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Diffstat (limited to 'libstdc++-v3/include/std/future')
| -rw-r--r-- | libstdc++-v3/include/std/future | 1393 |
1 files changed, 1393 insertions, 0 deletions
diff --git a/libstdc++-v3/include/std/future b/libstdc++-v3/include/std/future new file mode 100644 index 000000000..970ce7649 --- /dev/null +++ b/libstdc++-v3/include/std/future @@ -0,0 +1,1393 @@ +// <future> -*- C++ -*- + +// Copyright (C) 2009, 2010, 2011 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. + +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// Under Section 7 of GPL version 3, you are granted additional +// permissions described in the GCC Runtime Library Exception, version +// 3.1, as published by the Free Software Foundation. + +// You should have received a copy of the GNU General Public License and +// a copy of the GCC Runtime Library Exception along with this program; +// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see +// <http://www.gnu.org/licenses/>. + +/** @file include/future + * This is a Standard C++ Library header. + */ + +#ifndef _GLIBCXX_FUTURE +#define _GLIBCXX_FUTURE 1 + +#pragma GCC system_header + +#ifndef __GXX_EXPERIMENTAL_CXX0X__ +# include <bits/c++0x_warning.h> +#else + +#include <functional> +#include <memory> +#include <mutex> +#include <thread> +#include <condition_variable> +#include <system_error> +#include <exception> +#include <atomic> +#include <bits/functexcept.h> + +namespace std _GLIBCXX_VISIBILITY(default) +{ +_GLIBCXX_BEGIN_NAMESPACE_VERSION + + /** + * @defgroup futures Futures + * @ingroup concurrency + * + * Classes for futures support. + * @{ + */ + + /// Error code for futures + enum class future_errc + { + broken_promise, + future_already_retrieved, + promise_already_satisfied, + no_state + }; + + /// Specialization. + template<> + struct is_error_code_enum<future_errc> : public true_type { }; + + /// Points to a statically-allocated object derived from error_category. + const error_category& + future_category(); + + /// Overload for make_error_code. + inline error_code + make_error_code(future_errc __errc) + { return error_code(static_cast<int>(__errc), future_category()); } + + /// Overload for make_error_condition. + inline error_condition + make_error_condition(future_errc __errc) + { return error_condition(static_cast<int>(__errc), future_category()); } + + /** + * @brief Exception type thrown by futures. + * @ingroup exceptions + */ + class future_error : public logic_error + { + error_code _M_code; + + public: + explicit future_error(error_code __ec) + : logic_error("std::future_error"), _M_code(__ec) + { } + + virtual ~future_error() throw(); + + virtual const char* + what() const throw(); + + const error_code& + code() const throw() { return _M_code; } + }; + + // Forward declarations. + template<typename _Res> + class future; + + template<typename _Res> + class shared_future; + + template<typename _Res> + class atomic_future; + + template<typename _Signature> + class packaged_task; + + template<typename _Res> + class promise; + + /// Launch code for futures + enum class launch + { + any, + async, + sync + }; + + /// Status code for futures + enum class future_status + { + ready, + timeout, + deferred + }; + + template<typename _Fn, typename... _Args> + future<typename result_of<_Fn(_Args...)>::type> + async(launch __policy, _Fn&& __fn, _Args&&... __args); + + template<typename _FnCheck, typename _Fn, typename... _Args> + struct __async_sfinae_helper + { + typedef future<typename result_of<_Fn(_Args...)>::type> type; + }; + + template<typename _Fn, typename... _Args> + struct __async_sfinae_helper<launch, _Fn, _Args...> + { }; + + template<typename _Fn, typename... _Args> + typename + __async_sfinae_helper<typename decay<_Fn>::type, _Fn, _Args...>::type + async(_Fn&& __fn, _Args&&... __args); + +#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) \ + && defined(_GLIBCXX_ATOMIC_BUILTINS_4) + + /// Base class and enclosing scope. + struct __future_base + { + /// Base class for results. + struct _Result_base + { + exception_ptr _M_error; + + _Result_base(const _Result_base&) = delete; + _Result_base& operator=(const _Result_base&) = delete; + + // _M_destroy() allows derived classes to control deallocation + virtual void _M_destroy() = 0; + + struct _Deleter + { + void operator()(_Result_base* __fr) const { __fr->_M_destroy(); } + }; + + protected: + _Result_base(); + virtual ~_Result_base(); + }; + + /// Result. + template<typename _Res> + struct _Result : _Result_base + { + private: + typedef alignment_of<_Res> __a_of; + typedef aligned_storage<sizeof(_Res), __a_of::value> __align_storage; + typedef typename __align_storage::type __align_type; + + __align_type _M_storage; + bool _M_initialized; + + public: + _Result() : _M_initialized() { } + + ~_Result() + { + if (_M_initialized) + _M_value().