Merge commit '4ebe6417a5fce5f0994fc0c31bebf732be96a07c' as 'boost'

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

@@ -0,0 +1,121 @@
+// Copyright David Abrahams 2002.
+// Distributed under the Boost Software License, Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+#include <boost/python/object/life_support.hpp>
+#include <boost/python/detail/none.hpp>
+#include <boost/python/refcount.hpp>
+
+namespace boost { namespace python { namespace objects { 
+
+struct life_support
+{
+    PyObject_HEAD
+    PyObject* patient;
+};
+
+extern "C"
+{
+    static void
+    life_support_dealloc(PyObject* self)
+    {
+        Py_XDECREF(((life_support*)self)->patient);
+        self->ob_type->tp_free(self);
+    }
+
+    static PyObject *
+    life_support_call(PyObject *self, PyObject *arg, PyObject * /*kw*/)
+    {
+        // Let the patient die now
+        Py_XDECREF(((life_support*)self)->patient);
+        ((life_support*)self)->patient = 0;
+        // Let the weak reference die. This probably kills us.
+        Py_XDECREF(PyTuple_GET_ITEM(arg, 0));
+        return ::boost::python::detail::none();
+    }
+}
+
+PyTypeObject life_support_type = {
+    PyVarObject_HEAD_INIT(NULL, 0)//(&PyType_Type)
+    const_cast<char*>("Boost.Python.life_support"),
+    sizeof(life_support),
+    0,
+    life_support_dealloc,               /* tp_dealloc */
+    0,                                  /* tp_print */
+    0,                                  /* tp_getattr */
+    0,                                  /* tp_setattr */
+    0,                                  /* tp_compare */
+    0, //(reprfunc)func_repr,                   /* tp_repr */
+    0,                                  /* tp_as_number */
+    0,                                  /* tp_as_sequence */
+    0,                                  /* tp_as_mapping */
+    0,                                  /* tp_hash */
+    life_support_call,                  /* tp_call */
+    0,                                  /* tp_str */
+    0, // PyObject_GenericGetAttr,            /* tp_getattro */
+    0, // PyObject_GenericSetAttr,            /* tp_setattro */
+    0,                                  /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT /* | Py_TPFLAGS_HAVE_GC */,/* tp_flags */
+    0,                                  /* tp_doc */
+    0, // (traverseproc)func_traverse,          /* tp_traverse */
+    0,                                  /* tp_clear */
+    0,                                  /* tp_richcompare */
+    0, //offsetof(PyLife_SupportObject, func_weakreflist), /* tp_weaklistoffset */
+    0,                                  /* tp_iter */
+    0,                                  /* tp_iternext */
+    0,                                  /* tp_methods */
+    0, // func_memberlist,                      /* tp_members */
+    0, //func_getsetlist,                       /* tp_getset */
+    0,                                  /* tp_base */
+    0,                                  /* tp_dict */
+    0,                                  /* tp_descr_get */
+    0,                                  /* tp_descr_set */
+    0, //offsetof(PyLife_SupportObject, func_dict),      /* tp_dictoffset */
+    0,                                      /* tp_init */
+    0,                                      /* tp_alloc */
+    0,                                      /* tp_new */
+    0,                                      /* tp_free */
+    0,                                      /* tp_is_gc */
+    0,                                      /* tp_bases */
+    0,                                      /* tp_mro */
+    0,                                      /* tp_cache */
+    0,                                      /* tp_subclasses */
+    0,                                      /* tp_weaklist */
+#if PYTHON_API_VERSION >= 1012
+    0                                       /* tp_del */
+#endif
+};
+
+PyObject* make_nurse_and_patient(PyObject* nurse, PyObject* patient)
+{
+    if (nurse == Py_None || nurse == patient)
+        return nurse;
+    
+    if (Py_TYPE(&life_support_type) == 0)
+    {
+        Py_TYPE(&life_support_type) = &PyType_Type;
+        PyType_Ready(&life_support_type);
+    }
+    
+    life_support* system = PyObject_New(life_support, &life_support_type);
+    if (!system)
+        return 0;
+
+    system->patient = 0;
+    
+    // We're going to leak this reference, but don't worry; the
+    // life_support system decrements it when the nurse dies.
+    PyObject* weakref = PyWeakref_NewRef(nurse, (PyObject*)system);
+
+    // weakref has either taken ownership, or we have to release it
+    // anyway
+    Py_DECREF(system);
+    if (!weakref)
+        return 0;
+    
+    system->patient = patient;
+    Py_XINCREF(patient); // hang on to the patient until death
+    return weakref;
+}
+
+}}} // namespace boost::python::objects