Bugfix: Use both parts of WM_CLASS (it contains instance and class) (Thanks fallen)

Actually, WM_CLASS contains two null-terminated strings, so we cannot
use asprintf() to get its value but rather use strdup() to get both
of them. Both values are compared when a client is matched against
a wm_class/title combination (for assignments for example).

include/data.h

@@ -382,8 +382,10 @@ struct Client {
          * in. If set to true, legacy window names are ignored. */
         bool uses_net_wm_name;
 
-        /** Holds the WM_CLASS, useful for matching the client in commands */
+        /** Holds the WM_CLASS (which consists of two strings, the instance
-        char *window_class;
+         * and the class), useful for matching the client in commands */
+        char *window_class_instance;
+        char *window_class_class;
 
         /** Holds the client’s mark, for vim-like jumping */
         char *mark;

src/client.c

@@ -124,7 +124,10 @@ void client_kill(xcb_connection_t *conn, Client *window) {
 bool client_matches_class_name(Client *client, char *to_class, char *to_title,
                                char *to_title_ucs, int to_title_ucs_len) {
         /* Check if the given class is part of the window class */
-        if (client->window_class == NULL || strcasestr(client->window_class, to_class) == NULL)
+        if ((client->window_class_instance == NULL ||
+             strcasestr(client->window_class_instance, to_class) == NULL) &&
+            (client->window_class_class == NULL ||
+             strcasestr(client->window_class_class, to_class) == NULL))
                 return false;
 
         /* If no title was given, we’re done */

src/handlers.c

@@ -539,7 +539,8 @@ int handle_unmap_notify_event(void *data, xcb_connection_t *conn, xcb_unmap_noti
         client->urgent = false;
         workspace_update_urgent_flag(client->workspace);
 
-        FREE(client->window_class);
+        FREE(client->window_class_instance);
+        FREE(client->window_class_class);
         FREE(client->name);
         free(client);
 
@@ -696,28 +697,23 @@ int handle_windowclass_change(void *data, xcb_connection_t *conn, uint8_t state,
         Client *client = table_get(&by_child, window);
         if (client == NULL)
                 return 1;
-        char *new_class;
-        if (asprintf(&new_class, "%.*s", xcb_get_property_value_length(prop), (char*)xcb_get_property_value(prop)) == -1) {
-                perror("Could not get window class");
-                DLOG("Could not get window class\n");
-                return 1;
-        }
 
-        LOG("WM_CLASS changed to %s\n", new_class);
+        /* We cannot use asprintf here since this property contains two
-        char *old_class = client->window_class;
+         * null-terminated strings (for compatibility reasons). Instead, we
-        client->window_class = new_class;
+         * use strdup() on both strings */
-        FREE(old_class);
+        char *new_class = xcb_get_property_value(prop);
 
-        if (!client->initialized)
+        FREE(client->window_class_instance);
-                return 1;
+        FREE(client->window_class_class);
 
-        if (strcmp(new_class, "tools") == 0 || strcmp(new_class, "Dialog") == 0) {
+        client->window_class_instance = strdup(new_class);
-                DLOG("tool/dialog window, should we put it floating?\n");
+        if ((strlen(new_class) + 1) < xcb_get_property_value_length(prop))
-                if (client->floating == FLOATING_AUTO_OFF)
+                client->window_class_class = strdup(new_class + strlen(new_class) + 1);
-                        toggle_floating_mode(conn, client, true);
+        else client->window_class_class = NULL;
-        }
+        LOG("WM_CLASS changed to %s (instance), %s (class)\n",
+            client->window_class_instance, client->window_class_class);
 
-        return 1;
+        return 0;
 }
 
 /*

src/util.c

@@ -448,7 +448,8 @@ Client *get_matching_client(xcb_connection_t *conn, const char *window_classtitl
 
                 Client *client;
                 SLIST_FOREACH(client, &(ws->focus_stack), focus_clients) {
-                        DLOG("Checking client with class=%s, name=%s\n", client->window_class, client->name);
+                        DLOG("Checking client with class=%s / %s, name=%s\n", client->window_class_instance,
+                             client->window_class_class, client->name);
                         if (!client_matches_class_name(client, to_class, to_title, to_title_ucs, to_title_ucs_len))
                                 continue;