| 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 thread_specific.hpp |
| 9 | * \author Andrey Semashev |
| 10 | * \date 01.03.2008 |
| 11 | * |
| 12 | * \brief This header is the Boost.Log library implementation, see the library documentation |
| 13 | * at http://www.boost.org/doc/libs/release/libs/log/doc/html/index.html. |
| 14 | */ |
| 15 | |
| 16 | #ifndef BOOST_LOG_DETAIL_THREAD_SPECIFIC_HPP_INCLUDED_ |
| 17 | #define BOOST_LOG_DETAIL_THREAD_SPECIFIC_HPP_INCLUDED_ |
| 18 | |
| 19 | #include <boost/type_traits/is_pod.hpp> |
| 20 | #include <boost/log/detail/config.hpp> |
| 21 | |
| 22 | #ifdef BOOST_HAS_PRAGMA_ONCE |
| 23 | #pragma once |
| 24 | #endif |
| 25 | |
| 26 | #if !defined(BOOST_LOG_NO_THREADS) |
| 27 | |
| 28 | #include <boost/log/detail/header.hpp> |
| 29 | |
| 30 | namespace boost { |
| 31 | |
| 32 | BOOST_LOG_OPEN_NAMESPACE |
| 33 | |
| 34 | namespace aux { |
| 35 | |
| 36 | //! Base class for TLS to hide platform-specific storage management |
| 37 | class thread_specific_base |
| 38 | { |
| 39 | private: |
| 40 | #if defined(BOOST_THREAD_PLATFORM_WIN32) |
| 41 | typedef unsigned long key_storage; |
| 42 | #else |
| 43 | typedef void* key_storage; |
| 44 | #endif |
| 45 | |
| 46 | key_storage m_Key; |
| 47 | |
| 48 | protected: |
| 49 | BOOST_LOG_API thread_specific_base(); |
| 50 | BOOST_LOG_API ~thread_specific_base(); |
| 51 | BOOST_LOG_API void* get_content() const; |
| 52 | BOOST_LOG_API void set_content(void* value) const; |
| 53 | |
| 54 | // Copying prohibited |
| 55 | BOOST_DELETED_FUNCTION(thread_specific_base(thread_specific_base const&)) |
| 56 | BOOST_DELETED_FUNCTION(thread_specific_base& operator= (thread_specific_base const&)) |
| 57 | }; |
| 58 | |
| 59 | //! A TLS wrapper for small POD types with least possible overhead |
| 60 | template< typename T > |
| 61 | class thread_specific : |
| 62 | public thread_specific_base |
| 63 | { |
| 64 | static_assert(sizeof(T) <= sizeof(void*) && is_pod< T >::value, "Boost.Log: Thread-specific values must be PODs and must not exceed the size of a pointer"); |
| 65 | |
| 66 | //! Union to perform type casting |
| 67 | union value_storage |
| 68 | { |
| 69 | void* as_pointer; |
| 70 | T as_value; |
| 71 | }; |
| 72 | |
| 73 | public: |
| 74 | //! Default constructor |
| 75 | BOOST_DEFAULTED_FUNCTION(thread_specific(), {}) |
| 76 | //! Initializing constructor |
| 77 | thread_specific(T const& value) |
| 78 | { |
| 79 | set(value); |
| 80 | } |
| 81 | //! Assignment |
| 82 | thread_specific& operator= (T const& value) |
| 83 | { |
| 84 | set(value); |
| 85 | return *this; |
| 86 | } |
| 87 | |
| 88 | //! Accessor |
| 89 | T get() const |
| 90 | { |
| 91 | value_storage cast = {}; |
| 92 | cast.as_pointer = thread_specific_base::get_content(); |
| 93 | return cast.as_value; |
| 94 | } |
| 95 | |
| 96 | //! Setter |
| 97 | void set(T const& value) |
| 98 | { |
| 99 | value_storage cast = {}; |
| 100 | cast.as_value = value; |
| 101 | thread_specific_base::set_content(cast.as_pointer); |
| 102 | } |
| 103 | }; |
| 104 | |
| 105 | } // namespace aux |
| 106 | |
| 107 | BOOST_LOG_CLOSE_NAMESPACE // namespace log |
| 108 | |
| 109 | } // namespace boost |
| 110 | |
| 111 | #include <boost/log/detail/footer.hpp> |
| 112 | |
| 113 | #endif // !defined(BOOST_LOG_NO_THREADS) |
| 114 | |
| 115 | #endif // BOOST_LOG_DETAIL_THREAD_SPECIFIC_HPP_INCLUDED_ |
| 116 |