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21 
22 
23 
24 #ifndef INCLUDED_SLIDESHOW_SHAPEATTRIBUTELAYERHOLDER_HXX
25 #define INCLUDED_SLIDESHOW_SHAPEATTRIBUTELAYERHOLDER_HXX
26 
27 #include "attributableshape.hxx"
28 #include "shapeattributelayer.hxx"
29 
30 #include <boost/noncopyable.hpp>
31 
32 namespace slideshow
33 {
34     namespace internal
35     {
36         /** Holds a ShapeAttributeLayer, together with the associated
37             Shape
38 
39             Use this class to hold ShapeAttributeLayer objects the
40             RAII way. When this object gets deleted, it will
41             automatically revoke the attribute layer for the given
42             shape (this encapsulates the somewhat clumsy notification
43             process that is required for shape and attribute layer
44             interaction).
45          */
46         class ShapeAttributeLayerHolder : private boost::noncopyable
47         {
48         public:
49             /** Create a ShapeAttributeLayerHolder instance.
50 
51             	This constructor creates an empty attribute holder, to
52             	generate an attribute layer, you have to manually call
53             	createAttributeLayer().
54              */
ShapeAttributeLayerHolder()55             ShapeAttributeLayerHolder() :
56                 mpShape(),
57                 mpAttributeLayer()
58             {
59             }
60 
~ShapeAttributeLayerHolder()61             ~ShapeAttributeLayerHolder()
62             {
63                 reset(); // ensures that the last attribute layer is
64                          // correctly deregistered from the shape.
65             }
66 
reset()67             void reset()
68             {
69                 if( mpShape && mpAttributeLayer )
70                     mpShape->revokeAttributeLayer( mpAttributeLayer );
71             }
72 
73             /** This constructor receives a pointer to the Shape, from
74             	which attribute layers should be generated. Initially,
75             	this object does not create an attribute layer, you
76             	have to manually call createAttributeLayer().
77 
78                 @param rShape
79                 Shape for which attribute layers should be generated.
80             */
createAttributeLayer(const AttributableShapeSharedPtr & rShape)81             bool createAttributeLayer( const AttributableShapeSharedPtr& rShape )
82             {
83                 reset();
84 
85                 mpShape = rShape;
86 
87                 if( mpShape )
88                     mpAttributeLayer = mpShape->createAttributeLayer();
89 
90                 return (mpAttributeLayer.get() != NULL);
91             }
92 
get() const93             ShapeAttributeLayerSharedPtr get() const
94             {
95                 return mpAttributeLayer;
96             }
97 
98         private:
99             AttributableShapeSharedPtr		mpShape;
100             ShapeAttributeLayerSharedPtr	mpAttributeLayer;
101         };
102 
103     }
104 }
105 
106 #endif /* INCLUDED_SLIDESHOW_SHAPEATTRIBUTELAYERHOLDER_HXX */
107