xwayland-shell-v1: new protocol implementation

References: https://gitlab.freedesktop.org/wayland/wayland-protocols/-/merge_requests/163

include/wlr/xwayland/shell.h

@@ -0,0 +1,57 @@
+/*
+ * This an unstable interface of wlroots. No guarantees are made regarding the
+ * future consistency of this API.
+ */
+#ifndef WLR_USE_UNSTABLE
+#error "Add -DWLR_USE_UNSTABLE to enable unstable wlroots features"
+#endif
+
+#ifndef WLR_XWAYLAND_SHELL_H
+#define WLR_XWAYLAND_SHELL_H
+
+#include <stdbool.h>
+#include <wayland-server-core.h>
+
+/**
+ * The Xwayland shell.
+ *
+ * This is a shell only exposed to Xwayland.
+ */
+struct wlr_xwayland_shell_v1 {
+	struct wl_global *global;
+
+	struct {
+		struct wl_signal new_surface; // struct wlr_xwayland_surface_v1
+	} events;
+
+	// private state
+
+	struct wl_listener display_destroy;
+};
+
+/**
+ * An Xwayland shell surface.
+ */
+struct wlr_xwayland_surface_v1 {
+	struct wlr_surface *surface;
+	uint64_t serial;
+
+	// private state
+
+	struct wl_resource *resource;
+	struct wlr_xwayland_shell_v1 *shell;
+	bool added;
+
+	struct wl_listener surface_destroy;
+};
+
+/**
+ * Create the xwayland_shell_v1 global.
+ *
+ * Compositors should add a global filter (see wl_display_set_global_filter())
+ * to only expose this global to Xwayland clients.
+ */
+struct wlr_xwayland_shell_v1 *wlr_xwayland_shell_v1_create(
+	struct wl_display *display, uint32_t version);
+
+#endif

protocol/meson.build

@@ -24,6 +24,7 @@ protocols = {
 	'ext-session-lock-v1': wl_protocol_dir / 'staging/ext-session-lock/ext-session-lock-v1.xml',
 	'single-pixel-buffer-v1': wl_protocol_dir / 'staging/single-pixel-buffer/single-pixel-buffer-v1.xml',
 	'xdg-activation-v1': wl_protocol_dir / 'staging/xdg-activation/xdg-activation-v1.xml',
+	'xwayland-shell-v1': wl_protocol_dir / 'staging/xwayland-shell/xwayland-shell-v1.xml',
 
 	# Unstable upstream protocols
 	'fullscreen-shell-unstable-v1': wl_protocol_dir / 'unstable/fullscreen-shell/fullscreen-shell-unstable-v1.xml',

xwayland/meson.build

@@ -68,6 +68,7 @@ wlr_files += files(
 	'selection/outgoing.c',
 	'selection/selection.c',
 	'server.c',
+	'shell.c',
 	'sockets.c',
 	'xwayland.c',
 	'xwm.c',

