https://github.com/mozilla/gecko-dev
Tip revision: 1c18d06925f1faef679e20f822ecabef2be57bd7 authored by Wes Kocher on 28 February 2014, 01:08:04 UTC
Merge b2g-inbound to m-c
Merge b2g-inbound to m-c
Tip revision: 1c18d06
YarrPattern.cpp
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
*
* Copyright (C) 2009 Apple Inc. All rights reserved.
* Copyright (C) 2010 Peter Varga (pvarga@inf.u-szeged.hu), University of Szeged
*
* 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.
*/
#include "yarr/YarrPattern.h"
#include "yarr/Yarr.h"
#include "yarr/YarrCanonicalizeUCS2.h"
#include "yarr/YarrParser.h"
using namespace WTF;
namespace JSC { namespace Yarr {
#include "yarr/RegExpJitTables.h"
#if WTF_CPU_SPARC
# define BASE_FRAME_SIZE 24
#else
# define BASE_FRAME_SIZE 0
#endif
// Thanks, windows.h!
#undef min
#undef max
class CharacterClassConstructor {
public:
CharacterClassConstructor(bool isCaseInsensitive = false)
: m_isCaseInsensitive(isCaseInsensitive)
{
}
void reset()
{
m_matches.clear();
m_ranges.clear();
m_matchesUnicode.clear();
m_rangesUnicode.clear();
}
void append(const CharacterClass* other)
{
for (size_t i = 0; i < other->m_matches.size(); ++i)
addSorted(m_matches, other->m_matches[i]);
for (size_t i = 0; i < other->m_ranges.size(); ++i)
addSortedRange(m_ranges, other->m_ranges[i].begin, other->m_ranges[i].end);
for (size_t i = 0; i < other->m_matchesUnicode.size(); ++i)
addSorted(m_matchesUnicode, other->m_matchesUnicode[i]);
for (size_t i = 0; i < other->m_rangesUnicode.size(); ++i)
addSortedRange(m_rangesUnicode, other->m_rangesUnicode[i].begin, other->m_rangesUnicode[i].end);
}
void putChar(UChar ch)
{
// Handle ascii cases.
if (ch <= 0x7f) {
if (m_isCaseInsensitive && isASCIIAlpha(ch)) {
addSorted(m_matches, toASCIIUpper(ch));
addSorted(m_matches, toASCIILower(ch));
} else
addSorted(m_matches, ch);
return;
}
// Simple case, not a case-insensitive match.
if (!m_isCaseInsensitive) {
addSorted(m_matchesUnicode, ch);
return;
}
// Add multiple matches, if necessary.
const UCS2CanonicalizationRange* info = rangeInfoFor(ch);
if (info->type == CanonicalizeUnique)
addSorted(m_matchesUnicode, ch);
else
putUnicodeIgnoreCase(ch, info);
}
void putUnicodeIgnoreCase(UChar ch, const UCS2CanonicalizationRange* info)
{
ASSERT(m_isCaseInsensitive);
ASSERT(ch > 0x7f);
ASSERT(ch >= info->begin && ch <= info->end);
ASSERT(info->type != CanonicalizeUnique);
if (info->type == CanonicalizeSet) {
for (const uint16_t* set = characterSetInfo[info->value]; (ch = *set); ++set)
addSorted(m_matchesUnicode, ch);
} else {
addSorted(m_matchesUnicode, ch);
addSorted(m_matchesUnicode, getCanonicalPair(info, ch));
}
}
void putRange(UChar lo, UChar hi)
{
if (lo <= 0x7f) {
char asciiLo = lo;
char asciiHi = std::min(hi, (UChar)0x7f);
addSortedRange(m_ranges, lo, asciiHi);
if (m_isCaseInsensitive) {
if ((asciiLo <= 'Z') && (asciiHi >= 'A'))
addSortedRange(m_ranges, std::max(asciiLo, 'A')+('a'-'A'), std::min(asciiHi, 'Z')+('a'-'A'));
if ((asciiLo <= 'z') && (asciiHi >= 'a'))
addSortedRange(m_ranges, std::max(asciiLo, 'a')+('A'-'a'), std::min(asciiHi, 'z')+('A'-'a'));
}
}
if (hi <= 0x7f)
return;
lo = std::max(lo, (UChar)0x80);
addSortedRange(m_rangesUnicode, lo, hi);
if (!m_isCaseInsensitive)
return;
const UCS2CanonicalizationRange* info = rangeInfoFor(lo);
while (true) {
// Handle the range [lo .. end]
UChar end = std::min<UChar>(info->end, hi);
switch (info->type) {
case CanonicalizeUnique:
// Nothing to do - no canonical equivalents.
