JavaScriptCore-1097.3.tar.gz

[apple/javascriptcore.git] / runtime / RegExpCachedResult.h

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+/*
+ * Copyright (C) 2012 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 INC. OR
+ * 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 RegExpCachedResult_h
+#define RegExpCachedResult_h
+
+#include "RegExpObject.h"
+
+namespace JSC {
+
+    class JSString;
+    class RegExpMatchesArray;
+
+    // RegExpCachedResult is used to track the cached results of the last
+    // match, stores on the RegExp constructor (e.g. $&, $_, $1, $2 ...).
+    // These values will be lazily generated on demand, so the cached result
+    // may be in a lazy or reified state. A lazy state is indicated by a
+    // value of m_result indicating a successful match, and a reified state
+    // is indicated by setting m_result to MatchResult::failed().
+    // Following a successful match, m_result, m_lastInput and m_lastRegExp
+    // can be used to reify the results from the match, following reification
+    // m_reifiedResult and m_reifiedInput hold the cached results.
+    class RegExpCachedResult {
+    public:
+        RegExpCachedResult(JSGlobalData& globalData, JSObject* owner, RegExp* emptyRegExp)
+            : m_result(0, 0)
+        {
+            m_lastInput.set(globalData, owner, jsEmptyString(&globalData));
+            m_lastRegExp.set(globalData, owner, emptyRegExp);
+            m_reifiedResult.clear();
+            m_reifiedInput.clear();
+        }
+
+        ALWAYS_INLINE void record(JSGlobalData& globalData, JSObject* owner, RegExp* regExp, JSString* input, MatchResult result)
+        {
+            m_lastRegExp.set(globalData, owner, regExp);
+            m_lastInput.set(globalData, owner, input);
+            m_result = result;
+        }
+
+        RegExpMatchesArray* lastResult(ExecState*, JSObject* owner);
+        void setInput(ExecState*, JSObject* owner, JSString*);
+
+        JSString* input()
+        {
+            // If m_result showas a match then we're in a lazy state, so m_lastInput
+            // is the most recent value of the input property. If not then we have
+            // reified, in which case m_reifiedInput will contain the correct value.
+            return m_result ? m_lastInput.get() : m_reifiedInput.get();
+        }
+
+        void visitChildren(SlotVisitor&);
+
+    private:
+        MatchResult m_result;
+        WriteBarrier<JSString> m_lastInput;
+        WriteBarrier<RegExp> m_lastRegExp;
+        WriteBarrier<RegExpMatchesArray> m_reifiedResult;
+        WriteBarrier<JSString> m_reifiedInput;
+    };
+
+} // namespace JSC
+
+#endif // RegExpCachedResult_h