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ladybird/Userland/Libraries/LibRegex/RegexParser.cpp
Timothy Flynn 8b668da9d5 LibRegex: Bail parsing class set characters upon early EOF 
Otherwise, we reach a skip() invocation at the end of this function,
which crashes due to EOF. Caught by test262.
2023-06-23 20:22:45 +02:00

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/*
* Copyright (c) 2020, Emanuel Sprung <emanuel.sprung@gmail.com>
* Copyright (c) 2020-2021, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "RegexParser.h"
#include "RegexDebug.h"
#include <AK/AnyOf.h>
#include <AK/CharacterTypes.h>
#include <AK/Debug.h>
#include <AK/DeprecatedString.h>
#include <AK/GenericLexer.h>
#include <AK/ScopeGuard.h>
#include <AK/StringBuilder.h>
#include <AK/StringUtils.h>
#include <AK/TemporaryChange.h>
#include <AK/Utf16View.h>
#include <LibUnicode/CharacterTypes.h>
namespace regex {
static constexpr size_t s_maximum_repetition_count = 1024 * 1024;
static constexpr u64 s_ecma262_maximum_repetition_count = (1ull << 53) - 1;
static constexpr auto s_alphabetic_characters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"sv;
static constexpr auto s_decimal_characters = "0123456789"sv;
static constexpr StringView identity_escape_characters(bool unicode, bool browser_extended)
{
if (unicode)
return "^$\\.*+?()[]{}|/"sv;
if (browser_extended)
return "^$\\.*+?()[|"sv;
return "^$\\.*+?()[]{}|"sv;
}
ALWAYS_INLINE bool Parser::set_error(Error error)
{
if (m_parser_state.error == Error::NoError) {
m_parser_state.error = error;
m_parser_state.error_token = m_parser_state.current_token;
}
return false; // always return false, that eases the API usage (return set_error(...)) :^)
}
ALWAYS_INLINE bool Parser::done() const
{
return match(TokenType::Eof);
}
ALWAYS_INLINE bool Parser::match(TokenType type) const
{
return m_parser_state.current_token.type() == type;
}
ALWAYS_INLINE bool Parser::match(char ch) const
{
return m_parser_state.current_token.type() == TokenType::Char && m_parser_state.current_token.value().length() == 1 && m_parser_state.current_token.value()[0] == ch;
}
ALWAYS_INLINE Token Parser::consume()
{
auto old_token = m_parser_state.current_token;
m_parser_state.current_token = m_parser_state.lexer.next();
return old_token;
}
ALWAYS_INLINE Token Parser::consume(TokenType type, Error error)
{
if (m_parser_state.current_token.type() != type) {
set_error(error);
dbgln_if(REGEX_DEBUG, "[PARSER] Error: Unexpected token {}. Expected: {}", m_parser_state.current_token.name(), Token::name(type));
}
return consume();
}
ALWAYS_INLINE bool Parser::consume(DeprecatedString const& str)
{
size_t potentially_go_back { 1 };
for (auto ch : str) {
if (match(TokenType::Char)) {
if (m_parser_state.current_token.value()[0] != ch) {
m_parser_state.lexer.back(potentially_go_back);
m_parser_state.current_token = m_parser_state.lexer.next();
return false;
}
} else {
m_parser_state.lexer.back(potentially_go_back);
m_parser_state.current_token = m_parser_state.lexer.next();
return false;
}
consume(TokenType::Char, Error::NoError);
++potentially_go_back;
}
return true;
}
ALWAYS_INLINE Optional<u32> Parser::consume_escaped_code_point(bool unicode)
{
if (match(TokenType::LeftCurly) && !unicode) {
// In non-Unicode mode, this should be parsed as a repetition symbol (repeating the 'u').
return static_cast<u32>('u');
}
m_parser_state.lexer.retreat(2 + !done()); // Go back to just before '\u' (+1 char, because we will have consumed an extra character)
if (auto code_point_or_error = m_parser_state.lexer.consume_escaped_code_point(unicode); !code_point_or_error.is_error()) {
m_parser_state.current_token = m_parser_state.lexer.next();
return code_point_or_error.value();
}
if (!unicode) {
// '\u' is allowed in non-unicode mode, just matches 'u'.
return static_cast<u32>('u');
}
set_error(Error::InvalidPattern);
return {};
}
ALWAYS_INLINE bool Parser::try_skip(StringView str)
{
if (str.starts_with(m_parser_state.current_token.value()))
str = str.substring_view(m_parser_state.current_token.value().length(), str.length() - m_parser_state.current_token.value().length());
else
return false;
size_t potentially_go_back { 0 };
for (auto ch : str) {
if (!m_parser_state.lexer.consume_specific(ch)) {
m_parser_state.lexer.back(potentially_go_back);
return false;
}
++potentially_go_back;
}
m_parser_state.current_token = m_parser_state.lexer.next();
return true;
}
ALWAYS_INLINE bool Parser::lookahead_any(StringView str)
{
return AK::any_of(str, [this](auto ch) { return match(ch); });
}
ALWAYS_INLINE unsigned char Parser::skip()
{
unsigned char ch;
if (m_parser_state.current_token.value().length() == 1) {
ch = m_parser_state.current_token.value()[0];
} else {
m_parser_state.lexer.back(m_parser_state.current_token.value().length());
ch = m_parser_state.lexer.consume();
}
m_parser_state.current_token = m_parser_state.lexer.next();
return ch;
}
ALWAYS_INLINE void Parser::back(size_t count)
{
m_parser_state.lexer.back(count);
m_parser_state.current_token = m_parser_state.lexer.next();
}
ALWAYS_INLINE void Parser::reset()
{
m_parser_state.bytecode.clear();
m_parser_state.lexer.reset();
m_parser_state.current_token = m_parser_state.lexer.next();
m_parser_state.error = Error::NoError;
m_parser_state.error_token = { TokenType::Eof, 0, {} };
m_parser_state.capture_group_minimum_lengths.clear();
m_parser_state.capture_groups_count = 0;
m_parser_state.named_capture_groups_count = 0;
m_parser_state.named_capture_groups.clear();
}
Parser::Result Parser::parse(Optional<AllOptions> regex_options)
{
reset();
if (regex_options.has_value())
m_parser_state.regex_options = regex_options.value();
if (parse_internal(m_parser_state.bytecode, m_parser_state.match_length_minimum))
consume(TokenType::Eof, Error::InvalidPattern);
else
set_error(Error::InvalidPattern);
dbgln_if(REGEX_DEBUG, "[PARSER] Produced bytecode with {} entries (opcodes + arguments)", m_parser_state.bytecode.size());
return {
move(m_parser_state.bytecode),
move(m_parser_state.capture_groups_count),
move(m_parser_state.named_capture_groups_count),
move(m_parser_state.match_length_minimum),
move(m_parser_state.error),
move(m_parser_state.error_token),
m_parser_state.named_capture_groups.keys(),
m_parser_state.regex_options,
};
}
ALWAYS_INLINE bool Parser::match_ordinary_characters()
{
// NOTE: This method must not be called during bracket and repetition parsing!
// FIXME: Add assertion for that?
auto type = m_parser_state.current_token.type();
return ((type == TokenType::Char && m_parser_state.current_token.value() != "\\"sv) // NOTE: Backslash will only be matched as 'char' if it does not form a valid escape.
|| type == TokenType::Comma
|| type == TokenType::Slash
|| type == TokenType::EqualSign
|| type == TokenType::HyphenMinus
|| type == TokenType::Colon);
}
// =============================
// Abstract Posix Parser
// =============================
ALWAYS_INLINE bool AbstractPosixParser::parse_bracket_expression(Vector<CompareTypeAndValuePair>& values, size_t& match_length_minimum)
{
for (; !done();) {
if (match(TokenType::HyphenMinus)) {
consume();
if (values.is_empty() || (values.size() == 1 && values.last().type == CharacterCompareType::Inverse)) {
// first in the bracket expression
values.append({ CharacterCompareType::Char, (ByteCodeValueType)'-' });
} else if (match(TokenType::RightBracket)) {
// Last in the bracket expression
values.append({ CharacterCompareType::Char, (ByteCodeValueType)'-' });
} else if (values.last().type == CharacterCompareType::Char) {
values.append({ CharacterCompareType::RangeExpressionDummy, 0 });
if (done())
return set_error(Error::MismatchingBracket);
if (match(TokenType::HyphenMinus)) {
consume();
// Valid range, add ordinary character
values.append({ CharacterCompareType::Char, (ByteCodeValueType)'-' });
}
} else {
return set_error(Error::InvalidRange);
}
} else if (match(TokenType::Circumflex)) {
auto t = consume();
if (values.is_empty())
values.append({ CharacterCompareType::Inverse, 0 });
else
values.append({ CharacterCompareType::Char, (ByteCodeValueType)*t.value().characters_without_null_termination() });
} else if (match(TokenType::LeftBracket)) {
consume();
if (match(TokenType::Period)) {
consume();
// FIXME: Parse collating element, this is needed when we have locale support
// This could have impact on length parameter, I guess.
set_error(Error::InvalidCollationElement);
consume(TokenType::Period, Error::InvalidCollationElement);
consume(TokenType::RightBracket, Error::MismatchingBracket);
} else if (match(TokenType::EqualSign)) {
consume();
// FIXME: Parse collating element, this is needed when we have locale support
// This could have impact on length parameter, I guess.
set_error(Error::InvalidCollationElement);
consume(TokenType::EqualSign, Error::InvalidCollationElement);
consume(TokenType::RightBracket, Error::MismatchingBracket);
} else if (match(TokenType::Colon)) {
consume();
CharClass ch_class;
// parse character class
if (match(TokenType::Char)) {
if (consume("alnum"))
ch_class = CharClass::Alnum;
else if (consume("alpha"))
ch_class = CharClass::Alpha;
else if (consume("blank"))
ch_class = CharClass::Blank;
else if (consume("cntrl"))
ch_class = CharClass::Cntrl;
else if (consume("digit"))
ch_class = CharClass::Digit;
else if (consume("graph"))
ch_class = CharClass::Graph;
else if (consume("lower"))
ch_class = CharClass::Lower;
else if (consume("print"))
ch_class = CharClass::Print;
else if (consume("punct"))
ch_class = CharClass::Punct;
else if (consume("space"))
ch_class = CharClass::Space;
else if (consume("upper"))
ch_class = CharClass::Upper;
else if (consume("xdigit"))
ch_class = CharClass::Xdigit;
else
return set_error(Error::InvalidCharacterClass);
values.append({ CharacterCompareType::CharClass, (ByteCodeValueType)ch_class });
} else
return set_error(Error::InvalidCharacterClass);
// FIXME: we do not support locale specific character classes until locales are implemented
consume(TokenType::Colon, Error::InvalidCharacterClass);
consume(TokenType::RightBracket, Error::MismatchingBracket);
} else {
return set_error(Error::MismatchingBracket);
}
} else if (match(TokenType::RightBracket)) {
if (values.is_empty() || (values.size() == 1 && values.last().type == CharacterCompareType::Inverse)) {
// handle bracket as ordinary character
values.append({ CharacterCompareType::Char, (ByteCodeValueType)*consume().value().characters_without_null_termination() });
} else {
// closing bracket expression
break;
}
} else {
values.append({ CharacterCompareType::Char, (ByteCodeValueType)skip() });
}
// check if range expression has to be completed...
