230 lines
7.0 KiB
C++
230 lines
7.0 KiB
C++
//
|
|
// detail/scheduler.hpp
|
|
// ~~~~~~~~~~~~~~~~~~~~
|
|
//
|
|
// 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 ASIO_DETAIL_SCHEDULER_HPP
|
|
#define ASIO_DETAIL_SCHEDULER_HPP
|
|
|
|
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
|
|
# pragma once
|
|
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
|
|
|
|
#include "asio/detail/config.hpp"
|
|
|
|
#include "asio/error_code.hpp"
|
|
#include "asio/execution_context.hpp"
|
|
#include "asio/detail/atomic_count.hpp"
|
|
#include "asio/detail/conditionally_enabled_event.hpp"
|
|
#include "asio/detail/conditionally_enabled_mutex.hpp"
|
|
#include "asio/detail/op_queue.hpp"
|
|
#include "asio/detail/reactor_fwd.hpp"
|
|
#include "asio/detail/scheduler_operation.hpp"
|
|
#include "asio/detail/thread.hpp"
|
|
#include "asio/detail/thread_context.hpp"
|
|
|
|
#include "asio/detail/push_options.hpp"
|
|
|
|
namespace asio {
|
|
namespace detail {
|
|
|
|
struct scheduler_thread_info;
|
|
|
|
class scheduler
|
|
: public execution_context_service_base<scheduler>,
|
|
public thread_context
|
|
{
|
|
public:
|
|
typedef scheduler_operation operation;
|
|
|
|
// Constructor. Specifies the number of concurrent threads that are likely to
|
|
// run the scheduler. If set to 1 certain optimisation are performed.
|
|
ASIO_DECL scheduler(asio::execution_context& ctx,
|
|
int concurrency_hint = 0, bool own_thread = true);
|
|
|
|
// Destructor.
|
|
ASIO_DECL ~scheduler();
|
|
|
|
// Destroy all user-defined handler objects owned by the service.
|
|
ASIO_DECL void shutdown();
|
|
|
|
// 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);
|
|
|
|
// Run until timeout, interrupted, or one operation is performed.
|
|
ASIO_DECL std::size_t wait_one(
|
|
long usec, 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 scheduler is stopped.
|
|
ASIO_DECL bool stopped() const;
|
|
|
|
// Restart in preparation for a subsequent run invocation.
|
|
ASIO_DECL void restart();
|
|
|
|
// Notify that some work has started.
|
|
void work_started()
|
|
{
|
|
++outstanding_work_;
|
|
}
|
|
|
|
// Used to compensate for a forthcoming work_finished call. Must be called
|
|
// from within a scheduler-owned thread.
|
|
ASIO_DECL void compensating_work_started();
|
|
|
|
// Notify that some work has finished.
|
|
void work_finished()
|
|
{
|
|
if (--outstanding_work_ == 0)
|
|
stop();
|
|
}
|
|
|
|
// Return whether a handler can be dispatched immediately.
|
|
ASIO_DECL bool can_dispatch();
|
|
|
|
/// Capture the current exception so it can be rethrown from a run function.
|
|
ASIO_DECL void capture_current_exception();
|
|
|
|
// 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, bool is_continuation);
|
|
|
|
// Request invocation of the given operations and return immediately. Assumes
|
|
// that work_started() has not yet been called for the operations.
|
|
ASIO_DECL void post_immediate_completions(std::size_t n,
|
|
op_queue<operation>& ops, bool is_continuation);
|
|
|
|
// 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);
|
|
|
|
// Enqueue the given operation following a failed attempt to dispatch the
|
|
// operation for immediate invocation.
|
|
ASIO_DECL void do_dispatch(operation* op);
|
|
|
|
// Process unfinished operations as part of a shutdownoperation. Assumes that
|
|
// work_started() was previously called for the operations.
|
|
ASIO_DECL void abandon_operations(op_queue<operation>& ops);
|
|
|
|
// Get the concurrency hint that was used to initialise the scheduler.
|
|
int concurrency_hint() const
|
|
{
|
|
return concurrency_hint_;
|
|
}
|
|
|
|
private:
|
|
// The mutex type used by this scheduler.
|
|
typedef conditionally_enabled_mutex mutex;
|
|
|
|
// The event type used by this scheduler.
|
|
typedef conditionally_enabled_event event;
|
|
|
|
// Structure containing thread-specific data.
|
|
typedef scheduler_thread_info thread_info;
|
|
|
|
// 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);
|
|
|
|
// Run at most one operation with a timeout. May block.
|
|
ASIO_DECL std::size_t do_wait_one(mutex::scoped_lock& lock,
|
|
thread_info& this_thread, long usec, 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);
|
|
|
|
// 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 run the scheduler in its own thread.
|
|
class thread_function;
|
|
friend class thread_function;
|
|
|
|
// 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_;
|
|
|
|
// Event to wake up blocked threads.
|
|
event wakeup_event_;
|
|
|
|
// 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_;
|
|
|
|
// The concurrency hint used to initialise the scheduler.
|
|
const int concurrency_hint_;
|
|
|
|
// The thread that is running the scheduler.
|
|
asio::detail::thread* thread_;
|
|
};
|
|
|
|
} // namespace detail
|
|
} // namespace asio
|
|
|
|
#include "asio/detail/pop_options.hpp"
|
|
|
|
#if defined(ASIO_HEADER_ONLY)
|
|
# include "asio/detail/impl/scheduler.ipp"
|
|
#endif // defined(ASIO_HEADER_ONLY)
|
|
|
|
#endif // ASIO_DETAIL_SCHEDULER_HPP
|