0,0 → 1,1739 |
// <future> -*- C++ -*- |
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// Copyright (C) 2009-2015 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. |
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// 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 |
|
#if __cplusplus < 201103L |
# include <bits/c++0x_warning.h> |
#else |
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#include <functional> |
#include <mutex> |
#include <thread> |
#include <condition_variable> |
#include <system_error> |
#include <atomic> |
#include <bits/atomic_futex.h> |
#include <bits/functexcept.h> |
#include <bits/unique_ptr.h> |
#include <bits/shared_ptr.h> |
#include <bits/uses_allocator.h> |
#include <bits/allocated_ptr.h> |
#include <ext/aligned_buffer.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 |
{ |
future_already_retrieved = 1, |
promise_already_satisfied, |
no_state, |
broken_promise |
}; |
|
/// 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() noexcept; |
|
/// Overload for make_error_code. |
inline error_code |
make_error_code(future_errc __errc) noexcept |
{ return error_code(static_cast<int>(__errc), future_category()); } |
|
/// Overload for make_error_condition. |
inline error_condition |
make_error_condition(future_errc __errc) noexcept |
{ 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: " + __ec.message()), _M_code(__ec) |
{ } |
|
virtual ~future_error() noexcept; |
|
virtual const char* |
what() const noexcept; |
|
const error_code& |
code() const noexcept { return _M_code; } |
}; |
|
// Forward declarations. |
template<typename _Res> |
class future; |
|
template<typename _Res> |
class shared_future; |
|
template<typename _Signature> |
class packaged_task; |
|
template<typename _Res> |
class promise; |
|
/// Launch code for futures |
enum class launch |
{ |
async = 1, |
deferred = 2 |
}; |
|
constexpr launch operator&(launch __x, launch __y) |
{ |
return static_cast<launch>( |
static_cast<int>(__x) & static_cast<int>(__y)); |
} |
|
constexpr launch operator|(launch __x, launch __y) |
{ |
return static_cast<launch>( |
static_cast<int>(__x) | static_cast<int>(__y)); |
} |
|
constexpr launch operator^(launch __x, launch __y) |
{ |
return static_cast<launch>( |
static_cast<int>(__x) ^ static_cast<int>(__y)); |
} |
|
constexpr launch operator~(launch __x) |
{ return static_cast<launch>(~static_cast<int>(__x)); } |
|
inline launch& operator&=(launch& __x, launch __y) |
{ return __x = __x & __y; } |
|
inline launch& operator|=(launch& __x, launch __y) |
{ return __x = __x | __y; } |
|
inline launch& operator^=(launch& __x, launch __y) |
{ return __x = __x ^ __y; } |
|
/// 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); |
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template<typename _Fn, typename... _Args> |
future<typename result_of<_Fn(_Args...)>::type> |
async(_Fn&& __fn, _Args&&... __args); |
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#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) \ |
&& (ATOMIC_INT_LOCK_FREE > 1) |
|
/// 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(); |
}; |
|
/// A unique_ptr for result objects. |
template<typename _Res> |
using _Ptr = unique_ptr<_Res, _Result_base::_Deleter>; |
|
/// A result object that has storage for an object of type _Res. |
template<typename _Res> |
struct _Result : _Result_base |
{ |
private: |
__gnu_cxx::__aligned_buffer<_Res> _M_storage; |
bool _M_initialized; |
|
public: |
typedef _Res result_type; |
|
_Result() noexcept : _M_initialized() { } |
|
~_Result() |
{ |
if (_M_initialized) |
_M_value().~_Res(); |
} |
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// Return lvalue, future will add const or rvalue-reference |
_Res& |
_M_value() noexcept { return *_M_storage._M_ptr(); } |
|
void |
_M_set(const _Res& __res) |
{ |
::new (_M_storage._M_addr()) _Res(__res); |
_M_initialized = true; |
} |
|
void |
_M_set(_Res&& __res) |
{ |
::new (_M_storage._M_addr()) _Res(std::move(__res)); |
_M_initialized = true; |
} |
|
private: |
void _M_destroy() { delete this; } |
}; |
|
/// A result object that uses an allocator. |
template<typename _Res, typename _Alloc> |
struct _Result_alloc final : _Result<_Res>, _Alloc |
{ |
using __allocator_type = __alloc_rebind<_Alloc, _Result_alloc>; |
|
explicit |
_Result_alloc(const _Alloc& __a) : _Result<_Res>(), _Alloc(__a) |
{ } |
|
private: |
void _M_destroy() |
{ |
__allocator_type __a(*this); |
__allocated_ptr<__allocator_type> __guard_ptr{ __a, this }; |
this->~_Result_alloc(); |
} |
}; |
|
// Create a result object that uses an allocator. |
template<typename _Res, typename _Allocator> |
static _Ptr<_Result_alloc<_Res, _Allocator>> |
_S_allocate_result(const _Allocator& __a) |
{ |
using __result_type = _Result_alloc<_Res, _Allocator>; |
typename __result_type::__allocator_type __a2(__a); |
auto __guard = std::__allocate_guarded(__a2); |
__result_type* __p = ::new((void*)__guard.get()) __result_type{__a}; |
__guard = nullptr; |
return _Ptr<__result_type>(__p); |
} |
|
// Keep it simple for std::allocator. |
template<typename _Res, typename _Tp> |
static _Ptr<_Result<_Res>> |
_S_allocate_result(const std::allocator<_Tp>& __a) |
{ |
return _Ptr<_Result<_Res>>(new _Result<_Res>); |
} |
|
