ceph/src/boost/boost/atomic/detail/wait_ops_windows.hpp

   1 /*
   2  * Distributed under the Boost Software License, Version 1.0.
   3  * (See accompanying file LICENSE_1_0.txt or copy at
   4  * http://www.boost.org/LICENSE_1_0.txt)
   5  *
   6  * Copyright (c) 2020 Andrey Semashev
   7  */
   8 /*!
   9  * \file   atomic/detail/wait_ops_windows.hpp
  10  *
  11  * This header contains implementation of the waiting/notifying atomic operations on Windows.
  12  */
  13
  14 #ifndef BOOST_ATOMIC_DETAIL_WAIT_OPS_WINDOWS_HPP_INCLUDED_
  15 #define BOOST_ATOMIC_DETAIL_WAIT_OPS_WINDOWS_HPP_INCLUDED_
  16
  17 #include <cstddef>
  18 #include <boost/static_assert.hpp>
  19 #include <boost/memory_order.hpp>
  20 #include <boost/winapi/basic_types.hpp>
  21 #include <boost/winapi/wait_constants.hpp>
  22 #include <boost/atomic/detail/config.hpp>
  23 #include <boost/atomic/detail/link.hpp>
  24 #include <boost/atomic/detail/once_flag.hpp>
  25 #include <boost/atomic/detail/wait_operations_fwd.hpp>
  26 #include <boost/atomic/detail/wait_ops_generic.hpp>
  27 #include <boost/atomic/detail/header.hpp>
  28
  29 #ifdef BOOST_HAS_PRAGMA_ONCE
  30 #pragma once
  31 #endif
  32
  33 namespace boost {
  34 namespace atomics {
  35 namespace detail {
  36
  37 typedef boost::winapi::BOOL_ BOOST_WINAPI_WINAPI_CC
  38 wait_on_address_t(
  39     volatile boost::winapi::VOID_* addr,
  40     boost::winapi::PVOID_ compare_addr,
  41     boost::winapi::SIZE_T_ size,
  42     boost::winapi::DWORD_ timeout_ms);
  43
  44 typedef boost::winapi::VOID_ BOOST_WINAPI_WINAPI_CC
  45 wake_by_address_t(boost::winapi::PVOID_ addr);
  46
  47 extern BOOST_ATOMIC_DECL wait_on_address_t* wait_on_address;
  48 extern BOOST_ATOMIC_DECL wake_by_address_t* wake_by_address_single;
  49 extern BOOST_ATOMIC_DECL wake_by_address_t* wake_by_address_all;
  50
  51 extern BOOST_ATOMIC_DECL once_flag wait_functions_once_flag;
  52 BOOST_ATOMIC_DECL void initialize_wait_functions() BOOST_NOEXCEPT;
  53
  54 BOOST_FORCEINLINE void ensure_wait_functions_initialized() BOOST_NOEXCEPT
  55 {
  56     BOOST_STATIC_ASSERT_MSG(once_flag_operations::is_always_lock_free, "Boost.Atomic unsupported target platform: native atomic operations not implemented for bytes");
  57     if (BOOST_LIKELY(once_flag_operations::load(wait_functions_once_flag.m_flag, boost::memory_order_acquire) == 0u))
  58         return;
  59
  60     initialize_wait_functions();
  61 }
  62
  63 template< typename Base, std::size_t Size >
  64 struct wait_operations_windows :
  65     public atomics::detail::wait_operations_generic< Base, false >
  66 {
  67     typedef atomics::detail::wait_operations_generic< Base, false > base_type;
  68     typedef typename base_type::storage_type storage_type;
  69
  70     static BOOST_CONSTEXPR_OR_CONST bool always_has_native_wait_notify = false;
  71
  72     static BOOST_FORCEINLINE bool has_native_wait_notify(storage_type const volatile&) BOOST_NOEXCEPT
  73     {
  74         ensure_wait_functions_initialized();
  75         return atomics::detail::wait_on_address != NULL;
  76     }
  77
  78     static BOOST_FORCEINLINE storage_type wait(storage_type const volatile& storage, storage_type old_val, memory_order order) BOOST_NOEXCEPT
  79     {
  80         ensure_wait_functions_initialized();
  81
  82         if (BOOST_LIKELY(atomics::detail::wait_on_address != NULL))
  83         {
  84             storage_type new_val = base_type::load(storage, order);
  85             while (new_val == old_val)
  86             {
  87                 atomics::detail::wait_on_address(const_cast< storage_type* >(&storage), &old_val, Size, boost::winapi::infinite);
  88                 new_val = base_type::load(storage, order);
  89             }
  90
  91             return new_val;
  92         }
  93         else
  94         {
  95             return base_type::wait(storage, old_val, order);
  96         }
  97     }
  98
  99     static BOOST_FORCEINLINE void notify_one(storage_type volatile& storage) BOOST_NOEXCEPT
 100     {
 101         ensure_wait_functions_initialized();
 102
 103         if (BOOST_LIKELY(atomics::detail::wake_by_address_single != NULL))
 104             atomics::detail::wake_by_address_single(const_cast< storage_type* >(&storage));
 105         else
 106             base_type::notify_one(storage);
 107     }
 108
 109     static BOOST_FORCEINLINE void notify_all(storage_type volatile& storage) BOOST_NOEXCEPT
 110     {
 111         ensure_wait_functions_initialized();
 112
 113         if (BOOST_LIKELY(atomics::detail::wake_by_address_all != NULL))
 114             atomics::detail::wake_by_address_all(const_cast< storage_type* >(&storage));
 115         else
 116             base_type::notify_all(storage);
 117     }
 118 };
 119
 120 template< typename Base >
 121 struct wait_operations< Base, 1u, true, false > :
 122     public wait_operations_windows< Base, 1u >
 123 {
 124 };
 125
 126 template< typename Base >
 127 struct wait_operations< Base, 2u, true, false > :
 128     public wait_operations_windows< Base, 2u >
 129 {
 130 };
 131
 132 template< typename Base >
 133 struct wait_operations< Base, 4u, true, false > :
 134     public wait_operations_windows< Base, 4u >
 135 {
 136 };
 137
 138 template< typename Base >
 139 struct wait_operations< Base, 8u, true, false > :
 140     public wait_operations_windows< Base, 8u >
 141 {
 142 };
 143
 144 } // namespace detail
 145 } // namespace atomics
 146 } // namespace boost
 147
 148 #include <boost/atomic/detail/footer.hpp>
 149
 150 #endif // BOOST_ATOMIC_DETAIL_WAIT_OPS_WINDOWS_HPP_INCLUDED_