Function ChildArgsChanged

extern/re2/re2/simplify.cc:204–216

Utility function for PostVisit implementations that compares re->sub() with child_args to determine whether any child_args changed. In the common case, where nothing changed, calls Decref() for all child_args and returns false, so PostVisit must return re->Incref(). Otherwise, returns true.

// where nothing changed, calls Decref() for all child_args and returns false,
// so PostVisit must return re->Incref(). Otherwise, returns true.
static bool ChildArgsChanged(Regexp* re, Regexp** child_args) {
  for (int i = 0; i < re->nsub(); i++) {
    Regexp* sub = re->sub()[i];
    Regexp* newsub = child_args[i];
    if (newsub != sub)
      return true;
  }
  for (int i = 0; i < re->nsub(); i++) {
    Regexp* newsub = child_args[i];
    newsub->Decref();
  }
  return false;
}

Regexp* CoalesceWalker::Copy(Regexp* re) {
  return re->Incref();