feat: support array in default and options tags (#1386)

* feat: support array in default and options tags

* feat: ignore spaces in tags

* test: add more tests

core/mapping/utils.go

@@ -14,13 +14,19 @@ import (
 )
 
 const (
-	defaultOption   = "default"
-	stringOption    = "string"
-	optionalOption  = "optional"
-	optionsOption   = "options"
-	rangeOption     = "range"
-	optionSeparator = "|"
-	equalToken      = "="
+	defaultOption      = "default"
+	stringOption       = "string"
+	optionalOption     = "optional"
+	optionsOption      = "options"
+	rangeOption        = "range"
+	optionSeparator    = "|"
+	equalToken         = "="
+	escapeChar         = '\\'
+	leftBracket        = '('
+	rightBracket       = ')'
+	leftSquareBracket  = '['
+	rightSquareBracket = ']'
+	segmentSeparator   = ','
 )
 
 var (
@@ -118,7 +124,7 @@ func convertType(kind reflect.Kind, str string) (interface{}, error) {
 }
 
 func doParseKeyAndOptions(field reflect.StructField, value string) (string, *fieldOptions, error) {
-	segments := strings.Split(value, ",")
+	segments := parseSegments(value)
 	key := strings.TrimSpace(segments[0])
 	options := segments[1:]
 
@@ -198,6 +204,16 @@ func maybeNewValue(field reflect.StructField, value reflect.Value) {
 	}
 }
 
+func parseGroupedSegments(val string) []string {
+	val = strings.TrimLeftFunc(val, func(r rune) bool {
+		return r == leftBracket || r == leftSquareBracket
+	})
+	val = strings.TrimRightFunc(val, func(r rune) bool {
+		return r == rightBracket || r == rightSquareBracket
+	})
+	return parseSegments(val)
+}
+
 // don't modify returned fieldOptions, it's cached and shared among different calls.
 func parseKeyAndOptions(tagName string, field reflect.StructField) (string, *fieldOptions, error) {
 	value := field.Tag.Get(tagName)
@@ -309,7 +325,7 @@ func parseOption(fieldOpts *fieldOptions, fieldName, option string) error {
 			return fmt.Errorf("field %s has wrong options", fieldName)
 		}
 
-		fieldOpts.Options = strings.Split(segs[1], optionSeparator)
+		fieldOpts.Options = parseOptions(segs[1])
 	case strings.HasPrefix(option, defaultOption):
 		segs := strings.Split(option, equalToken)
 		if len(segs) != 2 {
@@ -334,6 +350,69 @@ func parseOption(fieldOpts *fieldOptions, fieldName, option string) error {
 	return nil
 }
 
+// parseOptions parses the given options in tag.
+// for example: `json:"name,options=foo|bar"` or `json:"name,options=[foo,bar]"`
+func parseOptions(val string) []string {
+	if len(val) == 0 {
+		return nil
+	}
+
+	if val[0] == leftSquareBracket {
+		return parseGroupedSegments(val)
+	}
+
+	return strings.Split(val, optionSeparator)
+}
+
+func parseSegments(val string) []string {
+	var segments []string
+	var escaped, grouped bool
+	var buf strings.Builder
+
+	for _, ch := range val {
+		if escaped {
+			buf.WriteRune(ch)
+			escaped = false
+			continue
+		}
+
+		switch ch {
+		case segmentSeparator:
+			if grouped {
+				buf.WriteRune(ch)
+			} else {
+				// need to trim spaces, but we cannot ignore empty string,
+				// because the first segment stands for the key might be empty.
+				// if ignored, the later tag will be used as the key.
+				segments = append(segments, strings.TrimSpace(buf.String()))
+				buf.Reset()
+			}
+		case escapeChar:
+			if grouped {
+				buf.WriteRune(ch)
+			} else {
+				escaped = true
+			}
+		case leftBracket, leftSquareBracket:
+			buf.WriteRune(ch)
+			grouped = true
+		case rightBracket, rightSquareBracket:
+			buf.WriteRune(ch)
+			grouped = false
+		default:
+			buf.WriteRune(ch)
+		}
+	}
+
+	last := strings.TrimSpace(buf.String())
+	// ignore last empty string
+	if len(last) > 0 {
+		segments = append(segments, last)
+	}
+
+	return segments
+}
+
 func reprOfValue(val reflect.Value) string {
 	switch vt := val.Interface().(type) {
 	case bool: