1368 lines
36 KiB
C++
1368 lines
36 KiB
C++
// <future> -*- C++ -*-
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// Copyright (C) 2009, 2010 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 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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#ifndef __GXX_EXPERIMENTAL_CXX0X__
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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 <memory>
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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 <exception>
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#include <atomic>
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#include <bits/functexcept.h>
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namespace std
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{
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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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broken_promise,
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future_already_retrieved,
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promise_already_satisfied,
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no_state
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};
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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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extern const error_category* const future_category;
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// TODO: requires constexpr
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inline error_code make_error_code(future_errc __errc)
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{ return error_code(static_cast<int>(__errc), *future_category); }
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// TODO: requires constexpr
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inline error_condition make_error_condition(future_errc __errc)
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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() throw();
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virtual const char*
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what() const throw();
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const error_code&
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code() const throw() { 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 _Res>
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class atomic_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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enum class launch { any, async, sync };
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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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typename
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enable_if<!is_same<typename decay<_Fn>::type, launch>::value,
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future<decltype(std::declval<_Fn>()(std::declval<_Args>()...))>
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>::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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&& defined(_GLIBCXX_ATOMIC_BUILTINS_4)
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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() = default;
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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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};
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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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_Result() : _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() { 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() { return static_cast<void*>(&_M_storage); }
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};
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// TODO: use template alias when available
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/*
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template<typename _Res>
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using _Ptr = unique_ptr<_Res, _Result_base::_Deleter>;
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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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struct _Ptr
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{
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typedef unique_ptr<_Res, _Result_base::_Deleter> type;
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};
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// TODO: use when allocator_arg_t available
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/*
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/// Result_alloc.
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template<typename _Res, typename _Alloc>
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struct _Result_alloc : _Result<_Res>
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{
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typedef typename _Alloc::template rebind<_Result_alloc>::other
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__allocator_type;
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explicit
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_Result_alloc(const _Alloc& __a) : _Result<_Res>(), _M_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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__allocator_type __a(_M_alloc);
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__a.destroy(this);
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__a.deallocate(this, 1);
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}
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__allocator_type _M_alloc;
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};
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template<typename _Res, typename _Allocator>
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static typename _Ptr<_Result_alloc<_Res, _Allocator>>::type
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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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typename __result_type::__allocator_type __a2(__a);
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__result_type* __p = __a2.allocate(1);
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__try
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{
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__a2.construct(__p, __a);
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}
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__catch(...)
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{
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__a2.deallocate(__p, 1);
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__throw_exception_again;
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}
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return typename _Ptr<__result_type>::type(__p);
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}
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*/
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/// Shared state between a promise and one or more associated futures.
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class _State
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{
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typedef _Ptr<_Result_base>::type _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() : _M_result(), _M_retrieved(ATOMIC_FLAG_INIT) { }
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_State(const _State&) = delete;
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_State& operator=(const _State&) = delete;
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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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if (!_M_ready())
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_M_cond.wait(__lock, std::bind<bool>(&_State::_M_ready, this));
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return *_M_result;
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}
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template<typename _Rep, typename _Period>
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bool
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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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auto __bound = std::bind<bool>(&_State::_M_ready, this);
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return _M_ready() || _M_cond.wait_for(__lock, __rel, __bound);
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}
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template<typename _Clock, typename _Duration>
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bool
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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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auto __bound = std::bind<bool>(&_State::_M_ready, this);
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return _M_ready() || _M_cond.wait_until(__lock, __abs, __bound);
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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, mem_fn(&_State::_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::_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::_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::_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 bool
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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 { return static_cast<bool>(_M_result); }
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virtual void _M_run_deferred() { }
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};
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template<typename _Res>
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class _Deferred_state;
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template<typename _Res>
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class _Async_state;
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template<typename _Signature>
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class _Task_state;
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template<typename _StateT, typename _Res = typename _StateT::_Res_type>
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struct _Task_setter;
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};
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inline __future_base::_Result_base::~_Result_base() = default;
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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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_Result() : _M_value_ptr() { }
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void _M_set(_Res& __res) { _M_value_ptr = &__res; }
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_Res& _M_get() { 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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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> __state_type;
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typedef __future_base::_Result<_Res>& __result_type;
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private:
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__state_type _M_state;
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public:
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// Disable copying.
