| // |
| // select_reactor.hpp |
| // ~~~~~~~~~~~~~~~~~~ |
| // |
| // Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
| // |
| // Distributed under the Boost Software License, Version 1.0. (See accompanying |
| // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| // |
| |
| #ifndef BOOST_ASIO_DETAIL_SELECT_REACTOR_HPP |
| #define BOOST_ASIO_DETAIL_SELECT_REACTOR_HPP |
| |
| #if defined(_MSC_VER) && (_MSC_VER >= 1200) |
| # pragma once |
| #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) |
| |
| #include <boost/asio/detail/push_options.hpp> |
| |
| #include <boost/asio/detail/socket_types.hpp> // Must come before posix_time. |
| |
| #include <boost/asio/detail/push_options.hpp> |
| #include <cstddef> |
| #include <boost/config.hpp> |
| #include <boost/date_time/posix_time/posix_time_types.hpp> |
| #include <boost/shared_ptr.hpp> |
| #include <vector> |
| #include <boost/asio/detail/pop_options.hpp> |
| |
| #include <boost/asio/io_service.hpp> |
| #include <boost/asio/detail/bind_handler.hpp> |
| #include <boost/asio/detail/fd_set_adapter.hpp> |
| #include <boost/asio/detail/mutex.hpp> |
| #include <boost/asio/detail/noncopyable.hpp> |
| #include <boost/asio/detail/reactor_op_queue.hpp> |
| #include <boost/asio/detail/select_interrupter.hpp> |
| #include <boost/asio/detail/select_reactor_fwd.hpp> |
| #include <boost/asio/detail/service_base.hpp> |
| #include <boost/asio/detail/signal_blocker.hpp> |
| #include <boost/asio/detail/socket_ops.hpp> |
| #include <boost/asio/detail/socket_types.hpp> |
| #include <boost/asio/detail/task_io_service.hpp> |
| #include <boost/asio/detail/thread.hpp> |
| #include <boost/asio/detail/timer_queue.hpp> |
| |
| namespace boost { |
| namespace asio { |
| namespace detail { |
| |
| template <bool Own_Thread> |
| class select_reactor |
| : public boost::asio::detail::service_base<select_reactor<Own_Thread> > |
| { |
| public: |
| // Per-descriptor data. |
| struct per_descriptor_data |
| { |
| }; |
| |
| // Constructor. |
| select_reactor(boost::asio::io_service& io_service) |
| : boost::asio::detail::service_base< |
| select_reactor<Own_Thread> >(io_service), |
| mutex_(), |
| select_in_progress_(false), |
| interrupter_(), |
| read_op_queue_(), |
| write_op_queue_(), |
| except_op_queue_(), |
| pending_cancellations_(), |
| stop_thread_(false), |
| thread_(0), |
| shutdown_(false) |
| { |
| if (Own_Thread) |
| { |
| boost::asio::detail::signal_blocker sb; |
| thread_ = new boost::asio::detail::thread( |
| bind_handler(&select_reactor::call_run_thread, this)); |
| } |
| } |
| |
| // Destructor. |
| ~select_reactor() |
| { |
| shutdown_service(); |
| } |
| |
| // Destroy all user-defined handler objects owned by the service. |
| void shutdown_service() |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| shutdown_ = true; |
| stop_thread_ = true; |
| lock.unlock(); |
| |
| if (thread_) |
| { |
| interrupter_.interrupt(); |
| thread_->join(); |
| delete thread_; |
| thread_ = 0; |
| } |
| |
| read_op_queue_.destroy_operations(); |
| write_op_queue_.destroy_operations(); |
| except_op_queue_.destroy_operations(); |
| |
| for (std::size_t i = 0; i < timer_queues_.size(); ++i) |
| timer_queues_[i]->destroy_timers(); |
| timer_queues_.clear(); |
| } |
| |
| // Initialise the task, but only if the reactor is not in its own thread. |
| void init_task() |
| { |
| if (!Own_Thread) |
| { |
| typedef task_io_service<select_reactor<Own_Thread> > task_io_service_type; |
| use_service<task_io_service_type>(this->get_io_service()).init_task(); |
| } |
| } |
| |
| // Register a socket with the reactor. Returns 0 on success, system error |
| // code on failure. |
| int register_descriptor(socket_type, per_descriptor_data&) |
| { |
| return 0; |
| } |
| |
| // Start a new read operation. The handler object will be invoked when the |
| // given descriptor is ready to be read, or an error has occurred. |
| template <typename Handler> |
| void start_read_op(socket_type descriptor, per_descriptor_data&, |
| Handler handler, bool /*allow_speculative_read*/ = true) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| if (!shutdown_) |
| if (read_op_queue_.enqueue_operation(descriptor, handler)) |
| interrupter_.interrupt(); |
| } |
| |
| // Start a new write operation. The handler object will be invoked when the |
| // given descriptor is ready to be written, or an error has occurred. |
| template <typename Handler> |
| void start_write_op(socket_type descriptor, per_descriptor_data&, |
| Handler handler, bool /*allow_speculative_write*/ = true) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| if (!shutdown_) |
| if (write_op_queue_.enqueue_operation(descriptor, handler)) |
| interrupter_.interrupt(); |
| } |
| |
| // Start a new exception operation. The handler object will be invoked when |
| // the given descriptor has exception information, or an error has occurred. |
| template <typename Handler> |
| void start_except_op(socket_type descriptor, |
| per_descriptor_data&, Handler handler) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| if (!shutdown_) |
| if (except_op_queue_.enqueue_operation(descriptor, handler)) |
| interrupter_.interrupt(); |
| } |
| |
| // Wrapper for connect handlers to enable the handler object to be placed |
| // in both the write and the except operation queues, but ensure that only |
| // one of the handlers is called. |
| template <typename Handler> |
| class connect_handler_wrapper |
| { |
| public: |
| connect_handler_wrapper(socket_type descriptor, |
| boost::shared_ptr<bool> completed, |
| select_reactor<Own_Thread>& reactor, Handler handler) |
| : descriptor_(descriptor), |
| completed_(completed), |
| reactor_(reactor), |
| handler_(handler) |
| { |
| } |
| |
| bool perform(boost::system::error_code& ec, |
| std::size_t& bytes_transferred) |
| { |
| // Check whether one of the handlers has already been called. If it has, |
| // then we don't want to do anything in this handler. |
| if (*completed_) |
| { |
| completed_.reset(); // Indicate that this handler should not complete. |
| return true; |
| } |
| |
| // Cancel the other reactor operation for the connection. |
| *completed_ = true; |
| reactor_.enqueue_cancel_ops_unlocked(descriptor_); |
| |
| // Call the contained handler. |
| return handler_.perform(ec, bytes_transferred); |
| } |
| |
| void complete(const boost::system::error_code& ec, |
| std::size_t bytes_transferred) |
| { |
| if (completed_.get()) |
| handler_.complete(ec, bytes_transferred); |
| } |
| |
| private: |
| socket_type descriptor_; |
| boost::shared_ptr<bool> completed_; |
| select_reactor<Own_Thread>& reactor_; |
| Handler handler_; |
| }; |
| |
| // Start new write and exception operations. The handler object will be |
| // invoked when the given descriptor is ready for writing or has exception |
| // information available, or an error has occurred. The handler will be called |
| // only once. |
| template <typename Handler> |
| void start_connect_op(socket_type descriptor, |
| per_descriptor_data&, Handler handler) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| if (!shutdown_) |
| { |
| boost::shared_ptr<bool> completed(new bool(false)); |
| connect_handler_wrapper<Handler> wrapped_handler( |
| descriptor, completed, *this, handler); |
| bool interrupt = write_op_queue_.enqueue_operation( |
| descriptor, wrapped_handler); |
| interrupt = except_op_queue_.enqueue_operation( |
| descriptor, wrapped_handler) || interrupt; |
| if (interrupt) |
| interrupter_.interrupt(); |
| } |
| } |
| |
| // Cancel all operations associated with the given descriptor. The |
| // handlers associated with the descriptor will be invoked with the |
| // operation_aborted error. |
| void cancel_ops(socket_type descriptor, per_descriptor_data&) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| cancel_ops_unlocked(descriptor); |
| } |
| |
| // Enqueue cancellation of all operations associated with the given |
| // descriptor. The handlers associated with the descriptor will be invoked |
| // with the operation_aborted error. This function does not acquire the |
| // select_reactor's mutex, and so should only be used when the reactor lock is |
| // already held. |
| void enqueue_cancel_ops_unlocked(socket_type descriptor) |
| { |
| pending_cancellations_.push_back(descriptor); |
| } |
| |
| // Cancel any operations that are running against the descriptor and remove |
| // its registration from the reactor. |
| void close_descriptor(socket_type descriptor, per_descriptor_data&) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| cancel_ops_unlocked(descriptor); |
| } |
| |
| // Add a new timer queue to the reactor. |
| template <typename Time_Traits> |
| void add_timer_queue(timer_queue<Time_Traits>& timer_queue) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| timer_queues_.push_back(&timer_queue); |
| } |
| |
| // Remove a timer queue from the reactor. |
