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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 DATA_MEMBERS_DWA2002328_HPP | |
6 | # define DATA_MEMBERS_DWA2002328_HPP | |
7 | ||
8 | # include <boost/python/detail/prefix.hpp> | |
9 | ||
10 | # include <boost/python/handle.hpp> | |
11 | ||
12 | # include <boost/python/return_value_policy.hpp> | |
13 | # include <boost/python/return_by_value.hpp> | |
14 | # include <boost/python/return_internal_reference.hpp> | |
15 | # include <boost/python/make_function.hpp> | |
16 | ||
17 | # include <boost/python/converter/builtin_converters.hpp> | |
18 | ||
19 | # include <boost/python/detail/indirect_traits.hpp> | |
20 | # include <boost/python/detail/not_specified.hpp> | |
21 | # include <boost/python/detail/value_arg.hpp> | |
22 | ||
23 | # include <boost/type_traits/add_const.hpp> | |
24 | # include <boost/type_traits/add_reference.hpp> | |
25 | # include <boost/type_traits/is_member_pointer.hpp> | |
26 | ||
27 | # if BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003)) | |
28 | # include <boost/type_traits/remove_cv.hpp> | |
29 | # endif | |
30 | ||
31 | # include <boost/mpl/eval_if.hpp> | |
32 | # include <boost/mpl/if.hpp> | |
33 | # include <boost/mpl/vector/vector10.hpp> | |
34 | ||
35 | # include <boost/detail/workaround.hpp> | |
36 | ||
37 | namespace boost { namespace python { | |
38 | ||
39 | // | |
40 | // This file defines the make_getter and make_setter function | |
41 | // families, which are responsible for turning pointers, references, | |
42 | // and pointers-to-data-members into callable Python objects which | |
43 | // can be used for attribute access on wrapped classes. | |
44 | // | |
45 | ||
46 | namespace detail | |
47 | { | |
48 | ||
49 | // A small function object which handles the getting and setting of | |
50 | // data members. | |
51 | template <class Data, class Class> | |
52 | struct member | |
53 | { | |
54 | public: | |
55 | member(Data Class::*which) : m_which(which) {} | |
56 | ||
57 | Data& operator()(Class& c) const | |
58 | { | |
59 | return c.*m_which; | |
60 | } | |
61 | ||
62 | void operator()(Class& c, typename value_arg<Data>::type d) const | |
63 | { | |
64 | c.*m_which = d; | |
65 | } | |
66 | private: | |
67 | Data Class::*m_which; | |
68 | }; | |
69 | ||
70 | // A small function object which handles the getting and setting of | |
71 | // non-member objects. | |
72 | template <class Data> | |
73 | struct datum | |
74 | { | |
75 | public: | |
76 | datum(Data *which) : m_which(which) {} | |
77 | ||
78 | Data& operator()() const | |
79 | { | |
80 | return *m_which; | |
81 | } | |
82 | ||
83 | void operator()(typename value_arg<Data>::type d) const | |
84 | { | |
85 | *m_which = d; | |
86 | } | |
87 | private: | |
88 | Data *m_which; | |
89 | }; | |
90 | ||
91 | // | |
92 | // Helper metafunction for determining the default CallPolicy to use | |
93 | // for attribute access. If T is a [reference to a] class type X | |
94 | // whose conversion to python would normally produce a new copy of X | |
95 | // in a wrapped X class instance (as opposed to types such as | |
96 | // std::string, which are converted to native Python types, and | |
97 | // smart pointer types which produce a wrapped class instance of the | |
98 | // pointee type), to-python conversions will attempt to produce an | |
99 | // object which refers to the original C++ object, rather than a | |
100 | // copy. See default_member_getter_policy for rationale. | |
101 | // | |
102 | template <class T> | |
103 | struct default_getter_by_ref | |
104 | : mpl::and_< | |
105 | mpl::bool_< | |
106 | to_python_value< | |
107 | typename value_arg<T>::type | |
108 | >::uses_registry | |
109 | > | |
110 | , indirect_traits::is_reference_to_class< | |
111 | typename value_arg<T>::type | |
112 | > | |
113 | > | |
114 | { | |
115 | }; | |
116 | ||
117 | // Metafunction computing the default CallPolicy to use for reading | |