if (values.size() >= 3 && values.at(values.size() - 2).type == CharacterCompareType::RangeExpressionDummy) {
if (values.last().type != CharacterCompareType::Char)
return set_error(Error::InvalidRange);
auto value2 = values.take_last();
values.take_last(); // RangeExpressionDummy
auto value1 = values.take_last();
values.append({ CharacterCompareType::CharRange, static_cast<ByteCodeValueType>(CharRange { (u32)value1.value, (u32)value2.value }) });
}
}
if (!values.is_empty()) {
match_length_minimum = 1;
if (values.first().type == CharacterCompareType::Inverse)
match_length_minimum = 0;
}
return true;
}
// =============================
// PosixBasic Parser
// =============================
bool PosixBasicParser::parse_internal(ByteCode& stack, size_t& match_length_minimum)
{
return parse_root(stack, match_length_minimum);
}
bool PosixBasicParser::parse_root(ByteCode& bytecode, size_t& match_length_minimum)
{
// basic_reg_exp : L_ANCHOR? RE_expression R_ANCHOR?
if (match(TokenType::Circumflex)) {
consume();
bytecode.empend((ByteCodeValueType)OpCodeId::CheckBegin);
}
if (!parse_re_expression(bytecode, match_length_minimum))
return false;
if (match(TokenType::Dollar)) {
consume();
bytecode.empend((ByteCodeValueType)OpCodeId::CheckEnd);
}
return !has_error();
}
bool PosixBasicParser::parse_re_expression(ByteCode& bytecode, size_t& match_length_minimum)
{
// RE_expression : RE_expression? simple_RE
while (!done()) {
if (!parse_simple_re(bytecode, match_length_minimum))
break;
}
return !has_error();
}
bool PosixBasicParser::parse_simple_re(ByteCode& bytecode, size_t& match_length_minimum)
{
// simple_RE : nondupl_RE RE_dupl_symbol?
ByteCode simple_re_bytecode;
size_t re_match_length_minimum = 0;
if (!parse_nonduplicating_re(simple_re_bytecode, re_match_length_minimum))
return false;
// RE_dupl_symbol : '*' | Back_open_brace DUP_COUNT (',' DUP_COUNT?)? Back_close_brace
if (match(TokenType::Asterisk)) {
consume();
ByteCode::transform_bytecode_repetition_any(simple_re_bytecode, true);
} else if (try_skip("\\{"sv)) {
auto read_number = [&]() -> Optional<size_t> {
if (!match(TokenType::Char))
return {};
size_t value = 0;
while (match(TokenType::Char)) {
auto c = m_parser_state.current_token.value().substring_view(0, 1);
auto c_value = c.to_uint();
if (!c_value.has_value())
break;
value *= 10;
value += *c_value;
consume();
}
return value;
};
size_t min_limit;
Optional<size_t> max_limit;
if (auto limit = read_number(); !limit.has_value())
return set_error(Error::InvalidRepetitionMarker);
else
min_limit = *limit;
if (match(TokenType::Comma)) {
consume();
max_limit = read_number();
}
if (!try_skip("\\}"sv))
return set_error(Error::MismatchingBrace);
if (max_limit.value_or(min_limit) < min_limit)
return set_error(Error::InvalidBraceContent);
if (min_limit > s_maximum_repetition_count || (max_limit.has_value() && *max_limit > s_maximum_repetition_count))
return set_error(Error::InvalidBraceContent);
auto min_repetition_mark_id = m_parser_state.repetition_mark_count++;
auto max_repetition_mark_id = m_parser_state.repetition_mark_count++;
ByteCode::transform_bytecode_repetition_min_max(simple_re_bytecode, min_limit, max_limit, min_repetition_mark_id, max_repetition_mark_id, true);
match_length_minimum += re_match_length_minimum * min_limit;
} else {
match_length_minimum += re_match_length_minimum;
}
bytecode.extend(move(simple_re_bytecode));
return true;
}
bool PosixBasicParser::parse_nonduplicating_re(ByteCode& bytecode, size_t& match_length_minimum)
{
// nondupl_RE : one_char_or_coll_elem_RE | Back_open_paren RE_expression Back_close_paren | BACKREF
if (try_skip("\\("sv)) {
TemporaryChange change { m_current_capture_group_depth, m_current_capture_group_depth + 1 };
// Max number of addressable capture groups is 10, let's just be lenient
// and accept 20; anything past that is probably a silly pattern anyway.
if (m_current_capture_group_depth > 20)
return set_error(Error::InvalidPattern);
ByteCode capture_bytecode;
size_t capture_length_minimum = 0;
auto capture_group_index = ++m_parser_state.capture_groups_count;
if (!parse_re_expression(capture_bytecode, capture_length_minimum))
return false;
if (!try_skip("\\)"sv))
return set_error(Error::MismatchingParen);
match_length_minimum += capture_length_minimum;
if (capture_group_index <= number_of_addressable_capture_groups) {
m_capture_group_minimum_lengths[capture_group_index - 1] = capture_length_minimum;
m_capture_group_seen[capture_group_index - 1] = true;
bytecode.insert_bytecode_group_capture_left(capture_group_index);
}
bytecode.extend(capture_bytecode);
if (capture_group_index <= number_of_addressable_capture_groups)
bytecode.insert_bytecode_group_capture_right(capture_group_index);
return true;
}
for (size_t i = 1; i < 10; ++i) {
char backref_name[2] { '\\', '0' };
backref_name[1] += i;
if (try_skip({ backref_name, 2 })) {
if (!m_capture_group_seen[i - 1])
return set_error(Error::InvalidNumber);
match_length_minimum += m_capture_group_minimum_lengths[i - 1];
bytecode.insert_bytecode_compare_values({ { CharacterCompareType::Reference, (ByteCodeValueType)i } });
return true;
}
}
return parse_one_char_or_collation_element(bytecode, match_length_minimum);
}
bool PosixBasicParser::parse_one_char_or_collation_element(ByteCode& bytecode, size_t& match_length_minimum)
{
// one_char_or_coll_elem_RE : ORD_CHAR | QUOTED_CHAR | '.' | bracket_expression
if (match(TokenType::Period)) {
consume();
bytecode.insert_bytecode_compare_values({ { CharacterCompareType::AnyChar, 0 } });
match_length_minimum += 1;
return true;
}
// Dollars are special if at the end of a pattern.
if (match(TokenType::Dollar)) {
consume();
// If we are at the end of a pattern, emit an end check instruction.
if (match(TokenType::Eof)) {
bytecode.empend((ByteCodeValueType)OpCodeId::CheckEnd);
return true;
}
// We are not at the end of the string, so we should roll back and continue as normal.
back(2);
}
if (match(TokenType::Char)) {
auto ch = consume().value()[0];
if (ch == '\\') {
if (m_parser_state.regex_options.has_flag_set(AllFlags::Extra))
return set_error(Error::InvalidPattern);
// This was \<ORD_CHAR>, the spec does not define any behaviour for this but glibc regex ignores it - and so do we.
return true;
}
bytecode.insert_bytecode_compare_values({ { CharacterCompareType::Char, (ByteCodeValueType)ch } });
match_length_minimum += 1;
return true;
}
// None of these are special in BRE.
if (match(TokenType::Questionmark) || match(TokenType::RightParen) || match(TokenType::HyphenMinus)
|| match(TokenType::Circumflex) || match(TokenType::RightCurly) || match(TokenType::Comma) || match(TokenType::Colon)
|| match(TokenType::Dollar) || match(TokenType::EqualSign) || match(TokenType::LeftCurly) || match(TokenType::LeftParen)
|| match(TokenType::Pipe) || match(TokenType::Slash) || match(TokenType::RightBracket) || match(TokenType::RightParen)) {
auto ch = consume().value()[0];
bytecode.insert_bytecode_compare_values({ { CharacterCompareType::Char, (ByteCodeValueType)ch } });
match_length_minimum += 1;
return true;
}
if (match(TokenType::EscapeSequence)) {
if (m_parser_state.current_token.value().is_one_of("\\)"sv, "\\}"sv, "\\("sv, "\\{"sv))
return false;
auto ch = consume().value()[1];
bytecode.insert_bytecode_compare_values({ { CharacterCompareType::Char, (ByteCodeValueType)ch } });
match_length_minimum += 1;
return true;
}
Vector<CompareTypeAndValuePair> values;
size_t bracket_minimum_length = 0;
if (match(TokenType::LeftBracket)) {
consume();
if (!AbstractPosixParser::parse_bracket_expression(values, bracket_minimum_length))
return false;
consume(TokenType::RightBracket, Error::MismatchingBracket);
if (!has_error())
bytecode.insert_bytecode_compare_values(move(values));
match_length_minimum += bracket_minimum_length;
return !has_error();
}
return set_error(Error::InvalidPattern);
}
// =============================
// PosixExtended Parser
// =============================
bool PosixExtendedParser::parse_internal(ByteCode& stack, size_t& match_length_minimum)
{
return parse_root(stack, match_length_minimum);
}
ALWAYS_INLINE bool PosixExtendedParser::match_repetition_symbol()
{
auto type = m_parser_state.current_token.type();
return (type == TokenType::Asterisk
|| type == TokenType::Plus
|| type == TokenType::Questionmark
|| type == TokenType::LeftCurly);
}
ALWAYS_INLINE bool PosixExtendedParser::parse_repetition_symbol(ByteCode& bytecode_to_repeat, size_t& match_length_minimum)
{
if (match(TokenType::LeftCurly)) {
consume();
StringBuilder number_builder;
while (match(TokenType::Char)) {
number_builder.append(consume().value());
}
auto maybe_minimum = number_builder.to_deprecated_string().to_uint();
if (!maybe_minimum.has_value())
return set_error(Error::InvalidBraceContent);
auto minimum = maybe_minimum.value();
match_length_minimum *= minimum;
if (minimum > s_maximum_repetition_count)
return set_error(Error::InvalidBraceContent);
if (match(TokenType::Comma)) {
consume();
} else {
auto repetition_mark_id = m_parser_state.repetition_mark_count++;
ByteCode bytecode;
bytecode.insert_bytecode_repetition_n(bytecode_to_repeat, minimum, repetition_mark_id);
bytecode_to_repeat = move(bytecode);
consume(TokenType::RightCurly, Error::MismatchingBrace);
return !has_error();
}
Optional<u32> maybe_maximum {};
number_builder.clear();
while (match(TokenType::Char)) {
number_builder.append(consume().value());
}
if (!number_builder.is_empty()) {
auto value = number_builder.to_deprecated_string().to_uint();
if (!value.has_value() || minimum > value.value() || *value > s_maximum_repetition_count)
return set_error(Error::InvalidBraceContent);
maybe_maximum = value.value();
}
auto min_repetition_mark_id = m_parser_state.repetition_mark_count++;
auto max_repetition_mark_id = m_parser_state.repetition_mark_count++;
ByteCode::transform_bytecode_repetition_min_max(bytecode_to_repeat, minimum, maybe_maximum, min_repetition_mark_id, max_repetition_mark_id);
consume(TokenType::RightCurly, Error::MismatchingBrace);
return !has_error();
}
if (match(TokenType::Plus)) {
consume();
bool nongreedy = match(TokenType::Questionmark);
if (nongreedy)
consume();
// Note: don't touch match_length_minimum, it's already correct
ByteCode::transform_bytecode_repetition_min_one(bytecode_to_repeat, !nongreedy);
return !has_error();
}
if (match(TokenType::Asterisk)) {
consume();
match_length_minimum = 0;
bool nongreedy = match(TokenType::Questionmark);
if (nongreedy)
consume();
ByteCode::transform_bytecode_repetition_any(bytecode_to_repeat, !nongreedy);
return !has_error();
}
if (match(TokenType::Questionmark)) {
consume();
match_length_minimum = 0;
bool nongreedy = match(TokenType::Questionmark);
if (nongreedy)
consume();
ByteCode::transform_bytecode_repetition_zero_or_one(bytecode_to_repeat, !nongreedy);
return !has_error();
}
return false;
}
ALWAYS_INLINE bool PosixExtendedParser::parse_bracket_expression(ByteCode& stack, size_t& match_length_minimum)
{
Vector<CompareTypeAndValuePair> values;
if (!AbstractPosixParser::parse_bracket_expression(values, match_length_minimum))
return false;
if (!has_error())
stack.insert_bytecode_compare_values(move(values));
return !has_error();
}
ALWAYS_INLINE bool PosixExtendedParser::parse_sub_expression(ByteCode& stack, size_t& match_length_minimum)
{
ByteCode bytecode;
size_t length = 0;
