gdb/python/py-evtregistry.c

   1 /* Python interface to inferior thread event registries.
   2
   3    Copyright (C) 2009-2020 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 extern PyTypeObject eventregistry_object_type
  27     CPYCHECKER_TYPE_OBJECT_FOR_TYPEDEF ("eventregistry_object");
  28
  29 /* Implementation of EventRegistry.connect () -> NULL.
  30    Add FUNCTION to the list of listeners.  */
  31
  32 static PyObject *
  33 evregpy_connect (PyObject *self, PyObject *function)
  34 {
  35   PyObject *func;
  36   PyObject *callback_list = (((eventregistry_object *) self)->callbacks);
  37
  38   if (!PyArg_ParseTuple (function, "O", &func))
  39     return NULL;
  40
  41   if (!PyCallable_Check (func))
  42     {
  43       PyErr_SetString (PyExc_RuntimeError, "Function is not callable");
  44       return NULL;
  45     }
  46
  47   if (PyList_Append (callback_list, func) < 0)
  48     return NULL;
  49
  50   Py_RETURN_NONE;
  51 }
  52
  53 /* Implementation of EventRegistry.disconnect () -> NULL.
  54    Remove FUNCTION from the list of listeners.  */
  55
  56 static PyObject *
  57 evregpy_disconnect (PyObject *self, PyObject *function)
  58 {
  59   PyObject *func;
  60   int index;
  61   PyObject *callback_list = (((eventregistry_object *) self)->callbacks);
  62
  63   if (!PyArg_ParseTuple (function, "O", &func))
  64     return NULL;
  65
  66   index = PySequence_Index (callback_list, func);
  67   if (index < 0)
  68     Py_RETURN_NONE;
  69
  70   if (PySequence_DelItem (callback_list, index) < 0)
  71     return NULL;
  72
  73   Py_RETURN_NONE;
  74 }
  75
  76 /* Create a new event registry.  This function uses PyObject_New
  77    and therefore returns a new reference that callers must handle.  */
  78
  79 eventregistry_object *
  80 create_eventregistry_object (void)
  81 {
  82   gdbpy_ref<eventregistry_object>
  83     eventregistry_obj (PyObject_New (eventregistry_object,
  84                                      &eventregistry_object_type));
  85
  86   if (eventregistry_obj == NULL)
  87     return NULL;
  88
  89   eventregistry_obj->callbacks = PyList_New (0);
  90   if (!eventregistry_obj->callbacks)
  91     return NULL;
  92
  93   return eventregistry_obj.release ();
  94 }
  95
  96 static void
  97 evregpy_dealloc (PyObject *self)
  98 {
  99   Py_XDECREF (((eventregistry_object *) self)->callbacks);
 100   Py_TYPE (self)->tp_free (self);
 101 }
 102
 103 /* Initialize the Python event registry code.  */
 104
 105 int
 106 gdbpy_initialize_eventregistry (void)
 107 {
 108   if (PyType_Ready (&eventregistry_object_type) < 0)
 109     return -1;
 110
 111   return gdb_pymodule_addobject (gdb_module, "EventRegistry",
 112                                  (PyObject *) &eventregistry_object_type);
 113 }
 114
 115 /* Return the number of listeners currently connected to this
 116    registry.  */
 117
 118 int
 119 evregpy_no_listeners_p (eventregistry_object *registry)
 120 {
 121   return PyList_Size (registry->callbacks) == 0;
 122 }
 123
 124 static PyMethodDef eventregistry_object_methods[] =
 125 {
 126   { "connect", evregpy_connect, METH_VARARGS, "Add function" },
 127   { "disconnect", evregpy_disconnect, METH_VARARGS, "Remove function" },
 128   { NULL } /* Sentinel.  */
 129 };
 130
 131 PyTypeObject eventregistry_object_type =
 132 {
 133   PyVarObject_HEAD_INIT (NULL, 0)
 134   "gdb.EventRegistry",                        /* tp_name */
 135   sizeof (eventregistry_object),              /* tp_basicsize */
 136   0,                                          /* tp_itemsize */
 137   evregpy_dealloc,                            /* tp_dealloc */
 138   0,                                          /* tp_print */
 139   0,                                          /* tp_getattr */
 140   0,                                          /* tp_setattr */
 141   0,                                          /* tp_compare */
 142   0,                                          /* tp_repr */
 143   0,                                          /* tp_as_number */
 144   0,                                          /* tp_as_sequence */
 145   0,                                          /* tp_as_mapping */
 146   0,                                          /* tp_hash  */
 147   0,                                          /* tp_call */
 148   0,                                          /* tp_str */
 149   0,                                          /* tp_getattro */
 150   0,                                          /* tp_setattro */
 151   0,                                          /* tp_as_buffer */
 152   Py_TPFLAGS_DEFAULT,                         /* tp_flags */
 153   "GDB event registry object",                /* tp_doc */
 154   0,                                          /* tp_traverse */
 155   0,                                          /* tp_clear */
 156   0,                                          /* tp_richcompare */
 157   0,                                          /* tp_weaklistoffset */
 158   0,                                          /* tp_iter */
 159   0,                                          /* tp_iternext */
 160   eventregistry_object_methods,               /* tp_methods */
 161   0,                                          /* tp_members */
 162   0,                                          /* tp_getset */
 163   0,                                          /* tp_base */
 164   0,                                          /* tp_dict */
 165   0,                                          /* tp_descr_get */
 166   0,                                          /* tp_descr_set */
 167   0,                                          /* tp_dictoffset */
 168   0,                                          /* tp_init */
 169   0                                           /* tp_alloc */
 170 };