JavaScriptCore-521.tar.gz

[apple/javascriptcore.git] / bytecode / EvalCodeCache.h

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+/*
+ * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef EvalCodeCache_h
+#define EvalCodeCache_h
+
+#include "JSGlobalObject.h"
+#include "Nodes.h"
+#include "Parser.h"
+#include "SourceCode.h"
+#include "UString.h"
+#include <wtf/HashMap.h>
+#include <wtf/RefPtr.h>
+
+namespace JSC {
+
+    class EvalCodeCache {
+    public:
+        PassRefPtr<EvalNode> get(ExecState* exec, const UString& evalSource, ScopeChainNode* scopeChain, JSValuePtr& exceptionValue)
+        {
+            RefPtr<EvalNode> evalNode;
+
+            if (evalSource.size() < maxCacheableSourceLength && (*scopeChain->begin())->isVariableObject())
+                evalNode = m_cacheMap.get(evalSource.rep());
+
+            if (!evalNode) {
+                int errorLine;
+                UString errorMessage;
+                
+                SourceCode source = makeSource(evalSource);
+                evalNode = exec->globalData().parser->parse<EvalNode>(exec, exec->dynamicGlobalObject()->debugger(), source, &errorLine, &errorMessage);
+                if (evalNode) {
+                    if (evalSource.size() < maxCacheableSourceLength && (*scopeChain->begin())->isVariableObject() && m_cacheMap.size() < maxCacheEntries)
+                        m_cacheMap.set(evalSource.rep(), evalNode);
+                } else {
+                    exceptionValue = Error::create(exec, SyntaxError, errorMessage, errorLine, source.provider()->asID(), 0);
+                    return 0;
+                }
+            }
+
+            return evalNode.release();
+        }
+
+        bool isEmpty() const { return m_cacheMap.isEmpty(); }
+
+        void mark()
+        {
+            EvalCacheMap::iterator end = m_cacheMap.end();
+            for (EvalCacheMap::iterator ptr = m_cacheMap.begin(); ptr != end; ++ptr)
+                ptr->second->mark();
+        }
+    private:
+        static const int maxCacheableSourceLength = 256;
+        static const int maxCacheEntries = 64;
+
+        typedef HashMap<RefPtr<UString::Rep>, RefPtr<EvalNode> > EvalCacheMap;
+        EvalCacheMap m_cacheMap;
+    };
+
+} // namespace JSC
+
+#endif // EvalCodeCache_h