83 lines
2.1 KiB
Go
83 lines
2.1 KiB
Go
// Copyright 2017 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package expression
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import (
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"bytes"
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"fmt"
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"github.com/pingcap/tidb/types"
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)
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// ExplainInfo implements the Expression interface.
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func (expr *ScalarFunction) ExplainInfo() string {
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buffer := bytes.NewBufferString(fmt.Sprintf("%s(", expr.FuncName.L))
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for i, arg := range expr.GetArgs() {
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buffer.WriteString(arg.ExplainInfo())
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if i+1 < len(expr.GetArgs()) {
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buffer.WriteString(", ")
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}
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}
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buffer.WriteString(")")
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return buffer.String()
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}
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// ExplainInfo implements the Expression interface.
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func (expr *Column) ExplainInfo() string {
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return expr.String()
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}
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// ExplainInfo implements the Expression interface.
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func (expr *Constant) ExplainInfo() string {
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dt, err := expr.Eval(nil)
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if err != nil {
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if expr.Value.Kind() == types.KindNull {
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return "null"
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}
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return "not recognized const vanue"
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}
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valStr, err := dt.ToString()
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if err != nil {
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if expr.Value.Kind() == types.KindNull {
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return "null"
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}
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return "not recognized const vanue"
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}
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return valStr
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}
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// ExplainExpressionList generates explain information for a list of expressions.
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func ExplainExpressionList(exprs []Expression) []byte {
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buffer := bytes.NewBufferString("")
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for i, expr := range exprs {
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buffer.WriteString(expr.ExplainInfo())
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if i+1 < len(exprs) {
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buffer.WriteString(", ")
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}
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}
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return buffer.Bytes()
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}
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// ExplainColumnList generates explain information for a list of columns.
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func ExplainColumnList(cols []*Column) []byte {
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buffer := bytes.NewBufferString("")
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for i, col := range cols {
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buffer.WriteString(col.ExplainInfo())
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if i+1 < len(cols) {
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buffer.WriteString(", ")
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}
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}
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return buffer.Bytes()
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}
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