vitess.io/vitess@v0.16.2/go/vt/vtgate/engine/show_exec.go (about)

     1  /*
     2  Copyright 2022 The Vitess Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package engine
    18  
    19  import (
    20  	"context"
    21  
    22  	"vitess.io/vitess/go/sqltypes"
    23  	"vitess.io/vitess/go/vt/proto/query"
    24  	"vitess.io/vitess/go/vt/sqlparser"
    25  )
    26  
    27  var _ Primitive = (*ShowExec)(nil)
    28  
    29  // ShowExec is a primitive to call into executor via vcursor.
    30  type ShowExec struct {
    31  	Command    sqlparser.ShowCommandType
    32  	ShowFilter *sqlparser.ShowFilter
    33  
    34  	noInputs
    35  	noTxNeeded
    36  }
    37  
    38  func (s *ShowExec) RouteType() string {
    39  	return "ShowExec"
    40  }
    41  
    42  func (s *ShowExec) GetKeyspaceName() string {
    43  	return ""
    44  }
    45  
    46  func (s *ShowExec) GetTableName() string {
    47  	return ""
    48  }
    49  
    50  func (s *ShowExec) GetFields(ctx context.Context, vcursor VCursor, bindVars map[string]*query.BindVariable) (*sqltypes.Result, error) {
    51  	qr, err := s.TryExecute(ctx, vcursor, bindVars, true)
    52  	if err != nil {
    53  		return nil, err
    54  	}
    55  	qr.Rows = nil
    56  	return qr, nil
    57  }
    58  
    59  func (s *ShowExec) TryExecute(ctx context.Context, vcursor VCursor, bindVars map[string]*query.BindVariable, wantfields bool) (*sqltypes.Result, error) {
    60  	return vcursor.ShowExec(ctx, s.Command, s.ShowFilter)
    61  }
    62  
    63  func (s *ShowExec) TryStreamExecute(ctx context.Context, vcursor VCursor, bindVars map[string]*query.BindVariable, wantfields bool, callback func(*sqltypes.Result) error) error {
    64  	qr, err := s.TryExecute(ctx, vcursor, bindVars, wantfields)
    65  	if err != nil {
    66  		return err
    67  	}
    68  	return callback(qr)
    69  }
    70  
    71  func (s *ShowExec) description() PrimitiveDescription {
    72  	other := map[string]any{}
    73  	if s.ShowFilter != nil {
    74  		other["Filter"] = sqlparser.String(s.ShowFilter)
    75  	}
    76  	return PrimitiveDescription{
    77  		OperatorType: "ShowExec",
    78  		Variant:      s.Command.ToString(),
    79  		Other:        other,
    80  	}
    81  }