gdb/python/py-function.c

   1 /* Convenience functions implemented in Python.
   2
   3    Copyright (C) 2008-2019 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
  21 #include "defs.h"
  22 #include "value.h"
  23 #include "python-internal.h"
  24 #include "charset.h"
  25 #include "gdbcmd.h"
  26 #include "cli/cli-decode.h"
  27 #include "completer.h"
  28 #include "expression.h"
  29 #include "language.h"
  30 #include "py-ref.h"
  31
  32 extern PyTypeObject fnpy_object_type
  33     CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("PyObject");
  34
  35 \f
  36
  37 /* Return a reference to a tuple ARGC elements long.  Each element of the
  38    tuple is a PyObject converted from the corresponding element of ARGV.  */
  39
  40 static gdbpy_ref<>
  41 convert_values_to_python (int argc, struct value **argv)
  42 {
  43   int i;
  44   gdbpy_ref<> result (PyTuple_New (argc));
  45
  46   if (result == NULL)
  47     return NULL;
  48
  49   for (i = 0; i < argc; ++i)
  50     {
  51       gdbpy_ref<> elt (value_to_value_object (argv[i]));
  52       if (elt == NULL)
  53         return NULL;
  54       PyTuple_SetItem (result.get (), i, elt.release ());
  55     }
  56   return result;
  57 }
  58
  59 /* Call a Python function object's invoke method.  */
  60
  61 static struct value *
  62 fnpy_call (struct gdbarch *gdbarch, const struct language_defn *language,
  63            void *cookie, int argc, struct value **argv)
  64 {
  65   /* The gdbpy_enter object needs to be placed first, so that it's the last to
  66      be destroyed.  */
  67   gdbpy_enter enter_py (gdbarch, language);
  68   struct value *value;
  69   gdbpy_ref<> result;
  70   gdbpy_ref<> args = convert_values_to_python (argc, argv);
  71
  72   /* convert_values_to_python can return NULL on error.  If we
  73      encounter this, do not call the function, but allow the Python ->
  74      error code conversion below to deal with the Python exception.
  75      Note, that this is different if the function simply does not
  76      have arguments.  */
  77
  78   if (args != NULL)
  79     {
  80       gdbpy_ref<> callable (PyObject_GetAttrString ((PyObject *) cookie,
  81                                                     "invoke"));
  82       if (callable == NULL)
  83         error (_("No method named 'invoke' in object."));
  84
  85       result.reset (PyObject_Call (callable.get (), args.get (), NULL));
  86     }
  87
  88   if (result == NULL)
  89     gdbpy_handle_exception ();
  90
  91   value = convert_value_from_python (result.get ());
  92   if (value == NULL)
  93     {
  94       gdbpy_print_stack ();
  95       error (_("Error while executing Python code."));
  96     }
  97
  98   return value;
  99 }
 100
 101 /* Initializer for a Function object.  It takes one argument, the name
 102    of the function.  */
 103
 104 static int
 105 fnpy_init (PyObject *self, PyObject *args, PyObject *kwds)
 106 {
 107   const char *name;
 108   gdb::unique_xmalloc_ptr<char> docstring;
 109
 110   if (! PyArg_ParseTuple (args, "s", &name))
 111     return -1;
 112   Py_INCREF (self);
 113
 114   if (PyObject_HasAttrString (self, "__doc__"))
 115     {
 116       gdbpy_ref<> ds_obj (PyObject_GetAttrString (self, "__doc__"));
 117       if (ds_obj != NULL)
 118         {
 119           if (gdbpy_is_string (ds_obj.get ()))
 120             {
 121               docstring = python_string_to_host_string (ds_obj.get ());
 122               if (docstring == NULL)
 123                 {
 124                   Py_DECREF (self);
 125                   return -1;
 126                 }
 127             }
 128         }
 129     }
 130   if (! docstring)
 131     docstring.reset (xstrdup (_("This function is not documented.")));
 132
 133   add_internal_function (name, docstring.release (), fnpy_call, self);
 134   return 0;
 135 }
 136
 137 /* Initialize internal function support.  */
 138
 139 int
 140 gdbpy_initialize_functions (void)
 141 {
 142   fnpy_object_type.tp_new = PyType_GenericNew;
 143   if (PyType_Ready (&fnpy_object_type) < 0)
 144     return -1;
 145
 146   return gdb_pymodule_addobject (gdb_module, "Function",
 147                                  (PyObject *) &fnpy_object_type);
 148 }
 149
 150 \f
 151
 152 PyTypeObject fnpy_object_type =
 153 {
 154   PyVarObject_HEAD_INIT (NULL, 0)
 155   "gdb.Function",                 /*tp_name*/
 156   sizeof (PyObject),              /*tp_basicsize*/
 157   0,                              /*tp_itemsize*/
 158   0,                              /*tp_dealloc*/
 159   0,                              /*tp_print*/
 160   0,                              /*tp_getattr*/
 161   0,                              /*tp_setattr*/
 162   0,                              /*tp_compare*/
 163   0,                              /*tp_repr*/
 164   0,                              /*tp_as_number*/
 165   0,                              /*tp_as_sequence*/
 166   0,                              /*tp_as_mapping*/
 167   0,                              /*tp_hash */
 168   0,                              /*tp_call*/
 169   0,                              /*tp_str*/
 170   0,                              /*tp_getattro*/
 171   0,                              /*tp_setattro*/
 172   0,                              /*tp_as_buffer*/
 173   Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /*tp_flags*/
 174   "GDB function object",          /* tp_doc */
 175   0,                              /* tp_traverse */
 176   0,                              /* tp_clear */
 177   0,                              /* tp_richcompare */
 178   0,                              /* tp_weaklistoffset */
 179   0,                              /* tp_iter */
 180   0,                              /* tp_iternext */
 181   0,                              /* tp_methods */
 182   0,                              /* tp_members */
 183   0,                              /* tp_getset */
 184   0,                              /* tp_base */
 185   0,                              /* tp_dict */
 186   0,                              /* tp_descr_get */
 187   0,                              /* tp_descr_set */
 188   0,                              /* tp_dictoffset */
 189   fnpy_init,                      /* tp_init */
 190   0,                              /* tp_alloc */
 191 };