Chris@16: //
Chris@16: // detail/impl/task_io_service.ipp
Chris@16: // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Chris@16: //
Chris@101: // Copyright (c) 2003-2015 Christopher M. Kohlhoff (chris at kohlhoff dot com)
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16: // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: 
Chris@16: #ifndef BOOST_ASIO_DETAIL_IMPL_TASK_IO_SERVICE_IPP
Chris@16: #define BOOST_ASIO_DETAIL_IMPL_TASK_IO_SERVICE_IPP
Chris@16: 
Chris@16: #if defined(_MSC_VER) && (_MSC_VER >= 1200)
Chris@16: # pragma once
Chris@16: #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
Chris@16: 
Chris@16: #include <boost/asio/detail/config.hpp>
Chris@16: 
Chris@16: #if !defined(BOOST_ASIO_HAS_IOCP)
Chris@16: 
Chris@16: #include <boost/asio/detail/event.hpp>
Chris@16: #include <boost/asio/detail/limits.hpp>
Chris@16: #include <boost/asio/detail/reactor.hpp>
Chris@16: #include <boost/asio/detail/task_io_service.hpp>
Chris@16: #include <boost/asio/detail/task_io_service_thread_info.hpp>
Chris@16: 
Chris@16: #include <boost/asio/detail/push_options.hpp>
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace asio {
Chris@16: namespace detail {
Chris@16: 
Chris@16: struct task_io_service::task_cleanup
Chris@16: {
Chris@16:   ~task_cleanup()
Chris@16:   {
Chris@16:     if (this_thread_->private_outstanding_work > 0)
Chris@16:     {
Chris@16:       boost::asio::detail::increment(
Chris@16:           task_io_service_->outstanding_work_,
Chris@16:           this_thread_->private_outstanding_work);
Chris@16:     }
Chris@16:     this_thread_->private_outstanding_work = 0;
Chris@16: 
Chris@16:     // Enqueue the completed operations and reinsert the task at the end of
Chris@16:     // the operation queue.
Chris@16:     lock_->lock();
Chris@16:     task_io_service_->task_interrupted_ = true;
Chris@16:     task_io_service_->op_queue_.push(this_thread_->private_op_queue);
Chris@16:     task_io_service_->op_queue_.push(&task_io_service_->task_operation_);
Chris@16:   }
Chris@16: 
Chris@16:   task_io_service* task_io_service_;
Chris@16:   mutex::scoped_lock* lock_;
Chris@16:   thread_info* this_thread_;
Chris@16: };
Chris@16: 
Chris@16: struct task_io_service::work_cleanup
Chris@16: {
Chris@16:   ~work_cleanup()
Chris@16:   {
Chris@16:     if (this_thread_->private_outstanding_work > 1)
Chris@16:     {
Chris@16:       boost::asio::detail::increment(
Chris@16:           task_io_service_->outstanding_work_,
Chris@16:           this_thread_->private_outstanding_work - 1);
Chris@16:     }
Chris@16:     else if (this_thread_->private_outstanding_work < 1)
Chris@16:     {
Chris@16:       task_io_service_->work_finished();
Chris@16:     }
Chris@16:     this_thread_->private_outstanding_work = 0;
Chris@16: 
Chris@16: #if defined(BOOST_ASIO_HAS_THREADS)
Chris@16:     if (!this_thread_->private_op_queue.empty())
Chris@16:     {
Chris@16:       lock_->lock();
Chris@16:       task_io_service_->op_queue_.push(this_thread_->private_op_queue);
Chris@16:     }
Chris@16: #endif // defined(BOOST_ASIO_HAS_THREADS)
Chris@16:   }
Chris@16: 
Chris@16:   task_io_service* task_io_service_;
Chris@16:   mutex::scoped_lock* lock_;
Chris@16:   thread_info* this_thread_;
Chris@16: };
Chris@16: 
Chris@16: task_io_service::task_io_service(
Chris@16:     boost::asio::io_service& io_service, std::size_t concurrency_hint)
Chris@16:   : boost::asio::detail::service_base<task_io_service>(io_service),
Chris@16:     one_thread_(concurrency_hint == 1),
Chris@16:     mutex_(),
Chris@16:     task_(0),
Chris@16:     task_interrupted_(true),
Chris@16:     outstanding_work_(0),
Chris@16:     stopped_(false),
Chris@101:     shutdown_(false)
Chris@16: {
Chris@16:   BOOST_ASIO_HANDLER_TRACKING_INIT;
Chris@16: }
Chris@16: 
Chris@16: void task_io_service::shutdown_service()
Chris@16: {
Chris@16:   mutex::scoped_lock lock(mutex_);
Chris@16:   shutdown_ = true;
Chris@16:   lock.unlock();
Chris@16: 
Chris@16:   // Destroy handler objects.
