allow focus_fallback to query if a client can be focused without changing the focus order on it

openbox/client.c

@@ -2239,10 +2239,30 @@ Client *client_focus_target(Client *self)
     return self;
 }
 
+gboolean client_can_focus(Client *self)
+{
+    /* same code as in client_focus */
+
+    /* choose the correct target */
+    self = client_focus_target(self);
+
+    if (!self->frame->visible)
+        return FALSE;
+
+    if (!((self->can_focus || self->focus_notify) &&
+          (self->desktop == screen_desktop ||
+           self->desktop == DESKTOP_ALL) &&
+          !self->iconic))
+	return FALSE;
+    return TRUE;
+}
+
 gboolean client_focus(Client *self)
 {
     XEvent ev;
 
+    /* same code as in client_can_focus */
+
     /* choose the correct target */
     self = client_focus_target(self);
 

openbox/client.h

@@ -430,6 +430,10 @@ void client_set_state(Client *self, Atom action, long data1, long data2);
    Client passed to it or another Client if appropriate. */
 Client *client_focus_target(Client *self);
 
+/*! Returns what client_focus would return if passed the same client, but
+  without focusing it or modifying the focus order lists. */
+gboolean client_can_focus(Client *self);
+
 /*! Attempt to focus the client window */
 gboolean client_focus(Client *self);
 

openbox/focus.c

@@ -15,6 +15,7 @@
 
 #include <X11/Xlib.h>
 #include <glib.h>
+#include <assert.h>
 
 Client *focus_client = NULL;
 GList **focus_order = NULL; /* these lists are created when screen_startup
@@ -213,10 +214,13 @@ void focus_fallback(FallbackType type)
                 for (sit = old->group->members; sit; sit = sit->next)
                     if (sit->data == it->data)
                         if (sit->data != old && client_normal(sit->data))
-                            if (client_focus(sit->data))
+                            if (client_can_focus(sit->data)) {
+                                gboolean r = client_focus(sit->data);
+                                assert(r);
                                 return;
                             }
         }
+    }
 
     for (it = focus_order[screen_desktop]; it != NULL; it = it->next)
         if (type != Fallback_Unfocusing || it->data != old)