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explain.go
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explain.go
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// Copyright 2016 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 executor
import (
"github.com/pingcap/tidb/expression"
)
// ExplainExec represents an explain executor.
type ExplainExec struct {
baseExecutor
rows []Row
cursor int
}
// Schema implements the Executor Schema interface.
func (e *ExplainExec) Schema() *expression.Schema {
return e.schema
}
// Next implements Execution Next interface.
func (e *ExplainExec) Next() (Row, error) {
if e.cursor >= len(e.rows) {
return nil, nil
}
row := e.rows[e.cursor]
e.cursor++
return row, nil
}
// Close implements the Executor Close interface.
func (e *ExplainExec) Close() error {
e.rows = nil
return nil
}