// Base class for various types of shared state created by an |
// asynchronous provider (such as a std::promise) and shared with one |
// or more associated futures. |
class _State_baseV2 |
{ |
typedef _Ptr<_Result_base> _Ptr_type; |
|
enum _Status : unsigned { |
__not_ready, |
__ready |
}; |
|
_Ptr_type _M_result; |
__atomic_futex_unsigned<> _M_status; |
atomic_flag _M_retrieved = ATOMIC_FLAG_INIT; |
once_flag _M_once; |
|
public: |
_State_baseV2() noexcept : _M_result(), _M_status(_Status::__not_ready) |
{ } |
_State_baseV2(const _State_baseV2&) = delete; |
_State_baseV2& operator=(const _State_baseV2&) = delete; |
virtual ~_State_baseV2() = default; |
|
_Result_base& |
wait() |
{ |
// Run any deferred function or join any asynchronous thread: |
_M_complete_async(); |
// Acquire MO makes sure this synchronizes with the thread that made |
// the future ready. |
_M_status._M_load_when_equal(_Status::__ready, memory_order_acquire); |
return *_M_result; |
} |
|
template<typename _Rep, typename _Period> |
future_status |
wait_for(const chrono::duration<_Rep, _Period>& __rel) |
{ |
// First, check if the future has been made ready. Use acquire MO |
// to synchronize with the thread that made it ready. |
if (_M_status._M_load(memory_order_acquire) == _Status::__ready) |
return future_status::ready; |
if (_M_is_deferred_future()) |
return future_status::deferred; |
if (_M_status._M_load_when_equal_for(_Status::__ready, |
memory_order_acquire, __rel)) |
{ |
// _GLIBCXX_RESOLVE_LIB_DEFECTS |
// 2100. timed waiting functions must also join |
// This call is a no-op by default except on an async future, |
// in which case the async thread is joined. It's also not a |
// no-op for a deferred future, but such a future will never |
// reach this point because it returns future_status::deferred |
// instead of waiting for the future to become ready (see |
// above). Async futures synchronize in this call, so we need |
// no further synchronization here. |
_M_complete_async(); |
|
return future_status::ready; |
} |
return future_status::timeout; |
} |
|
template<typename _Clock, typename _Duration> |
future_status |
wait_until(const chrono::time_point<_Clock, _Duration>& __abs) |
{ |
// First, check if the future has been made ready. Use acquire MO |
// to synchronize with the thread that made it ready. |
if (_M_status._M_load(memory_order_acquire) == _Status::__ready) |
return future_status::ready; |
if (_M_is_deferred_future()) |
return future_status::deferred; |
if (_M_status._M_load_when_equal_until(_Status::__ready, |
memory_order_acquire, __abs)) |
{ |
// _GLIBCXX_RESOLVE_LIB_DEFECTS |
// 2100. timed waiting functions must also join |
// See wait_for(...) above. |
_M_complete_async(); |
|
return future_status::ready; |
} |
return future_status::timeout; |
} |
|
// Provide a result to the shared state and make it ready. |
// Calls at most once: _M_result = __res(); |
void |
_M_set_result(function<_Ptr_type()> __res, bool __ignore_failure = false) |
{ |
bool __did_set = false; |
// all calls to this function are serialized, |
// side-effects of invoking __res only happen once |
call_once(_M_once, &_State_baseV2::_M_do_set, this, |
std::__addressof(__res), std::__addressof(__did_set)); |
if (__did_set) |
// Use release MO to synchronize with observers of the ready state. |
_M_status._M_store_notify_all(_Status::__ready, |
memory_order_release); |
else if (!__ignore_failure) |
__throw_future_error(int(future_errc::promise_already_satisfied)); |
} |
|
// Provide a result to the shared state but delay making it ready |
// until the calling thread exits. |
// Calls at most once: _M_result = __res(); |
void |
_M_set_delayed_result(function<_Ptr_type()> __res, |
weak_ptr<_State_baseV2> __self) |
{ |
bool __did_set = false; |
unique_ptr<_Make_ready> __mr{new _Make_ready}; |
// all calls to this function are serialized, |
// side-effects of invoking __res only happen once |
call_once(_M_once, &_State_baseV2::_M_do_set, this, |
std::__addressof(__res), std::__addressof(__did_set)); |
if (!__did_set) |
__throw_future_error(int(future_errc::promise_already_satisfied)); |
__mr->_M_shared_state = std::move(__self); |
__mr->_M_set(); |
__mr.release(); |
} |
|
// Abandon this shared state. |
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 = make_exception_ptr(future_error(__ec)); |
// This function is only called when the last asynchronous result |
// provider is abandoning this shared state, so noone can be |
// trying to make the shared state ready at the same time, and |
// we can access _M_result directly instead of through call_once. |
_M_result.swap(__res); |
// Use release MO to synchronize with observers of the ready state. |
_M_status._M_store_notify_all(_Status::__ready, |
memory_order_release); |
} |
} |
|
// Called when this object is first 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"); |
|
// Used by std::promise to copy construct the result. |
typename promise<_Res>::_Ptr_type operator()() const |
{ |
_State_baseV2::_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&&> |
{ |
// Used by std::promise to move construct the result. |
typename promise<_Res>::_Ptr_type operator()() const |
{ |
_State_baseV2::_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> |
{ |