break;
case CanonicalizeSet: {
UChar ch;
for (const uint16_t* set = characterSetInfo[info->value]; (ch = *set); ++set)
addSorted(m_matchesUnicode, ch);
break;
}
case CanonicalizeRangeLo:
addSortedRange(m_rangesUnicode, lo + info->value, end + info->value);
break;
case CanonicalizeRangeHi:
addSortedRange(m_rangesUnicode, lo - info->value, end - info->value);
break;
case CanonicalizeAlternatingAligned:
// Use addSortedRange since there is likely an abutting range to combine with.
if (lo & 1)
addSortedRange(m_rangesUnicode, lo - 1, lo - 1);
if (!(end & 1))
addSortedRange(m_rangesUnicode, end + 1, end + 1);
break;
case CanonicalizeAlternatingUnaligned:
// Use addSortedRange since there is likely an abutting range to combine with.
if (!(lo & 1))
addSortedRange(m_rangesUnicode, lo - 1, lo - 1);
if (end & 1)
addSortedRange(m_rangesUnicode, end + 1, end + 1);
break;
}
if (hi == end)
return;
++info;
lo = info->begin;
};
}
CharacterClass* charClass()
{
CharacterClass* characterClass = js_new<CharacterClass>();
characterClass->m_matches.swap(m_matches);
characterClass->m_ranges.swap(m_ranges);
characterClass->m_matchesUnicode.swap(m_matchesUnicode);
characterClass->m_rangesUnicode.swap(m_rangesUnicode);
return characterClass;
}
private:
void addSorted(Vector<UChar>& matches, UChar ch)
{
unsigned pos = 0;
unsigned range = matches.size();
// binary chop, find position to insert char.
while (range) {
unsigned index = range >> 1;
int val = matches[pos+index] - ch;
if (!val)
return;
else if (val > 0)
range = index;
else {
pos += (index+1);
range -= (index+1);
}
}
if (pos == matches.size())
matches.append(ch);
else
matches.insert(pos, ch);
}
void addSortedRange(Vector<CharacterRange>& ranges, UChar lo, UChar hi)
{
unsigned end = ranges.size();
// Simple linear scan - I doubt there are that many ranges anyway...
// feel free to fix this with something faster (eg binary chop).
for (unsigned i = 0; i < end; ++i) {
// does the new range fall before the current position in the array
if (hi < ranges[i].begin) {
// optional optimization: concatenate appending ranges? - may not be worthwhile.
if (hi == (ranges[i].begin - 1)) {
ranges[i].begin = lo;
return;
}
ranges.insert(i, CharacterRange(lo, hi));
return;
}
// Okay, since we didn't hit the last case, the end of the new range is definitely at or after the begining
// If the new range start at or before the end of the last range, then the overlap (if it starts one after the
// end of the last range they concatenate, which is just as good.
if (lo <= (ranges[i].end + 1)) {
// found an intersect! we'll replace this entry in the array.
ranges[i].begin = std::min(ranges[i].begin, lo);
ranges[i].end = std::max(ranges[i].end, hi);
// now check if the new range can subsume any subsequent ranges.
unsigned next = i+1;
// each iteration of the loop we will either remove something from the list, or break the loop.
while (next < ranges.size()) {
if (ranges[next].begin <= (ranges[i].end + 1)) {
// the next entry now overlaps / concatenates this one.
ranges[i].end = std::max(ranges[i].end, ranges[next].end);
ranges.remove(next);
} else
break;
}
return;
}
}
// CharacterRange comes after all existing ranges.
