cooperative.h

#pragma once
#include "prepared_coro.h"
 
#include <optional>
#include <queue>
 
namespace coro {
 
 
class suspend : public trace::suspend_always{
public:
 
 
    static void await_suspend(std::coroutine_handle<> h) {
        if (local_queue) {
            local_queue->push(h);
        } else {
            std::queue<prepared_coro> q;
            local_queue = &q;
            trace::resume(h);
            while (!q.empty()) {
                auto n = std::move(q.front());
                q.pop();
                n();
            }
            local_queue = nullptr;
        }
    }
 
 
    friend bool in_cooperative_mode() {
        return local_queue != nullptr;
    }
 
 
    friend void enqueue(prepared_coro c) {
        await_suspend(c.symmetric_transfer());
    }
 
 
 
protected:
    static thread_local std::queue<prepared_coro> *local_queue;
};
 
 
inline thread_local std::queue<prepared_coro> *suspend::local_queue = nullptr;
 
 
 
}