| template <typename Time_Traits> |
| void remove_timer_queue(timer_queue<Time_Traits>& timer_queue) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| for (std::size_t i = 0; i < timer_queues_.size(); ++i) |
| { |
| if (timer_queues_[i] == &timer_queue) |
| { |
| timer_queues_.erase(timer_queues_.begin() + i); |
| return; |
| } |
| } |
| } |
| |
| // Schedule a timer in the given timer queue to expire at the specified |
| // absolute time. The handler object will be invoked when the timer expires. |
| template <typename Time_Traits, typename Handler> |
| void schedule_timer(timer_queue<Time_Traits>& timer_queue, |
| const typename Time_Traits::time_type& time, Handler handler, void* token) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| if (!shutdown_) |
| if (timer_queue.enqueue_timer(time, handler, token)) |
| interrupter_.interrupt(); |
| } |
| |
| // Cancel the timer associated with the given token. Returns the number of |
| // handlers that have been posted or dispatched. |
| template <typename Time_Traits> |
| std::size_t cancel_timer(timer_queue<Time_Traits>& timer_queue, void* token) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| std::size_t n = timer_queue.cancel_timer(token); |
| if (n > 0) |
| interrupter_.interrupt(); |
| return n; |
| } |
| |
| private: |
| friend class task_io_service<select_reactor<Own_Thread> >; |
| |
| // Run select once until interrupted or events are ready to be dispatched. |
| void run(bool block) |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| |
| // Dispatch any operation cancellations that were made while the select |
| // loop was not running. |
| read_op_queue_.perform_cancellations(); |
| write_op_queue_.perform_cancellations(); |
| except_op_queue_.perform_cancellations(); |
| for (std::size_t i = 0; i < timer_queues_.size(); ++i) |
| timer_queues_[i]->dispatch_cancellations(); |
| |
| // Check if the thread is supposed to stop. |
| if (stop_thread_) |
| { |
| complete_operations_and_timers(lock); |
| return; |
| } |
| |
| // We can return immediately if there's no work to do and the reactor is |
| // not supposed to block. |
| if (!block && read_op_queue_.empty() && write_op_queue_.empty() |
| && except_op_queue_.empty() && all_timer_queues_are_empty()) |
| { |
| complete_operations_and_timers(lock); |
| return; |
| } |
| |
| // Set up the descriptor sets. |
| fd_set_adapter read_fds; |
| read_fds.set(interrupter_.read_descriptor()); |
| read_op_queue_.get_descriptors(read_fds); |
| fd_set_adapter write_fds; |
| write_op_queue_.get_descriptors(write_fds); |
| fd_set_adapter except_fds; |
| except_op_queue_.get_descriptors(except_fds); |
| socket_type max_fd = read_fds.max_descriptor(); |
| if (write_fds.max_descriptor() > max_fd) |
| max_fd = write_fds.max_descriptor(); |
| if (except_fds.max_descriptor() > max_fd) |
| max_fd = except_fds.max_descriptor(); |
| |
| // Block on the select call without holding the lock so that new |
| // operations can be started while the call is executing. |
| timeval tv_buf = { 0, 0 }; |
| timeval* tv = block ? get_timeout(tv_buf) : &tv_buf; |
| select_in_progress_ = true; |
| lock.unlock(); |
| boost::system::error_code ec; |
| int retval = socket_ops::select(static_cast<int>(max_fd + 1), |
| read_fds, write_fds, except_fds, tv, ec); |
| lock.lock(); |
| select_in_progress_ = false; |
| |
| // Block signals while dispatching operations. |
| boost::asio::detail::signal_blocker sb; |
| |
| // Reset the interrupter. |
| if (retval > 0 && read_fds.is_set(interrupter_.read_descriptor())) |
| interrupter_.reset(); |
| |
| // Dispatch all ready operations. |
| if (retval > 0) |
| { |
| // Exception operations must be processed first to ensure that any |
| // out-of-band data is read before normal data. |
| except_op_queue_.perform_operations_for_descriptors( |
| except_fds, boost::system::error_code()); |
| read_op_queue_.perform_operations_for_descriptors( |
| read_fds, boost::system::error_code()); |
| write_op_queue_.perform_operations_for_descriptors( |
| write_fds, boost::system::error_code()); |
| except_op_queue_.perform_cancellations(); |
| read_op_queue_.perform_cancellations(); |
| write_op_queue_.perform_cancellations(); |
| } |
| for (std::size_t i = 0; i < timer_queues_.size(); ++i) |
| { |
| timer_queues_[i]->dispatch_timers(); |
| timer_queues_[i]->dispatch_cancellations(); |
| } |
| |
| // Issue any pending cancellations. |
| for (size_t i = 0; i < pending_cancellations_.size(); ++i) |
