forked from Shiloh/githaven
90 lines
2.1 KiB
Go
90 lines
2.1 KiB
Go
|
// Copyright 2015 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 plan
|
||
|
|
|
||
|
|
import (
|
||
|
|
"fmt"
|
||
|
|
"math"
|
||
|
|
"strings"
|
||
|
|
)
|
||
|
|
|
||
|
|
// ToString explains a Plan, returns description string.
|
||
|
|
func ToString(p Plan) string {
|
||
|
|
var e stringer
|
||
|
|
p.Accept(&e)
|
||
|
|
return strings.Join(e.strs, "->")
|
||
|
|
}
|
||
|
|
|
||
|
|
type stringer struct {
|
||
|
|
strs []string
|
||
|
|
idxs []int
|
||
|
|
}
|
||
|
|
|
||
|
|
func (e *stringer) Enter(in Plan) (Plan, bool) {
|
||
|
|
switch in.(type) {
|
||
|
|
case *JoinOuter, *JoinInner:
|
||
|
|
e.idxs = append(e.idxs, len(e.strs))
|
||
|
|
}
|
||
|
|
return in, false
|
||
|
|
}
|
||
|
|
|
||
|
|
func (e *stringer) Leave(in Plan) (Plan, bool) {
|
||
|
|
var str string
|
||
|
|
switch x := in.(type) {
|
||
|
|
case *CheckTable:
|
||
|
|
str = "CheckTable"
|
||
|
|
case *IndexScan:
|
||
|
|
str = fmt.Sprintf("Index(%s.%s)", x.Table.Name.L, x.Index.Name.L)
|
||
|
|
case *Limit:
|
||
|
|
str = "Limit"
|
||
|
|
case *SelectFields:
|
||
|
|
str = "Fields"
|
||
|
|
case *SelectLock:
|
||
|
|
str = "Lock"
|
||
|
|
case *ShowDDL:
|
||
|
|
str = "ShowDDL"
|
||
|
|
case *Sort:
|
||
|
|
str = "Sort"
|
||
|
|
case *TableScan:
|
||
|
|
if len(x.Ranges) > 0 {
|
||
|
|
ran := x.Ranges[0]
|
||
|
|
if ran.LowVal != math.MinInt64 || ran.HighVal != math.MaxInt64 {
|
||
|
|
str = fmt.Sprintf("Range(%s)", x.Table.Name.L)
|
||
|
|
} else {
|
||
|
|
str = fmt.Sprintf("Table(%s)", x.Table.Name.L)
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
str = fmt.Sprintf("Table(%s)", x.Table.Name.L)
|
||
|
|
}
|
||
|
|
case *JoinOuter:
|
||
|
|
last := len(e.idxs) - 1
|
||
|
|
idx := e.idxs[last]
|
||
|
|
chilrden := e.strs[idx:]
|
||
|
|
e.strs = e.strs[:idx]
|
||
|
|
str = "OuterJoin{" + strings.Join(chilrden, "->") + "}"
|
||
|
|
e.idxs = e.idxs[:last]
|
||
|
|
case *JoinInner:
|
||
|
|
last := len(e.idxs) - 1
|
||
|
|
idx := e.idxs[last]
|
||
|
|
chilrden := e.strs[idx:]
|
||
|
|
e.strs = e.strs[:idx]
|
||
|
|
str = "InnerJoin{" + strings.Join(chilrden, "->") + "}"
|
||
|
|
e.idxs = e.idxs[:last]
|
||
|
|
default:
|
||
|
|
str = fmt.Sprintf("%T", in)
|
||
|
|
}
|
||
|
|
e.strs = append(e.strs, str)
|
||
|
|
return in, true
|
||
|
|
}
|