Deal with X-IMAP header properly.

svn path=/trunk/; revision=1244

7 files changed, 53 insertions, 4 deletions

diff --git a/NEWS b/NEWS
index be19e8c0..ad54d873 100644
--- a/NEWS
+++ b/NEWS
@@ -23,6 +23,10 @@
 ------------------------------------------------------------------------------
 fetchmail-4.0.8 ()
 * Fixed core dump bug in UID handling introduced by the 4.0.6 change.
+* Retrieval code for POP3 & older IMAP versions now skips X-IMAP message
+  used by UW IMAP4rev1 server to store UIDs.
+
+There are 260 people on the fetchmail-friends list.
 
 fetchmail-4.0.7 (Tue Aug  5 22:47:11 EDT 1997)
 * Fixed a minor bug in handling of DNS errors in multidrop mode.
diff --git a/driver.c b/driver.c
index 224a941c..853f5bfa 100644
--- a/driver.c
+++ b/driver.c
@@ -502,12 +502,13 @@ static int stuffline(struct query *ctl, char *buf, flag delimited)
     return(n);
 }
 
-static int readheaders(sock, len, ctl, realname)
+static int readheaders(sock, len, ctl, realname, num)
 /* read message headers and ship to SMTP or MDA */
 int sock;		/* to which the server is connected */
 long len;		/* length of message */
 struct query *ctl;	/* query control record */
 char *realname;		/* real name of host */
+int num;		/* index of message */
 {
     char buf[MSGBUFSIZE+1], return_path[MSGBUFSIZE+1]; 
     int	from_offs, ctt_offs, env_offs, addressoffs[128], next_address;
@@ -585,6 +586,10 @@ char *realname;		/* real name of host */
 	    break;
 	}
      
+	/* maybe this is a special message that holds mailbox annotations? */ 
+	if (protocol->retain_hdr && protocol->retain_hdr(num, line))
+	    return(PS_RETAINED);
+
 	/*
 	 * This code prevents fetchmail from becoming an accessory after
 	 * the fact to upstream sendmails with the `E' option on.  This
@@ -1536,6 +1541,7 @@ const struct method *proto;	/* protocol method table */
 			&& (ctl->fetchall || force_retrieval || !(protocol->is_old && (protocol->is_old)(sock,ctl,num)));
 		    flag suppress_delete = FALSE;
 		    flag suppress_forward = FALSE;
+		    flag retained = FALSE;
 
 		    /* we may want to reject this message if it's old */
 		    if (!fetch_it)
@@ -1581,8 +1587,10 @@ const struct method *proto;	/* protocol method table */
 			 * Read the message headers and ship them to the
 			 * output sink.  
 			 */
-			ok = readheaders(sock, len, ctl, realname);
-			if (ok == PS_TRANSIENT)
+			ok = readheaders(sock, len, ctl, realname, num);
+			if (ok == PS_RETAINED)
+			    suppress_forward = retained = TRUE;
+			else if (ok == PS_TRANSIENT)
 			    suppress_delete = suppress_forward = TRUE;
 			else if (ok == PS_REFUSED)
 			    suppress_forward = TRUE;
@@ -1679,7 +1687,12 @@ const struct method *proto;	/* protocol method table */
 		     */
 
 		    /* maybe we delete this message now? */
-		    if (protocol->delete
+		    if (retained)
+		    {
+			if (outlevel > O_SILENT) 
+			    error_complete(0, 0, " retained");
+		    }
+		    else if (protocol->delete
 			&& !suppress_delete
 			&& (fetch_it ? !ctl->keep : ctl->flush))
 		    {
diff --git a/etrn.c b/etrn.c
index c0f6fea1..36a2e037 100644
--- a/etrn.c
+++ b/etrn.c
@@ -163,6 +163,7 @@ const static struct method etrn =
     NULL,		/* no way to fetch body */
     NULL,		/* no message trailer */
     NULL,		/* how to delete a message */
+    NULL,		/* no retained-header check */
     "QUIT",		/* the ETRN exit command */
 };
 