bool should_parse_repetition_symbol { false };
for (;;) {
if (match_ordinary_characters()) {
Token start_token = m_parser_state.current_token;
Token last_token = m_parser_state.current_token;
for (;;) {
if (!match_ordinary_characters())
break;
++length;
last_token = consume();
}
if (length > 1) {
// last character is inserted into 'bytecode' for duplication symbol handling
auto new_length = length - ((match_repetition_symbol() && length > 1) ? 1 : 0);
stack.insert_bytecode_compare_string({ start_token.value().characters_without_null_termination(), new_length });
}
if ((match_repetition_symbol() && length > 1) || length == 1) // Create own compare opcode for last character before duplication symbol
bytecode.insert_bytecode_compare_values({ { CharacterCompareType::Char, (ByteCodeValueType)last_token.value().characters_without_null_termination()[0] } });
should_parse_repetition_symbol = true;
break;
}
if (m_parser_state.current_token.value() == "\\"sv) {
if (m_parser_state.regex_options.has_flag_set(AllFlags::Extra))
return set_error(Error::InvalidPattern);
consume();
continue;
}
if (match_repetition_symbol())
return set_error(Error::InvalidRepetitionMarker);
if (match(TokenType::Period)) {
length = 1;
consume();
bytecode.insert_bytecode_compare_values({ { CharacterCompareType::AnyChar, 0 } });
should_parse_repetition_symbol = true;
break;
}
if (match(TokenType::EscapeSequence)) {
length = 1;
Token t = consume();
dbgln_if(REGEX_DEBUG, "[PARSER] EscapeSequence with substring {}", t.value());
bytecode.insert_bytecode_compare_values({ { CharacterCompareType::Char, (u32)t.value().characters_without_null_termination()[1] } });
should_parse_repetition_symbol = true;
break;
}
if (match(TokenType::LeftBracket)) {
consume();
ByteCode sub_ops;
if (!parse_bracket_expression(sub_ops, length) || !sub_ops.size())
return set_error(Error::InvalidBracketContent);
bytecode.extend(move(sub_ops));
consume(TokenType::RightBracket, Error::MismatchingBracket);
should_parse_repetition_symbol = true;
break;
}
if (match(TokenType::RightBracket)) {
return set_error(Error::MismatchingBracket);
}
if (match(TokenType::RightCurly)) {
return set_error(Error::MismatchingBrace);
}
if (match(TokenType::Circumflex)) {
consume();
bytecode.empend((ByteCodeValueType)OpCodeId::CheckBegin);
break;
}
if (match(TokenType::Dollar)) {
consume();
bytecode.empend((ByteCodeValueType)OpCodeId::CheckEnd);
break;
}
if (match(TokenType::RightParen))
return false;
if (match(TokenType::LeftParen)) {
enum GroupMode {
Normal,
Lookahead,
NegativeLookahead,
Lookbehind,
NegativeLookbehind,
} group_mode { Normal };
consume();
Optional<StringView> capture_group_name;
bool prevent_capture_group = false;
if (match(TokenType::Questionmark)) {
consume();
if (match(TokenType::Colon)) {
consume();
prevent_capture_group = true;
} else if (consume("<")) { // named capturing group
Token start_token = m_parser_state.current_token;
Token last_token = m_parser_state.current_token;
size_t capture_group_name_length = 0;
for (;;) {
if (!match_ordinary_characters())
return set_error(Error::InvalidNameForCaptureGroup);
if (match(TokenType::Char) && m_parser_state.current_token.value()[0] == '>') {
consume();
break;
}
++capture_group_name_length;
last_token = consume();
}
capture_group_name = StringView(start_token.value().characters_without_null_termination(), capture_group_name_length);
++m_parser_state.named_capture_groups_count;
} else if (match(TokenType::EqualSign)) { // positive lookahead
consume();
group_mode = Lookahead;
} else if (consume("!")) { // negative lookahead
group_mode = NegativeLookahead;
} else if (consume("<")) {
if (match(TokenType::EqualSign)) { // positive lookbehind
consume();
group_mode = Lookbehind;
}
if (consume("!")) // negative lookbehind
group_mode = NegativeLookbehind;
} else {
return set_error(Error::InvalidRepetitionMarker);
}
}
auto current_capture_group = m_parser_state.capture_groups_count;
if (!(m_parser_state.regex_options & AllFlags::SkipSubExprResults || prevent_capture_group)) {
bytecode.insert_bytecode_group_capture_left(current_capture_group);
m_parser_state.capture_groups_count++;
}
ByteCode capture_group_bytecode;
if (!parse_root(capture_group_bytecode, length))
return set_error(Error::InvalidPattern);
switch (group_mode) {
case Normal:
bytecode.extend(move(capture_group_bytecode));
break;
case Lookahead:
bytecode.insert_bytecode_lookaround(move(capture_group_bytecode), ByteCode::LookAroundType::LookAhead, length);
break;
case NegativeLookahead:
bytecode.insert_bytecode_lookaround(move(capture_group_bytecode), ByteCode::LookAroundType::NegatedLookAhead, length);
break;
case Lookbehind:
bytecode.insert_bytecode_lookaround(move(capture_group_bytecode), ByteCode::LookAroundType::LookBehind, length);
break;
case NegativeLookbehind:
bytecode.insert_bytecode_lookaround(move(capture_group_bytecode), ByteCode::LookAroundType::NegatedLookBehind, length);
break;
}
consume(TokenType::RightParen, Error::MismatchingParen);
if (!(m_parser_state.regex_options & AllFlags::SkipSubExprResults || prevent_capture_group)) {
if (capture_group_name.has_value())
bytecode.insert_bytecode_group_capture_right(current_capture_group, capture_group_name.value());
else
bytecode.insert_bytecode_group_capture_right(current_capture_group);
}
should_parse_repetition_symbol = true;
break;
}
return false;
}
if (match_repetition_symbol()) {
if (should_parse_repetition_symbol)
parse_repetition_symbol(bytecode, length);
else
return set_error(Error::InvalidRepetitionMarker);
}
stack.extend(move(bytecode));
match_length_minimum += length;
return true;
}
bool PosixExtendedParser::parse_root(ByteCode& stack, size_t& match_length_minimum)
{
ByteCode bytecode_left;
size_t match_length_minimum_left { 0 };
if (match_repetition_symbol())
return set_error(Error::InvalidRepetitionMarker);
for (;;) {
if (!parse_sub_expression(bytecode_left, match_length_minimum_left))
break;
if (match(TokenType::Pipe)) {
consume();
ByteCode bytecode_right;
size_t match_length_minimum_right { 0 };
if (!parse_root(bytecode_right, match_length_minimum_right) || bytecode_right.is_empty())
return set_error(Error::InvalidPattern);
ByteCode new_bytecode;
new_bytecode.insert_bytecode_alternation(move(bytecode_left), move(bytecode_right));
bytecode_left = move(new_bytecode);
match_length_minimum_left = min(match_length_minimum_right, match_length_minimum_left);
}
}
if (bytecode_left.is_empty())
set_error(Error::EmptySubExpression);
stack.extend(move(bytecode_left));
match_length_minimum = match_length_minimum_left;
return !has_error();
}
// =============================
// ECMA262 Parser
// =============================
bool ECMA262Parser::parse_internal(ByteCode& stack, size_t& match_length_minimum)
{
auto unicode = m_parser_state.regex_options.has_flag_set(AllFlags::Unicode);
auto unicode_sets = m_parser_state.regex_options.has_flag_set(AllFlags::UnicodeSets);
if (unicode || unicode_sets) {
return parse_pattern(stack, match_length_minimum, { .unicode = true, .named = true, .unicode_sets = unicode_sets });
}
ByteCode new_stack;
size_t new_match_length = 0;
auto res = parse_pattern(new_stack, new_match_length, { .unicode = false, .named = false, .unicode_sets = false });
if (m_parser_state.named_capture_groups_count > 0) {
reset();
return parse_pattern(stack, match_length_minimum, { .unicode = false, .named = true, .unicode_sets = false });
}
if (!res)
return false;
stack.extend(new_stack);
match_length_minimum = new_match_length;
return res;
}
bool ECMA262Parser::parse_pattern(ByteCode& stack, size_t& match_length_minimum, ParseFlags flags)
{
return parse_disjunction(stack, match_length_minimum, flags);
}
bool ECMA262Parser::parse_disjunction(ByteCode& stack, size_t& match_length_minimum, ParseFlags flags)
{
size_t total_match_length_minimum = NumericLimits<size_t>::max();
Vector<ByteCode> alternatives;
while (true) {
ByteCode alternative_stack;
size_t alternative_minimum_length = 0;
auto alt_ok = parse_alternative(alternative_stack, alternative_minimum_length, flags);
if (!alt_ok)
return false;
alternatives.append(move(alternative_stack));
total_match_length_minimum = min(alternative_minimum_length, total_match_length_minimum);
if (!match(TokenType::Pipe))
break;
consume();
}
Optimizer::append_alternation(stack, alternatives.span());
match_length_minimum = total_match_length_minimum;
return true;
}
bool ECMA262Parser::parse_alternative(ByteCode& stack, size_t& match_length_minimum, ParseFlags flags)
{
for (;;) {
if (match(TokenType::Eof))
return true;
if (parse_term(stack, match_length_minimum, flags))
continue;
return !has_error();
}
}
bool ECMA262Parser::parse_term(ByteCode& stack, size_t& match_length_minimum, ParseFlags flags)
{
if (parse_assertion(stack, match_length_minimum, flags))
return true;
ByteCode atom_stack;
size_t minimum_atom_length = 0;
auto parse_with_quantifier = [&] {
bool did_parse_one = false;
if (m_should_use_browser_extended_grammar)
did_parse_one = parse_extended_atom(atom_stack, minimum_atom_length, flags);
if (!did_parse_one)
did_parse_one = parse_atom(atom_stack, minimum_atom_length, flags);
if (!did_parse_one)
return false;
VERIFY(did_parse_one);
return parse_quantifier(atom_stack, minimum_atom_length, flags);
};
if (!parse_with_quantifier())
return false;
stack.extend(move(atom_stack));
match_length_minimum += minimum_atom_length;
return true;
}
bool ECMA262Parser::parse_assertion(ByteCode& stack, [[maybe_unused]] size_t& match_length_minimum, ParseFlags flags)
{
if (match(TokenType::Circumflex)) {
consume();
stack.empend((ByteCodeValueType)OpCodeId::CheckBegin);
return true;
}
if (match(TokenType::Dollar)) {
consume();
stack.empend((ByteCodeValueType)OpCodeId::CheckEnd);
return true;
}
if (try_skip("\\b"sv)) {
stack.insert_bytecode_check_boundary(BoundaryCheckType::Word);
return true;
}
if (try_skip("\\B"sv)) {
stack.insert_bytecode_check_boundary(BoundaryCheckType::NonWord);
return true;
}
if (match(TokenType::LeftParen)) {
if (!try_skip("(?"sv))
return false;
if (done()) {
set_error(Error::InvalidCaptureGroup);
return false;
}
ByteCode assertion_stack;
size_t length_dummy = 0;
bool should_parse_forward_assertion = !m_should_use_browser_extended_grammar || flags.unicode;
if (should_parse_forward_assertion && try_skip("="sv)) {
if (!parse_inner_disjunction(assertion_stack, length_dummy, flags))
return false;
stack.insert_bytecode_lookaround(move(assertion_stack), ByteCode::LookAroundType::LookAhead);
return true;
}
if (should_parse_forward_assertion && try_skip("!"sv)) {
enter_capture_group_scope();
ScopeGuard quit_scope {
[this] {
exit_capture_group_scope();
}
};
if (!parse_inner_disjunction(assertion_stack, length_dummy, flags))
return false;
stack.insert_bytecode_lookaround(move(assertion_stack), ByteCode::LookAroundType::NegatedLookAhead);
clear_all_capture_groups_in_scope(stack);
return true;
}
if (m_should_use_browser_extended_grammar) {
if (!flags.unicode) {
if (parse_quantifiable_assertion(assertion_stack, match_length_minimum, flags)) {
if (!parse_quantifier(assertion_stack, match_length_minimum, flags))
return false;
stack.extend(move(assertion_stack));
return true;
}
}
}
if (try_skip("<="sv)) {
if (!parse_inner_disjunction(assertion_stack, length_dummy, flags))
return false;
// FIXME: Somehow ensure that this assertion regexp has a fixed length.