// Used by std::promise to store an exception as the result. |
typename promise<_Res>::_Ptr_type operator()() const |
{ |
_State_baseV2::_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 }; |
} |
|
template<typename _Tp> |
static void |
_S_check(const shared_ptr<_Tp>& __p) |
{ |
if (!static_cast<bool>(__p)) |
__throw_future_error((int)future_errc::no_state); |
} |
|
private: |
// The function invoked with std::call_once(_M_once, ...). |
void |
_M_do_set(function<_Ptr_type()>* __f, bool* __did_set) |
{ |
_Ptr_type __res = (*__f)(); |
// Notify the caller that we did try to set; if we do not throw an |
// exception, the caller will be aware that it did set (e.g., see |
// _M_set_result). |
*__did_set = true; |
_M_result.swap(__res); // nothrow |
} |
|
// Wait for completion of async function. |
virtual void _M_complete_async() { } |
|
// Return true if state corresponds to a deferred function. |
virtual bool _M_is_deferred_future() const { return false; } |
|
struct _Make_ready final : __at_thread_exit_elt |
{ |
weak_ptr<_State_baseV2> _M_shared_state; |
static void _S_run(void*); |
void _M_set(); |
}; |
}; |
|
#ifdef _GLIBCXX_ASYNC_ABI_COMPAT |
class _State_base; |
class _Async_state_common; |
#else |
using _State_base = _State_baseV2; |
class _Async_state_commonV2; |
#endif |
|
template<typename _BoundFn, typename = typename _BoundFn::result_type> |
class _Deferred_state; |
|
template<typename _BoundFn, typename = typename _BoundFn::result_type> |
class _Async_state_impl; |
|
template<typename _Signature> |
class _Task_state_base; |
|
template<typename _Fn, typename _Alloc, typename _Signature> |
class _Task_state; |
|
template<typename _BoundFn> |
static std::shared_ptr<_State_base> |
_S_make_deferred_state(_BoundFn&& __fn); |
|
template<typename _BoundFn> |
static std::shared_ptr<_State_base> |
_S_make_async_state(_BoundFn&& __fn); |
|
template<typename _Res_ptr, typename _Fn, |
typename _Res = typename _Res_ptr::element_type::result_type> |
struct _Task_setter; |
|
template<typename _Res_ptr, typename _BoundFn> |
static _Task_setter<_Res_ptr, _BoundFn> |
_S_task_setter(_Res_ptr& __ptr, _BoundFn& __call) |
{ |
return { std::__addressof(__ptr), std::__addressof(__call) }; |
} |
}; |
|
/// Partial specialization for reference types. |
template<typename _Res> |
struct __future_base::_Result<_Res&> : __future_base::_Result_base |
{ |
typedef _Res& result_type; |
|
_Result() noexcept : _M_value_ptr() { } |
|
void |
_M_set(_Res& __res) noexcept |
{ _M_value_ptr = std::addressof(__res); } |
|
_Res& _M_get() noexcept { 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 |
{ |
typedef void result_type; |
|
private: |
void _M_destroy() { delete this; } |
}; |
|
#ifndef _GLIBCXX_ASYNC_ABI_COMPAT |
|
// Allow _Setter objects to be stored locally in std::function |
template<typename _Res, typename _Arg> |
struct __is_location_invariant |
<__future_base::_State_base::_Setter<_Res, _Arg>> |
: true_type { }; |
|
// Allow _Task_setter objects to be stored locally in std::function |
template<typename _Res_ptr, typename _Fn, typename _Res> |
struct __is_location_invariant |
<__future_base::_Task_setter<_Res_ptr, _Fn, _Res>> |
: true_type { }; |
|
/// 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 noexcept { return static_cast<bool>(_M_state); } |
|
void |
wait() const |
{ |
_State_base::_S_check(_M_state); |
_M_state->wait(); |
} |
|
template<typename _Rep, typename _Period> |
future_status |
wait_for(const chrono::duration<_Rep, _Period>& __rel) const |
{ |
_State_base::_S_check(_M_state); |
return _M_state->wait_for(__rel); |
} |
|
template<typename _Clock, typename _Duration> |
future_status |
wait_until(const chrono::time_point<_Clock, _Duration>& __abs) const |
{ |
_State_base::_S_check(_M_state); |
return _M_state->wait_until(__abs); |
} |
|
protected: |
/// Wait for the state to be ready and rethrow any stored exception |
__result_type |
_M_get_result() const |
{ |
_State_base::_S_check(_M_state); |
_Result_base& __res = _M_state->wait(); |
if (!(__res._M_error == 0)) |
rethrow_exception(__res._M_error); |
return static_cast<__result_type>(__res); |
} |
|
void _M_swap(__basic_future& __that) noexcept |
{ |
_M_state.swap(__that._M_state); |
} |
|
// Construction of a future by promise::get_future() |
explicit |
__basic_future(const __state_type& __state) : _M_state(__state) |
{ |
_State_base::_S_check(_M_state); |
_M_state->_M_set_retrieved_flag(); |
} |
|
// Copy construction from a shared_future |
explicit |
__basic_future(const shared_future<_Res>&) noexcept; |
|
// Move construction from a shared_future |
explicit |
__basic_future(shared_future<_Res>&&) noexcept; |
|
// Move construction from a future |
explicit |
__basic_future(future<_Res>&&) noexcept; |
|
constexpr __basic_future() noexcept : _M_state() { } |
|
struct _Reset |
{ |
explicit _Reset(__basic_future& __fut) noexcept : _M_fut(__fut) { } |
~_Reset() { _M_fut._M_state.reset(); } |
__basic_future& _M_fut; |
}; |
}; |
|
|
/// Primary template for future. |
template<typename _Res> |
class future : public __basic_future<_Res> |
{ |
friend class promise<_Res>; |
template<typename> friend class packaged_task; |
template<typename _Fn, typename... _Args> |
friend future<typename result_of<_Fn(_Args...)>::type> |
