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Diffstat (limited to 'libstdc++-v3/include/std/future')
| -rw-r--r-- | libstdc++-v3/include/std/future | 925 |
1 files changed, 925 insertions, 0 deletions
diff --git a/libstdc++-v3/include/std/future b/libstdc++-v3/include/std/future new file mode 100644 index 0000000..c485b96 --- /dev/null +++ b/libstdc++-v3/include/std/future @@ -0,0 +1,925 @@ +// <future> -*- C++ -*- + +// Copyright (C) 2009 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 future + * This is a Standard C++ Library header. + */ + +#ifndef _GLIBCXX_FUTURE +#define _GLIBCXX_FUTURE 1 + +#pragma GCC system_header + +#ifndef __GXX_EXPERIMENTAL_CXX0X__ +# include <c++0x_warning.h> +#else + +#include <functional> +#include <memory> +#include <mutex> +#include <condition_variable> +#include <system_error> +#include <exception> +#include <cstdatomic> + +#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) \ + && defined(_GLIBCXX_ATOMIC_BUILTINS_4) + +namespace std +{ + /** + * @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 }; + + // TODO: requires concepts + // concept_map ErrorCodeEnum<future_errc> { } + template<> + struct is_error_code_enum<future_errc> : public true_type { }; + + /// Points to a statically-allocated object derived from error_category. + extern const error_category* const future_category; + + // TODO: requires constexpr + inline error_code make_error_code(future_errc __errc) + { return error_code(static_cast<int>(__errc), *future_category); } + + // TODO: requires constexpr + inline error_condition make_error_condition(future_errc __errc) + { return error_condition(static_cast<int>(__errc), *future_category); } + + /// Exception type thrown by futures. + class future_error : public logic_error + { + public: + explicit future_error(future_errc __ec) + : logic_error("std::future_error"), _M_code(make_error_code(__ec)) + { } + + const error_code& code() const throw() { return _M_code; } + + const char* what() const throw() { return _M_code.message().c_str(); } + + private: + error_code _M_code; + }; + + // Holds the result of a future + struct _Future_result_base + { + _Future_result_base() = default; + _Future_result_base(const _Future_result_base&) = delete; + _Future_result_base& operator=(const _Future_result_base&) = delete; + + exception_ptr _M_error; + + // _M_destroy() allows derived classes to control deallocation, + // which will be needed when allocator support is added to promise. + // See http://gcc.gnu.org/ml/libstdc++/2009-06/msg00032.html + virtual void _M_destroy() = 0; + struct _Deleter + { + void operator()(_Future_result_base* __fr) const { __fr->_M_destroy(); } + }; + + protected: + ~_Future_result_base() = default; + }; + + // TODO: use template alias when available + /* + template<typename _Res> + using _Future_ptr = unique_ptr<_Res, _Future_result_base::_Deleter>; + */ + template<typename _Res> + struct _Future_ptr + { + typedef unique_ptr<_Res, _Future_result_base::_Deleter> type; + }; + + // State shared between a promise and one or more associated futures. + class _Future_state + { + typedef _Future_ptr<_Future_result_base>::type _Future_ptr_type; + + public: + _Future_state() : _M_result(), _M_retrieved(false) { } + + _Future_state(const _Future_state&) = delete; + _Future_state& operator=(const _Future_state&) = delete; + + bool + is_ready() + { return _M_get() != 0; } + + bool + has_exception() + { + _Future_result_base* const __res = _M_get(); + return __res && !(__res->_M_error == 0); + } + + bool + has_value() + { + _Future_result_base* const __res = _M_get(); + return __res && (__res->_M_error == 0); + } + + _Future_result_base& + wait() + { + unique_lock<mutex> __lock(_M_mutex); + if (!