Skip to content
Permalink
Branch: master
Find file Copy path
Find file Copy path
Fetching contributors…
Cannot retrieve contributors at this time
156 lines (139 sloc) 4.51 KB
// Copyright 2017 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 expression
import (
"bytes"
"fmt"
"sort"
"strings"
"github.com/pingcap/tidb/types"
"github.com/pingcap/tidb/util/chunk"
)
// ExplainInfo implements the Expression interface.
func (expr *ScalarFunction) ExplainInfo() string {
return expr.explainInfo(false)
}
func (expr *ScalarFunction) explainInfo(normalized bool) string {
var buffer bytes.Buffer
fmt.Fprintf(&buffer, "%s(", expr.FuncName.L)
for i, arg := range expr.GetArgs() {
if normalized {
buffer.WriteString(arg.ExplainNormalizedInfo())
} else {
buffer.WriteString(arg.ExplainInfo())
}
if i+1 < len(expr.GetArgs()) {
buffer.WriteString(", ")
}
}
buffer.WriteString(")")
return buffer.String()
}
// ExplainNormalizedInfo implements the Expression interface.
func (expr *ScalarFunction) ExplainNormalizedInfo() string {
return expr.explainInfo(true)
}
// ExplainInfo implements the Expression interface.
func (col *Column) ExplainInfo() string {
return col.String()
}
// ExplainNormalizedInfo implements the Expression interface.
func (col *Column) ExplainNormalizedInfo() string {
return col.ExplainInfo()
}
// ExplainInfo implements the Expression interface.
func (expr *Constant) ExplainInfo() string {
dt, err := expr.Eval(chunk.Row{})
if err != nil {
return "not recognized const vanue"
}
return expr.format(dt)
}
// ExplainNormalizedInfo implements the Expression interface.
func (expr *Constant) ExplainNormalizedInfo() string {
return "?"
}
func (expr *Constant) format(dt types.Datum) string {
switch dt.Kind() {
case types.KindNull:
return "NULL"
case types.KindString, types.KindBytes, types.KindMysqlEnum, types.KindMysqlSet,
types.KindMysqlJSON, types.KindBinaryLiteral, types.KindMysqlBit:
return fmt.Sprintf("\"%v\"", dt.GetValue())
}
return fmt.Sprintf("%v", dt.GetValue())
}
// ExplainExpressionList generates explain information for a list of expressions.
func ExplainExpressionList(exprs []Expression, schema *Schema) string {
builder := &strings.Builder{}
for i, expr := range exprs {
switch expr.(type) {
case *Column, *CorrelatedColumn:
builder.WriteString(expr.String())
default:
fmt.Fprintf(builder, "%v->%v", expr.String(), schema.Columns[i])
}
if i+1 < len(exprs) {
builder.WriteString(", ")
}
}
return builder.String()
}
// SortedExplainExpressionList generates explain information for a list of expressions in order.
// In some scenarios, the expr's order may not be stable when executing multiple times.
// So we add a sort to make its explain result stable.
func SortedExplainExpressionList(exprs []Expression) []byte {
return sortedExplainExpressionList(exprs, false)
}
func sortedExplainExpressionList(exprs []Expression, normalized bool) []byte {
buffer := bytes.NewBufferString("")
exprInfos := make([]string, 0, len(exprs))
for _, expr := range exprs {
if normalized {
exprInfos = append(exprInfos, expr.ExplainNormalizedInfo())
} else {
exprInfos = append(exprInfos, expr.ExplainInfo())
}
}
sort.Strings(exprInfos)
for i, info := range exprInfos {
buffer.WriteString(info)
if i+1 < len(exprInfos) {
buffer.WriteString(", ")
}
}
return buffer.Bytes()
}
// SortedExplainNormalizedExpressionList is same like SortedExplainExpressionList, but use for generating normalized information.
func SortedExplainNormalizedExpressionList(exprs []Expression) []byte {
return sortedExplainExpressionList(exprs, true)
}
// SortedExplainNormalizedScalarFuncList is same like SortedExplainExpressionList, but use for generating normalized information.
func SortedExplainNormalizedScalarFuncList(exprs []*ScalarFunction) []byte {
expressions := make([]Expression, len(exprs))
for i := range exprs {
expressions[i] = exprs[i]
}
return sortedExplainExpressionList(expressions, true)
}
// ExplainColumnList generates explain information for a list of columns.
func ExplainColumnList(cols []*Column) []byte {
buffer := bytes.NewBufferString("")
for i, col := range cols {
buffer.WriteString(col.ExplainInfo())
if i+1 < len(cols) {
buffer.WriteString(", ")
}
}
return buffer.Bytes()
}
You can’t perform that action at this time.