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//
// detail/scoped_lock.hpp
// ~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2016 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 BOOST_ASIO_DETAIL_SCOPED_LOCK_HPP
#define BOOST_ASIO_DETAIL_SCOPED_LOCK_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include <boost/asio/detail/noncopyable.hpp>
#include <boost/asio/detail/push_options.hpp>
namespace boost {
namespace asio {
namespace detail {
// Helper class to lock and unlock a mutex automatically.
template <typename Mutex>
class scoped_lock
: private noncopyable
{
public:
// Tag type used to distinguish constructors.
enum adopt_lock_t { adopt_lock };
// Constructor adopts a lock that is already held.
scoped_lock(Mutex& m, adopt_lock_t)
: mutex_(m),
locked_(true)
{
}
// Constructor acquires the lock.
explicit scoped_lock(Mutex& m)
: mutex_(m)
{
mutex_.lock();
locked_ = true;
}
// Destructor releases the lock.
~scoped_lock()
{
if (locked_)
mutex_.unlock();
}
// Explicitly acquire the lock.
void lock()
{
if (!locked_)
{
mutex_.lock();
locked_ = true;
}
}
// Explicitly release the lock.
void unlock()
{
if (locked_)
{
mutex_.unlock();
locked_ = false;
}
}
// Test whether the lock is held.
bool locked() const
{
return locked_;
}
// Get the underlying mutex.
Mutex& mutex()
{
return mutex_;
}
private:
// The underlying mutex.
Mutex& mutex_;
// Whether the mutex is currently locked or unlocked.
bool locked_;
};
} // namespace detail
} // namespace asio
} // namespace boost
#include <boost/asio/detail/pop_options.hpp>
#endif // BOOST_ASIO_DETAIL_SCOPED_LOCK_HPP
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