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//
// detail/task_io_service.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2012 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_TASK_IO_SERVICE_HPP
#define ASIO_DETAIL_TASK_IO_SERVICE_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include "asio/detail/config.hpp"
#if !defined(ASIO_HAS_IOCP)
#include "asio/error_code.hpp"
#include "asio/io_service.hpp"
#include "asio/detail/atomic_count.hpp"
#include "asio/detail/call_stack.hpp"
#include "asio/detail/mutex.hpp"
#include "asio/detail/op_queue.hpp"
#include "asio/detail/reactor_fwd.hpp"
#include "asio/detail/task_io_service_fwd.hpp"
#include "asio/detail/task_io_service_operation.hpp"
#include "asio/detail/push_options.hpp"
namespace asio {
namespace detail {
class task_io_service
: public asio::detail::service_base<task_io_service>
{
public:
typedef task_io_service_operation operation;
// Constructor. Specifies the number of concurrent threads that are likely to
// run the io_service. If set to 1 certain optimisation are performed.
ASIO_DECL task_io_service(asio::io_service& io_service,
std::size_t concurrency_hint = 0);
// Destroy all user-defined handler objects owned by the service.
ASIO_DECL void shutdown_service();
// Initialise the task, if required.
ASIO_DECL void init_task();
// Run the event loop until interrupted or no more work.
ASIO_DECL std::size_t run(asio::error_code& ec);
// Run until interrupted or one operation is performed.
ASIO_DECL std::size_t run_one(asio::error_code& ec);
// Poll for operations without blocking.
ASIO_DECL std::size_t poll(asio::error_code& ec);
// Poll for one operation without blocking.
ASIO_DECL std::size_t poll_one(asio::error_code& ec);
// Interrupt the event processing loop.
ASIO_DECL void stop();
// Determine whether the io_service is stopped.
ASIO_DECL bool stopped() const;
// Reset in preparation for a subsequent run invocation.
ASIO_DECL void reset();
// Notify that some work has started.
void work_started()
{
++outstanding_work_;
}
// Notify that some work has finished.
void work_finished()
{
if (--outstanding_work_ == 0)
stop();
}
// Return whether a handler can be dispatched immediately.
bool can_dispatch()
{
return thread_call_stack::contains(this) != 0;
}
// Request invocation of the given handler.
template <typename Handler>
void dispatch(Handler& handler);
// Request invocation of the given handler and return immediately.
template <typename Handler>
void post(Handler& handler);
// Request invocation of the given operation and return immediately. Assumes
// that work_started() has not yet been called for the operation.
ASIO_DECL void post_immediate_completion(operation* op);
// Request invocation of the given operation and return immediately. Assumes
// that work_started() was previously called for the operation.
ASIO_DECL void post_deferred_completion(operation* op);
// Request invocation of the given operations and return immediately. Assumes
// that work_started() was previously called for each operation.
ASIO_DECL void post_deferred_completions(op_queue<operation>& ops);
// Request invocation of the given operation, preferring the thread-private
// queue if available, and return immediately. Assumes that work_started()
// has not yet been called for the operation.
ASIO_DECL void post_private_immediate_completion(operation* op);
// Request invocation of the given operation, preferring the thread-private
// queue if available, and return immediately. Assumes that work_started()
// was previously called for the operation.
ASIO_DECL void post_private_deferred_completion(operation* op);
// Process unfinished operations as part of a shutdown_service operation.
// Assumes that work_started() was previously called for the operations.
ASIO_DECL void abandon_operations(op_queue<operation>& ops);
private:
// Structure containing information about an idle thread.
typedef task_io_service_thread_info thread_info;
// Request invocation of the given operation, avoiding the thread-private
// queue, and return immediately. Assumes that work_started() has not yet
// been called for the operation.
ASIO_DECL void post_non_private_immediate_completion(operation* op);
// Request invocation of the given operation, avoiding the thread-private
// queue, and return immediately. Assumes that work_started() was previously
// called for the operation.
ASIO_DECL void post_non_private_deferred_completion(operation* op);
// Run at most one operation. May block.
ASIO_DECL std::size_t do_run_one(mutex::scoped_lock& lock,
thread_info& this_thread, const asio::error_code& ec);
// Poll for at most one operation.
ASIO_DECL std::size_t do_poll_one(mutex::scoped_lock& lock,
thread_info& this_thread, const asio::error_code& ec);
// Stop the task and all idle threads.
ASIO_DECL void stop_all_threads(mutex::scoped_lock& lock);
// Wakes a single idle thread and unlocks the mutex. Returns true if an idle
// thread was found. If there is no idle thread, returns false and leaves the
// mutex locked.
ASIO_DECL bool wake_one_idle_thread_and_unlock(
mutex::scoped_lock& lock);
// Wake a single idle thread, or the task, and always unlock the mutex.
ASIO_DECL void wake_one_thread_and_unlock(
mutex::scoped_lock& lock);
// Helper class to perform task-related operations on block exit.
struct task_cleanup;
friend struct task_cleanup;
// Helper class to call work-related operations on block exit.
struct work_cleanup;
friend struct work_cleanup;
// Whether to optimise for single-threaded use cases.
const bool one_thread_;
// Mutex to protect access to internal data.
mutable mutex mutex_;
// The task to be run by this service.
reactor* task_;
// Operation object to represent the position of the task in the queue.
struct task_operation : operation
{
task_operation() : operation(0) {}
} task_operation_;
// Whether the task has been interrupted.
bool task_interrupted_;
// The count of unfinished work.
atomic_count outstanding_work_;
// The queue of handlers that are ready to be delivered.
op_queue<operation> op_queue_;
// Flag to indicate that the dispatcher has been stopped.
bool stopped_;
// Flag to indicate that the dispatcher has been shut down.
bool shutdown_;
// Per-thread call stack to track the state of each thread in the io_service.
typedef call_stack<task_io_service, thread_info> thread_call_stack;
// The threads that are currently idle.
thread_info* first_idle_thread_;
};
} // namespace detail
} // namespace asio
#include "asio/detail/pop_options.hpp"
#include "asio/detail/impl/task_io_service.hpp"
#if defined(ASIO_HEADER_ONLY)
# include "asio/detail/impl/task_io_service.ipp"
#endif // defined(ASIO_HEADER_ONLY)
#endif // !defined(ASIO_HAS_IOCP)
#endif // ASIO_DETAIL_TASK_IO_SERVICE_HPP