#include <functional>
#include <memory>
#include <mutex>
+#include <thread>
#include <condition_variable>
#include <system_error>
#include <exception>
/// Error code for futures
enum class future_errc
- { broken_promise, future_already_retrieved, promise_already_satisfied };
+ {
+ broken_promise,
+ future_already_retrieved,
+ promise_already_satisfied,
+ no_state
+ };
- // TODO: requires concepts
- // concept_map ErrorCodeEnum<future_errc> { }
template<>
struct is_error_code_enum<future_errc> : public true_type { };
error_code _M_code;
public:
- explicit future_error(future_errc __ec)
- : logic_error("std::future_error"), _M_code(make_error_code(__ec))
+ explicit future_error(error_code __ec)
+ : logic_error("std::future_error"), _M_code(__ec)
{ }
virtual ~future_error() throw();
// Forward declarations.
template<typename _Res>
- class unique_future;
+ class future;
template<typename _Res>
class shared_future;
- template<typename>
+ template<typename _Res>
+ class atomic_future;
+
+ template<typename _Signature>
class packaged_task;
template<typename _Res>
class promise;
+ enum class launch { any, async, sync };
+
+ template<typename _Fn, typename... _Args>
+ future<typename _Fn::result_type>
+ async(launch __policy, _Fn&& __fn, _Args&&... __args);
+
+ template<typename _Fn, typename... _Args>
+ future<typename _Fn::result_type>
+ async(_Fn&& __fn, _Args&&... __args);
+
#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) \
&& defined(_GLIBCXX_ATOMIC_BUILTINS_4)
_Result_base(const _Result_base&) = delete;
_Result_base& operator=(const _Result_base&) = delete;
- // _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
+ // _M_destroy() allows derived classes to control deallocation
virtual void _M_destroy() = 0;
struct _Deleter
void* _M_addr() { return static_cast<void*>(&_M_storage); }
};
-
// TODO: use template alias when available
/*
template<typename _Res>
typedef unique_ptr<_Res, _Result_base::_Deleter> type;
};
+ // TODO: use when allocator_arg_t available
+ /*
+ /// Result_alloc.
+ template<typename _Res, typename _Alloc>
+ struct _Result_alloc : _Result<_Res>
+ {
+ typedef typename _Alloc::template rebind<_Result_alloc>::other
+ __allocator_type;
+
+ explicit
+ _Result_alloc(const _Alloc& __a) : _Result<_Res>(), _M_alloc(__a)
+ { }
+
+ private:
+ void _M_destroy()
+ {
+ __allocator_type __a(_M_alloc);
+ __a.destroy(this);
+ __a.deallocate(this, 1);
+ }
+
+ __allocator_type _M_alloc;
+ };
+
+ 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);
+ }
+ */
+
/// Shared state between a promise and one or more associated futures.
class _State
mutex _M_mutex;
condition_variable _M_cond;
atomic_flag _M_retrieved;
+ once_flag _M_once;
public:
_State() : _M_result(), _M_retrieved(ATOMIC_FLAG_INIT) { }
_State(const _State&) = delete;
_State& operator=(const _State&) = delete;
- bool
- is_ready()
- { return _M_get() != 0; }
-
- bool
- has_exception()
- {
- _Result_base* const __res = _M_get();
- return __res && !(__res->_M_error == 0);
- }
-
- bool
- has_value()
- {
- _Result_base* const __res = _M_get();
- return __res && (__res->_M_error == 0);
- }
-
_Result_base&
wait()
{
+ _M_run_deferred();
unique_lock<mutex> __lock(_M_mutex);
if (!_M_ready())
- _M_cond.wait(__lock, std::bind(&_State::_M_ready, this));
+ _M_cond.wait(__lock, std::bind<bool>(&_State::_M_ready, this));
return *_M_result;
}
wait_for(const chrono::duration<_Rep, _Period>& __rel)
{
unique_lock<mutex> __lock(_M_mutex);
- auto __bound = std::bind(&_State::_M_ready, this);
+ auto __bound = std::bind<bool>(&_State::_M_ready, this);
return _M_ready() || _M_cond.wait_for(__lock, __rel, __bound);
}
