matches method

bool matches(PublicationTopic matcheeTopic)

Checks if the rawTopic matches the supplied rawTopic using the MQTT rawTopic matching rules. Returns true if the rawTopic matches based on the MQTT rawTopic matching rules, otherwise false.

Implementation

bool matches(PublicationTopic matcheeTopic) {
  // If the left rawTopic is just a multi wildcard then we
  // have a match without
  // needing to check any further.
  if (rawTopic == Topic.multiWildcard) {
    return true;
  }
  // If the topics are an exact match, bail early with a cheap comparison
  if (rawTopic == matcheeTopic.rawTopic) {
    return true;
  }
  // no match yet so we need to check each fragment
  for (var i = 0; i < topicFragments.length; i++) {
    final lhsFragment = topicFragments[i];
    // If we've reached a multi wildcard in the lhs rawTopic,
    // we have a match.
    // (this is the mqtt spec rule finance matches finance or finance/#)
    if (lhsFragment == Topic.multiWildcard) {
      return true;
    }
    final isLhsWildcard = lhsFragment == Topic.wildcard;
    // If we've reached a wildcard match but the matchee does
    // not have anything at this fragment level then it's not a match.
    // (this is the MQTT spec rule 'finance does not match finance/+'
    if (isLhsWildcard && matcheeTopic.topicFragments.length <= i) {
      return false;
    }
    // if lhs is not a wildcard we need to check whether the
    // two fragments match each other.
    if (!isLhsWildcard) {
      final rhsFragment = matcheeTopic.topicFragments[i];
      // If the hs fragment is not wildcard then we need an exact match
      if (lhsFragment != rhsFragment) {
        return false;
      }
    }
    // If we're at the last fragment of the lhs rawTopic but there are
    // more fragments in the in the matchee then the matchee rawTopic
    // is too specific to be a match.
    if (i + 1 == topicFragments.length &&
        matcheeTopic.topicFragments.length > topicFragments.length) {
      return false;
    }
    // If we're here the current fragment matches so check the next
  }
  // If we exit out of the loop without a return then we have a full match rawTopic/rawTopic which would
  // have been caught by the original exact match check at the top anyway.
  return true;
}