office-gobmx/include/vcl/scopedbitmapaccess.hxx
Mark Page 677246466c Extend ScopedBitmapAccess and modify various classes to use it
Exception safety, ensure the Access classes are always destroyed.

Change-Id: I4889358476267853ffbd7fafc24950d84b4e9331
Reviewed-on: https://gerrit.libreoffice.org/31494
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
2016-12-02 11:18:16 +00:00

124 lines
3.6 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
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* 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
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* 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
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*/
#ifndef INCLUDED_VCL_SCOPEDBITMAPACCESS_HXX
#define INCLUDED_VCL_SCOPEDBITMAPACCESS_HXX
namespace vcl
{
/** This template handles BitmapAccess the RAII way.
Please don't use directly, but through the ready-made typedefs
ScopedReadAccess and ScopedWriteAccess in classes Bitmap and
AlphaMask.
Use as follows:
Bitmap aBitmap;
Bitmap::ScopedReadAccess pReadAccess( aBitmap );
pReadAccess->SetPixel()...
Bitmap aBitmap2;
Bitmap::ScopedWriteAccess pWriteAccess( bCond ? aBitmap2.AcquireWriteAccess() : 0, aBitmap2 );
if ( pWriteAccess )...
@attention for practical reasons, ScopedBitmapAccess stores a
reference to the provided bitmap, thus, make sure that the bitmap
specified at construction time lives at least as long as the
ScopedBitmapAccess.
*/
template < class Access, class Bitmap, Access* (Bitmap::* Acquire)() > class ScopedBitmapAccess
{
typedef ScopedBitmapAccess< Access, Bitmap, Acquire > self_type;
typedef bool (self_type::* unspecified_bool_type)() const;
public:
explicit ScopedBitmapAccess( Bitmap& rBitmap ) :
mpAccess( nullptr ),
mpBitmap( &rBitmap )
{
mpAccess = (mpBitmap->*Acquire)();
}
ScopedBitmapAccess( Access* pAccess, Bitmap& rBitmap ) :
mpAccess( pAccess ),
mpBitmap( &rBitmap )
{
}
ScopedBitmapAccess( ) :
mpAccess( nullptr ),
mpBitmap( nullptr )
{
}
// Move semantics
ScopedBitmapAccess &operator=(ScopedBitmapAccess&&other)
{
mpAccess=other.mpAccess;
mpBitmap=other.mpBitmap;
other.mpAccess = nullptr;
other.mpBitmap = nullptr;
return *this;
}
// Disable copy from lvalue.
ScopedBitmapAccess(const ScopedBitmapAccess&) = delete;
ScopedBitmapAccess &operator=(const ScopedBitmapAccess&) = delete;
~ScopedBitmapAccess()
{
if (mpAccess)
mpBitmap->ReleaseAccess( mpAccess );
}
void reset()
{
if (mpAccess)
{
mpBitmap->ReleaseAccess( mpAccess );
mpAccess = nullptr;
}
}
bool operator!() const { return !mpAccess; }
operator unspecified_bool_type() const
{
return mpAccess ? &self_type::operator! : 0;
}
Access* get() { return mpAccess; }
const Access* get() const { return mpAccess; }
Access* operator->() { return mpAccess; }
const Access* operator->() const { return mpAccess; }
Access& operator*() { return *mpAccess; }
const Access& operator*() const { return *mpAccess; }
private:
Access* mpAccess;
Bitmap* mpBitmap;
};
}
#endif // INCLUDED_VCL_SCOPEDBITMAPACCESS_HXX
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */