209 lines
6.6 KiB
C++
209 lines
6.6 KiB
C++
//
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// detail/task_io_service.hpp
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// ~~~~~~~~~~~~~~~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2013 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#ifndef BOOST_ASIO_DETAIL_TASK_IO_SERVICE_HPP
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#define BOOST_ASIO_DETAIL_TASK_IO_SERVICE_HPP
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#if defined(_MSC_VER) && (_MSC_VER >= 1200)
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# pragma once
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#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
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#include <boost/asio/detail/config.hpp>
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#if !defined(BOOST_ASIO_HAS_IOCP)
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#include <boost/system/error_code.hpp>
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#include <boost/asio/io_service.hpp>
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#include <boost/asio/detail/atomic_count.hpp>
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#include <boost/asio/detail/call_stack.hpp>
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#include <boost/asio/detail/mutex.hpp>
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#include <boost/asio/detail/op_queue.hpp>
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#include <boost/asio/detail/reactor_fwd.hpp>
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#include <boost/asio/detail/task_io_service_operation.hpp>
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#include <boost/asio/detail/push_options.hpp>
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namespace boost {
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namespace asio {
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namespace detail {
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struct task_io_service_thread_info;
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class task_io_service
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: public boost::asio::detail::service_base<task_io_service>
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{
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public:
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typedef task_io_service_operation operation;
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// Constructor. Specifies the number of concurrent threads that are likely to
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// run the io_service. If set to 1 certain optimisation are performed.
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BOOST_ASIO_DECL task_io_service(boost::asio::io_service& io_service,
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std::size_t concurrency_hint = 0);
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// Destroy all user-defined handler objects owned by the service.
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BOOST_ASIO_DECL void shutdown_service();
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// Initialise the task, if required.
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BOOST_ASIO_DECL void init_task();
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// Run the event loop until interrupted or no more work.
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BOOST_ASIO_DECL std::size_t run(boost::system::error_code& ec);
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// Run until interrupted or one operation is performed.
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BOOST_ASIO_DECL std::size_t run_one(boost::system::error_code& ec);
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// Poll for operations without blocking.
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BOOST_ASIO_DECL std::size_t poll(boost::system::error_code& ec);
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// Poll for one operation without blocking.
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BOOST_ASIO_DECL std::size_t poll_one(boost::system::error_code& ec);
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// Interrupt the event processing loop.
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BOOST_ASIO_DECL void stop();
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// Determine whether the io_service is stopped.
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BOOST_ASIO_DECL bool stopped() const;
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// Reset in preparation for a subsequent run invocation.
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BOOST_ASIO_DECL void reset();
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// Notify that some work has started.
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void work_started()
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{
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++outstanding_work_;
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}
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// Notify that some work has finished.
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void work_finished()
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{
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if (--outstanding_work_ == 0)
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stop();
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}
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// Return whether a handler can be dispatched immediately.
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bool can_dispatch()
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{
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return thread_call_stack::contains(this) != 0;
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}
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// Request invocation of the given handler.
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template <typename Handler>
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void dispatch(Handler& handler);
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// Request invocation of the given handler and return immediately.
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template <typename Handler>
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void post(Handler& handler);
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// Request invocation of the given operation and return immediately. Assumes
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// that work_started() has not yet been called for the operation.
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BOOST_ASIO_DECL void post_immediate_completion(
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operation* op, bool is_continuation);
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// Request invocation of the given operation and return immediately. Assumes
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// that work_started() was previously called for the operation.
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BOOST_ASIO_DECL void post_deferred_completion(operation* op);
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// Request invocation of the given operations and return immediately. Assumes
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// that work_started() was previously called for each operation.
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BOOST_ASIO_DECL void post_deferred_completions(op_queue<operation>& ops);
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// Process unfinished operations as part of a shutdown_service operation.
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// Assumes that work_started() was previously called for the operations.
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BOOST_ASIO_DECL void abandon_operations(op_queue<operation>& ops);
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private:
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// Structure containing information about an idle thread.
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typedef task_io_service_thread_info thread_info;
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// Enqueue the given operation following a failed attempt to dispatch the
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// operation for immediate invocation.
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BOOST_ASIO_DECL void do_dispatch(operation* op);
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// Run at most one operation. May block.
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BOOST_ASIO_DECL std::size_t do_run_one(mutex::scoped_lock& lock,
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thread_info& this_thread, const boost::system::error_code& ec);
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// Poll for at most one operation.
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BOOST_ASIO_DECL std::size_t do_poll_one(mutex::scoped_lock& lock,
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thread_info& this_thread, const boost::system::error_code& ec);
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// Stop the task and all idle threads.
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BOOST_ASIO_DECL void stop_all_threads(mutex::scoped_lock& lock);
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// Wakes a single idle thread and unlocks the mutex. Returns true if an idle
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// thread was found. If there is no idle thread, returns false and leaves the
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// mutex locked.
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BOOST_ASIO_DECL bool wake_one_idle_thread_and_unlock(
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mutex::scoped_lock& lock);
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// Wake a single idle thread, or the task, and always unlock the mutex.
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BOOST_ASIO_DECL void wake_one_thread_and_unlock(
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mutex::scoped_lock& lock);
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// Helper class to perform task-related operations on block exit.
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struct task_cleanup;
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friend struct task_cleanup;
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// Helper class to call work-related operations on block exit.
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struct work_cleanup;
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friend struct work_cleanup;
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// Whether to optimise for single-threaded use cases.
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const bool one_thread_;
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// Mutex to protect access to internal data.
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mutable mutex mutex_;
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// The task to be run by this service.
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reactor* task_;
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// Operation object to represent the position of the task in the queue.
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struct task_operation : operation
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{
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task_operation() : operation(0) {}
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} task_operation_;
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// Whether the task has been interrupted.
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bool task_interrupted_;
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// The count of unfinished work.
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atomic_count outstanding_work_;
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// The queue of handlers that are ready to be delivered.
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op_queue<operation> op_queue_;
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// Flag to indicate that the dispatcher has been stopped.
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bool stopped_;
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// Flag to indicate that the dispatcher has been shut down.
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bool shutdown_;
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// Per-thread call stack to track the state of each thread in the io_service.
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typedef call_stack<task_io_service, thread_info> thread_call_stack;
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// The threads that are currently idle.
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thread_info* first_idle_thread_;
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};
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} // namespace detail
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} // namespace asio
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} // namespace boost
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#include <boost/asio/detail/pop_options.hpp>
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#include <boost/asio/detail/impl/task_io_service.hpp>
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#if defined(BOOST_ASIO_HEADER_ONLY)
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# include <boost/asio/detail/impl/task_io_service.ipp>
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#endif // defined(BOOST_ASIO_HEADER_ONLY)
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#endif // !defined(BOOST_ASIO_HAS_IOCP)
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#endif // BOOST_ASIO_DETAIL_TASK_IO_SERVICE_HPP
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