Imported existing code

libraries/include/boost/asio/detail/select_reactor.hpp

@@ -0,0 +1,546 @@
+//
+// 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