forked from KolibriOS/kolibrios
1554 lines
41 KiB
C++
1554 lines
41 KiB
C++
// <future> -*- C++ -*-
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// Copyright (C) 2009-2013 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/future
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* This is a Standard C++ Library header.
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*/
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#ifndef _GLIBCXX_FUTURE
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#define _GLIBCXX_FUTURE 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 <functional>
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#include <mutex>
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#include <thread>
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#include <condition_variable>
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#include <system_error>
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#include <atomic>
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#include <bits/functexcept.h>
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#include <bits/unique_ptr.h>
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#include <bits/shared_ptr.h>
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#include <bits/uses_allocator.h>
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#include <bits/alloc_traits.h>
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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 futures Futures
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* @ingroup concurrency
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*
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* Classes for futures support.
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* @{
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*/
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/// Error code for futures
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enum class future_errc
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{
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future_already_retrieved = 1,
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promise_already_satisfied,
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no_state,
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broken_promise
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};
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/// Specialization.
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template<>
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struct is_error_code_enum<future_errc> : public true_type { };
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/// Points to a statically-allocated object derived from error_category.
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const error_category&
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future_category() noexcept;
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/// Overload for make_error_code.
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inline error_code
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make_error_code(future_errc __errc) noexcept
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{ return error_code(static_cast<int>(__errc), future_category()); }
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/// Overload for make_error_condition.
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inline error_condition
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make_error_condition(future_errc __errc) noexcept
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{ return error_condition(static_cast<int>(__errc), future_category()); }
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/**
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* @brief Exception type thrown by futures.
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* @ingroup exceptions
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*/
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class future_error : public logic_error
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{
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error_code _M_code;
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public:
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explicit future_error(error_code __ec)
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: logic_error("std::future_error"), _M_code(__ec)
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{ }
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virtual ~future_error() noexcept;
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virtual const char*
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what() const noexcept;
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const error_code&
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code() const noexcept { return _M_code; }
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};
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// Forward declarations.
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template<typename _Res>
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class future;
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template<typename _Res>
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class shared_future;
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template<typename _Signature>
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class packaged_task;
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template<typename _Res>
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class promise;
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/// Launch code for futures
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enum class launch
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{
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async = 1,
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deferred = 2
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};
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constexpr launch operator&(launch __x, launch __y)
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{
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return static_cast<launch>(
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static_cast<int>(__x) & static_cast<int>(__y));
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}
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constexpr launch operator|(launch __x, launch __y)
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{
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return static_cast<launch>(
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static_cast<int>(__x) | static_cast<int>(__y));
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}
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constexpr launch operator^(launch __x, launch __y)
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{
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return static_cast<launch>(
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static_cast<int>(__x) ^ static_cast<int>(__y));
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}
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constexpr launch operator~(launch __x)
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{ return static_cast<launch>(~static_cast<int>(__x)); }
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inline launch& operator&=(launch& __x, launch __y)
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{ return __x = __x & __y; }
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inline launch& operator|=(launch& __x, launch __y)
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{ return __x = __x | __y; }
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inline launch& operator^=(launch& __x, launch __y)
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{ return __x = __x ^ __y; }
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/// Status code for futures
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enum class future_status
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{
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ready,
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timeout,
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deferred
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};
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template<typename _Fn, typename... _Args>
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future<typename result_of<_Fn(_Args...)>::type>
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async(launch __policy, _Fn&& __fn, _Args&&... __args);
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template<typename _Fn, typename... _Args>
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future<typename result_of<_Fn(_Args...)>::type>
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async(_Fn&& __fn, _Args&&... __args);
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#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) \
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&& (ATOMIC_INT_LOCK_FREE > 1)
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/// Base class and enclosing scope.
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struct __future_base
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{
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/// Base class for results.
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struct _Result_base
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{
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exception_ptr _M_error;
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_Result_base(const _Result_base&) = delete;
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_Result_base& operator=(const _Result_base&) = delete;
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// _M_destroy() allows derived classes to control deallocation
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virtual void _M_destroy() = 0;
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struct _Deleter
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{
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void operator()(_Result_base* __fr) const { __fr->_M_destroy(); }
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};
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protected:
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_Result_base();
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virtual ~_Result_base();
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};
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/// Result.
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template<typename _Res>
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struct _Result : _Result_base
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{
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private:
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typedef alignment_of<_Res> __a_of;
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typedef aligned_storage<sizeof(_Res), __a_of::value> __align_storage;
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typedef typename __align_storage::type __align_type;
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__align_type _M_storage;
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bool _M_initialized;
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public:
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typedef _Res result_type;
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_Result() noexcept : _M_initialized() { }
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~_Result()
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{
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if (_M_initialized)
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_M_value().~_Res();
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}
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// Return lvalue, future will add const or rvalue-reference
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_Res&
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_M_value() noexcept { return *static_cast<_Res*>(_M_addr()); }
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void
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_M_set(const _Res& __res)
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{
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::new (_M_addr()) _Res(__res);
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_M_initialized = true;
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}
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void
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_M_set(_Res&& __res)
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{
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::new (_M_addr()) _Res(std::move(__res));
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_M_initialized = true;
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}
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private:
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void _M_destroy() { delete this; }
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void* _M_addr() noexcept { return static_cast<void*>(&_M_storage); }
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};
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/// A unique_ptr based on the instantiating type.
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template<typename _Res>
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using _Ptr = unique_ptr<_Res, _Result_base::_Deleter>;
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/// Result_alloc.
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template<typename _Res, typename _Alloc>
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struct _Result_alloc final : _Result<_Res>, _Alloc
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{
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typedef typename allocator_traits<_Alloc>::template
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rebind_alloc<_Result_alloc> __allocator_type;
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explicit
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_Result_alloc(const _Alloc& __a) : _Result<_Res>(), _Alloc(__a)
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{ }
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private:
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void _M_destroy()
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{
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typedef allocator_traits<__allocator_type> __traits;
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__allocator_type __a(*this);
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__traits::destroy(__a, this);
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__traits::deallocate(__a, this, 1);
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}
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};
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template<typename _Res, typename _Allocator>
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static _Ptr<_Result_alloc<_Res, _Allocator>>
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_S_allocate_result(const _Allocator& __a)
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{
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typedef _Result_alloc<_Res, _Allocator> __result_type;
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typedef allocator_traits<typename __result_type::__allocator_type>
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__traits;
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typename __traits::allocator_type __a2(__a);
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__result_type* __p = __traits::allocate(__a2, 1);
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__try
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{
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__traits::construct(__a2, __p, __a);
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}
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__catch(...)
