mirror of
https://github.com/matrix-construct/construct
synced 2024-11-09 11:31:11 +01:00
d9a4f06bf6
This is not a move to c++17. If the compiler happens to have support for c++17 namespace scope resolution, they have been kind enough to backport it to gnu++14. This limits our support for really old c++14 compilers, but that was limited anyway. GCC 6.1 and clang 3.6 tested.
132 lines
4.5 KiB
C++
132 lines
4.5 KiB
C++
/*
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* charybdis: oh just a little chat server
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* ctx.h: userland context switching (stackful coroutines)
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*
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* Copyright (C) 2016 Charybdis Development Team
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* Copyright (C) 2016 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.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#define HAVE_IRCD_CTX_CTX_H
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///////////////////////////////////////////////////////////////////////////////
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//
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// low-level ctx interface exposure
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//
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namespace ircd::ctx
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{
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struct ctx;
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IRCD_OVERLOAD(threadsafe)
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const uint64_t &id(const ctx &); // Unique ID for context
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string_view name(const ctx &); // User's optional label for context
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const int64_t ¬es(const ctx &); // Peeks at internal semaphore count
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bool finished(const ctx &); // Context function returned (or exception).
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bool started(const ctx &); // Context was ever entered.
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void interrupt(ctx &); // Interrupt the context for termination.
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void strand(ctx &, std::function<void ()>); // Post function to context strand
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void notify(ctx &, threadsafe_t); // Notify context with threadsafety.
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bool notify(ctx &); // Queue a context switch
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void yield(ctx &); // Direct context switch
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}
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///////////////////////////////////////////////////////////////////////////////
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//
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// "this_context" interface relevant to the currently running context
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//
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namespace ircd::ctx
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{
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extern __thread struct ctx *current; // Always set to the currently running context or null
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ctx &cur(); // Convenience for *current (try to use this instead)
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void yield(); // Allow other contexts to run before returning.
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void wait(); // Returns when context notified.
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// Return remaining time if notified; or <= 0 if not, and timeout thrown on throw overloads
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microseconds wait(const microseconds &, const std::nothrow_t &);
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template<class E, class duration> nothrow_overload<E, duration> wait(const duration &);
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template<class E = timeout, class duration> throw_overload<E, duration> wait(const duration &);
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// Returns false if notified; true if time point reached, timeout thrown on throw_overloads
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bool wait_until(const time_point &tp, const std::nothrow_t &);
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template<class E> nothrow_overload<E, bool> wait_until(const time_point &tp);
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template<class E = timeout> throw_overload<E> wait_until(const time_point &tp);
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// Ignores notes. Throws if interrupted.
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void sleep_until(const time_point &tp);
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template<class duration> void sleep(const duration &);
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void sleep(const int &secs);
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}
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inline void
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ircd::ctx::sleep(const int &secs)
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{
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sleep(seconds(secs));
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}
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template<class duration>
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void
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ircd::ctx::sleep(const duration &d)
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{
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sleep_until(steady_clock::now() + d);
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}
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template<class E>
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ircd::throw_overload<E>
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ircd::ctx::wait_until(const time_point &tp)
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{
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if(wait_until<std::nothrow_t>(tp))
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throw E();
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}
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template<class E>
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ircd::nothrow_overload<E, bool>
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ircd::ctx::wait_until(const time_point &tp)
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{
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return wait_until(tp, std::nothrow);
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}
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template<class E,
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class duration>
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ircd::throw_overload<E, duration>
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ircd::ctx::wait(const duration &d)
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{
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const auto ret(wait<std::nothrow_t>(d));
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return ret <= duration(0)? throw E() : ret;
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}
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template<class E,
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class duration>
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ircd::nothrow_overload<E, duration>
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ircd::ctx::wait(const duration &d)
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{
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using std::chrono::duration_cast;
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const auto ret(wait(duration_cast<microseconds>(d), std::nothrow));
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return duration_cast<duration>(ret);
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}
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inline ircd::ctx::ctx &
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ircd::ctx::cur()
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{
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assert(current);
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return *current;
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}
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