Imported Upstream version 1.57.0upstream/1.57.0

1 files changed, 180 insertions, 0 deletions

diff --git a/boost/log/detail/locks.hpp b/boost/log/detail/locks.hpp
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+/*
+ *          Copyright Andrey Semashev 2007 - 2014.
+ * 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)
+ */
+/*!
+ * \file   locks.hpp
+ * \author Andrey Semashev
+ * \date   30.05.2010
+ *
+ * \brief  This header is the Boost.Log library implementation, see the library documentation
+ *         at http://www.boost.org/doc/libs/release/libs/log/doc/html/index.html.
+ */
+
+#ifndef BOOST_LOG_DETAIL_LOCKS_HPP_INCLUDED_
+#define BOOST_LOG_DETAIL_LOCKS_HPP_INCLUDED_
+
+#include <boost/log/detail/config.hpp>
+#include <boost/log/detail/header.hpp>
+
+#ifdef BOOST_HAS_PRAGMA_ONCE
+#pragma once
+#endif
+
+namespace boost {
+
+#ifndef BOOST_LOG_NO_THREADS
+
+// Forward declaration of Boost.Thread locks. Specified here to avoid including Boost.Thread,
+// which would bring in many dependent headers, including a great deal of Boost.DateTime.
+template< typename >
+class lock_guard;
+template< typename >
+class shared_lock;
+template< typename >
+class upgrade_lock;
+template< typename >
+class unique_lock;
+
+template< typename >
+struct is_mutex_type;
+
+#endif // BOOST_LOG_NO_THREADS
+
+BOOST_LOG_OPEN_NAMESPACE
+
+//! An auxiliary pseudo-lock to express no locking requirements in logger features
+template< typename MutexT >
+class no_lock
+{
+public:
+    /*!
+     * Constructs the pseudo-lock. The mutex is not affected during the construction.
+     */
+    explicit no_lock(MutexT&) {}
+
+private:
+    no_lock(no_lock const&);
+    no_lock& operator= (no_lock const&);
+};
+
+namespace aux {
+
+#ifndef BOOST_LOG_NO_THREADS
+
+//! A trait to detect if the mutex supports exclusive locking
+template< typename MutexT >
+struct is_exclusively_lockable
+{
+    typedef char true_type;
+    struct false_type { char t[2]; };
+
+    template< typename T >
+    static true_type check_lockable(T*, void (T::*)() = &T::lock, void (T::*)() = &T::unlock);
+    static false_type check_lockable(void*);
+
+    enum value_t { value = sizeof(check_lockable((MutexT*)NULL)) == sizeof(true_type) };
+};
+
+//! A trait to detect if the mutex supports shared locking
+template< typename MutexT >
+struct is_shared_lockable
+{
+    typedef char true_type;
+    struct false_type { char t[2]; };
+
+    template< typename T >
+    static true_type check_shared_lockable(T*, void (T::*)() = &T::lock_shared, void (T::*)() = &T::unlock_shared);
+    static false_type check_shared_lockable(void*);
+
+    enum value_t { value = sizeof(check_shared_lockable((MutexT*)NULL)) == sizeof(true_type) };
+};
+
+//! An analogue to the minimalistic \c lock_guard template. Defined here to avoid including Boost.Thread.
+template< typename MutexT >
+struct exclusive_lock_guard
+{
+    explicit exclusive_lock_guard(MutexT& m) : m_Mutex(m)
+    {
+        m.lock();
+    }
+    ~exclusive_lock_guard()
+    {
+        m_Mutex.unlock();
+    }
+
+private:
+    exclusive_lock_guard(exclusive_lock_guard const&);
+    exclusive_lock_guard& operator= (exclusive_lock_guard const&);
+
+private:
+    MutexT& m_Mutex;
+};
+
+//! An analogue to the minimalistic \c lock_guard template that locks \c shared_mutex with shared ownership.
+template< typename MutexT >
+struct shared_lock_guard
+{
+    explicit shared_lock_guard(MutexT& m) : m_Mutex(m)
+    {
+        m.lock_shared();
+    }
+    ~shared_lock_guard()
+    {
+        m_Mutex.unlock_shared();
+    }
+
+private:
+    shared_lock_guard(shared_lock_guard const&);
+    shared_lock_guard& operator= (shared_lock_guard const&);
+
+private:
+    MutexT& m_Mutex;
+};
+
+//! A deadlock-safe lock type that exclusively locks two mutexes
+template< typename MutexT1, typename MutexT2 >
+class multiple_unique_lock2
+{
+public:
+    multiple_unique_lock2(MutexT1& m1, MutexT2& m2) :
+        m_p1(&m1),
+        m_p2(&m2)
+    {
+        // Yes, it's not conforming, but it works
+        // and it doesn't require to #include <functional>
+        if (static_cast< void* >(m_p1) < static_cast< void* >(m_p2))
+        {
+            m_p1->lock();
+            m_p2->lock();
+        }
+        else
+        {
+            m_p2->lock();
+            m_p1->lock();
+        }
+    }
+    ~multiple_unique_lock2()
+    {
+        m_p2->unlock();
+        m_p1->unlock();
+    }
+
+private:
+    MutexT1* m_p1;
+    MutexT2* m_p2;
+};
+
+#endif // BOOST_LOG_NO_THREADS
+
+} // namespace aux
+
+BOOST_LOG_CLOSE_NAMESPACE // namespace log
+
+} // namespace boost
+
+#include <boost/log/detail/footer.hpp>
+
+#endif // BOOST_LOG_DETAIL_LOCKS_HPP_INCLUDED_