Chris@16:   while (!op_queue_.empty())
Chris@16:   {
Chris@16:     operation* o = op_queue_.front();
Chris@16:     op_queue_.pop();
Chris@16:     if (o != &task_operation_)
Chris@16:       o->destroy();
Chris@16:   }
Chris@16: 
Chris@16:   // Reset to initial state.
Chris@16:   task_ = 0;
Chris@16: }
Chris@16: 
Chris@16: void task_io_service::init_task()
Chris@16: {
Chris@16:   mutex::scoped_lock lock(mutex_);
Chris@16:   if (!shutdown_ && !task_)
Chris@16:   {
Chris@16:     task_ = &use_service<reactor>(this->get_io_service());
Chris@16:     op_queue_.push(&task_operation_);
Chris@16:     wake_one_thread_and_unlock(lock);
Chris@16:   }
Chris@16: }
Chris@16: 
Chris@16: std::size_t task_io_service::run(boost::system::error_code& ec)
Chris@16: {
Chris@16:   ec = boost::system::error_code();
Chris@16:   if (outstanding_work_ == 0)
Chris@16:   {
Chris@16:     stop();
Chris@16:     return 0;
Chris@16:   }
Chris@16: 
Chris@16:   thread_info this_thread;
Chris@16:   this_thread.private_outstanding_work = 0;
Chris@16:   thread_call_stack::context ctx(this, this_thread);
Chris@16: 
Chris@16:   mutex::scoped_lock lock(mutex_);
Chris@16: 
Chris@16:   std::size_t n = 0;
Chris@16:   for (; do_run_one(lock, this_thread, ec); lock.lock())
Chris@16:     if (n != (std::numeric_limits<std::size_t>::max)())
Chris@16:       ++n;
Chris@16:   return n;
Chris@16: }
Chris@16: 
Chris@16: std::size_t task_io_service::run_one(boost::system::error_code& ec)
Chris@16: {
Chris@16:   ec = boost::system::error_code();
Chris@16:   if (outstanding_work_ == 0)
Chris@16:   {
Chris@16:     stop();
Chris@16:     return 0;
Chris@16:   }
Chris@16: 
Chris@16:   thread_info this_thread;
Chris@16:   this_thread.private_outstanding_work = 0;
Chris@16:   thread_call_stack::context ctx(this, this_thread);
Chris@16: 
Chris@16:   mutex::scoped_lock lock(mutex_);
Chris@16: 
Chris@16:   return do_run_one(lock, this_thread, ec);
Chris@16: }
Chris@16: 
Chris@16: std::size_t task_io_service::poll(boost::system::error_code& ec)
Chris@16: {
Chris@16:   ec = boost::system::error_code();
Chris@16:   if (outstanding_work_ == 0)
Chris@16:   {
Chris@16:     stop();
Chris@16:     return 0;
Chris@16:   }
Chris@16: 
Chris@16:   thread_info this_thread;
Chris@16:   this_thread.private_outstanding_work = 0;
Chris@16:   thread_call_stack::context ctx(this, this_thread);
Chris@16: 
Chris@16:   mutex::scoped_lock lock(mutex_);
Chris@16: 
Chris@16: #if defined(BOOST_ASIO_HAS_THREADS)
Chris@16:   // We want to support nested calls to poll() and poll_one(), so any handlers
Chris@16:   // that are already on a thread-private queue need to be put on to the main
Chris@16:   // queue now.
