mirror of git://gcc.gnu.org/git/gcc.git
416 lines
10 KiB
C++
416 lines
10 KiB
C++
// <thread> -*- C++ -*-
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// Copyright (C) 2008-2016 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file include/thread
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* This is a Standard C++ Library header.
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*/
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#ifndef _GLIBCXX_THREAD
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#define _GLIBCXX_THREAD 1
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#pragma GCC system_header
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#if __cplusplus < 201103L
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# include <bits/c++0x_warning.h>
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#else
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#include <chrono>
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#include <memory>
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#include <tuple>
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#include <cerrno>
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#include <bits/functexcept.h>
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#include <bits/functional_hash.h>
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#include <bits/invoke.h>
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#include <bits/gthr.h>
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#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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/**
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* @defgroup threads Threads
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* @ingroup concurrency
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*
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* Classes for thread support.
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* @{
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*/
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/// thread
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class thread
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{
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public:
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// Abstract base class for types that wrap arbitrary functors to be
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// invoked in the new thread of execution.
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struct _State
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{
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virtual ~_State();
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virtual void _M_run() = 0;
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};
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using _State_ptr = unique_ptr<_State>;
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typedef __gthread_t native_handle_type;
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/// thread::id
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class id
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{
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native_handle_type _M_thread;
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public:
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id() noexcept : _M_thread() { }
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explicit
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id(native_handle_type __id) : _M_thread(__id) { }
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private:
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friend class thread;
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friend class hash<thread::id>;
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friend bool
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operator==(thread::id __x, thread::id __y) noexcept;
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friend bool
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operator<(thread::id __x, thread::id __y) noexcept;
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template<class _CharT, class _Traits>
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friend basic_ostream<_CharT, _Traits>&
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operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id);
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};
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private:
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id _M_id;
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public:
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thread() noexcept = default;
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// _GLIBCXX_RESOLVE_LIB_DEFECTS
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// 2097. packaged_task constructors should be constrained
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thread(thread&) = delete;
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thread(const thread&) = delete;
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thread(thread&& __t) noexcept
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{ swap(__t); }
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template<typename _Callable, typename... _Args>
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explicit
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thread(_Callable&& __f, _Args&&... __args)
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{
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#ifdef GTHR_ACTIVE_PROXY
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// Create a reference to pthread_create, not just the gthr weak symbol.
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auto __depend = reinterpret_cast<void(*)()>(&pthread_create);
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#else
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auto __depend = nullptr;
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#endif
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_M_start_thread(_S_make_state(
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__make_invoker(std::forward<_Callable>(__f),
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std::forward<_Args>(__args)...)),
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__depend);
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}
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~thread()
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{
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if (joinable())
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std::terminate();
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}
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thread& operator=(const thread&) = delete;
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thread& operator=(thread&& __t) noexcept
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{
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if (joinable())
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std::terminate();
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swap(__t);
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return *this;
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}
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void
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swap(thread& __t) noexcept
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{ std::swap(_M_id, __t._M_id); }
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bool
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joinable() const noexcept
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{ return !(_M_id == id()); }
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void
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join();
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void
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detach();
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thread::id
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get_id() const noexcept
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{ return _M_id; }
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/** @pre thread is joinable
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*/
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native_handle_type
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native_handle()
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{ return _M_id._M_thread; }
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// Returns a value that hints at the number of hardware thread contexts.
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static unsigned int
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hardware_concurrency() noexcept;
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private:
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template<typename _Callable>
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struct _State_impl : public _State
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{
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_Callable _M_func;
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_State_impl(_Callable&& __f) : _M_func(std::forward<_Callable>(__f))
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{ }
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void
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_M_run() { _M_func(); }
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};
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void
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_M_start_thread(_State_ptr, void (*)());
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template<typename _Callable>
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static _State_ptr
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_S_make_state(_Callable&& __f)
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{
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using _Impl = _State_impl<_Callable>;
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return _State_ptr{new _Impl{std::forward<_Callable>(__f)}};
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}
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#if _GLIBCXX_THREAD_ABI_COMPAT
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public:
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struct _Impl_base;
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typedef shared_ptr<_Impl_base> __shared_base_type;
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struct _Impl_base
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{
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__shared_base_type _M_this_ptr;
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virtual ~_Impl_base() = default;
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virtual void _M_run() = 0;
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};
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private:
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void
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_M_start_thread(__shared_base_type, void (*)());
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void
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_M_start_thread(__shared_base_type);
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#endif
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private:
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// A call wrapper that does INVOKE(forwarded tuple elements...)
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template<typename _Tuple>
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struct _Invoker
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{
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_Tuple _M_t;
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template<size_t _Index>
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static __tuple_element_t<_Index, _Tuple>&&
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_S_declval();
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template<size_t... _Ind>
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auto
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_M_invoke(_Index_tuple<_Ind...>)
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noexcept(noexcept(std::__invoke(_S_declval<_Ind>()...)))
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-> decltype(std::__invoke(_S_declval<_Ind>()...))
