Add CSD to border modes

This replaces view.using_csd with a new border mode: B_CSD. This also
removes sway_xdg_shell{_v6}_view.deco_mode and
view->has_client_side_decorations as we can now get these from the
border.

You can use `border toggle` to cycle through the modes including CSD, or
use `border csd` to set it directly. The client must support the
xdg-decoration protocol, and the only client I know of that does is the
example in wlroots.

If the client switches from SSD to CSD without us expecting it (via the
server-decoration protocol), we stash the previous border type into
view.saved_border so we can restore it if the client returns to SSD. I
haven't found a way to test this though.

1 files changed, 73 insertions, 0 deletions

diff --git a/sway/xdg_decoration.c b/sway/xdg_decoration.c
new file mode 100644
index 00000000..2e7e4bd0
--- /dev/null
+++ b/sway/xdg_decoration.c
@@ -0,0 +1,73 @@
+#include <stdlib.h>
+#include "sway/desktop/transaction.h"
+#include "sway/server.h"
+#include "sway/tree/arrange.h"
+#include "sway/tree/view.h"
+#include "sway/xdg_decoration.h"
+#include "log.h"
+
+static void xdg_decoration_handle_destroy(struct wl_listener *listener,
+                void *data) {
+        struct sway_xdg_decoration *deco =
+                wl_container_of(listener, deco, destroy);
+        deco->view->xdg_decoration = NULL;
+        wl_list_remove(&deco->destroy.link);
+        wl_list_remove(&deco->surface_commit.link);
+        wl_list_remove(&deco->link);
+        free(deco);
+}
+
+static void xdg_decoration_handle_surface_commit(struct wl_listener *listener,
+                void *data) {
+        struct sway_xdg_decoration *decoration =
+                wl_container_of(listener, decoration, surface_commit);
+
+        bool csd = decoration->wlr_xdg_decoration->current_mode ==
+                WLR_XDG_TOPLEVEL_DECORATION_V1_MODE_CLIENT_SIDE;
+        struct sway_view *view = decoration->view;
+
+        view_set_csd_from_client(view, csd);
+
+        arrange_container(view->container);
+        transaction_commit_dirty();
+}
+
+void handle_xdg_decoration(struct wl_listener *listener, void *data) {
+        struct wlr_xdg_toplevel_decoration_v1 *wlr_deco = data;
+        struct sway_xdg_shell_view *xdg_shell_view = wlr_deco->surface->data;
+        struct wlr_xdg_surface *wlr_xdg_surface =
+                xdg_shell_view->view.wlr_xdg_surface;
+
+        struct sway_xdg_decoration *deco = calloc(1, sizeof(*deco));
+        if (deco == NULL) {
+                return;
+        }
+
+        deco->view = &xdg_shell_view->view;
+        deco->view->xdg_decoration = deco;
+        deco->wlr_xdg_decoration = wlr_deco;
+
+        wl_signal_add(&wlr_deco->events.destroy, &deco->destroy);
+        deco->destroy.notify = xdg_decoration_handle_destroy;
+
+        // Note: We don't listen to the request_mode signal here, effectively
+        // ignoring any modes the client asks to set. The client can still force a
+        // mode upon us, in which case we get upset but live with it.
+
+        deco->surface_commit.notify = xdg_decoration_handle_surface_commit;
+        wl_signal_add(&wlr_xdg_surface->surface->events.commit,
+                &deco->surface_commit);
+
+        wl_list_insert(&server.xdg_decorations, &deco->link);
+}
+
+struct sway_xdg_decoration *xdg_decoration_from_surface(
+                struct wlr_surface *surface) {
+        struct sway_xdg_decoration *deco;
+        wl_list_for_each(deco, &server.xdg_decorations, link) {
+                if (deco->wlr_xdg_decoration->surface->surface == surface) {
+                        return deco;
+                }
+        }
+        return NULL;
+}