wait_until(const chrono::time_point<_Clock, _Duration>& __abs)
{
unique_lock<mutex> __lock(_M_mutex);
- auto __bound = std::bind(&_State::_M_ready, this);
+ auto __bound = std::bind<bool>(&_State::_M_ready, this);
return _M_ready() || _M_cond.wait_until(__lock, __abs, __bound);
}
void
- _M_set_result(_Ptr_type __res)
+ _M_set_result(function<_Ptr_type()> __res, bool __ignore_failure = false)
{
- {
- lock_guard<mutex> __lock(_M_mutex);
- if (_M_ready())
- __throw_future_error(int(future_errc::promise_already_satisfied));
- _M_result.swap(__res);
- }
- _M_cond.notify_all();
+ bool __set = __ignore_failure;
+ // all calls to this function are serialized,
+ // side-effects of invoking __res only happen once
+ call_once(_M_once, mem_fn(&_State::_M_do_set), this, ref(__res),
+ ref(__set));
+ if (!__set)
+ __throw_future_error(int(future_errc::promise_already_satisfied));
}
void
{
if (static_cast<bool>(__res))
{
- future_errc __ec(future_errc::broken_promise); // XXX
+ error_code __ec(make_error_code(future_errc::broken_promise));
__res->_M_error = copy_exception(future_error(__ec));
{
lock_guard<mutex> __lock(_M_mutex);
}
}
- // Called when this object is passed to a unique_future.
+ // Called when this object is passed to a future.
void
_M_set_retrieved_flag()
{
__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::_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::_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::_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:
- _Result_base*
- _M_get()
+ void
+ _M_do_set(function<_Ptr_type()>& __f, bool& __set)
{
- lock_guard<mutex> __lock(_M_mutex);
- return _M_result.get();
+ _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;
};
inline __future_base::_Result_base::~_Result_base() = default;
{
_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;
- private:
void _M_destroy() { delete this; }
};
};
- /// Common implementation for unique_future and shared_future.
+ /// Common implementation for future and shared_future.
template<typename _Res>
class __basic_future : public __future_base
{
__basic_future(const __basic_future&) = delete;
__basic_future& operator=(const __basic_future&) = 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(); }
+ valid() const { return static_cast<bool>(_M_state); }
void
- wait() const { this->_M_state->wait(); }
+ wait() const { _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); }
+ { return _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); }
+ { return _M_state->wait_until(__abs); }
protected:
/// Wait for the state to be ready and rethrow any stored exception
__result_type
_M_get_result()
{
- _Result_base& __res = this->_M_state->wait();
+ _Result_base& __res = _M_state->wait();
if (!(__res._M_error == 0))
rethrow_exception(__res._M_error);
return static_cast<__result_type>(__res);
}
- // Construction of a unique_future by promise::get_future()
+ 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)
{
- if (static_cast<bool>(this->_M_state))
- this->_M_state->_M_set_retrieved_flag();
- else
- __throw_future_error(int(future_errc::future_already_retrieved));
+ _State::_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 unique_future
+ // Move construction from a shared_future
explicit
- __basic_future(unique_future<_Res>&&);
+ __basic_future(shared_future<_Res>&&);
+
+ // Move construction from a future
+ explicit
+ __basic_future(future<_Res>&&);
+
+ __basic_future() { }
+
+ struct _Reset
+ {
+ explicit _Reset(__basic_future& __fut) : _M_fut(__fut) { }
+ ~_Reset() { _M_fut._M_state.reset(); }
+ __basic_future& _M_fut;
+ };
};
- /// Primary template for unique_future.
