86 lines
2.2 KiB
Go
86 lines
2.2 KiB
Go
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package binlog
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import (
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"github.com/localhots/blt/mysql"
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"github.com/localhots/blt/tools"
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)
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// TableDescription contains table details required to process rows events.
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type TableDescription struct {
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Flags uint16
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SchemaName string
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TableName string
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ColumnCount uint64
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ColumnTypes []byte
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ColumnMeta []uint16
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NullBitmask []byte
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}
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// TableMapEvent contains table description alongside an ID that would be used
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// to reference the table in the following rows events.
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type TableMapEvent struct {
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TableID uint64
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TableDescription
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}
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// Decode decodes given buffer into a table map event.
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// Spec: https://dev.mysql.com/doc/internals/en/table-map-event.html
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func (e *TableMapEvent) Decode(connBuff []byte, fd FormatDescription) error {
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buf := tools.NewBuffer(connBuff)
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idSize := fd.TableIDSize(EventTypeTableMap)
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if idSize == 6 {
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e.TableID = buf.ReadUint48()
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} else {
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e.TableID = uint64(buf.ReadUint32())
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}
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e.Flags = buf.ReadUint16()
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schemaName, _ := buf.ReadStringLenEnc()
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e.SchemaName = string(schemaName)
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buf.Skip(1) // Always 0x00
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tableName, _ := buf.ReadStringLenEnc()
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e.TableName = string(tableName)
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buf.Skip(1) // Always 0x00
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e.ColumnCount, _, _ = buf.ReadUintLenEnc()
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e.ColumnTypes = buf.ReadStringVarLen(int(e.ColumnCount))
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colMeta, _ := buf.ReadStringLenEnc()
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e.ColumnMeta = decodeColumnMeta(colMeta, e.ColumnTypes)
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e.NullBitmask = buf.ReadStringVarLen(int(e.ColumnCount+8) / 7)
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return nil
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}
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func decodeColumnMeta(data []byte, cols []byte) []uint16 {
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pos := 0
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meta := make([]uint16, len(cols))
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for i, typ := range cols {
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switch mysql.ColumnType(typ) {
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case mysql.ColumnTypeString,
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mysql.ColumnTypeNewDecimal:
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// TODO: Is that correct?
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meta[i] = uint16(data[pos])<<8 | uint16(data[pos+1])
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pos += 2
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case mysql.ColumnTypeVarchar,
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mysql.ColumnTypeVarstring,
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mysql.ColumnTypeBit:
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// TODO: Is that correct?
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meta[i] = mysql.DecodeUint16(data[pos:])
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pos += 2
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case mysql.ColumnTypeFloat,
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mysql.ColumnTypeDouble,
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mysql.ColumnTypeBlob,
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mysql.ColumnTypeGeometry,
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mysql.ColumnTypeJSON,
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mysql.ColumnTypeTime2,
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mysql.ColumnTypeDatetime2,
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mysql.ColumnTypeTimestamp2:
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meta[i] = uint16(data[pos])
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pos++
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}
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}
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return meta
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}
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