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{
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__traits::deallocate(__a2, __p, 1);
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__throw_exception_again;
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}
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return _Ptr<__result_type>(__p);
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}
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template<typename _Res, typename _Tp>
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static _Ptr<_Result<_Res>>
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_S_allocate_result(const std::allocator<_Tp>& __a)
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{
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return _Ptr<_Result<_Res>>(new _Result<_Res>);
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}
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/// Base class for state between a promise and one or more
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/// associated futures.
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class _State_base
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{
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typedef _Ptr<_Result_base> _Ptr_type;
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_Ptr_type _M_result;
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mutex _M_mutex;
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condition_variable _M_cond;
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atomic_flag _M_retrieved;
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once_flag _M_once;
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public:
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_State_base() noexcept : _M_result(), _M_retrieved(ATOMIC_FLAG_INIT) { }
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_State_base(const _State_base&) = delete;
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_State_base& operator=(const _State_base&) = delete;
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virtual ~_State_base();
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_Result_base&
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wait()
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{
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_M_run_deferred();
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unique_lock<mutex> __lock(_M_mutex);
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_M_cond.wait(__lock, [&] { return _M_ready(); });
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return *_M_result;
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}
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template<typename _Rep, typename _Period>
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future_status
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wait_for(const chrono::duration<_Rep, _Period>& __rel)
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{
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unique_lock<mutex> __lock(_M_mutex);
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if (_M_cond.wait_for(__lock, __rel, [&] { return _M_ready(); }))
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return future_status::ready;
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return future_status::timeout;
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}
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template<typename _Clock, typename _Duration>
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future_status
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wait_until(const chrono::time_point<_Clock, _Duration>& __abs)
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{
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unique_lock<mutex> __lock(_M_mutex);
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if (_M_cond.wait_until(__lock, __abs, [&] { return _M_ready(); }))
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return future_status::ready;
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return future_status::timeout;
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}
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void
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_M_set_result(function<_Ptr_type()> __res, bool __ignore_failure = false)
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{
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bool __set = __ignore_failure;
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// all calls to this function are serialized,
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// side-effects of invoking __res only happen once
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call_once(_M_once, &_State_base::_M_do_set, this, ref(__res),
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ref(__set));
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if (!__set)
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__throw_future_error(int(future_errc::promise_already_satisfied));
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}
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void
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_M_break_promise(_Ptr_type __res)
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{
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if (static_cast<bool>(__res))
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{
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error_code __ec(make_error_code(future_errc::broken_promise));
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__res->_M_error = copy_exception(future_error(__ec));
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{
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lock_guard<mutex> __lock(_M_mutex);
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_M_result.swap(__res);
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}
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_M_cond.notify_all();
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}
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}
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// Called when this object is passed to a future.
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void
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_M_set_retrieved_flag()
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{
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if (_M_retrieved.test_and_set())
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__throw_future_error(int(future_errc::future_already_retrieved));
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}
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template<typename _Res, typename _Arg>
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struct _Setter;
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// set lvalues
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template<typename _Res, typename _Arg>
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struct _Setter<_Res, _Arg&>
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{
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// check this is only used by promise<R>::set_value(const R&)
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// or promise<R>::set_value(R&)
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static_assert(is_same<_Res, _Arg&>::value // promise<R&>
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|| is_same<const _Res, _Arg>::value, // promise<R>
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"Invalid specialisation");
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typename promise<_Res>::_Ptr_type operator()()
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{
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_State_base::_S_check(_M_promise->_M_future);
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_M_promise->_M_storage->_M_set(_M_arg);
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return std::move(_M_promise->_M_storage);
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}
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promise<_Res>* _M_promise;
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_Arg& _M_arg;
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};
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// set rvalues
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template<typename _Res>
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struct _Setter<_Res, _Res&&>
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{
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typename promise<_Res>::_Ptr_type operator()()
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{
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_State_base::_S_check(_M_promise->_M_future);
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_M_promise->_M_storage->_M_set(std::move(_M_arg));
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return std::move(_M_promise->_M_storage);
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}
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promise<_Res>* _M_promise;
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_Res& _M_arg;
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};
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struct __exception_ptr_tag { };
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// set exceptions
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template<typename _Res>
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struct _Setter<_Res, __exception_ptr_tag>
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{
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typename promise<_Res>::_Ptr_type operator()()
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{
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_State_base::_S_check(_M_promise->_M_future);
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_M_promise->_M_storage->_M_error = _M_ex;
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return std::move(_M_promise->_M_storage);
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}
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promise<_Res>* _M_promise;
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exception_ptr& _M_ex;
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};
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template<typename _Res, typename _Arg>
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static _Setter<_Res, _Arg&&>
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__setter(promise<_Res>* __prom, _Arg&& __arg)
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{
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return _Setter<_Res, _Arg&&>{ __prom, __arg };
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}
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template<typename _Res>
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static _Setter<_Res, __exception_ptr_tag>
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__setter(exception_ptr& __ex, promise<_Res>* __prom)
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{
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return _Setter<_Res, __exception_ptr_tag>{ __prom, __ex };
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}
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static _Setter<void, void>
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__setter(promise<void>* __prom);
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template<typename _Tp>
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static void
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_S_check(const shared_ptr<_Tp>& __p)
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{
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if (!static_cast<bool>(__p))
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__throw_future_error((int)future_errc::no_state);
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}
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private:
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void
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_M_do_set(function<_Ptr_type()>& __f, bool& __set)
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{
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_Ptr_type __res = __f();
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{
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lock_guard<mutex> __lock(_M_mutex);
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_M_result.swap(__res);
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}
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_M_cond.notify_all();
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__set = true;
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}
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bool _M_ready() const noexcept { return static_cast<bool>(_M_result); }
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// Misnamed: waits for completion of async function.
