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#include <iostream>
#include <exception>
#include <cassert>
#if __has_include("coroutine")
#include <coroutine>
namespace stdcoro = std;
#else
#include <experimental/coroutine>
namespace stdcoro = std::experimental;
#endif
struct footable : stdcoro::suspend_always {
footable() noexcept = default;
~footable() { assert(released); }
footable(const footable&) = delete;
using coro_handle = stdcoro::coroutine_handle<>;
void await_suspend(coro_handle awaiter) noexcept {
std::cout << "suspending to footable " << this << std::endl;
assert(!handle);
handle = awaiter;
}
void await_resume() noexcept {
std::cout << "resuming from footable " << this << std::endl;
assert(handle);
handle = {};
}
void operator()() noexcept {
std::cout << "operator() on " << this << std::endl;
assert(handle);
handle.resume();
handle = {};
}
void release() noexcept { released = true; }
private:
coro_handle handle;
bool released = false;
};
struct footask {
struct promise_type {
using coro_handle = stdcoro::coroutine_handle<promise_type>;
stdcoro::suspend_never initial_suspend() noexcept { return {}; }
stdcoro::suspend_never final_suspend() noexcept { std::cout << "final suspend" << std::endl; return {}; }
void unhandled_exception() {}
void return_void() noexcept { std::cout << "coro returns" << std::endl; }
footask get_return_object() { return footask{ coro_handle::from_promise(*this) }; }
};
footask(promise_type::coro_handle handle) : handle(handle) {}
~footask() { assert(handle.done()); }
promise_type::coro_handle handle;
};
struct bar {
bar() = default;
bar(const bar&) = delete;
footable foo{};
footask task = taskfun();
footask taskfun() noexcept {
std::cout << "coro begin" << std::endl;
co_await foo;
std::cout << "coro end" << std::endl;
}
};
int main() {
bar foobar;
foobar.foo();
assert(foobar.task.handle.done());
std::cout << "releasing" << std::endl;
foobar.foo.release();
std::cout << "done" << std::endl;
return 0;
}
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