// Copyright 2018 PingCAP, Inc. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // See the License for the specific language governing permissions and // limitations under the License. package decoder import ( "sort" "time" "github.com/pingcap/parser/mysql" "github.com/pingcap/tidb/expression" "github.com/pingcap/tidb/sessionctx" "github.com/pingcap/tidb/table" "github.com/pingcap/tidb/table/tables" "github.com/pingcap/tidb/tablecodec" "github.com/pingcap/tidb/types" "github.com/pingcap/tidb/util/chunk" "github.com/pingcap/tidb/util/rowcodec" ) // Column contains the info and generated expr of column. type Column struct { Col *table.Column GenExpr expression.Expression } // RowDecoder decodes a byte slice into datums and eval the generated column value. type RowDecoder struct { tbl table.Table mutRow chunk.MutRow columns map[int64]Column colTypes map[int64]*types.FieldType defaultVals []types.Datum } // NewRowDecoder returns a new RowDecoder. func NewRowDecoder(tbl table.Table, decodeColMap map[int64]Column) *RowDecoder { colFieldMap := make(map[int64]*types.FieldType, len(decodeColMap)) for id, col := range decodeColMap { colFieldMap[id] = &col.Col.ColumnInfo.FieldType } cols := tbl.Cols() tps := make([]*types.FieldType, len(cols)) for _, col := range cols { tps[col.Offset] = &col.FieldType } return &RowDecoder{ tbl: tbl, mutRow: chunk.MutRowFromTypes(tps), columns: decodeColMap, colTypes: colFieldMap, defaultVals: make([]types.Datum, len(cols)), } } // DecodeAndEvalRowWithMap decodes a byte slice into datums and evaluates the generated column value. func (rd *RowDecoder) DecodeAndEvalRowWithMap(ctx sessionctx.Context, handle int64, b []byte, decodeLoc, sysLoc *time.Location, row map[int64]types.Datum) (map[int64]types.Datum, error) { var err error if rowcodec.IsNewFormat(b) { row, err = tablecodec.DecodeRowWithMapNew(b, rd.colTypes, decodeLoc, row) } else { row, err = tablecodec.DecodeRowWithMap(b, rd.colTypes, decodeLoc, row) } if err != nil { return nil, err } for _, dCol := range rd.columns { colInfo := dCol.Col.ColumnInfo val, ok := row[colInfo.ID] if ok || dCol.GenExpr != nil { rd.mutRow.SetValue(colInfo.Offset, val.GetValue()) continue } // Get the default value of the column in the generated column expression. if dCol.Col.IsPKHandleColumn(rd.tbl.Meta()) { if mysql.HasUnsignedFlag(colInfo.Flag) { val.SetUint64(uint64(handle)) } else { val.SetInt64(handle) } } else { val, err = tables.GetColDefaultValue(ctx, dCol.Col, rd.defaultVals) if err != nil { return nil, err } } rd.mutRow.SetValue(colInfo.Offset, val.GetValue()) } keys := make([]int, 0) ids := make(map[int]int) for k, col := range rd.columns { keys = append(keys, col.Col.Offset) ids[col.Col.Offset] = int(k) } sort.Ints(keys) for _, id := range keys { col := rd.columns[int64(ids[id])] if col.GenExpr == nil { continue } // Eval the column value val, err := col.GenExpr.Eval(rd.mutRow.ToRow()) if err != nil { return nil, err } val, err = table.CastValue(ctx, val, col.Col.ColumnInfo, false, true) if err != nil { return nil, err } if val.Kind() == types.KindMysqlTime && sysLoc != time.UTC { t := val.GetMysqlTime() if t.Type() == mysql.TypeTimestamp { err := t.ConvertTimeZone(sysLoc, time.UTC) if err != nil { return nil, err } val.SetMysqlTime(t) } } rd.mutRow.SetValue(col.Col.Offset, val.GetValue()) row[int64(ids[id])] = val } return row, nil } // BuildFullDecodeColMap build a map that contains [columnID -> struct{*table.Column, expression.Expression}] from all columns. func BuildFullDecodeColMap(t table.Table, schema *expression.Schema) map[int64]Column { decodeColMap := make(map[int64]Column, len(t.Cols())) for _, col := range t.Cols() { decodeColMap[col.ID] = Column{ Col: col, GenExpr: schema.Columns[col.Offset].VirtualExpr, } } return decodeColMap }