00001 /*
00002 * The Apache Software License, Version 1.1
00003 *
00004 * Copyright (c) 1999-2000 The Apache Software Foundation. All rights
00005 * reserved.
00006 *
00007 * Redistribution and use in source and binary forms, with or without
00008 * modification, are permitted provided that the following conditions
00009 * are met:
00010 *
00011 * 1. Redistributions of source code must retain the above copyright
00012 * notice, this list of conditions and the following disclaimer.
00013 *
00014 * 2. Redistributions in binary form must reproduce the above copyright
00015 * notice, this list of conditions and the following disclaimer in
00016 * the documentation and/or other materials provided with the
00017 * distribution.
00018 *
00019 * 3. The end-user documentation included with the redistribution,
00020 * if any, must include the following acknowledgment:
00021 * "This product includes software developed by the
00022 * Apache Software Foundation (http://www.apache.org/)."
00023 * Alternately, this acknowledgment may appear in the software itself,
00024 * if and wherever such third-party acknowledgments normally appear.
00025 *
00026 * 4. The names "Xerces" and "Apache Software Foundation" must
00027 * not be used to endorse or promote products derived from this
00028 * software without prior written permission. For written
00029 * permission, please contact apache\@apache.org.
00030 *
00031 * 5. Products derived from this software may not be called "Apache",
00032 * nor may "Apache" appear in their name, without prior written
00033 * permission of the Apache Software Foundation.
00034 *
00035 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
00036 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
00037 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
00038 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
00039 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
00040 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
00041 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
00042 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
00043 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
00044 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
00045 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00046 * SUCH DAMAGE.
00047 * ====================================================================
00048 *
00049 * This software consists of voluntary contributions made by many
00050 * individuals on behalf of the Apache Software Foundation, and was
00051 * originally based on software copyright (c) 1999, International
00052 * Business Machines, Inc., http://www.ibm.com . For more information
00053 * on the Apache Software Foundation, please see
00054 * <http://www.apache.org/>.
00055 */
00056
00057 /*
00058 * $Id: XMLRegisterCleanup.hpp,v 1.3 2004/01/29 11:48:47 cargilld Exp $
00059 * $Log: XMLRegisterCleanup.hpp,v $
00060 * Revision 1.3 2004/01/29 11:48:47 cargilld
00061 * Code cleanup changes to get rid of various compiler diagnostic messages.
00062 *
00063 * Revision 1.2 2002/11/04 15:22:05 tng
00064 * C++ Namespace Support.
00065 *
00066 * Revision 1.1.1.1 2002/02/01 22:22:15 peiyongz
00067 * sane_include
00068 *
00069 * Revision 1.4 2001/10/25 21:55:29 peiyongz
00070 * copy ctor explicity declared private to prevent supprise.
00071 *
00072 * Revision 1.3 2001/10/24 18:13:06 peiyongz
00073 * CVS tag added
00074 *
00075 *
00076 */
00077
00078 #if !defined(XMLREGISTERCLEANUP_HPP)
00079 #define XMLREGISTERCLEANUP_HPP
00080
00081 #include <xercesc/util/Mutexes.hpp>
00082
00083 XERCES_CPP_NAMESPACE_BEGIN
00084
00085 // This is a mutex for exclusive use by this class
00086 extern XMLMutex* gXMLCleanupListMutex;
00087
00088 // This is the head of a list of XMLRegisterCleanup objects that
00089 // is used during XMLPlatformUtils::Terminate() to find objects to
00090 // clean up
00091 class XMLRegisterCleanup;
00092 extern XMLRegisterCleanup* gXMLCleanupList;
00093
00094 //
00095 // For internal use only.
00096 //
00097 // This class is used by the platform utilities class to support
00098 // reinitialisation of global/static data which is lazily created.
00099 // Since that data is widely spread out the platform utilities
00100 // class cannot know about them directly. So, the code that creates such
00101 // objects creates an registers a cleanup for the object. The platform
00102 // termination call will iterate the list and delete the objects.
