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 | #ifndef WITH_CUSTODIAN_AND_WARD_DWA2002131_HPP |
6 | # define WITH_CUSTODIAN_AND_WARD_DWA2002131_HPP |
7 | |
8 | # include <boost/python/detail/prefix.hpp> |
9 | |
10 | # include <boost/python/default_call_policies.hpp> |
11 | # include <boost/python/object/life_support.hpp> |
12 | # include <algorithm> |
13 | |
14 | namespace boost { namespace python { |
15 | |
16 | namespace detail |
17 | { |
18 | template <std::size_t N> |
19 | struct get_prev |
20 | { |
21 | template <class ArgumentPackage> |
22 | static PyObject* execute(ArgumentPackage const& args, PyObject* = 0) |
23 | { |
24 | int const pre_n = static_cast<int>(N) - 1; // separate line is gcc-2.96 workaround |
25 | return detail::get(mpl::int_<pre_n>(), args); |
26 | } |
27 | }; |
28 | template <> |
29 | struct get_prev<0> |
30 | { |
31 | template <class ArgumentPackage> |
32 | static PyObject* execute(ArgumentPackage const&, PyObject* zeroth) |
33 | { |
34 | return zeroth; |
35 | } |
36 | }; |
37 | } |
38 | template < |
39 | std::size_t custodian |
40 | , std::size_t ward |
41 | , class BasePolicy_ = default_call_policies |
42 | > |
43 | struct with_custodian_and_ward : BasePolicy_ |
44 | { |
45 | BOOST_STATIC_ASSERT(custodian != ward); |
46 | BOOST_STATIC_ASSERT(custodian > 0); |
47 | BOOST_STATIC_ASSERT(ward > 0); |
48 | |
49 | template <class ArgumentPackage> |
50 | static bool precall(ArgumentPackage const& args_) |
51 | { |
52 | unsigned arity_ = detail::arity(args_); |
53 | if (custodian > arity_ || ward > arity_) |
54 | { |
55 | PyErr_SetString( |
56 | PyExc_IndexError |
57 | , "boost::python::with_custodian_and_ward: argument index out of range" |
58 | ); |
59 | return false; |
60 | } |
61 | |
62 | PyObject* patient = detail::get_prev<ward>::execute(args_); |
63 | PyObject* nurse = detail::get_prev<custodian>::execute(args_); |
64 | |
65 | PyObject* life_support = python::objects::make_nurse_and_patient(nurse, patient); |
66 | if (life_support == 0) |
67 | return false; |
68 | |
69 | bool result = BasePolicy_::precall(args_); |
70 | |
71 | if (!result) { |
72 | Py_DECREF(life_support); |
73 | } |
74 | |
75 | return result; |
76 | } |
77 | }; |
78 | |
79 | template <std::size_t custodian, std::size_t ward, class BasePolicy_ = default_call_policies> |
80 | struct with_custodian_and_ward_postcall : BasePolicy_ |
81 | { |
82 | BOOST_STATIC_ASSERT(custodian != ward); |
83 | |
84 | template <class ArgumentPackage> |
85 | static PyObject* postcall(ArgumentPackage const& args_, PyObject* result) |
86 | { |
87 | std::size_t arity_ = detail::arity(args_); |
88 | // check if either custodian or ward exceeds the arity |
89 | // (this weird formulation avoids "always false" warnings |
90 | // for arity_ = 0) |
91 | if ( (std::max)(a: custodian, b: ward) > arity_ ) |
92 | { |
93 | PyErr_SetString( |
94 | PyExc_IndexError |
95 | , "boost::python::with_custodian_and_ward_postcall: argument index out of range" |
96 | ); |
97 | return 0; |
98 | } |
99 | |
100 | PyObject* patient = detail::get_prev<ward>::execute(args_, result); |
101 | PyObject* nurse = detail::get_prev<custodian>::execute(args_, result); |
102 | |
103 | if (nurse == 0) return 0; |
104 | |
105 | result = BasePolicy_::postcall(args_, result); |
106 | if (result == 0) |
107 | return 0; |
108 | |
109 | if (python::objects::make_nurse_and_patient(nurse, patient) == 0) |
110 | { |
111 | Py_XDECREF(result); |
112 | return 0; |
113 | } |
114 | return result; |
115 | } |
116 | }; |
117 | |
118 | |
119 | }} // namespace boost::python |
120 | |
121 | #endif // WITH_CUSTODIAN_AND_WARD_DWA2002131_HPP |
122 | |