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For more information * on the Apache Software Foundation, please see * <http://www.apache.org/>. */ /* * $Id: XMLRegisterCleanup.hpp,v 1.2 2002/11/04 15:22:05 tng Exp $ * $Log: XMLRegisterCleanup.hpp,v $ * Revision 1.2 2002/11/04 15:22:05 tng * C++ Namespace Support. * * Revision 1.1.1.1 2002/02/01 22:22:15 peiyongz * sane_include * * Revision 1.4 2001/10/25 21:55:29 peiyongz * copy ctor explicity declared private to prevent supprise. * * Revision 1.3 2001/10/24 18:13:06 peiyongz * CVS tag added * * */ #if !defined(XMLREGISTERCLEANUP_HPP) #define XMLREGISTERCLEANUP_HPP #include <xercesc/util/Mutexes.hpp> XERCES_CPP_NAMESPACE_BEGIN // This is a mutex for exclusive use by this class extern XMLMutex* gXMLCleanupListMutex; // This is the head of a list of XMLRegisterCleanup objects that // is used during XMLPlatformUtils::Terminate() to find objects to // clean up class XMLRegisterCleanup; extern XMLRegisterCleanup* gXMLCleanupList; // // For internal use only. // // This class is used by the platform utilities class to support // reinitialisation of global/static data which is lazily created. // Since that data is widely spread out the platform utilities // class cannot know about them directly. So, the code that creates such // objects creates an registers a cleanup for the object. The platform // termination call will iterate the list and delete the objects. // // N.B. These objects need to be statically allocated. I couldn't think // of a neat way of ensuring this - can anyone else? class XMLRegisterCleanup { public : // The cleanup function to be called on XMLPlatformUtils::Terminate() typedef void (*XMLCleanupFn)(); void doCleanup() { // When performing cleanup, we only do this once, but we can // cope if somehow we have been called twice. if (m_cleanupFn) m_cleanupFn(); // We need to remove "this" from the list // irregardless of the cleanup Function unregisterCleanup(); } // This function is called during initialisation of static data to // register a function to be called on XMLPlatformUtils::Terminate. // It gives an object that uses static data an opportunity to reset // such data. void registerCleanup(XMLCleanupFn cleanupFn) { // Store the cleanup function m_cleanupFn = cleanupFn; // Add this object to the list head, if it is not already // present - which it shouldn't be. // This is done under a mutex to ensure thread safety. gXMLCleanupListMutex->lock(); if (!m_nextCleanup && !m_prevCleanup) { m_nextCleanup = gXMLCleanupList; gXMLCleanupList = this; if (m_nextCleanup) m_nextCleanup->m_prevCleanup = this; } gXMLCleanupListMutex->unlock(); } // This function can be called either from XMLPlatformUtils::Terminate // to state that the cleanup has been performed and should not be // performed again, or from code that you have written that determines // that cleanup is no longer necessary. void unregisterCleanup() { gXMLCleanupListMutex->lock(); // // To protect against some compiler's (eg hp11) optimization // to change "this" as they update gXMLCleanupList // // refer to // void XMLPlatformUtils::Terminate() // ... // while (gXMLCleanupList) // gXMLCleanupList->doCleanup(); // XMLRegisterCleanup *tmpThis = (XMLRegisterCleanup*) this; // Unlink this object from the cleanup list if (m_nextCleanup) m_nextCleanup->m_prevCleanup = m_prevCleanup; if (!m_prevCleanup) gXMLCleanupList = m_nextCleanup; else m_prevCleanup->m_nextCleanup = m_nextCleanup; gXMLCleanupListMutex->unlock(); // Reset the object to the default state tmpThis->resetCleanup(); } // The default constructor sets a state that ensures that this object // will do nothing XMLRegisterCleanup() { resetCleanup(); } private: // // unsupported ctor and operator // XMLRegisterCleanup(const XMLRegisterCleanup&) {} // This is the cleanup function to be called XMLCleanupFn m_cleanupFn; // These are list pointers to the next/prev cleanup function to be called XMLRegisterCleanup *m_nextCleanup, *m_prevCleanup; // This function reinitialises the object to the default state void resetCleanup() { m_nextCleanup = 0; m_prevCleanup = 0; m_cleanupFn = 0; } }; XERCES_CPP_NAMESPACE_END #endif

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