From 4818cf555141d83b0d8414c86c3b7aef26286dd3 Mon Sep 17 00:00:00 2001 From: "Danilo M." Date: Thu, 24 Sep 2026 16:36:25 +0200 Subject: feat: write calendar files atomically, refusing stale ones --- src/calendarwriter.h | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 src/calendarwriter.h (limited to 'src/calendarwriter.h') diff --git a/src/calendarwriter.h b/src/calendarwriter.h new file mode 100644 index 0000000..0bcca09 --- /dev/null +++ b/src/calendarwriter.h @@ -0,0 +1,43 @@ +/* + * qtmaildir - a Qt6 mail client for notmuch-indexed Maildirs + * Copyright (C) 2026 Danilo M. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#pragma once + +#include +#include + +#include + +/// Every write to the calendar vdir goes through here. +/// +/// One function covers create, edit, delete and every undo of those, because +/// each is the same act: the file must currently be X, and must become Y, +/// where either may be "absent". vdirsyncer writes the same files from cron, +/// so "must currently be X" is the stale check that stops a save from +/// silently discarding what a sync just pulled. +namespace CalendarWriter { + +enum class Result { Ok, Stale, IoError }; + +/// `expected` nullopt: the file must not exist. `newText` nullopt: delete it. +/// A write goes to a hidden temporary in the same directory and is renamed +/// into place, so vdirsyncer, which lists only *.ics, never reads half a file. +Result replace(const QString &path, const std::optional &expected, + const std::optional &newText, QString *error); + +} // namespace CalendarWriter -- cgit v1.2.3