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coroutine_01.cpp
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154 lines (138 loc) · 3.73 KB
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/**
* @Author: running-code-pp 3320996652@qq.com
* @Date: 2025-10-18 16:34:22
* @LastEditors: running-code-pp 3320996652@qq.com
* @LastEditTime: 2025-10-18 17:47:25
* @FilePath: \asio-learn-code\src\coroutine\coroutine_01.cpp
* @Description: C++20协程入门示例01
* @Copyright: Copyright (c) 2025 by ${git_name}, All Rights Reserved.
*/
// 定义协程返回值类型
#include <stdio.h>
#include <coroutine>
#include <iostream>
#include <thread>
template<typename T>
struct coro_ret
{
struct promise_type;
using handle_type = std::coroutine_handle<promise_type>;
// 协程句柄
handle_type _coro_handle;
coro_ret(handle_type h) : _coro_handle(h)
{
}
coro_ret(coro_ret&& other) : _coro_handle(other._coro_handle)
{
other._coro_handle = nullptr;
return *this;
}
coro_ret(const coro_ret&) = delete;
~coro_ret()
{
// 销毁协程
if (_coro_handle)
{
_coro_handle.destroy();
}
}
// 恢复协程，返回是否结束
bool move_next()
{
_coro_handle.resume();
return _coro_handle.done();
}
// 获取返回值
T get()
{
return _coro_handle.promise()._return_value;
}
// 定义承诺对象
struct promise_type
{
// 返回值
T _return_value;
// 几个必须定义的接口
// 生成协程函数的返回对象
auto get_return_object()
{
printf("get_return_object was called\n");
return coro_ret{ handle_type::from_promise(*this) };
}
// 确定协程初始化之后的行为，返回等待体
auto initial_suspend()
{
printf("initial_suspend was called\n");
return std::suspend_always{}; // 立即挂起
}
// co_return之后调用的行为
void return_value(T value)
{
printf("return_value was called\n");
_return_value = value;
return;
}
// co_yield之后调用的行为
auto yield_value(T value)
{
printf("yield_value was called\n");
_return_value = value;
return std::suspend_always{}; // 立即挂起
}
// 协程退出时调用的行为
auto final_suspend() noexcept
{
printf("final_suspend was called\n");
return std::suspend_always{}; // 协程结束时挂起
}
void unhandled_exception()
{
std::exit(1);
}
};
};
// 定义协程函数
coro_ret<int> simple_coroutine()
{
printf("coroutine started\n");
co_await std::suspend_never{}; // 不会挂起
printf("1st suspend coroutine\n");
co_await std::suspend_always{}; // 挂起协程
printf("2nd suspend coroutine\n");
co_yield 42; // 挂起协程并返回值42
printf("3rd suspend coroutine\n");
co_yield 100; // 返回值100并结束协程
co_return 200; // 结束协程
}
int main(){
bool done = false;
auto coro_ret = simple_coroutine();
printf("coroutine %s ret =%d\n", done ? "done" : "not done", coro_ret.get());
done = coro_ret.move_next();
printf("coroutine %s ret =%d\n", done ? "done" : "not done", coro_ret.get());
done = coro_ret.move_next();
printf("coroutine %s ret =%d\n", done ? "done" : "not done", coro_ret.get());
done = coro_ret.move_next();
printf("coroutine %s ret =%d\n", done ? "done" : "not done", coro_ret.get());
done = coro_ret.move_next();
printf("coroutine %s ret =%d\n", done ? "done" : "not done", coro_ret.get());
return 0;
}
/*
运行结果：
get_return_object was called
initial_suspend was called
coroutine not done ret =0
coroutine started
1st suspend coroutine
coroutine not done ret =0
2nd suspend coroutine
yield_value was called
coroutine not done ret =42
3rd suspend coroutine
yield_value was called
coroutine not done ret =100
return_value was called
final_suspend was called
coroutine done ret =200
*/