src/bindings/python/bt2/bt2/native_bt_bt2_objects.h

   1 /*
   2  * The MIT License (MIT)
   3  *
   4  * Copyright (c) 2017 Philippe Proulx <pproulx@efficios.com>
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25 #include "logging/comp-logging.h"
  26
  27
  28 /*
  29  * Useful Python objects.
  30  */
  31
  32 static PyObject *py_mod_bt2 = NULL;
  33 static PyObject *py_mod_bt2_exc_error_type = NULL;
  34 static PyObject *py_mod_bt2_exc_memory_error = NULL;
  35 static PyObject *py_mod_bt2_exc_try_again_type = NULL;
  36 static PyObject *py_mod_bt2_exc_stop_type = NULL;
  37 static PyObject *py_mod_bt2_exc_unknown_object_type = NULL;
  38
  39 static
  40 void bt_bt2_init_from_bt2(void)
  41 {
  42         /*
  43          * This is called once the bt2 package is loaded.
  44          *
  45          * Those modules and functions are needed while the package is
  46          * used. Loading them here is safe because we know the bt2
  47          * package is imported, and we know that the user cannot use the
  48          * code here without importing bt2 first.
  49          */
  50         py_mod_bt2 = PyImport_ImportModule("bt2");
  51         BT_ASSERT(py_mod_bt2);
  52         py_mod_bt2_exc_error_type =
  53                 PyObject_GetAttrString(py_mod_bt2, "_Error");
  54         BT_ASSERT(py_mod_bt2_exc_error_type);
  55         py_mod_bt2_exc_memory_error =
  56                 PyObject_GetAttrString(py_mod_bt2, "_MemoryError");
  57         BT_ASSERT(py_mod_bt2_exc_memory_error);
  58         py_mod_bt2_exc_try_again_type =
  59                 PyObject_GetAttrString(py_mod_bt2, "TryAgain");
  60         BT_ASSERT(py_mod_bt2_exc_try_again_type);
  61         py_mod_bt2_exc_stop_type =
  62                 PyObject_GetAttrString(py_mod_bt2, "Stop");
  63         BT_ASSERT(py_mod_bt2_exc_stop_type);
  64         py_mod_bt2_exc_unknown_object_type =
  65                 PyObject_GetAttrString(py_mod_bt2, "UnknownObject");
  66         BT_ASSERT(py_mod_bt2_exc_unknown_object_type);
  67 }
  68
  69 static
  70 void bt_bt2_exit_handler(void)
  71 {
  72         /*
  73          * This is an exit handler (set by the bt2 package).
  74          *
  75          * We only give back the references that we took in
  76          * bt_bt2_init_from_bt2() here. The global variables continue
  77          * to exist for the code of this file, but they are now borrowed
  78          * references. If this code is executed, it means that somehow
  79          * the modules are still loaded, so it should be safe to use
  80          * them even without a strong reference.
  81          *
  82          * We cannot do this in the library's destructor because it
  83          * gets executed once Python is already finalized.
  84          */
  85         Py_XDECREF(py_mod_bt2);
  86         Py_XDECREF(py_mod_bt2_exc_error_type);
  87         Py_XDECREF(py_mod_bt2_exc_try_again_type);
  88         Py_XDECREF(py_mod_bt2_exc_stop_type);
  89         Py_XDECREF(py_mod_bt2_exc_unknown_object_type);
  90 }