_M_ready()) + _M_cond.wait(__lock, std::bind(&_Future_state::_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); + return _M_ready() || _M_cond.wait_for(__lock, __rel, + std::bind(&_Future_state::_M_ready, this)); + } + + template<typename _Clock, typename _Duration> + bool + wait_until(const chrono::time_point<_Clock, _Duration>& __abs) + { + unique_lock<mutex> __lock(_M_mutex); + return _M_ready() || _M_cond.wait_until(__lock, __abs, + std::bind(&_Future_state::_M_ready, this)); + } + + void + _M_set_result(_Future_ptr_type __res) + { + { + lock_guard<mutex> __lock(_M_mutex); + if (_M_ready()) + throw future_error(future_errc::promise_already_satisfied); + _M_result.swap(__res); + } + _M_cond.notify_all(); + } + + void + _M_break_promise(_Future_ptr_type __res) + { + if (static_cast<bool>(__res)) + { + __res->_M_error + = std::copy_exception(future_error(future_errc::broken_promise)); + { + lock_guard<mutex> __lock(_M_mutex); + _M_result.swap(__res); + } + _M_cond.notify_all(); + } + } + + // called when this object is passed to a unique_future + void + _M_set_retrieved_flag() + { + if (_M_retrieved.test_and_set()) + throw future_error(future_errc::future_already_retrieved); + } + + private: + _Future_result_base* + _M_get() + { + lock_guard<mutex> __lock(_M_mutex); + return _M_result.get(); + } + + bool _M_ready() const { return static_cast<bool>(_M_result); } + + _Future_ptr_type _M_result; + mutex _M_mutex; + condition_variable _M_cond; + atomic_flag _M_retrieved; + }; + + // workaround for CWG issue 664 and c++/34022 + template<typename _Result, bool = is_scalar<_Result>::value> + struct _Move_future_result + { + typedef _Result&& __rval_type; + static _Result&& _S_move(_Result& __res) { return std::move(__res); } + }; + + // specialization for scalar types returns rvalue not rvalue-reference + template<typename _Result> + struct _Move_future_result<_Result, true> + { + typedef _Result __rval_type; + static _Result _S_move(_Result __res) { return __res; } + }; + + template<typename _Result> + struct _Future_result : _Future_result_base + { + _Future_result() : _M_initialized() { } + + ~_Future_result() + { + if (_M_initialized) + _M_value().~_Result(); + } + + // return lvalue, future will add const or rvalue-reference + _Result& _M_value() + { return *static_cast<_Result*>(_M_addr()); } + + void + _M_set(const _Result& __res) + { + ::new (_M_addr()) _Result(__res); + _M_initialized = true; + } + + void + _M_set(_Result&& __res) + { + typedef _Move_future_result<_Result> _Mover; + ::new (_M_addr()) _Result(_Mover::_S_move(__res)); + _M_initialized = true; + } + + private: + void _M_destroy() { delete this; } + + void* _M_addr() { return static_cast<void*>(&_M_storage); } + + typename aligned_storage<sizeof(_Result), + alignment_of<_Result>::value>::type _M_storage; + bool _M_initialized; + }; + + template<typename _Result> + struct _Future_result<_Result&> : _Future_result_base + { + _Future_result() : _M_value_ptr() { } + + _Result* _M_value_ptr; + + void _M_destroy() { delete this; } + }; + + template<> + struct _Future_result<void> : _Future_result_base + { + void _M_destroy() { delete this; } + }; + + /// unique_future + template<typename _Result> + class unique_future; + + /// shared_future + template<typename _Result> + class shared_future; + + // common implementation for unique_future and shared_future + template<typename _Result> + class _Future_impl + { + public: + // disable copying + _Future_impl(const _Future_impl&) = delete; + _Future_impl& operator=(const _Future_impl&) = delete; + + // functions to check state and wait for ready + bool is_ready() const { return this->_M_state->is_ready(); } + + bool has_exception() const { return this->_M_state->has_exception(); } + + bool has_value() const { return this->_M_state->has_value(); } + + void wait() const { this->_M_state->wait(); } + + template<typename _Rep, typename _Period> + bool + wait_for(const chrono::duration<_Rep, _Period>& __rel) const + { return this->_M_state->wait_for(__rel); } + + template<typename _Clock, typename _Duration> + bool + wait_until(const chrono::time_point<_Clock, _Duration>& __abs) const + { return this->_M_state->wait_until(__abs); } + + protected: + // wait for the state to be ready and rethrow any stored exception + _Future_result<_Result>& + _M_get_result() + { + _Future_result_base& __res = this->_M_state->wait(); + if (!