Added boost header

test/external/boost/interprocess/smart_ptr/weak_ptr.hpp

@@ -0,0 +1,259 @@
+//////////////////////////////////////////////////////////////////////////////
+//
+// This file is the adaptation for Interprocess of boost/weak_ptr.hpp
+//
+// (C) Copyright Peter Dimov 2001, 2002, 2003
+// (C) Copyright Ion Gaztanaga 2006-2009.
+// 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)
+//
+// See http://www.boost.org/libs/interprocess for documentation.
+//
+//////////////////////////////////////////////////////////////////////////////
+
+#ifndef BOOST_INTERPROCESS_WEAK_PTR_HPP_INCLUDED
+#define BOOST_INTERPROCESS_WEAK_PTR_HPP_INCLUDED
+
+#include <boost/interprocess/detail/config_begin.hpp>
+#include <boost/interprocess/detail/workaround.hpp>
+
+#include <boost/interprocess/smart_ptr/shared_ptr.hpp>
+#include <boost/detail/no_exceptions_support.hpp>
+#include <boost/interprocess/allocators/allocator.hpp>
+#include <boost/interprocess/smart_ptr/deleter.hpp>
+#include <boost/pointer_to_other.hpp>
+
+//!\file
+//!Describes the smart pointer weak_ptr.
+
+namespace boost{
+namespace interprocess{
+
+//!The weak_ptr class template stores a "weak reference" to an object
+//!that's already managed by a shared_ptr. To access the object, a weak_ptr 
+//!can be converted to a shared_ptr using  the shared_ptr constructor or the
+//!member function  lock. When the last shared_ptr to the object goes away
+//!and the object is deleted, the attempt to obtain a shared_ptr from the
+//!weak_ptr instances that refer to the deleted object will fail: the constructor
+//!will throw an exception of type bad_weak_ptr, and weak_ptr::lock will
+//!return an empty shared_ptr.
+//!
+//!Every weak_ptr meets the CopyConstructible and Assignable requirements
+//!of the C++ Standard Library, and so can be used in standard library containers.
+//!Comparison operators are supplied so that weak_ptr works with the standard
+//!library's associative containers.
+//!
+//!weak_ptr operations never throw exceptions.
+//!
+//!The class template is parameterized on T, the type of the object pointed to.
+template<class T, class A, class D>
+class weak_ptr
+{
+   /// @cond
+   private:
+   // Borland 5.5.1 specific workarounds
+   typedef weak_ptr<T, A, D> this_type;
+   typedef typename boost::pointer_to_other
+      <typename A::pointer, T>::type      pointer;
+   typedef typename ipcdetail::add_reference
+                     <T>::type            reference;
+   typedef typename ipcdetail::add_reference
+                     <T>::type            const_reference;
+   /// @endcond
+
+   public:
+   typedef T element_type;
+   typedef T value_type;
+
+   //!Effects: Constructs an empty weak_ptr.
+   //!Postconditions: use_count() == 0.
+   weak_ptr()
+   : m_pn() // never throws
+   {}
+   //  generated copy constructor, assignment, destructor are fine
+   //
+   //  The "obvious" converting constructor implementation:
+   //
+   //  template<class Y>
+   //  weak_ptr(weak_ptr<Y> const & r): m_px(r.m_px), m_pn(r.m_pn) // never throws
+   //  {
+   //  }
+   //
+   //  has a serious problem.
+   //
+   //  r.m_px may already have been invalidated. The m_px(r.m_px)
+   //  conversion may require access to *r.m_px (virtual inheritance).
+   //
+   //  It is not possible to avoid spurious access violations since
+   //  in multithreaded programs r.m_px may be invalidated at any point.
+
+   //!Effects: If r is empty, constructs an empty weak_ptr; otherwise,
+   //!constructs a weak_ptr that shares ownership with r as if by storing a
+   //!copy of the pointer stored in r.
+   //!
+   //!Postconditions: use_count() == r.use_count().
+   //!
+   //!Throws: nothing.
+   template<class Y>
+   weak_ptr(weak_ptr<Y, A, D> const & r)
+      : m_pn(r.m_pn) // never throws
+   {  
+      //Construct a temporary shared_ptr so that nobody
+      //can destroy the value while constructing this
+      const shared_ptr<T, A, D> &ref = r.lock();
+      m_pn.set_pointer(ref.get()); 
+   }
+
+   //!Effects: If r is empty, constructs an empty weak_ptr; otherwise,
+   //!constructs a weak_ptr that shares ownership with r as if by storing a
+   //!copy of the pointer stored in r.
+   //!
+   //!Postconditions: use_count() == r.use_count().
+   //!
+   //!Throws: nothing.
+   template<class Y>
+   weak_ptr(shared_ptr<Y, A, D> const & r)
+      : m_pn(r.m_pn) // never throws
+   {}
+
+   //!Effects: Equivalent to weak_ptr(r).swap(*this).
+   //!
+   //!Throws: nothing.
+   //!
