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URLFilterParser.cpp
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444 lines (357 loc) · 12.9 KB
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/*
* Copyright (C) 2014, 2015 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. AND ITS CONTRIBUTORS ``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 ITS 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 "URLFilterParser.h"
#if ENABLE(CONTENT_EXTENSIONS)
#include "CombinedURLFilters.h"
#include "Term.h"
#include <JavaScriptCore/YarrParser.h>
#include <wtf/Deque.h>
#include <wtf/text/CString.h>
namespace WebCore {
namespace ContentExtensions {
class PatternParser {
public:
explicit PatternParser(bool patternIsCaseSensitive)
: m_patternIsCaseSensitive(patternIsCaseSensitive)
, m_parseStatus(URLFilterParser::Ok)
{
}
void finalize(uint64_t patternId, CombinedURLFilters& combinedURLFilters)
{
if (hasError())
return;
sinkFloatingTermIfNecessary();
simplifySunkTerms();
// Check to see if there are any terms without ? or *.
bool matchesEverything = true;
for (const auto& term : m_sunkTerms) {
if (term.matchesAtLeastOneCharacter()) {
matchesEverything = false;
break;
}
}
if (matchesEverything) {
fail(URLFilterParser::MatchesEverything);
return;
}
combinedURLFilters.addPattern(patternId, m_sunkTerms);
}
URLFilterParser::ParseStatus NODELETE parseStatus() const
{
return m_parseStatus;
}
void atomPatternCharacter(char16_t character, bool)
{
if (hasError())
return;
if (!isASCII(character)) {
fail(URLFilterParser::NonASCII);
return;
}
sinkFloatingTermIfNecessary();
ASSERT(!m_floatingTerm.isValid());
char asciiChararacter = static_cast<char>(character);
m_floatingTerm = Term(asciiChararacter, m_patternIsCaseSensitive);
}
void atomBuiltInCharacterClass(JSC::Yarr::BuiltInCharacterClassID builtInCharacterClassID, bool inverted)
{
if (hasError())
return;
sinkFloatingTermIfNecessary();
ASSERT(!m_floatingTerm.isValid());
if (builtInCharacterClassID == JSC::Yarr::BuiltInCharacterClassID::DotClassID && !inverted)
m_floatingTerm = Term(Term::UniversalTransition);
else
fail(URLFilterParser::UnsupportedCharacterClass);
}
void NODELETE quantifyAtom(unsigned minimum, unsigned maximum, bool)
{
if (hasError())
return;
ASSERT(m_floatingTerm.isValid());
if (!minimum && maximum == 1)
m_floatingTerm.quantify(AtomQuantifier::ZeroOrOne);
else if (!minimum && maximum == JSC::Yarr::quantifyInfinite)
m_floatingTerm.quantify(AtomQuantifier::ZeroOrMore);
else if (minimum == 1 && maximum == JSC::Yarr::quantifyInfinite)
m_floatingTerm.quantify(AtomQuantifier::OneOrMore);
else
fail(URLFilterParser::InvalidQuantifier);
}
void NODELETE atomBackReference(unsigned)
{
fail(URLFilterParser::BackReference);
}
void NODELETE atomNamedBackReference(const String&)
{
fail(URLFilterParser::BackReference);
}
void NODELETE atomNamedForwardReference(const String&)
{
fail(URLFilterParser::ForwardReference);
}
void NODELETE assertionBOL()
{
if (hasError())
return;
if (m_floatingTerm.isValid() || !m_sunkTerms.isEmpty() || !m_openGroups.isEmpty()) {
fail(URLFilterParser::MisplacedStartOfLine);
return;
}
m_hasBeginningOfLineAssertion = true;
}
void assertionEOL()
{
if (hasError())
return;
sinkFloatingTermIfNecessary();
ASSERT(!m_floatingTerm.isValid());
m_floatingTerm = Term(Term::EndOfLineAssertionTerm);
}
void NODELETE assertionWordBoundary(bool)
{
fail(URLFilterParser::WordBoundary);
}
void atomCharacterClassBegin(bool inverted = false)
{
if (hasError())
return;
sinkFloatingTermIfNecessary();
ASSERT(!m_floatingTerm.isValid());
m_floatingTerm = Term(Term::CharacterSetTerm, inverted);
}
void NODELETE atomCharacterClassAtom(char16_t character)
{
if (hasError())
return;
if (!isASCII(character)) {
fail(URLFilterParser::NonASCII);
return;
}
m_floatingTerm.addCharacter(character, m_patternIsCaseSensitive);
}
void NODELETE atomCharacterClassRange(char16_t a, char16_t b)
{
if (hasError())
return;
ASSERT(a);
ASSERT(b);
ASSERT(isASCII(a));
ASSERT(isASCII(b));
for (unsigned i = a; i <= b; ++i)
m_floatingTerm.addCharacter(static_cast<char16_t>(i), m_patternIsCaseSensitive);
}
void NODELETE atomClassStringDisjunction(Vector<Vector<char32_t>>)
{
fail(URLFilterParser::AtomCharacter);
}
void NODELETE atomCharacterClassSetOp(JSC::Yarr::CharacterClassSetOp)
{
// Nothing to do here.