+ /// Primary template for future.
template<typename _Res>
- class unique_future : public __basic_future<_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 _Fn::result_type>
+ async(launch, _Fn&&, _Args&&...);
typedef __basic_future<_Res> _Base_type;
typedef typename _Base_type::__state_type __state_type;
explicit
- unique_future(const __state_type& __state) : _Base_type(__state) { }
+ future(const __state_type& __state) : _Base_type(__state) { }
public:
+ future() : _Base_type() { }
+
/// Move constructor
- unique_future(unique_future&& __uf) : _Base_type(std::move(__uf)) { }
+ future(future&& __uf) : _Base_type(std::move(__uf)) { }
// Disable copying
- unique_future(const unique_future&) = delete;
- unique_future& operator=(const unique_future&) = delete;
+ 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&&
+ _Res
get()
- { return std::move(this->_M_get_result()._M_value()); }
+ {
+ typename _Base_type::_Reset __reset(*this);
+ return std::move(this->_M_get_result()._M_value());
+ }
};
- /// Partial specialization for unique_future<R&>
+ /// Partial specialization for future<R&>
template<typename _Res>
- class unique_future<_Res&> : public __basic_future<_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 _Fn::result_type>
+ async(launch, _Fn&&, _Args&&...);
typedef __basic_future<_Res&> _Base_type;
typedef typename _Base_type::__state_type __state_type;
explicit
- unique_future(const __state_type& __state) : _Base_type(__state) { }
+ future(const __state_type& __state) : _Base_type(__state) { }
public:
+ future() : _Base_type() { }
+
/// Move constructor
- unique_future(unique_future&& __uf) : _Base_type(std::move(__uf)) { }
+ future(future&& __uf) : _Base_type(std::move(__uf)) { }
// Disable copying
- unique_future(const unique_future&) = delete;
- unique_future& operator=(const unique_future&) = delete;
+ 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() { return *this->_M_get_result()._M_value_ptr; }
+ get()
+ {
+ typename _Base_type::_Reset __reset(*this);
+ return this->_M_get_result()._M_get();
+ }
};
- /// Explicit specialization for unique_future<void>
+ /// Explicit specialization for future<void>
template<>
- class unique_future<void> : public __basic_future<void>
+ 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 _Fn::result_type>
+ async(launch, _Fn&&, _Args&&...);
typedef __basic_future<void> _Base_type;
typedef typename _Base_type::__state_type __state_type;
explicit
- unique_future(const __state_type& __state) : _Base_type(__state) { }
+ future(const __state_type& __state) : _Base_type(__state) { }
public:
+ future() : _Base_type() { }
+
/// Move constructor
- unique_future(unique_future&& __uf) : _Base_type(std::move(__uf)) { }
+ future(future&& __uf) : _Base_type(std::move(__uf)) { }
// Disable copying
- unique_future(const unique_future&) = delete;
- unique_future& operator=(const unique_future&) = delete;
+ 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() { this->_M_get_result(); }
+ get()
+ {
+ typename _Base_type::_Reset __reset(*this);
+ this->_M_get_result();
+ }
};
typedef __basic_future<_Res> _Base_type;
public:
+ shared_future() : _Base_type() { }
+
/// Copy constructor
shared_future(const shared_future& __sf) : _Base_type(__sf) { }
- /// Construct from a unique_future rvalue
- shared_future(unique_future<_Res>&& __uf)
+ /// Construct from a future rvalue
+ shared_future(future<_Res>&& __uf)
: _Base_type(std::move(__uf))
{ }
- shared_future& operator=(const shared_future&) = delete;
+ /// 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;
typedef __basic_future<_Res&> _Base_type;
public:
+ shared_future() : _Base_type() { }
+
/// Copy constructor
shared_future(const shared_future& __sf) : _Base_type(__sf) { }
- /// Construct from a unique_future rvalue
- shared_future(unique_future<_Res&>&& __uf)
+ /// Construct from a future rvalue
+ shared_future(future<_Res&>&& __uf)
: _Base_type(std::move(__uf))
{ }
- shared_future& operator=(const shared_future&) = delete;
+ /// 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_value_ptr; }
+ get() { return this->_M_get_result()._M_get(); }
};
/// Explicit specialization for shared_future<void>
typedef __basic_future<void> _Base_type;
public:
+ shared_future() : _Base_type() { }
+
/// Copy constructor
shared_future(const shared_future& __sf) : _Base_type(__sf) { }
- /// Construct from a unique_future rvalue
- shared_future(unique_future<void>&& __uf)
+ /// Construct from a future rvalue
+ shared_future(future<void>&& __uf)
: _Base_type(std::move(__uf))
{ }
- shared_future& operator=(const shared_future&) = delete;
+ /// 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
{ }
template<typename _Res>
- __basic_future<_Res>::__basic_future(unique_future<_Res>&& __uf)
+ __basic_future<_Res>::__basic_future(shared_future<_Res>&& __sf)
+ : _M_state(std::move(__sf._M_state))
+ { }
+
+ template<typename _Res>
+ __basic_future<_Res>::__basic_future(future<_Res>&& __uf)
: _M_state(std::move(__uf._M_state))
{ }
template<typename _Res>
class promise
{
- template<typename> friend class packaged_task;
-
typedef __future_base::_State _State;
- typedef __future_base::_Result<_Res> result_type;
+ 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;
- typename __future_base::_Ptr<result_type>::type _M_storage;
+ _Ptr_type _M_storage;
public:
promise()
- : _M_future(std::make_shared<_State>()), _M_storage(new result_type())
+ : _M_future(std::make_shared<_State>()), _M_storage(new _Res_type())
{ }
promise(promise&& __rhs)
_M_storage(std::move(__rhs._M_storage))
{ }
- // TODO: requires allocator concepts
+ // TODO: needs allocator_arg_t
/*
template<typename _Allocator>
- promise(allocator_arg_t, const _Allocator& __a);
-
- template<typename _Allocator>
- promise(allocator_arg_t, const _Allocator&, promise&& __rhs);
- */
+ 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;
}
// Retrieving the result
- unique_future<_Res>
+ future<_Res>
get_future()
- { return unique_future<_Res>(_M_future); }
+ { return future<_Res>(_M_future); }
// Setting the result
void
set_value(const _Res& __r)
{
- if (!_M_satisfied())
- _M_storage->_M_set(__r);
- _M_future->_M_set_result(std::move(_M_storage));
+ auto __setter = _State::__setter(this, __r);
+ _M_future->_M_set_result(std::move(__setter));
}
void
set_value(_Res&& __r)
{
- if (!_M_satisfied())
- _M_storage->_M_set(std::move(__r));
- _M_future->_M_set_result(std::move(_M_storage));
+ auto __setter = _State::__setter(this, std::move(__r));
+ _M_future->_M_set_result(std::move(__setter));
}
void
set_exception(exception_ptr __p)
{
- if (!_M_satisfied())
- _M_storage->_M_error = __p;
- _M_future->_M_set_result(std::move(_M_storage));
+ auto __setter = _State::__setter(__p, this);
+ _M_future->_M_set_result(std::move(__setter));
}
-
- private:
- bool _M_satisfied() { return !static_cast<bool>(_M_storage); }
};
/// Partial specialization for promise<R&>
template<typename _Res>
class promise<_Res&>
{
- template<typename> friend class packaged_task;
typedef __future_base::_State _State;
-
- typedef __future_base::_Result<_Res&> result_type;
+ 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;
- typename __future_base::_Ptr<result_type>::type _M_storage;
+ _Ptr_type _M_storage;
public:
promise()
