Filter RTL unicode characters out

Gajim sends \u200E and \u200F for RTL.
It is planned that Gajim stops doing this and uses some GTK feature to
get the same result.

However users expressed the whish that we filter out such characters in
incoming messages before displaying them to make Profanity more robust.

I'm still not sure whether I like the solution because it means a lot of
allocating/deallocating upon every new message.

Fix #1220

src/event/server_events.c

@@ -68,6 +68,8 @@
 
 #include "ui/ui.h"
 
+static void _clean_incoming_message(ProfMessage *message);
+
 void
 sv_ev_login_account_success(char *account_name, gboolean secured)
 {
@@ -326,6 +328,7 @@ sv_ev_room_message(ProfMessage *message)
 
     GList *triggers = prefs_message_get_triggers(message->plain);
 
+    _clean_incoming_message(message);
     mucwin_incoming_msg(mucwin, message, mentions, triggers);
 
     g_slist_free(mentions);
@@ -397,6 +400,8 @@ sv_ev_incoming_private_message(ProfMessage *message)
         ProfWin *window = wins_new_private(message->jid->fulljid);
         privatewin = (ProfPrivateWin*)window;
     }
+
+    _clean_incoming_message(message);
     privwin_incoming_msg(privatewin, message);
     chat_log_msg_in(message);
 
@@ -418,6 +423,8 @@ sv_ev_delayed_private_message(ProfMessage *message)
         ProfWin *window = wins_new_private(message->jid->fulljid);
         privatewin = (ProfPrivateWin*)window;
     }
+
+    _clean_incoming_message(message);
     privwin_incoming_msg(privatewin, message);
     chat_log_msg_in(message);
 
@@ -529,6 +536,7 @@ _sv_ev_incoming_pgp(ProfChatWin *chatwin, gboolean new_win, ProfMessage *message
     message->plain = p_gpg_decrypt(message->encrypted);
     if (message->plain) {
         message->enc = PROF_MSG_ENC_PGP;
+        _clean_incoming_message(message);
         chatwin_incoming_msg(chatwin, message, new_win);
         if (logit) {
             chat_log_pgp_msg_in(message);
@@ -543,6 +551,7 @@ _sv_ev_incoming_pgp(ProfChatWin *chatwin, gboolean new_win, ProfMessage *message
         }
         message->enc = PROF_MSG_ENC_PLAIN;
         message->plain = strdup(message->body);
+        _clean_incoming_message(message);
         chatwin_incoming_msg(chatwin, message, new_win);
         chat_log_msg_in(message);
         chatwin->pgp_recv = FALSE;
@@ -564,6 +573,7 @@ _sv_ev_incoming_otr(ProfChatWin *chatwin, gboolean new_win, ProfMessage *message
             message->enc = PROF_MSG_ENC_PLAIN;
         }
 
+        _clean_incoming_message(message);
         chatwin_incoming_msg(chatwin, message, new_win);
 
         chat_log_otr_msg_in(message);
@@ -578,6 +588,7 @@ _sv_ev_incoming_otr(ProfChatWin *chatwin, gboolean new_win, ProfMessage *message
 static void
 _sv_ev_incoming_omemo(ProfChatWin *chatwin, gboolean new_win, ProfMessage *message, gboolean logit)
 {
+    _clean_incoming_message(message);
     chatwin_incoming_msg(chatwin, message, new_win);
     if (logit) {
         chat_log_omemo_msg_in(message);
@@ -592,6 +603,7 @@ _sv_ev_incoming_plain(ProfChatWin *chatwin, gboolean new_win, ProfMessage *messa
     if (message->body) {
         message->enc = PROF_MSG_ENC_PLAIN;
         message->plain = strdup(message->body);
+        _clean_incoming_message(message);
         chatwin_incoming_msg(chatwin, message, new_win);
         if (logit) {
             chat_log_msg_in(message);
@@ -1412,3 +1424,21 @@ sv_ev_bookmark_autojoin(Bookmark *bookmark)
 
     free(nick);
 }
+
+static void
+_clean_incoming_message(ProfMessage *message)
+{
+    if (strstr(message->plain, "\u200E")) {
+        char **split = g_strsplit(message->plain, "\u200E", -1);
+        free(message->plain);
+        message->plain = g_strjoinv("", split);
+        g_strfreev(split);
+    }
+
+    if (strstr(message->plain, "\u200F")) {
+        char **split = g_strsplit(message->plain, "\u200F", -1);
+        free(message->plain);
+        message->plain = g_strjoinv("", split);
+        g_strfreev(split);
+    }
+}