(__res._M_error == 0)) + rethrow_exception(__res._M_error); + return static_cast<_Future_result<_Result>&>(__res); + } + + typedef shared_ptr<_Future_state> _State_ptr; + + // construction of a unique_future by promise::get_future() + explicit + _Future_impl(const _State_ptr& __state) + : _M_state(__state) + { + if (static_cast<bool>(this->_M_state)) + this->_M_state->_M_set_retrieved_flag(); + else + throw future_error(future_errc::future_already_retrieved); + } + + // copy construction from a shared_future + explicit + _Future_impl(const shared_future<_Result>&); + + // move construction from a unique_future + explicit + _Future_impl(unique_future<_Result>&&); + + _State_ptr _M_state; + }; + + /// promise + template<typename _Result> + class promise; + + // primary template for unique_future + template<typename _Result> + class unique_future : public _Future_impl<_Result> + { + typedef _Move_future_result<_Result> _Mover; + + public: + /// Move constructor + unique_future(unique_future&& __uf) : _Base_type(std::move(__uf)) { } + + // disable copying + unique_future(const unique_future&) = delete; + unique_future& operator=(const unique_future&) = delete; + + // retrieving the value + typename _Mover::__rval_type + get() + { return _Mover::_S_move(this->_M_get_result()._M_value()); } + + private: + typedef _Future_impl<_Result> _Base_type; + typedef typename _Base_type::_State_ptr _State_ptr; + + friend class promise<_Result>; + + explicit + unique_future(const _State_ptr& __state) : _Base_type(__state) { } + }; + + // partial specialization for unique_future<R&> + template<typename _Result> + class unique_future<_Result&> : public _Future_impl<_Result&> + { + public: + /// Move constructor + unique_future(unique_future&& __uf) : _Base_type(std::move(__uf)) { } + + // disable copying + unique_future(const unique_future&) = delete; + unique_future& operator=(const unique_future&) = delete; + + // retrieving the value + _Result& get() { return *this->_M_get_result()._M_value_ptr; } + + private: + typedef _Future_impl<_Result&> _Base_type; + typedef typename _Base_type::_State_ptr _State_ptr; + + friend class promise<_Result&>; + + explicit + unique_future(const _State_ptr& __state) : _Base_type(__state) { } + }; + + // specialization for unique_future<void> + template<> + class unique_future<void> : public _Future_impl<void> + { + public: + /// Move constructor + unique_future(unique_future&& __uf) : _Base_type(std::move(__uf)) { } + + // disable copying + unique_future(const unique_future&) = delete; + unique_future& operator=(const unique_future&) = delete; + + // retrieving the value + void get() { this->_M_get_result(); } + + private: + typedef _Future_impl<void> _Base_type; + typedef _Base_type::_State_ptr _State_ptr; + + friend class promise<void>; + + explicit + unique_future(const _State_ptr& __state) : _Base_type(__state) { } + }; + + // primary template for unique_future + template<typename _Result> + class shared_future : public _Future_impl<_Result> + { + public: + /// Copy constructor + shared_future(const shared_future& __sf) : _Base_type(__sf) { } + + /// Construct from a unique_future rvalue + shared_future(unique_future<_Result>&& __uf) + : _Base_type(std::move(__uf)) + { } + + shared_future& operator=(const shared_future&) = delete; + + // retrieving the value + const _Result& + get() + { return this->_M_get_result()._M_value(); } + + private: + typedef _Future_impl<_Result> _Base_type; + }; + + // partial specialization for shared_future<R&> + template<typename _Result> + class shared_future<_Result&> : public _Future_impl<_Result&> + { + public: + /// Copy constructor + shared_future(const shared_future& __sf) : _Base_type(__sf) { } + + /// Construct from a unique_future rvalue + shared_future(unique_future<_Result&>&& __uf) + : _Base_type(std::move(__uf)) + { } + + shared_future& operator=(const