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//
// executor_work_guard.hpp
// ~~~~~~~~~~~~~~~~~
//
// 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_EXECUTOR_WORK_GUARD_HPP
#define ASIO_EXECUTOR_WORK_GUARD_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include "asio/detail/config.hpp"
#include "asio/associated_executor.hpp"
#include "asio/detail/type_traits.hpp"
#include "asio/is_executor.hpp"
#include "asio/detail/push_options.hpp"
namespace asio {
/// An object of type @c executor_work_guard controls ownership of executor work
/// within a scope.
template <typename Executor>
class executor_work_guard
{
public:
/// The underlying executor type.
typedef Executor executor_type;
/// Constructs a @c executor_work_guard object for the specified executor.
/**
* Stores a copy of @c e and calls <tt>on_work_started()</tt> on it.
*/
explicit executor_work_guard(const executor_type& e) ASIO_NOEXCEPT
: executor_(e),
owns_(true)
{
executor_.on_work_started();
}
/// Copy constructor.
executor_work_guard(const executor_work_guard& other) ASIO_NOEXCEPT
: executor_(other.executor_),
owns_(other.owns_)
{
if (owns_)
executor_.on_work_started();
}
#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
/// Move constructor.
executor_work_guard(executor_work_guard&& other)
: executor_(ASIO_MOVE_CAST(Executor)(other.executor_)),
owns_(other.owns_)
{
other.owns_ = false;
}
#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
/// Destructor.
/**
* Unless the object has already been reset, or is in a moved-from state,
* calls <tt>on_work_finished()</tt> on the stored executor.
*/
~executor_work_guard()
{
if (owns_)
executor_.on_work_finished();
}
/// Obtain the associated executor.
executor_type get_executor() const ASIO_NOEXCEPT
{
return executor_;
}
/// Whether the executor_work_guard object owns some outstanding work.
bool owns_work() const ASIO_NOEXCEPT
{
return owns_;
}
/// Indicate that the work is no longer outstanding.
/*
* Unless the object has already been reset, or is in a moved-from state,
* calls <tt>on_work_finished()</tt> on the stored executor.
*/
void reset() ASIO_NOEXCEPT
{
if (owns_)
{
executor_.on_work_finished();
owns_ = false;
}
}
private:
// Disallow assignment.
executor_work_guard& operator=(const executor_work_guard&);
executor_type executor_;
bool owns_;
};
/// Create an @ref executor_work_guard object.
template <typename Executor>
inline executor_work_guard<Executor> make_work_guard(const Executor& ex,
typename enable_if<is_executor<Executor>::value>::type* = 0)
{
return executor_work_guard<Executor>(ex);
}
/// Create an @ref executor_work_guard object.
template <typename ExecutionContext>
inline executor_work_guard<typename ExecutionContext::executor_type>
make_work_guard(ExecutionContext& ctx,
typename enable_if<
is_convertible<ExecutionContext&, execution_context&>::value>::type* = 0)
{
return executor_work_guard<typename ExecutionContext::executor_type>(
ctx.get_executor());
}
/// Create an @ref executor_work_guard object.
template <typename T>
inline executor_work_guard<typename associated_executor<T>::type>
make_work_guard(const T& t,
typename enable_if<!is_executor<T>::value &&
!is_convertible<T&, execution_context&>::value>::type* = 0)
{
return executor_work_guard<typename associated_executor<T>::type>(
associated_executor<T>::get(t));
}
/// Create an @ref executor_work_guard object.
template <typename T, typename Executor>
inline executor_work_guard<typename associated_executor<T, Executor>::type>
make_work_guard(const T& t, const Executor& ex,
typename enable_if<is_executor<Executor>::value>::type* = 0)
{
return executor_work_guard<typename associated_executor<T, Executor>::type>(
associated_executor<T, Executor>::get(t, ex));
}
/// Create an @ref executor_work_guard object.
template <typename T, typename ExecutionContext>
inline executor_work_guard<typename associated_executor<T,
typename ExecutionContext::executor_type>::type>
make_work_guard(const T& t, ExecutionContext& ctx,
typename enable_if<!is_executor<T>::value &&
!is_convertible<T&, execution_context&>::value &&
is_convertible<ExecutionContext&, execution_context&>::value>::type* = 0)
{
return executor_work_guard<typename associated_executor<T,
typename ExecutionContext::executor_type>::type>(
associated_executor<T, typename ExecutionContext::executor_type>::get(
t, ctx.get_executor()));
}
} // namespace asio
#include "asio/detail/pop_options.hpp"
#endif // ASIO_EXECUTOR_WORK_GUARD_HPP
|
