342 lines
9.4 KiB
C
342 lines
9.4 KiB
C
/* Python interface to lazy strings.
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Copyright (C) 2010-2022 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "python-internal.h"
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#include "charset.h"
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#include "value.h"
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#include "valprint.h"
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#include "language.h"
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struct lazy_string_object {
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PyObject_HEAD
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/* Holds the address of the lazy string. */
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CORE_ADDR address;
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/* Holds the encoding that will be applied to the string
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when the string is printed by GDB. If the encoding is set
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to None then GDB will select the most appropriate
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encoding when the sting is printed. */
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char *encoding;
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/* If TYPE is an array: If the length is known, then this value is the
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array's length, otherwise it is -1.
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If TYPE is not an array: Then this value represents the string's length.
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In either case, if the value is -1 then the string will be fetched and
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encoded up to the first null of appropriate width. */
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long length;
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/* This attribute holds the type of the string.
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For example if the lazy string was created from a C "char*" then TYPE
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represents a C "char*".
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To get the type of the character in the string call
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stpy_lazy_string_elt_type.
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This is recorded as a PyObject so that we take advantage of support for
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preserving the type should its owning objfile go away. */
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PyObject *type;
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};
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extern PyTypeObject lazy_string_object_type
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CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("lazy_string_object");
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static PyObject *
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stpy_get_address (PyObject *self, void *closure)
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{
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lazy_string_object *self_string = (lazy_string_object *) self;
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return gdb_py_object_from_ulongest (self_string->address).release ();
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}
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static PyObject *
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stpy_get_encoding (PyObject *self, void *closure)
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{
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lazy_string_object *self_string = (lazy_string_object *) self;
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PyObject *result;
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/* An encoding can be set to NULL by the user, so check before
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attempting a Python FromString call. If NULL return Py_None. */
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if (self_string->encoding)
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result = PyUnicode_FromString (self_string->encoding);
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else
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{
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result = Py_None;
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Py_INCREF (result);
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}
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return result;
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}
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static PyObject *
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stpy_get_length (PyObject *self, void *closure)
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{
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lazy_string_object *self_string = (lazy_string_object *) self;
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return gdb_py_object_from_longest (self_string->length).release ();
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}
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static PyObject *
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stpy_get_type (PyObject *self, void *closure)
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{
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lazy_string_object *str_obj = (lazy_string_object *) self;
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Py_INCREF (str_obj->type);
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return str_obj->type;
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}
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static PyObject *
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stpy_convert_to_value (PyObject *self, PyObject *args)
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{
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lazy_string_object *self_string = (lazy_string_object *) self;
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struct value *val = NULL;
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if (self_string->address == 0)
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{
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PyErr_SetString (gdbpy_gdb_memory_error,
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_("Cannot create a value from NULL."));
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return NULL;
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}
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try
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{
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struct type *type = type_object_to_type (self_string->type);
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struct type *realtype;
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gdb_assert (type != NULL);
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realtype = check_typedef (type);
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switch (realtype->code ())
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{
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case TYPE_CODE_PTR:
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/* If a length is specified we need to convert this to an array
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of the specified size. */
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if (self_string->length != -1)
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{
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/* PR 20786: There's no way to specify an array of length zero.
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Record a length of [0,-1] which is how Ada does it. Anything
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we do is broken, but this is one possible solution. */
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type = lookup_array_range_type (TYPE_TARGET_TYPE (realtype),
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0, self_string->length - 1);
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val = value_at_lazy (type, self_string->address);
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}
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else
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val = value_from_pointer (type, self_string->address);
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break;
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default:
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val = value_at_lazy (type, self_string->address);
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break;
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}
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}
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catch (const gdb_exception &except)
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{
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GDB_PY_HANDLE_EXCEPTION (except);
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}
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return value_to_value_object (val);
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}
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static void
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stpy_dealloc (PyObject *self)
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{
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lazy_string_object *self_string = (lazy_string_object *) self;
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xfree (self_string->encoding);
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Py_TYPE (self)->tp_free (self);
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}
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/* Low level routine to create a <gdb.LazyString> object.
