ceph/src/boost/boost/atomic/detail/atomic_flag_impl.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) 2011 Helge Bahmann
   7  * Copyright (c) 2013 Tim Blechmann
   8  * Copyright (c) 2014, 2020 Andrey Semashev
   9  */
  10 /*!
  11  * \file   atomic/detail/atomic_flag_impl.hpp
  12  *
  13  * This header contains implementation of \c atomic_flag.
  14  */
  15
  16 #ifndef BOOST_ATOMIC_DETAIL_ATOMIC_FLAG_IMPL_HPP_INCLUDED_
  17 #define BOOST_ATOMIC_DETAIL_ATOMIC_FLAG_IMPL_HPP_INCLUDED_
  18
  19 #include <boost/assert.hpp>
  20 #include <boost/memory_order.hpp>
  21 #include <boost/atomic/detail/config.hpp>
  22 #include <boost/atomic/detail/core_operations.hpp>
  23 #include <boost/atomic/detail/wait_operations.hpp>
  24 #include <boost/atomic/detail/aligned_variable.hpp>
  25 #include <boost/atomic/detail/header.hpp>
  26
  27 #ifdef BOOST_HAS_PRAGMA_ONCE
  28 #pragma once
  29 #endif
  30
  31 /*
  32  * IMPLEMENTATION NOTE: All interface functions MUST be declared with BOOST_FORCEINLINE,
  33  *                      see comment for convert_memory_order_to_gcc in gcc_atomic_memory_order_utils.hpp.
  34  */
  35
  36 namespace boost {
  37 namespace atomics {
  38 namespace detail {
  39
  40 #if defined(BOOST_ATOMIC_DETAIL_NO_CXX11_CONSTEXPR_UNION_INIT) || defined(BOOST_NO_CXX11_UNIFIED_INITIALIZATION_SYNTAX)
  41 #define BOOST_ATOMIC_NO_ATOMIC_FLAG_INIT
  42 #else
  43 #define BOOST_ATOMIC_FLAG_INIT {}
  44 #endif
  45
  46 //! Atomic flag implementation
  47 template< bool IsInterprocess >
  48 struct atomic_flag_impl
  49 {
  50     // Prefer 4-byte storage as most platforms support waiting/notifying operations without a lock pool for 32-bit integers
  51     typedef atomics::detail::core_operations< 4u, false, IsInterprocess > core_operations;
  52     typedef atomics::detail::wait_operations< core_operations > wait_operations;
  53     typedef typename core_operations::storage_type storage_type;
  54
  55     static BOOST_CONSTEXPR_OR_CONST bool is_always_lock_free = core_operations::is_always_lock_free;
  56     static BOOST_CONSTEXPR_OR_CONST bool always_has_native_wait_notify = wait_operations::always_has_native_wait_notify;
  57
  58     BOOST_ATOMIC_DETAIL_ALIGNED_VAR_TPL(core_operations::storage_alignment, storage_type, m_storage);
  59
  60     BOOST_FORCEINLINE BOOST_ATOMIC_DETAIL_CONSTEXPR_UNION_INIT atomic_flag_impl() BOOST_NOEXCEPT : m_storage(0u)
  61     {
  62     }
  63
  64     BOOST_FORCEINLINE bool is_lock_free() const volatile BOOST_NOEXCEPT
  65     {
  66         return is_always_lock_free;
  67     }
  68
  69     BOOST_FORCEINLINE bool has_native_wait_notify() const volatile BOOST_NOEXCEPT
  70     {
  71         return wait_operations::has_native_wait_notify(m_storage);
  72     }
  73
  74     BOOST_FORCEINLINE bool test(memory_order order = memory_order_seq_cst) const volatile BOOST_NOEXCEPT
  75     {
  76         BOOST_ASSERT(order != memory_order_release);
  77         BOOST_ASSERT(order != memory_order_acq_rel);
  78         return !!core_operations::load(m_storage, order);
  79     }
  80
  81     BOOST_FORCEINLINE bool test_and_set(memory_order order = memory_order_seq_cst) volatile BOOST_NOEXCEPT
  82     {
  83         return core_operations::test_and_set(m_storage, order);
  84     }
  85
  86     BOOST_FORCEINLINE void clear(memory_order order = memory_order_seq_cst) volatile BOOST_NOEXCEPT
  87     {
  88         BOOST_ASSERT(order != memory_order_consume);
  89         BOOST_ASSERT(order != memory_order_acquire);
  90         BOOST_ASSERT(order != memory_order_acq_rel);
  91         core_operations::clear(m_storage, order);
  92     }
  93
  94     BOOST_FORCEINLINE bool wait(bool old_val, memory_order order = memory_order_seq_cst) const volatile BOOST_NOEXCEPT
  95     {
  96         BOOST_ASSERT(order != memory_order_release);
  97         BOOST_ASSERT(order != memory_order_acq_rel);
  98
  99         return !!wait_operations::wait(m_storage, static_cast< storage_type >(old_val), order);
 100     }
 101
 102     BOOST_FORCEINLINE void notify_one() volatile BOOST_NOEXCEPT
 103     {
 104         wait_operations::notify_one(m_storage);
 105     }
 106
 107     BOOST_FORCEINLINE void notify_all() volatile BOOST_NOEXCEPT
 108     {
 109         wait_operations::notify_all(m_storage);
 110     }
 111
 112     BOOST_DELETED_FUNCTION(atomic_flag_impl(atomic_flag_impl const&))
 113     BOOST_DELETED_FUNCTION(atomic_flag_impl& operator= (atomic_flag_impl const&))
 114 };
 115
 116 #if defined(BOOST_NO_CXX17_INLINE_VARIABLES)
 117 template< bool IsInterprocess >
 118 BOOST_CONSTEXPR_OR_CONST bool atomic_flag_impl< IsInterprocess >::is_always_lock_free;
 119 template< bool IsInterprocess >
 120 BOOST_CONSTEXPR_OR_CONST bool atomic_flag_impl< IsInterprocess >::always_has_native_wait_notify;
 121 #endif
 122
 123 } // namespace detail
 124 } // namespace atomics
 125 } // namespace boost
 126
 127 #include <boost/atomic/detail/footer.hpp>
 128
 129 #endif // BOOST_ATOMIC_DETAIL_ATOMIC_FLAG_IMPL_HPP_INCLUDED_