storage: Add OfflineSession object to backend storage.

storage/sql/crud.go

@@ -624,6 +624,75 @@ func scanPassword(s scanner) (p storage.Password, err error) {
 	return p, nil
 }
 
+func (c *conn) CreateOfflineSessions(s storage.OfflineSessions) error {
+	_, err := c.Exec(`
+		insert into offline_session (
+			user_id, conn_id, refresh
+		)
+		values (
+			$1, $2, $3
+		);
+	`,
+		s.UserID, s.ConnID, encoder(s.Refresh),
+	)
+	if err != nil {
+		return fmt.Errorf("insert offline session: %v", err)
+	}
+	return nil
+}
+
+func (c *conn) UpdateOfflineSessions(userID string, connID string, updater func(s storage.OfflineSessions) (storage.OfflineSessions, error)) error {
+	return c.ExecTx(func(tx *trans) error {
+		s, err := getOfflineSessions(tx, userID, connID)
+		if err != nil {
+			return err
+		}
+
+		newSession, err := updater(s)
+		if err != nil {
+			return err
+		}
+		_, err = tx.Exec(`
+			update offline_session
+			set
+				refresh = $1
+			where user_id = $2 AND conn_id = $3;
+		`,
+			encoder(newSession.Refresh), s.UserID, s.ConnID,
+		)
+		if err != nil {
+			return fmt.Errorf("update offline session: %v", err)
+		}
+		return nil
+	})
+}
+
+func (c *conn) GetOfflineSessions(userID string, connID string) (storage.OfflineSessions, error) {
+	return getOfflineSessions(c, userID, connID)
+}
+
+func getOfflineSessions(q querier, userID string, connID string) (storage.OfflineSessions, error) {
+	return scanOfflineSessions(q.QueryRow(`
+		select
+			user_id, conn_id, refresh
+		from offline_session
+		where user_id = $1 AND conn_id = $2;
+		`, userID, connID))
+}
+
+func scanOfflineSessions(s scanner) (o storage.OfflineSessions, err error) {
+	err = s.Scan(
+		&o.UserID, &o.ConnID, decoder(&o.Refresh),
+	)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			return o, storage.ErrNotFound
+		}
+		return o, fmt.Errorf("select offline session: %v", err)
+	}
+	return o, nil
+}
+
 func (c *conn) DeleteAuthRequest(id string) error { return c.delete("auth_request", "id", id) }
 func (c *conn) DeleteAuthCode(id string) error    { return c.delete("auth_code", "id", id) }
 func (c *conn) DeleteClient(id string) error      { return c.delete("client", "id", id) }
@@ -632,6 +701,24 @@ func (c *conn) DeletePassword(email string) error {
 	return c.delete("password", "email", strings.ToLower(email))
 }
 
+func (c *conn) DeleteOfflineSessions(userID string, connID string) error {
+	result, err := c.Exec(`delete from offline_session where user_id = $1 AND conn_id = $2`, userID, connID)
+	if err != nil {
+		return fmt.Errorf("delete offline_session: user_id = %s, conn_id = %s", userID, connID)
+	}
+
+	// For now mandate that the driver implements RowsAffected. If we ever need to support
+	// a driver that doesn't implement this, we can run this in a transaction with a get beforehand.
+	n, err := result.RowsAffected()
+	if err != nil {
+		return fmt.Errorf("rows affected: %v", err)
+	}
+	if n < 1 {
+		return storage.ErrNotFound
+	}
+	return nil
+}
+
 // Do NOT call directly. Does not escape table.
 func (c *conn) delete(table, field, id string) error {
 	result, err := c.Exec(`delete from `+table+` where `+field+` = $1`, id)