github.com/dolthub/dolt/go@v0.40.5-0.20240520175717-68db7794bea6/libraries/doltcore/mvdata/engine_table_reader.go (about)

     1  // Copyright 2021 Dolthub, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package mvdata
    16  
    17  import (
    18  	"context"
    19  	"fmt"
    20  
    21  	sqle "github.com/dolthub/go-mysql-server"
    22  	"github.com/dolthub/go-mysql-server/sql"
    23  	"github.com/dolthub/go-mysql-server/sql/plan"
    24  	"github.com/dolthub/go-mysql-server/sql/planbuilder"
    25  
    26  	"github.com/dolthub/dolt/go/cmd/dolt/commands/engine"
    27  	"github.com/dolthub/dolt/go/libraries/doltcore/doltdb"
    28  	"github.com/dolthub/dolt/go/libraries/doltcore/env"
    29  	"github.com/dolthub/dolt/go/libraries/doltcore/row"
    30  	"github.com/dolthub/dolt/go/libraries/doltcore/schema"
    31  	dsqle "github.com/dolthub/dolt/go/libraries/doltcore/sqle"
    32  	"github.com/dolthub/dolt/go/libraries/doltcore/sqle/dsess"
    33  	"github.com/dolthub/dolt/go/libraries/doltcore/sqle/sqlutil"
    34  )
    35  
    36  type sqlEngineTableReader struct {
    37  	se     *engine.SqlEngine
    38  	sqlCtx *sql.Context
    39  
    40  	sch  schema.Schema
    41  	iter sql.RowIter
    42  }
    43  
    44  func NewSqlEngineReader(ctx context.Context, dEnv *env.DoltEnv, tableName string) (*sqlEngineTableReader, error) {
    45  	mrEnv, err := env.MultiEnvForDirectory(ctx, dEnv.Config.WriteableConfig(), dEnv.FS, dEnv.Version, dEnv)
    46  	if err != nil {
    47  		return nil, err
    48  	}
    49  
    50  	config := &engine.SqlEngineConfig{
    51  		ServerUser: "root",
    52  		Autocommit: true,
    53  	}
    54  	se, err := engine.NewSqlEngine(
    55  		ctx,
    56  		mrEnv,
    57  		config,
    58  	)
    59  	if err != nil {
    60  		return nil, err
    61  	}
    62  
    63  	sqlCtx, err := se.NewLocalContext(ctx)
    64  	if err != nil {
    65  		return nil, err
    66  	}
    67  	sqlCtx.SetCurrentDatabase(mrEnv.GetFirstDatabase())
    68  
    69  	sqlEngine := se.GetUnderlyingEngine()
    70  	binder := planbuilder.New(sqlCtx, sqlEngine.Analyzer.Catalog, sqlEngine.Parser)
    71  	ret, _, _, err := binder.Parse(fmt.Sprintf("show create table `%s`", tableName), false)
    72  	if err != nil {
    73  		return nil, err
    74  	}
    75  
    76  	create, ok := ret.(*plan.ShowCreateTable)
    77  	if !ok {
    78  		return nil, fmt.Errorf("expected *plan.ShowCreate table, found %T", ret)
    79  	}
    80  
    81  	_, iter, err := se.Query(sqlCtx, fmt.Sprintf("SELECT * FROM `%s`", tableName))
    82  	if err != nil {
    83  		return nil, err
    84  	}
    85  
    86  	root, err := dEnv.WorkingRoot(ctx)
    87  	if err != nil {
    88  		return nil, err
    89  	}
    90  
    91  	doltSchema, err := sqlutil.ToDoltSchema(ctx, root, tableName, create.PrimaryKeySchema, nil, sql.Collation_Default)
    92  	if err != nil {
    93  		return nil, err
    94  	}
    95  
    96  	return &sqlEngineTableReader{
    97  		se:     se,
    98  		sqlCtx: sqlCtx,
    99  
   100  		sch:  doltSchema,
   101  		iter: iter,
   102  	}, nil
   103  }
   104  
   105  // Used by Dolthub API
   106  func NewSqlEngineTableReaderWithEngine(sqlCtx *sql.Context, se *sqle.Engine, db dsqle.Database, root doltdb.RootValue, tableName string) (*sqlEngineTableReader, error) {
   107  	sch, iter, err := se.Query(sqlCtx, fmt.Sprintf("SELECT * FROM `%s`", tableName))
   108  	if err != nil {
   109  		return nil, err
   110  	}
   111  
   112  	doltSchema, err := sqlutil.ToDoltSchema(sqlCtx, root, tableName, sql.NewPrimaryKeySchema(sch), nil, sql.Collation_Default)
   113  	if err != nil {
   114  		return nil, err
   115  	}
   116  
   117  	return &sqlEngineTableReader{
   118  		se:     engine.NewRebasedSqlEngine(se, map[string]dsess.SqlDatabase{db.Name(): db}),
   119  		sqlCtx: sqlCtx,
   120  
   121  		sch:  doltSchema,
   122  		iter: iter,
   123  	}, nil
   124  }
   125  
   126  func (s *sqlEngineTableReader) GetSchema() schema.Schema {
   127  	return s.sch
   128  }
   129  
   130  func (s *sqlEngineTableReader) ReadRow(ctx context.Context) (row.Row, error) {
   131  	panic("deprecated")
   132  }
   133  
   134  func (s *sqlEngineTableReader) ReadSqlRow(ctx context.Context) (sql.Row, error) {
   135  	next, err := s.iter.Next(s.sqlCtx)
   136  	if err != nil {
   137  		return nil, err
   138  	}
   139  
   140  	return next, nil
   141  }
   142  
   143  func (s *sqlEngineTableReader) Close(ctx context.Context) error {
   144  	return s.iter.Close(s.sqlCtx)
   145  }