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LibRegex+LibJS: Combine named and unnamed capture groups in MatchState

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Combining these into one list helps reduce the size of MatchState, and
as a result, reduces the amount of memory consumed during execution of
very large regex matches.

Doing this also allows us to remove a few regex byte code instructions:
ClearNamedCaptureGroup, SaveLeftNamedCaptureGroup, and NamedReference.
Named groups now behave the same as unnamed groups for these operations.
Note that SaveRightNamedCaptureGroup still exists to cache the matched
group name.

This also removes the recursion level from the MatchState, as it can
exist as a local variable in Matcher::execute instead.
This commit is contained in:
Timothy Flynn 2021-08-14 16:28:54 -04:00 • committed by Linus Groh
parent fea181bde3
commit f1ce998d73
9 changed files with 69 additions and 202 deletions
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80
Userland/Libraries/LibRegex/RegexByteCode.cpp
View file

@ -166,18 +166,12 @@ void ByteCode::ensure_opcodes_initialized()
case OpCodeId::ClearCaptureGroup:
s_opcodes[i] = make<OpCode_ClearCaptureGroup>();
break;
case OpCodeId::ClearNamedCaptureGroup:
s_opcodes[i] = make<OpCode_ClearNamedCaptureGroup>();
break;
case OpCodeId::SaveLeftCaptureGroup:
s_opcodes[i] = make<OpCode_SaveLeftCaptureGroup>();
break;
case OpCodeId::SaveRightCaptureGroup:
s_opcodes[i] = make<OpCode_SaveRightCaptureGroup>();
break;
case OpCodeId::SaveLeftNamedCaptureGroup:
s_opcodes[i] = make<OpCode_SaveLeftNamedCaptureGroup>();
break;
case OpCodeId::SaveRightNamedCaptureGroup:
s_opcodes[i] = make<OpCode_SaveRightNamedCaptureGroup>();
break;
@ -378,52 +372,26 @@ ALWAYS_INLINE ExecutionResult OpCode_SaveRightCaptureGroup::execute(MatchInput c
return ExecutionResult::Continue;
}
ALWAYS_INLINE ExecutionResult OpCode_ClearNamedCaptureGroup::execute(MatchInput const& input, MatchState& state, MatchOutput&) const
{
if (input.match_index < state.capture_group_matches.size()) {
auto& group = state.named_capture_group_matches[input.match_index];
if (auto it = group.find(name()); it != group.end())
it->value.reset();
}
return ExecutionResult::Continue;
}
ALWAYS_INLINE ExecutionResult OpCode_SaveLeftNamedCaptureGroup::execute(MatchInput const& input, MatchState& state, MatchOutput&) const
{
if (input.match_index >= state.named_capture_group_matches.size()) {
state.named_capture_group_matches.ensure_capacity(input.match_index);
auto capacity = state.named_capture_group_matches.capacity();
for (size_t i = state.named_capture_group_matches.size(); i <= capacity; ++i)
state.named_capture_group_matches.empend();
}
state.named_capture_group_matches.at(input.match_index).ensure(name()).column = state.string_position;
return ExecutionResult::Continue;
}
ALWAYS_INLINE ExecutionResult OpCode_SaveRightNamedCaptureGroup::execute(MatchInput const& input, MatchState& state, MatchOutput&) const
{
StringView capture_group_name = name();
auto& match = state.capture_group_matches.at(input.match_index).at(id());
auto start_position = match.left_column;
if (state.string_position < start_position)
return ExecutionResult::Failed_ExecuteLowPrioForks;
if (state.named_capture_group_matches.at(input.match_index).contains(capture_group_name)) {
auto start_position = state.named_capture_group_matches.at(input.match_index).ensure(capture_group_name).column;
auto length = state.string_position - start_position;
auto length = state.string_position - start_position;
auto& map = state.named_capture_group_matches.at(input.match_index);
if (start_position < match.column)
return ExecutionResult::Continue;
if constexpr (REGEX_DEBUG) {
VERIFY(start_position + length <= input.view.length());
dbgln("Save named capture group with name={} and content='{}'", capture_group_name, input.view.substring_view(start_position, length));
}
VERIFY(start_position + length <= input.view.length());
VERIFY(start_position + length <= input.view.length());
auto view = input.view.substring_view(start_position, length);
if (input.regex_options & AllFlags::StringCopyMatches) {
map.set(capture_group_name, { view.to_string(), input.line, start_position, input.global_offset + start_position }); // create a copy of the original string
} else {
map.set(capture_group_name, { view, input.line, start_position, input.global_offset + start_position }); // take view to original string
}
auto view = input.view.substring_view(start_position, length);
if (input.regex_options & AllFlags::StringCopyMatches) {
match = { view.to_string(), name(), input.line, start_position, input.global_offset + start_position }; // create a copy of the original string
} else {
warnln("Didn't find corresponding capture group match for name={}, match_index={}", capture_group_name.to_string(), input.match_index);
match = { view, name(), input.line, start_position, input.global_offset + start_position }; // take view to original string
}
return ExecutionResult::Continue;
@ -543,24 +511,6 @@ ALWAYS_INLINE ExecutionResult OpCode_Compare::execute(MatchInput const& input, M
if (!compare_string(input, state, str, had_zero_length_match))
return ExecutionResult::Failed_ExecuteLowPrioForks;
} else if (compare_type == CharacterCompareType::NamedReference) {
auto ptr = (char const*)m_bytecode->at(offset++);
auto length = (size_t)m_bytecode->at(offset++);
StringView name { ptr, length };
auto group = state.named_capture_group_matches.at(input.match_index).get(name);
if (!group.has_value())
return ExecutionResult::Failed_ExecuteLowPrioForks;
auto str = group.value().view;
// We want to compare a string that is definitely longer than the available string
if (input.view.length() < state.string_position + str.length())
return ExecutionResult::Failed_ExecuteLowPrioForks;
if (!compare_string(input, state, str, had_zero_length_match))
return ExecutionResult::Failed_ExecuteLowPrioForks;
} else if (compare_type == CharacterCompareType::Property) {
auto property = static_cast<Unicode::Property>(m_bytecode->at(offset++));
compare_property(input, state, property, current_inversion_state(), inverse_matched);
@ -869,10 +819,6 @@ Vector<String> const OpCode_Compare::variable_arguments_to_string(Optional<Match
buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]));
}
}
} else if (compare_type == CharacterCompareType::NamedReference) {
auto ptr = (char const*)m_bytecode->at(offset++);
auto length = m_bytecode->at(offset++);
result.empend(String::formatted("name='{}'", StringView { ptr, (size_t)length }));
} else if (compare_type == CharacterCompareType::Reference) {
auto ref = m_bytecode->at(offset++);
result.empend(String::formatted("number={}", ref));