ranges.append(CharacterRange(lo, hi));
}
bool m_isCaseInsensitive;
Vector<UChar> m_matches;
Vector<CharacterRange> m_ranges;
Vector<UChar> m_matchesUnicode;
Vector<CharacterRange> m_rangesUnicode;
};
class YarrPatternConstructor {
public:
YarrPatternConstructor(YarrPattern& pattern)
: m_pattern(pattern)
, m_characterClassConstructor(pattern.m_ignoreCase)
, m_invertParentheticalAssertion(false)
{
m_pattern.m_body = js_new<PatternDisjunction>();
m_alternative = m_pattern.m_body->addNewAlternative();
m_pattern.m_disjunctions.append(m_pattern.m_body);
}
~YarrPatternConstructor()
{
}
void reset()
{
m_pattern.reset();
m_characterClassConstructor.reset();
m_pattern.m_body = js_new<PatternDisjunction>();
m_alternative = m_pattern.m_body->addNewAlternative();
m_pattern.m_disjunctions.append(m_pattern.m_body);
}
void assertionBOL()
{
if (!m_alternative->m_terms.size() & !m_invertParentheticalAssertion) {
m_alternative->m_startsWithBOL = true;
m_alternative->m_containsBOL = true;
m_pattern.m_containsBOL = true;
}
m_alternative->m_terms.append(PatternTerm::BOL());
}
void assertionEOL()
{
m_alternative->m_terms.append(PatternTerm::EOL());
}
void assertionWordBoundary(bool invert)
{
m_alternative->m_terms.append(PatternTerm::WordBoundary(invert));
}
void atomPatternCharacter(UChar ch)
{
// We handle case-insensitive checking of unicode characters which do have both
// cases by handling them as if they were defined using a CharacterClass.
if (!m_pattern.m_ignoreCase || isASCII(ch)) {
m_alternative->m_terms.append(PatternTerm(ch));
return;
}
const UCS2CanonicalizationRange* info = rangeInfoFor(ch);
if (info->type == CanonicalizeUnique) {
m_alternative->m_terms.append(PatternTerm(ch));
return;
}
m_characterClassConstructor.putUnicodeIgnoreCase(ch, info);
CharacterClass* newCharacterClass = m_characterClassConstructor.charClass();
m_pattern.m_userCharacterClasses.append(newCharacterClass);
m_alternative->m_terms.append(PatternTerm(newCharacterClass, false));
}
void atomBuiltInCharacterClass(BuiltInCharacterClassID classID, bool invert)
{
switch (classID) {
case DigitClassID:
m_alternative->m_terms.append(PatternTerm(m_pattern.digitsCharacterClass(), invert));
break;
case SpaceClassID:
m_alternative->m_terms.append(PatternTerm(m_pattern.spacesCharacterClass(), invert));
break;
case WordClassID:
m_alternative->m_terms.append(PatternTerm(m_pattern.wordcharCharacterClass(), invert));
break;
case NewlineClassID:
m_alternative->m_terms.append(PatternTerm(m_pattern.newlineCharacterClass(), invert));
break;
}
}
void atomCharacterClassBegin(bool invert = false)
{
m_invertCharacterClass = invert;
}
void atomCharacterClassAtom(UChar ch)
{
m_characterClassConstructor.putChar(ch);
}
void atomCharacterClassRange(UChar begin, UChar end)
{
m_characterClassConstructor.putRange(begin, end);
}
void atomCharacterClassBuiltIn(BuiltInCharacterClassID classID, bool invert)
{
ASSERT(classID != NewlineClassID);
switch (classID) {
case DigitClassID:
m_characterClassConstructor.append(invert ? m_pattern.nondigitsCharacterClass() : m_pattern.digitsCharacterClass());
break;
case SpaceClassID:
m_characterClassConstructor.append(invert ? m_pattern.nonspacesCharacterClass() : m_pattern.spacesCharacterClass());
break;
case WordClassID:
m_characterClassConstructor.append(invert ? m_pattern.nonwordcharCharacterClass() : m_pattern.wordcharCharacterClass());
