func RouteToMatcher()

in xds/client/resource/matcher.go [43:84]
40 lines of code
16 McCabe index (conditional complexity)

func RouteToMatcher(r *Route) (*CompositeMatcher, error) {
	var pm pathMatcher
	switch {
	case r.Regex != nil:
		pm = newPathRegexMatcher(r.Regex)
	case r.Path != nil:
		pm = newPathExactMatcher(*r.Path, r.CaseInsensitive)
	case r.Prefix != nil:
		pm = newPathPrefixMatcher(*r.Prefix, r.CaseInsensitive)
	default:
		return nil, fmt.Errorf("illegal route: missing path_matcher")
	}

	headerMatchers := make([]matcher.HeaderMatcher, 0, len(r.Headers))
	for _, h := range r.Headers {
		var matcherT matcher.HeaderMatcher
		invert := h.InvertMatch != nil && *h.InvertMatch
		switch {
		case h.ExactMatch != nil && *h.ExactMatch != "":
			matcherT = matcher.NewHeaderExactMatcher(h.Name, *h.ExactMatch, invert)
		case h.RegexMatch != nil:
			matcherT = matcher.NewHeaderRegexMatcher(h.Name, h.RegexMatch, invert)
		case h.PrefixMatch != nil && *h.PrefixMatch != "":
			matcherT = matcher.NewHeaderPrefixMatcher(h.Name, *h.PrefixMatch, invert)
		case h.SuffixMatch != nil && *h.SuffixMatch != "":
			matcherT = matcher.NewHeaderSuffixMatcher(h.Name, *h.SuffixMatch, invert)
		case h.RangeMatch != nil:
			matcherT = matcher.NewHeaderRangeMatcher(h.Name, h.RangeMatch.Start, h.RangeMatch.End, invert)
		case h.PresentMatch != nil:
			matcherT = matcher.NewHeaderPresentMatcher(h.Name, *h.PresentMatch, invert)
		default:
			return nil, fmt.Errorf("illegal route: missing header_match_specifier")
		}
		headerMatchers = append(headerMatchers, matcherT)
	}

	var fractionMatcher *fractionMatcher
	if r.Fraction != nil {
		fractionMatcher = newFractionMatcher(*r.Fraction)
	}
	return newCompositeMatcher(pm, headerMatchers, fractionMatcher), nil
}