/src/libreoffice/canvas/inc/vclwrapper.hxx

Source
/* -*- 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: */

Line	Count	Source
1		/* -- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -- */
2		/*
3		* This file is part of the LibreOffice project.
4		*
5		* This Source Code Form is subject to the terms of the Mozilla Public
6		* License, v. 2.0. If a copy of the MPL was not distributed with this
7		* file, You can obtain one at http://mozilla.org/MPL/2.0/.
8		*
9		* This file incorporates work covered by the following license notice:
10		*
11		* Licensed to the Apache Software Foundation (ASF) under one or more
12		* contributor license agreements. See the NOTICE file distributed
13		* with this work for additional information regarding copyright
14		* ownership. The ASF licenses this file to you under the Apache
15		* License, Version 2.0 (the "License"); you may not use this file
16		* except in compliance with the License. You may obtain a copy of
17		* the License at http://www.apache.org/licenses/LICENSE-2.0 .
18		*/
19
20		#pragma once
21
22		#include <vcl/svapp.hxx>
23		#include <memory>
24
25		namespace canvas
26		{
27		namespace vcltools
28		{
29		/** This helper template wraps VCL objects, and protects
30		object deletion with the Solar mutex. All other operations
31		are unprotected, this must be handled by client code.
32
33		The reason for this template is the fact that VCL objects
34		hold by value in uno::Reference-handled classes are
35		deleted without having the chance to get inbetween and
36		lock the solar mutex.
37
38		This template handles that problem transparently, the only
39		inconvenience is the fact that object member access now
40		has to be performed via operator->, since . is not
41		overloadable.
42
43		Otherwise, the template preserves the value semantics of
44		the wrapped object, that is, copy operations are performed
45		not by copying pointers, but by copying the underlying
46		object. This includes constness, i.e. on a const
47		VCLObject, only const methods of the wrapped object can be
48		called. Simply imagine this to be a value object of type
49		"template argument", with the only peculiarity that
50		member/method access is performed by operator-> instead of
51		the non-existing "operator.".
52		*/
53		template< class Wrappee_ > class VCLObject
54		{
55		public:
56		typedef Wrappee_ Wrappee;
57
58		VCLObject() :
59	0	mpWrappee( new Wrappee() )
60	0	{
61	0	}
62
63		// no explicit here. VCLObjects should be freely
64		// constructible with Wrappees, and AFAIK there is no other
65		// implicit conversion path that could cause harm here
66		VCLObject( std::unique_ptr<Wrappee> pWrappee ) :
67		mpWrappee( pWrappee )
68		{
69		}
70
71		// This object has value semantics, thus, forward copy
72		// to wrappee
73		VCLObject( const VCLObject& rOrig )
74		{
75		if( rOrig.mpWrappee )
76		mpWrappee = new Wrappee( *rOrig.mpWrappee );
77		else
78		mpWrappee = nullptr;
79		}
80
81		VCLObject(VCLObject&& rOrig) noexcept
82		: mpWrappee(std::move(rOrig.mpWrappee))
83		{
84		}
85
86		// This object has value semantics, thus, forward copy
87		// to wrappee
88		VCLObject( const Wrappee& rOrig ) :
89	0	mpWrappee( new Wrappee( rOrig ) )
90	0	{
91	0	} Unexecuted instantiation: canvas::vcltools::VCLObject<vcl::Font>::VCLObject(vcl::Font const&) Unexecuted instantiation: canvas::vcltools::VCLObject<Bitmap>::VCLObject(Bitmap const&)
92
93		// This object has value semantics, thus, forward
94		// assignment to wrappee
95		VCLObject& operator=( const VCLObject& rhs )
96		{
97		if (this != &rhs)
98		{
99		if( mpWrappee )
100		{
101		if( rhs.mpWrappee )
102		mpWrappee = rhs.mpWrappee;
103		}
104		else
105		{
106		if( rhs.mpWrappee )
107		mpWrappee = new Wrappee( *rhs.mpWrappee );
108		}
109		}
110		return *this;
111		}
112
113		VCLObject& operator=(VCLObject&& rhs) noexcept
114	0	{
115	0	std::swap(mpWrappee, rhs.mpWrappee);
116
117	0	return *this;
118	0	}
119
120		~VCLObject()
121	0	{
122		// This here is the whole purpose of the template:
123		// protecting object deletion with the solar mutex
124	0	SolarMutexGuard aGuard;
125
126	0	mpWrappee.reset();
127	0	} Unexecuted instantiation: canvas::vcltools::VCLObject<Bitmap>::~VCLObject() Unexecuted instantiation: canvas::vcltools::VCLObject<vcl::Font>::~VCLObject()
128
129	0	Wrappee* operator->() { return mpWrappee.get(); } Unexecuted instantiation: canvas::vcltools::VCLObject<vcl::Font>::operator->() Unexecuted instantiation: canvas::vcltools::VCLObject<Bitmap>::operator->()
130	0	const Wrappee* operator->() const { return mpWrappee.get(); }
131
132	0	Wrappee& operator() { return mpWrappee; }
133	0	const Wrappee& operator() const { return mpWrappee; } Unexecuted instantiation: canvas::vcltools::VCLObject<vcl::Font>::operator() const Unexecuted instantiation: canvas::vcltools::VCLObject<Bitmap>::operator() const
134
135	0	Wrappee& get() { return *mpWrappee; }
136		const Wrappee& get() const { return *mpWrappee; }
137
138		void swap( VCLObject& rOther )
139		{
140		::std::swap( mpWrappee, rOther.mpWrappee );
141		}
142
143		private:
144
145		std::unique_ptr<Wrappee> mpWrappee;
146		};
147
148		}
149		}
150
151		/* vim:set shiftwidth=4 softtabstop=4 expandtab: */

Coverage Report

Created: 2026-02-14 09:37