Add some helper methods to TableMapEvent

Author: huangjunwen

mysql/type.go

@@ -0,0 +1,21 @@
+package mysql
+
+// IsNumericType returns true if the given type is numeric.
+func IsNumericType(typ byte) bool {
+switch typ {
+case MYSQL_TYPE_TINY,
+MYSQL_TYPE_SHORT,
+MYSQL_TYPE_INT24,
+MYSQL_TYPE_LONG,
+MYSQL_TYPE_LONGLONG,
+MYSQL_TYPE_FLOAT,
+MYSQL_TYPE_DOUBLE,
+MYSQL_TYPE_DECIMAL,
+MYSQL_TYPE_NEWDECIMAL:
+return true
+
+default:
+return false
+}
+
+}

replication/row_event.go

@@ -37,9 +37,9 @@ type TableMapEvent struct {
 // The followings are available only after MySQL-8.0.1, see: `--binlog_row_metadata` and
 // https://mysqlhighavailability.com/more-metadata-is-written-into-binary-log/
 
-OptionalMeta []byte
+optionalMeta []byte
 
-SignednessBitmap []byte // len = (ColumnCount + 7) / 8
+SignednessBitmap []byte
 ColumnName [][]byte
 PrimaryKey []uint64 // A sequence of column indexes
 PrimaryKeyPrefix []uint64 // Prefix length 0 means that the whole column value is used
@@ -99,12 +99,12 @@ func (e *TableMapEvent) Decode(data []byte) error {
 
 pos += nullBitmapSize
 
-e.OptionalMeta = data[pos:]
-if len(e.OptionalMeta) == 0 {
+e.optionalMeta = data[pos:]
+if len(e.optionalMeta) == 0 {
 return nil
 }
 
-if err = e.decodeOptionalMeta(e.OptionalMeta); err != nil {
+if err = e.decodeOptionalMeta(e.optionalMeta); err != nil {
 return err
 }
 
@@ -259,6 +259,7 @@ func (e *TableMapEvent) decodeOptionalMeta(data []byte) error {
 }
 
 default:
+// TODO: other meta
 }
 
 }
@@ -275,17 +276,86 @@ func (e *TableMapEvent) Dump(w io.Writer) {
 fmt.Fprintf(w, "Column count: %d\n", e.ColumnCount)
 fmt.Fprintf(w, "Column type: \n%s", hex.Dump(e.ColumnType))
 fmt.Fprintf(w, "NULL bitmap: \n%s", hex.Dump(e.NullBitmap))
-fmt.Fprintf(w, "Optional meta: \n%s", hex.Dump(e.OptionalMeta))
-fmt.Fprintf(w, "Signedness bitmap\n%s", hex.Dump(e.SignednessBitmap))
-fmt.Fprintf(w, "Column name: \n")
-for _, name := range e.ColumnName {
-fmt.Fprintf(w, " %s\n", name)
-}
+fmt.Fprintf(w, "Optional meta: \n%s", hex.Dump(e.optionalMeta))
+fmt.Fprintf(w, "Signedness bitmap: \n%s", hex.Dump(e.SignednessBitmap))
 fmt.Fprintf(w, "Primary key: %v\n", e.PrimaryKey)
 fmt.Fprintf(w, "Primary key prefix: %v\n", e.PrimaryKeyPrefix)
+
+colNameArr := e.ColumnNameArray()
+nullArr := e.NullableArray()
+unsignedArr := e.UnsignedArray()
+fmt.Fprintf(w, "Columns: \n")
+for i := 0; i < int(e.ColumnCount); i++ {
+if colNameArr != nil {
+fmt.Fprintf(w, " %s", colNameArr[i])
+} else {
+fmt.Fprintf(w, " <noname>")
+}
+
+fmt.Fprintf(w, " type:%d", e.ColumnType[i])
+
+if unsignedArr != nil && unsignedArr[i] {
+fmt.Fprintf(w, " unsigned")
+}
+
+if nullArr != nil {
+if nullArr[i] {
+fmt.Fprintf(w, " null")
+} else {
+fmt.Fprintf(w, " notnull")
+}
+}
+
+fmt.Fprintf(w, "\n")
+}
 fmt.Fprintln(w)
 }
 
+// NullableArray returns an array of nullablity for each column: true if the column is nullable.
+// It returns nil if not available.
+func (e *TableMapEvent) NullableArray() []bool {
+if len(e.NullBitmap) == 0 {
+return nil
+}
+ret := make([]bool, e.ColumnCount)
+for i := 0; i < len(ret); i++ {
+ret[i] = e.NullBitmap[i/8]&(1<<(i%8)) != 0
+}
+return ret
+}
+
+// ColumnNameArray returns an array of column names.
+// It returns nil if not available.
+func (e *TableMapEvent) ColumnNameArray() []string {
+if len(e.ColumnName) == 0 {
+return nil
+}
+ret := make([]string, e.ColumnCount)
+for i := 0; i < len(ret); i++ {
+ret[i] = string(e.ColumnName[i])
+}
+return ret
+}
+
+// UnsignedArray returns an array of signedness for each column: true if the column is numeric and it's unsigned.
+// It returns nil if not available.
+func (e *TableMapEvent) UnsignedArray() []bool {
+if len(e.SignednessBitmap) == 0 {
+return nil
+}
+p := 0
+ret := make([]bool, e.ColumnCount)
+for i := 0; i < len(ret); i++ {
+if !IsNumericType(e.ColumnType[i]) {
+ret[i] = false
+continue
+}
+ret[i] = e.SignednessBitmap[p/8]&(1<<(7-p%8)) != 0
+p++
+}
+return ret
+}
+
 // RowsEventStmtEndFlag is set in the end of the statement.
 const RowsEventStmtEndFlag = 0x01