| cancel_ops_unlocked(pending_cancellations_[i]); |
| pending_cancellations_.clear(); |
| |
| complete_operations_and_timers(lock); |
| } |
| |
| // Run the select loop in the thread. |
| void run_thread() |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| while (!stop_thread_) |
| { |
| lock.unlock(); |
| run(true); |
| lock.lock(); |
| } |
| } |
| |
| // Entry point for the select loop thread. |
| static void call_run_thread(select_reactor* reactor) |
| { |
| reactor->run_thread(); |
| } |
| |
| // Interrupt the select loop. |
| void interrupt() |
| { |
| interrupter_.interrupt(); |
| } |
| |
| // Check if all timer queues are empty. |
| bool all_timer_queues_are_empty() const |
| { |
| for (std::size_t i = 0; i < timer_queues_.size(); ++i) |
| if (!timer_queues_[i]->empty()) |
| return false; |
| return true; |
| } |
| |
| // Get the timeout value for the select call. |
| timeval* get_timeout(timeval& tv) |
| { |
| if (all_timer_queues_are_empty()) |
| return 0; |
| |
| // By default we will wait no longer than 5 minutes. This will ensure that |
| // any changes to the system clock are detected after no longer than this. |
| boost::posix_time::time_duration minimum_wait_duration |
| = boost::posix_time::minutes(5); |
| |
| for (std::size_t i = 0; i < timer_queues_.size(); ++i) |
| { |
| boost::posix_time::time_duration wait_duration |
| = timer_queues_[i]->wait_duration(); |
| if (wait_duration < minimum_wait_duration) |
| minimum_wait_duration = wait_duration; |
| } |
| |
| if (minimum_wait_duration > boost::posix_time::time_duration()) |
| { |
| tv.tv_sec = minimum_wait_duration.total_seconds(); |
| tv.tv_usec = minimum_wait_duration.total_microseconds() % 1000000; |
| } |
| else |
| { |
| tv.tv_sec = 0; |
| tv.tv_usec = 0; |
| } |
| |
| return &tv; |
| } |
| |
| // Cancel all operations associated with the given descriptor. The do_cancel |
| // function of the handler objects will be invoked. This function does not |
| // acquire the select_reactor's mutex. |
| void cancel_ops_unlocked(socket_type descriptor) |
| { |
| bool interrupt = read_op_queue_.cancel_operations(descriptor); |
| interrupt = write_op_queue_.cancel_operations(descriptor) || interrupt; |
| interrupt = except_op_queue_.cancel_operations(descriptor) || interrupt; |
| if (interrupt) |
| interrupter_.interrupt(); |
| } |
| |
| // Clean up operations and timers. We must not hold the lock since the |
| // destructors may make calls back into this reactor. We make a copy of the |
| // vector of timer queues since the original may be modified while the lock |
| // is not held. |
| void complete_operations_and_timers( |
| boost::asio::detail::mutex::scoped_lock& lock) |
| { |
| timer_queues_for_cleanup_ = timer_queues_; |
| lock.unlock(); |
| read_op_queue_.complete_operations(); |
| write_op_queue_.complete_operations(); |
| except_op_queue_.complete_operations(); |
| for (std::size_t i = 0; i < timer_queues_for_cleanup_.size(); ++i) |
| timer_queues_for_cleanup_[i]->complete_timers(); |
| } |
| |
| // Mutex to protect access to internal data. |
| boost::asio::detail::mutex mutex_; |
| |
| // Whether the select loop is currently running or not. |
| bool select_in_progress_; |
| |
| // The interrupter is used to break a blocking select call. |
| select_interrupter interrupter_; |
| |
| // The queue of read operations. |
| reactor_op_queue<socket_type> read_op_queue_; |
| |
| // The queue of write operations. |
| reactor_op_queue<socket_type> write_op_queue_; |
| |
| // The queue of exception operations. |
| reactor_op_queue<socket_type> except_op_queue_; |
| |
| // The timer queues. |
| std::vector<timer_queue_base*> timer_queues_; |
| |
| // A copy of the timer queues, used when cleaning up timers. The copy is |
| // stored as a class data member to avoid unnecessary memory allocation. |
| std::vector<timer_queue_base*> timer_queues_for_cleanup_; |
| |
| // The descriptors that are pending cancellation. |
| std::vector<socket_type> pending_cancellations_; |
| |
| // Does the reactor loop thread need to stop. |
| bool stop_thread_; |
| |
| // The thread that is running the reactor loop. |
| boost::asio::detail::thread* thread_; |
| |
| // Whether the service has been shut down. |
| bool shutdown_; |
| }; |
| |
| } // namespace detail |
| } // namespace asio |
| } // namespace boost |
| |
| #include <boost/asio/detail/pop_options.hpp> |
| |
| #endif // BOOST_ASIO_DETAIL_SELECT_REACTOR_HPP |