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LibRegex: Take ownership of pattern string and fix move operations

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The Regex object created a copy of the pattern string anyways, so tweak
the constructor to allow callers to move() pattern strings into the
regex.

The Regex move constructor and assignment operator currently result in
memory corruption. The Regex object stores a Matcher object, which holds
a reference to the Regex object. So when the Regex object is moved, that
reference is no longer valid. To fix this, the reference stored in the
Matcher must be updated when the Regex is moved.
This commit is contained in:
Timothy Flynn 2021-07-29 10:21:47 -04:00 • committed by Linus Groh
parent 4a72b2c879
commit b162517065
2 changed files with 50 additions and 22 deletions
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57
Userland/Libraries/LibRegex/RegexMatcher.cpp
View file

@ -19,22 +19,45 @@ static RegexDebug s_regex_dbg(stderr);
#endif
template<class Parser>
Regex<Parser>::Regex(StringView pattern, typename ParserTraits<Parser>::OptionsType regex_options)
Regex<Parser>::Regex(String pattern, typename ParserTraits<Parser>::OptionsType regex_options)
: pattern_value(move(pattern))
{
pattern_value = pattern.to_string();
regex::Lexer lexer(pattern);
regex::Lexer lexer(pattern_value);
Parser parser(lexer, regex_options);
parser_result = parser.parse();
if (parser_result.error == regex::Error::NoError)
matcher = make<Matcher<Parser>>(*this, regex_options);
matcher = make<Matcher<Parser>>(this, regex_options);
}
template<class Parser>
Regex<Parser>::Regex(Regex&& regex)
: pattern_value(move(regex.pattern_value))
, parser_result(move(regex.parser_result))
, matcher(move(regex.matcher))
, start_offset(regex.start_offset)
{
if (matcher)
matcher->reset_pattern({}, this);
}
template<class Parser>
Regex<Parser>& Regex<Parser>::operator=(Regex&& regex)
{
pattern_value = move(regex.pattern_value);
parser_result = move(regex.parser_result);
matcher = move(regex.matcher);
if (matcher)
matcher->reset_pattern({}, this);
start_offset = regex.start_offset;
return *this;
}
template<class Parser>
typename ParserTraits<Parser>::OptionsType Regex<Parser>::options() const
{
if (parser_result.error != Error::NoError)
if (!matcher || parser_result.error != Error::NoError)
return {};
return matcher->options();
@ -71,7 +94,7 @@ RegexResult Matcher<Parser>::match(Vector<RegexStringView> const views, Optional
{
// If the pattern *itself* isn't stateful, reset any changes to start_offset.
if (!((AllFlags)m_regex_options.value() & AllFlags::Internal_Stateful))
m_pattern.start_offset = 0;
m_pattern->start_offset = 0;
size_t match_count { 0 };
@ -80,7 +103,7 @@ RegexResult Matcher<Parser>::match(Vector<RegexStringView> const views, Optional
MatchOutput output;
input.regex_options = m_regex_options | regex_options.value_or({}).value();
input.start_offset = m_pattern.start_offset;
input.start_offset = m_pattern->start_offset;
output.operations = 0;
size_t lines_to_skip = 0;
@ -107,8 +130,8 @@ RegexResult Matcher<Parser>::match(Vector<RegexStringView> const views, Optional
state.capture_group_matches.ensure_capacity(c_match_preallocation_count);
state.named_capture_group_matches.ensure_capacity(c_match_preallocation_count);
auto& capture_groups_count = m_pattern.parser_result.capture_groups_count;
auto& named_capture_groups_count = m_pattern.parser_result.named_capture_groups_count;
auto& capture_groups_count = m_pattern->parser_result.capture_groups_count;
auto& named_capture_groups_count = m_pattern->parser_result.named_capture_groups_count;
for (size_t j = 0; j < c_match_preallocation_count; ++j) {
state.matches.empend();
@ -152,11 +175,11 @@ RegexResult Matcher<Parser>::match(Vector<RegexStringView> const views, Optional
dbgln_if(REGEX_DEBUG, "[match] Starting match with view ({}): _{}_", view.length(), view);
auto view_length = view.length();
size_t view_index = m_pattern.start_offset;
size_t view_index = m_pattern->start_offset;
state.string_position = view_index;
bool succeeded = false;
if (view_index == view_length && m_pattern.parser_result.match_length_minimum == 0) {
if (view_index == view_length && m_pattern->parser_result.match_length_minimum == 0) {
// Run the code until it tries to consume something.
// This allows non-consuming code to run on empty strings, for instance
// e.g. "Exit"
@ -183,7 +206,7 @@ RegexResult Matcher<Parser>::match(Vector<RegexStringView> const views, Optional
}
for (; view_index < view_length; ++view_index) {
auto& match_length_minimum = m_pattern.parser_result.match_length_minimum;
auto& match_length_minimum = m_pattern->parser_result.match_length_minimum;
// FIXME: More performant would be to know the remaining minimum string
// length needed to match from the current position onwards within
// the vm. Add new OpCode for MinMatchLengthFromSp with the value of
@ -249,7 +272,7 @@ RegexResult Matcher<Parser>::match(Vector<RegexStringView> const views, Optional
input.global_offset += view.length() + 1; // +1 includes the line break character
if (input.regex_options.has_flag_set(AllFlags::Internal_Stateful))
m_pattern.start_offset = state.string_position;
m_pattern->start_offset = state.string_position;
if (succeeded && !continue_search)
break;
@ -262,7 +285,7 @@ RegexResult Matcher<Parser>::match(Vector<RegexStringView> const views, Optional
if (output_copy.capture_group_matches.size() < match_count)
output_copy.capture_group_matches.resize(match_count);
for (auto& matches : output_copy.capture_group_matches)
matches.resize(m_pattern.parser_result.capture_groups_count + 1);
matches.resize(m_pattern->parser_result.capture_groups_count + 1);
if (!input.regex_options.has_flag_set(AllFlags::SkipTrimEmptyMatches)) {
for (auto& matches : output_copy.capture_group_matches)
matches.template remove_all_matching([](auto& match) { return match.view.is_null(); });
@ -286,8 +309,8 @@ RegexResult Matcher<Parser>::match(Vector<RegexStringView> const views, Optional
move(output_copy.capture_group_matches),
move(output_copy.named_capture_group_matches),
output.operations,
m_pattern.parser_result.capture_groups_count,
m_pattern.parser_result.named_capture_groups_count,
m_pattern->parser_result.capture_groups_count,
m_pattern->parser_result.named_capture_groups_count,
};
}
@ -301,7 +324,7 @@ Optional<bool> Matcher<Parser>::execute(MatchInput const& input, MatchState& sta
MatchState fork_high_prio_state;
Optional<bool> success;
auto& bytecode = m_pattern.parser_result.bytecode;
auto& bytecode = m_pattern->parser_result.bytecode;
for (;;) {
++output.operations;