Add XWayland support

With Cage becoming more popular since its mention on Phoronix and
therefore getting more use-cases than just my own project, add XWayland
support. The refactoring of 2cf40f7 makes this much easier. Note that
this is a no-cost addition for those of us not using XWayland as it is a
compile-time option that needs to be explicitly enabled by adding
`-Dxwayland=true` to your meson command.

cage.c

@@ -8,6 +8,8 @@
 
 #define _POSIX_C_SOURCE 200112L
 
+#include "config.h"
+
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -17,15 +19,24 @@
 #include <wlr/backend.h>
 #include <wlr/render/wlr_renderer.h>
 #include <wlr/types/wlr_compositor.h>
+#if CAGE_HAS_XWAYLAND
+#include <wlr/types/wlr_xcursor_manager.h>
+#endif
 #include <wlr/types/wlr_data_device.h>
 #include <wlr/types/wlr_output_layout.h>
 #include <wlr/types/wlr_xdg_shell.h>
 #include <wlr/util/log.h>
+#if CAGE_HAS_XWAYLAND
+#include <wlr/xwayland.h>
+#endif
 
 #include "output.h"
 #include "seat.h"
 #include "server.h"
 #include "xdg_shell.h"
+#if CAGE_HAS_XWAYLAND
+#include "xwayland.h"
+#endif
 
 static bool
 spawn_primary_client(char *argv[], pid_t *pid_out)
@@ -69,6 +80,9 @@ main(int argc, char *argv[])
 	struct wlr_compositor *compositor = NULL;
 	struct wlr_data_device_manager *data_device_mgr = NULL;
 	struct wlr_xdg_shell *xdg_shell = NULL;
+#if CAGE_HAS_XWAYLAND
+	struct wlr_xwayland *xwayland = NULL;
+#endif
 	int ret = 0;
 
 	if (argc < 2) {
@@ -146,6 +160,31 @@ main(int argc, char *argv[])
 	server.new_xdg_shell_surface.notify = handle_xdg_shell_surface_new;
 	wl_signal_add(&xdg_shell->events.new_surface, &server.new_xdg_shell_surface);
 
+#if CAGE_HAS_XWAYLAND
+	xwayland = wlr_xwayland_create(server.wl_display, compositor, true);
+	server.new_xwayland_surface.notify = handle_xwayland_surface_new;
+	wl_signal_add(&xwayland->events.new_surface, &server.new_xwayland_surface);
+
+	struct wlr_xcursor_manager *xcursor_manager =
+		wlr_xcursor_manager_create(DEFAULT_XCURSOR, XCURSOR_SIZE);
+	if (!xcursor_manager) {
+		wlr_log(WLR_ERROR, "Cannot create XWayland XCursor manager");
+	        ret = 1;
+		goto end;
+	}
+	if (wlr_xcursor_manager_load(xcursor_manager, 1)) {
+		wlr_log(WLR_ERROR, "Cannot load XWayland XCursor theme");
+	}
+	struct wlr_xcursor *xcursor =
+		wlr_xcursor_manager_get_xcursor(xcursor_manager, DEFAULT_XCURSOR, 1);
+	if (xcursor) {
+		struct wlr_xcursor_image *image = xcursor->images[0];
+		wlr_xwayland_set_cursor(xwayland, image->buffer,
+					image->width * 4, image->width, image->height,
+					image->hotspot_x, image->hotspot_y);
+	}
+#endif
+
 	const char *socket = wl_display_add_socket_auto(server.wl_display);
 	if (!socket) {
 		wlr_log_errno(WLR_ERROR, "Unable to open Wayland socket");
@@ -165,6 +204,12 @@ main(int argc, char *argv[])
 			      "Clients may not be able to connect");
 	}
 
+#if CAGE_HAS_XWAYLAND
+	if (xwayland) {
+		wlr_xwayland_set_seat(xwayland, server.seat->seat);
+	}
+#endif
+
 	pid_t pid;
 	if (!spawn_primary_client(argv + 1, &pid)) {
 		ret = 1;
@@ -178,6 +223,10 @@ main(int argc, char *argv[])
 
 end:
 	cg_seat_destroy(server.seat);
+#if CAGE_HAS_XWAYLAND
+	wlr_xwayland_destroy(xwayland);
+	wlr_xcursor_manager_destroy(xcursor_manager);
+#endif
 	wlr_xdg_shell_destroy(xdg_shell);
 	wlr_data_device_manager_destroy(data_device_mgr);
 	wlr_compositor_destroy(compositor);

meson.build

@@ -51,6 +51,9 @@ server_protos = declare_dependency(
   sources: server_protos_headers,
 )
 