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__basic_future(const __basic_future&) = delete;
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__basic_future& operator=(const __basic_future&) = delete;
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bool
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valid() const { return static_cast<bool>(_M_state); }
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void
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wait() const { _M_state->wait(); }
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template<typename _Rep, typename _Period>
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bool
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wait_for(const chrono::duration<_Rep, _Period>& __rel) const
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{ return _M_state->wait_for(__rel); }
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template<typename _Clock, typename _Duration>
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bool
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wait_until(const chrono::time_point<_Clock, _Duration>& __abs) const
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{ return _M_state->wait_until(__abs); }
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protected:
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/// Wait for the state to be ready and rethrow any stored exception
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__result_type
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_M_get_result()
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{
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_Result_base& __res = _M_state->wait();
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if (!(__res._M_error == 0))
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rethrow_exception(__res._M_error);
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return static_cast<__result_type>(__res);
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}
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void _M_swap(__basic_future& __that)
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{
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_M_state.swap(__that._M_state);
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}
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// Construction of a future by promise::get_future()
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explicit
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__basic_future(const __state_type& __state) : _M_state(__state)
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{
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_State::_S_check(_M_state);
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_M_state->_M_set_retrieved_flag();
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}
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// Copy construction from a shared_future
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explicit
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__basic_future(const shared_future<_Res>&);
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// Move construction from a shared_future
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explicit
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__basic_future(shared_future<_Res>&&);
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// Move construction from a future
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explicit
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__basic_future(future<_Res>&&);
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__basic_future() { }
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struct _Reset
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{
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explicit _Reset(__basic_future& __fut) : _M_fut(__fut) { }
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~_Reset() { _M_fut._M_state.reset(); }
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__basic_future& _M_fut;
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};
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};
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/// Primary template for future.
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template<typename _Res>
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class future : public __basic_future<_Res>
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{
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friend class promise<_Res>;
|
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template<typename> friend class packaged_task;
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|
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:
|
|
future() : _Base_type() { }
|
|
|
|
/// Move constructor
|
|
future(future&& __uf) : _Base_type(std::move(__uf)) { }
|
|
|
|
// Disable copying
|
|
future(const future&) = delete;
|
|
future& operator=(const future&) = delete;
|
|
|
|
future& operator=(future&& __fut)
|
|
{
|
|
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());
|
|
}
|
|
};
|
|
|
|
/// 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:
|
|
future() : _Base_type() { }
|
|
|
|
/// Move constructor
|
|
future(future&& __uf) : _Base_type(std::move(__uf)) { }
|
|
|
|
// Disable copying
|
|
future(const future&) = delete;
|
|
future& operator=(const future&) = delete;
|
|
|
|
future& operator=(future&& __fut)
|
|
{
|
|
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();
|
|
}
|
|
};
|
|
|
|
/// 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:
|
|
future() : _Base_type() { }
|
|
|
|
/// Move constructor
|
|
future(future&& __uf) : _Base_type(std::move(__uf)) { }
|
|
|
|
// Disable copying
|
|
future(const future&) = delete;
|
|
future& operator=(const future&) = delete;
|
|
|
|
future& operator=(future&& __fut)
|
|
{
|
|
