Feature: improve active window request handling

Allow client requests of type _NET_ACTIVE_WINDOW to switch workspaces if
they indicate they are a pager. Otherwise, set the urgency hint on that
con to indicate that something happened.

This allows task switchers like skippy-xd to work properly.

http://standards.freedesktop.org/wm-spec/latest/ar01s03.html#idm140251368127856

src/handlers.c

@@ -694,7 +694,11 @@ static void handle_client_message(xcb_client_message_event_t *event) {
 
         tree_render();
     } else if (event->type == A__NET_ACTIVE_WINDOW) {
+        if (event->format != 32)
+            return;
+
         DLOG("_NET_ACTIVE_WINDOW: Window 0x%08x should be activated\n", event->window);
+
         Con *con = con_by_window_id(event->window);
         if (con == NULL) {
             DLOG("Could not get window for client message\n");
@@ -702,8 +706,9 @@ static void handle_client_message(xcb_client_message_event_t *event) {
         }
 
         Con *ws = con_get_workspace(con);
-        if (!workspace_is_visible(ws)) {
+
-            DLOG("Workspace not visible, ignoring _NET_ACTIVE_WINDOW\n");
+        if (ws == NULL) {
+            DLOG("Window is not being managed, ignoring _NET_ACTIVE_WINDOW\n");
             return;
         }
 
@@ -712,10 +717,26 @@ static void handle_client_message(xcb_client_message_event_t *event) {
             return;
         }
 
-        if (ws != con_get_workspace(focused))
+        /* data32[0] indicates the source of the request (application or pager) */
+        if (event->data.data32[0] == 2) {
+            /* Always focus the con if it is from a pager, because this is most
+             * likely from some user action */
+            DLOG("This request came from a pager. Focusing con = %p\n", con);
             workspace_show(ws);
-
             con_focus(con);
+        } else {
+            /* If the request is from an application, only focus if the
+             * workspace is visible. Otherwise set the urgency hint. */
+            if (workspace_is_visible(ws)) {
+                DLOG("Request to focus con on a visible workspace. Focusing con = %p\n", con);
+                workspace_show(ws);
+                con_focus(con);
+            } else {
+                DLOG("Request to focus con on a hidden workspace. Setting urgent con = %p\n", con);
+                con_set_urgency(con, true);
+            }
+        }
+
         tree_render();
     } else if (event->type == A_I3_SYNC) {
         xcb_window_t window = event->data.data32[0];

testcases/t/195-net-active-window.t

@@ -21,7 +21,9 @@
 use i3test;
 
 sub send_net_active_window {
-    my ($id) = @_;
+    my ($id, $source) = @_;
+
+    $source = ($source eq 'pager' ? 2 : 0);
 
     my $msg = pack "CCSLLLLLLL",
         X11::XCB::CLIENT_MESSAGE, # response_type
@@ -29,7 +31,7 @@ sub send_net_active_window {
         0, # sequence
         $id, # destination window
         $x->atom(name => '_NET_ACTIVE_WINDOW')->id,
-        0,
+        $source,
         0,
         0,
         0,
@@ -54,7 +56,8 @@ is($x->input_focus, $win1->id, 'window 1 has focus');
 
 ################################################################################
 # Switch to a different workspace and ensure sending the _NET_ACTIVE_WINDOW
-# ClientMessage has no effect anymore.
+# ClientMessage switches to that workspaces only if source indicates it is a
+# pager and otherwise sets the urgent hint.
 ################################################################################
 
 my $ws2 = fresh_workspace;
@@ -62,9 +65,36 @@ my $win3 = open_window;
 
 is($x->input_focus, $win3->id, 'window 3 has focus');
 
+send_net_active_window($win1->id, 'pager');
+
+is($x->input_focus, $win1->id, 'focus switched to window 1 when message source was a pager');
+
+cmd '[id="' . $win3->id . '"] focus';
+
 send_net_active_window($win1->id);
 
-is($x->input_focus, $win3->id, 'window 3 still has focus');
+is($x->input_focus, $win3->id,
+    'focus did not switch to window 1 on a hidden workspace when message source was an application');
+
+ok(get_ws($ws1)->{urgent}, 'urgent hint set on ws 1');
+
+
+################################################################################
+# Make sure the ClientMessage only works with managed windows, and specifying a
+# window that is not managed does not crash i3 (#774)
+################################################################################
+
+my $dock = open_window(window_type => $x->atom(name => '_NET_WM_WINDOW_TYPE_DOCK'));
+
+send_net_active_window($dock->id);
+
+does_i3_live;
+is($x->input_focus, $win3->id, 'dock did not get input focus');
+
+send_net_active_window($x->get_root_window());
+
+does_i3_live;
+is($x->input_focus, $win3->id, 'root window did not get input focus');
 
 ################################################################################
 # Move a window to the scratchpad, send a _NET_ACTIVE_WINDOW for it and verify