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virtual void _M_run_deferred() { }
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};
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template<typename _BoundFn, typename = typename _BoundFn::result_type>
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class _Deferred_state;
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class _Async_state_common;
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template<typename _BoundFn, typename = typename _BoundFn::result_type>
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class _Async_state_impl;
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template<typename _Signature>
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class _Task_state_base;
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template<typename _Fn, typename _Alloc, typename _Signature>
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class _Task_state;
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template<typename _BoundFn>
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static std::shared_ptr<_State_base>
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_S_make_deferred_state(_BoundFn&& __fn);
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template<typename _BoundFn>
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static std::shared_ptr<_State_base>
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_S_make_async_state(_BoundFn&& __fn);
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template<typename _Res_ptr,
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typename _Res = typename _Res_ptr::element_type::result_type>
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struct _Task_setter;
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template<typename _Res_ptr, typename _BoundFn>
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static _Task_setter<_Res_ptr>
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_S_task_setter(_Res_ptr& __ptr, _BoundFn&& __call)
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{
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return _Task_setter<_Res_ptr>{ __ptr, std::ref(__call) };
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}
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};
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/// Partial specialization for reference types.
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template<typename _Res>
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struct __future_base::_Result<_Res&> : __future_base::_Result_base
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{
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typedef _Res& result_type;
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_Result() noexcept : _M_value_ptr() { }
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void _M_set(_Res& __res) noexcept { _M_value_ptr = &__res; }
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_Res& _M_get() noexcept { return *_M_value_ptr; }
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private:
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_Res* _M_value_ptr;
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void _M_destroy() { delete this; }
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};
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/// Explicit specialization for void.
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template<>
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struct __future_base::_Result<void> : __future_base::_Result_base
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{
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typedef void result_type;
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private:
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void _M_destroy() { delete this; }
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};
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/// Common implementation for future and shared_future.
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template<typename _Res>
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class __basic_future : public __future_base
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{
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protected:
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typedef shared_ptr<_State_base> __state_type;
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typedef __future_base::_Result<_Res>& __result_type;
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private:
|
|
__state_type _M_state;
|
|
|
|
public:
|
|
// Disable copying.
|
|
__basic_future(const __basic_future&) = delete;
|
|
__basic_future& operator=(const __basic_future&) = delete;
|
|
|
|
bool
|
|
valid() const noexcept { return static_cast<bool>(_M_state); }
|
|
|
|
void
|
|
wait() const
|
|
{
|
|
_State_base::_S_check(_M_state);
|
|
_M_state->wait();
|
|
}
|
|
|
|
template<typename _Rep, typename _Period>
|
|
future_status
|
|
wait_for(const chrono::duration<_Rep, _Period>& __rel) const
|
|
{
|
|
_State_base::_S_check(_M_state);
|
|
return _M_state->wait_for(__rel);
|
|
}
|
|
|
|
template<typename _Clock, typename _Duration>
|
|
future_status
|
|
wait_until(const chrono::time_point<_Clock, _Duration>& __abs) const
|
|
{
|
|
_State_base::_S_check(_M_state);
|
|
return _M_state->wait_until(__abs);
|
|
}
|
|
|
|
protected:
|
|
/// Wait for the state to be ready and rethrow any stored exception
|
|
__result_type
|
|
_M_get_result() const
|
|
{
|
|
_State_base::_S_check(_M_state);
|
|
_Result_base& __res = _M_state->wait();
|
|
if (!(__res._M_error == 0))
|
|
rethrow_exception(__res._M_error);
|
|
return static_cast<__result_type>(__res);
|
|
}
|
|
|
|
void _M_swap(__basic_future& __that) noexcept
|
|
{
|
|
_M_state.swap(__that._M_state);
|
|
}
|
|
|
|
// Construction of a future by promise::get_future()
|
|
explicit
|
|
__basic_future(const __state_type& __state) : _M_state(__state)
|
|
{
|
|
_State_base::_S_check(_M_state);
|
|
_M_state->_M_set_retrieved_flag();
|
|
}
|
|
|
|
// Copy construction from a shared_future
|
|
explicit
|
|
__basic_future(const shared_future<_Res>&) noexcept;
|
|
|
|
// Move construction from a shared_future
|
|
explicit
|
|
__basic_future(shared_future<_Res>&&) noexcept;
|
|
|
|
// Move construction from a future
|
|
explicit
|
|
__basic_future(future<_Res>&&) noexcept;
|
|
|
|
constexpr __basic_future() noexcept : _M_state() { }
|
|
|
|
struct _Reset
|
|
{
|
|
explicit _Reset(__basic_future& __fut) noexcept : _M_fut(__fut) { }
|
|
~_Reset() { _M_fut._M_state.reset(); }
|
|
__basic_future& _M_fut;
|
|
};
|
|
};
|
|
|
|
|
|
/// Primary template for future.
