From d6c95a111c0950757d75496af254e3427e3769b6 Mon Sep 17 00:00:00 2001 From: Vegard Storheil Eriksen Date: Sat, 16 Apr 2022 20:59:36 +0200 Subject: async: Add preliminary time scheduler. --- async/scheduler.h | 43 ++++++++++++++++++++++++++++ async/time_scheduler.h | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 119 insertions(+) create mode 100644 async/time_scheduler.h (limited to 'async') diff --git a/async/scheduler.h b/async/scheduler.h index 0196aa5..bae4890 100644 --- a/async/scheduler.h +++ b/async/scheduler.h @@ -1,6 +1,9 @@ #pragma once #include +#include + +#include struct schedulable { schedulable* next = nullptr; @@ -161,3 +164,43 @@ struct task : public schedulable { task(std::coroutine_handle h) : schedulable(h) {} }; + +struct async_flag : public schedulable { + bool ready; + + async_flag() : ready(false) {} + + bool await_ready() { + return ready; + } + + bool await_suspend(std::coroutine_handle<> h) { + critical_section lock; + + if(ready) { + return false; + } else { + awaiter = h; + return true; + } + } + + void await_resume() { + critical_section lock; + + awaiter = nullptr; + ready = false; + } + + void set() { + if(ready) { + return; + } + + ready = true; + + if(awaiter) { + scheduler.schedule(*this); + } + } +}; diff --git a/async/time_scheduler.h b/async/time_scheduler.h new file mode 100644 index 0000000..e09de16 --- /dev/null +++ b/async/time_scheduler.h @@ -0,0 +1,76 @@ +#pragma once + +#include + +#include "scheduler.h" + +template +struct time_scheduler_t { + struct wakeup_future : public schedulable { + time_scheduler_t& tsched; + Duration time; + wakeup_future(time_scheduler_t& tsched, Duration time) : tsched(tsched), time(time) {} + + bool await_ready() { + return tsched.now >= time; + } + + bool await_suspend(std::coroutine_handle<> h) { + if(tsched.now >= time) { + return false; + } else { + awaiter = h; + tsched.push_wakeup(this); + return true; + } + } + + void await_resume() {} + + void resume() { + scheduler.schedule(*this); + } + }; + + Duration now; + + wakeup_future* wakeup_queue; + + void push_wakeup(wakeup_future* fut) { + wakeup_future** p = &wakeup_queue; + + while((*p) && (*p)->time <= fut->time) { + p = reinterpret_cast(&(*p)->next); + } + + fut->next = *p; + *p = fut; + } + + async_flag tick_flag; + + void tick() { + tick_flag.set(); + } + + task wakeup_task() { + while(1) { + co_await tick_flag; + now++; + + while(wakeup_queue && wakeup_queue->time <= now) { + auto fut = wakeup_queue; + wakeup_queue = static_cast(fut->next); + fut->resume(); + } + } + } + + wakeup_future sleep_until(Duration time) { + return {*this, time}; + } + + wakeup_future sleep(Duration duration) { + return sleep_until(now + duration); + } +}; -- cgit v1.2.3