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+// -*- C++ -*-
+
+/**
+ * @file ESF_Proxy_RefCount_Guard.h
+ *
+ * $Id$
+ *
+ * @author Carlos O'Ryan (coryan@cs.wustl.edu)
+ *
+ * http://doc.ece.uci.edu/~coryan/EC/index.html
+ */
+
+#ifndef TAO_ESF_PROXY_REFCOUNT_GUARD_H
+#define TAO_ESF_PROXY_REFCOUNT_GUARD_H
+
+#include "tao/Basic_Types.h"
+
+#if !defined (ACE_LACKS_PRAGMA_ONCE)
+# pragma once
+#endif /* ACE_LACKS_PRAGMA_ONCE */
+
+TAO_BEGIN_VERSIONED_NAMESPACE_DECL
+
+/**
+ * @class TAO_ESF_Proxy_RefCount_Guard
+ *
+ * @brief Reference count based guard.
+ *
+ * A common idiom used on event services is to increment a
+ * reference count before starting a long running operation.
+ * The system can then execute the operation without any risk of
+ * having the underlying object destroyed. The advantage of using
+ * a reference count is that no mutex or lock needs to be held
+ * while the operation is beign executed.
+ * This class implements that common idiom, but it also adds hooks
+ * to handle scenarios where more than one operation is performed
+ * while holding the reference count.
+ *
+ * @TODO: The type of lock could be parametric
+ */
+template<class EVENT_CHANNEL, class PROXY>
+class TAO_ESF_Proxy_RefCount_Guard
+{
+public:
+ /// Constructor
+ TAO_ESF_Proxy_RefCount_Guard (CORBA::ULong &refcount,
+ EVENT_CHANNEL *ec,
+ PROXY *proxy);
+
+ /// Destructor
+ ~TAO_ESF_Proxy_RefCount_Guard (void);
+
+protected:
+ /// The reference count, if it gets to zero then the object must be
+ /// destroyed
+ CORBA::ULong &refcount_;
+
+ /// The event channel used to destroy the proxy
+ EVENT_CHANNEL *event_channel_;
+
+ /// The proxy whose lifetime is controlled by the reference count
+ PROXY *proxy_;
+};
+
+TAO_END_VERSIONED_NAMESPACE_DECL
+
+#if defined (__ACE_INLINE__)
+#include "orbsvcs/ESF/ESF_Proxy_RefCount_Guard.inl"
+#endif /* __ACE_INLINE__ */
+
+#if defined (ACE_TEMPLATES_REQUIRE_SOURCE)
+#include "orbsvcs/ESF/ESF_Proxy_RefCount_Guard.cpp"
+#endif /* ACE_TEMPLATES_REQUIRE_SOURCE */
+
+#if defined (ACE_TEMPLATES_REQUIRE_PRAGMA)
+#pragma implementation ("ESF_Proxy_RefCount_Guard.cpp")
+#endif /* ACE_TEMPLATES_REQUIRE_PRAGMA */
+
+#endif /* TAO_ESF_PROXY_REFCOUNT_GUARD_H */