| #include <asio/ts/executor.hpp> |
| #include <asio/thread_pool.hpp> |
| #include <iostream> |
| #include <string> |
| |
| using asio::bind_executor; |
| using asio::dispatch; |
| using asio::get_associated_executor; |
| using asio::make_work_guard; |
| using asio::post; |
| using asio::system_executor; |
| using asio::thread_pool; |
| |
| // A function to asynchronously read a single line from an input stream. |
| template <class Handler> |
| void async_getline(std::istream& is, Handler handler) |
| { |
| // Create executor_work for the handler's associated executor. |
| auto work = make_work_guard(handler, system_executor()); |
| |
| // Post a function object to do the work asynchronously. |
| post(system_executor(), |
| [&is, work, handler=std::move(handler)]() mutable |
| { |
| std::string line; |
| std::getline(is, line); |
| |
| // Pass the result to the handler, via the associated executor. |
| dispatch(work.get_executor(), |
| [line=std::move(line), handler=std::move(handler)]() mutable |
| { |
| handler(std::move(line)); |
| }); |
| }); |
| } |
| |
| // A function to asynchronously read multiple lines from an input stream. |
| template <class Handler> |
| void async_getlines(std::istream& is, std::string init, Handler handler) |
| { |
| // Get the final handler's associated executor. |
| auto ex = get_associated_executor(handler, system_executor()); |
| |
| // Use the associated executor for each operation in the composition. |
| async_getline(is, |
| bind_executor(ex, |
| [&is, lines=std::move(init), handler=std::move(handler)] |
| (std::string line) mutable |
| { |
| if (line.empty()) |
| handler(lines); |
| else |
| async_getlines(is, lines + line + "\n", std::move(handler)); |
| })); |
| } |
| |
| int main() |
| { |
| thread_pool pool; |
| |
| std::cout << "Enter text, terminating with a blank line:\n"; |
| |
| async_getlines(std::cin, "", |
| bind_executor(pool, [](std::string lines) |
| { |
| std::cout << "Lines:\n" << lines << "\n"; |
| })); |
| |
| pool.join(); |
| } |