actively delete _NET_WORKAREA on startup

fixes #1038

include/atoms.xmacro

@@ -15,8 +15,8 @@ xmacro(_NET_WM_STRUT_PARTIAL)
 xmacro(_NET_CLIENT_LIST_STACKING)
 xmacro(_NET_CURRENT_DESKTOP)
 xmacro(_NET_ACTIVE_WINDOW)
-xmacro(_NET_WORKAREA)
 xmacro(_NET_STARTUP_ID)
+xmacro(_NET_WORKAREA)
 xmacro(WM_PROTOCOLS)
 xmacro(WM_DELETE_WINDOW)
 xmacro(UTF8_STRING)

include/ewmh.h

@@ -46,4 +46,21 @@ void ewmh_update_client_list_stacking(xcb_window_t *stack, int num_windows);
  */
 void ewmh_setup_hints(void);
 
+/**
+ * i3 currently does not support _NET_WORKAREA, because it does not correspond
+ * to i3’s concept of workspaces. See also:
+ * http://bugs.i3wm.org/539
+ * http://bugs.i3wm.org/301
+ * http://bugs.i3wm.org/1038
+ *
+ * We need to actively delete this property because some display managers (e.g.
+ * LightDM) set it.
+ *
+ * EWMH: Contains a geometry for each desktop. These geometries specify an area
+ * that is completely contained within the viewport. Work area SHOULD be used by
+ * desktop applications to place desktop icons appropriately.
+ *
+ */
+void ewmh_update_workarea(void);
+
 #endif

src/ewmh.c

@@ -50,11 +50,14 @@ void ewmh_update_active_window(xcb_window_t window) {
 }
 
 /*
- * Updates the workarea for each desktop.
+ * i3 currently does not support _NET_WORKAREA, because it does not correspond
- *
+ * to i3’s concept of workspaces. See also:
- * This function is not called at the moment due to:
  * http://bugs.i3wm.org/539
  * http://bugs.i3wm.org/301
+ * http://bugs.i3wm.org/1038
+ *
+ * We need to actively delete this property because some display managers (e.g.
+ * LightDM) set it.
  *
  * EWMH: Contains a geometry for each desktop. These geometries specify an area
  * that is completely contained within the viewport. Work area SHOULD be used by
@@ -62,55 +65,7 @@ void ewmh_update_active_window(xcb_window_t window) {
  *
  */
 void ewmh_update_workarea(void) {
-    int num_workspaces = 0, count = 0;
+    xcb_delete_property(conn, root, A__NET_WORKAREA);
-    Rect last_rect = {0, 0, 0, 0};
-    Con *output;
-
-    TAILQ_FOREACH(output, &(croot->nodes_head), nodes) {
-        Con *ws;
-        TAILQ_FOREACH(ws, &(output_get_content(output)->nodes_head), nodes) {
-            /* Check if we need to initialize last_rect. The case that the
-             * first workspace is all-zero may happen when the user
-             * assigned workspace 2 for his first screen, for example. Thus
-             * we need an initialized last_rect in the very first run of
-             * the following loop. */
-            if (last_rect.width == 0 && last_rect.height == 0 &&
-                    ws->rect.width != 0 && ws->rect.height != 0) {
-                memcpy(&last_rect, &(ws->rect), sizeof(Rect));
-            }
-            num_workspaces++;
-        }
-    }
-
-    DLOG("Got %d workspaces\n", num_workspaces);
-    uint8_t *workarea = smalloc(sizeof(Rect) * num_workspaces);
-    TAILQ_FOREACH(output, &(croot->nodes_head), nodes) {
-        Con *ws;
-        TAILQ_FOREACH(ws, &(output_get_content(output)->nodes_head), nodes) {
-            DLOG("storing %d: %dx%d with %d x %d\n", count, ws->rect.x,
-                 ws->rect.y, ws->rect.width, ws->rect.height);
-            /* If a workspace is not yet initialized and thus its
-             * dimensions are zero, we will instead put the dimensions
-             * of the last workspace in the list. For example firefox
-             * intersects all workspaces and does not cope so well with
-             * an all-zero workspace. */
-            if (ws->rect.width == 0 || ws->rect.height == 0) {
-                DLOG("re-using last_rect (%dx%d, %d, %d)\n",
-                     last_rect.x, last_rect.y, last_rect.width,
-                     last_rect.height);
-                memcpy(workarea + (sizeof(Rect) * count++), &last_rect, sizeof(Rect));
-                continue;
-            }
-            memcpy(workarea + (sizeof(Rect) * count++), &(ws->rect), sizeof(Rect));
-            memcpy(&last_rect, &(ws->rect), sizeof(Rect));
-        }
-    }
-    xcb_change_property(conn, XCB_PROP_MODE_REPLACE, root,
-            A__NET_WORKAREA, XCB_ATOM_CARDINAL, 32,
-            num_workspaces * (sizeof(Rect) / sizeof(uint32_t)),
-            workarea);
-    free(workarea);
-    xcb_flush(conn);
 }
 