- : _M_future(std::make_shared<_State>()), _M_storage(new result_type())
+ : _M_future(std::make_shared<_State>()), _M_storage(new _Res_type())
{ }
promise(promise&& __rhs)
_M_storage(std::move(__rhs._M_storage))
{ }
- // TODO: requires allocator concepts
+ // TODO: needs allocator_arg_t
/*
template<typename _Allocator>
- promise(allocator_arg_t, const _Allocator& __a);
-
- template<typename _Allocator>
- promise(allocator_arg_t, const _Allocator&, promise&& __rhs);
- */
+ 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;
}
// Retrieving the result
- unique_future<_Res&>
+ future<_Res&>
get_future()
- { return unique_future<_Res&>(_M_future); }
+ { return future<_Res&>(_M_future); }
// Setting the result
void
set_value(_Res& __r)
{
- if (!_M_satisfied())
- _M_storage->_M_value_ptr = &__r;
- _M_future->_M_set_result(std::move(_M_storage));
+ auto __setter = _State::__setter(this, __r);
+ _M_future->_M_set_result(std::move(__setter));
}
void
set_exception(exception_ptr __p)
{
- if (!_M_satisfied())
- _M_storage->_M_error = __p;
- _M_future->_M_set_result(std::move(_M_storage));
+ auto __setter = _State::__setter(__p, this);
+ _M_future->_M_set_result(std::move(__setter));
}
-
- private:
- bool _M_satisfied() { return !static_cast<bool>(_M_storage); }
};
/// Explicit specialization for promise<void>
template<>
class promise<void>
{
- template<typename> friend class packaged_task;
typedef __future_base::_State _State;
- typedef __future_base::_Result<void> result_type;
+ 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<__future_base::_State> _M_future;
- typename __future_base::_Ptr<result_type>::type _M_storage;
+ shared_ptr<_State> _M_future;
+ _Ptr_type _M_storage;
public:
promise()
: _M_future(std::make_shared<_State>()),
- _M_storage(new result_type())
+ _M_storage(new _Res_type())
{ }
promise(promise&& __rhs)
_M_storage(std::move(__rhs._M_storage))
{ }
- // TODO: requires allocator concepts
- /*
- template<typename _Allocator>
- promise(allocator_arg_t, const _Allocator& __a);
+ // TODO: needs allocator_arg_t
+ /*
template<typename _Allocator>
- promise(allocator_arg_t, const _Allocator&, promise&& __rhs);
- */
+ 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;
}
// Retrieving the result
- unique_future<void>
+ future<void>
get_future()
- { return unique_future<void>(_M_future); }
+ { return future<void>(_M_future); }
// Setting the result
+ void set_value();
+
void
- set_value()
+ set_exception(exception_ptr __p)
{
- _M_future->_M_set_result(std::move(_M_storage));
+ auto __setter = _State::__setter(__p, this);
+ _M_future->_M_set_result(std::move(__setter));
}
+ };
- void
- set_exception(exception_ptr __p)
+ // set void
+ template<>
+ struct __future_base::_State::_Setter<void, void>
+ {
+ promise<void>::_Ptr_type operator()()
{
- if (!_M_satisfied())
- _M_storage->_M_error = __p;
- _M_future->_M_set_result(std::move(_M_storage));
+ _State::_S_check(_M_promise->_M_future);
+ return std::move(_M_promise->_M_storage);
}
- private:
- bool _M_satisfied() { return !static_cast<bool>(_M_storage); }
+ promise<void>* _M_promise;
};
- // TODO: requires allocator concepts
+ inline __future_base::_State::_Setter<void, void>
+ __future_base::_State::__setter(promise<void>* __prom)
+ {
+ return _Setter<void, void>{ __prom };
+ }
+
+ inline void
+ promise<void>::set_value()
+ {
+ auto __setter = _State::__setter(this);
+ _M_future->_M_set_result(std::move(__setter));
+ }
+
+ // TODO: needs allocators
/*
template<typename _Res, class Alloc>
- concept_map UsesAllocator<promise<_Res>, Alloc>
- {
- typedef Alloc allocator_type;
- }
- */
- /// Primary template.
