xref: /netbsd-src/external/gpl3/gdb.old/dist/gdb/python/py-varobj.c (revision 8b657b0747480f8989760d71343d6dd33f8d4cf9)
1 /* Copyright (C) 2013-2023 Free Software Foundation, Inc.
2 
3    This program is free software; you can redistribute it and/or modify
4    it under the terms of the GNU General Public License as published by
5    the Free Software Foundation; either version 3 of the License, or
6    (at your option) any later version.
7 
8    This program is distributed in the hope that it will be useful,
9    but WITHOUT ANY WARRANTY; without even the implied warranty of
10    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11    GNU General Public License for more details.
12 
13    You should have received a copy of the GNU General Public License
14    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
15 
16 #include "defs.h"
17 #include "python-internal.h"
18 #include "varobj.h"
19 #include "varobj-iter.h"
20 #include "valprint.h"
21 
22 /* A dynamic varobj iterator "class" for python pretty-printed
23    varobjs.  This inherits struct varobj_iter.  */
24 
25 struct py_varobj_iter : public varobj_iter
26 {
27   py_varobj_iter (struct varobj *var, gdbpy_ref<> &&pyiter,
28 		  const value_print_options *opts);
29   ~py_varobj_iter () override;
30 
31   std::unique_ptr<varobj_item> next () override;
32 
33 private:
34 
35   /* The varobj this iterator is listing children for.  */
36   struct varobj *m_var;
37 
38   /* The next raw index we will try to check is available.  If it is
39      equal to number_of_children, then we've already iterated the
40      whole set.  */
41   int m_next_raw_index = 0;
42 
43   /* The python iterator returned by the printer's 'children' method,
44      or NULL if not available.  */
45   PyObject *m_iter;
46 
47   /* The print options to use.  */
48   value_print_options m_opts;
49 };
50 
51 /* Implementation of the 'dtor' method of pretty-printed varobj
52    iterators.  */
53 
54 py_varobj_iter::~py_varobj_iter ()
55 {
56   gdbpy_enter_varobj enter_py (m_var);
57   Py_XDECREF (m_iter);
58 }
59 
60 /* Implementation of the 'next' method of pretty-printed varobj
61    iterators.  */
62 
63 std::unique_ptr<varobj_item>
64 py_varobj_iter::next ()
65 {
66   PyObject *py_v;
67   varobj_item *vitem;
68   const char *name = NULL;
69 
70   if (!gdb_python_initialized)
71     return NULL;
72 
73   gdbpy_enter_varobj enter_py (m_var);
74 
75   scoped_restore set_options = make_scoped_restore (&gdbpy_current_print_options,
76 						    &m_opts);
77 
78   gdbpy_ref<> item (PyIter_Next (m_iter));
79 
80   if (item == NULL)
81     {
82       /* Normal end of iteration.  */
83       if (!PyErr_Occurred ())
84 	return NULL;
85 
86       /* If we got a memory error, just use the text as the item.  */
87       if (PyErr_ExceptionMatches (gdbpy_gdb_memory_error))
88 	{
89 	  gdbpy_err_fetch fetched_error;
90 	  gdb::unique_xmalloc_ptr<char> value_str = fetched_error.to_string ();
91 	  if (value_str == NULL)
92 	    {
93 	      gdbpy_print_stack ();
94 	      return NULL;
95 	    }
96 
97 	  std::string name_str = string_printf ("<error at %d>",
98 						m_next_raw_index++);
99 	  item.reset (Py_BuildValue ("(ss)", name_str.c_str (),
100 				     value_str.get ()));
101 	  if (item == NULL)
102 	    {
103 	      gdbpy_print_stack ();
104 	      return NULL;
105 	    }
106 	}
107       else
108 	{
109 	  /* Any other kind of error.  */
110 	  gdbpy_print_stack ();
111 	  return NULL;
112 	}
113     }
114 
115   if (!PyArg_ParseTuple (item.get (), "sO", &name, &py_v))
116     {
117       gdbpy_print_stack ();
118       error (_("Invalid item from the child list"));
119     }
120 
121   vitem = new varobj_item ();
122   vitem->value = release_value (convert_value_from_python (py_v));
123   if (vitem->value == NULL)
124     gdbpy_print_stack ();
125   vitem->name = name;
126 
127   m_next_raw_index++;
128   return std::unique_ptr<varobj_item> (vitem);
129 }
130 
131 /* Constructor of pretty-printed varobj iterators.  VAR is the varobj
132    whose children the iterator will be iterating over.  PYITER is the
133    python iterator actually responsible for the iteration.  */
134 
135 py_varobj_iter::py_varobj_iter (struct varobj *var, gdbpy_ref<> &&pyiter,
136 				const value_print_options *opts)
137   : m_var (var),
138     m_iter (pyiter.release ()),
139     m_opts (*opts)
140 {
141 }
142 
143 /* Return a new pretty-printed varobj iterator suitable to iterate
144    over VAR's children.  */
145 
146 std::unique_ptr<varobj_iter>
147 py_varobj_get_iterator (struct varobj *var, PyObject *printer,
148 			const value_print_options *opts)
149 {
150   gdbpy_enter_varobj enter_py (var);
151 
152   if (!PyObject_HasAttr (printer, gdbpy_children_cst))
153     return NULL;
154 
155   scoped_restore set_options = make_scoped_restore (&gdbpy_current_print_options,
156 						    opts);
157 
158   gdbpy_ref<> children (PyObject_CallMethodObjArgs (printer, gdbpy_children_cst,
159 						    NULL));
160   if (children == NULL)
161     {
162       gdbpy_print_stack ();
163       error (_("Null value returned for children"));
164     }
165 
166   gdbpy_ref<> iter (PyObject_GetIter (children.get ()));
167   if (iter == NULL)
168     {
169       gdbpy_print_stack ();
170       error (_("Could not get children iterator"));
171     }
172 
173   return std::unique_ptr<varobj_iter> (new py_varobj_iter (var,
174 							   std::move (iter),
175 							   opts));
176 }
177