1/*
2 * Copyright (C) Research In Motion Limited 2010. All rights reserved.
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public License
15 * along with this library; see the file COPYING.LIB.  If not, write to
16 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
17 * Boston, MA 02110-1301, USA.
18 */
19
20#ifndef SVGPropertyTearOff_h
21#define SVGPropertyTearOff_h
22
23#if ENABLE(SVG)
24#include "SVGAnimatedProperty.h"
25#include "SVGElement.h"
26#include "SVGProperty.h"
27
28namespace WebCore {
29
30template<typename PropertyType>
31class SVGPropertyTearOff : public SVGProperty {
32public:
33    typedef SVGPropertyTearOff<PropertyType> Self;
34
35    // Used for child types (baseVal/animVal) of a SVGAnimated* property (for example: SVGAnimatedLength::baseVal()).
36    // Also used for list tear offs (for example: text.x.baseVal.getItem(0)).
37    static PassRefPtr<Self> create(SVGAnimatedProperty* animatedProperty, SVGPropertyRole role, PropertyType& value)
38    {
39        ASSERT(animatedProperty);
40        return adoptRef(new Self(animatedProperty, role, value));
41    }
42
43    // Used for non-animated POD types (for example: SVGSVGElement::createSVGLength()).
44    static PassRefPtr<Self> create(const PropertyType& initialValue)
45    {
46        return adoptRef(new Self(initialValue));
47    }
48
49    PropertyType& propertyReference() { return *m_value; }
50    SVGAnimatedProperty* animatedProperty() const { return m_animatedProperty.get(); }
51
52    // Used only by the list tear offs!
53    void setValue(PropertyType& value)
54    {
55        if (m_valueIsCopy)
56            delete m_value;
57        m_valueIsCopy = false;
58        m_value = &value;
59    }
60
61    void setAnimatedProperty(SVGAnimatedProperty* animatedProperty) { m_animatedProperty = animatedProperty; }
62
63    SVGElement* contextElement() const
64    {
65        if (!m_animatedProperty || m_valueIsCopy)
66            return 0;
67        return m_animatedProperty->contextElement();
68    }
69
70    void detachWrapper()
71    {
72        if (m_valueIsCopy)
73            return;
74
75        // Switch from a live value, to a non-live value.
76        // For example: <text x="50"/>
77        // var item = text.x.baseVal.getItem(0);
78        // text.setAttribute("x", "100");
79        // item.value still has to report '50' and it has to be possible to modify 'item'
80        // w/o changing the "new item" (with x=100) in the text element.
81        // Whenever the XML DOM modifies the "x" attribute, all existing wrappers are detached, using this function.
82        m_value = new PropertyType(*m_value);
83        m_valueIsCopy = true;
84        m_animatedProperty = 0;
85    }
86
87    virtual void commitChange()
88    {
89        if (!m_animatedProperty || m_valueIsCopy)
90            return;
91        m_animatedProperty->commitChange();
92    }
93
94    virtual SVGPropertyRole role() const { return m_role; }
95
96protected:
97    SVGPropertyTearOff(SVGAnimatedProperty* animatedProperty, SVGPropertyRole role, PropertyType& value)
98        : m_animatedProperty(animatedProperty)
99        , m_role(role)
100        , m_value(&value)
101        , m_valueIsCopy(false)
102    {
103        // Using operator & is completly fine, as SVGAnimatedProperty owns this reference,
104        // and we're guaranteed to live as long as SVGAnimatedProperty does.
105    }
106
107    SVGPropertyTearOff(const PropertyType& initialValue)
108        : m_animatedProperty(0)
109        , m_role(UndefinedRole)
110        , m_value(new PropertyType(initialValue))
111        , m_valueIsCopy(true)
112    {
113    }
114
115    virtual ~SVGPropertyTearOff()
116    {
117        if (m_valueIsCopy)
118            delete m_value;
119    }
120
121    RefPtr<SVGAnimatedProperty> m_animatedProperty;
122    SVGPropertyRole m_role;
123    PropertyType* m_value;
124    bool m_valueIsCopy : 1;
125};
126
127}
128
129#endif // ENABLE(SVG)
130#endif // SVGPropertyTearOff_h
131