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https://github.com/ClickHouse/ClickHouse.git
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203 lines
5.0 KiB
C++
203 lines
5.0 KiB
C++
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#include <iostream>
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#include <cassert>
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#include <iostream>
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#include <string>
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#include <optional>
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#include <Common/Exception.h>
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#include <base/logger_useful.h>
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#include <Poco/ConsoleChannel.h>
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#include <Poco/Logger.h>
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#include <Poco/AutoPtr.h>
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#if defined(__clang__)
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#include <experimental/coroutine>
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template <typename T>
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using coroutine_handle = std::experimental::coroutine_handle<T>;
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using default_coroutine_handle = std::experimental::coroutine_handle<>;
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using suspend_never = std::experimental::suspend_never;
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using suspend_always = std::experimental::suspend_always;
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#else
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#include <coroutine>
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template <typename T>
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using coroutine_handle = std::coroutine_handle<T>;
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using default_coroutine_handle = std::coroutine_handle<>;
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using suspend_never = std::suspend_never;
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using suspend_always = std::suspend_always;
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#endif
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template <typename T>
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struct suspend_never_val
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{
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constexpr bool await_ready() const noexcept { return true; }
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constexpr void await_suspend(default_coroutine_handle) const noexcept {}
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constexpr T await_resume() const noexcept
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{
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std::cout << " ret " << val << std::endl;
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return val;
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}
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T val;
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};
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template <typename T>
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struct resumable
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{
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struct promise_type
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{
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using coro_handle = coroutine_handle<promise_type>;
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auto get_return_object() { return coro_handle::from_promise(*this); }
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auto initial_suspend() { return suspend_never(); }
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auto final_suspend() noexcept { return suspend_never_val<T>{*r->value}; }
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//void return_void() {}
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void return_value(T value_) { r->value = value_; }
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void unhandled_exception()
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{
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DB::tryLogCurrentException("Logger");
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r->exception = std::current_exception();
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}
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explicit promise_type(std::string tag_) : tag(tag_) {}
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~promise_type() { std::cout << "~promise_type " << tag << std::endl; }
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std::string tag;
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coro_handle next;
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resumable * r = nullptr;
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};
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using coro_handle = coroutine_handle<promise_type>;
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bool await_ready() const noexcept { return false; }
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void await_suspend(coro_handle g) noexcept
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{
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std::cout << " await_suspend " << my.promise().tag << std::endl;
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std::cout << " g tag " << g.promise().tag << std::endl;
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g.promise().next = my;
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}
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T await_resume() noexcept
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{
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std::cout << " await_res " << my.promise().tag << std::endl;
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return *value;
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}
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resumable(coro_handle handle) : my(handle), tag(handle.promise().tag)
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{
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assert(handle);
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my.promise().r = this;
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std::cout << " resumable " << tag << std::endl;
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}
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resumable(resumable &) = delete;
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resumable(resumable &&rhs) : my(rhs.my), tag(rhs.tag)
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{
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rhs.my = {};
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std::cout << " resumable&& " << tag << std::endl;
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}
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static bool resume_impl(resumable *r)
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{
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if (r->value)
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return false;
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auto & next = r->my.promise().next;
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if (next)
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{
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if (resume_impl(next.promise().r))
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return true;
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next = {};
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}
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if (!r->value)
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{
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r->my.resume();
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if (r->exception)
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std::rethrow_exception(r->exception);
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}
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return !r->value;
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}
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bool resume()
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{
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return resume_impl(this);
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}
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T res()
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{
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return *value;
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}
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~resumable()
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{
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std::cout << " ~resumable " << tag << std::endl;
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}
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private:
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coro_handle my;
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std::string tag;
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std::optional<T> value;
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std::exception_ptr exception;
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};
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resumable<int> boo(std::string tag)
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{
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std::cout << "x" << std::endl;
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co_await suspend_always();
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std::cout << StackTrace().toString();
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std::cout << "y" << std::endl;
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co_return 1;
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}
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resumable<int> bar(std::string tag)
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{
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std::cout << "a" << std::endl;
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int res1 = co_await boo("boo1");
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std::cout << "b " << res1 << std::endl;
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int res2 = co_await boo("boo2");
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if (res2 == 1)
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throw DB::Exception(1, "hello");
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std::cout << "c " << res2 << std::endl;
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co_return res1 + res2; // 1 + 1 = 2
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}
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resumable<int> foo(std::string tag) {
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std::cout << "Hello" << std::endl;
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auto res1 = co_await bar("bar1");
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std::cout << "Coro " << res1 << std::endl;
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auto res2 = co_await bar("bar2");
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std::cout << "World " << res2 << std::endl;
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co_return res1 * res2; // 2 * 2 = 4
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}
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int main()
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{
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Poco::AutoPtr<Poco::ConsoleChannel> app_channel(new Poco::ConsoleChannel(std::cerr));
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Poco::Logger::root().setChannel(app_channel);
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Poco::Logger::root().setLevel("trace");
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LOG_INFO(&Poco::Logger::get(""), "Starting");
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try
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{
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auto t = foo("foo");
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std::cout << ".. started" << std::endl;
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while (t.resume())
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std::cout << ".. yielded" << std::endl;
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std::cout << ".. done: " << t.res() << std::endl;
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}
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catch (DB::Exception & e)
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{
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std::cout << "Got exception " << e.what() << std::endl;
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std::cout << e.getStackTraceString() << std::endl;
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}
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}
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