future(std::move(__fut))._M_swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
/// Retrieving the value
|
|
void
|
|
get()
|
|
{
|
|
typename _Base_type::_Reset __reset(*this);
|
|
this->_M_get_result();
|
|
}
|
|
};
|
|
|
|
|
|
/// Primary template for shared_future.
|
|
template<typename _Res>
|
|
class shared_future : public __basic_future<_Res>
|
|
{
|
|
typedef __basic_future<_Res> _Base_type;
|
|
|
|
public:
|
|
shared_future() : _Base_type() { }
|
|
|
|
/// Copy constructor
|
|
shared_future(const shared_future& __sf) : _Base_type(__sf) { }
|
|
|
|
/// Construct from a future rvalue
|
|
shared_future(future<_Res>&& __uf)
|
|
: _Base_type(std::move(__uf))
|
|
{ }
|
|
|
|
/// Construct from a shared_future rvalue
|
|
shared_future(shared_future&& __sf)
|
|
: _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)
|
|
{
|
|
shared_future(std::move(__sf))._M_swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
/// Retrieving the value
|
|
const _Res&
|
|
get()
|
|
{
|
|
typename _Base_type::__result_type __r = this->_M_get_result();
|
|
_Res& __rs(__r._M_value());
|
|
return __rs;
|
|
}
|
|
};
|
|
|
|
/// Partial specialization for shared_future<R&>
|
|
template<typename _Res>
|
|
class shared_future<_Res&> : public __basic_future<_Res&>
|
|
{
|
|
typedef __basic_future<_Res&> _Base_type;
|
|
|
|
public:
|
|
shared_future() : _Base_type() { }
|
|
|
|
/// Copy constructor
|
|
shared_future(const shared_future& __sf) : _Base_type(__sf) { }
|
|
|
|
/// Construct from a future rvalue
|
|
shared_future(future<_Res&>&& __uf)
|
|
: _Base_type(std::move(__uf))
|
|
{ }
|
|
|
|
/// Construct from a shared_future rvalue
|
|
shared_future(shared_future&& __sf)
|
|
: _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)
|
|
{
|
|
shared_future(std::move(__sf))._M_swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
/// Retrieving the value
|
|
_Res&
|
|
get() { 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:
|
|
shared_future() : _Base_type() { }
|
|
|
|
/// Copy constructor
|
|
shared_future(const shared_future& __sf) : _Base_type(__sf) { }
|
|
|
|
/// Construct from a future rvalue
|
|
shared_future(future<void>&& __uf)
|
|
: _Base_type(std::move(__uf))
|
|
{ }
|
|
|
|
/// Construct from a shared_future rvalue
|
|
shared_future(shared_future&& __sf)
|
|
: _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)
|
|
{
|
|
shared_future(std::move(__sf))._M_swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
// Retrieving the value
|
|
void
|
|
get() { 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)
|
|
: _M_state(__sf._M_state)
|
|
{ }
|
|
|
|
template<typename _Res>
|
|
inline __basic_future<_Res>::
|
|
__basic_future(shared_future<_Res>&& __sf)
|
|
: _M_state(std::move(__sf._M_state))
|
|
{ }
|
|
|
|
template<typename _Res>
|
|
inline __basic_future<_Res>::
|
|
__basic_future(future<_Res>&& __uf)
|
|
: _M_state(std::move(__uf._M_state))
|
|
{ }
|
|
|
|
|
|
/// Primary template for promise
|
|
template<typename _Res>
|
|
class promise
|
|
{
|
|
typedef __future_base::_State _State;
|
|
typedef __future_base::_Result<_Res> _Res_type;
|
|
typedef typename __future_base::_Ptr<_Res_type>::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)
|
|
: _M_future(std::move(__rhs._M_future)),
|
|
_M_storage(std::move(__rhs._M_storage))
|
|
{ }
|
|
|
|
// TODO: needs allocator_arg_t
|
|
/*
|
|
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))
|
|
{ }
|
|
*/
|
|
|
|
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)
|
|
{
|
|
promise(std::move(__rhs)).swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
promise& operator=(const promise&) = delete;
|
|
|
|
void
|
|
swap(promise& __rhs)
|
|
{
|
|
_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)
|
|
{ __x.swap(__y); }
|
|
|
|
/// Partial specialization for promise<R&>
|
|
template<typename _Res>
|
|
class promise<_Res&>
|
|
{
|
|
typedef __future_base::_State _State;
|
|
typedef __future_base::_Result<_Res&> _Res_type;
|
|
typedef typename __future_base::_Ptr<_Res_type>::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)
|
|
: _M_future(std::move(__rhs._M_future)),
|
|
_M_storage(std::move(__rhs._M_storage))
|
|
{ }
|
|
|
|
// TODO: needs allocator_arg_t
|
|
/*
|
|
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))
|
|
{ }
|
|
*/
|
|
|
|
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)
|
|
{
|
|
promise(std::move(__rhs)).swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
promise& operator=(const promise&) = delete;
|
|
|
|
void
|
|
swap(promise& __rhs)
|
|
{
|
|
_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 _State;
|
|
typedef __future_base::_Result<void> _Res_type;
|
|
typedef typename __future_base::_Ptr<_Res_type>::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)
|
|
: _M_future(std::move(__rhs._M_future)),
|
|
_M_storage(std::move(__rhs._M_storage))
|
|
{ }
|
|
|
|
|
|
// TODO: needs allocator_arg_t
|
|
/*
|
|
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))
|
|
{ }
|
|
*/
|
|
|
|
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)
|
|
{
|
|
promise(std::move(__rhs)).swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
promise& operator=(const promise&) = delete;
|
|
|
|
void
|
|
swap(promise& __rhs)
|
|
{
|
|
_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::_Setter<void, void>
|
|
{
|
|
promise<void>::_Ptr_type operator()()
|
|
{
|
|
_State::_S_check(_M_promise->_M_future);
|
|
return std::move(_M_promise->_M_storage);
|
|
}
|
|
|
|
promise<void>* _M_promise;
|
|
};
|
|
|
|
inline __future_base::_State::_Setter<void, void>
|
|
__future_base::_State::__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));
|
|
}
|
|
|
|
// TODO: needs allocators
|
|
/*
|
|
template<typename _Res, class Alloc>
|
|
struct uses_allocator<promise<_Res>, Alloc> : true_type { };
|
|
*/
|
|
|
|
|
|
template<typename _StateT, typename _Res>
|
|
struct __future_base::_Task_setter
|
|
{
|
|
typename _StateT::_Ptr_type operator()()
|
|
{
|
|
__try
|
|
{
|
|
_M_state->_M_result->_M_set(_M_fn());
