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LibRegex: Correctly handle failing in the middle of explicit repeats

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- Make sure that all the Repeat ops are reset (otherwise the operation
  would not be correct when going over the Repeat op a second time)
- Make sure that all matches that are allowed to fail are backed by a
  fork, otherwise the last failing fork would not have anywhere to
  return to.
Fixes #9707.
This commit is contained in:
Ali Mohammad Pur 2021-08-31 22:27:08 +04:30 • committed by Andreas Kling
parent fcdd7aa990
commit dd82c2e9b4
3 changed files with 59 additions and 24 deletions
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56
Userland/Libraries/LibRegex/RegexByteCode.h
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@ -41,6 +41,7 @@ using ByteCodeValueType = u64;
__ENUMERATE_OPCODE(GoBack) \
__ENUMERATE_OPCODE(ClearCaptureGroup) \
__ENUMERATE_OPCODE(Repeat) \
__ENUMERATE_OPCODE(ResetRepeat) \
__ENUMERATE_OPCODE(Exit)
// clang-format off
@ -333,40 +334,46 @@ public:
}
template<typename T>
static void transform_bytecode_repetition_min_max(ByteCode& bytecode_to_repeat, T minimum, Optional<T> maximum, size_t repetition_mark_id, bool greedy = true) requires(IsIntegral<T>)
static void transform_bytecode_repetition_min_max(ByteCode& bytecode_to_repeat, T minimum, Optional<T> maximum, size_t min_repetition_mark_id, size_t max_repetition_mark_id, bool greedy = true) requires(IsIntegral<T>)
{
ByteCode new_bytecode;
new_bytecode.insert_bytecode_repetition_n(bytecode_to_repeat, minimum, repetition_mark_id);
new_bytecode.insert_bytecode_repetition_n(bytecode_to_repeat, minimum, min_repetition_mark_id);
if (maximum.has_value()) {
// (REPEAT REGEXP MIN)
// LABEL _MAX_LOOP |
// FORK END |
// REGEXP |
// REPEAT _MAX_LOOP MAX-1 | if max > min
// REGEXP |
// FORK END |
// LABEL END |
// LABEL _MAX_LOOP |
// FORK END |
// REGEXP |
// REPEAT _MAX_LOOP MAX-MIN | if max > min
// FORK END |
// REGEXP |
// LABEL END |
// RESET _MAX_LOOP |
auto jump_kind = static_cast<ByteCodeValueType>(greedy ? OpCodeId::ForkStay : OpCodeId::ForkJump);
if (maximum.value() > minimum) {
new_bytecode.empend(jump_kind);
new_bytecode.empend((ByteCodeValueType)0); // Placeholder for the jump target.
auto pre_loop_fork_jump_index = new_bytecode.size();
new_bytecode.extend(bytecode_to_repeat);
auto repetitions = maximum.value() - minimum;
dbgln("max {}, min {}, reps {}", *maximum, minimum, repetitions);
auto fork_jump_address = new_bytecode.size();
if (repetitions > 1) {
new_bytecode.extend(bytecode_to_repeat);
new_bytecode.empend((ByteCodeValueType)OpCodeId::Repeat);
new_bytecode.empend(bytecode_to_repeat.size() + 2);
new_bytecode.empend(static_cast<ByteCodeValueType>(repetitions - 1));
new_bytecode.empend(repetition_mark_id);
new_bytecode.empend(max_repetition_mark_id);
new_bytecode.empend(jump_kind);
new_bytecode.empend((ByteCodeValueType)0); // Placeholder for the jump target.
auto post_loop_fork_jump_index = new_bytecode.size();
new_bytecode.extend(bytecode_to_repeat);
fork_jump_address = new_bytecode.size();
new_bytecode[post_loop_fork_jump_index - 1] = (ByteCodeValueType)(fork_jump_address - post_loop_fork_jump_index);
new_bytecode.empend((ByteCodeValueType)OpCodeId::ResetRepeat);
new_bytecode.empend((ByteCodeValueType)max_repetition_mark_id);
}
new_bytecode.extend(bytecode_to_repeat);
new_bytecode.empend(jump_kind);
new_bytecode.empend((ByteCodeValueType)0); // Placeholder for the jump target.
auto post_loop_fork_jump_index = new_bytecode.size();
new_bytecode[pre_loop_fork_jump_index - 1] = (ByteCodeValueType)(new_bytecode.size() - pre_loop_fork_jump_index);
new_bytecode[post_loop_fork_jump_index - 1] = (ByteCodeValueType)(new_bytecode.size() - post_loop_fork_jump_index);
new_bytecode[pre_loop_fork_jump_index - 1] = (ByteCodeValueType)(fork_jump_address - pre_loop_fork_jump_index);
}
} else {
// no maximum value set, repeat finding if possible
@ -724,6 +731,19 @@ public:
}
};
class OpCode_ResetRepeat : public OpCode {
public:
ExecutionResult execute(MatchInput const& input, MatchState& state) const override;
ALWAYS_INLINE OpCodeId opcode_id() const override { return OpCodeId::ResetRepeat; }
ALWAYS_INLINE size_t size() const override { return 2; }
ALWAYS_INLINE size_t id() const { return argument(0); }
String const arguments_string() const override
{
auto reps = id() < state().repetition_marks.size() ? state().repetition_marks.at(id()) : 0;
return String::formatted("id={} rep={}", id(), reps + 1);
}
};
template<typename T>
bool is(OpCode const&);