Add XEP-0280 support

src/command/command.c

@@ -859,6 +859,15 @@ static struct cmd_t command_defs[] =
           "shared  : Share logs between all instances, accepts 'on' or 'off', defaults to 'on'.",
           NULL } } },
 
+    { "/carbons",
+      cmd_carbons, parse_args, 1, 1, &cons_carbons_setting,
+      { "/carbons on|off", "Message carbons.",
+      { "/carbons on|off",
+        "---------------",
+        "Enable or disable message carbons.",
+        "The message carbons feature ensures that both sides of all conversations are shared with all the user's clients that implement this protocol.",
+        NULL  } } },
+
     { "/reconnect",
         cmd_reconnect, parse_args, 1, 1, &cons_reconnect_setting,
         { "/reconnect seconds", "Set reconnect interval.",

src/command/commands.c

@@ -730,7 +730,7 @@ cmd_help(gchar **args, struct cmd_help_t help)
 
     } else if (strcmp(args[0], "settings") == 0) {
         gchar *filter[] = { "/account", "/autoaway", "/autoping", "/autoconnect", "/beep",
-            "/chlog", "/flash", "/gone", "/grlog", "/history", "/intype",
+            "/carbons", "/chlog", "/flash", "/gone", "/grlog", "/history", "/intype",
             "/log", "/mouse", "/notify", "/outtype", "/prefs", "/priority",
             "/reconnect", "/roster", "/splash", "/states", "/statuses", "/theme",
             "/titlebar", "/vercheck", "/privileges", "/occupants", "/presence", "/wrap" };
@@ -3887,6 +3887,22 @@ cmd_history(gchar **args, struct cmd_help_t help)
     return result;
 }
 
+gboolean
+cmd_carbons(gchar **args, struct cmd_help_t help)
+{
+    gboolean result = _cmd_set_boolean_preference(args[0], help,
+        "Carbons message", PREF_CARBONS);
+
+    // enable carbons
+    if (strcmp(args[0], "on") == 0) {
+        iq_enable_carbons();
+    }
+    else if (strcmp(args[0], "off") == 0){
+        iq_disable_carbons();
+    }
+    return result;
+}
+
 gboolean
 cmd_away(gchar **args, struct cmd_help_t help)
 {

src/command/commands.h

@@ -85,6 +85,7 @@ gboolean cmd_grlog(gchar **args, struct cmd_help_t help);
 gboolean cmd_group(gchar **args, struct cmd_help_t help);
 gboolean cmd_help(gchar **args, struct cmd_help_t help);
 gboolean cmd_history(gchar **args, struct cmd_help_t help);
+gboolean cmd_carbons(gchar **args, struct cmd_help_t help);
 gboolean cmd_info(gchar **args, struct cmd_help_t help);
 gboolean cmd_intype(gchar **args, struct cmd_help_t help);
 gboolean cmd_invite(gchar **args, struct cmd_help_t help);