| /* |
| * 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 "config.h" |
| #include "YarrPattern.h" |
| |
| #include "Yarr.h" |
| #include "YarrCanonicalizeUCS2.h" |
| #include "YarrParser.h" |
| #include <wtf/Vector.h> |
| |
| using namespace WTF; |
| |
| namespace JSC { namespace Yarr { |
| |
| #include "RegExpJitTables.h" |
| |
| 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. |
| UCS2CanonicalizationRange* info = rangeInfoFor(ch); |
| if (info->type == CanonicalizeUnique) |
| addSorted(m_matchesUnicode, ch); |
| else |
| putUnicodeIgnoreCase(ch, info); |
| } |
| |
| void putUnicodeIgnoreCase(UChar ch, UCS2CanonicalizationRange* info) |
| { |
| ASSERT(m_isCaseInsensitive); |
| ASSERT(ch > 0x7f); |
| ASSERT(ch >= info->begin && ch <= info->end); |
| ASSERT(info->type != CanonicalizeUnique); |
| if (info->type == CanonicalizeSet) { |
| for (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; |
| |
| 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 (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 = new CharacterClass(0); |
| |
| 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 = 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 = 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; |
| } |
| |
| 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 = 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 = 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 = new PatternDisjunction(); |
| newDisjunction->m_parent = disjunction->m_parent; |
| } |
| PatternAlternative* newAlternative = newDisjunction->addNewAlternative(); |
| 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(); |
| } |
| |
| unsigned setupAlternativeOffsets(PatternAlternative* alternative, unsigned currentCallFrameSize, unsigned initialInputPosition) |
| { |
| 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; |
| currentCallFrameSize = setupDisjunctionOffsets(term.parentheses.disjunction, currentCallFrameSize, currentInputPosition.unsafeGet()); |
| // 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; |
| currentCallFrameSize = setupDisjunctionOffsets(term.parentheses.disjunction, currentCallFrameSize, currentInputPosition.unsafeGet()); |
| term.inputPosition = currentInputPosition.unsafeGet(); |
| } else { |
| term.inputPosition = currentInputPosition.unsafeGet(); |
| setupDisjunctionOffsets(term.parentheses.disjunction, 0, currentInputPosition.unsafeGet()); |
| 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; |
| currentCallFrameSize = setupDisjunctionOffsets(term.parentheses.disjunction, currentCallFrameSize + YarrStackSpaceForBackTrackInfoParentheticalAssertion, currentInputPosition.unsafeGet()); |
| break; |
| |
| case PatternTerm::TypeDotStarEnclosure: |
| alternative->m_hasFixedSize = false; |
| term.inputPosition = initialInputPosition; |
| break; |
| } |
| } |
| |
| alternative->m_minimumSize = (currentInputPosition - initialInputPosition).unsafeGet(); |
| return currentCallFrameSize; |
| } |
| |
| unsigned setupDisjunctionOffsets(PatternDisjunction* disjunction, unsigned initialCallFrameSize, unsigned initialInputPosition) |
| { |
| 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 = setupAlternativeOffsets(alternative, initialCallFrameSize, initialInputPosition); |
| minimumInputSize = std::min(minimumInputSize, alternative->m_minimumSize); |
| maximumCallFrameSize = std::max(maximumCallFrameSize, currentAlternativeCallFrameSize); |
| hasFixedSize &= alternative->m_hasFixedSize; |
| } |
| |
| ASSERT(minimumInputSize != UINT_MAX); |
| ASSERT(maximumCallFrameSize >= initialCallFrameSize); |
| |
| disjunction->m_hasFixedSize = hasFixedSize; |
| disjunction->m_minimumSize = minimumInputSize; |
| disjunction->m_callFrameSize = maximumCallFrameSize; |
| return maximumCallFrameSize; |
| } |
| |
| void setupOffsets() |
| { |
| setupDisjunctionOffsets(m_pattern.m_body, 0, 0); |
| } |
| |
| // 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) { |
| if (containsCapturingTerms(nestedDisjunction->m_alternatives[alt], 0, nestedDisjunction->m_alternatives[alt]->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; |
| }; |
| |
| const char* YarrPattern::compile(const String& patternString) |
| { |
| YarrPatternConstructor constructor(*this); |
| |
| if (const char* 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 |
| const char* error = |
| #endif |
| parse(constructor, patternString, numSubpatterns); |
| |
| ASSERT(!error); |
| ASSERT(numSubpatterns == m_numSubpatterns); |
| } |
| |
| constructor.checkForTerminalParentheses(); |
| constructor.optimizeDotStarWrappedExpressions(); |
| constructor.optimizeBOL(); |
| |
| constructor.setupOffsets(); |
| |
| return 0; |
| } |
| |
| YarrPattern::YarrPattern(const String& pattern, bool ignoreCase, bool multiline, const char** 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); |
| } |
| |
| } } |