break;
default:
ASSERT_NOT_REACHED();
}
}
void atomCharacterClassEnd()
{
CharacterClass* newCharacterClass = m_characterClassConstructor.charClass();
m_pattern.m_userCharacterClasses.append(newCharacterClass);
m_alternative->m_terms.append(PatternTerm(newCharacterClass, m_invertCharacterClass));
}
void atomParenthesesSubpatternBegin(bool capture = true)
{
unsigned subpatternId = m_pattern.m_numSubpatterns + 1;
if (capture)
m_pattern.m_numSubpatterns++;
PatternDisjunction* parenthesesDisjunction = js_new<PatternDisjunction>(m_alternative);
m_pattern.m_disjunctions.append(parenthesesDisjunction);
m_alternative->m_terms.append(PatternTerm(PatternTerm::TypeParenthesesSubpattern, subpatternId, parenthesesDisjunction, capture, false));
m_alternative = parenthesesDisjunction->addNewAlternative();
}
void atomParentheticalAssertionBegin(bool invert = false)
{
PatternDisjunction* parenthesesDisjunction = js_new<PatternDisjunction>(m_alternative);
m_pattern.m_disjunctions.append(parenthesesDisjunction);
m_alternative->m_terms.append(PatternTerm(PatternTerm::TypeParentheticalAssertion, m_pattern.m_numSubpatterns + 1, parenthesesDisjunction, false, invert));
m_alternative = parenthesesDisjunction->addNewAlternative();
m_invertParentheticalAssertion = invert;
}
void atomParenthesesEnd()
{
ASSERT(m_alternative->m_parent);
ASSERT(m_alternative->m_parent->m_parent);
PatternDisjunction* parenthesesDisjunction = m_alternative->m_parent;
m_alternative = m_alternative->m_parent->m_parent;
PatternTerm& lastTerm = m_alternative->lastTerm();
unsigned numParenAlternatives = parenthesesDisjunction->m_alternatives.size();
unsigned numBOLAnchoredAlts = 0;
for (unsigned i = 0; i < numParenAlternatives; i++) {
// Bubble up BOL flags
if (parenthesesDisjunction->m_alternatives[i]->m_startsWithBOL)
numBOLAnchoredAlts++;
}
if (numBOLAnchoredAlts) {
m_alternative->m_containsBOL = true;
// If all the alternatives in parens start with BOL, then so does this one
if (numBOLAnchoredAlts == numParenAlternatives)
m_alternative->m_startsWithBOL = true;
}
lastTerm.parentheses.lastSubpatternId = m_pattern.m_numSubpatterns;
m_invertParentheticalAssertion = false;
}
void atomBackReference(unsigned subpatternId)
{
ASSERT(subpatternId);
m_pattern.m_containsBackreferences = true;
m_pattern.m_maxBackReference = std::max(m_pattern.m_maxBackReference, subpatternId);
if (subpatternId > m_pattern.m_numSubpatterns) {
m_alternative->m_terms.append(PatternTerm::ForwardReference());
return;
}
PatternAlternative* currentAlternative = m_alternative;
ASSERT(currentAlternative);
// Note to self: if we waited until the AST was baked, we could also remove forwards refs
while ((currentAlternative = currentAlternative->m_parent->m_parent)) {
PatternTerm& term = currentAlternative->lastTerm();
ASSERT((term.type == PatternTerm::TypeParenthesesSubpattern) || (term.type == PatternTerm::TypeParentheticalAssertion));
if ((term.type == PatternTerm::TypeParenthesesSubpattern) && term.capture() && (subpatternId == term.parentheses.subpatternId)) {
m_alternative->m_terms.append(PatternTerm::ForwardReference());
return;
}
}
m_alternative->m_terms.append(PatternTerm(subpatternId));
}
// deep copy the argument disjunction. If filterStartsWithBOL is true,
// skip alternatives with m_startsWithBOL set true.
