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// +build go1.8
package pq
import (
"context"
"database/sql/driver"
"errors"
)
// Implement the "QueryerContext" interface
func (cn *conn) QueryContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Rows, error) {
list := make([]driver.Value, len(args))
for i, nv := range args {
list[i] = nv.Value
}
var closed chan<- struct{}
if ctx.Done() != nil {
closed = watchCancel(ctx, cn.cancel)
}
r, err := cn.query(query, list)
if err != nil {
return nil, err
}
r.closed = closed
return r, nil
}
// Implement the "ExecerContext" interface
func (cn *conn) ExecContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Result, error) {
list := make([]driver.Value, len(args))
for i, nv := range args {
list[i] = nv.Value
}
if ctx.Done() != nil {
closed := watchCancel(ctx, cn.cancel)
defer close(closed)
}
return cn.Exec(query, list)
}
// Implement the "ConnBeginTx" interface
func (cn *conn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
if opts.Isolation != 0 {
return nil, errors.New("isolation levels not supported")
}
if opts.ReadOnly {
return nil, errors.New("read-only transactions not supported")
}
tx, err := cn.Begin()
if err != nil {
return nil, err
}
if ctx.Done() != nil {
cn.txnClosed = watchCancel(ctx, cn.cancel)
}
return tx, nil
}
func watchCancel(ctx context.Context, cancel func()) chan<- struct{} {
closed := make(chan struct{})
go func() {
select {
case <-ctx.Done():
cancel()
case <-closed:
}
}()
return closed
}
func (cn *conn) cancel() {
var err error
can := &conn{}
can.c, err = dial(cn.dialer, cn.opts)
if err != nil {
return
}
can.ssl(cn.opts)
defer can.errRecover(&err)
w := can.writeBuf(0)
w.int32(80877102) // cancel request code
w.int32(cn.processID)
w.int32(cn.secretKey)
can.sendStartupPacket(w)
_ = can.c.Close()
}
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