|
|
template<typename _Res>
|
|
class future : public __basic_future<_Res>
|
|
{
|
|
friend class promise<_Res>;
|
|
template<typename> friend class packaged_task;
|
|
template<typename _Fn, typename... _Args>
|
|
friend future<typename result_of<_Fn(_Args...)>::type>
|
|
async(launch, _Fn&&, _Args&&...);
|
|
|
|
typedef __basic_future<_Res> _Base_type;
|
|
typedef typename _Base_type::__state_type __state_type;
|
|
|
|
explicit
|
|
future(const __state_type& __state) : _Base_type(__state) { }
|
|
|
|
public:
|
|
constexpr future() noexcept : _Base_type() { }
|
|
|
|
/// Move constructor
|
|
future(future&& __uf) noexcept : _Base_type(std::move(__uf)) { }
|
|
|
|
// Disable copying
|
|
future(const future&) = delete;
|
|
future& operator=(const future&) = delete;
|
|
|
|
future& operator=(future&& __fut) noexcept
|
|
{
|
|
future(std::move(__fut))._M_swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
/// Retrieving the value
|
|
_Res
|
|
get()
|
|
{
|
|
typename _Base_type::_Reset __reset(*this);
|
|
return std::move(this->_M_get_result()._M_value());
|
|
}
|
|
|
|
shared_future<_Res> share();
|
|
};
|
|
|
|
/// Partial specialization for future<R&>
|
|
template<typename _Res>
|
|
class future<_Res&> : public __basic_future<_Res&>
|
|
{
|
|
friend class promise<_Res&>;
|
|
template<typename> friend class packaged_task;
|
|
template<typename _Fn, typename... _Args>
|
|
friend future<typename result_of<_Fn(_Args...)>::type>
|
|
async(launch, _Fn&&, _Args&&...);
|
|
|
|
typedef __basic_future<_Res&> _Base_type;
|
|
typedef typename _Base_type::__state_type __state_type;
|
|
|
|
explicit
|
|
future(const __state_type& __state) : _Base_type(__state) { }
|
|
|
|
public:
|
|
constexpr future() noexcept : _Base_type() { }
|
|
|
|
/// Move constructor
|
|
future(future&& __uf) noexcept : _Base_type(std::move(__uf)) { }
|
|
|
|
// Disable copying
|
|
future(const future&) = delete;
|
|
future& operator=(const future&) = delete;
|
|
|
|
future& operator=(future&& __fut) noexcept
|
|
{
|
|
future(std::move(__fut))._M_swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
/// Retrieving the value
|
|
_Res&
|
|
get()
|
|
{
|
|
typename _Base_type::_Reset __reset(*this);
|
|
return this->_M_get_result()._M_get();
|
|
}
|
|
|
|
shared_future<_Res&> share();
|
|
};
|
|
|
|
/// Explicit specialization for future<void>
|
|
template<>
|
|
class future<void> : public __basic_future<void>
|
|
{
|
|
friend class promise<void>;
|
|
template<typename> friend class packaged_task;
|
|
template<typename _Fn, typename... _Args>
|
|
friend future<typename result_of<_Fn(_Args...)>::type>
|
|
async(launch, _Fn&&, _Args&&...);
|
|
|
|
typedef __basic_future<void> _Base_type;
|
|
typedef typename _Base_type::__state_type __state_type;
|
|
|
|
explicit
|
|
future(const __state_type& __state) : _Base_type(__state) { }
|
|
|
|
public:
|
|
constexpr future() noexcept : _Base_type() { }
|
|
|
|
/// Move constructor
|
|
future(future&& __uf) noexcept : _Base_type(std::move(__uf)) { }
|
|
|
|
// Disable copying
|
|
future(const future&) = delete;
|
|
future& operator=(const future&) = delete;
|
|
|
|
future& operator=(future&& __fut) noexcept
|
|
{
|
|
future(std::move(__fut))._M_swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
/// Retrieving the value
|
|
void
|
|
get()
|
|
{
|
|
typename _Base_type::_Reset __reset(*this);
|
|
this->_M_get_result();
|
|
}
|
|
|
|
shared_future<void> share();
|
|
};
|
|
|
|
|
|
/// Primary template for shared_future.
|
|
template<typename _Res>
|
|
class shared_future : public __basic_future<_Res>
|
|
{
|
|
typedef __basic_future<_Res> _Base_type;
|
|
|
|
public:
|
|
constexpr shared_future() noexcept : _Base_type() { }
|
|
|
|
/// Copy constructor
|
|
shared_future(const shared_future& __sf) : _Base_type(__sf) { }
|
|
|
|
/// Construct from a future rvalue
|
|
shared_future(future<_Res>&& __uf) noexcept
|
|
: _Base_type(std::move(__uf))
|
|
{ }
|
|
|
|
/// Construct from a shared_future rvalue
|
|
shared_future(shared_future&& __sf) noexcept
|
|
: _Base_type(std::move(__sf))
|
|
{ }
|
|
|
|
shared_future& operator=(const shared_future& __sf)
|
|
{
|
|
shared_future(__sf)._M_swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
shared_future& operator=(shared_future&& __sf) noexcept
|
|
{
|
|
shared_future(std::move(__sf))._M_swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
/// Retrieving the value
|
|
const _Res&
|
|
get() const { return this->_M_get_result()._M_value(); }
|
|
};
|
|
|
|
/// Partial specialization for shared_future<R&>
|
|
template<typename _Res>
|
|
class shared_future<_Res&> : public __basic_future<_Res&>
|
|
{
|
|
typedef __basic_future<_Res&> _Base_type;
|
|
|
|
public:
|
|
constexpr shared_future() noexcept : _Base_type() { }
|
|
|
|
/// Copy constructor
|
|
shared_future(const shared_future& __sf) : _Base_type(__sf) { }
|
|
|
|
/// Construct from a future rvalue
|
|
shared_future(future<_Res&>&& __uf) noexcept
|
|
: _Base_type(std::move(__uf))
|
|
{ }
|
|
|
|
/// Construct from a shared_future rvalue
|
|
shared_future(shared_future&& __sf) noexcept
|
|
: _Base_type(std::move(__sf))
|
|
{ }
|
|
|
|
shared_future& operator=(const shared_future& __sf)
|
|
{
|
|
shared_future(__sf)._M_swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
shared_future& operator=(shared_future&& __sf) noexcept
|
|
{
|
|
shared_future(std::move(__sf))._M_swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
/// Retrieving the value
|
|
_Res&
|
|
get() const { return this->_M_get_result()._M_get(); }
|
|
};
|
|
|
|
/// Explicit specialization for shared_future<void>
|
|
template<>
|
|
class shared_future<void> : public __basic_future<void>
|
|
{
|
|
typedef __basic_future<void> _Base_type;
|
|
|
|
public:
|
|
constexpr shared_future() noexcept : _Base_type() { }
|
|
|
|
/// Copy constructor
|
|
shared_future(const shared_future& __sf) : _Base_type(__sf) { }
|
|
|
|
/// Construct from a future rvalue
|
|
shared_future(future<void>&& __uf) noexcept
|
|
: _Base_type(std::move(__uf))
|
|
{ }
|
|
|
|
/// Construct from a shared_future rvalue
|
|
shared_future(shared_future&& __sf) noexcept
|
|
: _Base_type(std::move(__sf))
|
|
{ }
|
|
|
|
shared_future& operator=(const shared_future& __sf)
|
|
{
|
|
shared_future(__sf)._M_swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
shared_future& operator=(shared_future&& __sf) noexcept
|
|
{
|
|
shared_future(std::move(__sf))._M_swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
// Retrieving the value
|
|
void
|
|
get() const { this->_M_get_result(); }
|
|
};
|
|
|
|
// Now we can define the protected __basic_future constructors.