|
|
}
|
|
__catch(...)
|
|
{
|
|
_M_state->_M_result->_M_error = current_exception();
|
|
}
|
|
return std::move(_M_state->_M_result);
|
|
}
|
|
_StateT* _M_state;
|
|
std::function<_Res()> _M_fn;
|
|
};
|
|
|
|
template<typename _StateT>
|
|
struct __future_base::_Task_setter<_StateT, void>
|
|
{
|
|
typename _StateT::_Ptr_type operator()()
|
|
{
|
|
__try
|
|
{
|
|
_M_fn();
|
|
}
|
|
__catch(...)
|
|
{
|
|
_M_state->_M_result->_M_error = current_exception();
|
|
}
|
|
return std::move(_M_state->_M_result);
|
|
}
|
|
_StateT* _M_state;
|
|
std::function<void()> _M_fn;
|
|
};
|
|
|
|
template<typename _Res, typename... _Args>
|
|
struct __future_base::_Task_state<_Res(_Args...)> : __future_base::_State
|
|
{
|
|
typedef _Res _Res_type;
|
|
|
|
_Task_state(std::function<_Res(_Args...)> __task)
|
|
: _M_result(new _Result<_Res>()), _M_task(std::move(__task))
|
|
{ }
|
|
|
|
// TODO: needs allocator_arg_t
|
|
/*
|
|
template<typename _Func, typename _Alloc>
|
|
_Task_state(_Func&& __task, const _Alloc& __a)
|
|
: _M_result(_S_allocate_result<_Res>(__a))
|
|
, _M_task(allocator_arg, __a, std::move(__task))
|
|
{ }
|
|
*/
|
|
|
|
void
|
|
_M_run(_Args... __args)
|
|
{
|
|
// bound arguments decay so wrap lvalue references
|
|
auto __bound = std::bind<_Res>(_M_task,
|
|
_S_maybe_wrap_ref(std::forward<_Args>(__args))...);
|
|
_Task_setter<_Task_state> __setter{ this, std::move(__bound) };
|
|
_M_set_result(std::move(__setter));
|
|
}
|
|
|
|
template<typename, typename> friend class _Task_setter;
|
|
typedef typename __future_base::_Ptr<_Result<_Res>>::type _Ptr_type;
|
|
_Ptr_type _M_result;
|
|
std::function<_Res(_Args...)> _M_task;
|
|
|
|
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); }
|
|
};
|
|
|
|
/// packaged_task
|
|
template<typename _Res, typename... _ArgTypes>
|
|
class packaged_task<_Res(_ArgTypes...)>
|
|
{
|
|
typedef __future_base::_Task_state<_Res(_ArgTypes...)> _State_type;
|
|
shared_ptr<_State_type> _M_state;
|
|
|
|
public:
|
|
typedef _Res result_type;
|
|
|
|
// Construction and destruction
|
|
packaged_task() { }
|
|
|
|
template<typename _Fn>
|
|
explicit
|
|
packaged_task(const _Fn& __fn)
|
|
: _M_state(std::make_shared<_State_type>(__fn))
|
|
{ }
|
|
|
|
template<typename _Fn>
|
|
explicit
|
|
packaged_task(_Fn&& __fn)
|
|
: _M_state(std::make_shared<_State_type>(std::move(__fn)))
|
|
{ }
|
|
|
|
explicit
|
|
packaged_task(_Res(*__fn)(_ArgTypes...))