xwayland/shell.c

@@ -0,0 +1,185 @@
+#include <assert.h>
+#include <stdlib.h>
+#include <wlr/types/wlr_compositor.h>
+#include <wlr/xwayland/shell.h>
+
+#include "xwayland-shell-v1-protocol.h"
+
+#define SHELL_VERSION 1
+
+static void destroy_resource(struct wl_client *client,
+		struct wl_resource *resource) {
+	wl_resource_destroy(resource);
+}
+
+static const struct xwayland_shell_v1_interface shell_impl;
+static const struct xwayland_surface_v1_interface xwl_surface_impl;
+
+/**
+ * Get a struct wlr_xwayland_shell_v1 from a resource.
+ */
+static struct wlr_xwayland_shell_v1 *shell_from_resource(
+		struct wl_resource *resource) {
+	assert(wl_resource_instance_of(resource,
+		&xwayland_shell_v1_interface, &shell_impl));
+	return wl_resource_get_user_data(resource);
+}
+
+/**
+ * Get a struct wlr_xwayland_surface_v1 from a resource.
+ *
+ * Returns NULL if the Xwayland surface is inert.
+ */
+static struct wlr_xwayland_surface_v1 *xwl_surface_from_resource(
+		struct wl_resource *resource) {
+	assert(wl_resource_instance_of(resource,
+		&xwayland_surface_v1_interface, &xwl_surface_impl));
+	return wl_resource_get_user_data(resource);
+}
+
+static void xwl_surface_role_commit(struct wlr_surface *surface) {
+	struct wlr_xwayland_surface_v1 *xwl_surface = surface->role_data;
+
+	if (xwl_surface->serial != 0 && !xwl_surface->added) {
+		xwl_surface->added = true;
+		wl_signal_emit_mutable(&xwl_surface->shell->events.new_surface,
+			xwl_surface);
+	}
+}
+
+static void xwl_surface_role_destroy(struct wlr_surface *surface) {
+	struct wlr_xwayland_surface_v1 *xwl_surface = surface->role_data;
+	wl_list_remove(&xwl_surface->surface_destroy.link);
+	wl_resource_set_user_data(xwl_surface->resource, NULL); // make inert
+	free(xwl_surface);
+}
+
+static const struct wlr_surface_role xwl_surface_role = {
+	.name = "xwayland_surface_v1",
+	.commit = xwl_surface_role_commit,
+	.destroy = xwl_surface_role_destroy,
+};
+
+static void xwl_surface_handle_set_serial(struct wl_client *client,
+		struct wl_resource *resource, uint32_t serial_lo, uint32_t serial_hi) {
+	struct wlr_xwayland_surface_v1 *xwl_surface =
+		xwl_surface_from_resource(resource);
+	if (xwl_surface == NULL) {
+		return;
+	}
+
+	if (xwl_surface->serial != 0) {
+		wl_resource_post_error(resource,
+			XWAYLAND_SURFACE_V1_ERROR_ALREADY_ASSOCIATED,
+			"xwayland_surface_v1 is already associated with another X11 serial");
+		return;
+	}
+
+	xwl_surface->serial = ((uint64_t)serial_hi << 32) | serial_lo;
+}
+
+static const struct xwayland_surface_v1_interface xwl_surface_impl = {
+	.destroy = destroy_resource,
+	.set_serial = xwl_surface_handle_set_serial,
+};
+
+static void xwl_surface_handle_surface_destroy(struct wl_listener *listener,
+		void *data) {
+	struct wlr_xwayland_surface_v1 *xwl_surface =
+		wl_container_of(listener, xwl_surface, surface_destroy);
+	wlr_surface_destroy_role_object(xwl_surface->surface);
+}
+
+static void xwl_surface_handle_resource_destroy(struct wl_resource *resource) {
+	struct wlr_xwayland_surface_v1 *xwl_surface =
+		xwl_surface_from_resource(resource);
+	if (xwl_surface != NULL) {
+		wlr_surface_destroy_role_object(xwl_surface->surface);
+	}
+}
+
+static void shell_handle_get_xwayland_surface(struct wl_client *client,
+		struct wl_resource *shell_resource, uint32_t id,
+		struct wl_resource *surface_resource) {
+	struct wlr_xwayland_shell_v1 *shell = shell_from_resource(shell_resource);
+	struct wlr_surface *surface = wlr_surface_from_resource(surface_resource);
+
+	struct wlr_xwayland_surface_v1 *xwl_surface = calloc(1, sizeof(*xwl_surface));
+	if (xwl_surface == NULL) {
+		wl_client_post_no_memory(client);
+		return;
+	}
+
+	if (!wlr_surface_set_role(surface, &xwl_surface_role, xwl_surface,
+			shell_resource, XWAYLAND_SHELL_V1_ERROR_ROLE)) {
+		free(xwl_surface);
+		return;
+	}
+
+	xwl_surface->surface = surface;
+	xwl_surface->shell = shell;
+
+	uint32_t version = wl_resource_get_version(shell_resource);
+	xwl_surface->resource = wl_resource_create(client,
+		&xwayland_surface_v1_interface, version, id);
+	if (xwl_surface->resource == NULL) {
+		free(xwl_surface);
+		wl_client_post_no_memory(client);
+		return;
+	}
+	wl_resource_set_implementation(xwl_surface->resource, &xwl_surface_impl,
+		xwl_surface, xwl_surface_handle_resource_destroy);
+
+	xwl_surface->surface_destroy.notify = xwl_surface_handle_surface_destroy;
+	wl_signal_add(&surface->events.destroy, &xwl_surface->surface_destroy);
+}
+
+static const struct xwayland_shell_v1_interface shell_impl = {
+	.destroy = destroy_resource,
+	.get_xwayland_surface = shell_handle_get_xwayland_surface,
+};
+
+static void shell_bind(struct wl_client *client, void *data, uint32_t version,
+		uint32_t id) {
+	struct wlr_xwayland_shell_v1 *shell = data;
+
+	struct wl_resource *resource = wl_resource_create(client,
+		&xwayland_shell_v1_interface, version, id);
+	if (resource == NULL) {
+		wl_client_post_no_memory(client);
+		return;
+	}
+	wl_resource_set_implementation(resource, &shell_impl, shell, NULL);
+}
+
+static void handle_display_destroy(struct wl_listener *listener, void *data) {
+	struct wlr_xwayland_shell_v1 *shell =
+		wl_container_of(listener, shell, display_destroy);
+	wl_list_remove(&shell->display_destroy.link);
+	wl_global_destroy(shell->global);
+	free(shell);
+}
+
+struct wlr_xwayland_shell_v1 *wlr_xwayland_shell_v1_create(
+		struct wl_display *display, uint32_t version) {
+	assert(version <= SHELL_VERSION);
+
+	struct wlr_xwayland_shell_v1 *shell = calloc(1, sizeof(*shell));
+	if (shell == NULL) {
+		return NULL;
+	}
+
+	shell->global = wl_global_create(display, &xwayland_shell_v1_interface,
+		version, shell, shell_bind);
+	if (shell->global == NULL) {
+		free(shell);
+		return NULL;
+	}
+
+	wl_signal_init(&shell->events.new_surface);
+
+	shell->display_destroy.notify = handle_display_destroy;
+	wl_display_add_destroy_listener(display, &shell->display_destroy);
+
+	return shell;
+}