+conf_data = configuration_data()
+conf_data.set10('CAGE_HAS_XWAYLAND', get_option('xwayland'))
+
 cage_sources = [
   'cage.c',
   'output.c',
@@ -60,6 +63,9 @@ cage_sources = [
 ]
 
 cage_headers = [
+  configure_file(input: 'config.h.in',
+		 output: 'config.h',
+		 configuration: conf_data),
   'output.h',
   'seat.h',
   'server.h',
@@ -67,6 +73,11 @@ cage_headers = [
   'xdg_shell.h',
 ]
 
+if conf_data.get('CAGE_HAS_XWAYLAND', 0) == 1
+  cage_sources += 'xwayland.c'
+  cage_headers += 'xwayland.h'
+endif
+
 executable(
   meson.project_name(),
   cage_sources + cage_headers,
@@ -78,3 +89,12 @@ executable(
   ],
   install: true,
 )
+
+summary = [
+	'',
+	'Cage @0@'.format(meson.project_version()),
+	'',
+	'    xwayland: @0@'.format(conf_data.get('CAGE_HAS_XWAYLAND', false)),
+	''
+]
+message('\n'.join(summary))

meson_options.txt

@@ -0,0 +1 @@
+option('xwayland', type: 'boolean', value: 'false', description: 'Enable support for X11 applications')

output.c

@@ -8,6 +8,8 @@
 
 #define _POSIX_C_SOURCE 200112L
 
+#include "config.h"
+
 #include <stdlib.h>
 #include <unistd.h>
 #include <wayland-server.h>
@@ -19,6 +21,9 @@
 #include <wlr/types/wlr_surface.h>
 #include <wlr/types/wlr_xdg_shell.h>
 #include <wlr/util/log.h>
+#if CAGE_HAS_XWAYLAND
+#include <wlr/xwayland.h>
+#endif
 
 #include "output.h"
 #include "server.h"
@@ -76,6 +81,11 @@ view_for_each_surface(struct cg_view *view, struct render_data *rdata,
 	case CAGE_XDG_SHELL_VIEW:
 		wlr_xdg_surface_for_each_surface(view->xdg_surface, iterator, rdata);
 		break;
+#ifdef CAGE_HAS_XWAYLAND
+	case CAGE_XWAYLAND_VIEW:
+		wlr_surface_for_each_surface(view->wlr_surface, iterator, rdata);
+		break;
+#endif
 	default:
 		wlr_log(WLR_ERROR, "Unrecognized view type: %d", view->type);
 	}

seat.c

@@ -6,6 +6,8 @@
  * See the LICENSE file accompanying this file.
  */
 
+#include "config.h"
+
 #include <stdlib.h>
 #include <wayland-server.h>
 #include <wlr/backend.h>
@@ -14,15 +16,15 @@
 #include <wlr/types/wlr_surface.h>
 #include <wlr/types/wlr_xcursor_manager.h>
 #include <wlr/util/log.h>
+#if CAGE_HAS_XWAYLAND
+#include <wlr/xwayland.h>
+#endif
 
 #include "output.h"
 #include "seat.h"
 #include "server.h"
 #include "view.h"
 
-#define DEFAULT_XCURSOR "left_ptr"
-#define XCURSOR_SIZE 24
-
 static inline bool
 have_dialogs_open(struct cg_server *server)
 {
@@ -52,6 +54,13 @@ view_at(struct cg_view *view, double lx, double ly,
 						      view_sx, view_sy,
 						      &_sx, &_sy);
 		break;
+#ifdef CAGE_HAS_XWAYLAND
+	case CAGE_XWAYLAND_VIEW:
+		_surface = wlr_surface_surface_at(view->wlr_surface,
+						  view_sx, view_sy,
+						  &_sx, &_sy);
+		break;
+#endif
 	default:
 		wlr_log(WLR_ERROR, "Unrecognized view type: %d", view->type);
 	}
@@ -501,6 +510,13 @@ seat_set_focus(struct cg_seat *seat, struct cg_view *view)
 		return;
 	}
 
+#if CAGE_HAS_XWAYLAND
+	if (view->type == CAGE_XWAYLAND_VIEW &&
+	    !wlr_xwayland_or_surface_wants_focus(view->xwayland_surface)) {
+		return;
+	}
+#endif
+
 	if (prev_view) {
 		view_activate(prev_view, false);
 	}

seat.h

@@ -10,6 +10,9 @@
 #include "server.h"
 #include "view.h"
 
+#define DEFAULT_XCURSOR "left_ptr"
+#define XCURSOR_SIZE 24
+
 struct cg_seat {
 	struct wlr_seat *seat;
 	struct cg_server *server;

server.h

@@ -1,9 +1,14 @@
 #ifndef CG_SERVER_H
 #define CG_SERVER_H
 
+#include "config.h"
+
 #include <wayland-server.h>
 #include <wlr/backend.h>
 #include <wlr/types/wlr_output_layout.h>
+#ifdef CAGE_HAS_XWAYLAND
+#include <wlr/xwayland.h>
+#endif
 