async(launch, _Fn&&, _Args&&...); |
|
typedef __basic_future<_Res> _Base_type; |
typedef typename _Base_type::__state_type __state_type; |
|
explicit |
future(const __state_type& __state) : _Base_type(__state) { } |
|
public: |
constexpr future() noexcept : _Base_type() { } |
|
/// Move constructor |
future(future&& __uf) noexcept : _Base_type(std::move(__uf)) { } |
|
// Disable copying |
future(const future&) = delete; |
future& operator=(const future&) = delete; |
|
future& operator=(future&& __fut) noexcept |
{ |
future(std::move(__fut))._M_swap(*this); |
return *this; |
} |
|
/// Retrieving the value |
_Res |
get() |
{ |
typename _Base_type::_Reset __reset(*this); |
return std::move(this->_M_get_result()._M_value()); |
} |
|
shared_future<_Res> share(); |
}; |
|
/// Partial specialization for future<R&> |
template<typename _Res> |
class future<_Res&> : public __basic_future<_Res&> |
{ |
friend class promise<_Res&>; |
template<typename> friend class packaged_task; |
template<typename _Fn, typename... _Args> |
friend future<typename result_of<_Fn(_Args...)>::type> |
async(launch, _Fn&&, _Args&&...); |
|
typedef __basic_future<_Res&> _Base_type; |
typedef typename _Base_type::__state_type __state_type; |
|
explicit |
future(const __state_type& __state) : _Base_type(__state) { } |
|
public: |
constexpr future() noexcept : _Base_type() { } |
|
/// Move constructor |
future(future&& __uf) noexcept : _Base_type(std::move(__uf)) { } |
|
// Disable copying |
future(const future&) = delete; |
future& operator=(const future&) = delete; |
|
future& operator=(future&& __fut) noexcept |
{ |
future(std::move(__fut))._M_swap(*this); |
return *this; |
} |
|
/// Retrieving the value |
_Res& |
get() |
{ |
typename _Base_type::_Reset __reset(*this); |
return this->_M_get_result()._M_get(); |
} |
|
shared_future<_Res&> share(); |
}; |
|
/// Explicit specialization for future<void> |
template<> |
class future<void> : public __basic_future<void> |
{ |
friend class promise<void>; |
template<typename> friend class packaged_task; |
template<typename _Fn, typename... _Args> |
friend future<typename result_of<_Fn(_Args...)>::type> |
async(launch, _Fn&&, _Args&&...); |
|
typedef __basic_future<void> _Base_type; |
typedef typename _Base_type::__state_type __state_type; |
|
explicit |
future(const __state_type& __state) : _Base_type(__state) { } |
|
public: |
constexpr future() noexcept : _Base_type() { } |
|
/// Move constructor |
future(future&& __uf) noexcept : _Base_type(std::move(__uf)) { } |
|
// Disable copying |
future(const future&) = delete; |
future& operator=(const future&) = delete; |
|
future& operator=(future&& __fut) noexcept |
{ |
future(std::move(__fut))._M_swap(*this); |
return *this; |
} |
|
/// Retrieving the value |
void |
get() |
{ |
typename _Base_type::_Reset __reset(*this); |
this->_M_get_result(); |
} |
|
shared_future<void> share(); |
}; |
|
|
/// Primary template for shared_future. |
template<typename _Res> |
class shared_future : public __basic_future<_Res> |
{ |
typedef __basic_future<_Res> _Base_type; |
|
public: |
constexpr shared_future() noexcept : _Base_type() { } |
|
/// Copy constructor |
shared_future(const shared_future& __sf) : _Base_type(__sf) { } |
|
/// Construct from a future rvalue |
shared_future(future<_Res>&& __uf) noexcept |
: _Base_type(std::move(__uf)) |
{ } |
|
/// Construct from a shared_future rvalue |
shared_future(shared_future&& __sf) noexcept |
: _Base_type(std::move(__sf)) |
{ } |
|
shared_future& operator=(const shared_future& __sf) |
{ |
shared_future(__sf)._M_swap(*this); |
return *this; |
} |
|
shared_future& operator=(shared_future&& __sf) noexcept |
{ |
shared_future(std::move(__sf))._M_swap(*this); |
return *this; |
} |
|
/// Retrieving the value |
const _Res& |
get() const { return this->_M_get_result()._M_value(); } |
}; |
|
/// Partial specialization for shared_future<R&> |
template<typename _Res> |
class shared_future<_Res&> : public __basic_future<_Res&> |
{ |
typedef __basic_future<_Res&> _Base_type; |
|
public: |
constexpr shared_future() noexcept : _Base_type() { } |
|
/// Copy constructor |
shared_future(const shared_future& __sf) : _Base_type(__sf) { } |
|
/// Construct from a future rvalue |
shared_future(future<_Res&>&& __uf) noexcept |
: _Base_type(std::move(__uf)) |
{ } |
|
/// Construct from a shared_future rvalue |
shared_future(shared_future&& __sf) noexcept |
: _Base_type(std::move(__sf)) |
{ } |
|
shared_future& operator=(const shared_future& __sf) |
{ |
shared_future(__sf)._M_swap(*this); |
return *this; |
} |
|
shared_future& operator=(shared_future&& __sf) noexcept |
{ |
shared_future(std::move(__sf))._M_swap(*this); |
return *this; |
} |
|
/// Retrieving the value |
_Res& |
get() const { return this->_M_get_result()._M_get(); } |
}; |
|
/// Explicit specialization for shared_future<void> |
template<> |
class shared_future<void> : public __basic_future<void> |
{ |
typedef __basic_future<void> _Base_type; |
|
public: |
constexpr shared_future() noexcept : _Base_type() { } |
|
/// Copy constructor |
shared_future(const shared_future& __sf) : _Base_type(__sf) { } |
|
/// Construct from a future rvalue |
shared_future(future<void>&& __uf) noexcept |
: _Base_type(std::move(__uf)) |
{ } |
|
