comparison DEPENDENCIES/generic/include/boost/log/detail/locking_ptr.hpp @ 16:2665513ce2d3

Add boost headers

+/*
+ *          Copyright Andrey Semashev 2007 - 2013.
+ * 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   locking_ptr.hpp
+ * \author Andrey Semashev
+ * \date   15.07.2009
+ *
+ * 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_LOCKING_PTR_HPP_INCLUDED_
+#define BOOST_LOG_DETAIL_LOCKING_PTR_HPP_INCLUDED_
+
+#include <boost/smart_ptr/shared_ptr.hpp>
+#include <boost/log/detail/config.hpp>
+#include <boost/utility/explicit_operator_bool.hpp>
+#include <boost/log/detail/header.hpp>
+
+#ifdef BOOST_HAS_PRAGMA_ONCE
+#pragma once
+#endif
+
+namespace boost {
+
+BOOST_LOG_OPEN_NAMESPACE
+
+namespace aux {
+
+//! Shared lock object to support locking_ptr
+struct BOOST_LOG_NO_VTABLE locking_ptr_counter_base
+{
+    unsigned int m_RefCounter;
+
+    locking_ptr_counter_base() : m_RefCounter(0)
+    {
+    }
+
+    virtual ~locking_ptr_counter_base() {}
+    virtual void lock() = 0;
+    virtual bool try_lock() = 0;
+    virtual void unlock() = 0;
+
+private:
+    locking_ptr_counter_base(locking_ptr_counter_base const&);
+    locking_ptr_counter_base& operator= (locking_ptr_counter_base const&);
+};
+
+struct try_lock_tag {};
+BOOST_CONSTEXPR_OR_CONST try_lock_tag try_lock = {};
+
+//! A pointer type that locks the backend until it's destroyed
+template< typename T >
+class locking_ptr
+{
+public:
+    //! Pointed type
+    typedef T element_type;
+
+private:
+    //! The pointer to the backend
+    shared_ptr< element_type > m_pElement;
+    //! Reference to the shared lock control object
+    locking_ptr_counter_base* m_pLock;
+
+public:
+    //! Constructor
+    locking_ptr(shared_ptr< element_type > const& p, locking_ptr_counter_base& l)
+        : m_pElement(p), m_pLock(&l)
+    {
+        if (m_pLock->m_RefCounter == 0)
+            m_pLock->lock();
+        ++m_pLock->m_RefCounter;
+    }
+    //! Constructor
+    locking_ptr(shared_ptr< element_type > const& p, locking_ptr_counter_base& l, try_lock_tag const&)
+        : m_pElement(p), m_pLock(&l)
+    {
+        if (m_pLock->m_RefCounter > 0 || m_pLock->try_lock())
+        {
+            ++m_pLock->m_RefCounter;
+        }
+        else
+        {
+            m_pElement.reset();
+            m_pLock = NULL;
+        }
+    }
+    //! Copy constructor
+    locking_ptr(locking_ptr const& that) : m_pElement(that.m_pElement), m_pLock(that.m_pLock)
+    {
+        if (m_pLock)
+            ++m_pLock->m_RefCounter;
+    }
+    //! Destructor
+    ~locking_ptr()
+    {
+        if (m_pLock && --m_pLock->m_RefCounter == 0)
+            m_pLock->unlock();
+    }
+
+    //! Assignment
+    locking_ptr& operator= (locking_ptr that)
+    {
+        this->swap(that);
+        return *this;
+    }
+
+    //! Indirection
+    element_type* operator-> () const { return m_pElement.get(); }
+    //! Dereferencing
+    element_type& operator* () const { return *m_pElement; }
+
+    //! Accessor to the raw pointer
+    element_type* get() const { return m_pElement.get(); }
+
+    //! Checks for null pointer
+    BOOST_EXPLICIT_OPERATOR_BOOL()
+    //! Checks for null pointer
+    bool operator! () const { return !m_pElement; }
+
+    //! Swaps two pointers
+    void swap(locking_ptr& that)
+    {
+        m_pElement.swap(that.m_pElement);
+        register locking_ptr_counter_base* p = m_pLock;
+        m_pLock = that.m_pLock;
+        that.m_pLock = p;
+    }
+};
+
+//! Free raw pointer getter to assist generic programming
+template< typename T >
+inline T* get_pointer(locking_ptr< T > const& p)
+{
+    return p.get();
+}
+//! Free swap operation
+template< typename T >
+inline void swap(locking_ptr< T >& left, locking_ptr< T >& right)
+{
+    left.swap(right);
+}
+
+} // namespace aux
+
+BOOST_LOG_CLOSE_NAMESPACE // namespace log
+
+} // namespace boost
+
+#include <boost/log/detail/footer.hpp>
+
+#endif // BOOST_LOG_DETAIL_LOCKING_PTR_HPP_INCLUDED_