Chris@16:   if (one_thread_)
Chris@16:     if (thread_info* outer_thread_info = ctx.next_by_key())
Chris@16:       op_queue_.push(outer_thread_info->private_op_queue);
Chris@16: #endif // defined(BOOST_ASIO_HAS_THREADS)
Chris@16: 
Chris@16:   std::size_t n = 0;
Chris@16:   for (; do_poll_one(lock, this_thread, ec); lock.lock())
Chris@16:     if (n != (std::numeric_limits<std::size_t>::max)())
Chris@16:       ++n;
Chris@16:   return n;
Chris@16: }
Chris@16: 
Chris@16: std::size_t task_io_service::poll_one(boost::system::error_code& ec)
Chris@16: {
Chris@16:   ec = boost::system::error_code();
Chris@16:   if (outstanding_work_ == 0)
Chris@16:   {
Chris@16:     stop();
Chris@16:     return 0;
Chris@16:   }
Chris@16: 
Chris@16:   thread_info this_thread;
Chris@16:   this_thread.private_outstanding_work = 0;
Chris@16:   thread_call_stack::context ctx(this, this_thread);
Chris@16: 
Chris@16:   mutex::scoped_lock lock(mutex_);
Chris@16: 
Chris@16: #if defined(BOOST_ASIO_HAS_THREADS)
Chris@16:   // We want to support nested calls to poll() and poll_one(), so any handlers
Chris@16:   // that are already on a thread-private queue need to be put on to the main
Chris@16:   // queue now.
Chris@16:   if (one_thread_)
Chris@16:     if (thread_info* outer_thread_info = ctx.next_by_key())
Chris@16:       op_queue_.push(outer_thread_info->private_op_queue);
Chris@16: #endif // defined(BOOST_ASIO_HAS_THREADS)
Chris@16: 
Chris@16:   return do_poll_one(lock, this_thread, ec);
Chris@16: }
Chris@16: 
Chris@16: void task_io_service::stop()
Chris@16: {
Chris@16:   mutex::scoped_lock lock(mutex_);
Chris@16:   stop_all_threads(lock);
Chris@16: }
Chris@16: 
Chris@16: bool task_io_service::stopped() const
Chris@16: {
Chris@16:   mutex::scoped_lock lock(mutex_);
Chris@16:   return stopped_;
Chris@16: }
Chris@16: 
Chris@16: void task_io_service::reset()
Chris@16: {
Chris@16:   mutex::scoped_lock lock(mutex_);
Chris@16:   stopped_ = false;
Chris@16: }
Chris@16: 
Chris@16: void task_io_service::post_immediate_completion(
Chris@16:     task_io_service::operation* op, bool is_continuation)
Chris@16: {
Chris@16: #if defined(BOOST_ASIO_HAS_THREADS)
Chris@16:   if (one_thread_ || is_continuation)
Chris@16:   {
Chris@16:     if (thread_info* this_thread = thread_call_stack::contains(this))
Chris@16:     {
Chris@16:       ++this_thread->private_outstanding_work;
Chris@16:       this_thread->private_op_queue.push(op);
Chris@16:       return;
Chris@16:     }
Chris@16:   }
Chris@101: #else // defined(BOOST_ASIO_HAS_THREADS)
Chris@101:   (void)is_continuation;
Chris@16: #endif // defined(BOOST_ASIO_HAS_THREADS)
Chris@16: 
Chris@16:   work_started();
Chris@16:   mutex::scoped_lock lock(mutex_);
Chris@16:   op_queue_.push(op);
Chris@16:   wake_one_thread_and_unlock(lock);
Chris@16: }
Chris@16: 
Chris@16: void task_io_service::post_deferred_completion(task_io_service::operation* op)
Chris@16: {
Chris@16: #if defined(BOOST_ASIO_HAS_THREADS)
Chris@16:   if (one_thread_)
Chris@16:   {
Chris@16:     if (thread_info* this_thread = thread_call_stack::contains(this))
Chris@16:     {
Chris@16:       this_thread->private_op_queue.push(op);
Chris@16:       return;
Chris@16:     }
Chris@16:   }
Chris@16: #endif // defined(BOOST_ASIO_HAS_THREADS)