PatternDisjunction* copyDisjunction(PatternDisjunction* disjunction, bool filterStartsWithBOL = false)
{
PatternDisjunction* newDisjunction = 0;
for (unsigned alt = 0; alt < disjunction->m_alternatives.size(); ++alt) {
PatternAlternative* alternative = disjunction->m_alternatives[alt];
if (!filterStartsWithBOL || !alternative->m_startsWithBOL) {
if (!newDisjunction) {
newDisjunction = js_new<PatternDisjunction>();
newDisjunction->m_parent = disjunction->m_parent;
}
PatternAlternative* newAlternative = newDisjunction->addNewAlternative();
newAlternative->m_terms.reserve(alternative->m_terms.size());
for (unsigned i = 0; i < alternative->m_terms.size(); ++i)
newAlternative->m_terms.append(copyTerm(alternative->m_terms[i], filterStartsWithBOL));
}
}
if (newDisjunction)
m_pattern.m_disjunctions.append(newDisjunction);
return newDisjunction;
}
PatternTerm copyTerm(PatternTerm& term, bool filterStartsWithBOL = false)
{
if ((term.type != PatternTerm::TypeParenthesesSubpattern) && (term.type != PatternTerm::TypeParentheticalAssertion))
return PatternTerm(term);
PatternTerm termCopy = term;
termCopy.parentheses.disjunction = copyDisjunction(termCopy.parentheses.disjunction, filterStartsWithBOL);
return termCopy;
}
void quantifyAtom(unsigned min, unsigned max, bool greedy)
{
ASSERT(min <= max);
ASSERT(m_alternative->m_terms.size());
if (!max) {
m_alternative->removeLastTerm();
return;
}
PatternTerm& term = m_alternative->lastTerm();
ASSERT(term.type > PatternTerm::TypeAssertionWordBoundary);
ASSERT((term.quantityCount == 1) && (term.quantityType == QuantifierFixedCount));
if (term.type == PatternTerm::TypeParentheticalAssertion) {
// If an assertion is quantified with a minimum count of zero, it can simply be removed.
// This arises from the RepeatMatcher behaviour in the spec. Matching an assertion never
// results in any input being consumed, however the continuation passed to the assertion
// (called in steps, 8c and 9 of the RepeatMatcher definition, ES5.1 15.10.2.5) will
// reject all zero length matches (see step 2.1). A match from the continuation of the
// expression will still be accepted regardless (via steps 8a and 11) - the upshot of all
// this is that matches from the assertion are not required, and won't be accepted anyway,
// so no need to ever run it.
if (!min)
m_alternative->removeLastTerm();
// We never need to run an assertion more than once. Subsequent interations will be run
// with the same start index (since assertions are non-capturing) and the same captures
// (per step 4 of RepeatMatcher in ES5.1 15.10.2.5), and as such will always produce the
// same result and captures. If the first match succeeds then the subsequent (min - 1)
// matches will too. Any additional optional matches will fail (on the same basis as the
// minimum zero quantified assertions, above), but this will still result in a match.
return;
}
if (min == 0)
term.quantify(max, greedy ? QuantifierGreedy : QuantifierNonGreedy);
else if (min == max)
term.quantify(min, QuantifierFixedCount);
else {
term.quantify(min, QuantifierFixedCount);
m_alternative->m_terms.append(copyTerm(term));
// NOTE: this term is interesting from an analysis perspective, in that it can be ignored.....
m_alternative->lastTerm().quantify((max == quantifyInfinite) ? max : max - min, greedy ? QuantifierGreedy : QuantifierNonGreedy);
if (m_alternative->lastTerm().type == PatternTerm::TypeParenthesesSubpattern)
m_alternative->lastTerm().parentheses.isCopy = true;
}
}
void disjunction()
{
m_alternative = m_alternative->m_parent->addNewAlternative();
}
ErrorCode setupAlternativeOffsets(PatternAlternative* alternative, unsigned currentCallFrameSize, unsigned initialInputPosition,
unsigned *callFrameSizeOut)
{
alternative->m_hasFixedSize = true;
Checked<unsigned> currentInputPosition = initialInputPosition;
for (unsigned i = 0; i < alternative->m_terms.size(); ++i) {
PatternTerm& term = alternative->m_terms[i];
switch (term.type) {
case PatternTerm::TypeAssertionBOL:
case PatternTerm::TypeAssertionEOL:
case PatternTerm::TypeAssertionWordBoundary:
term.inputPosition = currentInputPosition.unsafeGet();
break;
case PatternTerm::TypeBackReference:
term.inputPosition = currentInputPosition.unsafeGet();
term.frameLocation = currentCallFrameSize;
currentCallFrameSize += YarrStackSpaceForBackTrackInfoBackReference;
alternative->m_hasFixedSize = false;
break;
case PatternTerm::TypeForwardReference:
break;
case PatternTerm::TypePatternCharacter:
term.inputPosition = currentInputPosition.unsafeGet();
if (term.quantityType != QuantifierFixedCount) {
term.frameLocation = currentCallFrameSize;
currentCallFrameSize += YarrStackSpaceForBackTrackInfoPatternCharacter;
alternative->m_hasFixedSize = false;
} else
currentInputPosition += term.quantityCount;
break;
case PatternTerm::TypeCharacterClass:
term.inputPosition = currentInputPosition.unsafeGet();
if (term.quantityType != QuantifierFixedCount) {
term.frameLocation = currentCallFrameSize;
currentCallFrameSize += YarrStackSpaceForBackTrackInfoCharacterClass;
alternative->m_hasFixedSize = false;
} else
currentInputPosition += term.quantityCount;
break;
case PatternTerm::TypeParenthesesSubpattern:
// Note: for fixed once parentheses we will ensure at least the minimum is available; others are on their own.
