runtime/RegExpCachedResult.h

   1 /*
   2  * Copyright (C) 2012 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  * 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. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef RegExpCachedResult_h
  27 #define RegExpCachedResult_h
  28
  29 #include "RegExpObject.h"
  30
  31 namespace JSC {
  32
  33     class JSString;
  34     class RegExpMatchesArray;
  35
  36     // RegExpCachedResult is used to track the cached results of the last
  37     // match, stores on the RegExp constructor (e.g. $&, $_, $1, $2 ...).
  38     // These values will be lazily generated on demand, so the cached result
  39     // may be in a lazy or reified state. A lazy state is indicated by a
  40     // value of m_result indicating a successful match, and a reified state
  41     // is indicated by setting m_result to MatchResult::failed().
  42     // Following a successful match, m_result, m_lastInput and m_lastRegExp
  43     // can be used to reify the results from the match, following reification
  44     // m_reifiedResult and m_reifiedInput hold the cached results.
  45     class RegExpCachedResult {
  46     public:
  47         RegExpCachedResult(JSGlobalData& globalData, JSObject* owner, RegExp* emptyRegExp)
  48             : m_result(0, 0)
  49         {
  50             m_lastInput.set(globalData, owner, jsEmptyString(&globalData));
  51             m_lastRegExp.set(globalData, owner, emptyRegExp);
  52             m_reifiedResult.clear();
  53             m_reifiedInput.clear();
  54         }
  55
  56         ALWAYS_INLINE void record(JSGlobalData& globalData, JSObject* owner, RegExp* regExp, JSString* input, MatchResult result)
  57         {
  58             m_lastRegExp.set(globalData, owner, regExp);
  59             m_lastInput.set(globalData, owner, input);
  60             m_result = result;
  61         }
  62
  63         RegExpMatchesArray* lastResult(ExecState*, JSObject* owner);
  64         void setInput(ExecState*, JSObject* owner, JSString*);
  65
  66         JSString* input()
  67         {
  68             // If m_result showas a match then we're in a lazy state, so m_lastInput
  69             // is the most recent value of the input property. If not then we have
  70             // reified, in which case m_reifiedInput will contain the correct value.
  71             return m_result ? m_lastInput.get() : m_reifiedInput.get();
  72         }
  73
  74         void visitChildren(SlotVisitor&);
  75
  76     private:
  77         MatchResult m_result;
  78         WriteBarrier<JSString> m_lastInput;
  79         WriteBarrier<RegExp> m_lastRegExp;
  80         WriteBarrier<RegExpMatchesArray> m_reifiedResult;
  81         WriteBarrier<JSString> m_reifiedInput;
  82     };
  83
  84 } // namespace JSC
  85
  86 #endif // RegExpCachedResult_h