stack.insert_bytecode_lookaround(move(assertion_stack), ByteCode::LookAroundType::LookBehind, length_dummy);
return true;
}
if (try_skip("<!"sv)) {
enter_capture_group_scope();
ScopeGuard quit_scope {
[this] {
exit_capture_group_scope();
}
};
if (!parse_inner_disjunction(assertion_stack, length_dummy, flags))
return false;
stack.insert_bytecode_lookaround(move(assertion_stack), ByteCode::LookAroundType::NegatedLookBehind, length_dummy);
clear_all_capture_groups_in_scope(stack);
return true;
}
// If none of these matched, put the '(?' back.
m_parser_state.lexer.back(3);
m_parser_state.current_token = m_parser_state.lexer.next();
return false;
}
return false;
}
bool ECMA262Parser::parse_inner_disjunction(ByteCode& bytecode_stack, size_t& length, ParseFlags flags)
{
auto disjunction_ok = parse_disjunction(bytecode_stack, length, flags);
if (!disjunction_ok)
return false;
consume(TokenType::RightParen, Error::MismatchingParen);
return true;
}
bool ECMA262Parser::parse_quantifiable_assertion(ByteCode& stack, size_t&, ParseFlags flags)
{
VERIFY(m_should_use_browser_extended_grammar);
ByteCode assertion_stack;
size_t match_length_minimum = 0;
if (try_skip("="sv)) {
if (!parse_inner_disjunction(assertion_stack, match_length_minimum, { .unicode = false, .named = flags.named, .unicode_sets = false }))
return false;
stack.insert_bytecode_lookaround(move(assertion_stack), ByteCode::LookAroundType::LookAhead);
return true;
}
if (try_skip("!"sv)) {
enter_capture_group_scope();
ScopeGuard quit_scope {
[this] {
exit_capture_group_scope();
}
};
if (!parse_inner_disjunction(assertion_stack, match_length_minimum, { .unicode = false, .named = flags.named, .unicode_sets = false }))
return false;
stack.insert_bytecode_lookaround(move(assertion_stack), ByteCode::LookAroundType::NegatedLookAhead);
clear_all_capture_groups_in_scope(stack);
return true;
}
return false;
}
StringView ECMA262Parser::read_digits_as_string(ReadDigitsInitialZeroState initial_zero, bool hex, int max_count, int min_count)
{
if (!match(TokenType::Char))
return {};
if (initial_zero == ReadDigitsInitialZeroState::Disallow && m_parser_state.current_token.value() == "0")
return {};
int count = 0;
size_t offset = 0;
auto start_token = m_parser_state.current_token;
while (match(TokenType::Char)) {
auto const c = m_parser_state.current_token.value();
if (max_count > 0 && count >= max_count)
break;
if (hex && !AK::StringUtils::convert_to_uint_from_hex(c).has_value())
break;
if (!hex && !c.to_uint().has_value())
break;
offset += consume().value().length();
++count;
}
if (count < min_count)
return {};
return StringView { start_token.value().characters_without_null_termination(), offset };
}
Optional<unsigned> ECMA262Parser::read_digits(ECMA262Parser::ReadDigitsInitialZeroState initial_zero, bool hex, int max_count, int min_count)
{
auto str = read_digits_as_string(initial_zero, hex, max_count, min_count);
if (str.is_empty())
return {};
if (hex)
return AK::StringUtils::convert_to_uint_from_hex(str);
return str.to_uint();
}
bool ECMA262Parser::parse_quantifier(ByteCode& stack, size_t& match_length_minimum, ParseFlags flags)
{
enum class Repetition {
OneOrMore,
ZeroOrMore,
Optional,
Explicit,
None,
} repetition_mark { Repetition::None };
bool ungreedy = false;
Optional<u64> repeat_min, repeat_max;
if (match(TokenType::Asterisk)) {
consume();
repetition_mark = Repetition::ZeroOrMore;
} else if (match(TokenType::Plus)) {
consume();
repetition_mark = Repetition::OneOrMore;
} else if (match(TokenType::Questionmark)) {
consume();
repetition_mark = Repetition::Optional;
} else if (match(TokenType::LeftCurly)) {
repetition_mark = Repetition::Explicit;
if (!parse_interval_quantifier(repeat_min, repeat_max)) {
if (flags.unicode) {
// Invalid interval quantifiers are disallowed in Unicode mod - they must be escaped with '\{'.
set_error(Error::InvalidPattern);
}
return !has_error();
}
} else {
return true;
}
if (match(TokenType::Questionmark)) {
consume();
ungreedy = true;
}
switch (repetition_mark) {
case Repetition::OneOrMore:
ByteCode::transform_bytecode_repetition_min_one(stack, !ungreedy);
break;
case Repetition::ZeroOrMore:
ByteCode::transform_bytecode_repetition_any(stack, !ungreedy);
match_length_minimum = 0;
break;
case Repetition::Optional:
ByteCode::transform_bytecode_repetition_zero_or_one(stack, !ungreedy);
match_length_minimum = 0;
break;
case Repetition::Explicit: {
auto min_repetition_mark_id = m_parser_state.repetition_mark_count++;
auto max_repetition_mark_id = m_parser_state.repetition_mark_count++;
ByteCode::transform_bytecode_repetition_min_max(stack, repeat_min.value(), repeat_max, min_repetition_mark_id, max_repetition_mark_id, !ungreedy);
match_length_minimum *= repeat_min.value();
break;
}
case Repetition::None:
VERIFY_NOT_REACHED();
}
return true;
}
bool ECMA262Parser::parse_interval_quantifier(Optional<u64>& repeat_min, Optional<u64>& repeat_max)
{
VERIFY(match(TokenType::LeftCurly));
consume();
auto chars_consumed = 1;
auto low_bound_string = read_digits_as_string();
chars_consumed += low_bound_string.length();
auto low_bound = low_bound_string.to_uint<u64>();
if (!low_bound.has_value()) {
if (!m_should_use_browser_extended_grammar && done())
return set_error(Error::MismatchingBrace);
back(chars_consumed + !done());
return false;
}
repeat_min = low_bound.value();
if (match(TokenType::Comma)) {
consume();
++chars_consumed;
auto high_bound_string = read_digits_as_string();
auto high_bound = high_bound_string.to_uint<u64>();
if (high_bound.has_value()) {
repeat_max = high_bound.value();
chars_consumed += high_bound_string.length();
}
} else {
repeat_max = repeat_min;
}
if (!match(TokenType::RightCurly)) {
if (!m_should_use_browser_extended_grammar && done())
return set_error(Error::MismatchingBrace);
back(chars_consumed + !done());
return false;
}
consume();
++chars_consumed;
if (repeat_max.has_value()) {
if (repeat_min.value() > repeat_max.value())
set_error(Error::InvalidBraceContent);
}
if ((*repeat_min > s_ecma262_maximum_repetition_count) || (repeat_max.has_value() && (*repeat_max > s_ecma262_maximum_repetition_count)))
return set_error(Error::InvalidBraceContent);
return true;
}
bool ECMA262Parser::parse_atom(ByteCode& stack, size_t& match_length_minimum, ParseFlags flags)
{
if (match(TokenType::EscapeSequence)) {
// Also part of AtomEscape.
auto token = consume();
match_length_minimum += 1;
stack.insert_bytecode_compare_values({ { CharacterCompareType::Char, (u8)token.value()[1] } });
return true;
}
if (try_skip("\\"sv)) {
// AtomEscape.
return parse_atom_escape(stack, match_length_minimum, flags);
}
if (match(TokenType::LeftBracket)) {
// Character class.
return parse_character_class(stack, match_length_minimum, flags);
}
if (match(TokenType::LeftParen)) {
// Non-capturing group, or a capture group.