00103 //
00104 // N.B. These objects need to be statically allocated. I couldn't think
00105 // of a neat way of ensuring this - can anyone else?
00106
00107 class XMLRegisterCleanup
00108 {
00109 public :
00110 // The cleanup function to be called on XMLPlatformUtils::Terminate()
00111 typedef void (*XMLCleanupFn)();
00112
00113 void doCleanup() {
00114 // When performing cleanup, we only do this once, but we can
00115 // cope if somehow we have been called twice.
00116 if (m_cleanupFn)
00117 m_cleanupFn();
00118
00119 // We need to remove "this" from the list
00120 // irregardless of the cleanup Function
00121 unregisterCleanup();
00122 }
00123
00124 // This function is called during initialisation of static data to
00125 // register a function to be called on XMLPlatformUtils::Terminate.
00126 // It gives an object that uses static data an opportunity to reset
00127 // such data.
00128 void registerCleanup(XMLCleanupFn cleanupFn) {
00129 // Store the cleanup function
00130 m_cleanupFn = cleanupFn;
00131
00132 // Add this object to the list head, if it is not already
00133 // present - which it shouldn't be.
00134 // This is done under a mutex to ensure thread safety.
00135 gXMLCleanupListMutex->lock();
00136 if (!m_nextCleanup && !m_prevCleanup) {
00137 m_nextCleanup = gXMLCleanupList;
00138 gXMLCleanupList = this;
00139
00140 if (m_nextCleanup)
00141 m_nextCleanup->m_prevCleanup = this;
00142 }
00143 gXMLCleanupListMutex->unlock();
00144 }
00145
00146 // This function can be called either from XMLPlatformUtils::Terminate
00147 // to state that the cleanup has been performed and should not be
00148 // performed again, or from code that you have written that determines
00149 // that cleanup is no longer necessary.
00150 void unregisterCleanup() {
00151 gXMLCleanupListMutex->lock();
00152
00153 //
00154 // To protect against some compiler's (eg hp11) optimization
00155 // to change "this" as they update gXMLCleanupList
00156 //
00157 // refer to
00158 // void XMLPlatformUtils::Terminate()
00159 // ...
00160 // while (gXMLCleanupList)
00161 // gXMLCleanupList->doCleanup();
00162 //
00163
00164 XMLRegisterCleanup *tmpThis = (XMLRegisterCleanup*) this;
00165
00166 // Unlink this object from the cleanup list
00167 if (m_nextCleanup) m_nextCleanup->m_prevCleanup = m_prevCleanup;
00168
00169 if (!m_prevCleanup) gXMLCleanupList = m_nextCleanup;
00170 else m_prevCleanup->m_nextCleanup = m_nextCleanup;
00171
00172 gXMLCleanupListMutex->unlock();
00173
00174 // Reset the object to the default state
00175 tmpThis->resetCleanup();
00176 }
00177
00178 // The default constructor sets a state that ensures that this object
00179 // will do nothing
00180XMLRegisterCleanup()
00181 {
00182 resetCleanup();
00183 }
00184
00185 private:
00186 // -----------------------------------------------------------------------
00187 // Unimplemented constructors and operators
00188 // -----------------------------------------------------------------------
00189 XMLRegisterCleanup(const XMLRegisterCleanup&);
00190 XMLRegisterCleanup& operator=(const XMLRegisterCleanup&);
00191
00192 // This is the cleanup function to be called
00193 XMLCleanupFn m_cleanupFn;
00194
00195 // These are list pointers to the next/prev cleanup function to be called
00196 XMLRegisterCleanup *m_nextCleanup, *m_prevCleanup;
00197
00198 // This function reinitialises the object to the default state
00199 void resetCleanup() {
00200 m_nextCleanup = 0;
00201 m_prevCleanup = 0;
00202 m_cleanupFn = 0;
00203 }
00204 };
00205
00206 XERCES_CPP_NAMESPACE_END
00207
00208 #endif