ParseIntervalType()

Signed-off-by: Shlomi Noach <2607934+shlomi-noach@users.noreply.github.com>

go/mysql/datetime/interval.go

@@ -166,6 +166,54 @@ func (itv IntervalType) ToString() string {
 	}
 }
 
+// ParseIntervalType parses a string into an IntervalType. This is the inverse function of IntervalType.ToString().
+func ParseIntervalType(s string) IntervalType {
+	switch strings.ToLower(s) {
+	case "year":
+		return IntervalYear
+	case "quarter":
+		return IntervalQuarter
+	case "month":
+		return IntervalMonth
+	case "week":
+		return IntervalWeek
+	case "day":
+		return IntervalDay
+	case "hour":
+		return IntervalHour
+	case "minute":
+		return IntervalMinute
+	case "second":
+		return IntervalSecond
+	case "microsecond":
+		return IntervalMicrosecond
+	case "year_month":
+		return IntervalYearMonth
+	case "day_hour":
+		return IntervalDayHour
+	case "day_minute":
+		return IntervalDayMinute
+	case "day_second":
+		return IntervalDaySecond
+	case "hour_minute":
+		return IntervalHourMinute
+	case "hour_second":
+		return IntervalHourSecond
+	case "minute_second":
+		return IntervalMinuteSecond
+	case "day_microsecond":
+		return IntervalDayMicrosecond
+	case "hour_microsecond":
+		return IntervalHourMicrosecond
+	case "minute_microsecond":
+		return IntervalMinuteMicrosecond
+	case "second_microsecond":
+		return IntervalSecondMicrosecond
+	default:
+		return IntervalNone
+	}
+}
+
 func intervalSetYear(tp *Interval, val int) {
 	tp.year = val
 }

go/mysql/datetime/interval_test.go

@@ -17,9 +17,12 @@ limitations under the License.
 package datetime
 
 import (
+	"math"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	"vitess.io/vitess/go/mysql/decimal"
 )
@@ -367,3 +370,47 @@ func TestInRange(t *testing.T) {
 		assert.Equal(t, tc.wantInRange, got)
 	}
 }
+
+func TestParseIntervalType(t *testing.T) {
+	intervals := []IntervalType{
+		IntervalMicrosecond,
+		IntervalSecond,
+		IntervalMinute,
+		IntervalHour,
+		IntervalDay,
+		IntervalWeek,
+		IntervalMonth,
+		IntervalQuarter,
+		IntervalYear,
+		IntervalSecondMicrosecond,
+		IntervalMinuteMicrosecond,
+		IntervalMinuteSecond,
+		IntervalHourMicrosecond,
+		IntervalHourSecond,
+		IntervalHourMinute,
+		IntervalDayMicrosecond,
+		IntervalDaySecond,
+		IntervalDayMinute,
+		IntervalDayHour,
+		IntervalYearMonth,
+	}
+	for _, interval := range intervals {
+		s := interval.ToString()
+		t.Run(s, func(t *testing.T) {
+			require.NotEmpty(t, s)
+			require.NotEqual(t, "[unknown IntervalType]", s)
+			parsed := ParseIntervalType(s)
+			assert.NotEqual(t, IntervalNone, parsed)
+			assert.Equal(t, interval, parsed)
+
+			parsed = ParseIntervalType(strings.ToUpper(s))
+			assert.NotEqual(t, IntervalNone, parsed)
+			assert.Equal(t, interval, parsed)
+		})
+	}
+	interval := IntervalType(math.MaxUint8)
+	s := interval.ToString()
+	assert.Equal(t, "[unknown IntervalType]", s)
+	parsed := ParseIntervalType(s)
+	assert.Equal(t, IntervalNone, parsed)
+}