libreoffice/include/cppuhelper/weakref.hxx

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 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
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 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
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 *   ownership. The ASF licenses this file to you under the Apache
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 *   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_CPPUHELPER_WEAKREF_HXX
#define INCLUDED_CPPUHELPER_WEAKREF_HXX

#include <com/sun/star/uno/XInterface.hpp>
#include <cppuhelper/cppuhelperdllapi.h>


namespace com
{
namespace sun
{
namespace star
{
namespace uno
{

class OWeakRefListener;

/** The WeakReferenceHelper holds a weak reference to an object. This object must implement
    the com::sun::star::uno::XWeak interface.  The implementation is thread safe.
*/
class CPPUHELPER_DLLPUBLIC WeakReferenceHelper
{
public:
    /** Default ctor.  Creates an empty weak reference.
    */
    inline WeakReferenceHelper() SAL_THROW(())
        : m_pImpl( 0 )
        {}

    /** Copy ctor.  Initialize this reference with the same interface as in rWeakRef.

        @param rWeakRef another weak ref
    */
    WeakReferenceHelper( const WeakReferenceHelper & rWeakRef ) SAL_THROW(());
    /** Initialize this reference with the hard interface reference xInt. If the implementation
        behind xInt does not support XWeak or XInt is null then this reference will be null.

        @param xInt another hard interface reference
    */
    WeakReferenceHelper( const ::com::sun::star::uno::Reference< ::com::sun::star::uno::XInterface > & xInt )
        SAL_THROW(());
    /** Releases this reference.
    */
    ~WeakReferenceHelper() SAL_THROW(());

    /** Releases this reference and takes over rWeakRef.

        @param rWeakRef another weak ref
    */
    WeakReferenceHelper & SAL_CALL operator = ( const WeakReferenceHelper & rWeakRef ) SAL_THROW(());

    /** Releases this reference and takes over hard reference xInt.
        If the implementation behind xInt does not support XWeak
        or XInt is null, then this reference is null.

        @param xInt another hard reference
    */
    WeakReferenceHelper & SAL_CALL operator = (
            const ::com::sun::star::uno::Reference<
                ::com::sun::star::uno::XInterface > & xInt ) SAL_THROW(());

    /** Returns true if both weak refs reference to the same object.

        @param rObj another weak ref
        @return true, if both weak refs reference to the same object.
    */
    inline bool SAL_CALL operator == ( const WeakReferenceHelper & rObj ) const SAL_THROW(())
        { return (get() == rObj.get()); }

    /**  Gets a hard reference to the object.

         @return hard reference or null, if the weakly referenced interface has gone
    */
    ::com::sun::star::uno::Reference< ::com::sun::star::uno::XInterface > SAL_CALL get() const SAL_THROW(());
    /**  Gets a hard reference to the object.

         @return hard reference or null, if the weakly referenced interface has gone
    */
    inline SAL_CALL operator Reference< XInterface > () const SAL_THROW(())
        { return get(); }

    /** Releases this reference.

        @since UDK 3.2.12
    */
    void SAL_CALL clear() SAL_THROW(());

protected:
    /// @cond INTERNAL
    OWeakRefListener * m_pImpl;
    /// @endcond
};

/** The WeakReference<> holds a weak reference to an object. This object must implement
    the com::sun::star::uno::XWeak interface.  The implementation is thread safe.

    @tparam interface_type type of interface
*/
template< class interface_type >
class WeakReference : public WeakReferenceHelper
{
public:
    /** Default ctor.  Creates an empty weak reference.
    */
    inline WeakReference() SAL_THROW(())
        : WeakReferenceHelper()
        {}

    /** Copy ctor.  Initialize this reference with a hard reference.

        @param rRef another hard ref
    */
    inline WeakReference( const Reference< interface_type > & rRef ) SAL_THROW(())
        : WeakReferenceHelper( rRef )
        {}

    /** Releases this reference and takes over hard reference xInt.
        If the implementation behind xInt does not support XWeak
        or XInt is null, then this reference is null.

        @param xInt another hard reference

        @since UDK 3.2.12
    */
    WeakReference & SAL_CALL operator = (
            const ::com::sun::star::uno::Reference< interface_type > & xInt )
        SAL_THROW(())
        { WeakReferenceHelper::operator=(xInt); return *this; }

    /**  Gets a hard reference to the object.

         @return hard reference or null, if the weakly referenced interface has gone
    */
    inline SAL_CALL operator Reference< interface_type > () const SAL_THROW(())
        { return Reference< interface_type >::query( get() ); }
};

}
}
}
}

#endif

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