Fetch GMail IMAP extensions and stick them in tags, from David Lazar.

child-fetch.c

@@ -517,6 +517,7 @@ fetch_enqueue(struct account *a, struct io *pio, struct mail *m)
 	int			 error;
 	struct tm		*tm;
 	time_t			 t;
+	const char		*tptr;
 
 	/*
 	 * Check for oversize mails. This must be first since there is no
@@ -622,6 +623,17 @@ fetch_enqueue(struct account *a, struct io *pio, struct mail *m)
 			log_debug3("%s: couldn't add received header", a->name);
 	}
 
+	/* Insert Gmail-specific headers. */
+	if ((tptr = find_tag(m->tags, "gmail_msgid")) != NULL &&
+	    insert_header(m, "message-id", "X-GM-MSGID: %s", tptr) != 0)
+		log_warnx("%s: failed to add header X-GM-MSGID", a->name);
+	if ((tptr = find_tag(m->tags, "gmail_thrid")) != NULL &&
+	    insert_header(m, "message-id", "X-GM-THRID: %s", tptr) != 0)
+		log_warnx("%s: failed to add header X-GM-THRID", a->name);
+	if ((tptr = find_tag(m->tags, "gmail_labels")) != NULL &&
+	    insert_header(m, "message-id", "X-GM-LABELS: %s", tptr) != 0)
+		log_warnx("%s: failed to add header X-GM-LABELS", a->name);
+
 	/* Fill wrapped line list. */
 	n = fill_wrapped(m);
 	log_debug2("%s: found %u wrapped lines", a->name, n);

fetch.h

@@ -251,6 +251,7 @@ struct fetch_imap_mail {
 #define IMAP_CAPA_XYZZY 0x2
 #define IMAP_CAPA_STARTTLS 0x4
 #define IMAP_CAPA_NOSPACE 0x8
+#define IMAP_CAPA_GMEXT 0x10
 
 /* fetch-maildir.c */
 extern struct fetch	 fetch_maildir;

imap-common.c

@@ -59,6 +59,9 @@ int	imap_state_next(struct account *, struct fetch_ctx *);
 int	imap_state_body(struct account *, struct fetch_ctx *);
 int	imap_state_line(struct account *, struct fetch_ctx *);
 int	imap_state_mail(struct account *, struct fetch_ctx *);
+int	imap_state_gmext_start(struct account *, struct fetch_ctx *);
+int	imap_state_gmext_body(struct account *, struct fetch_ctx *);
+int	imap_state_gmext_done(struct account *, struct fetch_ctx *);
 int	imap_state_commit(struct account *, struct fetch_ctx *);
 int	imap_state_expunge(struct account *, struct fetch_ctx *);
 int	imap_state_close(struct account *, struct fetch_ctx *);
@@ -402,6 +405,10 @@ imap_state_capability1(struct account *a, struct fetch_ctx *fctx)
 	if (strstr(line, "XYZZY") != NULL)
 		data->capa |= IMAP_CAPA_XYZZY;
 
+	/* GMail IMAP extensions. */
+	if (strstr(line, "X-GM-EXT-1") != NULL)
+		data->capa |= IMAP_CAPA_GMEXT;
+
 	if (strstr(line, "STARTTLS") != NULL)
 		data->capa |= IMAP_CAPA_STARTTLS;
 
@@ -952,6 +959,81 @@ imap_state_line(struct account *a, struct fetch_ctx *fctx)
 /* Mail state. */
 int
 imap_state_mail(struct account *a, struct fetch_ctx *fctx)
+{
+	struct fetch_imap_data	*data = a->data;
+	char	*line;
+
+	if (imap_getln(a, fctx, IMAP_TAGGED, &line) != 0)
+		return (FETCH_ERROR);
+	if (line == NULL)
+		return (FETCH_BLOCK);
+	if (!imap_okay(line))
+		return (imap_bad(a, line));
+
+	if (data->capa & IMAP_CAPA_GMEXT) {
+		fctx->state = imap_state_gmext_start;
+		return (FETCH_AGAIN);
+	}
+
+	fctx->state = imap_state_next;
+	return (FETCH_MAIL);
+}
+
+/* GMail extensions start state. */
+int
+imap_state_gmext_start(struct account *a, struct fetch_ctx *fctx)
+{
+	struct fetch_imap_data	*data = a->data;
+	struct mail				*m = fctx->mail;
+	struct fetch_imap_mail	*aux = m->auxdata;
+
+	if (imap_putln(a, "%u FETCH %u (X-GM-MSGID X-GM-THRID X-GM-LABELS)",
+		++data->tag, aux->uid) != 0)
+		return (FETCH_ERROR);
+
+	fctx->state = imap_state_gmext_body;
+	return (FETCH_AGAIN);
+}
+
+/* GMail extensions body state. */
+int
+imap_state_gmext_body(struct account *a, struct fetch_ctx *fctx)
+{
+	struct mail	*m = fctx->mail;
+	char		*line, *lb;
+	u_int		 n;
+	uint64_t	 thrid, msgid;
+	size_t		 lblen;
+
+	if (imap_getln(a, fctx, IMAP_UNTAGGED, &line) != 0)
+		return (FETCH_ERROR);
+	if (line == NULL)
+		return (FETCH_BLOCK);
+
+	if (sscanf(line, "* %u FETCH (X-GM-THRID %llu X-GM-MSGID %llu ", &n,
+	    &thrid, &msgid) != 3)
+		return (imap_invalid(a, line));
+	if ((lb = strstr(line, "X-GM-LABELS")) == NULL)
+		return (imap_invalid(a, line));
+	if ((lb = strchr(lb, '(')) == NULL)
+		return (imap_invalid(a, line));
+	lb++; /* drop '(' */
+	lblen = strlen(lb);
+	if (lblen < 2 || lb[lblen - 1] != ')' || lb[lblen - 2] != ')')
+		return (imap_invalid(a, line));
+	lblen -= 2; /* drop '))' from the end */
+
+	add_tag(&m->tags, "gmail_msgid", "%llu", msgid);
+	add_tag(&m->tags, "gmail_thrid", "%llu", thrid);
+	add_tag(&m->tags, "gmail_labels", "%.*s", (int)lblen, lb);
+
+	fctx->state = imap_state_gmext_done;
+	return (FETCH_AGAIN);
+}
+
+/* GMail extensions done state. */
+int
+imap_state_gmext_done(struct account *a, struct fetch_ctx *fctx)
 {
 	char	*line;