}
void NODELETE atomCharacterClassPushNested(bool)
{
// Nothing to do here.
}
void NODELETE atomCharacterClassPopNested(bool)
{
// Nothing to do here.
}
void NODELETE atomCharacterClassEnd()
{
// Nothing to do here. The character set atom may have a quantifier, we sink the atom lazily.
}
void NODELETE atomCharacterClassBuiltIn(JSC::Yarr::BuiltInCharacterClassID, bool)
{
fail(URLFilterParser::AtomCharacter);
}
void atomParenthesesSubpatternBegin(bool = true, std::optional<String> = std::nullopt)
{
if (hasError())
return;
sinkFloatingTermIfNecessary();
m_openGroups.append(Term(Term::GroupTerm));
}
void NODELETE atomParentheticalAssertionBegin(bool, MatchDirection)
{
fail(URLFilterParser::Group);
}
void NODELETE atomParentheticalModifierBegin(OptionSet<JSC::Yarr::Flags>, OptionSet<JSC::Yarr::Flags>)
{
fail(URLFilterParser::Group);
}
void atomParenthesesEnd()
{
if (hasError())
return;
sinkFloatingTermIfNecessary();
ASSERT(!m_floatingTerm.isValid());
m_floatingTerm = m_openGroups.takeLast();
}
void NODELETE disjunction(JSC::Yarr::CreateDisjunctionPurpose)
{
fail(URLFilterParser::Disjunction);
}
NO_RETURN_DUE_TO_CRASH void resetForReparsing()
{
RELEASE_ASSERT_NOT_REACHED();
}
constexpr static bool NODELETE abortedDueToError() { return false; }
constexpr static JSC::Yarr::ErrorCode NODELETE abortErrorCode() { return JSC::Yarr::ErrorCode::NoError; }
private:
bool NODELETE hasError() const
{
return m_parseStatus != URLFilterParser::Ok;
}
void NODELETE fail(URLFilterParser::ParseStatus reason)
{
if (hasError())
return;
m_parseStatus = reason;
}
void sinkFloatingTermIfNecessary()
{
if (!m_floatingTerm.isValid())
return;
if (m_hasProcessedEndOfLineAssertion) {
fail(URLFilterParser::MisplacedEndOfLine);
m_floatingTerm = Term();
return;
}
if (m_floatingTerm.isEndOfLineAssertion())
m_hasProcessedEndOfLineAssertion = true;
if (!m_openGroups.isEmpty()) {
m_openGroups.last().extendGroupSubpattern(m_floatingTerm);
m_floatingTerm = Term();
return;
}
m_sunkTerms.append(m_floatingTerm);
m_floatingTerm = Term();
}
void simplifySunkTerms()
{
ASSERT(!m_floatingTerm.isValid());
if (m_sunkTerms.isEmpty())
return;
Term canonicalDotStar(Term::UniversalTransition);
canonicalDotStar.quantify(AtomQuantifier::ZeroOrMore);
// Replace every ".*"-like terms by our canonical version. Remove any duplicate ".*".
