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#include "SVGAnimatedProperty.h"
24#include "SVGElement.h"
25#include "SVGProperty.h"
26#include <wtf/WeakPtr.h>
27
28namespace WebCore {
29
30class SVGPropertyTearOffBase : public SVGProperty {
31public:
32    virtual void detachWrapper() = 0;
33};
34
35template<typename PropertyType>
36class SVGPropertyTearOff : public SVGPropertyTearOffBase {
37public:
38    typedef SVGPropertyTearOff<PropertyType> Self;
39
40    // Used for child types (baseVal/animVal) of a SVGAnimated* property (for example: SVGAnimatedLength::baseVal()).
41    // Also used for list tear offs (for example: text.x.baseVal.getItem(0)).
42    static PassRefPtr<Self> create(SVGAnimatedProperty* animatedProperty, SVGPropertyRole role, PropertyType& value)
43    {
44        ASSERT(animatedProperty);
45        return adoptRef(new Self(animatedProperty, role, value));
46    }
47
48    // Used for non-animated POD types (for example: SVGSVGElement::createSVGLength()).
49    static PassRefPtr<Self> create(const PropertyType& initialValue)
50    {
51        return adoptRef(new Self(initialValue));
52    }
53
54    PropertyType& propertyReference() { return *m_value; }
55    SVGAnimatedProperty* animatedProperty() const { return m_animatedProperty; }
56
57    void setValue(PropertyType& value)
58    {
59        if (m_valueIsCopy) {
60            detachChildren();
61            delete m_value;
62        }
63        m_valueIsCopy = false;
64        m_value = &value;
65    }
66
67    void setAnimatedProperty(SVGAnimatedProperty* animatedProperty)
68    {
69        m_animatedProperty = animatedProperty;
70
71        if (m_animatedProperty)
72            m_contextElement = m_animatedProperty->contextElement();
73    }
74
75    SVGElement* contextElement() const
76    {
77        if (!m_animatedProperty || m_valueIsCopy)
78            return 0;
79        return m_contextElement.get();
80    }
81
82    void addChild(WeakPtr<SVGPropertyTearOffBase> child)
83    {
84        m_childTearOffs.append(child);
85    }
86
87    virtual void detachWrapper() override
88    {
89        if (m_valueIsCopy)
90            return;
91
92        detachChildren();
93
94        // Switch from a live value, to a non-live value.
95        // For example: <text x="50"/>
96        // var item = text.x.baseVal.getItem(0);
97        // text.setAttribute("x", "100");
98        // item.value still has to report '50' and it has to be possible to modify 'item'
99        // w/o changing the "new item" (with x=100) in the text element.
100        // Whenever the XML DOM modifies the "x" attribute, all existing wrappers are detached, using this function.
101        m_value = new PropertyType(*m_value);
102        m_valueIsCopy = true;
103        m_animatedProperty = 0;
104    }
105
106    virtual void commitChange() override
107    {
108        if (!m_animatedProperty || m_valueIsCopy)
109            return;
110        m_animatedProperty->commitChange();
111    }
112
113    virtual bool isReadOnly() const override
114    {
115        if (m_role == AnimValRole)
116            return true;
117        if (m_animatedProperty && m_animatedProperty->isReadOnly())
118            return true;
119        return false;
120    }
121
122protected:
123    SVGPropertyTearOff(SVGAnimatedProperty* animatedProperty, SVGPropertyRole role, PropertyType& value)
124        : m_animatedProperty(animatedProperty)
125        , m_role(role)
126        , m_value(&value)
127        , m_valueIsCopy(false)
128    {
129        // Using operator & is completely fine, as SVGAnimatedProperty owns this reference,
130        // and we're guaranteed to live as long as SVGAnimatedProperty does.
131
132        if (m_animatedProperty)
133            m_contextElement = m_animatedProperty->contextElement();
134    }
135
136    SVGPropertyTearOff(const PropertyType& initialValue)
137        : m_animatedProperty(0)
138        , m_role(UndefinedRole)
139        , m_value(new PropertyType(initialValue))
140        , m_valueIsCopy(true)
141    {
142    }
143
144    virtual ~SVGPropertyTearOff()
145    {
146        if (m_valueIsCopy) {
147            detachChildren();
148            delete m_value;
149        }
150    }
151
152    void detachChildren()
153    {
154        for (const auto& childTearOff : m_childTearOffs) {
155            if (childTearOff.get())
156                childTearOff.get()->detachWrapper();
157        }
158        m_childTearOffs.clear();
159    }
160
161    RefPtr<SVGElement> m_contextElement;
162    SVGAnimatedProperty* m_animatedProperty;
163    SVGPropertyRole m_role;
164    PropertyType* m_value;
165    Vector<WeakPtr<SVGPropertyTearOffBase>> m_childTearOffs;
166    bool m_valueIsCopy : 1;
167};
168
169}
170
171#endif // SVGPropertyTearOff_h
172