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diff --git a/unotools/inc/unotools/readwritemutexguard.hxx b/unotools/inc/unotools/readwritemutexguard.hxx
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+/*************************************************************************
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * Copyright 2000, 2010 Oracle and/or its affiliates.
+ *
+ * OpenOffice.org - a multi-platform office productivity suite
+ *
+ * This file is part of OpenOffice.org.
+ *
+ * OpenOffice.org is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 3
+ * only, as published by the Free Software Foundation.
+ *
+ * OpenOffice.org is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License version 3 for more details
+ * (a copy is included in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * version 3 along with OpenOffice.org.  If not, see
+ * <http://www.openoffice.org/license.html>
+ * for a copy of the LGPLv3 License.
+ *
+ ************************************************************************/
+
+#ifndef INCLUDED_UNOTOOLS_READWRITEMUTEXGUARD_HXX
+#define INCLUDED_UNOTOOLS_READWRITEMUTEXGUARD_HXX
+
+#include <osl/mutex.hxx>
+
+namespace utl {
+
+class ReadWriteGuard;
+class ReadWriteMutex
+{
+    friend class ReadWriteGuard;
+
+            sal_uInt32          nReadCount;
+            sal_uInt32          nBlockCriticalCount;
+            ::osl::Mutex*       pMutex;
+            ::osl::Mutex*       pWriteMutex;
+
+public:
+                                ReadWriteMutex()
+                                    : nReadCount(0)
+                                    , nBlockCriticalCount(0)
+                                    , pMutex( new ::osl::Mutex )
+                                    , pWriteMutex( new ::osl::Mutex )
+                                    {}
+                                ~ReadWriteMutex()
+                                    {
+                                        delete pMutex;
+                                        delete pWriteMutex;
+                                    }
+};
+
+
+namespace ReadWriteGuardMode {
+const sal_Int32 nWrite          = 0x01;
+const sal_Int32 nCriticalChange = 0x02 | nWrite;
+const sal_Int32 nBlockCritical  = 0x04;     // only a block, not a read, exclusive flag!
+}
+
+/** Enable multiple threads to read simultaneously, but a write blocks all
+    other reads and writes, and a read blocks any write.
+    Used in I18N wrappers to be able to maintain a single instance of a wrapper
+    for the standard Office locale.
+    NEVER construct a writing guard if there is already a reading guard in the
+    same context, the following will dead lock EVEN IN THE SAME THREAD!
+    void foo()
+    {
+        ReadWriteGuard aGuard1( aMutex );
+        bar();
+    }
+    void bar()
+    {
+        // waits forever for aGuard1
+        ReadWriteGuard aGuard2( aMutex, ReadWriteGuardMode::nWrite );
+    }
+ */
+class ReadWriteGuard
+{
+            ReadWriteMutex&     rMutex;
+            sal_Int32           nMode;
+public:
+                                ReadWriteGuard(
+                                    ReadWriteMutex& rMutex,
+                                    sal_Int32 nRequestMode = 0  // read only
+                                    );
+                                ~ReadWriteGuard();
+
+    /** Be careful with this, it does wait for ANY read to complete.
+        The following will dead lock EVEN IN THE SAME THREAD!
+        void foo()
+        {
+            ReadWriteGuard aGuard1( aMutex );
+            bar();
+        }
+        void bar()
+        {
+            ReadWriteGuard aGuard2( aMutex );
+            aGuard2.changeReadToWrite();    // waits forever for aGuard1
+        }
+     */
+            void                changeReadToWrite();
+};
+
+}   // namespace utl
+
+#endif // INCLUDED_UNOTOOLS_READWRITEMUTEXGUARD_HXX
+