|
|
: _M_state(std::make_shared<_State_type>(__fn))
|
|
{ }
|
|
|
|
// TODO: needs allocator_arg_t
|
|
/*
|
|
template<typename _Fn, typename _Allocator>
|
|
explicit
|
|
packaged_task(allocator_arg_t __tag, const _Allocator& __a, _Fn __fn)
|
|
: _M_state(std::allocate_shared<_State_type>(__a, std::move(__fn)))
|
|
{ }
|
|
*/
|
|
|
|
~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(packaged_task&) = delete;
|
|
packaged_task& operator=(packaged_task&) = delete;
|
|
|
|
// Move support
|
|
packaged_task(packaged_task&& __other)
|
|
{ this->swap(__other); }
|
|
|
|
packaged_task& operator=(packaged_task&& __other)
|
|
{
|
|
packaged_task(std::move(__other)).swap(*this);
|
|
return *this;
|
|
}
|
|
|
|
void
|
|
swap(packaged_task& __other)
|
|
{ _M_state.swap(__other._M_state); }
|
|
|
|
explicit operator bool() const { 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::_S_check(_M_state);
|
|
_M_state->_M_run(std::forward<_ArgTypes>(__args)...);
|
|
}
|
|
|
|
void
|
|
reset()
|
|
{
|
|
__future_base::_State::_S_check(_M_state);
|
|
packaged_task(std::move(_M_state->_M_task)).swap(*this);
|
|
}
|
|
};
|
|
|
|
template<typename _Res, typename... _ArgTypes>
|
|
inline void
|
|
swap(packaged_task<_Res(_ArgTypes...)>& __x,
|
|
packaged_task<_Res(_ArgTypes...)>& __y)
|
|
{ __x.swap(__y); }
|
|
|
|
template<typename _Res>
|
|
class __future_base::_Deferred_state : public __future_base::_State
|
|
{
|
|
public:
|
|
typedef _Res _Res_type;
|
|
|
|
explicit
|
|
_Deferred_state(std::function<_Res()>&& __fn)
|
|
: _M_result(new _Result<_Res>()), _M_fn(std::move(__fn))
|
|
{ }
|
|
|
|
private:
|
|
template<typename, typename> friend class _Task_setter;
|
|
typedef typename __future_base::_Ptr<_Result<_Res>>::type _Ptr_type;
|
|
_Ptr_type _M_result;
|
|
std::function<_Res()> _M_fn;
|
|
|
|
virtual void
|
|
_M_run_deferred()
|
|
{
|
|
_Task_setter<_Deferred_state> __setter{ this, _M_fn };
|
|
// safe to call multiple times so ignore failure
|
|
_M_set_result(std::move(__setter), true);
|
|
}
|
|
};
|
|
|
|
template<typename _Res>
|
|
class __future_base::_Async_state : public __future_base::_State
|
|
{
|
|
public:
|
|
typedef _Res _Res_type;
|
|
|
|
explicit
|
|
_Async_state(std::function<_Res()>&& __fn)
|
|
: _M_result(new _Result<_Res>()), _M_fn(std::move(__fn)),
|
|
_M_thread(mem_fn(&_Async_state::_M_do_run), this)
|
|
{ }
|
|
|
|
~_Async_state() { _M_thread.join(); }
|
|
|
|
private:
|
|
void _M_do_run()
|
|
{
|
|
_Task_setter<_Async_state> __setter{ this, std::move(_M_fn) };
|
|
_M_set_result(std::move(__setter));
|
|
}
|
|
|
|
template<typename, typename> friend class _Task_setter;
|
|
typedef typename __future_base::_Ptr<_Result<_Res>>::type _Ptr_type;
|
|
_Ptr_type _M_result;
|
|
std::function<_Res()> _M_fn;
|
|
thread _M_thread;
|
|
};
|
|
|
|
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> __state;
|
|
if (__policy == launch::async)
|
|
{
|
|
typedef typename __future_base::_Async_state<result_type> _State;
|
|
__state = std::make_shared<_State>(std::bind<result_type>(
|
|
std::forward<_Fn>(__fn), std::forward<_Args>(__args)...));
|
|
}
|
|
else
|
|
{
|
|
typedef typename __future_base::_Deferred_state<result_type> _State;
|
|
__state = std::make_shared<_State>(std::bind<result_type>(
|
|
std::forward<_Fn>(__fn), std::forward<_Args>(__args)...));
|
|
}
|
|
return future<result_type>(__state);
|
|
}
|
|
|
|
template<typename _Fn, typename... _Args>
|
|
inline typename
|
|
enable_if<!is_same<typename decay<_Fn>::type, launch>::value,
|
|
future<decltype(std::declval<_Fn>()(std::declval<_Args>()...))>
|
|
>::type
|
|
async(_Fn&& __fn, _Args&&... __args)
|
|
{
|
|
return async(launch::any, std::forward<_Fn>(__fn),
|
|
std::forward<_Args>(__args)...);
|
|
}
|
|
|
|
#endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
|
|
// && _GLIBCXX_ATOMIC_BUILTINS_4
|
|
|
|
// @} group futures
|
|
}
|
|
|
|
#endif // __GXX_EXPERIMENTAL_CXX0X__
|
|
|
|
#endif // _GLIBCXX_FUTURE
|