~_Res(); + } + + // Return lvalue, future will add const or rvalue-reference + _Res& + _M_value() { return *static_cast<_Res*>(_M_addr()); } + + void + _M_set(const _Res& __res) + { + ::new (_M_addr()) _Res(__res); + _M_initialized = true; + } + + void + _M_set(_Res&& __res) + { + ::new (_M_addr()) _Res(std::move(__res)); + _M_initialized = true; + } + + private: + void _M_destroy() { delete this; } + + void* _M_addr() { return static_cast<void*>(&_M_storage); } + }; + + // TODO: use template alias when available + /* + template<typename _Res> + using _Ptr = unique_ptr<_Res, _Result_base::_Deleter>; + */ + /// A unique_ptr based on the instantiating type. + template<typename _Res> + struct _Ptr + { + typedef unique_ptr<_Res, _Result_base::_Deleter> type; + }; + + /// Result_alloc. + template<typename _Res, typename _Alloc> + struct _Result_alloc : _Result<_Res>, _Alloc + { + typedef typename _Alloc::template rebind<_Result_alloc>::other + __allocator_type; + + explicit + _Result_alloc(const _Alloc& __a) : _Result<_Res>(), _Alloc(__a) + { } + + private: + void _M_destroy() + { + __allocator_type __a(*this); + __a.destroy(this); + __a.deallocate(this, 1); + } + }; + + template<typename _Res, typename _Allocator> + static typename _Ptr<_Result_alloc<_Res, _Allocator>>::type + _S_allocate_result(const _Allocator& __a) + { + typedef _Result_alloc<_Res, _Allocator> __result_type; + typename __result_type::__allocator_type __a2(__a); + __result_type* __p = __a2.allocate(1); + __try + { + __a2.construct(__p, __a); + } + __catch(...) + { + __a2.deallocate(__p, 1); + __throw_exception_again; + } + return typename _Ptr<__result_type>::type(__p); + } + + + /// Base class for state between a promise and one or more + /// associated futures. + class _State_base + { + typedef _Ptr<_Result_base>::type _Ptr_type; + + _Ptr_type _M_result; + mutex _M_mutex; + condition_variable _M_cond; + atomic_flag _M_retrieved; + once_flag _M_once; + + public: + _State_base() : _M_result(), _M_retrieved(ATOMIC_FLAG_INIT) { } + _State_base(const _State_base&) = delete; + _State_base& operator=(const _State_base&) = delete; + virtual ~_State_base(); + + _Result_base& + wait() + { + _M_run_deferred(); + unique_lock<mutex> __lock(_M_mutex); + if (!_M_ready()) + _M_cond.wait(__lock, std::bind<bool>(&_State_base::_M_ready, this)); + return *_M_result; + } + + template<typename _Rep, typename _Period> + bool + wait_for(const chrono::duration<_Rep, _Period>& __rel) + { + unique_lock<mutex> __lock(_M_mutex); + auto __bound = std::bind<bool>(&_State_base::_M_ready, this); + return _M_ready() || _M_cond.wait_for(__lock, __rel, __bound); + } + + template<typename _Clock, typename _Duration> + bool + wait_until(const chrono::time_point<_Clock, _Duration>& __abs) + { + unique_lock<mutex> __lock(_M_mutex); + auto __bound = std::bind<bool>(&_State_base::_M_ready, this); + return _M_ready() || _M_cond.wait_until(__lock, __abs, __bound); + } + + void + _M_set_result(function<_Ptr_type()> __res, bool __ignore_failure = false) + { + bool __set = __ignore_failure; + // all calls to this function are serialized, + // side-effects of invoking __res only happen once + call_once(_M_once, &_State_base::_M_do_set, this, ref(__res), + ref(__set)); + if (!__set) + __throw_future_error(int(future_errc::promise_already_satisfied)); + } + + void + _M_break_promise(_Ptr_type __res) + { + if (static_cast<bool>(__res)) + { + error_code __ec(make_error_code(future_errc::broken_promise)); + __res->_M_error = copy_exception(future_error(__ec)); + { + lock_guard<mutex> __lock(_M_mutex); + _M_result.swap(__res); + } + _M_cond.notify_all(); + } + } + + // Called when this object is passed to a future. + void + _M_set_retrieved_flag() + { + if (_M_retrieved.test_and_set()) + __throw_future_error(int(future_errc::future_already_retrieved)); + } + + template<typename _Res, typename _Arg> + struct _Setter; + + // set lvalues + template<typename _Res, typename _Arg> + struct _Setter<_Res, _Arg&> + { + // check this is only used by promise<R>::set_value(const R&) + // or promise<R>::set_value(R&) + static_assert(is_same<_Res, _Arg&>::value // promise<R&> + || is_same<const _Res, _Arg>::value, // promise<R> + "Invalid specialisation"); + + typename promise<_Res>::_Ptr_type operator()() + { + _State_base::_S_check(_M_promise->_M_future); + _M_promise->_M_storage->_M_set(_M_arg); + return std::move(_M_promise->_M_storage); + } + promise<_Res>* _M_promise; + _Arg& _M_arg; + }; + + // set rvalues + template<typename _Res> + struct _Setter<_Res, _Res&&> + { + typename promise<_Res>::_Ptr_type operator()() + { + _State_base::_S_check(_M_promise->_M_future); + _M_promise->_M_storage->_M_set(std::move(_M_arg)); + return std::move(_M_promise->_M_storage); + } + promise<_Res>* _M_promise; + _Res& _M_arg; + }; + + struct __exception_ptr_tag { }; + + // set exceptions + template<typename _Res> + struct _Setter<_Res, __exception_ptr_tag> + { + typename promise<_Res>::_Ptr_type operator()() + { + _State_base::_S_check(_M_promise->_M_future); + _M_promise->_M_storage->_M_error = _M_ex; + return std::move(_M_promise->_M_storage); + } + + promise<_Res>* _M_promise; + exception_ptr& _M_ex; + }; + + template<typename _Res, typename _Arg> + static _Setter<_Res, _Arg&&> + __setter(promise<_Res>* __prom, _Arg&& __arg) + { + return _Setter<_Res, _Arg&&>{ __prom, __arg }; + } + + template<typename _Res> + static _Setter<_Res, __exception_ptr_tag> + __setter(exception_ptr& __ex, promise<_Res>* __prom) + { + return _Setter<_Res, __exception_ptr_tag>{ __prom, __ex }; + } + + static _Setter<void, void> + __setter(promise<void>* __prom); + + template<typename _Tp> + static bool + _S_check(const shared_ptr<_Tp>& __p) + { + if (!static_cast<bool>(__p)) + __throw_future_error((int)future_errc::no_state); + } + + private: + void + _M_do_set(function<_Ptr_type()>& __f, bool& __set) + { + _Ptr_type __res = __f(); + { + lock_guard<mutex> __lock(_M_mutex); + _M_result.swap(__res); + } + _M_cond.notify_all(); + __set = true; + } + + bool _M_ready() const { return static_cast<bool>(_M_result); } + + virtual void _M_run_deferred() { } + }; + + template<typename _Res> + class _Deferred_state; + + template<typename _Res> + class _Async_state; + + template<typename _Signature> + class _Task_state; + + template<typename _StateT, typename _Res = typename _StateT::_Res_type> + struct _Task_setter; + }; + + /// Partial specialization for reference types. + template<typename _Res> + struct __future_base::_Result<_Res&> : __future_base::_Result_base + { + _Result() : _M_value_ptr() { } + + void _M_set(_Res& __res) { _M_value_ptr = &__res; } + + _Res& _M_get() { return *_M_value_ptr; } + + private: + _Res* _M_value_ptr; + + void _M_destroy() { delete this; } + }; + + /// Explicit specialization for void. + template<> + struct __future_base::_Result<void> : __future_base::_Result_base + { + private: + void _M_destroy() { delete this; } + }; + + + /// Common implementation for future and shared_future. + template<typename _Res> + class __basic_future : public __future_base + { + protected: + typedef shared_ptr<_State_base> __state_type; + typedef __future_base::_Result<_Res>& __result_type; + + private: + __state_type _M_state; + + public: + // Disable copying. + __basic_future(const __basic_future&) = delete; + __basic_future& operator=(const __basic_future&) = delete; + + bool + valid() const { return static_cast<bool>(_M_state); } + + void + wait() const + { + _State_base::_S_check(_M_state); + _M_state->wait(); + } + + template<typename _Rep, typename _Period> + bool + 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> + bool + 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() + { + _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) + { + _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>&); + + // Move construction from a shared_future + explicit + __basic_future(shared_future<_Res>&&); + + // Move construction from a future + explicit + __basic_future(future<_Res>&&); + + constexpr __basic_future() : _M_state() { } + + struct _Reset + { + explicit _Reset(__basic_future& __fut) : _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() : _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: + constexpr 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: + constexpr 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: + constexpr 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: + constexpr 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: + constexpr 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_base _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)) + { } + + 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); } + + 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 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)) + { } + + 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_base _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)) + { } + + 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_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 _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_base + { + typedef _Res _Res_type; + + _Task_state(std::function<_Res(_Args...)> __task) + : _M_result(new _Result<_Res>()), _M_task(std::move(__task)) + { } + + 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>(std::ref(_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)) + { } + + 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); } + + bool + valid() 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_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(std::move(_M_state->_M_task)).swap(*this); + } + }; + + /// swap + template<typename _Res, typename... _ArgTypes> + inline void + swap(packaged_task<_Res(_ArgTypes...)>& __x, + packaged_task<_Res(_ArgTypes...)>& __y) + { __x.swap(__y); } + + template<typename _Res, typename _Alloc> + struct uses_allocator<packaged_task<_Res>, _Alloc> + : public true_type { }; + + + template<typename _Res> + class __future_base::_Deferred_state : public __future_base::_State_base + { + 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_base + { + 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; + }; + + /// 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) + { + 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); + } + + /// async, potential overload + template<typename _Fn, typename... _Args> + inline typename + __async_sfinae_helper<typename decay<_Fn>::type, _Fn, _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 +_GLIBCXX_END_NAMESPACE_VERSION +} // namespace + +#endif // __GXX_EXPERIMENTAL_CXX0X__ + +#endif // _GLIBCXX_FUTURE |