128 lines
2.9 KiB
C++
128 lines
2.9 KiB
C++
#pragma once
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#include <chrono>
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#include <coroutine>
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#include <utility>
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namespace async {
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template<typename T = void>
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struct task {
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struct promise_type;
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using handle_type = std::coroutine_handle<promise_type>;
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struct maybe_suspend {
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bool await_ready() noexcept(true) { return !parent; }
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void await_suspend(std::coroutine_handle<>) noexcept(true) {
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if (parent) {
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parent();
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}
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}
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void await_resume() noexcept(true) { }
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std::coroutine_handle<> parent;
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};
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struct promise_type {
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task get_return_object() { return {.h = handle_type::from_promise(*this)}; }
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std::suspend_always initial_suspend() noexcept { return {}; }
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maybe_suspend final_suspend() noexcept { return { .parent = parent }; }
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void return_value(T&& value) { ret_value = std::move(value); }
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void unhandled_exception() {}
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T ret_value;
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std::coroutine_handle<> parent;
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};
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// awaitable
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bool await_ready() { return h.done(); }
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void await_suspend(std::coroutine_handle<> ha) {
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h();
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h.promise().parent = ha;
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}
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T await_resume() { return std::move(h.promise().ret_value); }
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std::coroutine_handle<promise_type> h;
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};
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template<>
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struct task<void> {
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struct promise_type;
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using handle_type = std::coroutine_handle<promise_type>;
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struct maybe_suspend {
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bool await_ready() noexcept(true) { return !parent; }
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void await_suspend(std::coroutine_handle<>) noexcept(true) {
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if (parent) {
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parent();
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}
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}
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void await_resume() noexcept(true) { }
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std::coroutine_handle<> parent;
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};
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struct promise_type {
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task get_return_object() { return {.h = handle_type::from_promise(*this)}; }
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std::suspend_always initial_suspend() noexcept { return {}; }
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maybe_suspend final_suspend() noexcept { return { .parent = parent }; }
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void return_void() {}
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void unhandled_exception() {}
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std::coroutine_handle<> parent;
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};
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// awaitable
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bool await_ready() { return h.done(); }
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void await_suspend(std::coroutine_handle<> ha) {
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h();
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h.promise().parent = ha;
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}
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void await_resume() {}
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std::coroutine_handle<promise_type> h;
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};
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enum class AwaitableType {
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kUnknown = 0,
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kUartRx = 1,
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kNumTypes
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};
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void schedule(std::coroutine_handle<> h, int ms = 0);
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void enqueue(std::coroutine_handle<> h, AwaitableType type);
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void resume(AwaitableType type); // typically called from an ISR
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void main_loop(void (*idle_function)());
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inline auto await(AwaitableType type) {
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struct awaitable {
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AwaitableType type;
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bool await_ready() { return false; };
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void await_suspend(std::coroutine_handle<> h) {
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enqueue(h, type);
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}
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void await_resume() {}
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};
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return awaitable{type};
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}
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inline auto delay(int ms) {
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struct awaitable {
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int ms;
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bool await_ready() { return false; };
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void await_suspend(std::coroutine_handle<> h) {
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schedule(h, ms);
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}
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void await_resume() {}
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};
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return awaitable{ms};
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}
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} // namespace async
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