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// -*- C++ -*-
//=============================================================================
/**
* @file Refcounted_Auto_Ptr.h
*
* $Id$
*
* @author John Tucker <JTucker@infoglide.com>
*/
//=============================================================================
#ifndef ACE_REFCOUNTED_AUTO_PTR_H
#define ACE_REFCOUNTED_AUTO_PTR_H
#include /**/ "ace/pre.h"
#include "ace/Auto_Ptr.h"
#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */
ACE_BEGIN_VERSIONED_NAMESPACE_DECL
// Forward decl.
template <class X, class ACE_LOCK> class ACE_Refcounted_Auto_Ptr_Rep;
template <class X, class ACE_LOCK> class ACE_Refcounted_Auto_Ptr;
/**
* @class ACE_Refcounted_Auto_Ptr
*
* @brief This class implements support for a reference counted auto_ptr.
* Assigning or copying instances of an ACE_Refcounted_Auto_Ptr
* will automatically increment the reference count. When the last
* instance that references a ACE_Refcounted_Auto_Ptr instance is
* destroyed or overwritten, it will invoke delete on its underlying
* pointer.
*
* The ACE_Refcounted_Auto_Ptr works by maintaining a reference to a
* separate representation object, ACE_Refcounted_Auto_Ptr_Rep. That
* separate representation object contains the reference count and
* the actual pointer value.
*/
template <class X, class ACE_LOCK>
class ACE_Refcounted_Auto_Ptr
{
public:
// = Initialization and termination methods.
/// Constructor that initializes an ACE_Refcounted_Auto_Ptr to
/// the specified pointer value.
ACE_Refcounted_Auto_Ptr (X *p = 0);
/// Copy constructor binds the new ACE_Refcounted_Auto_Ptr to the
/// representation object referenced by @a r.
/// An ACE_Refcounted_Auto_Ptr_Rep is created if necessary.
ACE_Refcounted_Auto_Ptr (const ACE_Refcounted_Auto_Ptr<X, ACE_LOCK> &r);
/// Destructor. Releases the reference to the underlying representation.
/// If the release of that reference causes its reference count to reach 0,
/// the representation object will also be destroyed.
virtual ~ACE_Refcounted_Auto_Ptr (void);
/// Assignment operator that binds the current object and @a r to the same
/// ACE_Refcounted_Auto_Ptr_Rep. An ACE_Refcounted_Auto_Ptr_Rep
/// is created if necessary.
void operator = (const ACE_Refcounted_Auto_Ptr<X, ACE_LOCK> &r);
/// Equality operator that returns @c true if both
/// ACE_Refcounted_Auto_Ptr objects point to the same underlying
/// representation. It does not compare the actual pointers.
/**
* @note It also returns @c true if both objects have just been
* instantiated and not used yet.
*/
bool operator == (const ACE_Refcounted_Auto_Ptr<X, ACE_LOCK> &r) const;
/// Inequality operator, which is the opposite of equality.
bool operator != (const ACE_Refcounted_Auto_Ptr<X, ACE_LOCK> &r) const;
/// Redirection operator
X *operator-> (void) const;
/// Accessor method.
X &operator *() const;
/// Releases the reference to the underlying representation object.
/// @retval The pointer value prior to releasing it.
X *release (void);
/// Releases the current pointer value and then sets a new
/// pointer value specified by @a p.
void reset (X *p = 0);
/// Get the pointer value.
X *get (void) const;
/// Get the reference count value.
int count (void) const;
/// Returns @c true if this object does not contain a valid pointer.
bool null (void) const;
/// Declare the dynamic allocation hooks.
ACE_ALLOC_HOOK_DECLARE;
protected:
/// the ACE_Refcounted_Auto_Ptr_Rep
typedef ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> AUTO_REFCOUNTED_PTR_REP;
/// Protect operations on the ACE_Refcounted_Auto_Ptr.
AUTO_REFCOUNTED_PTR_REP *rep_;
};
/**
* @class ACE_Refcounted_Auto_Ptr_Rep
*
* @brief An ACE_Refcounted_Auto_Ptr_Rep object encapsulates a pointer
* to an object of type X. It uses a lock object of type ACE_LOCK to protect
* access to the reference count.
*
* @internal ACE_Refcounted_Auto_Ptr_Rep is used internally by the
* ACE_Refcounted_Auto_Ptr class and is only accessible through it.
*/
template <class X, class ACE_LOCK>
class ACE_Refcounted_Auto_Ptr_Rep
{
private:
friend class ACE_Refcounted_Auto_Ptr<X, ACE_LOCK>;
/// Get the pointer value.
X *get (void) const;
/// Get the reference count value.
int count (void) const;
/// Declare the dynamic allocation hooks.
ACE_ALLOC_HOOK_DECLARE;
// = Encapsulate reference count and object lifetime of instances.
// These methods must go after the others to work around a bug with
// Borland's C++ Builder...
/// Allocate a new ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> instance,
/// returning NULL if it cannot be created.
static ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> *internal_create (X *p);
/// Create a ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> and initialize
/// the reference count.
static ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> *create (X *p);
/// Increase the reference count on @a rep.
///
/// @retval @a rep if success, 0 if there's an error obtaining the lock
/// on @a rep.
static ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> *attach (ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> *&rep);
/// Decreases the reference count and and deletes rep if there are no
/// more references to rep.
///
/// Precondition (rep != 0)
static void detach (ACE_Refcounted_Auto_Ptr_Rep<X, ACE_LOCK> *&rep);
/// Pointer to the result.
ACE_Auto_Basic_Ptr<X> ptr_;
/// Reference count.
int ref_count_;
// = Mutex variable to protect the <ptr_>.
/// Synchronization variable for serializing access to ref_count_
mutable ACE_LOCK lock_;
private:
// = Constructor and destructor private.
ACE_Refcounted_Auto_Ptr_Rep (X *p = 0);
~ACE_Refcounted_Auto_Ptr_Rep (void);
};
ACE_END_VERSIONED_NAMESPACE_DECL
#include "ace/Refcounted_Auto_Ptr.inl"
#if defined (ACE_TEMPLATES_REQUIRE_SOURCE)
#include "ace/Refcounted_Auto_Ptr.cpp"
#endif /* ACE_TEMPLATES_REQUIRE_SOURCE */
#if defined (ACE_TEMPLATES_REQUIRE_PRAGMA)
#pragma implementation ("Refcounted_Auto_Ptr.cpp")
#endif /* ACE_TEMPLATES_REQUIRE_PRAGMA */
#include /**/ "ace/post.h"
#endif /* ACE_REFCOUNTED_AUTO_PTR_H */
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