|
|
template<typename _Res>
|
|
inline __basic_future<_Res>::
|
|
__basic_future(const shared_future<_Res>& __sf) noexcept
|
|
: _M_state(__sf._M_state)
|
|
{ }
|
|
|
|
template<typename _Res>
|
|
inline __basic_future<_Res>::
|
|
__basic_future(shared_future<_Res>&& __sf) noexcept
|
|
: _M_state(std::move(__sf._M_state))
|
|
{ }
|
|
|
|
template<typename _Res>
|
|
inline __basic_future<_Res>::
|
|
__basic_future(future<_Res>&& __uf) noexcept
|
|
: _M_state(std::move(__uf._M_state))
|
|
{ }
|
|
|
|
template<typename _Res>
|
|
inline shared_future<_Res>
|
|
future<_Res>::share()
|
|
{ return shared_future<_Res>(std::move(*this)); }
|
|
|
|
template<typename _Res>
|
|
inline shared_future<_Res&>
|
|
future<_Res&>::share()
|
|
{ return shared_future<_Res&>(std::move(*this)); }
|
|
|
|
inline shared_future<void>
|
|
future<void>::share()
|
|
{ return shared_future<void>(std::move(*this)); }
|
|
|
|
/// Primary template for promise
|
|
template<typename _Res>
|
|
class promise
|
|
{
|
|
typedef __future_base::_State_base _State;
|
|
typedef __future_base::_Result<_Res> _Res_type;
|
|
typedef __future_base::_Ptr<_Res_type> _Ptr_type;
|
|
template<typename, typename> friend class _State::_Setter;
|
|
|
|
shared_ptr<_State> _M_future;
|
|
_Ptr_type _M_storage;
|
|
|
|
public:
|
|
promise()
|
|
: _M_future(std::make_shared<_State>()),
|
|
_M_storage(new _Res_type())
|
|
{ }
|
|
|
|
promise(promise&& __rhs) noexcept
|
|
: _M_future(std::move(__rhs._M_future)),
|
|
_M_storage(std::move(__rhs._M_storage))
|
|
{ }
|
|
|
|
template<typename _Allocator>
|
|
promise(allocator_arg_t, const _Allocator& __a)
|
|
: _M_future(std::allocate_shared<_State>(__a)),
|
|
_M_storage(__future_base::_S_allocate_result<_Res>(__a))
|
|
{ }
|
|
|
|
template<typename _Allocator>
|
|
promise(allocator_arg_t, const _Allocator&, promise&& __rhs)
|
|
: _M_future(std::move(__rhs._M_future)),
|
|
_M_storage(std::move(__rhs._M_storage))
|
|
{ }
|
|
|
|
promise(const promise&) = delete;
|
|
|
|
~promise()
|
|
{
|
|
if (static_cast<bool>(_M_future) && !_M_future.unique())
|
|
_M_future->_M_break_promise(std::move(_M_storage));
|
|
}
|
|
|
|
// Assignment
|
|
promise&
|
|
operator=(promise&& __rhs) noexcept
|
|
{
|
|
promise(std::move(__rhs)).swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
promise& operator=(const promise&) = delete;
|
|
|
|
void
|
|
swap(promise& __rhs) noexcept
|
|
{
|
|
_M_future.swap(__rhs._M_future);
|
|
_M_storage.swap(__rhs._M_storage);
|
|
}
|
|
|
|
// Retrieving the result
|
|
future<_Res>
|
|
get_future()
|
|
{ return future<_Res>(_M_future); }
|
|
|
|
// Setting the result
|
|
void
|
|
set_value(const _Res& __r)
|
|
{
|
|
auto __setter = _State::__setter(this, __r);
|
|
_M_future->_M_set_result(std::move(__setter));
|
|
}
|
|
|
|
void
|
|
set_value(_Res&& __r)
|
|
{
|
|
auto __setter = _State::__setter(this, std::move(__r));
|
|
_M_future->_M_set_result(std::move(__setter));
|
|
}
|
|
|
|
void
|
|
set_exception(exception_ptr __p)
|
|
{
|
|
auto __setter = _State::__setter(__p, this);
|
|
_M_future->_M_set_result(std::move(__setter));
|
|
}
|
|
};
|
|
|
|
template<typename _Res>
|
|
inline void
|
|
swap(promise<_Res>& __x, promise<_Res>& __y) noexcept
|
|
{ __x.swap(__y); }
|
|
|
|
template<typename _Res, typename _Alloc>
|
|
struct uses_allocator<promise<_Res>, _Alloc>
|
|
: public true_type { };
|
|
|
|
|
|
/// Partial specialization for promise<R&>
|
|
template<typename _Res>
|
|
class promise<_Res&>
|
|
{
|
|
typedef __future_base::_State_base _State;
|
|
typedef __future_base::_Result<_Res&> _Res_type;
|
|
typedef __future_base::_Ptr<_Res_type> _Ptr_type;
|
|
template<typename, typename> friend class _State::_Setter;
|
|
|
|
shared_ptr<_State> _M_future;
|
|
_Ptr_type _M_storage;
|
|
|
|
public:
|
|
promise()
|
|
: _M_future(std::make_shared<_State>()),
|
|
_M_storage(new _Res_type())
|
|
{ }
|
|
|
|
promise(promise&& __rhs) noexcept
|
|
: _M_future(std::move(__rhs._M_future)),
|
|
_M_storage(std::move(__rhs._M_storage))
|
|
{ }
|
|
|
|
template<typename _Allocator>
|
|
promise(allocator_arg_t, const _Allocator& __a)
|
|
: _M_future(std::allocate_shared<_State>(__a)),
|
|
_M_storage(__future_base::_S_allocate_result<_Res&>(__a))
|
|
{ }
|
|
|
|
template<typename _Allocator>
|
|
promise(allocator_arg_t, const _Allocator&, promise&& __rhs)
