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1 /*
2  * Copyright (C) 2009 Google Inc. All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions are
6  * met:
7  *
8  *     * Redistributions of source code must retain the above copyright
9  * notice, this list of conditions and the following disclaimer.
10  *     * Redistributions in binary form must reproduce the above
11  * copyright notice, this list of conditions and the following disclaimer
12  * in the documentation and/or other materials provided with the
13  * distribution.
14  *     * Neither the name of Google Inc. nor the names of its
15  * contributors may be used to endorse or promote products derived from
16  * this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #ifndef V8DOMMap_h
32 #define V8DOMMap_h
33 
34 #include <wtf/HashMap.h>
35 #include <wtf/OwnPtr.h>
36 #include <v8.h>
37 
38 namespace WebCore {
39     class DOMDataStore;
40     class Node;
41 #if ENABLE(SVG)
42     class SVGElementInstance;
43 #endif
44 
45     template <class KeyType, class ValueType> class AbstractWeakReferenceMap {
46     public:
AbstractWeakReferenceMap(v8::WeakReferenceCallback callback)47         AbstractWeakReferenceMap(v8::WeakReferenceCallback callback) : m_weakReferenceCallback(callback) { }
~AbstractWeakReferenceMap()48         virtual ~AbstractWeakReferenceMap() { }
49 
50         class Visitor {
51         public:
startMap()52             virtual void startMap() { }
endMap()53             virtual void endMap() { }
54             virtual void visitDOMWrapper(DOMDataStore* store, KeyType* key, v8::Persistent<ValueType> object) = 0;
55         protected:
~Visitor()56             virtual ~Visitor() { }
57         };
58 
59         virtual v8::Persistent<ValueType> get(KeyType* obj) = 0;
60         virtual void set(KeyType* obj, v8::Persistent<ValueType> wrapper) = 0;
61         virtual bool contains(KeyType* obj) = 0;
62         virtual void visit(DOMDataStore* store, Visitor* visitor) = 0;
63         virtual bool removeIfPresent(KeyType*, v8::Persistent<ValueType>) = 0;
64         virtual void clear() = 0;
65 
weakReferenceCallback()66         v8::WeakReferenceCallback weakReferenceCallback() { return m_weakReferenceCallback; }
67     private:
68         v8::WeakReferenceCallback m_weakReferenceCallback;
69     };
70 
71     typedef AbstractWeakReferenceMap<Node, v8::Object> DOMNodeMapping;
72 
73     // A table of wrappers with weak pointers.
74     // This table allows us to avoid track wrapped objects for debugging
75     // and for ensuring that we don't double wrap the same object.
76     template<class KeyType, class ValueType> class WeakReferenceMap : public AbstractWeakReferenceMap<KeyType, ValueType> {
77     public:
78         typedef AbstractWeakReferenceMap<KeyType, ValueType> Parent;
WeakReferenceMap(v8::WeakReferenceCallback callback)79         WeakReferenceMap(v8::WeakReferenceCallback callback) : Parent(callback) { }
~WeakReferenceMap()80         virtual ~WeakReferenceMap() { }
81 
82         // Get the JS wrapper object of an object.
get(KeyType * obj)83         virtual v8::Persistent<ValueType> get(KeyType* obj)
84         {
85             ValueType* wrapper = m_map.get(obj);
86             return wrapper ? v8::Persistent<ValueType>(wrapper) : v8::Persistent<ValueType>();
87         }
88 
set(KeyType * obj,v8::Persistent<ValueType> wrapper)89         virtual void set(KeyType* obj, v8::Persistent<ValueType> wrapper)
90         {
91             ASSERT(!m_map.contains(obj));
92             wrapper.MakeWeak(obj, Parent::weakReferenceCallback());
93             m_map.set(obj, *wrapper);
94         }
95 
forget(KeyType * obj)96         virtual void forget(KeyType* obj)
97         {
98             ASSERT(obj);
99             ValueType* wrapper = m_map.take(obj);
100             if (!wrapper)
101                 return;
102 
103             v8::Persistent<ValueType> handle(wrapper);
104             handle.Dispose();
105             handle.Clear();
106         }
107 
removeIfPresent(KeyType * key,v8::Persistent<ValueType> value)108         bool removeIfPresent(KeyType* key, v8::Persistent<ValueType> value)
109         {
110             typename HashMap<KeyType*, ValueType*>::iterator it = m_map.find(key);
111             if (it == m_map.end() || it->second != *value)
112                 return false;
113 
114             m_map.remove(it);
115             value.Dispose();
116             return true;
117         }
118 
clear()119         void clear()
120         {
121             m_map.clear();
122         }
123 
contains(KeyType * obj)124         bool contains(KeyType* obj) { return m_map.contains(obj); }
125 
visit(DOMDataStore * store,typename Parent::Visitor * visitor)126         virtual void visit(DOMDataStore* store, typename Parent::Visitor* visitor)
127         {
128             visitor->startMap();
129             typename HashMap<KeyType*, ValueType*>::iterator it = m_map.begin();
130             for (; it != m_map.end(); ++it)
131                 visitor->visitDOMWrapper(store, it->first, v8::Persistent<ValueType>(it->second));
132             visitor->endMap();
133         }
134 
135     protected:
136         HashMap<KeyType*, ValueType*> m_map;
137     };
138 
139     template <class KeyType> class DOMWrapperMap : public WeakReferenceMap<KeyType, v8::Object> {
140     public:
DOMWrapperMap(v8::WeakReferenceCallback callback)141         DOMWrapperMap(v8::WeakReferenceCallback callback) : WeakReferenceMap<KeyType, v8::Object>(callback) { }
142     };
143 
144     // An opaque class that represents a set of DOM wrappers.
145     class DOMDataStore;
146 
147     // A utility class to manage the lifetime of set of DOM wrappers.
148     class DOMDataStoreHandle {
149     public:
150         DOMDataStoreHandle();
151         ~DOMDataStoreHandle();
152 
getStore()153         DOMDataStore* getStore() const { return m_store.get(); }
154 
155     private:
156         OwnPtr<DOMDataStore> m_store;
157     };
158 
159     // A map from DOM node to its JS wrapper.
160     DOMNodeMapping& getDOMNodeMap();
161     void visitDOMNodesInCurrentThread(DOMWrapperMap<Node>::Visitor*);
162 
163     // A map from a DOM object (non-node) to its JS wrapper. This map does not contain the DOM objects which can have pending activity (active dom objects).
164     DOMWrapperMap<void>& getDOMObjectMap();
165     void visitDOMObjectsInCurrentThread(DOMWrapperMap<void>::Visitor*);
166 
167     // A map from a DOM object to its JS wrapper for DOM objects which can have pending activity.
168     DOMWrapperMap<void>& getActiveDOMObjectMap();
169     void visitActiveDOMObjectsInCurrentThread(DOMWrapperMap<void>::Visitor*);
170 
171     // This should be called to remove all DOM objects associated with the current thread when it is tearing down.
172     void removeAllDOMObjectsInCurrentThread();
173 
174 #if ENABLE(SVG)
175     // A map for SVGElementInstances to its JS wrapper.
176     DOMWrapperMap<SVGElementInstance>& getDOMSVGElementInstanceMap();
177     void visitSVGElementInstancesInCurrentThread(DOMWrapperMap<SVGElementInstance>::Visitor*);
178 #endif
179 
180     void enableFasterDOMStoreAccess();
181 } // namespace WebCore
182 
183 #endif // V8DOMMap_h
184