Skip floating cons in focus (child|parent) and stop them from being split

Focusing child from a workspace should now skip over the floating con and
go directly to its child. Focusing parent from that grandchild should leave
the workspace focused again.

src/tree.c

@@ -356,6 +356,10 @@ void tree_split(Con *con, orientation_t orientation) {
         con->layout = (orientation == HORIZ) ? L_SPLITH : L_SPLITV;
         return;
     }
+    else if (con->type == CT_FLOATING_CON) {
+        DLOG("Floating containers can't be split.\n");
+        return;
+    }
 
     Con *parent = con->parent;
 
@@ -396,9 +400,15 @@ void tree_split(Con *con, orientation_t orientation) {
  *
  */
 bool level_up(void) {
+    /* Skip over floating containers and go directly to the grandparent
+     * (which should always be a workspace) */
+    if (focused->parent->type == CT_FLOATING_CON) {
+        con_focus(focused->parent->parent);
+        return true;
+    }
+
     /* We can focus up to the workspace, but not any higher in the tree */
     if ((focused->parent->type != CT_CON &&
-         focused->parent->type != CT_FLOATING_CON &&
          focused->parent->type != CT_WORKSPACE) ||
         focused->type == CT_WORKSPACE) {
         ELOG("'focus parent': Focus is already on the workspace, cannot go higher than that.\n");
@@ -416,9 +426,21 @@ bool level_down(void) {
     /* Go down the focus stack of the current node */
     Con *next = TAILQ_FIRST(&(focused->focus_head));
     if (next == TAILQ_END(&(focused->focus_head))) {
-        printf("cannot go down\n");
+        DLOG("cannot go down\n");
         return false;
     }
+    else if (next->type == CT_FLOATING_CON) {
+        /* Floating cons shouldn't be directly focused; try immediately
+         * going to the grandchild of the focused con. */
+        Con *child = TAILQ_FIRST(&(next->focus_head));
+        if (child == TAILQ_END(&(next->focus_head))) {
+            DLOG("cannot go down\n");
+            return false;
+        }
+        else
+            next = TAILQ_FIRST(&(next->focus_head));
+    }
+
     con_focus(next);
     return true;
 }

testcases/t/135-floating-focus.t

@@ -197,4 +197,23 @@ cmd 'focus right';
 
 is($x->input_focus, $second->id, 'focus on second container');
 
+#############################################################################
+# 7: verify that focusing the parent of a window inside a floating con goes
+# up to the grandparent (workspace) and that focusing child from the ws
+# goes back down to the child of the floating con
+#############################################################################
+
+$tmp = fresh_workspace;
+
+my $tiled = open_window;
+my $floating = open_floating_window;
+is($x->input_focus, $floating->id, 'floating window focused');
+
+cmd 'focus parent';
+
+is(get_ws($tmp)->{focused}, 1, 'workspace is focused');
+cmd 'focus child';
+
+is($x->input_focus, $floating->id, 'floating window focused');
+
 done_testing;