|
|
: _M_future(std::move(__rhs._M_future)),
|
|
_M_storage(std::move(__rhs._M_storage))
|
|
{ }
|
|
|
|
promise(const promise&) = delete;
|
|
|
|
~promise()
|
|
{
|
|
if (static_cast<bool>(_M_future) && !_M_future.unique())
|
|
_M_future->_M_break_promise(std::move(_M_storage));
|
|
}
|
|
|
|
// Assignment
|
|
promise&
|
|
operator=(promise&& __rhs) noexcept
|
|
{
|
|
promise(std::move(__rhs)).swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
promise& operator=(const promise&) = delete;
|
|
|
|
void
|
|
swap(promise& __rhs) noexcept
|
|
{
|
|
_M_future.swap(__rhs._M_future);
|
|
_M_storage.swap(__rhs._M_storage);
|
|
}
|
|
|
|
// Retrieving the result
|
|
future<_Res&>
|
|
get_future()
|
|
{ return future<_Res&>(_M_future); }
|
|
|
|
// Setting the result
|
|
void
|
|
set_value(_Res& __r)
|
|
{
|
|
auto __setter = _State::__setter(this, __r);
|
|
_M_future->_M_set_result(std::move(__setter));
|
|
}
|
|
|
|
void
|
|
set_exception(exception_ptr __p)
|
|
{
|
|
auto __setter = _State::__setter(__p, this);
|
|
_M_future->_M_set_result(std::move(__setter));
|
|
}
|
|
};
|
|
|
|
/// Explicit specialization for promise<void>
|
|
template<>
|
|
class promise<void>
|
|
{
|
|
typedef __future_base::_State_base _State;
|
|
typedef __future_base::_Result<void> _Res_type;
|
|
typedef __future_base::_Ptr<_Res_type> _Ptr_type;
|
|
template<typename, typename> friend class _State::_Setter;
|
|
|
|
shared_ptr<_State> _M_future;
|
|
_Ptr_type _M_storage;
|
|
|
|
public:
|
|
promise()
|
|
: _M_future(std::make_shared<_State>()),
|
|
_M_storage(new _Res_type())
|
|
{ }
|
|
|
|
promise(promise&& __rhs) noexcept
|
|
: _M_future(std::move(__rhs._M_future)),
|
|
_M_storage(std::move(__rhs._M_storage))
|
|
{ }
|
|
|
|
template<typename _Allocator>
|
|
promise(allocator_arg_t, const _Allocator& __a)
|
|
: _M_future(std::allocate_shared<_State>(__a)),
|
|
_M_storage(__future_base::_S_allocate_result<void>(__a))
|
|
{ }
|
|
|
|
// _GLIBCXX_RESOLVE_LIB_DEFECTS
|
|
// 2095. missing constructors needed for uses-allocator construction
|
|
template<typename _Allocator>
|
|
promise(allocator_arg_t, const _Allocator&, promise&& __rhs)
|
|
: _M_future(std::move(__rhs._M_future)),
|
|
_M_storage(std::move(__rhs._M_storage))
|
|
{ }
|
|
|
|
promise(const promise&) = delete;
|
|
|
|
~promise()
|
|
{
|
|
if (static_cast<bool>(_M_future) && !_M_future.unique())
|
|
_M_future->_M_break_promise(std::move(_M_storage));
|
|
}
|
|
|
|
// Assignment
|
|
promise&
|
|
operator=(promise&& __rhs) noexcept
|
|
{
|
|
promise(std::move(__rhs)).swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
promise& operator=(const promise&) = delete;
|
|
|
|
void
|
|
swap(promise& __rhs) noexcept
|
|
{
|
|
_M_future.swap(__rhs._M_future);
|
|
_M_storage.swap(__rhs._M_storage);
|
|
}
|
|
|
|
// Retrieving the result
|
|
future<void>
|
|
get_future()
|
|
{ return future<void>(_M_future); }
|
|
|
|
// Setting the result
|
|
void set_value();
|
|
|
|
void
|
|
set_exception(exception_ptr __p)
|
|
{
|
|
auto __setter = _State::__setter(__p, this);
|
|
_M_future->_M_set_result(std::move(__setter));
|
|
}
|
|
};
|
|
|
|
// set void
|
|
template<>
|
|
struct __future_base::_State_base::_Setter<void, void>
|
|
{
|
|
promise<void>::_Ptr_type operator()()
|
|
{
|
|
_State_base::_S_check(_M_promise->_M_future);
|
|
return std::move(_M_promise->_M_storage);
|
|
}
|
|
|
|
promise<void>* _M_promise;
|
|
};
|
|
|
|
inline __future_base::_State_base::_Setter<void, void>
|
|
__future_base::_State_base::__setter(promise<void>* __prom)
|
|
{
|
|
return _Setter<void, void>{ __prom };
|
|
}
|
|
|
|
inline void
|
|
promise<void>::set_value()
|
|
{
|
|
auto __setter = _State::__setter(this);
|
|
_M_future->_M_set_result(std::move(__setter));
|
|
}
|
|
|
|
|
|
template<typename _Ptr_type, typename _Res>
|
|
struct __future_base::_Task_setter
|
|
{
|
|
_Ptr_type operator()()
|
|
{
|
|
__try
|
|
{
|
|
_M_result->_M_set(_M_fn());
|
|
}
|
|
__catch(...)
|
|
{
|
|
_M_result->_M_error = current_exception();
|
|
}
|
|
return std::move(_M_result);
|
|
}
|
|
_Ptr_type& _M_result;
|
|
std::function<_Res()> _M_fn;
|
|
};
|
|
|
|
template<typename _Ptr_type>
|
|
struct __future_base::_Task_setter<_Ptr_type, void>
|
|
{
|
|
_Ptr_type operator()()
|
|
{
|
|
__try
|
|
{
|
|
_M_fn();