term.frameLocation = currentCallFrameSize;
if (term.quantityCount == 1 && !term.parentheses.isCopy) {
if (term.quantityType != QuantifierFixedCount)
currentCallFrameSize += YarrStackSpaceForBackTrackInfoParenthesesOnce;
if (ErrorCode error = setupDisjunctionOffsets(term.parentheses.disjunction, currentCallFrameSize, currentInputPosition.unsafeGet(), ¤tCallFrameSize))
return error;
// If quantity is fixed, then pre-check its minimum size.
if (term.quantityType == QuantifierFixedCount)
currentInputPosition += term.parentheses.disjunction->m_minimumSize;
term.inputPosition = currentInputPosition.unsafeGet();
} else if (term.parentheses.isTerminal) {
currentCallFrameSize += YarrStackSpaceForBackTrackInfoParenthesesTerminal;
if (ErrorCode error = setupDisjunctionOffsets(term.parentheses.disjunction, currentCallFrameSize, currentInputPosition.unsafeGet(), ¤tCallFrameSize))
return error;
term.inputPosition = currentInputPosition.unsafeGet();
} else {
term.inputPosition = currentInputPosition.unsafeGet();
unsigned dummy;
if (ErrorCode error = setupDisjunctionOffsets(term.parentheses.disjunction, BASE_FRAME_SIZE, currentInputPosition.unsafeGet(), &dummy))
return error;
currentCallFrameSize += YarrStackSpaceForBackTrackInfoParentheses;
}
// Fixed count of 1 could be accepted, if they have a fixed size *AND* if all alternatives are of the same length.
alternative->m_hasFixedSize = false;
break;
case PatternTerm::TypeParentheticalAssertion:
term.inputPosition = currentInputPosition.unsafeGet();
term.frameLocation = currentCallFrameSize;
if (ErrorCode error = setupDisjunctionOffsets(term.parentheses.disjunction, currentCallFrameSize + YarrStackSpaceForBackTrackInfoParentheticalAssertion, currentInputPosition.unsafeGet(), ¤tCallFrameSize))
return error;
break;
case PatternTerm::TypeDotStarEnclosure:
alternative->m_hasFixedSize = false;
term.inputPosition = initialInputPosition;
break;
}
}
alternative->m_minimumSize = (currentInputPosition - initialInputPosition).unsafeGet();
*callFrameSizeOut = currentCallFrameSize;
return NoError;
}
ErrorCode setupDisjunctionOffsets(PatternDisjunction* disjunction, unsigned initialCallFrameSize, unsigned initialInputPosition, unsigned *maximumCallFrameSizeOut)
{
if ((disjunction != m_pattern.m_body) && (disjunction->m_alternatives.size() > 1))
initialCallFrameSize += YarrStackSpaceForBackTrackInfoAlternative;
unsigned minimumInputSize = UINT_MAX;
unsigned maximumCallFrameSize = 0;
bool hasFixedSize = true;
for (unsigned alt = 0; alt < disjunction->m_alternatives.size(); ++alt) {
PatternAlternative* alternative = disjunction->m_alternatives[alt];
unsigned currentAlternativeCallFrameSize;
if (ErrorCode error = setupAlternativeOffsets(alternative, initialCallFrameSize, initialInputPosition, ¤tAlternativeCallFrameSize))
return error;
minimumInputSize = std::min(minimumInputSize, alternative->m_minimumSize);
maximumCallFrameSize = std::max(maximumCallFrameSize, currentAlternativeCallFrameSize);
hasFixedSize &= alternative->m_hasFixedSize;
}
ASSERT(minimumInputSize != UINT_MAX);
if (minimumInputSize == UINT_MAX)
return PatternTooLarge;
ASSERT(minimumInputSize != UINT_MAX);
ASSERT(maximumCallFrameSize >= initialCallFrameSize);
disjunction->m_hasFixedSize = hasFixedSize;
disjunction->m_minimumSize = minimumInputSize;
disjunction->m_callFrameSize = maximumCallFrameSize;
*maximumCallFrameSizeOut = maximumCallFrameSize;
return NoError;
}
ErrorCode setupOffsets()
{
unsigned dummy;
return setupDisjunctionOffsets(m_pattern.m_body, BASE_FRAME_SIZE, 0, &dummy);
}
// This optimization identifies sets of parentheses that we will never need to backtrack.