return parse_capture_group(stack, match_length_minimum, flags);
}
if (match(TokenType::Period)) {
consume();
match_length_minimum += 1;
stack.insert_bytecode_compare_values({ { CharacterCompareType::AnyChar, 0 } });
return true;
}
if (match(TokenType::Circumflex) || match(TokenType::Dollar) || match(TokenType::RightParen)
|| match(TokenType::Pipe) || match(TokenType::Plus) || match(TokenType::Asterisk)
|| match(TokenType::Questionmark)) {
return false;
}
if (match(TokenType::RightBracket) || match(TokenType::RightCurly) || match(TokenType::LeftCurly)) {
if (flags.unicode)
return set_error(Error::InvalidPattern);
if (m_should_use_browser_extended_grammar) {
auto token = consume();
match_length_minimum += 1;
stack.insert_bytecode_compare_values({ { CharacterCompareType::Char, (u8)token.value()[0] } });
return true;
}
return false;
}
if (match_ordinary_characters()) {
auto token = consume().value();
match_length_minimum += 1;
stack.insert_bytecode_compare_values({ { CharacterCompareType::Char, (u8)token[0] } });
return true;
}
set_error(Error::InvalidPattern);
return false;
}
bool ECMA262Parser::parse_extended_atom(ByteCode&, size_t&, ParseFlags)
{
// Note: This includes only rules *not* present in parse_atom()
VERIFY(m_should_use_browser_extended_grammar);
return parse_invalid_braced_quantifier(); // FAIL FAIL FAIL
}
bool ECMA262Parser::parse_invalid_braced_quantifier()
{
if (!match(TokenType::LeftCurly))
return false;
consume();
size_t chars_consumed = 1;
auto low_bound = read_digits_as_string();
StringView high_bound;
if (low_bound.is_empty()) {
back(chars_consumed + !done());
return false;
}
chars_consumed += low_bound.length();
if (match(TokenType::Comma)) {
consume();
++chars_consumed;
high_bound = read_digits_as_string();
chars_consumed += high_bound.length();
}
if (!match(TokenType::RightCurly)) {
back(chars_consumed + !done());
return false;
}
consume();
set_error(Error::InvalidPattern);
return true;
}
bool ECMA262Parser::parse_character_escape(Vector<CompareTypeAndValuePair>& compares, size_t& match_length_minimum, ParseFlags flags)
{
// CharacterEscape > ControlEscape
if (try_skip("f"sv)) {
match_length_minimum += 1;
compares.append({ CharacterCompareType::Char, (ByteCodeValueType)'\f' });
return true;
}
if (try_skip("n"sv)) {
match_length_minimum += 1;
compares.append({ CharacterCompareType::Char, (ByteCodeValueType)'\n' });
return true;
}
if (try_skip("r"sv)) {
match_length_minimum += 1;
compares.append({ CharacterCompareType::Char, (ByteCodeValueType)'\r' });
return true;
}
if (try_skip("t"sv)) {
match_length_minimum += 1;
compares.append({ CharacterCompareType::Char, (ByteCodeValueType)'\t' });
return true;
}
if (try_skip("v"sv)) {
match_length_minimum += 1;
compares.append({ CharacterCompareType::Char, (ByteCodeValueType)'\v' });
return true;
}
// CharacterEscape > ControlLetter
if (try_skip("c"sv)) {
for (auto c : s_alphabetic_characters) {
if (try_skip({ &c, 1 })) {
match_length_minimum += 1;
compares.append({ CharacterCompareType::Char, (ByteCodeValueType)(c % 32) });
return true;
}
}
if (flags.unicode) {
set_error(Error::InvalidPattern);
return false;
}
if (m_should_use_browser_extended_grammar) {
back(1 + (done() ? 0 : 1));
compares.append({ CharacterCompareType::Char, (ByteCodeValueType)'\\' });
match_length_minimum += 1;
return true;
}
// Allow '\c' in non-unicode mode, just matches 'c'.
match_length_minimum += 1;
compares.append({ CharacterCompareType::Char, (ByteCodeValueType)'c' });
return true;
}
// '\0'
if (try_skip("0"sv)) {
if (!lookahead_any(s_decimal_characters)) {
match_length_minimum += 1;
compares.append({ CharacterCompareType::Char, (ByteCodeValueType)0 });
return true;
}
back();
}
// LegacyOctalEscapeSequence
if (m_should_use_browser_extended_grammar) {
if (!flags.unicode) {
if (auto escape = parse_legacy_octal_escape(); escape.has_value()) {
compares.append({ CharacterCompareType::Char, (ByteCodeValueType)escape.value() });
match_length_minimum += 1;
return true;
}
}
}
// HexEscape
if (try_skip("x"sv)) {
if (auto hex_escape = read_digits(ReadDigitsInitialZeroState::Allow, true, 2, 2); hex_escape.has_value()) {
match_length_minimum += 1;
compares.append({ CharacterCompareType::Char, (ByteCodeValueType)hex_escape.value() });
return true;
}
if (!flags.unicode) {
// '\x' is allowed in non-unicode mode, just matches 'x'.
match_length_minimum += 1;
compares.append({ CharacterCompareType::Char, (ByteCodeValueType)'x' });
return true;
}
set_error(Error::InvalidPattern);
return false;
}
if (try_skip("u"sv)) {
if (auto code_point = consume_escaped_code_point(flags.unicode); code_point.has_value()) {
match_length_minimum += 1;
compares.append({ CharacterCompareType::Char, (ByteCodeValueType)code_point.value() });
return true;
}
return false;
}
// IdentityEscape
for (auto ch : identity_escape_characters(flags.unicode, m_should_use_browser_extended_grammar)) {
if (try_skip({ &ch, 1 })) {
match_length_minimum += 1;
compares.append({ CharacterCompareType::Char, (ByteCodeValueType)ch });
return true;
}
}
if (flags.unicode) {
if (try_skip("/"sv)) {
match_length_minimum += 1;
compares.append({ CharacterCompareType::Char, (ByteCodeValueType)'/' });
return true;
}
}
return false;
}
bool ECMA262Parser::parse_atom_escape(ByteCode& stack, size_t& match_length_minimum, ParseFlags flags)
{
if (auto escape_str = read_digits_as_string(ReadDigitsInitialZeroState::Disallow); !escape_str.is_empty()) {
if (auto escape = escape_str.to_uint(); escape.has_value()) {
// See if this is a "back"-reference (we've already parsed the group it refers to)
auto maybe_length = m_parser_state.capture_group_minimum_lengths.get(escape.value());
if (maybe_length.has_value()) {
match_length_minimum += maybe_length.value();
stack.insert_bytecode_compare_values({ { CharacterCompareType::Reference, (ByteCodeValueType)escape.value() } });
return true;
}
// It's not a pattern seen before, so we have to see if it's a valid reference to a future group.
if (escape.value() <= ensure_total_number_of_capturing_parenthesis()) {
// This refers to a future group, and it will _always_ be matching an empty string
// So just match nothing and move on.
return true;
}
if (!m_should_use_browser_extended_grammar) {
set_error(Error::InvalidNumber);
return false;
}
}
// If not, put the characters back.
back(escape_str.length() + (done() ? 0 : 1));
}
Vector<CompareTypeAndValuePair> escape_compares;
if (parse_character_escape(escape_compares, match_length_minimum, flags)) {
stack.insert_bytecode_compare_values(move(escape_compares));
return true;
}
if (flags.named && try_skip("k"sv)) {
auto name = read_capture_group_specifier(true);
if (name.is_empty()) {
set_error(Error::InvalidNameForCaptureGroup);
return false;
}
auto maybe_capture_group = m_parser_state.named_capture_groups.get(name);
if (!maybe_capture_group.has_value()) {
set_error(Error::InvalidNameForCaptureGroup);
return false;
}
match_length_minimum += maybe_capture_group->minimum_length;
stack.insert_bytecode_compare_values({ { CharacterCompareType::Reference, (ByteCodeValueType)maybe_capture_group->group_index } });
return true;
}
if (flags.unicode) {
PropertyEscape property {};
bool negated = false;
if (parse_unicode_property_escape(property, negated)) {
Vector<CompareTypeAndValuePair> compares;
if (negated)
compares.empend(CompareTypeAndValuePair { CharacterCompareType::Inverse, 0 });
property.visit(
[&](Unicode::Property property) {
compares.empend(CompareTypeAndValuePair { CharacterCompareType::Property, (ByteCodeValueType)property });
},
[&](Unicode::GeneralCategory general_category) {
compares.empend(CompareTypeAndValuePair { CharacterCompareType::GeneralCategory, (ByteCodeValueType)general_category });
},
[&](Script script) {
if (script.is_extension)
compares.empend(CompareTypeAndValuePair { CharacterCompareType::ScriptExtension, (ByteCodeValueType)script.script });
else
compares.empend(CompareTypeAndValuePair { CharacterCompareType::Script, (ByteCodeValueType)script.script });
},
[](Empty&) { VERIFY_NOT_REACHED(); });
stack.insert_bytecode_compare_values(move(compares));
match_length_minimum += 1;
return true;
}
}
if (done())
return set_error(Error::InvalidTrailingEscape);
bool negate = false;
auto ch = parse_character_class_escape(negate);
if (!ch.has_value()) {
if (!flags.unicode) {
// Allow all SourceCharacter's as escapes here.
