named charset.  */
 113   string = PyUnicode_AsEncodedString (unicode_str, charset, NULL);
 114   if (string == NULL)
 115     return NULL;
 116
 117   result = xstrdup (PyString_AsString (string));
 118
 119   Py_DECREF (string);
 120
 121   return result;
 122 }
 123
 124 /* Returns a newly allocated string with the contents of the given unicode
 125    string object converted to the target's charset.  If an error occurs during
 126    the conversion, NULL will be returned and a python exception will be set.
 127
 128    The caller is responsible for xfree'ing the string.  */
 129 char *
 130 unicode_to_target_string (PyObject *unicode_str)
 131 {
 132   return unicode_to_encoded_string (unicode_str, target_charset ());
 133 }
 134
 135 /* Converts a python string (8-bit or unicode) to a target string in
 136    the target's charset.  Returns NULL on error, with a python exception set.
 137
 138    The caller is responsible for xfree'ing the string.  */
 139 char *
 140 python_string_to_target_string (PyObject *obj)
 141 {
 142   PyObject *str;
 143   char *result;
 144
 145   str = python_string_to_unicode (obj);
 146   if (str == NULL)
 147     return NULL;
 148
 149   result = unicode_to_target_string (str);
 150   Py_DECREF (str);
 151   return result;
 152 }
 153
 154 /* Converts a python string (8-bit or unicode) to a target string in
 155    the host's charset.  Returns NULL on error, with a python exception set.
 156
 157    The caller is responsible for xfree'ing the string.  */
 158 char *
 159 python_string_to_host_string (PyObject *obj)
 160 {
 161   PyObject *str;
 162   char *result;
 163
 164   str = python_string_to_unicode (obj);
 165   if (str == NULL)
 166     return NULL;
 167
 168   result = unicode_to_encoded_string (str, host_charset ());
 169   Py_DECREF (str);
 170   return result;
 171 }
 172
 173 /* Converts a target string of LENGTH bytes in the target's charset to a
 174    Python Unicode string. If LENGTH is -1, convert until a null byte is found.
 175
 176    Returns NULL on error, with a python exception set.  */
 177 PyObject *
 178 target_string_to_unicode (const gdb_byte *str, int length)
 179 {
 180   if (length == -1)
 181     length = strlen (str);
 182
 183   return PyUnicode_Decode (str, length, target_charset (), NULL);
 184 }
 185
 186 /* Return true if OBJ is a Python string or unicode object, false
 187    otherwise.  */
 188
 189 int
 190 gdbpy_is_string (PyObject *obj)
 191 {
 192   return PyString_Check (obj) || PyUnicode_Check (obj);
 193 }