118 | // data members | |
119 | // | |
120 | // If it's a regular class type (not an object manager or other | |
121 | // type for which we have to_python specializations, use | |
122 | // return_internal_reference so that we can do things like | |
123 | // x.y.z = 1 | |
124 | // and get the right result. | |
125 | template <class T> | |
126 | struct default_member_getter_policy | |
127 | : mpl::if_< | |
128 | default_getter_by_ref<T> | |
129 | , return_internal_reference<> | |
130 | , return_value_policy<return_by_value> | |
131 | > | |
132 | {}; | |
133 | ||
134 | // Metafunction computing the default CallPolicy to use for reading | |
135 | // non-member data. | |
136 | template <class T> | |
137 | struct default_datum_getter_policy | |
138 | : mpl::if_< | |
139 | default_getter_by_ref<T> | |
140 | , return_value_policy<reference_existing_object> | |
141 | , return_value_policy<return_by_value> | |
142 | > | |
143 | {}; | |
144 | ||
145 | // | |
146 | // make_getter helper function family -- These helpers to | |
147 | // boost::python::make_getter are used to dispatch behavior. The | |
148 | // third argument is a workaround for a CWPro8 partial ordering bug | |
149 | // with pointers to data members. It should be convertible to | |
150 | // mpl::true_ iff the first argument is a pointer-to-member, and | |
151 | // mpl::false_ otherwise. The fourth argument is for compilers | |
152 | // which don't support partial ordering at all and should always be | |
153 | // passed 0L. | |
154 | // | |
155 | ||
156 | #if BOOST_WORKAROUND(__EDG_VERSION__, <= 238) | |
157 | template <class D, class P> | |
158 | inline object make_getter(D& d, P& p, mpl::false_, ...); | |
159 | #endif | |
160 | ||
161 | // Handle non-member pointers with policies | |
162 | template <class D, class Policies> | |
163 | inline object make_getter(D* d, Policies const& policies, mpl::false_, int) | |
164 | { | |
165 | return python::make_function( | |
166 | detail::datum<D>(d), policies, mpl::vector1<D&>() | |
167 | ); | |
168 | } | |
169 | ||
170 | // Handle non-member pointers without policies | |
171 | template <class D> | |
172 | inline object make_getter(D* d, not_specified, mpl::false_, long) | |
173 | { | |
174 | typedef typename default_datum_getter_policy<D>::type policies; | |
175 | return detail::make_getter(d, policies(), mpl::false_(), 0); | |
176 | } | |
177 | ||
178 | // Handle pointers-to-members with policies | |
179 | template <class C, class D, class Policies> | |
180 | inline object make_getter(D C::*pm, Policies const& policies, mpl::true_, int) | |
181 | { | |
182 | #if BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003)) | |
183 | typedef typename remove_cv<C>::type Class; | |
184 | #else | |
185 | typedef C Class; | |
186 | #endif | |
187 | return python::make_function( | |
188 | detail::member<D,Class>(pm) | |
189 | , policies | |
190 | , mpl::vector2<D&,Class&>() | |
191 | ); | |
192 | } | |
193 | ||
194 | // Handle pointers-to-members without policies | |
195 | template <class C, class D> | |
196 | inline object make_getter(D C::*pm, not_specified, mpl::true_, long) | |
197 | { | |
198 | typedef typename default_member_getter_policy<D>::type policies; | |
199 | return detail::make_getter(pm, policies(), mpl::true_(), 0); | |
200 | } | |
201 | ||
202 | // Handle references | |
203 | template <class D, class P> | |
204 | inline object make_getter(D& d, P& p, mpl::false_, ...) | |
205 | { | |
206 | // Just dispatch to the handler for pointer types. | |
207 | return detail::make_getter(&d, p, mpl::false_(), 0L); | |
208 | } | |
209 | ||
210 | // | |
211 | // make_setter helper function family -- These helpers to | |
212 | // boost::python::make_setter are used to dispatch behavior. The | |
213 | // third argument is for compilers which don't support partial | |
214 | // ordering at all and should always be passed 0. | |
