78 lines
1.9 KiB
Go
78 lines
1.9 KiB
Go
// Copyright 2015 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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"fmt"
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"strings"
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"github.com/juju/errors"
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"github.com/pingcap/tidb/context"
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)
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// Row is the expression for row constructor.
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// See https://dev.mysql.com/doc/refman/5.7/en/row-subqueries.html
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type Row struct {
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Values []Expression
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}
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// Clone implements the Expression Clone interface.
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func (r *Row) Clone() Expression {
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values := make([]Expression, len(r.Values))
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for i, expr := range r.Values {
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values[i] = expr.Clone()
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}
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return &Row{Values: values}
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}
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// IsStatic implements the Expression IsStatic interface.
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func (r *Row) IsStatic() bool {
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for _, e := range r.Values {
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if !e.IsStatic() {
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return false
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}
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}
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return true
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}
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// String implements the Expression String interface.
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func (r *Row) String() string {
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ss := make([]string, len(r.Values))
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for i := range ss {
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ss[i] = r.Values[i].String()
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}
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return fmt.Sprintf("ROW(%s)", strings.Join(ss, ", "))
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}
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// Eval implements the Expression Eval interface.
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func (r *Row) Eval(ctx context.Context, args map[interface{}]interface{}) (interface{}, error) {
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row := make([]interface{}, len(r.Values))
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var err error
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for i, expr := range r.Values {
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row[i], err = expr.Eval(ctx, args)
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if err != nil {
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return nil, errors.Trace(err)
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}
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}
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return row, nil
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}
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// Accept implements Expression Accept interface.
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func (r *Row) Accept(v Visitor) (Expression, error) {
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return v.VisitRow(r)
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}
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