45 lines
2.0 KiB
Go
45 lines
2.0 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 sqlexec
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import (
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"github.com/pingcap/tidb/context"
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"github.com/pingcap/tidb/rset"
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)
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// RestrictedSQLExecutorKeyType is a dummy type to avoid naming collision in session.
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type RestrictedSQLExecutorKeyType struct{}
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// String implements Stringer interface.
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func (k *RestrictedSQLExecutorKeyType) String() string {
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return "restricted_sql_executor"
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}
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// RestrictedSQLExecutor is an interface provides executing restricted sql statement.
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// Why we need this interface?
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// When we execute some management statements, we need to operate system tables.
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// For example when executing create user statement, we need to check if the user already
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// exists in the mysql.User table and insert a new row if not exists. In this case, we need
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// a convenience way to manipulate system tables. The most simple way is executing sql statement.
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// In order to execute sql statement in stmts package, we add this interface to solve dependence problem.
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// And in the same time, we do not want this interface becomes a general way to run sql statement.
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// We hope this could be used with some restrictions such as only allowing system tables as target,
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// do not allowing recursion call.
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// For more infomation please refer to the comments in session.ExecRestrictedSQL().
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// This is implemented in session.go.
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type RestrictedSQLExecutor interface {
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// ExecRestrictedSQL run sql statement in ctx with some restriction.
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ExecRestrictedSQL(ctx context.Context, sql string) (rset.Recordset, error)
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}
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