 /*
@@ -164,5 +119,5 @@ void ewmh_setup_hints(void) {
     /* I’m not entirely sure if we need to keep _NET_WM_NAME on root. */
     xcb_change_property(conn, XCB_PROP_MODE_REPLACE, root, A__NET_WM_NAME, A_UTF8_STRING, 8, strlen("i3"), "i3");
 
-    xcb_change_property(conn, XCB_PROP_MODE_REPLACE, root, A__NET_SUPPORTED, XCB_ATOM_ATOM, 32, 19, supported_atoms);
+    xcb_change_property(conn, XCB_PROP_MODE_REPLACE, root, A__NET_SUPPORTED, XCB_ATOM_ATOM, 32, 18, supported_atoms);
 }

src/main.c

@@ -729,6 +729,7 @@ int main(int argc, char *argv[]) {
 
     /* Set up i3 specific atoms like I3_SOCKET_PATH and I3_CONFIG_PATH */
     x_set_i3_atoms();
+    ewmh_update_workarea();
 
     struct ev_io *xcb_watcher = scalloc(sizeof(struct ev_io));
     struct ev_io *xkb = scalloc(sizeof(struct ev_io));

testcases/t/209-ewmh-net-workarea.t

@@ -0,0 +1,71 @@
+#!perl
+# vim:ts=4:sw=4:expandtab
+#
+# Please read the following documents before working on tests:
+# • http://build.i3wm.org/docs/testsuite.html
+#   (or docs/testsuite)
+#
+# • http://build.i3wm.org/docs/lib-i3test.html
+#   (alternatively: perldoc ./testcases/lib/i3test.pm)
+#
+# • http://build.i3wm.org/docs/ipc.html
+#   (or docs/ipc)
+#
+# • http://onyxneon.com/books/modern_perl/modern_perl_a4.pdf
+#   (unless you are already familiar with Perl)
+#
+# Verifies the _NET_WORKAREA hint is deleted in case it is already set on the
+# root window.
+# Ticket: #1038
+# Bug still in: 4.5.1-103-g1f8a860
+use i3test i3_autostart => 0;
+use X11::XCB qw(PROP_MODE_REPLACE);
+
+my $atom_cookie = $x->intern_atom(
+    0, # create!
+    length('_NET_WORKAREA'),
+    '_NET_WORKAREA',
+);
+
+my $_net_workarea_id = $x->intern_atom_reply($atom_cookie->{sequence})->{atom};
+
+$x->change_property(
+    PROP_MODE_REPLACE,
+    $x->get_root_window(),
+    $_net_workarea_id,
+    $x->atom(name => 'CARDINAL')->id,
+    32,
+    4,
+    pack('L4', 0, 0, 1024, 768));
+$x->flush;
+
+sub is_net_workarea_set {
+    my $cookie = $x->get_property(
+        0,
+        $x->get_root_window(),
+        $x->atom(name => '_NET_WORKAREA')->id,
+        $x->atom(name => 'CARDINAL')->id,
+        0,
+        4096,
+    );
+    my $reply = $x->get_property_reply($cookie->{sequence});
+    return 0 if $reply->{value_len} == 0;
+    return 0 if $reply->{format} == 0;
+    return 1
+}
+
+ok(is_net_workarea_set(), '_NET_WORKAREA is set before starting i3');
+
+my $config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+fake-outputs 1024x768+0+0
+EOT
+
+my $pid = launch_with_config($config);
+
+ok(!is_net_workarea_set(), '_NET_WORKAREA not set after starting i3');
+
+exit_gracefully($pid);
+
+done_testing;