 #include "output.h"
 #include "seat.h"
@@ -20,6 +25,10 @@ struct cg_server {
 	struct wlr_output_layout *output_layout;
 	struct cg_output *output;
 	struct wl_listener new_output;
+
+#if CAGE_HAS_XWAYLAND
+	struct wl_listener new_xwayland_surface;
+#endif
 };
 
 #endif

view.h

@@ -1,6 +1,8 @@
 #ifndef CG_VIEW_H
 #define CG_VIEW_H
 
+#include "config.h"
+
 #include <stdbool.h>
 #include <wayland-server.h>
 #include <wlr/types/wlr_box.h>
@@ -11,6 +13,9 @@
 
 enum cg_view_type {
 	CAGE_XDG_SHELL_VIEW,
+#ifdef CAGE_HAS_XWAYLAND
+	CAGE_XWAYLAND_VIEW,
+#endif
 };
 
 struct cg_view {
@@ -22,6 +27,9 @@ struct cg_view {
 	enum cg_view_type type;
 	union {
 		struct wlr_xdg_surface *xdg_surface;
+#ifdef CAGE_HAS_XWAYLAND
+		struct wlr_xwayland_surface *xwayland_surface;
+#endif
 	};
 
 	struct wl_listener destroy;

xwayland.c

@@ -0,0 +1,86 @@
+/*
+ * Cage: A Wayland kiosk.
+ *
+ * Copyright (C) 2018 Jente Hidskes
+ *
+ * See the LICENSE file accompanying this file.
+ */
+
+#include <stdbool.h>
+#include <wayland-server.h>
+#include <wlr/types/wlr_box.h>
+#include <wlr/xwayland.h>
+
+#include "server.h"
+#include "view.h"
+
+static void
+activate(struct cg_view *view, bool activate)
+{
+	wlr_xwayland_surface_activate(view->xwayland_surface, activate);
+}
+
+static void
+maximize(struct cg_view *view, int output_width, int output_height)
+{
+	wlr_xwayland_surface_configure(view->xwayland_surface, 0, 0, output_width, output_height);
+	wlr_xwayland_surface_set_maximized(view->xwayland_surface, true);
+}
+
+static void
+get_geometry(struct cg_view *view, int *width_out, int *height_out)
+{
+	*width_out = view->xwayland_surface->surface->current.width;
+	*height_out = view->xwayland_surface->surface->current.height;
+}
+
+static bool
+is_primary(struct cg_view *view)
+{
+	struct wlr_xwayland_surface *parent = view->xwayland_surface->parent;
+	return parent == NULL;
+}
+
+static void
+handle_xwayland_surface_unmap(struct wl_listener *listener, void *data)
+{
+	struct cg_view *view = wl_container_of(listener, view, unmap);
+	view_unmap(view);
+}
+
+static void
+handle_xwayland_surface_map(struct wl_listener *listener, void *data)
+{
+	struct cg_view *view = wl_container_of(listener, view, map);
+	view_map(view, view->xwayland_surface->surface);
+}
+
+static void
+handle_xwayland_surface_destroy(struct wl_listener *listener, void *data)
+{
+	struct cg_view *view = wl_container_of(listener, view, destroy);
+	view_destroy(view);
+}
+
+void
+handle_xwayland_surface_new(struct wl_listener *listener, void *data)
+{
+	struct cg_server *server = wl_container_of(listener, server, new_xwayland_surface);
+	struct wlr_xwayland_surface *xwayland_surface = data;
+
+	struct cg_view *view = cg_view_create(server);
+	view->type = CAGE_XWAYLAND_VIEW;
+	view->xwayland_surface = xwayland_surface;
+
+	view->map.notify = handle_xwayland_surface_map;
+	wl_signal_add(&xwayland_surface->events.map, &view->map);
+	view->unmap.notify = handle_xwayland_surface_unmap;
+	wl_signal_add(&xwayland_surface->events.unmap, &view->unmap);
+	view->destroy.notify = handle_xwayland_surface_destroy;
+	wl_signal_add(&xwayland_surface->events.destroy, &view->destroy);
+
+	view->activate = activate;
+	view->maximize = maximize;
+	view->get_geometry = get_geometry;
+	view->is_primary = is_primary;
+}

xwayland.h

@@ -0,0 +1,8 @@
+#ifndef XWAYLAND_H
+#define XWAYLAND_H
+
+#include <wayland-server.h>
+
+void handle_xwayland_surface_new(struct wl_listener *listener, void *data);
+
+#endif