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1 | /* | |
2 | * Copyright Andrey Semashev 2007 - 2015. | |
3 | * Distributed under the Boost Software License, Version 1.0. | |
4 | * (See accompanying file LICENSE_1_0.txt or copy at | |
5 | * http://www.boost.org/LICENSE_1_0.txt) | |
6 | */ | |
7 | /*! | |
8 | * \file attribute_cast.hpp | |
9 | * \author Andrey Semashev | |
10 | * \date 06.08.2010 | |
11 | * | |
12 | * The header contains utilities for casting between attribute factories. | |
13 | */ | |
14 | ||
15 | #ifndef BOOST_LOG_ATTRIBUTES_ATTRIBUTE_CAST_HPP_INCLUDED_ | |
16 | #define BOOST_LOG_ATTRIBUTES_ATTRIBUTE_CAST_HPP_INCLUDED_ | |
17 | ||
18 | #include <boost/log/detail/config.hpp> | |
19 | #include <boost/log/attributes/attribute.hpp> | |
20 | #include <boost/log/detail/header.hpp> | |
21 | ||
22 | #ifdef BOOST_HAS_PRAGMA_ONCE | |
23 | #pragma once | |
24 | #endif | |
25 | ||
26 | namespace boost { | |
27 | ||
28 | BOOST_LOG_OPEN_NAMESPACE | |
29 | ||
30 | namespace attributes { | |
31 | ||
32 | /*! | |
33 | * The class holds a reference to the attribute factory implementation being casted | |
34 | */ | |
35 | class cast_source | |
36 | { | |
37 | private: | |
38 | attribute::impl* m_pImpl; | |
39 | ||
40 | public: | |
41 | /*! | |
42 | * Initializing constructor. Creates a source that refers to the specified factory implementation. | |
43 | */ | |
44 | explicit cast_source(attribute::impl* p) : m_pImpl(p) | |
45 | { | |
46 | } | |
47 | ||
48 | /*! | |
49 | * The function attempts to cast the aggregated pointer to the implementation to the specified type. | |
50 | * | |
51 | * \return The converted pointer or \c NULL, if the conversion fails. | |
52 | */ | |
53 | template< typename T > | |
54 | T* as() const { return dynamic_cast< T* >(m_pImpl); } | |
55 | }; | |
56 | ||
57 | } // namespace attributes | |
58 | ||
59 | /*! | |
60 | * The function casts one attribute factory to another | |
61 | */ | |
62 | template< typename T > | |
63 | inline T attribute_cast(attribute const& attr) | |
64 | { | |
65 | return T(attributes::cast_source(attr.get_impl())); | |
66 | } | |
67 | ||
68 | BOOST_LOG_CLOSE_NAMESPACE // namespace log | |
69 | ||
70 | } // namespace boost | |
71 | ||
72 | #include <boost/log/detail/footer.hpp> | |
73 | ||
74 | #endif // BOOST_LOG_ATTRIBUTES_ATTRIBUTE_CAST_HPP_INCLUDED_ |