215 | // | |
216 | ||
217 | ||
218 | // Handle non-member pointers | |
219 | template <class D, class Policies> | |
220 | inline object make_setter(D* p, Policies const& policies, mpl::false_, int) | |
221 | { | |
222 | return python::make_function( | |
223 | detail::datum<D>(p), policies, mpl::vector2<void,D const&>() | |
224 | ); | |
225 | } | |
226 | ||
227 | // Handle pointers-to-members | |
228 | template <class C, class D, class Policies> | |
229 | inline object make_setter(D C::*pm, Policies const& policies, mpl::true_, int) | |
230 | { | |
231 | return python::make_function( | |
232 | detail::member<D,C>(pm) | |
233 | , policies | |
234 | , mpl::vector3<void, C&, D const&>() | |
235 | ); | |
236 | } | |
237 | ||
238 | // Handle references | |
239 | template <class D, class Policies> | |
240 | inline object make_setter(D& x, Policies const& policies, mpl::false_, ...) | |
241 | { | |
242 | return detail::make_setter(&x, policies, mpl::false_(), 0L); | |
243 | } | |
244 | } | |
245 | ||
246 | // | |
247 | // make_getter function family -- build a callable object which | |
248 | // retrieves data through the first argument and is appropriate for | |
249 | // use as the `get' function in Python properties . The second, | |
250 | // policies argument, is optional. We need both D& and D const& | |
251 | // overloads in order be able to handle rvalues. | |
252 | // | |
253 | template <class D, class Policies> | |
254 | inline object make_getter(D& d, Policies const& policies) | |
255 | { | |
256 | return detail::make_getter(d, policies, is_member_pointer<D>(), 0L); | |
257 | } | |
258 | ||
259 | template <class D, class Policies> | |
260 | inline object make_getter(D const& d, Policies const& policies) | |
261 | { | |
262 | return detail::make_getter(d, policies, is_member_pointer<D>(), 0L); | |
263 | } | |
264 | ||
265 | template <class D> | |
266 | inline object make_getter(D& x) | |
267 | { | |
268 | detail::not_specified policy | |
269 | = detail::not_specified(); // suppress a SunPro warning | |
270 | return detail::make_getter(x, policy, is_member_pointer<D>(), 0L); | |
271 | } | |
272 | ||
273 | # if !BOOST_WORKAROUND(__EDG_VERSION__, <= 238) | |
274 | template <class D> | |
275 | inline object make_getter(D const& d) | |
276 | { | |
277 | detail::not_specified policy | |
278 | = detail::not_specified(); // Suppress a SunPro warning | |
279 | return detail::make_getter(d, policy, is_member_pointer<D>(), 0L); | |
280 | } | |
281 | # endif | |
282 | ||
283 | // | |
284 | // make_setter function family -- build a callable object which | |
285 | // writes data through the first argument and is appropriate for | |
286 | // use as the `set' function in Python properties . The second, | |
287 | // policies argument, is optional. We need both D& and D const& | |
288 | // overloads in order be able to handle rvalues. | |
289 | // | |
290 | template <class D, class Policies> | |
291 | inline object make_setter(D& x, Policies const& policies) | |
292 | { | |
293 | return detail::make_setter(x, policies, is_member_pointer<D>(), 0); | |
294 | } | |
295 | ||
296 | template <class D, class Policies> | |
297 | inline object make_setter(D const& x, Policies const& policies) | |
298 | { | |
299 | return detail::make_setter(x, policies, is_member_pointer<D>(), 0); | |
300 | } | |
301 | ||
302 | template <class D> | |
303 | inline object make_setter(D& x) | |
304 | { | |
305 | return detail::make_setter(x, default_call_policies(), is_member_pointer<D>(), 0); | |
306 | } | |
307 | ||
308 | # if !BOOST_WORKAROUND(__EDG_VERSION__, <= 238) | |
309 | template <class D> | |
310 | inline object make_setter(D const& x) | |
311 | { | |
312 | return detail::make_setter(x, default_call_policies(), is_member_pointer<D>(), 0); | |
313 | } | |
314 | # endif | |
315 | ||
316 | }} // namespace boost::python | |
317 | ||
318 | #endif // DATA_MEMBERS_DWA2002328_HPP |