| // |
| // detail/impl/scheduler.ipp |
| // ~~~~~~~~~~~~~~~~~~~~~~~~~ |
| // |
| // Copyright (c) 2003-2021 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_IMPL_SCHEDULER_IPP |
| #define BOOST_ASIO_DETAIL_IMPL_SCHEDULER_IPP |
| |
| #if defined(_MSC_VER) && (_MSC_VER >= 1200) |
| # pragma once |
| #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) |
| |
| #include <boost/asio/detail/config.hpp> |
| |
| #include <boost/asio/detail/concurrency_hint.hpp> |
| #include <boost/asio/detail/event.hpp> |
| #include <boost/asio/detail/limits.hpp> |
| #include <boost/asio/detail/reactor.hpp> |
| #include <boost/asio/detail/scheduler.hpp> |
| #include <boost/asio/detail/scheduler_thread_info.hpp> |
| #include <boost/asio/detail/signal_blocker.hpp> |
| |
| #include <boost/asio/detail/push_options.hpp> |
| |
| namespace boost { |
| namespace asio { |
| namespace detail { |
| |
| class scheduler::thread_function |
| { |
| public: |
| explicit thread_function(scheduler* s) |
| : this_(s) |
| { |
| } |
| |
| void operator()() |
| { |
| boost::system::error_code ec; |
| this_->run(ec); |
| } |
| |
| private: |
| scheduler* this_; |
| }; |
| |
| struct scheduler::task_cleanup |
| { |
| ~task_cleanup() |
| { |
| if (this_thread_->private_outstanding_work > 0) |
| { |
| boost::asio::detail::increment( |
| scheduler_->outstanding_work_, |
| this_thread_->private_outstanding_work); |
| } |
| this_thread_->private_outstanding_work = 0; |
| |
| // Enqueue the completed operations and reinsert the task at the end of |
| // the operation queue. |
| lock_->lock(); |
| scheduler_->task_interrupted_ = true; |
| scheduler_->op_queue_.push(this_thread_->private_op_queue); |
| scheduler_->op_queue_.push(&scheduler_->task_operation_); |
| } |
| |
| scheduler* scheduler_; |
| mutex::scoped_lock* lock_; |
| thread_info* this_thread_; |
| }; |
| |
| struct scheduler::work_cleanup |
| { |
| ~work_cleanup() |
| { |
| if (this_thread_->private_outstanding_work > 1) |
| { |
| boost::asio::detail::increment( |
| scheduler_->outstanding_work_, |
| this_thread_->private_outstanding_work - 1); |
| } |
| else if (this_thread_->private_outstanding_work < 1) |
| { |
| scheduler_->work_finished(); |
| } |
| this_thread_->private_outstanding_work = 0; |
| |
| #if defined(BOOST_ASIO_HAS_THREADS) |
| if (!this_thread_->private_op_queue.empty()) |
| { |
| lock_->lock(); |
| scheduler_->op_queue_.push(this_thread_->private_op_queue); |
| } |
| #endif // defined(BOOST_ASIO_HAS_THREADS) |
| } |
| |
| scheduler* scheduler_; |
| mutex::scoped_lock* lock_; |
| thread_info* this_thread_; |
| }; |
| |
| scheduler::scheduler(boost::asio::execution_context& ctx, |
| int concurrency_hint, bool own_thread) |
| : boost::asio::detail::execution_context_service_base<scheduler>(ctx), |
| one_thread_(concurrency_hint == 1 |
| || !BOOST_ASIO_CONCURRENCY_HINT_IS_LOCKING( |
| SCHEDULER, concurrency_hint) |
| || !BOOST_ASIO_CONCURRENCY_HINT_IS_LOCKING( |
| REACTOR_IO, concurrency_hint)), |
| mutex_(BOOST_ASIO_CONCURRENCY_HINT_IS_LOCKING( |
| SCHEDULER, concurrency_hint)), |
| task_(0), |
| task_interrupted_(true), |
| outstanding_work_(0), |
| stopped_(false), |
| shutdown_(false), |
| concurrency_hint_(concurrency_hint), |
| thread_(0) |
| { |
| BOOST_ASIO_HANDLER_TRACKING_INIT; |
| |
| if (own_thread) |
| { |
| ++outstanding_work_; |
