00001 // -*- C++ -*- 00002 00003 /** 00004 * @file ESF_Proxy_RefCount_Guard.h 00005 * 00006 * ESF_Proxy_RefCount_Guard.h,v 1.7 2006/03/15 07:52:21 jtc Exp 00007 * 00008 * @author Carlos O'Ryan (coryan@cs.wustl.edu) 00009 * 00010 * http://doc.ece.uci.edu/~coryan/EC/index.html 00011 */ 00012 00013 #ifndef TAO_ESF_PROXY_REFCOUNT_GUARD_H 00014 #define TAO_ESF_PROXY_REFCOUNT_GUARD_H 00015 00016 #include "tao/Basic_Types.h" 00017 00018 #if !defined (ACE_LACKS_PRAGMA_ONCE) 00019 # pragma once 00020 #endif /* ACE_LACKS_PRAGMA_ONCE */ 00021 00022 TAO_BEGIN_VERSIONED_NAMESPACE_DECL 00023 00024 /** 00025 * @class TAO_ESF_Proxy_RefCount_Guard 00026 * 00027 * @brief Reference count based guard. 00028 * 00029 * A common idiom used on event services is to increment a 00030 * reference count before starting a long running operation. 00031 * The system can then execute the operation without any risk of 00032 * having the underlying object destroyed. The advantage of using 00033 * a reference count is that no mutex or lock needs to be held 00034 * while the operation is beign executed. 00035 * This class implements that common idiom, but it also adds hooks 00036 * to handle scenarios where more than one operation is performed 00037 * while holding the reference count. 00038 * 00039 * @TODO: The type of lock could be parametric 00040 */ 00041 template<class EVENT_CHANNEL, class PROXY> 00042 class TAO_ESF_Proxy_RefCount_Guard 00043 { 00044 public: 00045 /// Constructor 00046 TAO_ESF_Proxy_RefCount_Guard (CORBA::ULong &refcount, 00047 EVENT_CHANNEL *ec, 00048 PROXY *proxy); 00049 00050 /// Destructor 00051 ~TAO_ESF_Proxy_RefCount_Guard (void); 00052 00053 protected: 00054 /// The reference count, if it gets to zero then the object must be 00055 /// destroyed 00056 CORBA::ULong &refcount_; 00057 00058 /// The event channel used to destroy the proxy 00059 EVENT_CHANNEL *event_channel_; 00060 00061 /// The proxy whose lifetime is controlled by the reference count 00062 PROXY *proxy_; 00063 }; 00064 00065 TAO_END_VERSIONED_NAMESPACE_DECL 00066 00067 #if defined (__ACE_INLINE__) 00068 #include "orbsvcs/ESF/ESF_Proxy_RefCount_Guard.i" 00069 #endif /* __ACE_INLINE__ */ 00070 00071 #if defined (ACE_TEMPLATES_REQUIRE_SOURCE) 00072 #include "orbsvcs/ESF/ESF_Proxy_RefCount_Guard.cpp" 00073 #endif /* ACE_TEMPLATES_REQUIRE_SOURCE */ 00074 00075 #if defined (ACE_TEMPLATES_REQUIRE_PRAGMA) 00076 #pragma implementation ("ESF_Proxy_RefCount_Guard.cpp") 00077 #endif /* ACE_TEMPLATES_REQUIRE_PRAGMA */ 00078 00079 #endif /* TAO_ESF_PROXY_REFCOUNT_GUARD_H */
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