/// Construct from a shared_future rvalue |
shared_future(shared_future&& __sf) noexcept |
: _Base_type(std::move(__sf)) |
{ } |
|
shared_future& operator=(const shared_future& __sf) |
{ |
shared_future(__sf)._M_swap(*this); |
return *this; |
} |
|
shared_future& operator=(shared_future&& __sf) noexcept |
{ |
shared_future(std::move(__sf))._M_swap(*this); |
return *this; |
} |
|
// Retrieving the value |
void |
get() const { this->_M_get_result(); } |
}; |
|
// Now we can define the protected __basic_future constructors. |
template<typename _Res> |
inline __basic_future<_Res>:: |
__basic_future(const shared_future<_Res>& __sf) noexcept |
: _M_state(__sf._M_state) |
{ } |
|
template<typename _Res> |
inline __basic_future<_Res>:: |
__basic_future(shared_future<_Res>&& __sf) noexcept |
: _M_state(std::move(__sf._M_state)) |
{ } |
|
template<typename _Res> |
inline __basic_future<_Res>:: |
__basic_future(future<_Res>&& __uf) noexcept |
: _M_state(std::move(__uf._M_state)) |
{ } |
|
template<typename _Res> |
inline shared_future<_Res> |
future<_Res>::share() |
{ return shared_future<_Res>(std::move(*this)); } |
|
template<typename _Res> |
inline shared_future<_Res&> |
future<_Res&>::share() |
{ return shared_future<_Res&>(std::move(*this)); } |
|
inline shared_future<void> |
future<void>::share() |
{ return shared_future<void>(std::move(*this)); } |
|
/// Primary template for promise |
template<typename _Res> |
class promise |
{ |
typedef __future_base::_State_base _State; |
typedef __future_base::_Result<_Res> _Res_type; |
typedef __future_base::_Ptr<_Res_type> _Ptr_type; |
template<typename, typename> friend class _State::_Setter; |
|
shared_ptr<_State> _M_future; |
_Ptr_type _M_storage; |
|
public: |
promise() |
: _M_future(std::make_shared<_State>()), |
_M_storage(new _Res_type()) |
{ } |
|
promise(promise&& __rhs) noexcept |
: _M_future(std::move(__rhs._M_future)), |
_M_storage(std::move(__rhs._M_storage)) |
{ } |
|
template<typename _Allocator> |
promise(allocator_arg_t, const _Allocator& __a) |
: _M_future(std::allocate_shared<_State>(__a)), |
_M_storage(__future_base::_S_allocate_result<_Res>(__a)) |
{ } |
|
template<typename _Allocator> |
promise(allocator_arg_t, const _Allocator&, promise&& __rhs) |
: _M_future(std::move(__rhs._M_future)), |
_M_storage(std::move(__rhs._M_storage)) |
{ } |
|
promise(const promise&) = delete; |
|
~promise() |
{ |
if (static_cast<bool>(_M_future) && !_M_future.unique()) |
_M_future->_M_break_promise(std::move(_M_storage)); |
} |
|
// Assignment |
promise& |
operator=(promise&& __rhs) noexcept |
{ |
promise(std::move(__rhs)).swap(*this); |
return *this; |
} |
|
promise& operator=(const promise&) = delete; |
|
void |
swap(promise& __rhs) noexcept |
{ |
_M_future.swap(__rhs._M_future); |
_M_storage.swap(__rhs._M_storage); |
} |
|
// Retrieving the result |
future<_Res> |
get_future() |
{ return future<_Res>(_M_future); } |
|
// Setting the result |
void |
set_value(const _Res& __r) |
{ _M_future->_M_set_result(_State::__setter(this, __r)); } |
|
void |
set_value(_Res&& __r) |
{ _M_future->_M_set_result(_State::__setter(this, std::move(__r))); } |
|
void |
set_exception(exception_ptr __p) |
{ _M_future->_M_set_result(_State::__setter(__p, this)); } |
|
void |
set_value_at_thread_exit(const _Res& __r) |
{ |
_M_future->_M_set_delayed_result(_State::__setter(this, __r), |
_M_future); |
} |
|
void |
set_value_at_thread_exit(_Res&& __r) |
{ |
_M_future->_M_set_delayed_result( |
_State::__setter(this, std::move(__r)), _M_future); |
} |
|
void |
set_exception_at_thread_exit(exception_ptr __p) |
{ |
_M_future->_M_set_delayed_result(_State::__setter(__p, this), |
_M_future); |
} |
}; |
|
template<typename _Res> |
inline void |
swap(promise<_Res>& __x, promise<_Res>& __y) noexcept |
{ __x.swap(__y); } |
|
template<typename _Res, typename _Alloc> |
struct uses_allocator<promise<_Res>, _Alloc> |
: public true_type { }; |
|
|
/// Partial specialization for promise<R&> |
template<typename _Res> |
class promise<_Res&> |
{ |
typedef __future_base::_State_base _State; |
typedef __future_base::_Result<_Res&> _Res_type; |
typedef __future_base::_Ptr<_Res_type> _Ptr_type; |
template<typename, typename> friend class _State::_Setter; |
|
shared_ptr<_State> _M_future; |
_Ptr_type _M_storage; |
|
public: |
promise() |
: _M_future(std::make_shared<_State>()), |
_M_storage(new _Res_type()) |
{ } |
|
promise(promise&& __rhs) noexcept |
: _M_future(std::move(__rhs._M_future)), |
_M_storage(std::move(__rhs._M_storage)) |
{ } |
|
template<typename _Allocator> |
promise(allocator_arg_t, const _Allocator& __a) |
: _M_future(std::allocate_shared<_State>(__a)), |
_M_storage(__future_base::_S_allocate_result<_Res&>(__a)) |
{ } |
|
template<typename _Allocator> |
promise(allocator_arg_t, const _Allocator&, promise&& __rhs) |
: _M_future(std::move(__rhs._M_future)), |
_M_storage(std::move(__rhs._M_storage)) |
{ } |
|
promise(const promise&) = delete; |
|
~promise() |
{ |
if (static_cast<bool>(_M_future) && !_M_future.unique()) |
_M_future->_M_break_promise(std::move(_M_storage)); |
} |
|
// Assignment |
promise& |
operator=(promise&& __rhs) noexcept |
{ |
promise(std::move(__rhs)).swap(*this); |
return *this; |
} |
|
promise& operator=(const promise&) = delete; |
|
void |
swap(promise& __rhs) noexcept |