| boost::asio::detail::signal_blocker sb; |
| thread_ = new boost::asio::detail::thread(thread_function(this)); |
| } |
| } |
| |
| scheduler::~scheduler() |
| { |
| if (thread_) |
| { |
| mutex::scoped_lock lock(mutex_); |
| shutdown_ = true; |
| stop_all_threads(lock); |
| lock.unlock(); |
| thread_->join(); |
| delete thread_; |
| } |
| } |
| |
| void scheduler::shutdown() |
| { |
| mutex::scoped_lock lock(mutex_); |
| shutdown_ = true; |
| if (thread_) |
| stop_all_threads(lock); |
| lock.unlock(); |
| |
| // Join thread to ensure task operation is returned to queue. |
| if (thread_) |
| { |
| thread_->join(); |
| delete thread_; |
| thread_ = 0; |
| } |
| |
| // Destroy handler objects. |
| while (!op_queue_.empty()) |
| { |
| operation* o = op_queue_.front(); |
| op_queue_.pop(); |
| if (o != &task_operation_) |
| o->destroy(); |
| } |
| |
| // Reset to initial state. |
| task_ = 0; |
| } |
| |
| void scheduler::init_task() |
| { |
| mutex::scoped_lock lock(mutex_); |
| if (!shutdown_ && !task_) |
| { |
| task_ = &use_service<reactor>(this->context()); |
| op_queue_.push(&task_operation_); |
| wake_one_thread_and_unlock(lock); |
| } |
| } |
| |
| std::size_t scheduler::run(boost::system::error_code& ec) |
| { |
| ec = boost::system::error_code(); |
| if (outstanding_work_ == 0) |
| { |
| stop(); |
| return 0; |
| } |
| |
| thread_info this_thread; |
| this_thread.private_outstanding_work = 0; |
| thread_call_stack::context ctx(this, this_thread); |
| |
| mutex::scoped_lock lock(mutex_); |
| |
| std::size_t n = 0; |
| for (; do_run_one(lock, this_thread, ec); lock.lock()) |
| if (n != (std::numeric_limits<std::size_t>::max)()) |
| ++n; |
| return n; |
| } |
| |
| std::size_t scheduler::run_one(boost::system::error_code& ec) |
| { |
| ec = boost::system::error_code(); |
| if (outstanding_work_ == 0) |
| { |
| stop(); |
| return 0; |
| } |
| |
| thread_info this_thread; |
| this_thread.private_outstanding_work = 0; |
| thread_call_stack::context ctx(this, this_thread); |
| |
| mutex::scoped_lock lock(mutex_); |
| |
| return do_run_one(lock, this_thread, ec); |
| } |
| |
| std::size_t scheduler::wait_one(long usec, boost::system::error_code& ec) |
| { |
| ec = boost::system::error_code(); |
| if (outstanding_work_ == 0) |
| { |
| stop(); |
| return 0; |
| } |
| |
| thread_info this_thread; |
| this_thread.private_outstanding_work = 0; |
| thread_call_stack::context ctx(this, this_thread); |
| |
| mutex::scoped_lock lock(mutex_); |
| |
| return do_wait_one(lock, this_thread, usec, ec); |
| } |
| |
| std::size_t scheduler::poll(boost::system::error_code& ec) |
| { |
| ec = boost::system::error_code(); |
| if (outstanding_work_ == 0) |
| { |
| stop(); |
| return 0; |
| } |
| |
| thread_info this_thread; |
| this_thread.private_outstanding_work = 0; |
| thread_call_stack::context ctx(this, this_thread); |
| |
| mutex::scoped_lock lock(mutex_); |
| |
| #if defined(BOOST_ASIO_HAS_THREADS) |
| // We want to support nested calls to poll() and poll_one(), so any handlers |
| // that are already on a thread-private queue need to be put on to the main |
| // queue now. |
| if (one_thread_) |
| if (thread_info* outer_info = static_cast<thread_info*>(ctx.next_by_key())) |
| op_queue_.push(outer_info->private_op_queue); |
| #endif // defined(BOOST_ASIO_HAS_THREADS) |
| |
| std::size_t n = 0; |
