/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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 * 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_VCL_SCOPEDBITMAPACCESS_HXX
#define INCLUDED_VCL_SCOPEDBITMAPACCESS_HXX

#include <sal/types.h>

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;
    BitmapScopedWriteAccess 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
{
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() COVERITY_NOEXCEPT_FALSE
    {
        if (mpAccess)
           mpBitmap->ReleaseAccess( mpAccess );
    }

    void reset()
    {
        if (mpAccess)
        {
           mpBitmap->ReleaseAccess( mpAccess );
           mpAccess = nullptr;
        }
    }

    bool operator!() const { return !mpAccess; }
    explicit operator bool() const
    {
        return mpAccess;
    }

    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

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