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1 /*
2  * Copyright (C) 2008, 2009 Apple 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  *
8  * 1.  Redistributions of source code must retain the above copyright
9  *     notice, this list of conditions and the following disclaimer.
10  * 2.  Redistributions in binary form must reproduce the above copyright
11  *     notice, this list of conditions and the following disclaimer in the
12  *     documentation and/or other materials provided with the distribution.
13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
14  *     its contributors may be used to endorse or promote products derived
15  *     from this software without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #ifndef EvalCodeCache_h
30 #define EvalCodeCache_h
31 
32 #include "JSGlobalObject.h"
33 #include "Nodes.h"
34 #include "Parser.h"
35 #include "SourceCode.h"
36 #include "UString.h"
37 #include <wtf/HashMap.h>
38 #include <wtf/RefPtr.h>
39 
40 namespace JSC {
41 
42     class EvalCodeCache {
43     public:
get(ExecState * exec,const UString & evalSource,ScopeChainNode * scopeChain,JSValue & exceptionValue)44         PassRefPtr<EvalNode> get(ExecState* exec, const UString& evalSource, ScopeChainNode* scopeChain, JSValue& exceptionValue)
45         {
46             RefPtr<EvalNode> evalNode;
47 
48             if (evalSource.size() < maxCacheableSourceLength && (*scopeChain->begin())->isVariableObject())
49                 evalNode = m_cacheMap.get(evalSource.rep());
50 
51             if (!evalNode) {
52                 int errorLine;
53                 UString errorMessage;
54 
55                 SourceCode source = makeSource(evalSource);
56                 evalNode = exec->globalData().parser->parse<EvalNode>(exec, exec->dynamicGlobalObject()->debugger(), source, &errorLine, &errorMessage);
57                 if (evalNode) {
58                     if (evalSource.size() < maxCacheableSourceLength && (*scopeChain->begin())->isVariableObject() && m_cacheMap.size() < maxCacheEntries)
59                         m_cacheMap.set(evalSource.rep(), evalNode);
60                 } else {
61                     exceptionValue = Error::create(exec, SyntaxError, errorMessage, errorLine, source.provider()->asID(), 0);
62                     return 0;
63                 }
64             }
65 
66             return evalNode.release();
67         }
68 
isEmpty()69         bool isEmpty() const { return m_cacheMap.isEmpty(); }
70 
markAggregate(MarkStack & markStack)71         void markAggregate(MarkStack& markStack)
72         {
73             EvalCacheMap::iterator end = m_cacheMap.end();
74             for (EvalCacheMap::iterator ptr = m_cacheMap.begin(); ptr != end; ++ptr)
75                 ptr->second->markAggregate(markStack);
76         }
77     private:
78         static const int maxCacheableSourceLength = 256;
79         static const int maxCacheEntries = 64;
80 
81         typedef HashMap<RefPtr<UString::Rep>, RefPtr<EvalNode> > EvalCacheMap;
82         EvalCacheMap m_cacheMap;
83     };
84 
85 } // namespace JSC
86 
87 #endif // EvalCodeCache_h
88