{
unsigned termIndex = 0;
bool isAfterDotStar = false;
while (termIndex < m_sunkTerms.size()) {
if (isAfterDotStar && m_sunkTerms[termIndex].isKnownToMatchAnyString()) {
m_sunkTerms.removeAt(termIndex);
continue;
}
isAfterDotStar = false;
if (m_sunkTerms[termIndex].isKnownToMatchAnyString()) {
m_sunkTerms[termIndex] = canonicalDotStar;
isAfterDotStar = true;
}
++termIndex;
}
}
// Add our ".*" in front if needed.
if (!m_hasBeginningOfLineAssertion && !m_sunkTerms.first().isKnownToMatchAnyString())
m_sunkTerms.insert(0, canonicalDotStar);
// Remove trailing ".*$".
if (m_sunkTerms.size() > 2 && m_sunkTerms.last().isEndOfLineAssertion() && m_sunkTerms[m_sunkTerms.size() - 2].isKnownToMatchAnyString())
m_sunkTerms.shrink(m_sunkTerms.size() - 2);
// Remove irrelevant terms that can match empty. For example in "foob?", matching "b" is irrelevant.
if (m_sunkTerms.last().isEndOfLineAssertion())
return;
while (!m_sunkTerms.isEmpty() && !m_sunkTerms.last().matchesAtLeastOneCharacter())
m_sunkTerms.removeLast();
}
const bool m_patternIsCaseSensitive;
Deque<Term> m_openGroups;
Vector<Term> m_sunkTerms;
Term m_floatingTerm;
bool m_hasBeginningOfLineAssertion { false };
bool m_hasProcessedEndOfLineAssertion { false };
URLFilterParser::ParseStatus m_parseStatus;
};
URLFilterParser::URLFilterParser(CombinedURLFilters& combinedURLFilters)
: m_combinedURLFilters(combinedURLFilters)
{
}
URLFilterParser::~URLFilterParser() = default;
URLFilterParser::ParseStatus URLFilterParser::addPattern(StringView pattern, bool patternIsCaseSensitive, uint64_t patternId)
{
if (!pattern.containsOnlyASCII())
return NonASCII;
if (pattern.isEmpty())
return EmptyPattern;
ParseStatus status = Ok;
PatternParser patternParser(patternIsCaseSensitive);
if (!JSC::Yarr::hasError(JSC::Yarr::parse(patternParser, pattern, JSC::Yarr::CompileMode::Legacy, 0, false)))
patternParser.finalize(patternId, m_combinedURLFilters);
else
status = YarrError;
if (status == Ok)
status = patternParser.parseStatus();
return status;
}
ASCIILiteral URLFilterParser::statusString(ParseStatus status)
{
switch (status) {
case Ok:
return "Ok"_s;
case MatchesEverything:
return "Matches everything."_s;
case NonASCII:
return "Only ASCII characters are supported in pattern."_s;
case UnsupportedCharacterClass:
return "Character class is not supported."_s;
case BackReference:
return "Patterns cannot contain backreferences."_s;
case ForwardReference:
return "Patterns cannot contain forward references."_s;
case MisplacedStartOfLine:
return "Start of line assertion can only appear as the first term in a filter."_s;
case WordBoundary:
return "Word boundaries assertions are not supported yet."_s;
case AtomCharacter:
return "Builtins character class atoms are not supported yet."_s;
case Group:
return "Groups are not supported yet."_s;
case Disjunction:
return "Disjunctions are not supported yet."_s;
case MisplacedEndOfLine:
return "The end of line assertion must be the last term in an expression."_s;
case EmptyPattern:
return "Empty pattern."_s;
case YarrError:
return "Internal error in YARR."_s;
case InvalidQuantifier:
return "Arbitrary atom repetitions are not supported."_s;
}
RELEASE_ASSERT_NOT_REACHED();
}
} // namespace ContentExtensions
} // namespace WebCore
#endif // ENABLE(CONTENT_EXTENSIONS)