add previousgtidsevent (go-mysql-org#469)

* add previousgtidsevent

Co-authored-by: pomelo2016 <[email protected]>

Author: cenkore

replication/event.go

@@ -2,6 +2,7 @@ package replication
 
 import (
 	"encoding/binary"
+	"encoding/hex"
 	"fmt"
 	"io"
 	"strconv"
@@ -217,6 +218,55 @@ func (e *RotateEvent) Dump(w io.Writer) {
 	fmt.Fprintln(w)
 }
 
+type PreviousGTIDsEvent struct {
+	GTIDSets string
+}
+
+func (e *PreviousGTIDsEvent) Decode(data []byte) error {
+	var previousGTIDSets []string
+	pos := 0
+	uuidCount := binary.LittleEndian.Uint16(data[pos:pos+8])
+	pos += 8
+
+	for i := uint16(0);i < uuidCount; i++ {
+		uuid := e.decodeUuid(data[pos:pos+16])
+		pos += 16
+		sliceCount := binary.LittleEndian.Uint16(data[pos:pos+8])
+		pos += 8
+		var intervals []string
+		for i := uint16(0);i < sliceCount; i++ {
+			start := e.decodeInterval(data[pos:pos+8])
+			pos += 8
+			stop := e.decodeInterval(data[pos:pos+8])
+			pos += 8
+			interval := ""
+			if stop == start+1 {
+				interval = fmt.Sprintf("%d",start)
+			}else {
+				interval = fmt.Sprintf("%d-%d",start,stop-1)
+			}
+			intervals = append(intervals,interval)
+		}
+		previousGTIDSets = append(previousGTIDSets,fmt.Sprintf("%s:%s",uuid,strings.Join(intervals,":")))
+	}
+	e.GTIDSets = fmt.Sprintf("%s",strings.Join(previousGTIDSets,","))
+	return nil
+}
+
+func (e *PreviousGTIDsEvent) Dump(w io.Writer) {
+	fmt.Fprintf(w, "Previous GTID Event: %s\n", e.GTIDSets)
+	fmt.Fprintln(w)
+}
+
+func (e *PreviousGTIDsEvent) decodeUuid(data []byte) string {
+	return fmt.Sprintf("%s-%s-%s-%s-%s",hex.EncodeToString(data[0:4]),hex.EncodeToString(data[4:6]),
+		hex.EncodeToString(data[6:8]),hex.EncodeToString(data[8:10]),hex.EncodeToString(data[10:]))
+}
+
+func (e *PreviousGTIDsEvent) decodeInterval(data []byte) uint64 {
+	return binary.LittleEndian.Uint64(data)
+}
+
 type XIDEvent struct {
 	XID uint64
 

replication/parser.go

@@ -271,6 +271,8 @@ func (p *BinlogParser) parseEvent(h *EventHeader, data []byte, rawData []byte) (
 				ee := &MariadbGTIDEvent{}
 				ee.GTID.ServerID = h.ServerID
 				e = ee
+			case PREVIOUS_GTIDS_EVENT:
+				e = &PreviousGTIDsEvent{}
 			default:
 				e = &GenericEvent{}
 			}