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 "Executable.h"
33#include "JSGlobalObject.h"
34#include "Nodes.h"
35#include "Parser.h"
36#include "SourceCode.h"
37#include "UString.h"
38#include <wtf/HashMap.h>
39#include <wtf/RefPtr.h>
40#include <wtf/text/StringHash.h>
41
42namespace JSC {
43
44    class MarkStack;
45
46    class EvalCodeCache {
47    public:
48        EvalExecutable* get(ExecState* exec, ScriptExecutable* owner, bool inStrictContext, const UString& evalSource, ScopeChainNode* scopeChain, JSValue& exceptionValue)
49        {
50            EvalExecutable* evalExecutable = 0;
51
52            if (!inStrictContext && evalSource.length() < maxCacheableSourceLength && (*scopeChain->begin())->isVariableObject())
53                evalExecutable = m_cacheMap.get(evalSource.impl()).get();
54
55            if (!evalExecutable) {
56                evalExecutable = EvalExecutable::create(exec, makeSource(evalSource), inStrictContext);
57                exceptionValue = evalExecutable->compile(exec, scopeChain);
58                if (exceptionValue)
59                    return 0;
60
61                if (!inStrictContext && evalSource.length() < maxCacheableSourceLength && (*scopeChain->begin())->isVariableObject() && m_cacheMap.size() < maxCacheEntries)
62                    m_cacheMap.set(evalSource.impl(), WriteBarrier<EvalExecutable>(exec->globalData(), owner, evalExecutable));
63            }
64
65            return evalExecutable;
66        }
67
68        bool isEmpty() const { return m_cacheMap.isEmpty(); }
69
70        void markAggregate(MarkStack&);
71
72    private:
73        static const unsigned maxCacheableSourceLength = 256;
74        static const int maxCacheEntries = 64;
75
76        typedef HashMap<RefPtr<StringImpl>, WriteBarrier<EvalExecutable> > EvalCacheMap;
77        EvalCacheMap m_cacheMap;
78    };
79
80} // namespace JSC
81
82#endif // EvalCodeCache_h
83