auto token = consume();
match_length_minimum += 1;
stack.insert_bytecode_compare_values({ { CharacterCompareType::Char, (u8)token.value()[0] } });
return true;
}
set_error(Error::InvalidCharacterClass);
return false;
}
Vector<CompareTypeAndValuePair> compares;
if (negate)
compares.empend(CompareTypeAndValuePair { CharacterCompareType::Inverse, 0 });
compares.empend(CompareTypeAndValuePair { CharacterCompareType::CharClass, (ByteCodeValueType)ch.value() });
match_length_minimum += 1;
stack.insert_bytecode_compare_values(move(compares));
return true;
}
Optional<u8> ECMA262Parser::parse_legacy_octal_escape()
{
constexpr auto all_octal_digits = "01234567"sv;
auto read_octal_digit = [&](auto start, auto end, bool should_ensure_no_following_octal_digit) -> Optional<u8> {
for (char c = '0' + start; c <= '0' + end; ++c) {
if (try_skip({ &c, 1 })) {
if (!should_ensure_no_following_octal_digit || !lookahead_any(all_octal_digits))
return c - '0';
back(2);
return {};
}
}
return {};
};
// OctalDigit(1)
if (auto digit = read_octal_digit(0, 7, true); digit.has_value()) {
return digit.value();
}
// OctalDigit(2)
if (auto left_digit = read_octal_digit(0, 3, false); left_digit.has_value()) {
if (auto right_digit = read_octal_digit(0, 7, true); right_digit.has_value()) {
return left_digit.value() * 8 + right_digit.value();
}
back(2);
}
// OctalDigit(2)
if (auto left_digit = read_octal_digit(4, 7, false); left_digit.has_value()) {
if (auto right_digit = read_octal_digit(0, 7, false); right_digit.has_value()) {
return left_digit.value() * 8 + right_digit.value();
}
back(2);
}
// OctalDigit(3)
if (auto left_digit = read_octal_digit(0, 3, false); left_digit.has_value()) {
size_t chars_consumed = 1;
if (auto mid_digit = read_octal_digit(0, 7, false); mid_digit.has_value()) {
++chars_consumed;
if (auto right_digit = read_octal_digit(0, 7, false); right_digit.has_value()) {
return left_digit.value() * 64 + mid_digit.value() * 8 + right_digit.value();
}
}
back(chars_consumed);
}
return {};
}
Optional<CharClass> ECMA262Parser::parse_character_class_escape(bool& negate, bool expect_backslash)
{
if (expect_backslash && !try_skip("\\"sv))
return {};
// CharacterClassEscape
CharClass ch_class;
if (try_skip("d"sv)) {
ch_class = CharClass::Digit;
} else if (try_skip("D"sv)) {
ch_class = CharClass::Digit;
negate = true;
} else if (try_skip("s"sv)) {
ch_class = CharClass::Space;
} else if (try_skip("S"sv)) {
ch_class = CharClass::Space;
negate = true;
} else if (try_skip("w"sv)) {
ch_class = CharClass::Word;
} else if (try_skip("W"sv)) {
ch_class = CharClass::Word;
negate = true;
} else {
return {};
}
return ch_class;
}
bool ECMA262Parser::parse_character_class(ByteCode& stack, size_t& match_length_minimum, ParseFlags flags)
{
consume(TokenType::LeftBracket, Error::InvalidPattern);
Vector<CompareTypeAndValuePair> compares;
if (match(TokenType::Circumflex)) {
// Negated charclass
consume();
compares.empend(CompareTypeAndValuePair { CharacterCompareType::Inverse, 0 });
}
// ClassContents :: [empty]
if (match(TokenType::RightBracket)) {
consume();
// Should only have at most an 'Inverse'
VERIFY(compares.size() <= 1);
stack.insert_bytecode_compare_values(move(compares));
return true;
}
// ClassContents :: [~UnicodeSetsMode] NonemptyClassRanges[?UnicodeMode]
if (!flags.unicode_sets && !parse_nonempty_class_ranges(compares, flags))
return false;
// ClassContents :: [+UnicodeSetsMode] ClassSetExpression
if (flags.unicode_sets && !parse_class_set_expression(compares))
return false;
match_length_minimum += 1;
stack.insert_bytecode_compare_values(move(compares));
return true;
}
struct CharClassRangeElement {
union {
CharClass character_class;
u32 code_point { 0 };
Unicode::Property property;
Unicode::GeneralCategory general_category;
Unicode::Script script;
};
bool is_negated { false };
bool is_character_class { false };
bool is_property { false };
bool is_general_category { false };
bool is_script { false };
bool is_script_extension { false };
};
bool ECMA262Parser::parse_nonempty_class_ranges(Vector<CompareTypeAndValuePair>& ranges, ParseFlags flags)
{
auto read_class_atom_no_dash = [&]() -> Optional<CharClassRangeElement> {
if (match(TokenType::EscapeSequence)) {
auto token = consume().value();
return { CharClassRangeElement { .code_point = (u32)token[1], .is_character_class = false } };
}
if (try_skip("\\"sv)) {
if (done()) {
set_error(Error::InvalidTrailingEscape);
return {};
}
if (try_skip("f"sv))
return { CharClassRangeElement { .code_point = '\f', .is_character_class = false } };
if (try_skip("n"sv))
return { CharClassRangeElement { .code_point = '\n', .is_character_class = false } };
if (try_skip("r"sv))
return { CharClassRangeElement { .code_point = '\r', .is_character_class = false } };
if (try_skip("t"sv))
return { CharClassRangeElement { .code_point = '\t', .is_character_class = false } };
if (try_skip("v"sv))
return { CharClassRangeElement { .code_point = '\v', .is_character_class = false } };
if (try_skip("b"sv))
return { CharClassRangeElement { .code_point = '\b', .is_character_class = false } };
if (try_skip("/"sv))
return { CharClassRangeElement { .code_point = '/', .is_character_class = false } };
// CharacterEscape > ControlLetter
if (try_skip("c"sv)) {
for (auto c : s_alphabetic_characters) {
if (try_skip({ &c, 1 })) {
return { CharClassRangeElement { .code_point = (u32)(c % 32), .is_character_class = false } };
}
}
if (flags.unicode) {
set_error(Error::InvalidPattern);
return {};
}
if (m_should_use_browser_extended_grammar) {
for (auto c = '0'; c <= '9'; ++c) {
if (try_skip({ &c, 1 }))
return { CharClassRangeElement { .code_point = (u32)(c % 32), .is_character_class = false } };
}
if (try_skip("_"sv))
return { CharClassRangeElement { .code_point = (u32)('_' % 32), .is_character_class = false } };
back(1 + !done());
return { CharClassRangeElement { .code_point = '\\', .is_character_class = false } };
}
}
// '\0'
if (try_skip("0"sv)) {
if (!lookahead_any(s_decimal_characters))
return { CharClassRangeElement { .code_point = 0, .is_character_class = false } };
back();
}
// LegacyOctalEscapeSequence
if (m_should_use_browser_extended_grammar && !flags.unicode) {
if (auto escape = parse_legacy_octal_escape(); escape.has_value())
return { CharClassRangeElement { .code_point = escape.value(), .is_character_class = false } };
}
// HexEscape
if (try_skip("x"sv)) {
if (auto hex_escape = read_digits(ReadDigitsInitialZeroState::Allow, true, 2, 2); hex_escape.has_value()) {
return { CharClassRangeElement { .code_point = hex_escape.value(), .is_character_class = false } };
} else if (!flags.unicode) {
// '\x' is allowed in non-unicode mode, just matches 'x'.
return { CharClassRangeElement { .code_point = 'x', .is_character_class = false } };
} else {
set_error(Error::InvalidPattern);
return {};
}
}
if (try_skip("u"sv)) {
if (auto code_point = consume_escaped_code_point(flags.unicode); code_point.has_value()) {
// FIXME: While code point ranges are supported, code point matches as "Char" are not!
return { CharClassRangeElement { .code_point = code_point.value(), .is_character_class = false } };
}
return {};
}
// IdentityEscape
for (auto ch : identity_escape_characters(flags.unicode, m_should_use_browser_extended_grammar)) {
if (try_skip({ &ch, 1 }))
return { CharClassRangeElement { .code_point = (u32)ch, .is_character_class = false } };
}
if (flags.unicode) {
if (try_skip("-"sv))
return { CharClassRangeElement { .code_point = '-', .is_character_class = false } };
PropertyEscape property {};
bool negated = false;
if (parse_unicode_property_escape(property, negated)) {
return property.visit(
[&](Unicode::Property property) {
return CharClassRangeElement { .property = property, .is_negated = negated, .is_character_class = true, .is_property = true };
},
[&](Unicode::GeneralCategory general_category) {
return CharClassRangeElement { .general_category = general_category, .is_negated = negated, .is_character_class = true, .is_general_category = true };
},
[&](Script script) {
if (script.is_extension)
return CharClassRangeElement { .script = script.script, .is_negated = negated, .is_character_class = true, .is_script_extension = true };
return CharClassRangeElement { .script = script.script, .is_negated = negated, .is_character_class = true, .is_script = true };
},
[](Empty&) -> CharClassRangeElement { VERIFY_NOT_REACHED(); });
}
}
if (try_skip("d"sv))
return { CharClassRangeElement { .character_class = CharClass::Digit, .is_character_class = true } };
if (try_skip("s"sv))
return { CharClassRangeElement { .character_class = CharClass::Space, .is_character_class = true } };
if (try_skip("w"sv))
return { CharClassRangeElement { .character_class = CharClass::Word, .is_character_class = true } };
if (try_skip("D"sv))
return { CharClassRangeElement { .character_class = CharClass::Digit, .is_negated = true, .is_character_class = true } };
if (try_skip("S"sv))
return { CharClassRangeElement { .character_class = CharClass::Space, .is_negated = true, .is_character_class = true } };
if (try_skip("W"sv))
return { CharClassRangeElement { .character_class = CharClass::Word, .is_negated = true, .is_character_class = true } };
if (!flags.unicode) {
// Any unrecognised escape is allowed in non-unicode mode.
return { CharClassRangeElement { .code_point = (u32)skip(), .is_character_class = false } };
}
set_error(Error::InvalidPattern);
return {};
}
if (match(TokenType::RightBracket) || match(TokenType::HyphenMinus))
return {};
// Allow any (other) SourceCharacter.
return { CharClassRangeElement { .code_point = (u32)skip(), .is_character_class = false } };
};
auto read_class_atom = [&]() -> Optional<CharClassRangeElement> {
if (match(TokenType::HyphenMinus)) {
consume();
return { CharClassRangeElement { .code_point = '-', .is_character_class = false } };
}
return read_class_atom_no_dash();
};
auto empend_atom = [&](auto& atom) {
if (atom.is_character_class) {
if (atom.is_negated)
ranges.empend(CompareTypeAndValuePair { CharacterCompareType::TemporaryInverse, 0 });
if (atom.is_property)
ranges.empend(CompareTypeAndValuePair { CharacterCompareType::Property, (ByteCodeValueType)(atom.property) });
else if (atom.is_general_category)
ranges.empend(CompareTypeAndValuePair { CharacterCompareType::GeneralCategory, (ByteCodeValueType)(atom.general_category) });
else if (atom.is_script)
ranges.empend(CompareTypeAndValuePair { CharacterCompareType::Script, (ByteCodeValueType)(atom.script) });
else if (atom.is_script_extension)
ranges.empend(CompareTypeAndValuePair { CharacterCompareType::ScriptExtension, (ByteCodeValueType)(atom.script) });
else
ranges.empend(CompareTypeAndValuePair { CharacterCompareType::CharClass, (ByteCodeValueType)atom.character_class });
} else {
VERIFY(!atom.is_negated);
ranges.empend(CompareTypeAndValuePair { CharacterCompareType::Char, atom.code_point });
}
};
while (!match(TokenType::RightBracket)) {
if (match(TokenType::Eof)) {
set_error(Error::MismatchingBracket);
return false;
}
auto first_atom = read_class_atom();
if (!first_atom.has_value())
return false;
if (match(TokenType::HyphenMinus)) {
consume();
if (match(TokenType::RightBracket)) {
// Allow '-' as the last element in a charclass, even after an atom.
