// GoToSocial // Copyright (C) GoToSocial Authors admin@gotosocial.org // SPDX-License-Identifier: AGPL-3.0-or-later // // This program is free software: you can redistribute it and/or modify // it under the terms of the GNU Affero General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // This program is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU Affero General Public License for more details. // // You should have received a copy of the GNU Affero General Public License // along with this program. If not, see <http://www.gnu.org/licenses/>. package federatingdb import ( "context" "errors" "net/url" ) // Lock takes a lock for the object at the specified id. If an error // is returned, the lock must not have been taken. // // The lock must be able to succeed for an id that does not exist in // the database. This means acquiring the lock does not guarantee the // entry exists in the database. // // Locks are encouraged to be lightweight and in the Go layer, as some // processes require tight loops acquiring and releasing locks. // // Used to ensure race conditions in multiple requests do not occur. func (f *federatingDB) Lock(c context.Context, id *url.URL) (func(), error) { if id == nil { return nil, errors.New("Lock: id was nil") } unlock := f.locks.Lock(id.String()) return unlock, nil }