- template<typename _Res, typename... _ArgTypes>
- struct _Run_task
+ struct uses_allocator<promise<_Res>, Alloc> : true_type { };
+ */
+
+
+ template<typename _StateT, typename _Res>
+ struct __future_base::_Task_setter
{
- static void
- _S_run(promise<_Res>& __p, function<_Res(_ArgTypes...)>& __f,
- _ArgTypes... __args)
+ typename _StateT::_Ptr_type operator()()
{
- __p.set_value(__f(std::forward<_ArgTypes>(__args)...));
+ __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;
};
- /// Specialization used by packaged_task<void(...)>
- template<typename... _ArgTypes>
- struct _Run_task<void, _ArgTypes...>
+ template<typename _StateT>
+ struct __future_base::_Task_setter<_StateT, void>
{
- static void
- _S_run(promise<void>& __p, function<void(_ArgTypes...)>& __f,
- _ArgTypes... __args)
+ typename _StateT::_Ptr_type operator()()
{
- __f(std::forward<_ArgTypes>(__args)...);
- __p.set_value();
+ __try {
+ _M_fn();
+ } __catch(...) {
+ _M_state->_M_result->_M_error = current_exception();
+ }
+ return std::move(_M_state->_M_result);
}
+ _StateT* _M_state;
+ std::function<void()> _M_fn;
};
+ template<typename _Res, typename... _Args>
+ struct __future_base::_Task_state<_Res(_Args...)> : __future_base::_State
+ {
+ typedef _Res _Res_type;
+
+ _Task_state(std::function<_Res(_Args...)> __task)
+ : _M_result(new _Result<_Res>()), _M_task(std::move(__task))
+ { }
+
+ // TODO: needs allocator_arg_t
+ /*
+ template<typename _Func, typename _Alloc>
+ _Task_state(_Func&& __task, const _Alloc& __a)
+ : _M_result(_S_allocate_result<_Res>(__a))
+ , _M_task(allocator_arg, __a, std::move(__task))
+ { }
+ */
+
+ void
+ _M_run(_Args... __args)
+ {
+ // bound arguments decay so wrap lvalue references
+ auto __bound = std::bind<_Res>(_M_task,
+ _S_maybe_wrap_ref(std::forward<_Args>(__args))...);
+ _Task_setter<_Task_state> __setter{ this, std::move(__bound) };
+ _M_set_result(std::move(__setter));
+ }
+
+ template<typename, typename> friend class _Task_setter;
+ typedef typename __future_base::_Ptr<_Result<_Res>>::type _Ptr_type;
+ _Ptr_type _M_result;
+ std::function<_Res(_Args...)> _M_task;
+
+ template<typename _Tp>
+ static reference_wrapper<_Tp>
+ _S_maybe_wrap_ref(_Tp& __t)
+ { return std::ref(__t); }
+
+ template<typename _Tp>
+ static typename enable_if<!is_lvalue_reference<_Tp>::value,
+ _Tp>::type&&
+ _S_maybe_wrap_ref(_Tp&& __t)
+ { return std::forward<_Tp>(__t); }
+ };
/// packaged_task
template<typename _Res, typename... _ArgTypes>
class packaged_task<_Res(_ArgTypes...)>
{
- function<_Res(_ArgTypes...)> _M_task;
- promise<_Res> _M_promise;
+ typedef __future_base::_Task_state<_Res(_ArgTypes...)> _State_type;
+ shared_ptr<_State_type> _M_state;
public:
typedef _Res result_type;
template<typename _Fn>
explicit
- packaged_task(const _Fn& __fn) : _M_task(__fn) { }
+ packaged_task(const _Fn& __fn)
+ : _M_state(std::make_shared<_State_type>(__fn))
+ { }
template<typename _Fn>
explicit
- packaged_task(_Fn&& __fn) : _M_task(std::move(__fn)) { }
+ packaged_task(_Fn&& __fn)
+ : _M_state(std::make_shared<_State_type>(std::move(__fn)))
+ { }
explicit
- packaged_task(_Res(*__fn)(_ArgTypes...)) : _M_task(__fn) { }
+ packaged_task(_Res(*__fn)(_ArgTypes...))
