From 7435dc6d1d37bf65e146b27d669f71b3fc5efa69 Mon Sep 17 00:00:00 2001
From: Lefteris Chatzimparmpas <lefcha@fastmail.net>
Date: Mon, 27 Feb 2012 01:17:02 +0100
Subject: [PATCH] Add support to recover when BYE is received

Previously only network errors could cause a restoration of a session,
but now a BYE response sent by the server can also trigger it.

An option has been also added to control if and when the recover
function will be called.
---
 doc/imapfilter_config.5 | 15 ++++++++++++++-
 src/imapfilter.h        |  2 +-
 src/lua.c               | 20 ++++++++++++++++++++
 src/request.c           | 30 +++++++++++++++++-------------
 4 files changed, 52 insertions(+), 15 deletions(-)

diff --git a/doc/imapfilter_config.5 b/doc/imapfilter_config.5
index 26055fb..00460db 100644
--- a/doc/imapfilter_config.5
+++ b/doc/imapfilter_config.5
@@ -1,4 +1,4 @@
-.Dd February 19, 2012
+.Dd February 26, 2012
 .Dt IMAPFILTER_CONFIG 5
 .Os
 .Sh NAME
@@ -155,6 +155,19 @@ personal namespace mailboxes).  This variable takes
 .Vt boolean
 as a value.  Default is
 .Dq true .
+.It Va recover
+With this option it is possible to control the recovery functionality, which
+restores a session (the connection to the server and state at the time), after
+some unexpected event took place.  Currently there are two type of events that
+can cause a session to be terminated: network errors and the IMAP BYE response
+that the server can send anytime.  When this option is set to
+.Dq all ,
+both types of events trigger the recovery function, when it is set to
+.Dq errors ,
+only network errors trigger it, and when it is set to
+.Dq none ,
+it is never triggered.  Default is
+.Dq all .
 .It Va starttls
 When this option is enabled and the server supports the IMAP STARTTLS
 extension, a TLS connection will be negotiated with the mail server in the
diff --git a/src/imapfilter.h b/src/imapfilter.h
index 9b964e7..18d3f45 100644
--- a/src/imapfilter.h
+++ b/src/imapfilter.h
@@ -117,7 +117,7 @@ const char *get_option_string(const char *opt);
 
 int set_table_boolean(const char *key, int value);
 int set_table_number(const char *key, lua_Number value);
-int set_table_lightuserdata(const char *key, void *value);
+int set_table_string(const char *key, const char *value);
 
 /*	memory.c	*/
 void *xmalloc(size_t size);
diff --git a/src/lua.c b/src/lua.c
index bbef83a..706f4fc 100644
--- a/src/lua.c
+++ b/src/lua.c
@@ -113,6 +113,7 @@ init_options(void)
 	set_table_boolean("expunge", 1);
 	set_table_number("keepalive", 29);
 	set_table_boolean("namespace", 1);
+	set_table_string("recover", "all");
 	set_table_boolean("starttls", 1);
 	set_table_boolean("subscribe", 0);
 	set_table_number("timeout", 60);
@@ -194,6 +195,9 @@ get_option_string(const char *opt)
 	s = lua_tostring(lua, -1);
 	lua_pop(lua, 2);
 
+	if (!s)
+		return "";
+
 	return s;
 }
 
@@ -226,3 +230,19 @@ set_table_number(const char *key, lua_Number value)
 
 	return 0;
 }
+
+/*
+ * Set a table's element value to the specified string.
+ */
+int
+set_table_string(const char *key, const char *value)
+{
+
+	lua_pushstring(lua, key);
+	lua_pushstring(lua, value);
+	lua_settable(lua, -3);
+
+	return 0;
+}
+
+
diff --git a/src/request.c b/src/request.c
index 6c6fc2c..288c4f7 100644
--- a/src/request.c
+++ b/src/request.c
@@ -21,19 +21,23 @@ int send_request(session *ssn, const char *fmt,...);
 int send_continuation(session *ssn, const char *data, size_t len);
 
 
-#define TRY(F)								     \
-	switch ((F)) {							     \
-	case -1:							     \
-		if (request_login(&ssn, NULL, NULL, NULL, NULL, NULL) != -1) \
-			return STATUS_NONE;				     \
-		else							     \
-			return -1;					     \
-		break;							     \
-	case STATUS_BYE:						     \
-		close_connection(ssn);					     \
-		session_destroy(ssn);					     \
-		return -1;						     \
-		break;							     \
+#define TRY(F)								       \
+	switch ((F)) {							       \
+	case -1:							       \
+		if ((!strcasecmp(get_option_string("recover"), "all") ||       \
+		    !strcasecmp(get_option_string("recover"), "errors")) &&    \
+		    request_login(&ssn, NULL, NULL, NULL, NULL, NULL) != -1)   \
+			return STATUS_NONE;				       \
+		return -1;						       \
+	case STATUS_BYE:						       \
+		close_connection(ssn);					       \
+		if (!strcasecmp(get_option_string("recover"), "all")) {	       \
+			if (request_login(&ssn, NULL, NULL, NULL, NULL,	       \
+			    NULL) != -1)				       \
+				return STATUS_NONE;			       \
+		} else							       \
+			session_destroy(ssn);				       \
+		return -1;						       \
 	}