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Diffstat (limited to 'lib/asio/detail/impl/scheduler.ipp')
-rw-r--r-- | lib/asio/detail/impl/scheduler.ipp | 571 |
1 files changed, 571 insertions, 0 deletions
diff --git a/lib/asio/detail/impl/scheduler.ipp b/lib/asio/detail/impl/scheduler.ipp new file mode 100644 index 0000000..35bc678 --- /dev/null +++ b/lib/asio/detail/impl/scheduler.ipp @@ -0,0 +1,571 @@ +// +// detail/impl/scheduler.ipp +// ~~~~~~~~~~~~~~~~~~~~~~~~~ +// +// Copyright (c) 2003-2018 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 ASIO_DETAIL_IMPL_SCHEDULER_IPP +#define ASIO_DETAIL_IMPL_SCHEDULER_IPP + +#if defined(_MSC_VER) && (_MSC_VER >= 1200) +# pragma once +#endif // defined(_MSC_VER) && (_MSC_VER >= 1200) + +#include "asio/detail/config.hpp" + +#include "asio/detail/concurrency_hint.hpp" +#include "asio/detail/event.hpp" +#include "asio/detail/limits.hpp" +#include "asio/detail/reactor.hpp" +#include "asio/detail/scheduler.hpp" +#include "asio/detail/scheduler_thread_info.hpp" + +#include "asio/detail/push_options.hpp" + +namespace asio { +namespace detail { + +struct scheduler::task_cleanup +{ + ~task_cleanup() + { + if (this_thread_->private_outstanding_work > 0) + { + 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) + { + 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(ASIO_HAS_THREADS) + if (!this_thread_->private_op_queue.empty()) + { + lock_->lock(); + scheduler_->op_queue_.push(this_thread_->private_op_queue); + } +#endif // defined(ASIO_HAS_THREADS) + } + + scheduler* scheduler_; + mutex::scoped_lock* lock_; + thread_info* this_thread_; +}; + +scheduler::scheduler( + asio::execution_context& ctx, int concurrency_hint) + : asio::detail::execution_context_service_base<scheduler>(ctx), + one_thread_(concurrency_hint == 1 + || !ASIO_CONCURRENCY_HINT_IS_LOCKING( + SCHEDULER, concurrency_hint) + || !ASIO_CONCURRENCY_HINT_IS_LOCKING( + REACTOR_IO, concurrency_hint)), + mutex_(ASIO_CONCURRENCY_HINT_IS_LOCKING( + SCHEDULER, concurrency_hint)), + task_(0), + task_interrupted_(true), + outstanding_work_(0), + stopped_(false), + shutdown_(false), + concurrency_hint_(concurrency_hint) +{ + ASIO_HANDLER_TRACKING_INIT; +} + +void scheduler::shutdown() +{ + mutex::scoped_lock lock(mutex_); + shutdown_ = true; + lock.unlock(); + + // 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(asio::error_code& ec) +{ + ec = asio::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(asio::error_code& ec) +{ + ec = asio::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, asio::error_code& ec) +{ + ec = asio::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(asio::error_code& ec) +{ + ec = asio::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(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(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(asio::error_code& ec) +{ + ec = asio::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(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(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; +} + +void scheduler::post_immediate_completion( + scheduler::operation* op, bool is_continuation) +{ +#if defined(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(ASIO_HAS_THREADS) + (void)is_continuation; +#endif // defined(ASIO_HAS_THREADS) + + work_started(); + mutex::scoped_lock lock(mutex_); + op_queue_.push(op); + wake_one_thread_and_unlock(lock); +} + +void scheduler::post_deferred_completion(scheduler::operation* op) +{ +#if defined(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(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(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(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 asio::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); + + 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 asio::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); + + return 1; +} + +std::size_t scheduler::do_poll_one(mutex::scoped_lock& lock, + scheduler::thread_info& this_thread, + const asio::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); + + 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 + +#include "asio/detail/pop_options.hpp" + +#endif // ASIO_DETAIL_IMPL_SCHEDULER_IPP |