| for (; do_poll_one(lock, this_thread, ec); lock.lock()) |
| if (n != (std::numeric_limits<std::size_t>::max)()) |
| ++n; |
| return n; |
| } |
| |
| std::size_t scheduler::poll_one(boost::system::error_code& ec) |
| { |
| ec = boost::system::error_code(); |
| if (outstanding_work_ == 0) |
| { |
| stop(); |
| return 0; |
| } |
| |
| thread_info this_thread; |
| this_thread.private_outstanding_work = 0; |
| thread_call_stack::context ctx(this, this_thread); |
| |
| mutex::scoped_lock lock(mutex_); |
| |
| #if defined(BOOST_ASIO_HAS_THREADS) |
| // We want to support nested calls to poll() and poll_one(), so any handlers |
| // that are already on a thread-private queue need to be put on to the main |
| // queue now. |
| if (one_thread_) |
| if (thread_info* outer_info = static_cast<thread_info*>(ctx.next_by_key())) |
| op_queue_.push(outer_info->private_op_queue); |
| #endif // defined(BOOST_ASIO_HAS_THREADS) |
| |
| return do_poll_one(lock, this_thread, ec); |
| } |
| |
| void scheduler::stop() |
| { |
| mutex::scoped_lock lock(mutex_); |
| stop_all_threads(lock); |
| } |
| |
| bool scheduler::stopped() const |
| { |
| mutex::scoped_lock lock(mutex_); |
| return stopped_; |
| } |
| |
| void scheduler::restart() |
| { |
| mutex::scoped_lock lock(mutex_); |
| stopped_ = false; |
| } |
| |
| void scheduler::compensating_work_started() |
| { |
| thread_info_base* this_thread = thread_call_stack::contains(this); |
| ++static_cast<thread_info*>(this_thread)->private_outstanding_work; |
| } |
| |
| bool scheduler::can_dispatch() |
| { |
| return thread_call_stack::contains(this) != 0; |
| } |
| |
| void scheduler::capture_current_exception() |
| { |
| if (thread_info_base* this_thread = thread_call_stack::contains(this)) |
| this_thread->capture_current_exception(); |
| } |
| |
| void scheduler::post_immediate_completion( |
| scheduler::operation* op, bool is_continuation) |
| { |
| #if defined(BOOST_ASIO_HAS_THREADS) |
| if (one_thread_ || is_continuation) |
| { |
| if (thread_info_base* this_thread = thread_call_stack::contains(this)) |
| { |
| ++static_cast<thread_info*>(this_thread)->private_outstanding_work; |
| static_cast<thread_info*>(this_thread)->private_op_queue.push(op); |
| return; |
| } |
| } |
| #else // defined(BOOST_ASIO_HAS_THREADS) |
| (void)is_continuation; |
| #endif // defined(BOOST_ASIO_HAS_THREADS) |
| |
| work_started(); |
| mutex::scoped_lock lock(mutex_); |
| op_queue_.push(op); |
| wake_one_thread_and_unlock(lock); |
| } |
| |
| void scheduler::post_immediate_completions(std::size_t n, |
| op_queue<scheduler::operation>& ops, bool is_continuation) |
| { |
| #if defined(BOOST_ASIO_HAS_THREADS) |
| if (one_thread_ || is_continuation) |
| { |
| if (thread_info_base* this_thread = thread_call_stack::contains(this)) |
| { |
| static_cast<thread_info*>(this_thread)->private_outstanding_work |
| += static_cast<long>(n); |
| static_cast<thread_info*>(this_thread)->private_op_queue.push(ops); |
| return; |
| } |
| } |
| #else // defined(BOOST_ASIO_HAS_THREADS) |
| (void)is_continuation; |
| #endif // defined(BOOST_ASIO_HAS_THREADS) |
| |
| increment(outstanding_work_, static_cast<long>(n)); |
| mutex::scoped_lock lock(mutex_); |
| op_queue_.push(ops); |
| wake_one_thread_and_unlock(lock); |
| } |
| |
| void scheduler::post_deferred_completion(scheduler::operation* op) |
| { |
| #if defined(BOOST_ASIO_HAS_THREADS) |