diff --git a/fetchmail.h b/fetchmail.h
index f5632c2d..0db3f4b3 100644
--- a/fetchmail.h
+++ b/fetchmail.h
@@ -42,6 +42,7 @@
 #define		PS_UNDEFINED	11	/* something I hadn't thought of */
 #define		PS_TRANSIENT	12	/* transient failure (internal use) */
 #define		PS_REFUSED	13	/* mail refused (internal use) */
+#define		PS_RETAINED	24	/* message retained (internal use) */
 
 /* output noise level */
 #define         O_SILENT	0	/* mute, max squelch, etc. */
@@ -168,6 +169,7 @@ struct method
     int (*fetch_body)();	/* fetch a given message */
     int (*trail)();		/* eat trailer of a message */
     int (*delete)();		/* delete method */
+    flag (*retain_hdr)();	/* if this returns TRUE, retain message */
     char *exit_cmd;		/* exit command */
 };
 
diff --git a/imap.c b/imap.c
index 3234b3b5..f1d5a225 100644
--- a/imap.c
+++ b/imap.c
@@ -620,6 +620,19 @@ static int imap_delete(int sock, struct query *ctl, int number)
     return(PS_SUCCESS);
 }
 
+static flag imap_retain_check(int num, char *buf)
+/* is this a special message that should be retained? */
+{
+    /*
+     * The University of Washington IMAP server (the reference
+     * implementation of IMAP4 written by Mark Crispin) relies
+     * on being able to keep base-UID information in a special
+     * message at the head of the mailbox.  This message should
+     * neither be deleted nor forwarded.
+     */
+    return (num == 1 && !strncasecmp(buf, "X-IMAP:", 7));
+}
+
 const static struct method imap =
 {
     "IMAP",		/* Internet Message Access Protocol */
@@ -636,6 +649,7 @@ const static struct method imap =
     imap_fetch_body,	/* request given message body */
     imap_trail,		/* eat message trailer */
     imap_delete,	/* delete the message */
+    imap_retain_check,	/* leave this message alone? */
     "LOGOUT",		/* the IMAP exit command */
 };
 
diff --git a/pop2.c b/pop2.c
index dbb37284..170c07ac 100644
--- a/pop2.c
+++ b/pop2.c
@@ -130,6 +130,7 @@ const static struct method pop2 =
     NULL,				/* no way to fetch body alone */
     pop2_trail,				/* eat message trailer */
     NULL,				/* no POP2 delete method */
+    NULL,				/* no retained-header check */
     "QUIT",				/* the POP2 exit command */
 };
 
diff --git a/pop3.c b/pop3.c
index 59f1da7e..e5e26299 100644
--- a/pop3.c
+++ b/pop3.c
@@ -342,6 +342,19 @@ static int pop3_delete(int sock, struct query *ctl, int number)
     return(gen_transact(sock, "DELE %d", number));
 }
 
+static flag pop3_retain_check(int num, char *buf)
+/* is this a special message that should be retained? */
+{
+    /*
+     * The University of Washington IMAP server (the reference
+     * implementation of IMAP4 written by Mark Crispin) relies
+     * on being able to keep base-UID information in a special
+     * message at the head of the mailbox.  This message should
+     * neither be deleted nor forwarded.
+     */
+    return (num == 1 && !strncasecmp(buf, "X-IMAP:", 7));
+}
+
 const static struct method pop3 =
 {
     "POP3",		/* Post Office Protocol v3 */
@@ -358,6 +371,7 @@ const static struct method pop3 =
     NULL,		/* no way to fetch body alone */
     NULL,		/* no message trailer */
     pop3_delete,	/* how to delete a message */
+    pop3_retain_check,	/* try not to nuke an IMAP4rev header message */
     "QUIT",		/* the POP3 exit command */
 };