{ |
_M_future.swap(__rhs._M_future); |
_M_storage.swap(__rhs._M_storage); |
} |
|
// Retrieving the result |
future<_Res&> |
get_future() |
{ return future<_Res&>(_M_future); } |
|
// Setting the result |
void |
set_value(_Res& __r) |
{ _M_future->_M_set_result(_State::__setter(this, __r)); } |
|
void |
set_exception(exception_ptr __p) |
{ _M_future->_M_set_result(_State::__setter(__p, this)); } |
|
void |
set_value_at_thread_exit(_Res& __r) |
{ |
_M_future->_M_set_delayed_result(_State::__setter(this, __r), |
_M_future); |
} |
|
void |
set_exception_at_thread_exit(exception_ptr __p) |
{ |
_M_future->_M_set_delayed_result(_State::__setter(__p, this), |
_M_future); |
} |
}; |
|
/// Explicit specialization for promise<void> |
template<> |
class promise<void> |
{ |
typedef __future_base::_State_base _State; |
typedef __future_base::_Result<void> _Res_type; |
typedef __future_base::_Ptr<_Res_type> _Ptr_type; |
template<typename, typename> friend class _State::_Setter; |
|
shared_ptr<_State> _M_future; |
_Ptr_type _M_storage; |
|
public: |
promise() |
: _M_future(std::make_shared<_State>()), |
_M_storage(new _Res_type()) |
{ } |
|
promise(promise&& __rhs) noexcept |
: _M_future(std::move(__rhs._M_future)), |
_M_storage(std::move(__rhs._M_storage)) |
{ } |
|
template<typename _Allocator> |
promise(allocator_arg_t, const _Allocator& __a) |
: _M_future(std::allocate_shared<_State>(__a)), |
_M_storage(__future_base::_S_allocate_result<void>(__a)) |
{ } |
|
// _GLIBCXX_RESOLVE_LIB_DEFECTS |
// 2095. missing constructors needed for uses-allocator construction |
template<typename _Allocator> |
promise(allocator_arg_t, const _Allocator&, promise&& __rhs) |
: _M_future(std::move(__rhs._M_future)), |
_M_storage(std::move(__rhs._M_storage)) |
{ } |
|
promise(const promise&) = delete; |
|
~promise() |
{ |
if (static_cast<bool>(_M_future) && !_M_future.unique()) |
_M_future->_M_break_promise(std::move(_M_storage)); |
} |
|
// Assignment |
promise& |
operator=(promise&& __rhs) noexcept |
{ |
promise(std::move(__rhs)).swap(*this); |
return *this; |
} |
|
promise& operator=(const promise&) = delete; |
|
void |
swap(promise& __rhs) noexcept |
{ |
_M_future.swap(__rhs._M_future); |
_M_storage.swap(__rhs._M_storage); |
} |
|
// Retrieving the result |
future<void> |
get_future() |
{ return future<void>(_M_future); } |
|
// Setting the result |
void set_value(); |
|
void |
set_exception(exception_ptr __p) |
{ _M_future->_M_set_result(_State::__setter(__p, this)); } |
|
void |
set_value_at_thread_exit(); |
|
void |
set_exception_at_thread_exit(exception_ptr __p) |
{ |
_M_future->_M_set_delayed_result(_State::__setter(__p, this), |
_M_future); |
} |
}; |
|
// set void |
template<> |
struct __future_base::_State_base::_Setter<void, void> |
{ |
promise<void>::_Ptr_type operator()() const |
{ |
_State_base::_S_check(_M_promise->_M_future); |
return std::move(_M_promise->_M_storage); |
} |
|
promise<void>* _M_promise; |
}; |
|
inline void |
promise<void>::set_value() |
{ _M_future->_M_set_result(_State::_Setter<void, void>{ this }); } |
|
inline void |
promise<void>::set_value_at_thread_exit() |
{ |
_M_future->_M_set_delayed_result(_State::_Setter<void, void>{this}, |
_M_future); |
} |
|
template<typename _Ptr_type, typename _Fn, typename _Res> |
struct __future_base::_Task_setter |
{ |
// Invoke the function and provide the result to the caller. |
_Ptr_type operator()() const |
{ |
__try |
{ |
(*_M_result)->_M_set((*_M_fn)()); |
} |
__catch(const __cxxabiv1::__forced_unwind&) |
{ |
__throw_exception_again; // will cause broken_promise |
} |
__catch(...) |
{ |
(*_M_result)->_M_error = current_exception(); |
} |
return std::move(*_M_result); |
} |
_Ptr_type* _M_result; |
_Fn* _M_fn; |
}; |
|
template<typename _Ptr_type, typename _Fn> |
struct __future_base::_Task_setter<_Ptr_type, _Fn, void> |
{ |
_Ptr_type operator()() const |
{ |
__try |
{ |
(*_M_fn)(); |
} |
__catch(const __cxxabiv1::__forced_unwind&) |
{ |
__throw_exception_again; // will cause broken_promise |
} |
__catch(...) |
{ |
(*_M_result)->_M_error = current_exception(); |
} |
return std::move(*_M_result); |
} |
_Ptr_type* _M_result; |
_Fn* _M_fn; |
}; |
|
// Holds storage for a packaged_task's result. |
template<typename _Res, typename... _Args> |
struct __future_base::_Task_state_base<_Res(_Args...)> |
: __future_base::_State_base |
{ |
typedef _Res _Res_type; |
|
template<typename _Alloc> |
_Task_state_base(const _Alloc& __a) |
: _M_result(_S_allocate_result<_Res>(__a)) |
{ } |
|
// Invoke the stored task and make the state ready. |
virtual void |
_M_run(_Args&&... __args) = 0; |
|
// Invoke the stored task and make the state ready at thread exit. |
virtual void |
_M_run_delayed(_Args&&... __args, weak_ptr<_State_base>) = 0; |
|
virtual shared_ptr<_Task_state_base> |
_M_reset() = 0; |
|
typedef __future_base::_Ptr<_Result<_Res>> _Ptr_type; |
_Ptr_type _M_result; |
}; |
|
// Holds a packaged_task's stored task. |
template<typename _Fn, typename _Alloc, typename _Res, typename... _Args> |
struct __future_base::_Task_state<_Fn, _Alloc, _Res(_Args...)> final |
: __future_base::_Task_state_base<_Res(_Args...)> |
{ |
template<typename _Fn2> |
_Task_state(_Fn2&& __fn, const _Alloc& __a) |
: _Task_state_base<_Res(_Args...)>(__a), |
