Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 151 insertions, 0 deletions

diff --git a/canvas/inc/vclwrapper.hxx b/canvas/inc/vclwrapper.hxx
new file mode 100644
index 000000000..3c1dfbf2d
--- /dev/null
+++ b/canvas/inc/vclwrapper.hxx
@@ -0,0 +1,151 @@
+/* -*- 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 .
+ */
+
+#pragma once
+
+#include <vcl/svapp.hxx>
+#include <memory>
+
+namespace canvas
+{
+    namespace vcltools
+    {
+        /** This helper template wraps VCL objects, and protects
+            object deletion with the Solar mutex. All other operations
+            are unprotected, this must be handled by client code.
+
+            The reason for this template is the fact that VCL objects
+            hold by value in uno::Reference-handled classes are
+            deleted without having the chance to get inbetween and
+            lock the solar mutex.
+
+            This template handles that problem transparently, the only
+            inconvenience is the fact that object member access now
+            has to be performed via operator->, since . is not
+            overloadable.
+
+            Otherwise, the template preserves the value semantics of
+            the wrapped object, that is, copy operations are performed
+            not by copying pointers, but by copying the underlying
+            object. This includes constness, i.e. on a const
+            VCLObject, only const methods of the wrapped object can be
+            called. Simply imagine this to be a value object of type
+            "template argument", with the only peculiarity that
+            member/method access is performed by operator-> instead of
+            the non-existing "operator.".
+         */
+        template< class Wrappee_ > class VCLObject
+        {
+        public:
+            typedef Wrappee_ Wrappee;
+
+            VCLObject() :
+                mpWrappee( new Wrappee() )
+            {
+            }
+
+            // no explicit here. VCLObjects should be freely
+            // constructible with Wrappees, and AFAIK there is no other
+            // implicit conversion path that could cause harm here
+            VCLObject( std::unique_ptr<Wrappee> pWrappee ) :
+                mpWrappee( pWrappee )
+            {
+            }
+
+            // This object has value semantics, thus, forward copy
+            // to wrappee
+            VCLObject( const VCLObject& rOrig )
+            {
+                if( rOrig.mpWrappee )
+                    mpWrappee = new Wrappee( *rOrig.mpWrappee );
+                else
+                    mpWrappee = nullptr;
+            }
+
+            VCLObject(VCLObject&& rOrig) noexcept
+                : mpWrappee(std::move(rOrig.mpWrappee))
+            {
+            }
+
+            // This object has value semantics, thus, forward copy
+            // to wrappee
+            VCLObject( const Wrappee& rOrig ) :
+                mpWrappee( new Wrappee( rOrig ) )
+            {
+            }
+
+            // This object has value semantics, thus, forward
+            // assignment to wrappee
+            VCLObject& operator=( const VCLObject& rhs )
+            {
+                if (this != &rhs)
+                {
+                    if( mpWrappee )
+                    {
+                        if( rhs.mpWrappee )
+                            *mpWrappee = *rhs.mpWrappee;
+                    }
+                    else
+                    {
+                        if( rhs.mpWrappee )
+                            mpWrappee = new Wrappee( *rhs.mpWrappee );
+                    }
+                }
+                return *this;
+            }
+
+            VCLObject& operator=(VCLObject&& rhs) noexcept
+            {
+                std::swap(mpWrappee, rhs.mpWrappee);
+
+                return *this;
+            }
+
+            ~VCLObject()
+            {
+                // This here is the whole purpose of the template:
+                // protecting object deletion with the solar mutex
+                SolarMutexGuard aGuard;
+
+                mpWrappee.reset();
+            }
+
+            Wrappee*        operator->() { return mpWrappee.get(); }
+            const Wrappee*  operator->() const { return mpWrappee.get(); }
+
+            Wrappee&        operator*() { return *mpWrappee; }
+            const Wrappee&  operator*() const { return *mpWrappee; }
+
+            Wrappee&        get() { return *mpWrappee; }
+            const Wrappee&  get() const { return *mpWrappee; }
+
+            void swap( VCLObject& rOther )
+            {
+                ::std::swap( mpWrappee, rOther.mpWrappee );
+            }
+
+        private:
+
+            std::unique_ptr<Wrappee> mpWrappee;
+        };
+
+    }
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */