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

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright (c) 2017 Philippe Proulx <pproulx@efficios.com>
   5  */
   6
   7 #ifndef BABELTRACE_BINDINGS_PYTHON_BT2_BT2_NATIVE_BT_BT2_OBJECTS_H
   8 #define BABELTRACE_BINDINGS_PYTHON_BT2_BT2_NATIVE_BT_BT2_OBJECTS_H
   9
  10 #include "logging/comp-logging.h"
  11
  12 /*
  13  * Useful Python objects.
  14  */
  15
  16 static PyObject *py_mod_bt2 = NULL;
  17 static PyObject *py_mod_bt2_exc_error_type = NULL;
  18 static PyObject *py_mod_bt2_exc_memory_error = NULL;
  19 static PyObject *py_mod_bt2_exc_try_again_type = NULL;
  20 static PyObject *py_mod_bt2_exc_stop_type = NULL;
  21 static PyObject *py_mod_bt2_exc_unknown_object_type = NULL;
  22
  23 static
  24 void bt_bt2_init_from_bt2(void)
  25 {
  26         /*
  27          * This is called once the bt2 package is loaded.
  28          *
  29          * Those modules and functions are needed while the package is
  30          * used. Loading them here is safe because we know the bt2
  31          * package is imported, and we know that the user cannot use the
  32          * code here without importing bt2 first.
  33          */
  34         py_mod_bt2 = PyImport_ImportModule("bt2");
  35         BT_ASSERT(py_mod_bt2);
  36         py_mod_bt2_exc_error_type =
  37                 PyObject_GetAttrString(py_mod_bt2, "_Error");
  38         BT_ASSERT(py_mod_bt2_exc_error_type);
  39         py_mod_bt2_exc_memory_error =
  40                 PyObject_GetAttrString(py_mod_bt2, "_MemoryError");
  41         BT_ASSERT(py_mod_bt2_exc_memory_error);
  42         py_mod_bt2_exc_try_again_type =
  43                 PyObject_GetAttrString(py_mod_bt2, "TryAgain");
  44         BT_ASSERT(py_mod_bt2_exc_try_again_type);
  45         py_mod_bt2_exc_stop_type =
  46                 PyObject_GetAttrString(py_mod_bt2, "Stop");
  47         BT_ASSERT(py_mod_bt2_exc_stop_type);
  48         py_mod_bt2_exc_unknown_object_type =
  49                 PyObject_GetAttrString(py_mod_bt2, "UnknownObject");
  50         BT_ASSERT(py_mod_bt2_exc_unknown_object_type);
  51 }
  52
  53 static
  54 void bt_bt2_exit_handler(void)
  55 {
  56         /*
  57          * This is an exit handler (set by the bt2 package).
  58          *
  59          * We only give back the references that we took in
  60          * bt_bt2_init_from_bt2() here. The global variables continue
  61          * to exist for the code of this file, but they are now borrowed
  62          * references. If this code is executed, it means that somehow
  63          * the modules are still loaded, so it should be safe to use
  64          * them even without a strong reference.
  65          *
  66          * We cannot do this in the library's destructor because it
  67          * gets executed once Python is already finalized.
  68          */
  69         Py_XDECREF(py_mod_bt2);
  70         Py_XDECREF(py_mod_bt2_exc_error_type);
  71         Py_XDECREF(py_mod_bt2_exc_try_again_type);
  72         Py_XDECREF(py_mod_bt2_exc_stop_type);
  73         Py_XDECREF(py_mod_bt2_exc_unknown_object_type);
  74 }
  75
  76 #endif /* BABELTRACE_BINDINGS_PYTHON_BT2_BT2_NATIVE_BT_BT2_OBJECTS_H */