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Diffstat (limited to '3rdParty/Boost/src/boost/asio/detail/dev_poll_reactor.hpp')
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1 files changed, 678 insertions, 0 deletions
diff --git a/3rdParty/Boost/src/boost/asio/detail/dev_poll_reactor.hpp b/3rdParty/Boost/src/boost/asio/detail/dev_poll_reactor.hpp new file mode 100644 index 0000000..8739085 --- /dev/null +++ b/3rdParty/Boost/src/boost/asio/detail/dev_poll_reactor.hpp @@ -0,0 +1,678 @@ +// +// dev_poll_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_DEV_POLL_REACTOR_HPP +#define BOOST_ASIO_DETAIL_DEV_POLL_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/dev_poll_reactor_fwd.hpp> + +#if defined(BOOST_ASIO_HAS_DEV_POLL) + +#include <boost/asio/detail/push_options.hpp> +#include <cstddef> +#include <vector> +#include <boost/config.hpp> +#include <boost/date_time/posix_time/posix_time_types.hpp> +#include <boost/throw_exception.hpp> +#include <sys/devpoll.h> +#include <boost/system/system_error.hpp> +#include <boost/asio/detail/pop_options.hpp> + +#include <boost/asio/error.hpp> +#include <boost/asio/io_service.hpp> +#include <boost/asio/detail/bind_handler.hpp> +#include <boost/asio/detail/hash_map.hpp> +#include <boost/asio/detail/mutex.hpp> +#include <boost/asio/detail/task_io_service.hpp> +#include <boost/asio/detail/thread.hpp> +#include <boost/asio/detail/reactor_op_queue.hpp> +#include <boost/asio/detail/select_interrupter.hpp> +#include <boost/asio/detail/service_base.hpp> +#include <boost/asio/detail/signal_blocker.hpp> +#include <boost/asio/detail/socket_types.hpp> +#include <boost/asio/detail/timer_queue.hpp> + +namespace boost { +namespace asio { +namespace detail { + +template <bool Own_Thread> +class dev_poll_reactor + : public boost::asio::detail::service_base<dev_poll_reactor<Own_Thread> > +{ +public: + // Per-descriptor data. + struct per_descriptor_data + { + }; + + // Constructor. + dev_poll_reactor(boost::asio::io_service& io_service) + : boost::asio::detail::service_base< + dev_poll_reactor<Own_Thread> >(io_service), + mutex_(), + dev_poll_fd_(do_dev_poll_create()), + wait_in_progress_(false), + interrupter_(), + read_op_queue_(), + write_op_queue_(), + except_op_queue_(), + pending_cancellations_(), + stop_thread_(false), + thread_(0), + shutdown_(false) + { + // Start the reactor's internal thread only if needed. + if (Own_Thread) + { + boost::asio::detail::signal_blocker sb; + thread_ = new boost::asio::detail::thread( + bind_handler(&dev_poll_reactor::call_run_thread, this)); + } + + // Add the interrupter's descriptor to /dev/poll. + ::pollfd ev = { 0 }; + ev.fd = interrupter_.read_descriptor(); + ev.events = POLLIN | POLLERR; + ev.revents = 0; + ::write(dev_poll_fd_, &ev, sizeof(ev)); + } + + // Destructor. + ~dev_poll_reactor() + { + shutdown_service(); + ::close(dev_poll_fd_); + } + + // 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<dev_poll_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_) + return; + + if (allow_speculative_read) + { + if (!read_op_queue_.has_operation(descriptor)) + { + boost::system::error_code ec; + std::size_t bytes_transferred = 0; + if (handler.perform(ec, bytes_transferred)) + { + handler.complete(ec, bytes_transferred); + return; + } + } + } + + if (read_op_queue_.enqueue_operation(descriptor, handler)) + { + ::pollfd& ev = add_pending_event_change(descriptor); + ev.events = POLLIN | POLLERR | POLLHUP; + if (write_op_queue_.has_operation(descriptor)) + ev.events |= POLLOUT; + if (except_op_queue_.has_operation(descriptor)) + ev.events |= POLLPRI; + 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_) + return; + + if (allow_speculative_write) + { + if (!write_op_queue_.has_operation(descriptor)) + { + boost::system::error_code ec; + std::size_t bytes_transferred = 0; + if (handler.perform(ec, bytes_transferred)) + { + handler.complete(ec, bytes_transferred); + return; + } + } + } + + if (write_op_queue_.enqueue_operation(descriptor, handler)) + { + ::pollfd& ev = add_pending_event_change(descriptor); + ev.events = POLLOUT | POLLERR | POLLHUP; + if (read_op_queue_.has_operation(descriptor)) + ev.events |= POLLIN; + if (except_op_queue_.has_operation(descriptor)) + ev.events |= POLLPRI; + 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_) + return; + + if (except_op_queue_.enqueue_operation(descriptor, handler)) + { + ::pollfd& ev = add_pending_event_change(descriptor); + ev.events = POLLPRI | POLLERR | POLLHUP; + if (read_op_queue_.has_operation(descriptor)) + ev.events |= POLLIN; + if (write_op_queue_.has_operation(descriptor)) + ev.events |= POLLOUT; + interrupter_.interrupt(); + } + } + + // Start a new write operation. The handler object will be invoked when the + // information available, or an error has occurred. + 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_) + return; + + if (write_op_queue_.enqueue_operation(descriptor, handler)) + { + ::pollfd& ev = add_pending_event_change(descriptor); + ev.events = POLLOUT | POLLERR | POLLHUP; + if (read_op_queue_.has_operation(descriptor)) + ev.events |= POLLIN; + if (except_op_queue_.has_operation(descriptor)) + ev.events |= POLLPRI; + 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); + } + + // 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_); + + // Remove the descriptor from /dev/poll. + ::pollfd& ev = add_pending_event_change(descriptor); + ev.events = POLLREMOVE; + interrupter_.interrupt(); + + // Cancel any outstanding operations associated with the descriptor. + 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<dev_poll_reactor<Own_Thread> >; + + // Run /dev/poll 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; + } + + // Write the pending event registration changes to the /dev/poll descriptor. + std::size_t events_size = sizeof(::pollfd) * pending_event_changes_.size(); + errno = 0; + int result = ::write(dev_poll_fd_, + &pending_event_changes_[0], events_size); + if (result != static_cast<int>(events_size)) + { + for (std::size_t i = 0; i < pending_event_changes_.size(); ++i) + { + int descriptor = pending_event_changes_[i].fd; + boost::system::error_code ec = boost::system::error_code( + errno, boost::asio::error::get_system_category()); + read_op_queue_.perform_all_operations(descriptor, ec); + write_op_queue_.perform_all_operations(descriptor, ec); + except_op_queue_.perform_all_operations(descriptor, ec); + } + } + pending_event_changes_.clear(); + pending_event_change_index_.clear(); + + int timeout = block ? get_timeout() : 0; + wait_in_progress_ = true; + lock.unlock(); + + // Block on the /dev/poll descriptor. + ::pollfd events[128] = { { 0 } }; + ::dvpoll dp = { 0 }; + dp.dp_fds = events; + dp.dp_nfds = 128; + dp.dp_timeout = timeout; + int num_events = ::ioctl(dev_poll_fd_, DP_POLL, &dp); + + lock.lock(); + wait_in_progress_ = false; + + // Block signals while performing operations. + boost::asio::detail::signal_blocker sb; + + // Dispatch the waiting events. + for (int i = 0; i < num_events; ++i) + { + int descriptor = events[i].fd; + if (descriptor == interrupter_.read_descriptor()) + { + interrupter_.reset(); + } + else + { + bool more_reads = false; + bool more_writes = false; + bool more_except = false; + boost::system::error_code ec; + + // Exception operations must be processed first to ensure that any + // out-of-band data is read before normal data. + if (events[i].events & (POLLPRI | POLLERR | POLLHUP)) + more_except = except_op_queue_.perform_operation(descriptor, ec); + else + more_except = except_op_queue_.has_operation(descriptor); + + if (events[i].events & (POLLIN | POLLERR | POLLHUP)) + more_reads = read_op_queue_.perform_operation(descriptor, ec); + else + more_reads = read_op_queue_.has_operation(descriptor); + + if (events[i].events & (POLLOUT | POLLERR | POLLHUP)) + more_writes = write_op_queue_.perform_operation(descriptor, ec); + else + more_writes = write_op_queue_.has_operation(descriptor); + + if ((events[i].events & (POLLERR | POLLHUP)) != 0 + && (events[i].events & ~(POLLERR | POLLHUP)) == 0 + && !more_except && !more_reads && !more_writes) + { + // If we have an event and no operations associated with the + // descriptor then we need to delete the descriptor from /dev/poll. + // The poll operation can produce POLLHUP or POLLERR events when there + // is no operation pending, so if we do not remove the descriptor we + // can end up in a tight polling loop. + ::pollfd ev = { 0 }; + ev.fd = descriptor; + ev.events = POLLREMOVE; + ev.revents = 0; + ::write(dev_poll_fd_, &ev, sizeof(ev)); + } + else + { + ::pollfd ev = { 0 }; + ev.fd = descriptor; + ev.events = POLLERR | POLLHUP; + if (more_reads) + ev.events |= POLLIN; + if (more_writes) + ev.events |= POLLOUT; + if (more_except) + ev.events |= POLLPRI; + ev.revents = 0; + int result = ::write(dev_poll_fd_, &ev, sizeof(ev)); + if (result != sizeof(ev)) + { + ec = boost::system::error_code(errno, + boost::asio::error::get_system_category()); + read_op_queue_.perform_all_operations(descriptor, ec); + write_op_queue_.perform_all_operations(descriptor, ec); + except_op_queue_.perform_all_operations(descriptor, ec); + } + } + } + } + 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_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(dev_poll_reactor* reactor) + { + reactor->run_thread(); + } + + // Interrupt the select loop. + void interrupt() + { + interrupter_.interrupt(); + } + + // Create the /dev/poll file descriptor. Throws an exception if the descriptor + // cannot be created. + static int do_dev_poll_create() + { + int fd = ::open("/dev/poll", O_RDWR); + if (fd == -1) + { + boost::throw_exception( + boost::system::system_error( + boost::system::error_code(errno, + boost::asio::error::get_system_category()), + "/dev/poll")); + } + return fd; + } + + // 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 /dev/poll DP_POLL operation. The timeout + // value is returned as a number of milliseconds. A return value of -1 + // indicates that the poll should block indefinitely. + int get_timeout() + { + if (all_timer_queues_are_empty()) + return -1; + + // 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()) + { + int milliseconds = minimum_wait_duration.total_milliseconds(); + return milliseconds > 0 ? milliseconds : 1; + } + else + { + return 0; + } + } + + // 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 dev_poll_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(); + } + + // Add a pending event entry for the given descriptor. + ::pollfd& add_pending_event_change(int descriptor) + { + hash_map<int, std::size_t>::iterator iter + = pending_event_change_index_.find(descriptor); + if (iter == pending_event_change_index_.end()) + { + std::size_t index = pending_event_changes_.size(); + pending_event_changes_.reserve(pending_event_changes_.size() + 1); + pending_event_change_index_.insert(std::make_pair(descriptor, index)); + pending_event_changes_.push_back(::pollfd()); + pending_event_changes_[index].fd = descriptor; + pending_event_changes_[index].revents = 0; + return pending_event_changes_[index]; + } + else + { + return pending_event_changes_[iter->second]; + } + } + + // Mutex to protect access to internal data. + boost::asio::detail::mutex mutex_; + + // The /dev/poll file descriptor. + int dev_poll_fd_; + + // Vector of /dev/poll events waiting to be written to the descriptor. + std::vector< ::pollfd> pending_event_changes_; + + // Hash map to associate a descriptor with a pending event change index. + hash_map<int, std::size_t> pending_event_change_index_; + + // Whether the DP_POLL operation is currently in progress + bool wait_in_progress_; + + // The interrupter is used to break a blocking DP_POLL operation. + 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 except 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 + +#endif // defined(BOOST_ASIO_HAS_DEV_POLL) + +#include <boost/asio/detail/pop_options.hpp> + +#endif // BOOST_ASIO_DETAIL_DEV_POLL_REACTOR_HPP |