shared_future&) = delete; + + // retrieving the value + _Result& get() { return *this->_M_get_result()._M_value_ptr; } + + private: + typedef _Future_impl<_Result&> _Base_type; + }; + + // specialization for shared_future<void> + template<> + class shared_future<void> : public _Future_impl<void> + { + public: + /// Copy constructor + shared_future(const shared_future& __sf) : _Base_type(__sf) { } + + /// Construct from a unique_future rvalue + shared_future(unique_future<void>&& __uf) + : _Base_type(std::move(__uf)) + { } + + shared_future& operator=(const shared_future&) = delete; + + // retrieving the value + void get() { this->_M_get_result(); } + + private: + typedef _Future_impl<void> _Base_type; + }; + + // now we can define the protected _Future_impl constructors + + template<typename _Result> + _Future_impl<_Result>::_Future_impl(const shared_future<_Result>& __sf) + : _M_state(__sf._M_state) + { } + + template<typename _Result> + _Future_impl<_Result>::_Future_impl(unique_future<_Result>&& __uf) + : _M_state(std::move(__uf._M_state)) + { } + + template<typename> class packaged_task; // undefined + + // primary template for promise + template<typename _Result> + class promise + { + public: + promise() + : _M_future(std::make_shared<_Future_state>()), + _M_storage(new _Future_result<_Result>()) + { } + + promise(promise&& __rhs) + : _M_future(std::move(__rhs._M_future)), + _M_storage(std::move(__rhs._M_storage)) + { } + + // TODO: requires allocator concepts + /* + template<typename _Allocator> + promise(allocator_arg_t, const _Allocator& __a); + + template<typename _Allocator> + promise(allocator_arg_t, const _Allocator&, promise&& __rhs); + */ + + 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 + unique_future<_Result> + get_future() + { return unique_future<_Result>(_M_future); } + + // setting the result + void + set_value(const _Result& __r) + { + if (!_M_satisfied()) + _M_storage->_M_set(__r); + _M_future->_M_set_result(std::move(_M_storage)); + } + + void + set_value(_Result&& __r) + { + if (!_M_satisfied()) + _M_storage->_M_set(_Mover::_S_move(__r)); + _M_future->_M_set_result(std::move(_M_storage)); + } + + void + set_exception(exception_ptr __p) + { + if (!_M_satisfied()) + _M_storage->_M_error = __p; + _M_future->_M_set_result(std::move(_M_storage)); + } + + private: + template<typename> friend class packaged_task; + typedef _Move_future_result<_Result> _Mover; + bool _M_satisfied() { return !static_cast<bool>(_M_storage); } + shared_ptr<_Future_state> _M_future; + typename _Future_ptr<_Future_result<_Result>>::type _M_storage; + }; + + // partial specialization for promise<R&> + template<typename _Result> + class promise<_Result&> + { + public: + promise() + : _M_future(std::make_shared<_Future_state>()), + _M_storage(new _Future_result<_Result&>()) + { } + + promise(promise&& __rhs) + : _M_future(std::move(__rhs._M_future)), + _M_storage(std::move(__rhs._M_storage)) + { } + + // TODO: requires allocator concepts + /* + template<typename _Allocator> + promise(allocator_arg_t, const _Allocator& __a); + + template<typename _Allocator> + promise(allocator_arg_t, const _Allocator&, promise&& __rhs); + */ + + 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 + unique_future<_Result&> + get_future() + { return unique_future<_Result&>(_M_future); } + + // setting the result + void + set_value(_Result& __r) + { + if (!_M_satisfied()) + _M_storage->_M_value_ptr = &__r; + _M_future->_M_set_result(std::move(_M_storage)); + } + + void + set_exception(exception_ptr __p) + { + if (!