func ctxDriverBegin(ctx context.Context, ci driver.Conn) (driver.Tx, error) {
if ciCtx, is := ci.(driver.ConnBeginContext); is {
return ciCtx.BeginContext(ctx)
}
if ctx.Done() == context.Background().Done() {
return ci.Begin()
}
// Check the transaction level in ctx. If set and non-default
// then return an error here as the BeginContext driver value is not supported.
if level, ok := driver.IsolationFromContext(ctx); ok && level != driver.IsolationLevel(LevelDefault) {
return nil, errors.New("sql: driver does not support non-default isolation level")
}
// Check for a read-only parameter in ctx. If a read-only transaction is
// requested return an error as the BeginContext driver value is not supported.
if ro := driver.ReadOnlyFromContext(ctx); ro {
return nil, errors.New("sql: driver does not support read-only transactions")
}
txi, err := ci.Begin()
if err == nil {
select {
default:
case <-ctx.Done():
txi.Rollback()
return nil, ctx.Err()
}
}
return txi, err
}
func ctxDriverBegin(ctx context.Context, ci driver.Conn) (driver.Tx, error) {
if ciCtx, is := ci.(driver.ConnBeginContext); is {
return ciCtx.BeginContext(ctx)
}
if ctx.Done() == context.Background().Done() {
return ci.Begin()
}
// Check the transaction level in ctx. If set and non-default
// then return an error here as the BeginContext driver value is not supported.
if level, ok := driver.IsolationFromContext(ctx); ok && level != driver.IsolationLevel(LevelDefault) {
return nil, errors.New("sql: driver does not support non-default isolation level")
}
// Check for a read-only parameter in ctx. If a read-only transaction is
// requested return an error as the BeginContext driver value is not supported.
if ro := driver.ReadOnlyFromContext(ctx); ro {
return nil, errors.New("sql: driver does not support read-only transactions")
}
type R struct {
err error
panic interface{}
txi driver.Tx
}
rc := make(chan R, 1)
go func() {
r := R{}
defer func() {
if v := recover(); v != nil {
r.panic = v
}
rc <- r
}()
r.txi, r.err = ci.Begin()
}()
select {
case <-ctx.Done():
go func() {
<-rc
close(rc)
}()
return nil, ctx.Err()
case r := <-rc:
if r.panic != nil {
panic(r.panic)
}
return r.txi, r.err
}
}