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Note: If TYPE is an array, LENGTH either must be -1 (meaning to use the
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size of the array, which may itself be unknown in which case a length of
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-1 is still used) or must be the length of the array. */
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PyObject *
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gdbpy_create_lazy_string_object (CORE_ADDR address, long length,
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const char *encoding, struct type *type)
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{
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lazy_string_object *str_obj = NULL;
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struct type *realtype;
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if (length < -1)
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{
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PyErr_SetString (PyExc_ValueError, _("Invalid length."));
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return NULL;
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}
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if (address == 0 && length != 0)
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{
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PyErr_SetString (gdbpy_gdb_memory_error,
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_("Cannot create a lazy string with address 0x0, " \
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"and a non-zero length."));
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return NULL;
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}
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if (!type)
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{
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PyErr_SetString (PyExc_RuntimeError,
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_("A lazy string's type cannot be NULL."));
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return NULL;
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}
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realtype = check_typedef (type);
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switch (realtype->code ())
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{
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case TYPE_CODE_ARRAY:
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{
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LONGEST array_length = -1;
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LONGEST low_bound, high_bound;
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if (get_array_bounds (realtype, &low_bound, &high_bound))
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array_length = high_bound - low_bound + 1;
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if (length == -1)
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length = array_length;
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else if (length != array_length)
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{
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PyErr_SetString (PyExc_ValueError, _("Invalid length."));
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return NULL;
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}
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break;
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}
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}
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str_obj = PyObject_New (lazy_string_object, &lazy_string_object_type);
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if (!str_obj)
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return NULL;
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str_obj->address = address;
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str_obj->length = length;
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if (encoding == NULL || !strcmp (encoding, ""))
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str_obj->encoding = NULL;
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else
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str_obj->encoding = xstrdup (encoding);
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str_obj->type = type_to_type_object (type);
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return (PyObject *) str_obj;
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}
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int
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gdbpy_initialize_lazy_string (void)
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{
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if (PyType_Ready (&lazy_string_object_type) < 0)
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return -1;
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Py_INCREF (&lazy_string_object_type);
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return 0;
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}
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/* Determine whether the printer object pointed to by OBJ is a
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Python lazy string. */
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int
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gdbpy_is_lazy_string (PyObject *result)
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{
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return PyObject_TypeCheck (result, &lazy_string_object_type);
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}
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/* Return the type of a character in lazy string LAZY. */
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static struct type *
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stpy_lazy_string_elt_type (lazy_string_object *lazy)
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{
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struct type *type = type_object_to_type (lazy->type);
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struct type *realtype;
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gdb_assert (type != NULL);
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realtype = check_typedef (type);
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switch (realtype->code ())
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{
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case TYPE_CODE_PTR:
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case TYPE_CODE_ARRAY:
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return TYPE_TARGET_TYPE (realtype);
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default:
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/* This is done to preserve existing behaviour. PR 20769.
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E.g., gdb.parse_and_eval("my_int_variable").lazy_string().type. */
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return realtype;
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}
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}
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/* Extract the parameters from the lazy string object STRING.
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ENCODING may be set to NULL, if no encoding is found. */
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void
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gdbpy_extract_lazy_string (PyObject *string, CORE_ADDR *addr,
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struct type **str_elt_type,
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long *length,
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gdb::unique_xmalloc_ptr<char> *encoding)
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{
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lazy_string_object *lazy;
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gdb_assert (gdbpy_is_lazy_string (string));
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lazy = (lazy_string_object *) string;
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*addr = lazy->address;
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*str_elt_type = stpy_lazy_string_elt_type (lazy);
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*length = lazy->length;
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encoding->reset (lazy->encoding ? xstrdup (lazy->encoding) : NULL);
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}
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static PyMethodDef lazy_string_object_methods[] = {
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{ "value", stpy_convert_to_value, METH_NOARGS,
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"Create a (lazy) value that contains a pointer to the string." },
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{NULL} /* Sentinel */
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};
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static gdb_PyGetSetDef lazy_string_object_getset[] = {
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{ "address", stpy_get_address, NULL, "Address of the string.", NULL },
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{ "encoding", stpy_get_encoding, NULL, "Encoding of the string.", NULL },
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{ "length", stpy_get_length, NULL, "Length of the string.", NULL },
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{ "type", stpy_get_type, NULL, "Type associated with the string.", NULL },
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{ NULL } /* Sentinel */
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};
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PyTypeObject lazy_string_object_type = {
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PyVarObject_HEAD_INIT (NULL, 0)
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"gdb.LazyString", /*tp_name*/
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sizeof (lazy_string_object), /*tp_basicsize*/
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0, /*tp_itemsize*/
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stpy_dealloc, /*tp_dealloc*/
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0, /*tp_print*/
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0, /*tp_getattr*/
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0, /*tp_setattr*/
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0, /*tp_compare*/
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0, /*tp_repr*/
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0, /*tp_as_number*/
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0, /*tp_as_sequence*/
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0, /*tp_as_mapping*/
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0, /*tp_hash */
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0, /*tp_call*/
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0, /*tp_str*/
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0, /*tp_getattro*/
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0, /*tp_setattro*/
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0, /*tp_as_buffer*/
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Py_TPFLAGS_DEFAULT, /*tp_flags*/
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"GDB lazy string object", /* tp_doc */
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0, /* tp_traverse */
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0, /* tp_clear */
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0, /* tp_richcompare */
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0, /* tp_weaklistoffset */
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0, /* tp_iter */
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0, /* tp_iternext */
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lazy_string_object_methods, /* tp_methods */
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0, /* tp_members */
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lazy_string_object_getset /* tp_getset */
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};
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