Chris@16: 
Chris@16:   mutex::scoped_lock lock(mutex_);
Chris@16:   op_queue_.push(op);
Chris@16:   wake_one_thread_and_unlock(lock);
Chris@16: }
Chris@16: 
Chris@16: void task_io_service::post_deferred_completions(
Chris@16:     op_queue<task_io_service::operation>& ops)
Chris@16: {
Chris@16:   if (!ops.empty())
Chris@16:   {
Chris@16: #if defined(BOOST_ASIO_HAS_THREADS)
Chris@16:     if (one_thread_)
Chris@16:     {
Chris@16:       if (thread_info* this_thread = thread_call_stack::contains(this))
Chris@16:       {
Chris@16:         this_thread->private_op_queue.push(ops);
Chris@16:         return;
Chris@16:       }
Chris@16:     }
Chris@16: #endif // defined(BOOST_ASIO_HAS_THREADS)
Chris@16: 
Chris@16:     mutex::scoped_lock lock(mutex_);
Chris@16:     op_queue_.push(ops);
Chris@16:     wake_one_thread_and_unlock(lock);
Chris@16:   }
Chris@16: }
Chris@16: 
Chris@16: void task_io_service::do_dispatch(
Chris@16:     task_io_service::operation* op)
Chris@16: {
Chris@16:   work_started();
Chris@16:   mutex::scoped_lock lock(mutex_);
Chris@16:   op_queue_.push(op);
Chris@16:   wake_one_thread_and_unlock(lock);
Chris@16: }
Chris@16: 
Chris@16: void task_io_service::abandon_operations(
Chris@16:     op_queue<task_io_service::operation>& ops)
Chris@16: {
Chris@16:   op_queue<task_io_service::operation> ops2;
Chris@16:   ops2.push(ops);
Chris@16: }
Chris@16: 
Chris@16: std::size_t task_io_service::do_run_one(mutex::scoped_lock& lock,
Chris@16:     task_io_service::thread_info& this_thread,
Chris@16:     const boost::system::error_code& ec)
Chris@16: {
Chris@16:   while (!stopped_)
Chris@16:   {
Chris@16:     if (!op_queue_.empty())
Chris@16:     {
Chris@16:       // Prepare to execute first handler from queue.
Chris@16:       operation* o = op_queue_.front();
Chris@16:       op_queue_.pop();
Chris@16:       bool more_handlers = (!op_queue_.empty());
Chris@16: 
Chris@16:       if (o == &task_operation_)
Chris@16:       {
Chris@16:         task_interrupted_ = more_handlers;
Chris@16: 
Chris@16:         if (more_handlers && !one_thread_)
Chris@101:           wakeup_event_.unlock_and_signal_one(lock);
Chris@16:         else
Chris@16:           lock.unlock();
Chris@16: 
Chris@16:         task_cleanup on_exit = { this, &lock, &this_thread };
Chris@16:         (void)on_exit;
Chris@16: 
Chris@16:         // Run the task. May throw an exception. Only block if the operation
Chris@16:         // queue is empty and we're not polling, otherwise we want to return
Chris@16:         // as soon as possible.
Chris@16:         task_->run(!more_handlers, this_thread.private_op_queue);
Chris@16:       }
Chris@16:       else
Chris@16:       {
Chris@16:         std::size_t task_result = o->task_result_;
Chris@16: 
Chris@16:         if (more_handlers && !one_thread_)
Chris@16:           wake_one_thread_and_unlock(lock);
Chris@16:         else
Chris@16:           lock.unlock();
Chris@16: 
Chris@16:         // Ensure the count of outstanding work is decremented on block exit.
Chris@16:         work_cleanup on_exit = { this, &lock, &this_thread };
Chris@16:         (void)on_exit;
Chris@16: 
Chris@16:         // Complete the operation. May throw an exception. Deletes the object.
