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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
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23  * THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 
26 #ifndef V8ValueCache_h
27 #define V8ValueCache_h
28 
29 #include "bindings/v8/UnsafePersistent.h"
30 #include <v8.h>
31 #include "wtf/HashMap.h"
32 #include "wtf/RefPtr.h"
33 #include "wtf/text/AtomicString.h"
34 #include "wtf/text/WTFString.h"
35 
36 namespace WebCore {
37 
38 class StringCache {
39 public:
StringCache()40     StringCache() { }
41 
v8ExternalString(StringImpl * stringImpl,v8::Isolate * isolate)42     v8::Handle<v8::String> v8ExternalString(StringImpl* stringImpl, v8::Isolate* isolate)
43     {
44         ASSERT(stringImpl);
45         if (m_lastStringImpl.get() == stringImpl)
46             return m_lastV8String.newLocal(isolate);
47         return v8ExternalStringSlow(stringImpl, isolate);
48     }
49 
setReturnValueFromString(v8::ReturnValue<v8::Value> returnValue,StringImpl * stringImpl)50     void setReturnValueFromString(v8::ReturnValue<v8::Value> returnValue, StringImpl* stringImpl)
51     {
52         ASSERT(stringImpl);
53         if (m_lastStringImpl.get() == stringImpl)
54             returnValue.Set(*m_lastV8String.persistent());
55         else
56             setReturnValueFromStringSlow(returnValue, stringImpl);
57     }
58 
59 private:
60     static void setWeakCallback(const v8::WeakCallbackData<v8::String, StringImpl>&);
61 
62     v8::Handle<v8::String> v8ExternalStringSlow(StringImpl*, v8::Isolate*);
63     void setReturnValueFromStringSlow(v8::ReturnValue<v8::Value>, StringImpl*);
64     v8::Local<v8::String> createStringAndInsertIntoCache(StringImpl*, v8::Isolate*);
65 
66     HashMap<StringImpl*, UnsafePersistent<v8::String> > m_stringCache;
67     UnsafePersistent<v8::String> m_lastV8String;
68     // Note: RefPtr is a must as we cache by StringImpl* equality, not identity
69     // hence lastStringImpl might be not a key of the cache (in sense of identity)
70     // and hence it's not refed on addition.
71     RefPtr<StringImpl> m_lastStringImpl;
72 };
73 
74 } // namespace WebCore
75 
76 #endif // V8ValueCache_h
77