open-consul/vendor/github.com/SAP/go-hdb/driver/driver_future.go

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2018-06-21 14:49:35 +00:00
// +build future
/*
Copyright 2018 SAP SE
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,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package driver
import (
"context"
//"database/sql"
"database/sql/driver"
"github.com/SAP/go-hdb/driver/sqltrace"
p "github.com/SAP/go-hdb/internal/protocol"
)
// database connection
func (c *conn) PrepareContext(ctx context.Context, query string) (stmt driver.Stmt, err error) {
if c.session.IsBad() {
return nil, driver.ErrBadConn
}
done := make(chan struct{})
go func() {
var (
qt p.QueryType
id uint64
prmFieldSet *p.ParameterFieldSet
resultFieldSet *p.ResultFieldSet
)
qt, id, prmFieldSet, resultFieldSet, err = c.session.Prepare(query)
if err != nil {
goto done
}
select {
default:
case <-ctx.Done():
return
}
stmt, err = newStmt(qt, c.session, query, id, prmFieldSet, resultFieldSet)
done:
close(done)
}()
select {
case <-ctx.Done():
return nil, ctx.Err()
case <-done:
return stmt, err
}
}
// QueryContext implements the database/sql/driver/QueryerContext interface.
func (c *conn) QueryContext(ctx context.Context, query string, args []driver.NamedValue) (rows driver.Rows, err error) {
if c.session.IsBad() {
return nil, driver.ErrBadConn
}
if len(args) != 0 {
return nil, driver.ErrSkip //fast path not possible (prepare needed)
}
// direct execution of call procedure
// - returns no parameter metadata (sps 82) but only field values
// --> let's take the 'prepare way' for stored procedures
// if checkCallProcedure(query) {
// return nil, driver.ErrSkip
// }
sqltrace.Traceln(query)
done := make(chan struct{})
go func() {
var (
id uint64
resultFieldSet *p.ResultFieldSet
fieldValues *p.FieldValues
attributes p.PartAttributes
)
id, resultFieldSet, fieldValues, attributes, err = c.session.QueryDirect(query)
if err != nil {
goto done
}
select {
default:
case <-ctx.Done():
return
}
if id == 0 { // non select query
rows = noResult
} else {
rows, err = newQueryResult(c.session, id, resultFieldSet, fieldValues, attributes)
}
done:
close(done)
}()
select {
case <-ctx.Done():
return nil, ctx.Err()
case <-done:
return rows, err
}
}
//statement
func (s *stmt) QueryContext(ctx context.Context, args []driver.NamedValue) (rows driver.Rows, err error) {
if s.session.IsBad() {
return nil, driver.ErrBadConn
}
done := make(chan struct{})
go func() {
rows, err = s.defaultQuery(ctx, args)
close(done)
}()
select {
case <-ctx.Done():
return nil, ctx.Err()
case <-done:
return rows, err
}
}
func (s *stmt) defaultQuery(ctx context.Context, args []driver.NamedValue) (driver.Rows, error) {
sqltrace.Tracef("%s %v", s.query, args)
rid, values, attributes, err := s.session.Query(s.id, s.prmFieldSet, s.resultFieldSet, args)
if err != nil {
return nil, err
}
select {
default:
case <-ctx.Done():
return nil, ctx.Err()
}
if rid == 0 { // non select query
return noResult, nil
}
return newQueryResult(s.session, rid, s.resultFieldSet, values, attributes)
}