|
|
}
|
|
__catch(...)
|
|
{
|
|
_M_result->_M_error = current_exception();
|
|
}
|
|
return std::move(_M_result);
|
|
}
|
|
_Ptr_type& _M_result;
|
|
std::function<void()> _M_fn;
|
|
};
|
|
|
|
template<typename _Res, typename... _Args>
|
|
struct __future_base::_Task_state_base<_Res(_Args...)>
|
|
: __future_base::_State_base
|
|
{
|
|
typedef _Res _Res_type;
|
|
|
|
template<typename _Alloc>
|
|
_Task_state_base(const _Alloc& __a)
|
|
: _M_result(_S_allocate_result<_Res>(__a))
|
|
{ }
|
|
|
|
virtual void
|
|
_M_run(_Args... __args) = 0;
|
|
|
|
virtual shared_ptr<_Task_state_base>
|
|
_M_reset() = 0;
|
|
|
|
typedef __future_base::_Ptr<_Result<_Res>> _Ptr_type;
|
|
_Ptr_type _M_result;
|
|
};
|
|
|
|
template<typename _Fn, typename _Alloc, typename _Res, typename... _Args>
|
|
struct __future_base::_Task_state<_Fn, _Alloc, _Res(_Args...)> final
|
|
: __future_base::_Task_state_base<_Res(_Args...)>
|
|
{
|
|
_Task_state(_Fn&& __fn, const _Alloc& __a)
|
|
: _Task_state_base<_Res(_Args...)>(__a), _M_impl(std::move(__fn), __a)
|
|
{ }
|
|
|
|
private:
|
|
virtual void
|
|
_M_run(_Args... __args)
|
|
{
|
|
// bound arguments decay so wrap lvalue references
|
|
auto __boundfn = std::__bind_simple(std::ref(_M_impl._M_fn),
|
|
_S_maybe_wrap_ref(std::forward<_Args>(__args))...);
|
|
auto __setter = _S_task_setter(this->_M_result, std::move(__boundfn));
|
|
this->_M_set_result(std::move(__setter));
|
|
}
|
|
|
|
virtual shared_ptr<_Task_state_base<_Res(_Args...)>>
|
|
_M_reset();
|
|
|
|
template<typename _Tp>
|
|
static reference_wrapper<_Tp>
|
|
_S_maybe_wrap_ref(_Tp& __t)
|
|
{ return std::ref(__t); }
|
|
|
|
template<typename _Tp>
|
|
static
|
|
typename enable_if<!is_lvalue_reference<_Tp>::value, _Tp>::type&&
|
|
_S_maybe_wrap_ref(_Tp&& __t)
|
|
{ return std::forward<_Tp>(__t); }
|
|
|
|
struct _Impl : _Alloc
|
|
{
|
|
_Impl(_Fn&& __fn, const _Alloc& __a)
|
|
: _Alloc(__a), _M_fn(std::move(__fn)) { }
|
|
_Fn _M_fn;
|
|
} _M_impl;
|
|
};
|
|
|
|
template<typename _Signature, typename _Fn, typename _Alloc>
|
|
static shared_ptr<__future_base::_Task_state_base<_Signature>>
|
|
__create_task_state(_Fn&& __fn, const _Alloc& __a)
|
|
{
|
|
typedef __future_base::_Task_state<_Fn, _Alloc, _Signature> _State;
|
|
return std::allocate_shared<_State>(__a, std::move(__fn), __a);
|
|
}
|
|
|
|
template<typename _Fn, typename _Alloc, typename _Res, typename... _Args>
|
|
shared_ptr<__future_base::_Task_state_base<_Res(_Args...)>>
|
|
__future_base::_Task_state<_Fn, _Alloc, _Res(_Args...)>::_M_reset()
|
|
{
|
|
return __create_task_state<_Res(_Args...)>(std::move(_M_impl._M_fn),
|
|
static_cast<_Alloc&>(_M_impl));
|
|
}
|
|
|
|
template<typename _Task, typename _Fn, bool
|
|
= is_same<_Task, typename decay<_Fn>::type>::value>
|
|
struct __constrain_pkgdtask
|
|
{ typedef void __type; };
|
|
|
|
template<typename _Task, typename _Fn>
|
|
struct __constrain_pkgdtask<_Task, _Fn, true>
|
|
{ };
|
|
|
|
/// packaged_task
|
|
template<typename _Res, typename... _ArgTypes>
|
|
class packaged_task<_Res(_ArgTypes...)>
|
|
{
|
|
typedef __future_base::_Task_state_base<_Res(_ArgTypes...)> _State_type;
|
|
shared_ptr<_State_type> _M_state;
|
|
|
|
public:
|
|
// Construction and destruction
|
|
packaged_task() noexcept { }
|
|
|
|
// _GLIBCXX_RESOLVE_LIB_DEFECTS
|
|
// 2095. missing constructors needed for uses-allocator construction
|
|
template<typename _Allocator>
|
|
packaged_task(allocator_arg_t, const _Allocator& __a) noexcept
|
|
{ }
|
|
|
|
template<typename _Fn, typename = typename
|
|
__constrain_pkgdtask<packaged_task, _Fn>::__type>
|
|
explicit
|
|
packaged_task(_Fn&& __fn)
|
|
: packaged_task(allocator_arg, std::allocator<int>(), std::move(__fn))
|
|
{ }
|
|
|
|
// _GLIBCXX_RESOLVE_LIB_DEFECTS
|
|
// 2097. packaged_task constructors should be constrained
|
|
template<typename _Fn, typename _Alloc, typename = typename
|
|
__constrain_pkgdtask<packaged_task, _Fn>::__type>
|
|
explicit
|
|
packaged_task(allocator_arg_t, const _Alloc& __a, _Fn&& __fn)
|
|
: _M_state(__create_task_state<_Res(_ArgTypes...)>(
|
|
std::forward<_Fn>(__fn), __a))
|
|
{ }
|
|
|
|
~packaged_task()
|
|
{
|
|
if (static_cast<bool>(_M_state) && !_M_state.unique())
|
|
_M_state->_M_break_promise(std::move(_M_state->_M_result));
|
|
}
|
|
|
|
// No copy
|
|
packaged_task(const packaged_task&) = delete;
|
|
packaged_task& operator=(const packaged_task&) = delete;
|
|
|
|
template<typename _Allocator>
|
|
packaged_task(allocator_arg_t, const _Allocator&,
|
|
const packaged_task&) = delete;
|
|
|
|
// Move support
|
|
packaged_task(packaged_task&& __other) noexcept
|
|
{ this->swap(__other); }
|
|
|
|
template<typename _Allocator>
|
|
packaged_task(allocator_arg_t, const _Allocator&,
|
|
packaged_task&& __other) noexcept
|
|
{ this->swap(__other); }
