| // |
| // 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 ASIO_DETAIL_SCOPED_LOCK_HPP |
| #define ASIO_DETAIL_SCOPED_LOCK_HPP |
| |
| #if defined(_MSC_VER) && (_MSC_VER >= 1200) |
| # pragma once |
| #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) |
| |
| #include "asio/detail/noncopyable.hpp" |
| |
| #include "asio/detail/push_options.hpp" |
| |
| 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 |
| |
| #include "asio/detail/pop_options.hpp" |
| |
| #endif // ASIO_DETAIL_SCOPED_LOCK_HPP |