ctxutil.go

Documentation: database/sql

		 1  // Copyright 2016 The Go Authors. All rights reserved.
		 2  // Use of this source code is governed by a BSD-style
		 3  // license that can be found in the LICENSE file.
		 4  
		 5  package sql
		 6  
		 7  import (
		 8  	"context"
		 9  	"database/sql/driver"
		10  	"errors"
		11  )
		12  
		13  func ctxDriverPrepare(ctx context.Context, ci driver.Conn, query string) (driver.Stmt, error) {
		14  	if ciCtx, is := ci.(driver.ConnPrepareContext); is {
		15  		return ciCtx.PrepareContext(ctx, query)
		16  	}
		17  	si, err := ci.Prepare(query)
		18  	if err == nil {
		19  		select {
		20  		default:
		21  		case <-ctx.Done():
		22  			si.Close()
		23  			return nil, ctx.Err()
		24  		}
		25  	}
		26  	return si, err
		27  }
		28  
		29  func ctxDriverExec(ctx context.Context, execerCtx driver.ExecerContext, execer driver.Execer, query string, nvdargs []driver.NamedValue) (driver.Result, error) {
		30  	if execerCtx != nil {
		31  		return execerCtx.ExecContext(ctx, query, nvdargs)
		32  	}
		33  	dargs, err := namedValueToValue(nvdargs)
		34  	if err != nil {
		35  		return nil, err
		36  	}
		37  
		38  	select {
		39  	default:
		40  	case <-ctx.Done():
		41  		return nil, ctx.Err()
		42  	}
		43  	return execer.Exec(query, dargs)
		44  }
		45  
		46  func ctxDriverQuery(ctx context.Context, queryerCtx driver.QueryerContext, queryer driver.Queryer, query string, nvdargs []driver.NamedValue) (driver.Rows, error) {
		47  	if queryerCtx != nil {
		48  		return queryerCtx.QueryContext(ctx, query, nvdargs)
		49  	}
		50  	dargs, err := namedValueToValue(nvdargs)
		51  	if err != nil {
		52  		return nil, err
		53  	}
		54  
		55  	select {
		56  	default:
		57  	case <-ctx.Done():
		58  		return nil, ctx.Err()
		59  	}
		60  	return queryer.Query(query, dargs)
		61  }
		62  
		63  func ctxDriverStmtExec(ctx context.Context, si driver.Stmt, nvdargs []driver.NamedValue) (driver.Result, error) {
		64  	if siCtx, is := si.(driver.StmtExecContext); is {
		65  		return siCtx.ExecContext(ctx, nvdargs)
		66  	}
		67  	dargs, err := namedValueToValue(nvdargs)
		68  	if err != nil {
		69  		return nil, err
		70  	}
		71  
		72  	select {
		73  	default:
		74  	case <-ctx.Done():
		75  		return nil, ctx.Err()
		76  	}
		77  	return si.Exec(dargs)
		78  }
		79  
		80  func ctxDriverStmtQuery(ctx context.Context, si driver.Stmt, nvdargs []driver.NamedValue) (driver.Rows, error) {
		81  	if siCtx, is := si.(driver.StmtQueryContext); is {
		82  		return siCtx.QueryContext(ctx, nvdargs)
		83  	}
		84  	dargs, err := namedValueToValue(nvdargs)
		85  	if err != nil {
		86  		return nil, err
		87  	}
		88  
		89  	select {
		90  	default:
		91  	case <-ctx.Done():
		92  		return nil, ctx.Err()
		93  	}
		94  	return si.Query(dargs)
		95  }
		96  
		97  func ctxDriverBegin(ctx context.Context, opts *TxOptions, ci driver.Conn) (driver.Tx, error) {
		98  	if ciCtx, is := ci.(driver.ConnBeginTx); is {
		99  		dopts := driver.TxOptions{}
	 100  		if opts != nil {
	 101  			dopts.Isolation = driver.IsolationLevel(opts.Isolation)
	 102  			dopts.ReadOnly = opts.ReadOnly
	 103  		}
	 104  		return ciCtx.BeginTx(ctx, dopts)
	 105  	}
	 106  
	 107  	if opts != nil {
	 108  		// Check the transaction level. If the transaction level is non-default
	 109  		// then return an error here as the BeginTx driver value is not supported.
	 110  		if opts.Isolation != LevelDefault {
	 111  			return nil, errors.New("sql: driver does not support non-default isolation level")
	 112  		}
	 113  
	 114  		// If a read-only transaction is requested return an error as the
	 115  		// BeginTx driver value is not supported.
	 116  		if opts.ReadOnly {
	 117  			return nil, errors.New("sql: driver does not support read-only transactions")
	 118  		}
	 119  	}
	 120  
	 121  	if ctx.Done() == nil {
	 122  		return ci.Begin()
	 123  	}
	 124  
	 125  	txi, err := ci.Begin()
	 126  	if err == nil {
	 127  		select {
	 128  		default:
	 129  		case <-ctx.Done():
	 130  			txi.Rollback()
	 131  			return nil, ctx.Err()
	 132  		}
	 133  	}
	 134  	return txi, err
	 135  }
	 136  
	 137  func namedValueToValue(named []driver.NamedValue) ([]driver.Value, error) {
	 138  	dargs := make([]driver.Value, len(named))
	 139  	for n, param := range named {
	 140  		if len(param.Name) > 0 {
	 141  			return nil, errors.New("sql: driver does not support the use of Named Parameters")
	 142  		}
	 143  		dargs[n] = param.Value
	 144  	}
	 145  	return dargs, nil
	 146  }
	 147
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