dsync: Add per-mailbox sync lock that is always used. Both importing and exporting gets the lock before they even sync the mailbox. The lock is kept until the import/export finishes. This guarantees that no matter how dsync is run, two dsyncs can't be working on the same mailbox at the same time. This lock is in addition to the optional per-user lock enabled by the -l parameter. If the -l parameter is used, the same lock timeout is used for the per-mailbox lock. Otherwise 30s timeout is used. This should help to avoid email duplication when replication is enabled for public namespaces, and maybe in some other rare situations as well.

#ifndef CLIENT_AUTHENTICATE_H
#define CLIENT_AUTHENTICATE_H

void pop3_client_auth_result(struct client *client,
			     enum client_auth_result result,
			     const struct client_auth_reply *reply,
			     const char *text);

bool cmd_capa(struct pop3_client *client, const char *args);
bool cmd_user(struct pop3_client *client, const char *args);
bool cmd_pass(struct pop3_client *client, const char *args);
bool cmd_auth(struct pop3_client *client, const char *args);
bool cmd_apop(struct pop3_client *client, const char *args);

#endif