virtual bool MatchAndExplain()

in ext/gtest-1.8.0/googlemock/include/gmock/gmock-matchers.h [3161:3239]

• 54 lines of code
• 15 McCabe index (conditional complexity)

  virtual bool MatchAndExplain(Container container,
                               MatchResultListener* listener) const {
    // To work with stream-like "containers", we must only walk
    // through the elements in one pass.

    const bool listener_interested = listener->IsInterested();

    // explanations[i] is the explanation of the element at index i.
    ::std::vector<internal::string> explanations(count());
    StlContainerReference stl_container = View::ConstReference(container);
    typename StlContainer::const_iterator it = stl_container.begin();
    size_t exam_pos = 0;
    bool mismatch_found = false;  // Have we found a mismatched element yet?

    // Go through the elements and matchers in pairs, until we reach
    // the end of either the elements or the matchers, or until we find a
    // mismatch.
    for (; it != stl_container.end() && exam_pos != count(); ++it, ++exam_pos) {
      bool match;  // Does the current element match the current matcher?
      if (listener_interested) {
        StringMatchResultListener s;
        match = matchers_[exam_pos].MatchAndExplain(*it, &s);
        explanations[exam_pos] = s.str();
      } else {
        match = matchers_[exam_pos].Matches(*it);
      }

      if (!match) {
        mismatch_found = true;
        break;
      }
    }
    // If mismatch_found is true, 'exam_pos' is the index of the mismatch.

    // Find how many elements the actual container has.  We avoid
    // calling size() s.t. this code works for stream-like "containers"
    // that don't define size().
    size_t actual_count = exam_pos;
    for (; it != stl_container.end(); ++it) {
      ++actual_count;
    }

    if (actual_count != count()) {
      // The element count doesn't match.  If the container is empty,
      // there's no need to explain anything as Google Mock already
      // prints the empty container.  Otherwise we just need to show
      // how many elements there actually are.
      if (listener_interested && (actual_count != 0)) {
        *listener << "which has " << Elements(actual_count);
      }
      return false;
    }

    if (mismatch_found) {
      // The element count matches, but the exam_pos-th element doesn't match.
      if (listener_interested) {
        *listener << "whose element #" << exam_pos << " doesn't match";
        PrintIfNotEmpty(explanations[exam_pos], listener->stream());
      }
      return false;
    }

    // Every element matches its expectation.  We need to explain why
    // (the obvious ones can be skipped).
    if (listener_interested) {
      bool reason_printed = false;
      for (size_t i = 0; i != count(); ++i) {
        const internal::string& s = explanations[i];
        if (!s.empty()) {
          if (reason_printed) {
            *listener << ",\nand ";
          }
          *listener << "whose element #" << i << " matches, " << s;
          reason_printed = true;
        }
      }
    }
    return true;
  }