m_parser_state.lexer.back(2); // -]
m_parser_state.current_token = m_parser_state.lexer.next();
goto read_as_single_atom;
}
auto second_atom = read_class_atom();
if (!second_atom.has_value())
return false;
if (first_atom.value().is_character_class || second_atom.value().is_character_class) {
if (m_should_use_browser_extended_grammar) {
if (flags.unicode) {
set_error(Error::InvalidRange);
return false;
}
// CharacterRangeOrUnion > !Unicode > CharClass
empend_atom(*first_atom);
ranges.empend(CompareTypeAndValuePair { CharacterCompareType::Char, (ByteCodeValueType)'-' });
empend_atom(*second_atom);
continue;
}
set_error(Error::InvalidRange);
return false;
}
if (first_atom.value().code_point > second_atom.value().code_point) {
set_error(Error::InvalidRange);
return false;
}
VERIFY(!first_atom.value().is_negated);
VERIFY(!second_atom.value().is_negated);
ranges.empend(CompareTypeAndValuePair { CharacterCompareType::CharRange, CharRange { first_atom.value().code_point, second_atom.value().code_point } });
continue;
}
read_as_single_atom:;
auto atom = first_atom.value();
empend_atom(atom);
}
consume(TokenType::RightBracket, Error::MismatchingBracket);
return true;
}
bool ECMA262Parser::parse_class_set_expression(Vector<CompareTypeAndValuePair>& compares)
{
auto start_position = tell();
// ClassSetExpression :: ClassUnion | ClassIntersection | ClassSubtraction
if (parse_class_subtraction(compares)) {
consume(TokenType::RightBracket, Error::MismatchingBracket);
return true;
}
if (has_error())
return false;
back(tell() - start_position + 1);
if (parse_class_intersection(compares)) {
consume(TokenType::RightBracket, Error::MismatchingBracket);
return true;
}
if (has_error())
return false;
back(tell() - start_position + 1);
if (parse_class_union(compares)) {
consume(TokenType::RightBracket, Error::MismatchingBracket);
return true;
}
return false;
}
bool ECMA262Parser::parse_class_union(Vector<regex::CompareTypeAndValuePair>& compares)
{
auto start_position = tell();
ArmedScopeGuard restore_position { [&] { back(tell() - start_position + 1); } };
auto first = true;
// ClassUnion :: ClassSetRange ClassUnion[opt] | ClassSetOperand ClassUnion[opt]
for (;;) {
if (!parse_class_set_range(compares)) {
if (has_error() || match(TokenType::RightBracket))
break;
if (!parse_class_set_operand(compares)) {
if (first || has_error())
return false;
break;
}
}
first = false;
}
restore_position.disarm();
return !has_error();
}
bool ECMA262Parser::parse_class_intersection(Vector<CompareTypeAndValuePair>& compares)
{
// ClassIntersection :: ClassSetOperand "&&" [lookahead != "&"] ClassSetOperand
// | ClassIntersection "&&" [lookahead != "&"] ClassSetOperand
Vector<CompareTypeAndValuePair> lhs;
Vector<CompareTypeAndValuePair> rhs;
auto start_position = tell();
ArmedScopeGuard restore_position { [&] { back(tell() - start_position + 1); } };
if (!parse_class_set_operand(lhs))
return false;
if (!try_skip("&&"sv))
return false;
compares.append({ CharacterCompareType::And, 0 });
compares.extend(move(lhs));
do {
rhs.clear_with_capacity();
if (!parse_class_set_operand(rhs))
return false;
compares.extend(rhs);
if (try_skip("&&&"sv))
return false;
} while (!has_error() && try_skip("&&"sv));
compares.append({ CharacterCompareType::EndAndOr, 0 });
restore_position.disarm();
return true;
}
bool ECMA262Parser::parse_class_subtraction(Vector<CompareTypeAndValuePair>& compares)
{
// ClassSubtraction :: ClassSetOperand "--" ClassSetOperand | ClassSubtraction "--" ClassSetOperand
Vector<CompareTypeAndValuePair> lhs;
Vector<CompareTypeAndValuePair> rhs;
auto start_position = tell();
ArmedScopeGuard restore_position { [&] { back(tell() - start_position + 1); } };
if (!parse_class_set_operand(lhs))
return false;
if (!try_skip("--"sv))
return false;
compares.append({ CharacterCompareType::And, 0 });
compares.extend(move(lhs));
do {
rhs.clear_with_capacity();
if (!parse_class_set_operand(rhs))
return false;
compares.append({ CharacterCompareType::TemporaryInverse, 0 });
compares.extend(rhs);
} while (!has_error() && try_skip("--"sv));
compares.append({ CharacterCompareType::EndAndOr, 0 });
restore_position.disarm();
return true;
}
bool ECMA262Parser::parse_class_set_range(Vector<CompareTypeAndValuePair>& compares)
{
// ClassSetRange :: ClassSetCharacter "-" ClassSetCharacter
auto start_position = tell();
ArmedScopeGuard restore_position { [&] { back(tell() - start_position + 1); } };
auto lhs = parse_class_set_character();
if (!lhs.has_value())
return false;
if (!match(TokenType::HyphenMinus))
return false;
consume();
auto rhs = parse_class_set_character();
if (!rhs.has_value())
return false;
compares.append({
CharacterCompareType::CharRange,
CharRange { lhs.value(), rhs.value() },
});
restore_position.disarm();
return true;
}
Optional<u32> ECMA262Parser::parse_class_set_character()
{
// ClassSetCharacter :: [lookahead ∉ ClassSetReservedDoublePunctuator] SourceCharacter but not ClassSetSyntaxCharacter
// | "\" CharacterEscape[+UnicodeMode]
// | "\" ClassSetReservedPunctuator
// | "\" b
// ClassSetReservedDoublePunctuator :: one of "&&" "!!" "##" "$$" "%%" "**" "++" ",," ".." "::" ";;" "<<" "==" ">>" "??" "@@" "^^" "``" "~~"
// ClassSetSyntaxCharacter :: one of "(" ")" "{" "}" "[" "]" "/" "-" "\" "|"
// ClassSetReservedPunctuator :: one of "&" "-" "!" "#" "%" "," ":" ";" "<" "=" ">" "@" "`" "~"
constexpr auto class_set_reserved_double_punctuator = Array {
"&&"sv, "!!"sv, "##"sv, "$$"sv, "%%"sv, "**"sv, "++"sv, ",,"sv, ".."sv, "::"sv, ";;"sv, "<<"sv, "=="sv, ">>"sv, "??"sv, "@@"sv, "^^"sv, "``"sv, "~~"sv
};
if (done()) {
set_error(Error::InvalidPattern);
return {};
}
auto start_position = tell();
ArmedScopeGuard restore { [&] { back(tell() - start_position + 1); } };
if (try_skip("\\"sv)) {
if (done()) {
set_error(Error::InvalidTrailingEscape);
return {};
}
// "\" ClassSetReservedPunctuator
for (auto const& reserved : class_set_reserved_double_punctuator) {
if (try_skip(reserved)) {
// "\" ClassSetReservedPunctuator (ClassSetReservedPunctuator)
back();
restore.disarm();
return reserved[0];
}
}
// "\" b
if (try_skip("b"sv)) {
restore.disarm();
return '\b';
}
// "\" CharacterEscape[+UnicodeMode]
Vector<CompareTypeAndValuePair> compares;
size_t minimum_length = 0;
if (parse_character_escape(compares, minimum_length, { .unicode = true })) {
VERIFY(compares.size() == 1);
auto& compare = compares.first();
VERIFY(compare.type == CharacterCompareType::Char);
restore.disarm();
return compare.value;
}
return {};
}
// [lookahead ∉ ClassSetReservedDoublePunctuator] SourceCharacter but not ClassSetSyntaxCharacter
auto lookahead_matches = any_of(class_set_reserved_double_punctuator, [this](auto& reserved) {
return try_skip(reserved);
});
if (lookahead_matches)
return {};
for (auto character : { "("sv, ")"sv, "{"sv, "}"sv, "["sv, "]"sv, "/"sv, "-"sv, "\\"sv, "|"sv }) {
if (try_skip(character))
return {};
}
restore.disarm();
return skip();
}
bool ECMA262Parser::parse_class_set_operand(Vector<regex::CompareTypeAndValuePair>& compares)
{
auto start_position = tell();
// ClassSetOperand :: ClassSetCharacter | ClassStringDisjunction | NestedClass
if (auto character = parse_class_set_character(); character.has_value()) {
compares.append({ CharacterCompareType::Char, character.value() });
return true;
}
// NestedClass :: "[" [lookahead != "^"] ClassContents[+UnicodeMode +UnicodeSetsMode] "]"
// | "[" "^" ClassContents[+UnicodeMode +UnicodeSetsMode] "]"
// | "\" CharacterClassEscape[+UnicodeMode]
if (parse_nested_class(compares))
return true;
if (has_error())
return false;
auto negated = false;
if (auto ch = parse_character_class_escape(negated, true); ch.has_value()) {
if (negated)
compares.append({ CharacterCompareType::TemporaryInverse, 1 });
compares.append({ CharacterCompareType::CharClass, (ByteCodeValueType)ch.value() });
return true;
}
PropertyEscape property {};
if (parse_unicode_property_escape(property, negated)) {
if (negated)
compares.empend(CompareTypeAndValuePair { CharacterCompareType::Inverse, 0 });
property.visit(
[&](Unicode::Property property) {
compares.empend(CompareTypeAndValuePair { CharacterCompareType::Property, (ByteCodeValueType)property });
},
[&](Unicode::GeneralCategory general_category) {
compares.empend(CompareTypeAndValuePair { CharacterCompareType::GeneralCategory, (ByteCodeValueType)general_category });
},
[&](Script script) {
if (script.is_extension)
compares.empend(CompareTypeAndValuePair { CharacterCompareType::ScriptExtension, (ByteCodeValueType)script.script });
else
compares.empend(CompareTypeAndValuePair { CharacterCompareType::Script, (ByteCodeValueType)script.script });
},
[](Empty&) { VERIFY_NOT_REACHED(); });
return true;
}
if (has_error())
return false;
// ClassStringDisjunction :: "\q{" ClassStringDisjunctionContents "}"
// ClassStringDisjunctionContents :: ClassString | ClassString "|" ClassStringDisjunctionContents
// ClassString :: [empty] | NonEmptyClassString
// NonEmptyClassString :: ClassCharacter NonEmptyClassString[opt]
if (try_skip("\\q{"sv)) {
// FIXME: Implement this :P
return set_error(Error::InvalidCharacterClass);
}
back(tell() - start_position + 1);
return false;
}
bool ECMA262Parser::parse_nested_class(Vector<regex::CompareTypeAndValuePair>& compares)
{
auto start_position = tell();
// NestedClass :: "[" [lookahead ≠ ^ ] ClassContents [+UnicodeMode, +UnicodeSetsMode] "]"
// | "[" "^" ClassContents[+UnicodeMode, +UnicodeSetsMode] "]"
// | "\" CharacterClassEscape[+UnicodeMode]
if (match(TokenType::LeftBracket)) {
consume();
compares.append(CompareTypeAndValuePair { CharacterCompareType::Or, 0 });
if (match(TokenType::Circumflex)) {
// Negated charclass
consume();
compares.empend(CompareTypeAndValuePair { CharacterCompareType::Inverse, 0 });
}
// ClassContents :: [empty]
if (match(TokenType::RightBracket)) {
consume();
// Should only have at most an 'Inverse' (after an 'Or')
VERIFY(compares.size() <= 2);
compares.append(CompareTypeAndValuePair { CharacterCompareType::EndAndOr, 0 });
return true;
}
// ClassContents :: [+UnicodeSetsMode] ClassSetExpression
if (!parse_class_set_expression(compares))
return false;
compares.append(CompareTypeAndValuePair { CharacterCompareType::EndAndOr, 0 });
return true;
}
if (try_skip("\\"sv)) {
auto negated = false;
if (auto char_class = parse_character_class_escape(negated); char_class.has_value()) {
if (negated)
compares.append({ CharacterCompareType::TemporaryInverse, 1 });
compares.append({ CharacterCompareType::CharClass, (ByteCodeValueType)char_class.value() });