_M_impl(std::forward<_Fn2>(__fn), __a) |
{ } |
|
private: |
virtual void |
_M_run(_Args&&... __args) |
{ |
// bound arguments decay so wrap lvalue references |
auto __boundfn = std::__bind_simple(std::ref(_M_impl._M_fn), |
_S_maybe_wrap_ref(std::forward<_Args>(__args))...); |
this->_M_set_result(_S_task_setter(this->_M_result, __boundfn)); |
} |
|
virtual void |
_M_run_delayed(_Args&&... __args, weak_ptr<_State_base> __self) |
{ |
// bound arguments decay so wrap lvalue references |
auto __boundfn = std::__bind_simple(std::ref(_M_impl._M_fn), |
_S_maybe_wrap_ref(std::forward<_Args>(__args))...); |
this->_M_set_delayed_result(_S_task_setter(this->_M_result, __boundfn), |
std::move(__self)); |
} |
|
virtual shared_ptr<_Task_state_base<_Res(_Args...)>> |
_M_reset(); |
|
template<typename _Tp> |
static reference_wrapper<_Tp> |
_S_maybe_wrap_ref(_Tp& __t) |
{ return std::ref(__t); } |
|
template<typename _Tp> |
static |
typename enable_if<!is_lvalue_reference<_Tp>::value, _Tp>::type&& |
_S_maybe_wrap_ref(_Tp&& __t) |
{ return std::forward<_Tp>(__t); } |
|
struct _Impl : _Alloc |
{ |
template<typename _Fn2> |
_Impl(_Fn2&& __fn, const _Alloc& __a) |
: _Alloc(__a), _M_fn(std::forward<_Fn2>(__fn)) { } |
_Fn _M_fn; |
} _M_impl; |
}; |
|
template<typename _Signature, typename _Fn, typename _Alloc> |
static shared_ptr<__future_base::_Task_state_base<_Signature>> |
__create_task_state(_Fn&& __fn, const _Alloc& __a) |
{ |
typedef typename decay<_Fn>::type _Fn2; |
typedef __future_base::_Task_state<_Fn2, _Alloc, _Signature> _State; |
return std::allocate_shared<_State>(__a, std::forward<_Fn>(__fn), __a); |
} |
|
template<typename _Fn, typename _Alloc, typename _Res, typename... _Args> |
shared_ptr<__future_base::_Task_state_base<_Res(_Args...)>> |
__future_base::_Task_state<_Fn, _Alloc, _Res(_Args...)>::_M_reset() |
{ |
return __create_task_state<_Res(_Args...)>(std::move(_M_impl._M_fn), |
static_cast<_Alloc&>(_M_impl)); |
} |
|
template<typename _Task, typename _Fn, bool |
= is_same<_Task, typename decay<_Fn>::type>::value> |
struct __constrain_pkgdtask |
{ typedef void __type; }; |
|
template<typename _Task, typename _Fn> |
struct __constrain_pkgdtask<_Task, _Fn, true> |
{ }; |
|
/// packaged_task |
template<typename _Res, typename... _ArgTypes> |
class packaged_task<_Res(_ArgTypes...)> |
{ |
typedef __future_base::_Task_state_base<_Res(_ArgTypes...)> _State_type; |
shared_ptr<_State_type> _M_state; |
|
public: |
// Construction and destruction |
packaged_task() noexcept { } |
|
// _GLIBCXX_RESOLVE_LIB_DEFECTS |
// 2095. missing constructors needed for uses-allocator construction |
template<typename _Allocator> |
packaged_task(allocator_arg_t, const _Allocator& __a) noexcept |
{ } |
|
template<typename _Fn, typename = typename |
__constrain_pkgdtask<packaged_task, _Fn>::__type> |
explicit |
packaged_task(_Fn&& __fn) |
: packaged_task(allocator_arg, std::allocator<int>(), |
std::forward<_Fn>(__fn)) |
{ } |
|
// _GLIBCXX_RESOLVE_LIB_DEFECTS |
// 2097. packaged_task constructors should be constrained |
template<typename _Fn, typename _Alloc, typename = typename |
__constrain_pkgdtask<packaged_task, _Fn>::__type> |
explicit |
packaged_task(allocator_arg_t, const _Alloc& __a, _Fn&& __fn) |
: _M_state(__create_task_state<_Res(_ArgTypes...)>( |
std::forward<_Fn>(__fn), __a)) |
{ } |
|
~packaged_task() |
{ |
if (static_cast<bool>(_M_state) && !_M_state.unique()) |
_M_state->_M_break_promise(std::move(_M_state->_M_result)); |
} |
|
// No copy |
packaged_task(const packaged_task&) = delete; |
packaged_task& operator=(const packaged_task&) = delete; |
|
template<typename _Allocator> |
packaged_task(allocator_arg_t, const _Allocator&, |
const packaged_task&) = delete; |
|
// Move support |
packaged_task(packaged_task&& __other) noexcept |
{ this->swap(__other); } |
|
template<typename _Allocator> |
packaged_task(allocator_arg_t, const _Allocator&, |
packaged_task&& __other) noexcept |
{ this->swap(__other); } |
|
packaged_task& operator=(packaged_task&& __other) noexcept |
{ |
packaged_task(std::move(__other)).swap(*this); |
return *this; |
} |
|
void |
swap(packaged_task& __other) noexcept |
{ _M_state.swap(__other._M_state); } |
|
bool |
valid() const noexcept |
{ return static_cast<bool>(_M_state); } |
|
// Result retrieval |
future<_Res> |
get_future() |
{ return future<_Res>(_M_state); } |
|
// Execution |
void |
operator()(_ArgTypes... __args) |
{ |
__future_base::_State_base::_S_check(_M_state); |
_M_state->_M_run(std::forward<_ArgTypes>(__args)...); |
} |
|
void |
make_ready_at_thread_exit(_ArgTypes... __args) |
{ |
__future_base::_State_base::_S_check(_M_state); |
_M_state->_M_run_delayed(std::forward<_ArgTypes>(__args)..., _M_state); |
} |
|
void |
reset() |
{ |
__future_base::_State_base::_S_check(_M_state); |
packaged_task __tmp; |
__tmp._M_state = _M_state; |
_M_state = _M_state->_M_reset(); |
} |
}; |
|
/// swap |
template<typename _Res, typename... _ArgTypes> |
inline void |
swap(packaged_task<_Res(_ArgTypes...)>& __x, |
packaged_task<_Res(_ArgTypes...)>& __y) noexcept |
{ __x.swap(__y); } |
|
template<typename _Res, typename _Alloc> |
struct uses_allocator<packaged_task<_Res>, _Alloc> |
: public true_type { }; |
|
|
// Shared state created by std::async(). |
