Panda3D
pythonCallbackObject.cxx
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1 /**
2  * PANDA 3D SOFTWARE
3  * Copyright (c) Carnegie Mellon University. All rights reserved.
4  *
5  * All use of this software is subject to the terms of the revised BSD
6  * license. You should have received a copy of this license along
7  * with this source code in a file named "LICENSE."
8  *
9  * @file pythonCallbackObject.cxx
10  * @author drose
11  * @date 2009-03-13
12  */
13 
14 #include "pythonCallbackObject.h"
15 
16 #ifdef HAVE_PYTHON
17 
18 #include "py_panda.h"
19 #include "pythonThread.h"
20 #include "callbackData.h"
21 #include "config_putil.h"
22 
23 TypeHandle PythonCallbackObject::_type_handle;
24 
25 Configure(config_pythonCallbackObject);
26 ConfigureFn(config_pythonCallbackObject) {
27  PythonCallbackObject::init_type();
28 }
29 
30 #ifndef CPPPARSER
31 extern struct Dtool_PyTypedObject Dtool_TypedObject;
32 #endif
33 
34 /**
35  *
36  */
37 PythonCallbackObject::
38 PythonCallbackObject(PyObject *function) {
39  _function = Py_None;
40  Py_INCREF(_function);
41 
42  set_function(function);
43 
44 #if !defined(SIMPLE_THREADS) && defined(WITH_THREAD)
45  // Ensure that the Python threading system is initialized and ready to go.
46 
47 #if PY_VERSION_HEX >= 0x03020000
48  Py_Initialize();
49 #endif
50 
51 #if PY_VERSION_HEX < 0x03090000
52  // PyEval_InitThreads is now a deprecated no-op in Python 3.9+
53  PyEval_InitThreads();
54 #endif // PY_VERSION_HEX
55 #endif // WITH_THREAD
56 }
57 
58 /**
59  *
60  */
61 PythonCallbackObject::
62 ~PythonCallbackObject() {
63  Py_DECREF(_function);
64 }
65 
66 /**
67  * Replaces the function that is called for the callback. runs. The
68  * parameter should be a Python callable object.
69  */
70 void PythonCallbackObject::
71 set_function(PyObject *function) {
72  Py_DECREF(_function);
73  _function = function;
74  Py_INCREF(_function);
75  if (_function != Py_None && !PyCallable_Check(_function)) {
76  nassert_raise("Invalid function passed to PythonCallbackObject");
77  }
78 }
79 
80 /**
81  * Returns the function that is called for the callback.
82  */
83 PyObject *PythonCallbackObject::
84 get_function() {
85  Py_INCREF(_function);
86  return _function;
87 }
88 
89 /**
90  * This method called when the callback is triggered; it *replaces* the
91  * original function. To continue performing the original function, you must
92  * call cbdata->upcall() during the callback.
93  */
94 void PythonCallbackObject::
95 do_callback(CallbackData *cbdata) {
96 #if defined(HAVE_THREADS) && !defined(SIMPLE_THREADS)
97  // Use PyGILState to protect this asynchronous call.
98  PyGILState_STATE gstate;
99  gstate = PyGILState_Ensure();
100 #endif
101 
102  do_python_callback(cbdata);
103 
104 #if defined(HAVE_THREADS) && !defined(SIMPLE_THREADS)
105  PyGILState_Release(gstate);
106 #endif
107 }
108 
109 /**
110  * The Python calls that implement do_callback(). This function is separate
111  * so we can acquire the Python interpretor lock while it runs.
112  */
113 void PythonCallbackObject::
114 do_python_callback(CallbackData *cbdata) {
115  nassertv(cbdata != nullptr);
116 
117  // Wrap the cbdata up in a Python object, then put it in a tuple, for the
118  // argument list.
119  PyObject *pycbdata =
120  DTool_CreatePyInstanceTyped(cbdata, Dtool_TypedObject,
121  false, false, cbdata->get_type_index());
122  PyObject *args = Py_BuildValue("(O)", pycbdata);
123  Py_DECREF(pycbdata);
124 
125  PyObject *result = PythonThread::call_python_func(_function, args);
126  Py_DECREF(args);
127 
128  if (result == nullptr) {
129  if (PyErr_Occurred() != PyExc_SystemExit) {
130  util_cat.error()
131  << "Exception occurred in " << *this << "\n";
132  }
133  } else {
134  Py_DECREF(result);
135  }
136 }
137 
138 #endif // HAVE_PYTHON
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.
This is a generic data block that is passed along to a CallbackObject when a callback is made.
Definition: callbackData.h:29
TypeHandle is the identifier used to differentiate C++ class types.
Definition: typeHandle.h:81
int get_type_index() const
Returns the internal index number associated with this object's TypeHandle, a unique number for each ...
Definition: typedObject.I:20
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.