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#include <chrono>
#include <coroutine>
#include <functional>
#include <iostream>
#include <queue>
#include <string>
#include <thread>

using task = std::function<void(const std::string&)>;

class executor {
private:
std::thread work_thread_;
std::queue<task> tasks_;

public:
void add_task(task t) { tasks_.emplace(std::move(t)); }

void run() {
work_thread_ = std::thread([this]() {
uint64_t times = 1;
std::cout << "executor thread: " << std::this_thread::get_id() << "\n";
while (true) {
auto& task = tasks_.front();
task(std::to_string(times));
times++;
tasks_.pop();

using namespace std::chrono_literals;
std::this_thread::sleep_for(1000ms);
}
});

if (work_thread_.joinable()) {
work_thread_.join();
}
}
};

class coroutine_task {
public:
struct promise_type {
std::suspend_never initial_suspend() noexcept { return {}; }

std::suspend_always final_suspend() noexcept { return {}; }

void unhandled_exception() noexcept {}

coroutine_task get_return_object() noexcept {
auto tk = coroutine_task{
std::coroutine_handle<promise_type>::from_promise(*this) };
return tk;
}

/*void return_value(int v) noexcept {}*/
void return_void() noexcept {}

std::suspend_always yield_value(std::string&& from) noexcept {
value_ = std::move(from);
return {};
}

std::string value_;
};

private:
std::coroutine_handle<promise_type> coro_;

public:
coroutine_task(std::coroutine_handle<promise_type> h) : coro_(h) {}

~coroutine_task() {
if (coro_) {
coro_.destroy();
}
}

std::string value() { return coro_.promise().value_; }
};

template <typename R, typename Executor = executor>
struct awaitable {
private:
R buf_;
Executor& e_;
std::coroutine_handle<> coro_handle_;

public:
awaitable(Executor& e) : e_(e) {}

bool await_ready() noexcept { return false; }

R await_resume() noexcept { return buf_; }

void await_suspend(std::coroutine_handle<> p) noexcept {
coro_handle_ = p;
}

void async_start() {
e_.add_task([this](const R& times) {
std::cout << "async resume thread: " << std::this_thread::get_id() << "\n";
buf_ = times;
coro_handle_.resume();
});
}
};

auto async_read(executor& e) {
awaitable<std::string> aw{ e };
aw.async_start();
return aw;
}

coroutine_task coro_read1(executor& e) {
std::cout << "coro_read1 begin thread: " << std::this_thread::get_id() << "\n";
for (;;) {
auto value = co_await async_read(e);
std::cout << "1、coro_read1: " << value << " thread: " << std::this_thread::get_id() << "\n";
value = co_await async_read(e);
std::cout << "2、coro_read1: " << value << " thread: " << std::this_thread::get_id() << "\n";
}
}

coroutine_task coro_read2(executor& e) {
std::cout << "coro_read2 begin thread: " << std::this_thread::get_id() << "\n";
for (;;) {
auto value = co_await async_read(e);
std::cout << "coro_read2: " << value << " thread: " << std::this_thread::get_id() << "\n";
}
}

int main() {
executor e;

auto cr1 = coro_read1(e);
auto cr2 = coro_read2(e);

e.run();
return 0;
}
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