| if (one_thread_) |
| { |
| if (thread_info_base* this_thread = thread_call_stack::contains(this)) |
| { |
| static_cast<thread_info*>(this_thread)->private_op_queue.push(op); |
| return; |
| } |
| } |
| #endif // defined(BOOST_ASIO_HAS_THREADS) |
| |
| mutex::scoped_lock lock(mutex_); |
| op_queue_.push(op); |
| wake_one_thread_and_unlock(lock); |
| } |
| |
| void scheduler::post_deferred_completions( |
| op_queue<scheduler::operation>& ops) |
| { |
| if (!ops.empty()) |
| { |
| #if defined(BOOST_ASIO_HAS_THREADS) |
| if (one_thread_) |
| { |
| if (thread_info_base* this_thread = thread_call_stack::contains(this)) |
| { |
| static_cast<thread_info*>(this_thread)->private_op_queue.push(ops); |
| return; |
| } |
| } |
| #endif // defined(BOOST_ASIO_HAS_THREADS) |
| |
| mutex::scoped_lock lock(mutex_); |
| op_queue_.push(ops); |
| wake_one_thread_and_unlock(lock); |
| } |
| } |
| |
| void scheduler::do_dispatch( |
| scheduler::operation* op) |
| { |
| work_started(); |
| mutex::scoped_lock lock(mutex_); |
| op_queue_.push(op); |
| wake_one_thread_and_unlock(lock); |
| } |
| |
| void scheduler::abandon_operations( |
| op_queue<scheduler::operation>& ops) |
| { |
| op_queue<scheduler::operation> ops2; |
| ops2.push(ops); |
| } |
| |
| std::size_t scheduler::do_run_one(mutex::scoped_lock& lock, |
| scheduler::thread_info& this_thread, |
| const boost::system::error_code& ec) |
| { |
| while (!stopped_) |
| { |
| if (!op_queue_.empty()) |
| { |
| // Prepare to execute first handler from queue. |
| operation* o = op_queue_.front(); |
| op_queue_.pop(); |
| bool more_handlers = (!op_queue_.empty()); |
| |
| if (o == &task_operation_) |
| { |
| task_interrupted_ = more_handlers; |
| |
| if (more_handlers && !one_thread_) |
| wakeup_event_.unlock_and_signal_one(lock); |
| else |
| lock.unlock(); |
| |
| task_cleanup on_exit = { this, &lock, &this_thread }; |
| (void)on_exit; |
| |
| // Run the task. May throw an exception. Only block if the operation |
| // queue is empty and we're not polling, otherwise we want to return |
| // as soon as possible. |
| task_->run(more_handlers ? 0 : -1, this_thread.private_op_queue); |
| } |
| else |
| { |
| std::size_t task_result = o->task_result_; |
| |
| if (more_handlers && !one_thread_) |
| wake_one_thread_and_unlock(lock); |
| else |
| lock.unlock(); |
| |
| // Ensure the count of outstanding work is decremented on block exit. |
| work_cleanup on_exit = { this, &lock, &this_thread }; |
| (void)on_exit; |
| |
| // Complete the operation. May throw an exception. Deletes the object. |
| o->complete(this, ec, task_result); |
| this_thread.rethrow_pending_exception(); |
| |
| return 1; |
| } |
| } |
| else |
| { |
| wakeup_event_.clear(lock); |
| wakeup_event_.wait(lock); |
| } |
| } |
| |
| return 0; |
| } |
| |
| std::size_t scheduler::do_wait_one(mutex::scoped_lock& lock, |
| scheduler::thread_info& this_thread, long usec, |
| const boost::system::error_code& ec) |
| { |
| if (stopped_) |
| return 0; |
| |
| operation* o = op_queue_.front(); |
| if (o == 0) |
| { |
| wakeup_event_.clear(lock); |
| wakeup_event_.wait_for_usec(lock, usec); |
| usec = 0; // Wait at most once. |
| o = op_queue_.front(); |
| } |
| |
| if (o == &task_operation_) |
| { |
| op_queue_.pop(); |
| bool more_handlers = (!op_queue_.empty()); |
| |
| task_interrupted_ = more_handlers; |
