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diff --git a/include/comphelper/accessiblecontexthelper.hxx b/include/comphelper/accessiblecontexthelper.hxx
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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#ifndef INCLUDED_COMPHELPER_ACCESSIBLECONTEXTHELPER_HXX
+#define INCLUDED_COMPHELPER_ACCESSIBLECONTEXTHELPER_HXX
+
+#include <comphelper/accessiblecomponenthelper.hxx>
+#include <comphelper/solarmutex.hxx>
+
+
+namespace comphelper
+{
+
+
+    //= OContextEntryGuard
+
+    /** helper class for guarding the entry into OCommonAccessibleComponent methods.
+
+        <p>The class has two responsibilities:
+        <ul><li>it locks the mutex of an OCommonAccessibleComponent instance, as long as the guard lives</li>
+            <li>it checks if a given OCommonAccessibleComponent instance is alive, else an exception is thrown
+                our of the constructor of the guard</li>
+        </ul>
+        <br/>
+        This makes it your first choice (hopefully :) for guarding any interface method implementations of
+        you derived class.
+        </p>
+    */
+    class OContextEntryGuard : public ::osl::ClearableMutexGuard
+    {
+    public:
+        /** constructs the guard
+
+            <p>The given context (it's mutex, respectively) is locked, and an exception is thrown if the context
+            is not alive anymore. In the latter case, of course, the mutex is freed, again.</p>
+
+        @param _pContext
+            the context which shall be guarded
+        @precond <arg>_pContext</arg> != NULL
+        */
+        inline OContextEntryGuard( OCommonAccessibleComponent* _pContext );
+    };
+
+
+    inline OContextEntryGuard::OContextEntryGuard( OCommonAccessibleComponent* _pContext  )
+        : ::osl::ClearableMutexGuard( _pContext->GetMutex() )
+    {
+        _pContext->ensureAlive();
+    }
+
+
+    //= OExternalLockGuard
+
+    class OExternalLockGuard
+            :public osl::Guard<SolarMutex>
+            ,public OContextEntryGuard
+    {
+    public:
+        inline OExternalLockGuard( OCommonAccessibleComponent* _pContext );
+    };
+
+
+    inline OExternalLockGuard::OExternalLockGuard( OCommonAccessibleComponent* _pContext )
+        :osl::Guard<SolarMutex>( SolarMutex::get() )
+        ,OContextEntryGuard( _pContext )
+    {
+        // Only lock the external mutex,
+        // release the ::osl::Mutex of the OCommonAccessibleComponent instance.
+        // If you call into another UNO object with locked ::osl::Mutex,
+        // this may lead to dead locks.
+        clear();
+    }
+
+
+}   // namespace comphelper
+
+
+#endif // INCLUDED_COMPHELPER_ACCESSIBLECONTEXTHELPER_HXX
+
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */