ceph/src/boost/libs/python/src/object/life_support.cpp

   1 // Copyright David Abrahams 2002.
   2 // Distributed under the Boost Software License, Version 1.0. (See
   3 // accompanying file LICENSE_1_0.txt or copy at
   4 // http://www.boost.org/LICENSE_1_0.txt)
   5 #include <boost/python/object/life_support.hpp>
   6 #include <boost/python/detail/none.hpp>
   7 #include <boost/python/refcount.hpp>
   8
   9 namespace boost { namespace python { namespace objects {
  10
  11 struct life_support
  12 {
  13     PyObject_HEAD
  14     PyObject* patient;
  15 };
  16
  17 extern "C"
  18 {
  19     static void
  20     life_support_dealloc(PyObject* self)
  21     {
  22         Py_XDECREF(((life_support*)self)->patient);
  23         self->ob_type->tp_free(self);
  24     }
  25
  26     static PyObject *
  27     life_support_call(PyObject *self, PyObject *arg, PyObject * /*kw*/)
  28     {
  29         // Let the patient die now
  30         Py_XDECREF(((life_support*)self)->patient);
  31         ((life_support*)self)->patient = 0;
  32         // Let the weak reference die. This probably kills us.
  33         Py_XDECREF(PyTuple_GET_ITEM(arg, 0));
  34         return ::boost::python::detail::none();
  35     }
  36 }
  37
  38 PyTypeObject life_support_type = {
  39     PyVarObject_HEAD_INIT(NULL, 0)//(&PyType_Type)
  40     const_cast<char*>("Boost.Python.life_support"),
  41     sizeof(life_support),
  42     0,
  43     life_support_dealloc,               /* tp_dealloc */
  44     0,                                  /* tp_print */
  45     0,                                  /* tp_getattr */
  46     0,                                  /* tp_setattr */
  47     0,                                  /* tp_compare */
  48     0, //(reprfunc)func_repr,                   /* tp_repr */
  49     0,                                  /* tp_as_number */
  50     0,                                  /* tp_as_sequence */
  51     0,                                  /* tp_as_mapping */
  52     0,                                  /* tp_hash */
  53     life_support_call,                  /* tp_call */
  54     0,                                  /* tp_str */
  55     0, // PyObject_GenericGetAttr,            /* tp_getattro */
  56     0, // PyObject_GenericSetAttr,            /* tp_setattro */
  57     0,                                  /* tp_as_buffer */
  58     Py_TPFLAGS_DEFAULT /* | Py_TPFLAGS_HAVE_GC */,/* tp_flags */
  59     0,                                  /* tp_doc */
  60     0, // (traverseproc)func_traverse,          /* tp_traverse */
  61     0,                                  /* tp_clear */
  62     0,                                  /* tp_richcompare */
  63     0, //offsetof(PyLife_SupportObject, func_weakreflist), /* tp_weaklistoffset */
  64     0,                                  /* tp_iter */
  65     0,                                  /* tp_iternext */
  66     0,                                  /* tp_methods */
  67     0, // func_memberlist,                      /* tp_members */
  68     0, //func_getsetlist,                       /* tp_getset */
  69     0,                                  /* tp_base */
  70     0,                                  /* tp_dict */
  71     0,                                  /* tp_descr_get */
  72     0,                                  /* tp_descr_set */
  73     0, //offsetof(PyLife_SupportObject, func_dict),      /* tp_dictoffset */
  74     0,                                      /* tp_init */
  75     0,                                      /* tp_alloc */
  76     0,                                      /* tp_new */
  77     0,                                      /* tp_free */
  78     0,                                      /* tp_is_gc */
  79     0,                                      /* tp_bases */
  80     0,                                      /* tp_mro */
  81     0,                                      /* tp_cache */
  82     0,                                      /* tp_subclasses */
  83     0,                                      /* tp_weaklist */
  84 #if PYTHON_API_VERSION >= 1012
  85     0                                       /* tp_del */
  86 #endif
  87 };
  88
  89 PyObject* make_nurse_and_patient(PyObject* nurse, PyObject* patient)
  90 {
  91     if (nurse == Py_None || nurse == patient)
  92         return nurse;
  93
  94     if (Py_TYPE(&life_support_type) == 0)
  95     {
  96         Py_TYPE(&life_support_type) = &PyType_Type;
  97         PyType_Ready(&life_support_type);
  98     }
  99
 100     life_support* system = PyObject_New(life_support, &life_support_type);
 101     if (!system)
 102         return 0;
 103
 104     system->patient = 0;
 105
 106     // We're going to leak this reference, but don't worry; the
 107     // life_support system decrements it when the nurse dies.
 108     PyObject* weakref = PyWeakref_NewRef(nurse, (PyObject*)system);
 109
 110     // weakref has either taken ownership, or we have to release it
 111     // anyway
 112     Py_DECREF(system);
 113     if (!weakref)
 114         return 0;
 115
 116     system->patient = patient;
 117     Py_XINCREF(patient); // hang on to the patient until death
 118     return weakref;
 119 }
 120
 121 }}} // namespace boost::python::objects