_M_satisfied()) + _M_storage->_M_error = __p; + _M_future->_M_set_result(std::move(_M_storage)); + } + + private: + template<typename> friend class packaged_task; + bool _M_satisfied() { return !static_cast<bool>(_M_storage); } + shared_ptr<_Future_state> _M_future; + typename _Future_ptr<_Future_result<_Result&>>::type _M_storage; + }; + + // specialization for promise<void> + template<> + class promise<void> + { + public: + promise() + : _M_future(std::make_shared<_Future_state>()), + _M_storage(new _Future_result<void>()) + { } + + promise(promise&& __rhs) + : _M_future(std::move(__rhs._M_future)), + _M_storage(std::move(__rhs._M_storage)) + { } + + // TODO: requires allocator concepts + /* + template<typename _Allocator> + promise(allocator_arg_t, const _Allocator& __a); + + template<typename _Allocator> + promise(allocator_arg_t, const _Allocator&, promise&& __rhs); + */ + + 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 + unique_future<void> + get_future() + { return unique_future<void>(_M_future); } + + // setting the result + void + set_value() + { + _M_future->_M_set_result(std::move(_M_storage)); + } + + void + set_exception(exception_ptr __p) + { + if (!_M_satisfied()) + _M_storage->_M_error = __p; + _M_future->_M_set_result(std::move(_M_storage)); + } + + private: + template<typename> friend class packaged_task; + bool _M_satisfied() { return !static_cast<bool>(_M_storage); } + shared_ptr<_Future_state> _M_future; + _Future_ptr<_Future_result<void>>::type _M_storage; + }; + + // TODO: requires allocator concepts + /* + template<typename _Result, class Alloc> + concept_map UsesAllocator<promise<_Result>, Alloc> + { + typedef Alloc allocator_type; + } + */ + + template<typename _Result, typename... _ArgTypes> + struct _Run_task + { + static void + _S_run(promise<_Result>& __p, function<_Result(_ArgTypes...)>& __f, + _ArgTypes... __args) + { + __p.set_value(__f(std::forward<_ArgTypes>(__args)...)); + } + }; + + // specialization used by packaged_task<void(...)> + template<typename... _ArgTypes> + struct _Run_task<void, _ArgTypes...> + { + static void + _S_run(promise<void>& __p, function<void(_ArgTypes...)>& __f, + _ArgTypes... __args) + { + __f(std::forward<_ArgTypes>(__args)...); + __p.set_value(); + } + }; + + template<typename _Result, typename... _ArgTypes> + class packaged_task<_Result(_ArgTypes...)> + { + public: + typedef _Result result_type; + + // construction and destruction + packaged_task() { } + + template<typename _Fn> + explicit + packaged_task(const _Fn& __fn) : _M_task(__fn) { } + + template<typename _Fn> + explicit + packaged_task(_Fn&& __fn) : _M_task(std::move(__fn)) { } + + explicit + packaged_task(_Result(*__fn)(_ArgTypes...)) : _M_task(__fn) { } + + // TODO: requires allocator concepts + /* + template<typename _Fn, typename _Allocator> + explicit + packaged_task(allocator_arg_t __tag, const _Allocator& __a, _Fn __fn) + : _M_task(__tag, __a, __fn), _M_promise(__tag, __a) + { } + + template<typename _Fn, typename _Allocator> + explicit + packaged_task(allocator_arg_t __tag, const _Allocator& __a, _Fn&& __fn) + : _M_task(__tag, __a, std::move(__fn)), _M_promise(__tag, __a) + { } + */ + + ~packaged_task() = default; + + // 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_task.swap(__other._M_task); + _M_promise.swap(__other._M_promise); + } + + explicit operator bool() const { return static_cast<bool>(_M_task); } + + // result retrieval + unique_future<_Result> + get_future() + { + try + { + return _M_promise.get_future(); + } + catch (const future_error& __e) + { + if (__e.code() == future_errc::future_already_retrieved) + throw std::bad_function_call(); + throw; + } + } + + // execution + void + operator()(_ArgTypes... __args) + { + if (!static_cast<bool>(_M_task) || _M_promise._M_satisfied()) + throw std::bad_function_call(); + try + { + _Run_task<_Result, _ArgTypes...>::_S_run(_M_promise, _M_task, + std::forward<_ArgTypes>(__args)...); + } + catch (...) + { + _M_promise.set_exception(current_exception()); + } + } + + void reset() { promise<_Result>().swap(_M_promise); } + + private: + function<_Result(_ArgTypes...)> _M_task; + promise<_Result> _M_promise; + }; + + // @} group futures +} + +#endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1 + // && _GLIBCXX_ATOMIC_BUILTINS_4 + +#endif // __GXX_EXPERIMENTAL_CXX0X__ + +#endif // _GLIBCXX_FUTURE |