pgtype.OID type should only be used for scanning and encoding values

It was a mistake to use it in other contexts. This made interop
difficult between pacakges that depended on pgtype such as pgx and
packages that did not like pgconn and pgproto3. In particular this was
awkward for prepared statements.

This is preparation for removing pgx.PreparedStatement in favor of
pgconn.PreparedStatement.

large_objects.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"io"
 
-	"github.com/jackc/pgtype"
 	errors "golang.org/x/xerrors"
 )
 
@@ -24,7 +23,7 @@ const (
 )
 
 // Create creates a new large object. If oid is zero, the server assigns an unused OID.
-func (o *LargeObjects) Create(ctx context.Context, oid pgtype.OID) (pgtype.OID, error) {
+func (o *LargeObjects) Create(ctx context.Context, oid uint32) (uint32, error) {
 	_, err := o.tx.Prepare(ctx, "lo_create", "select lo_create($1)")
 	if err != nil {
 		return 0, err
@@ -36,7 +35,7 @@ func (o *LargeObjects) Create(ctx context.Context, oid pgtype.OID) (pgtype.OID,
 
 // Open opens an existing large object with the given mode. ctx will also be used for all operations on the opened large
 // object.
-func (o *LargeObjects) Open(ctx context.Context, oid pgtype.OID, mode LargeObjectMode) (*LargeObject, error) {
+func (o *LargeObjects) Open(ctx context.Context, oid uint32, mode LargeObjectMode) (*LargeObject, error) {
 	_, err := o.tx.Prepare(ctx, "lo_open", "select lo_open($1, $2)")
 	if err != nil {
 		return nil, err
@@ -51,7 +50,7 @@ func (o *LargeObjects) Open(ctx context.Context, oid pgtype.OID, mode LargeObjec
 }
 
 // Unlink removes a large object from the database.
-func (o *LargeObjects) Unlink(ctx context.Context, oid pgtype.OID) error {
+func (o *LargeObjects) Unlink(ctx context.Context, oid uint32) error {
 	_, err := o.tx.Prepare(ctx, "lo_unlink", "select lo_unlink($1)")
 	if err != nil {
 		return err