Chris@16: //
Chris@16: // detail/scoped_lock.hpp
Chris@16: // ~~~~~~~~~~~~~~~~~~~~~~
Chris@16: //
Chris@101: // Copyright (c) 2003-2015 Christopher M. Kohlhoff (chris at kohlhoff dot com)
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16: // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: 
Chris@16: #ifndef BOOST_ASIO_DETAIL_SCOPED_LOCK_HPP
Chris@16: #define BOOST_ASIO_DETAIL_SCOPED_LOCK_HPP
Chris@16: 
Chris@16: #if defined(_MSC_VER) && (_MSC_VER >= 1200)
Chris@16: # pragma once
Chris@16: #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
Chris@16: 
Chris@16: #include <boost/asio/detail/noncopyable.hpp>
Chris@16: 
Chris@16: #include <boost/asio/detail/push_options.hpp>
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace asio {
Chris@16: namespace detail {
Chris@16: 
Chris@16: // Helper class to lock and unlock a mutex automatically.
Chris@16: template <typename Mutex>
Chris@16: class scoped_lock
Chris@16:   : private noncopyable
Chris@16: {
Chris@16: public:
Chris@16:   // Tag type used to distinguish constructors.
Chris@16:   enum adopt_lock_t { adopt_lock };
Chris@16: 
Chris@16:   // Constructor adopts a lock that is already held.
Chris@16:   scoped_lock(Mutex& m, adopt_lock_t)
Chris@16:     : mutex_(m),
Chris@16:       locked_(true)
Chris@16:   {
Chris@16:   }
Chris@16: 
Chris@16:   // Constructor acquires the lock.
Chris@16:   explicit scoped_lock(Mutex& m)
Chris@16:     : mutex_(m)
Chris@16:   {
Chris@16:     mutex_.lock();
Chris@16:     locked_ = true;
Chris@16:   }
Chris@16: 
Chris@16:   // Destructor releases the lock.
Chris@16:   ~scoped_lock()
Chris@16:   {
Chris@16:     if (locked_)
Chris@16:       mutex_.unlock();
Chris@16:   }
Chris@16: 
Chris@16:   // Explicitly acquire the lock.
Chris@16:   void lock()
Chris@16:   {
Chris@16:     if (!locked_)
Chris@16:     {
Chris@16:       mutex_.lock();
Chris@16:       locked_ = true;
Chris@16:     }
Chris@16:   }
Chris@16: 
Chris@16:   // Explicitly release the lock.
Chris@16:   void unlock()
Chris@16:   {
Chris@16:     if (locked_)
Chris@16:     {
Chris@16:       mutex_.unlock();
Chris@16:       locked_ = false;
Chris@16:     }
Chris@16:   }
Chris@16: 
Chris@16:   // Test whether the lock is held.
Chris@16:   bool locked() const
Chris@16:   {
Chris@16:     return locked_;
Chris@16:   }
Chris@16: 
Chris@16:   // Get the underlying mutex.
Chris@16:   Mutex& mutex()
Chris@16:   {
Chris@16:     return mutex_;
Chris@16:   }
Chris@16: 
Chris@16: private:
Chris@16:   // The underlying mutex.
Chris@16:   Mutex& mutex_;
Chris@16: 
Chris@16:   // Whether the mutex is currently locked or unlocked.
Chris@16:   bool locked_;
Chris@16: };
Chris@16: 
Chris@16: } // namespace detail
Chris@16: } // namespace asio
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #include <boost/asio/detail/pop_options.hpp>
Chris@16: 
Chris@16: #endif // BOOST_ASIO_DETAIL_SCOPED_LOCK_HPP