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{ return std::__invoke(std::get<_Ind>(std::move(_M_t))...); }
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using _Indices
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= typename _Build_index_tuple<tuple_size<_Tuple>::value>::__type;
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using result_type
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= decltype(std::declval<_Invoker>()._M_invoke(_Indices()));
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result_type
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operator()()
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noexcept(noexcept(std::declval<_Invoker>()._M_invoke(_Indices())))
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{ return _M_invoke(_Indices()); }
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};
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// Alias for _Invoker<tuple<DECAY_COPY(_Tp)...>>
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template<typename... _Tp>
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using __invoker_type
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= _Invoker<decltype(std::make_tuple(std::declval<_Tp>()...))>;
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public:
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// Returns a call wrapper that does
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// INVOKE(DECAY_COPY(__callable), DECAY_COPY(__args)).
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template<typename _Callable, typename... _Args>
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static __invoker_type<_Callable, _Args...>
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__make_invoker(_Callable&& __callable, _Args&&... __args)
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{
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return { {
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std::make_tuple(std::forward<_Callable>(__callable),
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std::forward<_Args>(__args)...)
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} };
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}
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};
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inline void
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swap(thread& __x, thread& __y) noexcept
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{ __x.swap(__y); }
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inline bool
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operator==(thread::id __x, thread::id __y) noexcept
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{
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// pthread_equal is undefined if either thread ID is not valid, so we
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// can't safely use __gthread_equal on default-constructed values (nor
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// the non-zero value returned by this_thread::get_id() for
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// single-threaded programs using GNU libc). Assume EqualityComparable.
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return __x._M_thread == __y._M_thread;
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}
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inline bool
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operator!=(thread::id __x, thread::id __y) noexcept
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{ return !(__x == __y); }
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inline bool
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operator<(thread::id __x, thread::id __y) noexcept
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{
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// Pthreads doesn't define any way to do this, so we just have to
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// assume native_handle_type is LessThanComparable.
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return __x._M_thread < __y._M_thread;
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}
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inline bool
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operator<=(thread::id __x, thread::id __y) noexcept
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{ return !(__y < __x); }
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inline bool
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operator>(thread::id __x, thread::id __y) noexcept
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{ return __y < __x; }
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inline bool
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operator>=(thread::id __x, thread::id __y) noexcept
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{ return !(__x < __y); }
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// DR 889.
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/// std::hash specialization for thread::id.
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template<>
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struct hash<thread::id>
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: public __hash_base<size_t, thread::id>
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{
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size_t
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operator()(const thread::id& __id) const noexcept
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{ return std::_Hash_impl::hash(__id._M_thread); }
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};
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template<class _CharT, class _Traits>
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inline basic_ostream<_CharT, _Traits>&
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operator<<(basic_ostream<_CharT, _Traits>& __out, thread::id __id)
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{
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if (__id == thread::id())
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return __out << "thread::id of a non-executing thread";
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else
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return __out << __id._M_thread;
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}
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_GLIBCXX_END_NAMESPACE_VERSION
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/** @namespace std::this_thread
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* @brief ISO C++ 2011 entities sub-namespace for thread.
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* 30.3.2 Namespace this_thread.
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*/
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namespace this_thread
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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/// get_id
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inline thread::id
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get_id() noexcept
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{
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#ifdef __GLIBC__
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// For the GNU C library pthread_self() is usable without linking to
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// libpthread.so but returns 0, so we cannot use it in single-threaded
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// programs, because this_thread::get_id() != thread::id{} must be true.
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// We know that pthread_t is an integral type in the GNU C library.
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if (!__gthread_active_p())
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return thread::id(1);
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#endif
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return thread::id(__gthread_self());
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}
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/// yield
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inline void
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yield() noexcept
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{
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#ifdef _GLIBCXX_USE_SCHED_YIELD
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__gthread_yield();
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#endif
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}
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void
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__sleep_for(chrono::seconds, chrono::nanoseconds);
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/// sleep_for
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template<typename _Rep, typename _Period>
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inline void
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sleep_for(const chrono::duration<_Rep, _Period>& __rtime)
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{
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if (__rtime <= __rtime.zero())
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return;
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auto __s = chrono::duration_cast<chrono::seconds>(__rtime);
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auto __ns = chrono::duration_cast<chrono::nanoseconds>(__rtime - __s);
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#ifdef _GLIBCXX_USE_NANOSLEEP
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__gthread_time_t __ts =
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{
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static_cast<std::time_t>(__s.count()),
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static_cast<long>(__ns.count())
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};
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while (::nanosleep(&__ts, &__ts) == -1 && errno == EINTR)
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{ }
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#else
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__sleep_for(__s, __ns);
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#endif
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}
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/// sleep_until
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template<typename _Clock, typename _Duration>
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inline void
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sleep_until(const chrono::time_point<_Clock, _Duration>& __atime)
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{
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auto __now = _Clock::now();
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if (_Clock::is_steady)
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{
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if (__now < __atime)
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sleep_for(__atime - __now);
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return;
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}
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while (__now < __atime)
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{
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sleep_for(__atime - __now);
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__now = _Clock::now();
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}
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}
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_GLIBCXX_END_NAMESPACE_VERSION
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}
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// @} group threads
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} // namespace
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#endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
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#endif // C++11
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#endif // _GLIBCXX_THREAD
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