|
|
|
|
packaged_task& operator=(packaged_task&& __other) noexcept
|
|
{
|
|
packaged_task(std::move(__other)).swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
void
|
|
swap(packaged_task& __other) noexcept
|
|
{ _M_state.swap(__other._M_state); }
|
|
|
|
bool
|
|
valid() const noexcept
|
|
{ return static_cast<bool>(_M_state); }
|
|
|
|
// Result retrieval
|
|
future<_Res>
|
|
get_future()
|
|
{ return future<_Res>(_M_state); }
|
|
|
|
// Execution
|
|
void
|
|
operator()(_ArgTypes... __args)
|
|
{
|
|
__future_base::_State_base::_S_check(_M_state);
|
|
_M_state->_M_run(std::forward<_ArgTypes>(__args)...);
|
|
}
|
|
|
|
void
|
|
reset()
|
|
{
|
|
__future_base::_State_base::_S_check(_M_state);
|
|
packaged_task __tmp;
|
|
__tmp._M_state = _M_state;
|
|
_M_state = _M_state->_M_reset();
|
|
}
|
|
};
|
|
|
|
/// swap
|
|
template<typename _Res, typename... _ArgTypes>
|
|
inline void
|
|
swap(packaged_task<_Res(_ArgTypes...)>& __x,
|
|
packaged_task<_Res(_ArgTypes...)>& __y) noexcept
|
|
{ __x.swap(__y); }
|
|
|
|
template<typename _Res, typename _Alloc>
|
|
struct uses_allocator<packaged_task<_Res>, _Alloc>
|
|
: public true_type { };
|
|
|
|
|
|
template<typename _BoundFn, typename _Res>
|
|
class __future_base::_Deferred_state final
|
|
: public __future_base::_State_base
|
|
{
|
|
public:
|
|
explicit
|
|
_Deferred_state(_BoundFn&& __fn)
|
|
: _M_result(new _Result<_Res>()), _M_fn(std::move(__fn))
|
|
{ }
|
|
|
|
private:
|
|
typedef __future_base::_Ptr<_Result<_Res>> _Ptr_type;
|
|
_Ptr_type _M_result;
|
|
_BoundFn _M_fn;
|
|
|
|
virtual void
|
|
_M_run_deferred()
|
|
{
|
|
// safe to call multiple times so ignore failure
|
|
_M_set_result(_S_task_setter(_M_result, _M_fn), true);
|
|
}
|
|
};
|
|
|
|
class __future_base::_Async_state_common : public __future_base::_State_base
|
|
{
|
|
protected:
|
|
#ifdef _GLIBCXX_ASYNC_ABI_COMPAT
|
|
~_Async_state_common();
|
|
#else
|
|
~_Async_state_common() = default;
|
|
#endif
|
|
|
|
// Allow non-timed waiting functions to block until the thread completes,
|
|
// as if joined.
|
|
virtual void _M_run_deferred() { _M_join(); }
|
|
|
|
void _M_join() { std::call_once(_M_once, &thread::join, ref(_M_thread)); }
|
|
|
|
thread _M_thread;
|
|
once_flag _M_once;
|
|
};
|
|
|
|
template<typename _BoundFn, typename _Res>
|
|
class __future_base::_Async_state_impl final
|
|
: public __future_base::_Async_state_common
|
|
{
|
|
public:
|
|
explicit
|
|
_Async_state_impl(_BoundFn&& __fn)
|
|
: _M_result(new _Result<_Res>()), _M_fn(std::move(__fn))
|
|
{
|
|
_M_thread = std::thread{ [this] {
|
|
_M_set_result(_S_task_setter(_M_result, _M_fn));
|
|
} };
|
|
}
|
|
|
|
~_Async_state_impl() { _M_join(); }
|
|
|
|
private:
|
|
typedef __future_base::_Ptr<_Result<_Res>> _Ptr_type;
|
|
_Ptr_type _M_result;
|
|
_BoundFn _M_fn;
|
|
};
|
|
|
|
template<typename _BoundFn>
|
|
inline std::shared_ptr<__future_base::_State_base>
|
|
__future_base::_S_make_deferred_state(_BoundFn&& __fn)
|
|
{
|
|
typedef typename remove_reference<_BoundFn>::type __fn_type;
|
|
typedef _Deferred_state<__fn_type> __state_type;
|
|
return std::make_shared<__state_type>(std::move(__fn));
|
|
}
|
|
|
|
template<typename _BoundFn>
|
|
inline std::shared_ptr<__future_base::_State_base>
|
|
__future_base::_S_make_async_state(_BoundFn&& __fn)
|
|
{
|
|
typedef typename remove_reference<_BoundFn>::type __fn_type;
|
|
typedef _Async_state_impl<__fn_type> __state_type;
|
|
return std::make_shared<__state_type>(std::move(__fn));
|
|
}
|
|
|
|
|
|
/// async
|
|
template<typename _Fn, typename... _Args>
|
|
future<typename result_of<_Fn(_Args...)>::type>
|
|
async(launch __policy, _Fn&& __fn, _Args&&... __args)
|
|
{
|
|
typedef typename result_of<_Fn(_Args...)>::type result_type;
|
|
std::shared_ptr<__future_base::_State_base> __state;
|
|
if ((__policy & (launch::async|launch::deferred)) == launch::async)
|
|
{
|
|
__state = __future_base::_S_make_async_state(std::__bind_simple(
|
|
std::forward<_Fn>(__fn), std::forward<_Args>(__args)...));
|
|
}
|
|
else
|
|
{
|
|
__state = __future_base::_S_make_deferred_state(std::__bind_simple(
|
|
std::forward<_Fn>(__fn), std::forward<_Args>(__args)...));
|
|
}
|
|
return future<result_type>(__state);
|
|
}
|
|
|
|
/// async, potential overload
|
|
template<typename _Fn, typename... _Args>
|
|
inline future<typename result_of<_Fn(_Args...)>::type>
|
|
async(_Fn&& __fn, _Args&&... __args)
|
|
{
|
|
return async(launch::async|launch::deferred, std::forward<_Fn>(__fn),
|
|
std::forward<_Args>(__args)...);
|
|
}
|
|
|
|
#endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
|
|
// && ATOMIC_INT_LOCK_FREE
|
|
|
|
// @} group futures
|
|
_GLIBCXX_END_NAMESPACE_VERSION
|
|
} // namespace
|
|
|
|
#endif // C++11
|
|
|
|
#endif // _GLIBCXX_FUTURE
|