return true;
}
PropertyEscape property {};
if (parse_unicode_property_escape(property, negated)) {
if (negated)
compares.empend(CompareTypeAndValuePair { CharacterCompareType::Inverse, 0 });
property.visit(
[&](Unicode::Property property) {
compares.empend(CompareTypeAndValuePair { CharacterCompareType::Property, (ByteCodeValueType)property });
},
[&](Unicode::GeneralCategory general_category) {
compares.empend(CompareTypeAndValuePair { CharacterCompareType::GeneralCategory, (ByteCodeValueType)general_category });
},
[&](Script script) {
if (script.is_extension)
compares.empend(CompareTypeAndValuePair { CharacterCompareType::ScriptExtension, (ByteCodeValueType)script.script });
else
compares.empend(CompareTypeAndValuePair { CharacterCompareType::Script, (ByteCodeValueType)script.script });
},
[](Empty&) { VERIFY_NOT_REACHED(); });
return true;
}
if (has_error())
return false;
}
back(tell() - start_position + 1);
return false;
}
bool ECMA262Parser::parse_unicode_property_escape(PropertyEscape& property, bool& negated)
{
negated = false;
if (try_skip("p"sv))
negated = false;
else if (try_skip("P"sv))
negated = true;
else
return false;
auto parsed_property = read_unicode_property_escape();
if (!parsed_property.has_value()) {
set_error(Error::InvalidNameForProperty);
return false;
}
property = move(*parsed_property);
return property.visit(
[this](Unicode::Property property) {
if (!Unicode::is_ecma262_property(property)) {
set_error(Error::InvalidNameForProperty);
return false;
}
return true;
},
[](Unicode::GeneralCategory) { return true; },
[](Script) { return true; },
[](Empty&) -> bool { VERIFY_NOT_REACHED(); });
}
DeprecatedFlyString ECMA262Parser::read_capture_group_specifier(bool take_starting_angle_bracket)
{
static auto id_start_category = Unicode::property_from_string("ID_Start"sv);
static auto id_continue_category = Unicode::property_from_string("ID_Continue"sv);
static constexpr const u32 REPLACEMENT_CHARACTER = 0xFFFD;
constexpr const u32 ZERO_WIDTH_NON_JOINER { 0x200C };
constexpr const u32 ZERO_WIDTH_JOINER { 0x200D };
if (take_starting_angle_bracket && !consume("<"))
return {};
StringBuilder builder;
auto consume_code_point = [&] {
Utf8View utf_8_view { m_parser_state.lexer.source().substring_view(m_parser_state.lexer.tell() - 1) };
if (utf_8_view.is_empty())
return REPLACEMENT_CHARACTER;
u32 code_point = *utf_8_view.begin();
auto characters = utf_8_view.byte_offset_of(1);
while (characters-- > 0)
consume();
return code_point;
};
{
// The first character is limited to: https://tc39.es/ecma262/#prod-RegExpIdentifierStart
// RegExpIdentifierStart[UnicodeMode] ::
// IdentifierStartChar
// \ RegExpUnicodeEscapeSequence[+UnicodeMode]
// [~UnicodeMode] UnicodeLeadSurrogate UnicodeTrailSurrogate
auto code_point = consume_code_point();
if (code_point == '\\' && match('u')) {
consume();
if (auto maybe_code_point = consume_escaped_code_point(true); maybe_code_point.has_value()) {
code_point = *maybe_code_point;
} else {
set_error(Error::InvalidNameForCaptureGroup);
return {};
}
}
if (is_ascii(code_point)) {
// The only valid ID_Start unicode characters in ascii are the letters.
if (!is_ascii_alpha(code_point) && code_point != '$' && code_point != '_') {
set_error(Error::InvalidNameForCaptureGroup);
return {};
}
} else if (id_start_category.has_value() && !Unicode::code_point_has_property(code_point, *id_start_category)) {
set_error(Error::InvalidNameForCaptureGroup);
return {};
}
builder.append_code_point(code_point);
}
bool hit_end = false;
// Any following characters are limited to:
// RegExpIdentifierPart[UnicodeMode] ::
// IdentifierPartChar
// \ RegExpUnicodeEscapeSequence[+UnicodeMode]
// [~UnicodeMode] UnicodeLeadSurrogate UnicodeTrailSurrogate
while (match(TokenType::Char) || match(TokenType::Dollar) || match(TokenType::LeftCurly) || match(TokenType::RightCurly)) {
auto code_point = consume_code_point();
if (code_point == '>') {
hit_end = true;
break;
}
if (code_point == '\\') {
if (!try_skip("u"sv)) {
set_error(Error::InvalidNameForCaptureGroup);
return {};
}
if (auto maybe_code_point = consume_escaped_code_point(true); maybe_code_point.has_value()) {
code_point = *maybe_code_point;
} else {
set_error(Error::InvalidNameForCaptureGroup);
return {};
}
}
if (is_ascii(code_point)) {
// The only valid ID_Continue unicode characters in ascii are the letters and numbers.
if (!is_ascii_alphanumeric(code_point) && code_point != '$' && code_point != '_') {
set_error(Error::InvalidNameForCaptureGroup);
return {};
}
} else if (code_point != ZERO_WIDTH_JOINER && code_point != ZERO_WIDTH_NON_JOINER) {
if (id_continue_category.has_value() && !Unicode::code_point_has_property(code_point, *id_continue_category)) {
set_error(Error::InvalidNameForCaptureGroup);
return {};
}
}
builder.append_code_point(code_point);
}
DeprecatedFlyString name = builder.to_deprecated_string();
if (!hit_end || name.is_empty())
set_error(Error::InvalidNameForCaptureGroup);
return name;
}
Optional<ECMA262Parser::PropertyEscape> ECMA262Parser::read_unicode_property_escape()
{
consume(TokenType::LeftCurly, Error::InvalidPattern);
auto read_until = [&]<typename... Ts>(Ts&&... terminators) {
auto start_token = m_parser_state.current_token;
size_t offset = 0;
while (match(TokenType::Char)) {
if (m_parser_state.current_token.value().is_one_of(forward<Ts>(terminators)...))
break;
offset += consume().value().length();
}
return StringView { start_token.value().characters_without_null_termination(), offset };
};
StringView property_type;
StringView property_name = read_until("="sv, "}"sv);
if (try_skip("="sv)) {
if (property_name.is_empty())
return {};
property_type = property_name;
property_name = read_until("}"sv);
}
consume(TokenType::RightCurly, Error::InvalidPattern);
if (property_type.is_empty()) {
if (auto property = Unicode::property_from_string(property_name); property.has_value())
return { *property };
if (auto general_category = Unicode::general_category_from_string(property_name); general_category.has_value())
return { *general_category };
} else if ((property_type == "General_Category"sv) || (property_type == "gc"sv)) {
if (auto general_category = Unicode::general_category_from_string(property_name); general_category.has_value())
return { *general_category };
} else if ((property_type == "Script"sv) || (property_type == "sc"sv)) {
if (auto script = Unicode::script_from_string(property_name); script.has_value())
return Script { *script, false };
} else if ((property_type == "Script_Extensions"sv) || (property_type == "scx"sv)) {
if (auto script = Unicode::script_from_string(property_name); script.has_value())
return Script { *script, true };
}
return {};
}
bool ECMA262Parser::parse_capture_group(ByteCode& stack, size_t& match_length_minimum, ParseFlags flags)
{
consume(TokenType::LeftParen, Error::InvalidPattern);
auto register_capture_group_in_current_scope = [&](auto identifier) {
m_capture_groups_in_scope.last().empend(identifier);
};
if (match(TokenType::Questionmark)) {
// Non-capturing group or group with specifier.
consume();
if (match(TokenType::Colon)) {
consume();
ByteCode noncapture_group_bytecode;
size_t length = 0;
enter_capture_group_scope();
if (!parse_disjunction(noncapture_group_bytecode, length, flags))
return set_error(Error::InvalidPattern);
clear_all_capture_groups_in_scope(stack);
exit_capture_group_scope();
consume(TokenType::RightParen, Error::MismatchingParen);
stack.extend(move(noncapture_group_bytecode));
match_length_minimum += length;
return true;
}
if (consume("<")) {
++m_parser_state.named_capture_groups_count;
auto group_index = ++m_parser_state.capture_groups_count; // Named capture groups count as normal capture groups too.
auto name = read_capture_group_specifier();
if (name.is_empty()) {
set_error(Error::InvalidNameForCaptureGroup);
return false;
}
if (m_parser_state.named_capture_groups.contains(name)) {
set_error(Error::DuplicateNamedCapture);
return false;
}
ByteCode capture_group_bytecode;
size_t length = 0;
enter_capture_group_scope();
if (!parse_disjunction(capture_group_bytecode, length, flags))
return set_error(Error::InvalidPattern);
clear_all_capture_groups_in_scope(stack);
exit_capture_group_scope();
register_capture_group_in_current_scope(group_index);
consume(TokenType::RightParen, Error::MismatchingParen);
stack.insert_bytecode_group_capture_left(group_index);
stack.extend(move(capture_group_bytecode));
stack.insert_bytecode_group_capture_right(group_index, name.view());
match_length_minimum += length;
m_parser_state.capture_group_minimum_lengths.set(group_index, length);
m_parser_state.named_capture_groups.set(name, { group_index, length });
return true;
}
set_error(Error::InvalidCaptureGroup);
return false;
}
auto group_index = ++m_parser_state.capture_groups_count;
enter_capture_group_scope();
ByteCode capture_group_bytecode;
size_t length = 0;
if (!parse_disjunction(capture_group_bytecode, length, flags))
return set_error(Error::InvalidPattern);
clear_all_capture_groups_in_scope(stack);
exit_capture_group_scope();
register_capture_group_in_current_scope(group_index);
stack.insert_bytecode_group_capture_left(group_index);
stack.extend(move(capture_group_bytecode));
m_parser_state.capture_group_minimum_lengths.set(group_index, length);
consume(TokenType::RightParen, Error::MismatchingParen);
stack.insert_bytecode_group_capture_right(group_index);
match_length_minimum += length;
return true;
}
size_t ECMA262Parser::ensure_total_number_of_capturing_parenthesis()
{
if (m_total_number_of_capturing_parenthesis.has_value())
return m_total_number_of_capturing_parenthesis.value();
GenericLexer lexer { m_parser_state.lexer.source() };
size_t count = 0;
while (!lexer.is_eof()) {
switch (lexer.peek()) {
case '\\':
lexer.consume(min(lexer.tell_remaining(), 2));
continue;
case '[':
while (!lexer.is_eof()) {
if (lexer.consume_specific('\\')) {
if (lexer.is_eof())
break;
lexer.consume();
continue;
}
if (lexer.consume_specific(']')) {
break;
}
if (lexer.is_eof())
break;
lexer.consume();
}
break;
case '(':
lexer.consume();
if (lexer.consume_specific('?')) {
// non-capturing group '(?:', lookaround '(?<='/'(?<!', or named capture '(?<'
if (!lexer.consume_specific('<'))
break;
if (lexer.next_is(is_any_of("=!"sv)))
break;
++count;
} else {
++count;
}
break;
default:
lexer.consume();
break;
}
}
m_total_number_of_capturing_parenthesis = count;
return count;
}
}
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