285 lines
7.7 KiB
C++
285 lines
7.7 KiB
C++
// Matrix Construct
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//
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// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies. The
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// full license for this software is available in the LICENSE file.
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#pragma once
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#define HAVE_IRCD_CTX_FUTURE_H
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namespace ircd::ctx
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{
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template<class T = void> class future;
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template<> class future<void>;
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template<class... T> struct scoped_future;
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IRCD_EXCEPTION(future_error, future_already_retrieved)
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IRCD_OVERLOAD(use_future)
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template<class T> const shared_state<T> &state(const future<T> &);
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template<class T> shared_state<T> &state(future<T> &);
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template<class T,
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class time_point>
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bool _wait_until(const future<T> &, const time_point &, std::nothrow_t);
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template<class T,
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class time_point>
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void _wait_until(const future<T> &, const time_point &);
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}
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template<class T>
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struct ircd::ctx::future
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:private shared_state<T>
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{
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using value_type = typename shared_state<T>::value_type;
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using pointer_type = typename shared_state<T>::pointer_type;
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using reference_type = typename shared_state<T>::reference_type;
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const shared_state<T> &state() const { return *this; }
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shared_state<T> &state() { return *this; }
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bool valid() const { return !is(state(), future_state::INVALID); }
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bool operator!() const { return !valid(); }
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std::exception_ptr eptr() const { return state().eptr; }
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string_view what() const { return util::what(eptr()); }
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explicit operator T() { return get(); }
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template<class U, class time_point> friend bool wait_until(const future<U> &, const time_point &, std::nothrow_t);
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template<class U, class time_point> friend void wait_until(const future<U> &, const time_point &);
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template<class time_point> bool wait_until(const time_point &, std::nothrow_t) const;
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template<class time_point> void wait_until(const time_point &) const;
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template<class duration> bool wait(const duration &d, std::nothrow_t) const;
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template<class duration> void wait(const duration &d) const;
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void wait() const;
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T get();
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template<class duration> T get(const duration &d);
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template<class time_point> T get_until(const time_point &);
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using shared_state<T>::shared_state;
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using shared_state<T>::operator=;
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};
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template<>
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struct ircd::ctx::future<void>
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:private shared_state<void>
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{
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using value_type = typename shared_state<void>::value_type;
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const shared_state<void> &state() const { return *this; }
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shared_state<void> &state() { return *this; }
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bool valid() const { return !is(state(), future_state::INVALID); }
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bool operator!() const { return !valid(); }
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std::exception_ptr eptr() const { return state().eptr; }
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string_view what() const { return util::what(eptr()); }
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template<class U, class time_point> friend bool wait_until(const future<U> &, const time_point &, std::nothrow_t);
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template<class U, class time_point> friend void wait_until(const future<U> &, const time_point &);
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template<class time_point> bool wait_until(const time_point &, std::nothrow_t) const;
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template<class time_point> void wait_until(const time_point &) const;
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template<class duration> bool wait(const duration &d, std::nothrow_t) const;
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template<class duration> void wait(const duration &d) const;
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void wait() const;
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using shared_state<void>::shared_state;
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using shared_state<void>::operator=;
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};
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template<class... T>
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struct ircd::ctx::scoped_future
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:future<T...>
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{
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using future<T...>::future;
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~scoped_future() noexcept;
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};
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template<class... T>
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inline
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ircd::ctx::scoped_future<T...>::~scoped_future()
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noexcept
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{
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if(std::uncaught_exceptions() || !this->valid())
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return;
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this->wait();
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}
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template<class T>
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template<class time_point>
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inline T
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ircd::ctx::future<T>::get_until(const time_point &tp)
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{
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this->wait_until(tp);
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return this->get();
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}
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template<class T>
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template<class duration>
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inline T
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ircd::ctx::future<T>::get(const duration &d)
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{
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this->wait(d);
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return this->get();
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}
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template<class T>
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inline T
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ircd::ctx::future<T>::get()
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{
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wait();
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if(unlikely(is(state(), future_state::RETRIEVED)))
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throw future_already_retrieved{};
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set(state(), future_state::RETRIEVED);
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if(bool(state().eptr))
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std::rethrow_exception(state().eptr);
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return std::move(state().val);
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}
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template<class T>
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inline void
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ircd::ctx::future<T>::wait()
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const
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{
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this->wait_until(system_point::max());
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}
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inline void
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ircd::ctx::future<void>::wait()
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const
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{
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this->wait_until(system_point::max());
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}
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template<class T>
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template<class duration>
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inline void
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ircd::ctx::future<T>::wait(const duration &d)
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const
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{
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this->wait_until(now<system_point>() + d);
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}
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template<class duration>
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inline void
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ircd::ctx::future<void>::wait(const duration &d)
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const
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{
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this->wait_until(now<system_point>() + d);
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}
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template<class T>
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template<class duration>
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inline bool
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ircd::ctx::future<T>::wait(const duration &d,
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std::nothrow_t)
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const
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{
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return this->wait_until(now<system_point>() + d, std::nothrow);
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}
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template<class duration>
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inline bool
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ircd::ctx::future<void>::wait(const duration &d,
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std::nothrow_t)
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const
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{
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return this->wait_until(now<system_point>() + d, std::nothrow);
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}
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template<class T>
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template<class time_point>
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inline void
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ircd::ctx::future<T>::wait_until(const time_point &tp)
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const
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{
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if(!this->wait_until(tp, std::nothrow))
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throw timeout{};
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}
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template<class time_point>
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inline void
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ircd::ctx::future<void>::wait_until(const time_point &tp)
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const
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{
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if(!this->wait_until(tp, std::nothrow))
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throw timeout{};
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}
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template<class T>
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template<class time_point>
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inline bool
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ircd::ctx::future<T>::wait_until(const time_point &tp,
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std::nothrow_t)
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const
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{
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return _wait_until(*this, tp, std::nothrow);
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}
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template<class time_point>
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inline bool
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ircd::ctx::future<void>::wait_until(const time_point &tp,
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std::nothrow_t)
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const
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{
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if(_wait_until(*this, tp, std::nothrow))
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{
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auto &state(mutable_cast(this->state()));
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set(state, future_state::RETRIEVED);
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if(bool(state.eptr))
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std::rethrow_exception(state.eptr);
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return true;
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}
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else return false;
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}
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template<class T,
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class time_point>
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inline void
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ircd::ctx::wait_until(const future<T> &f,
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const time_point &tp)
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{
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if(!_wait_until(f, tp, std::nothrow))
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throw timeout{};
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}
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template<class T,
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class time_point>
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inline bool
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ircd::ctx::_wait_until(const future<T> &f,
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const time_point &tp,
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std::nothrow_t)
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{
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auto &state(mutable_cast(f.state()));
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if(unlikely(is(state, future_state::INVALID)))
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throw no_state{};
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return state.cond.wait_until(tp, [&state]() noexcept
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{
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return !is(state, future_state::PENDING);
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});
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}
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template<class T>
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inline ircd::ctx::shared_state<T> &
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ircd::ctx::state(future<T> &future)
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{
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return future.state();
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}
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template<class T>
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inline const ircd::ctx::shared_state<T> &
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ircd::ctx::state(const future<T> &future)
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{
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return future.state();
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}
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