// Holds a deferred function and storage for its result. |
template<typename _BoundFn, typename _Res> |
class __future_base::_Deferred_state final |
: public __future_base::_State_base |
{ |
public: |
explicit |
_Deferred_state(_BoundFn&& __fn) |
: _M_result(new _Result<_Res>()), _M_fn(std::move(__fn)) |
{ } |
|
private: |
typedef __future_base::_Ptr<_Result<_Res>> _Ptr_type; |
_Ptr_type _M_result; |
_BoundFn _M_fn; |
|
// Run the deferred function. |
virtual void |
_M_complete_async() |
{ |
// Multiple threads can call a waiting function on the future and |
// reach this point at the same time. The call_once in _M_set_result |
// ensures only the first one run the deferred function, stores the |
// result in _M_result, swaps that with the base _M_result and makes |
// the state ready. Tell _M_set_result to ignore failure so all later |
// calls do nothing. |
_M_set_result(_S_task_setter(_M_result, _M_fn), true); |
} |
|
// Caller should check whether the state is ready first, because this |
// function will return true even after the deferred function has run. |
virtual bool _M_is_deferred_future() const { return true; } |
}; |
|
// Common functionality hoisted out of the _Async_state_impl template. |
class __future_base::_Async_state_commonV2 |
: public __future_base::_State_base |
{ |
protected: |
~_Async_state_commonV2() = default; |
|
// Make waiting functions block until the thread completes, as if joined. |
// |
// This function is used by wait() to satisfy the first requirement below |
// and by wait_for() / wait_until() to satisfy the second. |
// |
// [futures.async]: |
// |
// — a call to a waiting function on an asynchronous return object that |
// shares the shared state created by this async call shall block until |
// the associated thread has completed, as if joined, or else time out. |
// |
// — the associated thread completion synchronizes with the return from |
// the first function that successfully detects the ready status of the |
// shared state or with the return from the last function that releases |
// the shared state, whichever happens first. |
virtual void _M_complete_async() { _M_join(); } |
|
void _M_join() { std::call_once(_M_once, &thread::join, ref(_M_thread)); } |
|
thread _M_thread; |
once_flag _M_once; |
}; |
|
// Shared state created by std::async(). |
// Starts a new thread that runs a function and makes the shared state ready. |
template<typename _BoundFn, typename _Res> |
class __future_base::_Async_state_impl final |
: public __future_base::_Async_state_commonV2 |
{ |
public: |
explicit |
_Async_state_impl(_BoundFn&& __fn) |
: _M_result(new _Result<_Res>()), _M_fn(std::move(__fn)) |
{ |
_M_thread = std::thread{ [this] { |
__try |
{ |
_M_set_result(_S_task_setter(_M_result, _M_fn)); |
} |
__catch (const __cxxabiv1::__forced_unwind&) |
{ |
// make the shared state ready on thread cancellation |
if (static_cast<bool>(_M_result)) |
this->_M_break_promise(std::move(_M_result)); |
__throw_exception_again; |
} |
} }; |
} |
|
// Must not destroy _M_result and _M_fn until the thread finishes. |
// Call join() directly rather than through _M_join() because no other |
// thread can be referring to this state if it is being destroyed. |
~_Async_state_impl() { if (_M_thread.joinable()) _M_thread.join(); } |
|
private: |
typedef __future_base::_Ptr<_Result<_Res>> _Ptr_type; |
_Ptr_type _M_result; |
_BoundFn _M_fn; |
}; |
|
template<typename _BoundFn> |
inline std::shared_ptr<__future_base::_State_base> |
__future_base::_S_make_deferred_state(_BoundFn&& __fn) |
{ |
typedef typename remove_reference<_BoundFn>::type __fn_type; |
typedef _Deferred_state<__fn_type> __state_type; |
return std::make_shared<__state_type>(std::move(__fn)); |
} |
|
template<typename _BoundFn> |
inline std::shared_ptr<__future_base::_State_base> |
__future_base::_S_make_async_state(_BoundFn&& __fn) |
{ |
typedef typename remove_reference<_BoundFn>::type __fn_type; |
typedef _Async_state_impl<__fn_type> __state_type; |
return std::make_shared<__state_type>(std::move(__fn)); |
} |
|
|
/// async |
template<typename _Fn, typename... _Args> |
future<typename result_of<_Fn(_Args...)>::type> |
async(launch __policy, _Fn&& __fn, _Args&&... __args) |
{ |
typedef typename result_of<_Fn(_Args...)>::type result_type; |
std::shared_ptr<__future_base::_State_base> __state; |
if ((__policy & (launch::async|launch::deferred)) == launch::async) |
{ |
__state = __future_base::_S_make_async_state(std::__bind_simple( |
std::forward<_Fn>(__fn), std::forward<_Args>(__args)...)); |
} |
else |
{ |
__state = __future_base::_S_make_deferred_state(std::__bind_simple( |
std::forward<_Fn>(__fn), std::forward<_Args>(__args)...)); |
} |
return future<result_type>(__state); |
} |
|
/// async, potential overload |
template<typename _Fn, typename... _Args> |
inline future<typename result_of<_Fn(_Args...)>::type> |
async(_Fn&& __fn, _Args&&... __args) |
{ |
return async(launch::async|launch::deferred, std::forward<_Fn>(__fn), |
std::forward<_Args>(__args)...); |
} |
|
#endif // _GLIBCXX_ASYNC_ABI_COMPAT |
#endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1 |
// && ATOMIC_INT_LOCK_FREE |
|
// @} group futures |
_GLIBCXX_END_NAMESPACE_VERSION |
} // namespace |
|
#endif // C++11 |
|
#endif // _GLIBCXX_FUTURE |