// In these cases we do not need to store state from prior iterations.
// We can presently avoid backtracking for:
// * where the parens are at the end of the regular expression (last term in any of the
// alternatives of the main body disjunction).
// * where the parens are non-capturing, and quantified unbounded greedy (*).
// * where the parens do not contain any capturing subpatterns.
void checkForTerminalParentheses()
{
// This check is much too crude; should be just checking whether the candidate
// node contains nested capturing subpatterns, not the whole expression!
if (m_pattern.m_numSubpatterns)
return;
Vector<PatternAlternative*>& alternatives = m_pattern.m_body->m_alternatives;
for (size_t i = 0; i < alternatives.size(); ++i) {
Vector<PatternTerm>& terms = alternatives[i]->m_terms;
if (terms.size()) {
PatternTerm& term = terms.last();
if (term.type == PatternTerm::TypeParenthesesSubpattern
&& term.quantityType == QuantifierGreedy
&& term.quantityCount == quantifyInfinite
&& !term.capture())
term.parentheses.isTerminal = true;
}
}
}
void optimizeBOL()
{
// Look for expressions containing beginning of line (^) anchoring and unroll them.
// e.g. /^a|^b|c/ becomes /^a|^b|c/ which is executed once followed by /c/ which loops
// This code relies on the parsing code tagging alternatives with m_containsBOL and
// m_startsWithBOL and rolling those up to containing alternatives.
// At this point, this is only valid for non-multiline expressions.
PatternDisjunction* disjunction = m_pattern.m_body;
if (!m_pattern.m_containsBOL || m_pattern.m_multiline)
return;
PatternDisjunction* loopDisjunction = copyDisjunction(disjunction, true);
// Set alternatives in disjunction to "onceThrough"
for (unsigned alt = 0; alt < disjunction->m_alternatives.size(); ++alt)
disjunction->m_alternatives[alt]->setOnceThrough();
if (loopDisjunction) {
// Move alternatives from loopDisjunction to disjunction
for (unsigned alt = 0; alt < loopDisjunction->m_alternatives.size(); ++alt)
disjunction->m_alternatives.append(loopDisjunction->m_alternatives[alt]);
loopDisjunction->m_alternatives.clear();
}
}
bool containsCapturingTerms(PatternAlternative* alternative, size_t firstTermIndex, size_t lastTermIndex)
{
Vector<PatternTerm>& terms = alternative->m_terms;
for (size_t termIndex = firstTermIndex; termIndex <= lastTermIndex; ++termIndex) {
PatternTerm& term = terms[termIndex];
if (term.m_capture)
return true;
if (term.type == PatternTerm::TypeParenthesesSubpattern) {
PatternDisjunction* nestedDisjunction = term.parentheses.disjunction;
for (unsigned alt = 0; alt < nestedDisjunction->m_alternatives.size(); ++alt) {
PatternAlternative *pattern = nestedDisjunction->m_alternatives[alt];
if (pattern->m_terms.size() == 0)
continue;
if (containsCapturingTerms(pattern, 0, pattern->m_terms.size() - 1))
return true;
}
}
}
return false;
}
// This optimization identifies alternatives in the form of
// [^].*[?]<expression>.*[$] for expressions that don't have any
// capturing terms. The alternative is changed to <expression>
// followed by processing of the dot stars to find and adjust the
// beginning and the end of the match.
