py-evtregistry.c revision 1.7 
1/* Python interface to inferior thread event registries.
2
3   Copyright (C) 2009-2017 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 "command.h"
22#include "py-events.h"
23#include "py-ref.h"
24
25events_object gdb_py_events;
26
27extern PyTypeObject eventregistry_object_type
28    CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("eventregistry_object");
29
30/* Implementation of EventRegistry.connect () -> NULL.
31   Add FUNCTION to the list of listeners.  */
32
33static PyObject *
34evregpy_connect (PyObject *self, PyObject *function)
35{
36  PyObject *func;
37  PyObject *callback_list = (((eventregistry_object *) self)->callbacks);
38
39  if (!PyArg_ParseTuple (function, "O", &func))
40    return NULL;
41
42  if (!PyCallable_Check (func))
43    {
44      PyErr_SetString (PyExc_RuntimeError, "Function is not callable");
45      return NULL;
46    }
47
48  if (PyList_Append (callback_list, func) < 0)
49    return NULL;
50
51  Py_RETURN_NONE;
52}
53
54/* Implementation of EventRegistry.disconnect () -> NULL.
55   Remove FUNCTION from the list of listeners.  */
56
57static PyObject *
58evregpy_disconnect (PyObject *self, PyObject *function)
59{
60  PyObject *func;
61  int index;
62  PyObject *callback_list = (((eventregistry_object *) self)->callbacks);
63
64  if (!PyArg_ParseTuple (function, "O", &func))
65    return NULL;
66
67  index = PySequence_Index (callback_list, func);
68  if (index < 0)
69    Py_RETURN_NONE;
70
71  if (PySequence_DelItem (callback_list, index) < 0)
72    return NULL;
73
74  Py_RETURN_NONE;
75}
76
77/* Create a new event registry.  This function uses PyObject_New
78   and therefore returns a new reference that callers must handle.  */
79
80eventregistry_object *
81create_eventregistry_object (void)
82{
83  gdbpy_ref<eventregistry_object>
84    eventregistry_obj (PyObject_New (eventregistry_object,
85				     &eventregistry_object_type));
86
87  if (eventregistry_obj == NULL)
88    return NULL;
89
90  eventregistry_obj->callbacks = PyList_New (0);
91  if (!eventregistry_obj->callbacks)
92    return NULL;
93
94  return eventregistry_obj.release ();
95}
96
97static void
98evregpy_dealloc (PyObject *self)
99{
100  Py_XDECREF (((eventregistry_object *) self)->callbacks);
101  Py_TYPE (self)->tp_free (self);
102}
103
104/* Initialize the Python event registry code.  */
105
106int
107gdbpy_initialize_eventregistry (void)
108{
109  if (PyType_Ready (&eventregistry_object_type) < 0)
110    return -1;
111
112  return gdb_pymodule_addobject (gdb_module, "EventRegistry",
113				 (PyObject *) &eventregistry_object_type);
114}
115
116/* Retern the number of listeners currently connected to this
117   registry.  */
118
119int
120evregpy_no_listeners_p (eventregistry_object *registry)
121{
122  return PyList_Size (registry->callbacks) == 0;
123}
124
125static PyMethodDef eventregistry_object_methods[] =
126{
127  { "connect", evregpy_connect, METH_VARARGS, "Add function" },
128  { "disconnect", evregpy_disconnect, METH_VARARGS, "Remove function" },
129  { NULL } /* Sentinel.  */
130};
131
132PyTypeObject eventregistry_object_type =
133{
134  PyVarObject_HEAD_INIT (NULL, 0)
135  "gdb.EventRegistry",                        /* tp_name */
136  sizeof (eventregistry_object),              /* tp_basicsize */
137  0,                                          /* tp_itemsize */
138  evregpy_dealloc,                            /* tp_dealloc */
139  0,                                          /* tp_print */
140  0,                                          /* tp_getattr */
141  0,                                          /* tp_setattr */
142  0,                                          /* tp_compare */
143  0,                                          /* tp_repr */
144  0,                                          /* tp_as_number */
145  0,                                          /* tp_as_sequence */
146  0,                                          /* tp_as_mapping */
147  0,                                          /* tp_hash  */
148  0,                                          /* tp_call */
149  0,                                          /* tp_str */
150  0,                                          /* tp_getattro */
151  0,                                          /* tp_setattro */
152  0,                                          /* tp_as_buffer */
153  Py_TPFLAGS_DEFAULT,                         /* tp_flags */
154  "GDB event registry object",                /* tp_doc */
155  0,                                          /* tp_traverse */
156  0,                                          /* tp_clear */
157  0,                                          /* tp_richcompare */
158  0,                                          /* tp_weaklistoffset */
159  0,                                          /* tp_iter */
160  0,                                          /* tp_iternext */
161  eventregistry_object_methods,               /* tp_methods */
162  0,                                          /* tp_members */
163  0,                                          /* tp_getset */
164  0,                                          /* tp_base */
165  0,                                          /* tp_dict */
166  0,                                          /* tp_descr_get */
167  0,                                          /* tp_descr_set */
168  0,                                          /* tp_dictoffset */
169  0,                                          /* tp_init */
170  0                                           /* tp_alloc */
171};
172