+ : _M_state(std::make_shared<_State_type>(__fn))
+ { }
- // TODO: requires allocator concepts
+ // TODO: needs allocator_arg_t
/*
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)
+ : _M_state(std::allocate_shared<_State_type>(__a, std::move(__fn)))
{ }
- */
+ */
- ~packaged_task() = default;
+ ~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;
void
swap(packaged_task& __other)
- {
- _M_task.swap(__other._M_task);
- _M_promise.swap(__other._M_promise);
- }
+ { _M_state.swap(__other._M_state); }
- explicit operator bool() const { return static_cast<bool>(_M_task); }
+ explicit operator bool() const { return static_cast<bool>(_M_state); }
// Result retrieval
- unique_future<_Res>
+ future<_Res>
get_future()
- {
- __try
- {
- return _M_promise.get_future();
- }
- __catch (const future_error& __e)
- {
- if (__e.code() == future_errc::future_already_retrieved)
- __throw_bad_function_call();
- __throw_exception_again;
- }
- }
+ { return future<_Res>(_M_state); }
// Execution
void
operator()(_ArgTypes... __args)
{
- if (!static_cast<bool>(_M_task) || _M_promise._M_satisfied())
- __throw_bad_function_call();
+ __future_base::_State::_S_check(_M_state);
+ _M_state->_M_run(std::forward<_ArgTypes>(__args)...);
+ }
- __try
- {
- _Run_task<_Res, _ArgTypes...>::_S_run(_M_promise, _M_task,
- std::forward<_ArgTypes>(__args)...);
- }
- __catch (...)
- {
- _M_promise.set_exception(current_exception());
- }
+ void
+ reset()
+ {
+ __future_base::_State::_S_check(_M_state);
+ packaged_task(std::move(_M_state->_M_task)).swap(*this);
+ }
+ };
+
+ template<typename _Res>
+ class __future_base::_Deferred_state : public __future_base::_State
+ {
+ public:
+ typedef _Res _Res_type;
+
+ explicit
+ _Deferred_state(std::function<_Res()>&& __fn)
+ : _M_result(new _Result<_Res>()), _M_fn(std::move(__fn))
+ { }
+
+ private:
+ template<typename, typename> friend class _Task_setter;
+ typedef typename __future_base::_Ptr<_Result<_Res>>::type _Ptr_type;
+ _Ptr_type _M_result;
+ std::function<_Res()> _M_fn;
+
+ virtual void
+ _M_run_deferred()
+ {
+ _Task_setter<_Deferred_state> __setter{ this, _M_fn };
+ // safe to call multiple times so ignore failure
+ _M_set_result(std::move(__setter), true);
+ }
+ };
+
+ template<typename _Res>
+ class __future_base::_Async_state : public __future_base::_State
+ {
+ public:
+ typedef _Res _Res_type;
+
+ explicit
+ _Async_state(std::function<_Res()>&& __fn)
+ : _M_result(new _Result<_Res>()), _M_fn(std::move(__fn)),
+ _M_thread(mem_fn(&_Async_state::_M_do_run), this)
+ { }
+
+ ~_Async_state() { _M_thread.join(); }
+
+ private:
+ void _M_do_run()
+ {
+ _Task_setter<_Async_state> __setter{ this, std::move(_M_fn) };
+ _M_set_result(std::move(__setter));
}
- void reset() { promise<_Res>().swap(_M_promise); }
+ template<typename, typename> friend class _Task_setter;
+ typedef typename __future_base::_Ptr<_Result<_Res>>::type _Ptr_type;
+ _Ptr_type _M_result;
+ std::function<_Res()> _M_fn;
+ thread _M_thread;
};
+ template<typename _Fn, typename... _Args>
+ future<typename _Fn::result_type>
+ async(launch __policy, _Fn&& __fn, _Args&&... __args)
+ {
+ typedef typename _Fn::result_type result_type;
+ std::shared_ptr<__future_base::_State> __state;
+ if (__policy == launch::async)
+ {
+ typedef typename __future_base::_Async_state<result_type> _State;
+ __state = std::make_shared<_State>(std::bind<result_type>(
+ std::forward<_Fn>(__fn), std::forward<_Args>(__args)...));
+ }
+ else
+ {
+ typedef typename __future_base::_Deferred_state<result_type> _State;
+ __state = std::make_shared<_State>(std::bind<result_type>(
+ std::forward<_Fn>(__fn), std::forward<_Args>(__args)...));
+ }
+ return future<result_type>(__state);
+ }
+
+ template<typename _Fn, typename... _Args>
+ future<typename _Fn::result_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
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