1 /* Python interface to inferior thread event registries.
2 
3    Copyright (C) 2009-2012 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 
24 events_object gdb_py_events;
25 
26 static PyTypeObject eventregistry_object_type;
27 
28 /* Implementation of EventRegistry.connect () -> NULL.
29    Add FUNCTION to the list of listeners.  */
30 
31 static PyObject *
32 evregpy_connect (PyObject *self, PyObject *function)
33 {
34   PyObject *func;
35   PyObject *callback_list = (((eventregistry_object *) self)->callbacks);
36 
37   if (!PyArg_ParseTuple (function, "O", &func))
38     return NULL;
39 
40   if (!PyCallable_Check (func))
41     {
42       PyErr_SetString (PyExc_RuntimeError, "Function is not callable");
43       return NULL;
44     }
45 
46   if (PyList_Append (callback_list, func) < 0)
47     return NULL;
48 
49   Py_RETURN_NONE;
50 }
51 
52 /* Implementation of EventRegistry.disconnect () -> NULL.
53    Remove FUNCTION from the list of listeners.  */
54 
55 static PyObject *
56 evregpy_disconnect (PyObject *self, PyObject *function)
57 {
58   PyObject *func;
59   int index;
60   PyObject *callback_list = (((eventregistry_object *) self)->callbacks);
61 
62   if (!PyArg_ParseTuple (function, "O", &func))
63     return NULL;
64 
65   index = PySequence_Index (callback_list, func);
66   if (index < 0)
67     Py_RETURN_NONE;
68 
69   if (PySequence_DelItem (callback_list, index) < 0)
70     return NULL;
71 
72   Py_RETURN_NONE;
73 }
74 
75 /* Create a new event registry.  This function uses PyObject_New
76    and therefore returns a new reference that callers must handle.  */
77 
78 eventregistry_object *
79 create_eventregistry_object (void)
80 {
81   eventregistry_object *eventregistry_obj;
82 
83   eventregistry_obj = PyObject_New (eventregistry_object,
84                                     &eventregistry_object_type);
85 
86   if (!eventregistry_obj)
87     return NULL;
88 
89   eventregistry_obj->callbacks = PyList_New (0);
90   if (!eventregistry_obj->callbacks)
91     return NULL;
92 
93   return eventregistry_obj;
94 }
95 
96 static void
97 evregpy_dealloc (PyObject *self)
98 {
99   Py_XDECREF (((eventregistry_object *) self)->callbacks);
100   self->ob_type->tp_free (self);
101 }
102 
103 /* Initialize the Python event registry code.  */
104 
105 void
106 gdbpy_initialize_eventregistry (void)
107 {
108   if (PyType_Ready (&eventregistry_object_type) < 0)
109     return;
110 
111   Py_INCREF (&eventregistry_object_type);
112   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 
119 int
120 evregpy_no_listeners_p (eventregistry_object *registry)
121 {
122   return PyList_Size (registry->callbacks) == 0;
123 }
124 
125 static 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 
132 static PyTypeObject eventregistry_object_type =
133 {
134   PyObject_HEAD_INIT (NULL)
135   0,                                          /* ob_size */
136   "gdb.EventRegistry",                        /* tp_name */
137   sizeof (eventregistry_object),              /* tp_basicsize */
138   0,                                          /* tp_itemsize */
139   evregpy_dealloc,                            /* tp_dealloc */
140   0,                                          /* tp_print */
141   0,                                          /* tp_getattr */
142   0,                                          /* tp_setattr */
143   0,                                          /* tp_compare */
144   0,                                          /* tp_repr */
145   0,                                          /* tp_as_number */
146   0,                                          /* tp_as_sequence */
147   0,                                          /* tp_as_mapping */
148   0,                                          /* tp_hash  */
149   0,                                          /* tp_call */
150   0,                                          /* tp_str */
151   0,                                          /* tp_getattro */
152   0,                                          /* tp_setattro */
153   0,                                          /* tp_as_buffer */
154   Py_TPFLAGS_DEFAULT,                         /* tp_flags */
155   "GDB event registry object",                /* tp_doc */
156   0,                                          /* tp_traverse */
157   0,                                          /* tp_clear */
158   0,                                          /* tp_richcompare */
159   0,                                          /* tp_weaklistoffset */
160   0,                                          /* tp_iter */
161   0,                                          /* tp_iternext */
162   eventregistry_object_methods,               /* tp_methods */
163   0,                                          /* tp_members */
164   0,                                          /* tp_getset */
165   0,                                          /* tp_base */
166   0,                                          /* tp_dict */
167   0,                                          /* tp_descr_get */
168   0,                                          /* tp_descr_set */
169   0,                                          /* tp_dictoffset */
170   0,                                          /* tp_init */
171   0                                           /* tp_alloc */
172 };
173