maddy

 1/*
 2Maddy Mail Server - Composable all-in-one email server.
 3Copyright © 2019-2020 Max Mazurov <fox.cpp@disroot.org>, Maddy Mail Server contributors
 4
 5This program is free software: you can redistribute it and/or modify
 6it under the terms of the GNU General Public License as published by
 7the Free Software Foundation, either version 3 of the License, or
 8(at your option) any later version.
 9
10This program is distributed in the hope that it will be useful,
11but WITHOUT ANY WARRANTY; without even the implied warranty of
12MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13GNU General Public License for more details.
14
15You should have received a copy of the GNU General Public License
16along with this program.  If not, see <https://www.gnu.org/licenses/>.
17*/
18
19package updatepipe
20
21type BackendMode int
22
23const (
24	// ModeReplicate configures backend to both send and receive updates over
25	// the pipe.
26	ModeReplicate BackendMode = iota
27
28	// ModePush configures backend to send updates over the pipe only.
29	//
30	// If EnableUpdatePipe(ModePush) is called for backend, its Updates()
31	// channel will never receive any updates.
32	ModePush BackendMode = iota
33)
34
35// The Backend interface is implemented by storage backends that support both
36// updates serialization using the internal updatepipe.P implementation.
37// To activate this implementation, EnableUpdatePipe should be called.
38type Backend interface {
39	// EnableUpdatePipe enables the internal update pipe implementation.
40	// The mode argument selects the pipe behavior. EnableUpdatePipe must be
41	// called before the first call to the Updates() method.
42	//
43	// This method is idempotent. All calls after a successful one do nothing.
44	EnableUpdatePipe(mode BackendMode) error
45}