void optimizeDotStarWrappedExpressions()
{
Vector<PatternAlternative*>& alternatives = m_pattern.m_body->m_alternatives;
if (alternatives.size() != 1)
return;
PatternAlternative* alternative = alternatives[0];
Vector<PatternTerm>& terms = alternative->m_terms;
if (terms.size() >= 3) {
bool startsWithBOL = false;
bool endsWithEOL = false;
size_t termIndex, firstExpressionTerm, lastExpressionTerm;
termIndex = 0;
if (terms[termIndex].type == PatternTerm::TypeAssertionBOL) {
startsWithBOL = true;
++termIndex;
}
PatternTerm& firstNonAnchorTerm = terms[termIndex];
if ((firstNonAnchorTerm.type != PatternTerm::TypeCharacterClass) || (firstNonAnchorTerm.characterClass != m_pattern.newlineCharacterClass()) || !((firstNonAnchorTerm.quantityType == QuantifierGreedy) || (firstNonAnchorTerm.quantityType == QuantifierNonGreedy)))
return;
firstExpressionTerm = termIndex + 1;
termIndex = terms.size() - 1;
if (terms[termIndex].type == PatternTerm::TypeAssertionEOL) {
endsWithEOL = true;
--termIndex;
}
PatternTerm& lastNonAnchorTerm = terms[termIndex];
if ((lastNonAnchorTerm.type != PatternTerm::TypeCharacterClass) || (lastNonAnchorTerm.characterClass != m_pattern.newlineCharacterClass()) || (lastNonAnchorTerm.quantityType != QuantifierGreedy))
return;
lastExpressionTerm = termIndex - 1;
if (firstExpressionTerm > lastExpressionTerm)
return;
if (!containsCapturingTerms(alternative, firstExpressionTerm, lastExpressionTerm)) {
for (termIndex = terms.size() - 1; termIndex > lastExpressionTerm; --termIndex)
terms.remove(termIndex);
for (termIndex = firstExpressionTerm; termIndex > 0; --termIndex)
terms.remove(termIndex - 1);
terms.append(PatternTerm(startsWithBOL, endsWithEOL));
m_pattern.m_containsBOL = false;
}
}
}
private:
YarrPattern& m_pattern;
PatternAlternative* m_alternative;
CharacterClassConstructor m_characterClassConstructor;
bool m_invertCharacterClass;
bool m_invertParentheticalAssertion;
};
ErrorCode YarrPattern::compile(const String& patternString)
{
YarrPatternConstructor constructor(*this);
if (ErrorCode error = parse(constructor, patternString))
return error;
// If the pattern contains illegal backreferences reset & reparse.
// Quoting Netscape's "What's new in JavaScript 1.2",
// "Note: if the number of left parentheses is less than the number specified
// in \#, the \# is taken as an octal escape as described in the next row."
if (containsIllegalBackReference()) {
unsigned numSubpatterns = m_numSubpatterns;
constructor.reset();
#if !ASSERT_DISABLED
ErrorCode error =
#endif
parse(constructor, patternString, numSubpatterns);
ASSERT(!error);
ASSERT(numSubpatterns == m_numSubpatterns);
}
constructor.checkForTerminalParentheses();
constructor.optimizeDotStarWrappedExpressions();
constructor.optimizeBOL();
if (ErrorCode error = constructor.setupOffsets())
return error;
return NoError;
}
YarrPattern::YarrPattern(const String& pattern, bool ignoreCase, bool multiline, ErrorCode* error)
: m_ignoreCase(ignoreCase)
, m_multiline(multiline)
, m_containsBackreferences(false)
, m_containsBOL(false)
, m_numSubpatterns(0)
, m_maxBackReference(0)
, newlineCached(0)
, digitsCached(0)
, spacesCached(0)
, wordcharCached(0)
, nondigitsCached(0)
, nonspacesCached(0)
, nonwordcharCached(0)
{
*error = compile(pattern);
}
} }