Chris@16:         o->complete(*this, ec, task_result);
Chris@16: 
Chris@16:         return 1;
Chris@16:       }
Chris@16:     }
Chris@16:     else
Chris@16:     {
Chris@101:       wakeup_event_.clear(lock);
Chris@101:       wakeup_event_.wait(lock);
Chris@16:     }
Chris@16:   }
Chris@16: 
Chris@16:   return 0;
Chris@16: }
Chris@16: 
Chris@16: std::size_t task_io_service::do_poll_one(mutex::scoped_lock& lock,
Chris@16:     task_io_service::thread_info& this_thread,
Chris@16:     const boost::system::error_code& ec)
Chris@16: {
Chris@16:   if (stopped_)
Chris@16:     return 0;
Chris@16: 
Chris@16:   operation* o = op_queue_.front();
Chris@16:   if (o == &task_operation_)
Chris@16:   {
Chris@16:     op_queue_.pop();
Chris@16:     lock.unlock();
Chris@16: 
Chris@16:     {
Chris@16:       task_cleanup c = { this, &lock, &this_thread };
Chris@16:       (void)c;
Chris@16: 
Chris@16:       // Run the task. May throw an exception. Only block if the operation
Chris@16:       // queue is empty and we're not polling, otherwise we want to return
Chris@16:       // as soon as possible.
Chris@16:       task_->run(false, this_thread.private_op_queue);
Chris@16:     }
Chris@16: 
Chris@16:     o = op_queue_.front();
Chris@16:     if (o == &task_operation_)
Chris@16:     {
Chris@101:       wakeup_event_.maybe_unlock_and_signal_one(lock);
Chris@16:       return 0;
Chris@16:     }
Chris@16:   }
Chris@16: 
Chris@16:   if (o == 0)
Chris@16:     return 0;
Chris@16: 
Chris@16:   op_queue_.pop();
Chris@16:   bool more_handlers = (!op_queue_.empty());
Chris@16: 
Chris@16:   std::size_t task_result = o->task_result_;
Chris@16: 
Chris@16:   if (more_handlers && !one_thread_)
Chris@16:     wake_one_thread_and_unlock(lock);
Chris@16:   else
Chris@16:     lock.unlock();
Chris@16: 
Chris@16:   // Ensure the count of outstanding work is decremented on block exit.
Chris@16:   work_cleanup on_exit = { this, &lock, &this_thread };
Chris@16:   (void)on_exit;
Chris@16: 
Chris@16:   // Complete the operation. May throw an exception. Deletes the object.
Chris@16:   o->complete(*this, ec, task_result);
Chris@16: 
Chris@16:   return 1;
Chris@16: }
Chris@16: 
Chris@16: void task_io_service::stop_all_threads(
Chris@16:     mutex::scoped_lock& lock)
Chris@16: {
Chris@16:   stopped_ = true;
Chris@101:   wakeup_event_.signal_all(lock);
Chris@16: 
Chris@16:   if (!task_interrupted_ && task_)
Chris@16:   {
Chris@16:     task_interrupted_ = true;
Chris@16:     task_->interrupt();
Chris@16:   }
Chris@16: }
Chris@16: 
Chris@16: void task_io_service::wake_one_thread_and_unlock(
Chris@16:     mutex::scoped_lock& lock)
Chris@16: {
Chris@101:   if (!wakeup_event_.maybe_unlock_and_signal_one(lock))
Chris@16:   {
Chris@16:     if (!task_interrupted_ && task_)
Chris@16:     {
Chris@16:       task_interrupted_ = true;
Chris@16:       task_->interrupt();
Chris@16:     }
Chris@16:     lock.unlock();
Chris@16:   }
Chris@16: }
Chris@16: 
Chris@16: } // namespace detail
Chris@16: } // namespace asio
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #include <boost/asio/detail/pop_options.hpp>
Chris@16: 
Chris@16: #endif // !defined(BOOST_ASIO_HAS_IOCP)
Chris@16: 
Chris@16: #endif // BOOST_ASIO_DETAIL_IMPL_TASK_IO_SERVICE_IPP