[Feature] Allow to fold headers on stop characters

src/client/rspamc.c

@@ -1339,9 +1339,9 @@ rspamc_mime_output (FILE *out, ucl_object_t *result, GString *input,
 
 		folded_symbuf = rspamd_header_value_fold ("X-Spam-Symbols",
 				symbuf->str,
-				0, nl_type);
+				0, nl_type, ",");
 		rspamd_printf_gstring (added_headers, "X-Spam-Symbols: %v%s",
-				folded_symbuf, line_end);
+				folded_symbuf, line_end, ",");
 
 		g_string_free (folded_symbuf, TRUE);
 		g_string_free (symbuf, TRUE);

src/libserver/protocol.c

@@ -1127,11 +1127,11 @@ rspamd_protocol_write_ucl (struct rspamd_task *task,
 
 			if (task->flags & RSPAMD_TASK_FLAG_MILTER) {
 				folded_header = rspamd_header_value_fold ("DKIM-Signature",
-						dkim_sig->str, 80, RSPAMD_TASK_NEWLINES_LF);
+						dkim_sig->str, 80, RSPAMD_TASK_NEWLINES_LF, NULL);
 			}
 			else {
 				folded_header = rspamd_header_value_fold ("DKIM-Signature",
-						dkim_sig->str, 80, task->nlines_type);
+						dkim_sig->str, 80, task->nlines_type, NULL);
 			}
 			/*
 			 * According to milter docs, we need to be extra careful

src/libutil/str_util.c

@@ -918,7 +918,8 @@ GString *
 rspamd_header_value_fold (const gchar *name,
 		const gchar *value,
 		guint fold_max,
-		enum rspamd_newlines_type how)
+		enum rspamd_newlines_type how,
+		const gchar *fold_on_chars)
 {
 	GString *res;
 	const guint default_fold_max = 76;
@@ -1019,6 +1020,13 @@ rspamd_header_value_fold (const gchar *name,
 					cur_len ++;
 				}
 			}
+			else if (fold_on_chars && strchr (fold_on_chars, *p) != NULL) {
+				fold_type = fold_after;
+				state = fold_token;
+				next_state = read_token;
+
+				p ++;
+			}
 			else {
 				p ++;
 				cur_len ++;

src/libutil/str_util.h

@@ -242,12 +242,16 @@ gint rspamd_strings_levenshtein_distance (const gchar *s1, gsize s1len,
  * Fold header using rfc822 rules, return new GString from the previous one
  * @param name name of header (used just for folding)
  * @param value value of header
+ * @param fold_max
+ * @param how
+ * @param fold_on_chars
  * @return new GString with the folded value
  */
 GString *rspamd_header_value_fold (const gchar *name,
 		const gchar *value,
 		guint fold_max,
-		enum rspamd_newlines_type how);
+		enum rspamd_newlines_type how,
+		const gchar *fold_on_chars);
 
 /**
  * Search for a substring `srch` in the text `in` using Apostolico-Crochemore algorithm

src/lua/lua_util.c

@@ -135,11 +135,13 @@ LUA_FUNCTION_DEF (util, levenshtein_distance);
 LUA_FUNCTION_DEF (util, parse_addr);
 
 /***
- * @function util.fold_header(name, value)
+ * @function util.fold_header(name, value, [how, [stop_chars]])
  * Fold rfc822 header according to the folding rules
  *
  * @param {string} name name of the header
  * @param {string} value value of the header
+ * @param {string} how "cr" for \r, "lf" for \n and "crlf" for \r\n (default)
+ * @param {string} stop_chars also fold header when the
  * @return {string} Folded value of the header
  */
 LUA_FUNCTION_DEF (util, fold_header);
@@ -1178,7 +1180,7 @@ lua_util_parse_addr (lua_State *L)
 static gint
 lua_util_fold_header (lua_State *L)
 {
-	const gchar *name, *value, *how;
+	const gchar *name, *value, *how, *stop_chars = NULL;
 	GString *folded;
 
 	name = luaL_checkstring (L, 1);
@@ -1187,24 +1189,29 @@ lua_util_fold_header (lua_State *L)
 	if (name && value) {
 
 		if (lua_isstring (L, 3)) {
+
 			how = lua_tostring (L, 3);
 
+			if (lua_isstring (L, 4)) {
+				stop_chars = lua_tostring (L, 4);
+			}
+
 			if (strcmp (how, "cr") == 0) {
 				folded = rspamd_header_value_fold (name, value, 0,
-						RSPAMD_TASK_NEWLINES_CR);
+						RSPAMD_TASK_NEWLINES_CR, stop_chars);
 			}
 			else if (strcmp (how, "lf") == 0) {
 				folded = rspamd_header_value_fold (name, value, 0,
-						RSPAMD_TASK_NEWLINES_LF);
+						RSPAMD_TASK_NEWLINES_LF, stop_chars);
 			}
 			else {
 				folded = rspamd_header_value_fold (name, value, 0,
-						RSPAMD_TASK_NEWLINES_CRLF);
+						RSPAMD_TASK_NEWLINES_CRLF, stop_chars);
 			}
 		}
 		else {
 			folded = rspamd_header_value_fold (name, value, 0,
-					RSPAMD_TASK_NEWLINES_CRLF);
+					RSPAMD_TASK_NEWLINES_CRLF, stop_chars);
 		}
 
 		if (folded) {