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// -*- C++ -*-
/**
* @file ESF_Copy_On_Write.h
*
* @author Carlos O'Ryan (coryan@cs.wustl.edu)
*
* http://doc.ece.uci.edu/~coryan/EC/index.html
*/
#ifndef TAO_ESF_COPY_ON_WRITE_H
#define TAO_ESF_COPY_ON_WRITE_H
#include "orbsvcs/ESF/ESF_Proxy_Collection.h"
#include "tao/Basic_Types.h"
#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */
TAO_BEGIN_VERSIONED_NAMESPACE_DECL
template<class COLLECTION, class ITERATOR>
class TAO_ESF_Copy_On_Write_Collection
{
public:
TAO_ESF_Copy_On_Write_Collection ();
/// Increment the reference count
CORBA::ULong _incr_refcnt ();
/// Decrement the reference count
CORBA::ULong _decr_refcnt ();
/// The actual collection
COLLECTION collection;
private:
/// The reference count
CORBA::ULong refcount_;
};
// ****************************************************************
/**
* @class TAO_ESF_Copy_On_Write_Read_Guard
*
* @brief TAO_ESF_Copy_On_Write_Read_Guard
*
* This helper class atomically increments the reference count of
* a TAO_ESF_Copy_On_Write_Collection and reads the current
* collection in the Copy_On_Write class.
*/
template<class COLLECTION, class ITERATOR, class ACE_LOCK>
class TAO_ESF_Copy_On_Write_Read_Guard
{
public:
/// Constructor
typedef TAO_ESF_Copy_On_Write_Collection<COLLECTION,ITERATOR> Collection;
TAO_ESF_Copy_On_Write_Read_Guard (ACE_LOCK &mutex,
Collection *&collection);
/// Destructor
~TAO_ESF_Copy_On_Write_Read_Guard ();
Collection *collection;
private:
ACE_LOCK &mutex;
};
// ****************************************************************
/**
* @class TAO_ESF_Copy_On_Write_Write_Guard
*
* @brief TAO_ESF_Copy_On_Write_Write_Guard
*
* This helper class atomically increments the reference count of
* a TAO_ESF_Copy_On_Write_Collection and reads the current
* collection in the Copy_On_Write class.
*/
template<class COLLECTION, class ITERATOR, ACE_SYNCH_DECL>
class TAO_ESF_Copy_On_Write_Write_Guard
{
public:
/// Constructor
typedef TAO_ESF_Copy_On_Write_Collection<COLLECTION,ITERATOR> Collection;
TAO_ESF_Copy_On_Write_Write_Guard (ACE_SYNCH_MUTEX_T &mutex,
ACE_SYNCH_CONDITION_T &cond,
int &pending_writes,
int &writing_flag,
Collection*& collection);
/// Destructor
~TAO_ESF_Copy_On_Write_Write_Guard ();
Collection *copy;
private:
ACE_SYNCH_MUTEX_T &mutex;
ACE_SYNCH_CONDITION_T &cond;
int &pending_writes;
int &writing_flag;
Collection *&collection;
};
// ****************************************************************
/**
* @class TAO_ESF_Copy_On_Write
*
* @brief TAO_ESF_Copy_On_Write
*
* Implement the Copy_On_Write protocol
* The class is parametric on the kind of collection and locking
* mechanism used.
*/
template<class PROXY, class COLLECTION, class ITERATOR, ACE_SYNCH_DECL>
class TAO_ESF_Copy_On_Write : public TAO_ESF_Proxy_Collection<PROXY>
{
public:
/// Constructor
typedef TAO_ESF_Copy_On_Write_Read_Guard<COLLECTION,ITERATOR,ACE_SYNCH_MUTEX_T> Read_Guard;
typedef TAO_ESF_Copy_On_Write_Write_Guard<COLLECTION,ITERATOR,ACE_SYNCH_USE> Write_Guard;
TAO_ESF_Copy_On_Write ();
/// Destructor
~TAO_ESF_Copy_On_Write ();
// = The TAO_ESF_Proxy methods
virtual void for_each (TAO_ESF_Worker<PROXY> *worker);
virtual void connected (PROXY *proxy);
virtual void reconnected (PROXY *proxy);
virtual void disconnected (PROXY *proxy);
virtual void shutdown ();
private:
typedef TAO_ESF_Copy_On_Write_Collection<COLLECTION,ITERATOR> Collection;
/// A mutex to serialize access to the collection pointer.
ACE_SYNCH_MUTEX_T mutex_;
/// Number of pending writes
int pending_writes_;
/**
* If non-zero then a thread is changing the collection. Many
* threads can use the collection simulatenously, but only one
* change it.
*/
int writing_;
/// A condition variable to wait to synchronize multiple writers.
ACE_SYNCH_CONDITION_T cond_;
/// The collection, with reference counting added
Collection *collection_;
};
// ****************************************************************
TAO_END_VERSIONED_NAMESPACE_DECL
#if defined (__ACE_INLINE__)
#include "orbsvcs/ESF/ESF_Copy_On_Write.inl"
#endif /* __ACE_INLINE__ */
#if defined (ACE_TEMPLATES_REQUIRE_SOURCE)
#include "orbsvcs/ESF/ESF_Copy_On_Write.cpp"
#endif /* ACE_TEMPLATES_REQUIRE_SOURCE */
#if defined (ACE_TEMPLATES_REQUIRE_PRAGMA)
#pragma implementation ("ESF_Copy_On_Write.cpp")
#endif /* ACE_TEMPLATES_REQUIRE_PRAGMA */
#endif /* TAO_ESF_COPY_ON_WRITE_H */
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