+   //!Notes: The implementation is free to meet the effects (and the
+   //!implied guarantees) via different means, without creating a temporary.
+   template<class Y>
+   weak_ptr & operator=(weak_ptr<Y, A, D> const & r) // never throws
+   {  
+      //Construct a temporary shared_ptr so that nobody
+      //can destroy the value while constructing this
+      const shared_ptr<T, A, D> &ref = r.lock();
+      m_pn = r.m_pn;
+      m_pn.set_pointer(ref.get());
+      return *this;
+   }
+
+   //!Effects: Equivalent to weak_ptr(r).swap(*this).
+   //!
+   //!Throws: nothing.
+   //!
+   //!Notes: The implementation is free to meet the effects (and the
+   //!implied guarantees) via different means, without creating a temporary.
+   template<class Y>
+   weak_ptr & operator=(shared_ptr<Y, A, D> const & r) // never throws
+   {  m_pn = r.m_pn;  return *this;  }
+
+   //!Returns: expired()? shared_ptr<T>(): shared_ptr<T>(*this).
+   //!
+   //!Throws: nothing.
+   shared_ptr<T, A, D> lock() const // never throws
+   {
+      // optimization: avoid throw overhead
+      if(expired()){
+         return shared_ptr<element_type, A, D>();
+      }
+      BOOST_TRY{
+         return shared_ptr<element_type, A, D>(*this);
+      }
+      BOOST_CATCH(bad_weak_ptr const &){
+         // Q: how can we get here?
+         // A: another thread may have invalidated r after the use_count test above.
+         return shared_ptr<element_type, A, D>();
+      }
+      BOOST_CATCH_END
+   }
+
+   //!Returns: 0 if *this is empty; otherwise, the number of shared_ptr objects
+   //!that share ownership with *this.
+   //!
+   //!Throws: nothing.
+   //!
+   //!Notes: use_count() is not necessarily efficient. Use only for debugging and
+   //!testing purposes, not for production code.
+   long use_count() const // never throws
+   {  return m_pn.use_count();  }
+    
+   //!Returns: Returns: use_count() == 0.
+   //!
+   //!Throws: nothing.
+   //!
+   //!Notes: expired() may be faster than use_count().
+   bool expired() const // never throws
+   {  return m_pn.use_count() == 0;   }
+
+   //!Effects: Equivalent to:
+   //!weak_ptr().swap(*this).
+   void reset() // never throws in 1.30+
+   {  this_type().swap(*this);   }
+
+   //!Effects: Exchanges the contents of the two
+   //!smart pointers.
+   //!
+   //!Throws: nothing.
+   void swap(this_type & other) // never throws
+   {  ipcdetail::do_swap(m_pn, other.m_pn);   }
+
+   /// @cond
+   template<class T2, class A2, class D2> 
+   bool _internal_less(weak_ptr<T2, A2, D2> const & rhs) const
+   {  return m_pn < rhs.m_pn;  }
+   
+   template<class Y>
+   void _internal_assign(const ipcdetail::shared_count<Y, A, D> & pn2)
+   {
+
+      m_pn = pn2;
+   }
+
+   private:
+
+   template<class T2, class A2, class D2> friend class shared_ptr;
+   template<class T2, class A2, class D2> friend class weak_ptr;
+
+   ipcdetail::weak_count<T, A, D> m_pn;      // reference counter
+   /// @endcond
+};  // weak_ptr
+
+template<class T, class A, class D, class U, class A2, class D2> inline 
+bool operator<(weak_ptr<T, A, D> const & a, weak_ptr<U, A2, D2> const & b)
+{  return a._internal_less(b);   }
+
+template<class T, class A, class D> inline
+void swap(weak_ptr<T, A, D> & a, weak_ptr<T, A, D> & b)
+{  a.swap(b);  }
+
+//!Returns the type of a weak pointer
+//!of type T with the allocator boost::interprocess::allocator allocator
+//!and boost::interprocess::deleter deleter
+//!that can be constructed in the given managed segment type.
+template<class T, class ManagedMemory>
+struct managed_weak_ptr
+{
+   typedef weak_ptr
+   < T
+   , typename ManagedMemory::template allocator<void>::type
+   , typename ManagedMemory::template deleter<T>::type
+   > type;
+};
+
+//!Returns an instance of a weak pointer constructed
+//!with the default allocator and deleter from a pointer
+//!of type T that has been allocated in the passed managed segment
+template<class T, class ManagedMemory>
+inline typename managed_weak_ptr<T, ManagedMemory>::type
+   make_managed_weak_ptr(T *constructed_object, ManagedMemory &managed_memory)
+{
+   return typename managed_weak_ptr<T, ManagedMemory>::type
+   ( constructed_object
+   , managed_memory.template get_allocator<void>()
+   , managed_memory.template get_deleter<T>()
+   );
+}
+
+} // namespace interprocess
+} // namespace boost
+
+#include <boost/interprocess/detail/config_end.hpp>
+
+#endif  // #ifndef BOOST_INTERPROCESS_WEAK_PTR_HPP_INCLUDED