func StringMatcherFromProto()

in xds/utils/matcher/string_matcher.go [83:130]
47 lines of code
15 McCabe index (conditional complexity)

func StringMatcherFromProto(matcherProto *v3matcherpb.StringMatcher) (StringMatcher, error) {
	if matcherProto == nil {
		return StringMatcher{}, errors.New("input StringMatcher proto is nil")
	}

	matcher := StringMatcher{ignoreCase: matcherProto.GetIgnoreCase()}
	switch mt := matcherProto.GetMatchPattern().(type) {
	case *v3matcherpb.StringMatcher_Exact:
		matcher.exactMatch = &mt.Exact
		if matcher.ignoreCase {
			*matcher.exactMatch = strings.ToLower(*matcher.exactMatch)
		}
	case *v3matcherpb.StringMatcher_Prefix:
		if matcherProto.GetPrefix() == "" {
			return StringMatcher{}, errors.New("empty prefix is not allowed in StringMatcher")
		}
		matcher.prefixMatch = &mt.Prefix
		if matcher.ignoreCase {
			*matcher.prefixMatch = strings.ToLower(*matcher.prefixMatch)
		}
	case *v3matcherpb.StringMatcher_Suffix:
		if matcherProto.GetSuffix() == "" {
			return StringMatcher{}, errors.New("empty suffix is not allowed in StringMatcher")
		}
		matcher.suffixMatch = &mt.Suffix
		if matcher.ignoreCase {
			*matcher.suffixMatch = strings.ToLower(*matcher.suffixMatch)
		}
	case *v3matcherpb.StringMatcher_SafeRegex:
		regex := matcherProto.GetSafeRegex().GetRegex()
		re, err := regexp.Compile(regex)
		if err != nil {
			return StringMatcher{}, fmt.Errorf("safe_regex matcher %q is invalid", regex)
		}
		matcher.regexMatch = re
	case *v3matcherpb.StringMatcher_Contains:
		if matcherProto.GetContains() == "" {
			return StringMatcher{}, errors.New("empty contains is not allowed in StringMatcher")
		}
		matcher.containsMatch = &mt.Contains
		if matcher.ignoreCase {
			*matcher.containsMatch = strings.ToLower(*matcher.containsMatch)
		}
	default:
		return StringMatcher{}, fmt.Errorf("unrecognized string matcher: %+v", matcherProto)
	}
	return matcher, nil
}