add previousgtidsevent (go-mysql-org#469)

* add previousgtidsevent Co-authored-by: pomelo2016 <thsun@ctrip.com>

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{}
 }