1/*
2 * Copyright (C) 2012, 2016 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#pragma once
27
28#include "Heap.h"
29#include "JSObject.h"
30#include "RegExp.h"
31
32namespace JSC {
33
34class JSArray;
35class JSString;
36
37// RegExpCachedResult is used to track the cached results of the last
38// match, stores on the RegExp constructor (e.g. $&, $_, $1, $2 ...).
39// These values will be lazily generated on demand, so the cached result
40// may be in a lazy or reified state. A lazy state is indicated by a
41// value of m_result indicating a successful match, and a reified state
42// is indicated by setting m_result to MatchResult::failed().
43// Following a successful match, m_result, m_lastInput and m_lastRegExp
44// can be used to reify the results from the match, following reification
45// m_reifiedResult and m_reifiedInput hold the cached results.
46class RegExpCachedResult {
47public:
48 ALWAYS_INLINE void record(VM& vm, JSObject* owner, RegExp* regExp, JSString* input, MatchResult result)
49 {
50 vm.heap.writeBarrier(owner);
51 m_lastRegExp.setWithoutWriteBarrier(regExp);
52 m_lastInput.setWithoutWriteBarrier(input);
53 m_result = result;
54 m_reified = false;
55 }
56
57 JSArray* lastResult(ExecState*, JSObject* owner);
58 void setInput(ExecState*, JSObject* owner, JSString*);
59
60 JSString* leftContext(ExecState*, JSObject* owner);
61 JSString* rightContext(ExecState*, JSObject* owner);
62
63 JSString* input()
64 {
65 return m_reified ? m_reifiedInput.get() : m_lastInput.get();
66 }
67
68 void visitAggregate(SlotVisitor&);
69
70 // m_lastRegExp would be nullptr when RegExpCachedResult is not reified.
71 // If we find m_lastRegExp is nullptr, it means this should hold the empty RegExp.
72 static ptrdiff_t offsetOfLastRegExp() { return OBJECT_OFFSETOF(RegExpCachedResult, m_lastRegExp); }
73 static ptrdiff_t offsetOfLastInput() { return OBJECT_OFFSETOF(RegExpCachedResult, m_lastInput); }
74 static ptrdiff_t offsetOfResult() { return OBJECT_OFFSETOF(RegExpCachedResult, m_result); }
75 static ptrdiff_t offsetOfReified() { return OBJECT_OFFSETOF(RegExpCachedResult, m_reified); }
76
77private:
78 MatchResult m_result { 0, 0 };
79 bool m_reified { false };
80 WriteBarrier<JSString> m_lastInput;
81 WriteBarrier<RegExp> m_lastRegExp;
82 WriteBarrier<JSArray> m_reifiedResult;
83 WriteBarrier<JSString> m_reifiedInput;
84 WriteBarrier<JSString> m_reifiedLeftContext;
85 WriteBarrier<JSString> m_reifiedRightContext;
86};
87
88} // namespace JSC
89