| |
| if (more_handlers && !one_thread_) |
| wakeup_event_.unlock_and_signal_one(lock); |
| else |
| lock.unlock(); |
| |
| { |
| task_cleanup on_exit = { this, &lock, &this_thread }; |
| (void)on_exit; |
| |
| // Run the task. May throw an exception. Only block if the operation |
| // queue is empty and we're not polling, otherwise we want to return |
| // as soon as possible. |
| task_->run(more_handlers ? 0 : usec, this_thread.private_op_queue); |
| } |
| |
| o = op_queue_.front(); |
| if (o == &task_operation_) |
| { |
| if (!one_thread_) |
| wakeup_event_.maybe_unlock_and_signal_one(lock); |
| return 0; |
| } |
| } |
| |
| if (o == 0) |
| return 0; |
| |
| op_queue_.pop(); |
| bool more_handlers = (!op_queue_.empty()); |
| |
| std::size_t task_result = o->task_result_; |
| |
| if (more_handlers && !one_thread_) |
| wake_one_thread_and_unlock(lock); |
| else |
| lock.unlock(); |
| |
| // Ensure the count of outstanding work is decremented on block exit. |
| work_cleanup on_exit = { this, &lock, &this_thread }; |
| (void)on_exit; |
| |
| // Complete the operation. May throw an exception. Deletes the object. |
| o->complete(this, ec, task_result); |
| this_thread.rethrow_pending_exception(); |
| |
| return 1; |
| } |
| |
| std::size_t scheduler::do_poll_one(mutex::scoped_lock& lock, |
| scheduler::thread_info& this_thread, |
| const boost::system::error_code& ec) |
| { |
| if (stopped_) |
| return 0; |
| |
| operation* o = op_queue_.front(); |
| if (o == &task_operation_) |
| { |
| op_queue_.pop(); |
| lock.unlock(); |
| |
| { |
| task_cleanup c = { this, &lock, &this_thread }; |
| (void)c; |
| |
| // Run the task. May throw an exception. Only block if the operation |
| // queue is empty and we're not polling, otherwise we want to return |
| // as soon as possible. |
| task_->run(0, this_thread.private_op_queue); |
| } |
| |
| o = op_queue_.front(); |
| if (o == &task_operation_) |
| { |
| wakeup_event_.maybe_unlock_and_signal_one(lock); |
| return 0; |
| } |
| } |
| |
| if (o == 0) |
| return 0; |
| |
| op_queue_.pop(); |
| bool more_handlers = (!op_queue_.empty()); |
| |
| std::size_t task_result = o->task_result_; |
| |
| if (more_handlers && !one_thread_) |
| wake_one_thread_and_unlock(lock); |
| else |
| lock.unlock(); |
| |
| // Ensure the count of outstanding work is decremented on block exit. |
| work_cleanup on_exit = { this, &lock, &this_thread }; |
| (void)on_exit; |
| |
| // Complete the operation. May throw an exception. Deletes the object. |
| o->complete(this, ec, task_result); |
| this_thread.rethrow_pending_exception(); |
| |
| return 1; |
| } |
| |
| void scheduler::stop_all_threads( |
| mutex::scoped_lock& lock) |
| { |
| stopped_ = true; |
| wakeup_event_.signal_all(lock); |
| |
| if (!task_interrupted_ && task_) |
| { |
| task_interrupted_ = true; |
| task_->interrupt(); |
| } |
| } |
| |
| void scheduler::wake_one_thread_and_unlock( |
| mutex::scoped_lock& lock) |
| { |
| if (!wakeup_event_.maybe_unlock_and_signal_one(lock)) |
| { |
| if (!task_interrupted_ && task_) |
| { |
| task_interrupted_ = true; |
| task_->interrupt(); |
| } |
| lock.unlock(); |
| } |
| } |
| |
| } // namespace detail |
| } // namespace asio |
| } // namespace boost |
| |
| #include <boost/asio/detail/pop_options.hpp> |
| |
| #endif // BOOST_ASIO_DETAIL_IMPL_SCHEDULER_IPP |