dovecot-2.2: lib-imap-client: Allow reconnecting to IMAP server ...

[dovecot at dovecot.org]

details:   http://hg.dovecot.org/dovecot-2.2/rev/feef967b10fe
changeset: 19005:feef967b10fe
user:      Timo Sirainen <tss at iki.fi>
date:      Tue Aug 25 16:57:57 2015 +0300
description:
lib-imap-client: Allow reconnecting to IMAP server even if there had been no idle moments.

diffstat:

 src/lib-imap-client/imapc-client.c     |   8 ++++++++
 src/lib-imap-client/imapc-connection.c |  17 +++++++++++++++++
 src/lib-imap-client/imapc-connection.h |   1 +
 3 files changed, 26 insertions(+), 0 deletions(-)

diffs (87 lines):

diff -r e5bc6d90649b -r feef967b10fe src/lib-imap-client/imapc-client.c
--- a/src/lib-imap-client/imapc-client.c	Tue Aug 25 16:55:00 2015 +0300
+++ b/src/lib-imap-client/imapc-client.c	Tue Aug 25 16:57:57 2015 +0300
@@ -299,6 +299,7 @@
 	if (reply->state == IMAPC_COMMAND_STATE_OK) {
 		/* reopen the mailbox */
 		box->reopen_callback(box->reopen_context);
+		imapc_connection_set_reconnected(box->conn);
 	} else {
 		imapc_connection_abort_commands(box->conn, NULL, FALSE);
 	}
@@ -306,6 +307,9 @@
 
 bool imapc_client_mailbox_can_reconnect(struct imapc_client_mailbox *box)
 {
+	/* the reconnect_ok flag attempts to avoid infinite reconnection loops
+	   to a server that keeps disconnecting us (e.g. some of the commands
+	   we send keeps crashing it always) */
 	return box->reopen_callback != NULL && box->reconnect_ok;
 }
 
@@ -322,6 +326,9 @@
 		imapc_connection_connect(box->conn,
 					 imapc_client_reconnect_cb, box);
 	}
+	/* if we fail again, avoid reconnecting immediately. if the server is
+	   broken we could just get into an infinitely failing reconnection
+	   loop. */
 	box->reconnect_ok = FALSE;
 }
 
@@ -393,6 +400,7 @@
 			timeout_add_short(IMAPC_CLIENT_IDLE_SEND_DELAY_MSECS,
 					  imapc_client_mailbox_idle_send, box);
 	}
+	/* we're done with all work at this point. */
 	box->reconnect_ok = TRUE;
 }
 
diff -r e5bc6d90649b -r feef967b10fe src/lib-imap-client/imapc-connection.c
--- a/src/lib-imap-client/imapc-connection.c	Tue Aug 25 16:55:00 2015 +0300
+++ b/src/lib-imap-client/imapc-connection.c	Tue Aug 25 16:57:57 2015 +0300
@@ -110,6 +110,7 @@
 	ARRAY_TYPE(imapc_command) cmd_send_queue;
 	/* commands that have been sent, waiting for their tagged reply */
 	ARRAY_TYPE(imapc_command) cmd_wait_list;
+	unsigned int reconnect_command_count;
 
 	unsigned int ips_count, prev_connect_idx;
 	struct ip_addr *ips;
@@ -1303,6 +1304,16 @@
 		imapc_connection_unselect(conn->selected_box);
 	}
 
+	if (conn->reconnect_command_count > 0) {
+		if (--conn->reconnect_command_count == 0) {
+			/* we've received replies for all the commands started
+			   before reconnection. if we get disconnected now, we
+			   can safely reconnect without worrying about infinite
+			   reconnect loops. */
+			if (conn->selected_box != NULL)
+				conn->selected_box->reconnect_ok = TRUE;
+		}
+	}
 	imapc_connection_input_reset(conn);
 	imapc_command_reply_free(cmd, &reply);
 	imapc_command_send_more(conn);
@@ -2216,3 +2227,9 @@
 	cmd->idle = TRUE;
 	imapc_command_send(cmd, "IDLE");
 }
+
+void imapc_connection_set_reconnected(struct imapc_connection *conn)
+{
+	conn->reconnect_command_count = array_count(&conn->cmd_wait_list) +
+		array_count(&conn->cmd_send_queue);
+}
diff -r e5bc6d90649b -r feef967b10fe src/lib-imap-client/imapc-connection.h
--- a/src/lib-imap-client/imapc-connection.h	Tue Aug 25 16:55:00 2015 +0300
+++ b/src/lib-imap-client/imapc-connection.h	Tue Aug 25 16:57:57 2015 +0300
@@ -52,5 +52,6 @@
 imapc_connection_get_mailbox(struct imapc_connection *conn);
 
 void imapc_connection_idle(struct imapc_connection *conn);
+void imapc_connection_set_reconnected(struct imapc_connection *conn);
 
 #endif