Implement support for inhibiting the screensaver on Wayland

We support both the org.freedesktop.ScreenSaver D-Bus API (same as the X11
backend) and the Wayland idle_inhibit_unstable_v1 protocol.

Some Wayland compositors only support one or the other, so we need both to
for broad compatibility.

src/video/wayland/SDL_waylandvideo.c

@@ -50,6 +50,7 @@
 #include "xdg-decoration-unstable-v1-client-protocol.h"
 #include "org-kde-kwin-server-decoration-manager-client-protocol.h"
 #include "keyboard-shortcuts-inhibit-unstable-v1-client-protocol.h"
+#include "idle-inhibit-unstable-v1-client-protocol.h"
 
 #define WAYLANDVID_DRIVER_NAME "wayland"
 
@@ -179,6 +180,7 @@ Wayland_CreateDevice(int devindex)
     device->SetDisplayMode = Wayland_SetDisplayMode;
     device->GetDisplayModes = Wayland_GetDisplayModes;
     device->GetWindowWMInfo = Wayland_GetWindowWMInfo;
+    device->SuspendScreenSaver = Wayland_SuspendScreenSaver;
 
     device->PumpEvents = Wayland_PumpEvents;
 
@@ -397,6 +399,8 @@ display_handle_global(void *data, struct wl_registry *registry, uint32_t id,
         Wayland_display_add_pointer_constraints(d, id);
     } else if (strcmp(interface, "zwp_keyboard_shortcuts_inhibit_manager_v1") == 0) {
         d->key_inhibitor_manager = wl_registry_bind(d->registry, id, &zwp_keyboard_shortcuts_inhibit_manager_v1_interface, 1);
+    } else if (strcmp(interface, "zwp_idle_inhibit_manager_v1") == 0) {
+        d->idle_inhibit_manager = wl_registry_bind(d->registry, id, &zwp_idle_inhibit_manager_v1_interface, 1);
     } else if (strcmp(interface, "wl_data_device_manager") == 0) {
         d->data_device_manager = wl_registry_bind(d->registry, id, &wl_data_device_manager_interface, SDL_min(3, version));
     } else if (strcmp(interface, "zxdg_decoration_manager_v1") == 0) {
@@ -456,6 +460,10 @@ Wayland_VideoInit(_THIS)
 
     WAYLAND_wl_display_flush(data->display);
 
+#if SDL_USE_LIBDBUS
+    SDL_DBus_Init();
+#endif
+
     return 0;
 }
 
@@ -497,6 +505,9 @@ Wayland_VideoQuit(_THIS)
     Wayland_display_destroy_pointer_constraints(data);
     Wayland_display_destroy_relative_pointer_manager(data);
 
+    if (data->idle_inhibit_manager)
+        zwp_idle_inhibit_manager_v1_destroy(data->idle_inhibit_manager);
+
     if (data->key_inhibitor_manager)
         zwp_keyboard_shortcuts_inhibit_manager_v1_destroy(data->key_inhibitor_manager);
 
@@ -535,6 +546,12 @@ Wayland_VideoQuit(_THIS)
     if (data->registry)
         wl_registry_destroy(data->registry);
 
+/* !!! FIXME: other subsystems use D-Bus, so we shouldn't quit it here;
+       have SDL.c do this at a higher level, or add refcounting. */
+#if SDL_USE_LIBDBUS
+    SDL_DBus_Quit();
+#endif
+
     SDL_free(data->classname);
 }
 

src/video/wayland/SDL_waylandvideo.h

@@ -37,6 +37,8 @@
 #include <EGL/egl.h>
 #include "wayland-util.h"
 
+#include "../../core/linux/SDL_dbus.h"
+
 struct xkb_context;
 struct SDL_WaylandInput;
 
@@ -65,6 +67,7 @@ typedef struct {
     struct zxdg_decoration_manager_v1 *decoration_manager;
     struct org_kde_kwin_server_decoration_manager *kwin_server_decoration_manager;
     struct zwp_keyboard_shortcuts_inhibit_manager_v1 *key_inhibitor_manager;
+    struct zwp_idle_inhibit_manager_v1 *idle_inhibit_manager;
 
     EGLDisplay edpy;
     EGLContext context;

src/video/wayland/SDL_waylandwindow.c

@@ -37,6 +37,7 @@
 #include "xdg-shell-unstable-v6-client-protocol.h"
 #include "xdg-decoration-unstable-v1-client-protocol.h"
 #include "org-kde-kwin-server-decoration-manager-client-protocol.h"
+#include "idle-inhibit-unstable-v1-client-protocol.h"
 
 static float get_window_scale_factor(SDL_Window *window) {
       return ((SDL_WindowData*)window->driverdata)->scale_factor;
@@ -838,6 +839,9 @@ int Wayland_CreateWindow(_THIS, SDL_Window *window)
         }
     }
 
+    /* We may need to create an idle inhibitor for this new window */
+    Wayland_SuspendScreenSaver(_this);
+
     return 0;
 }
 
@@ -916,6 +920,44 @@ void Wayland_SetWindowTitle(_THIS, SDL_Window * window)
     WAYLAND_wl_display_flush( ((SDL_VideoData*)_this->driverdata)->display );
 }
 
+void
+Wayland_SuspendScreenSaver(_THIS)
+{
+    SDL_VideoData *data = (SDL_VideoData *)_this->driverdata;
+
+#if SDL_USE_LIBDBUS
+    if (SDL_DBus_ScreensaverInhibit(_this->suspend_screensaver)) {
+        return;
+    }
+#endif
+
+    /* The idle_inhibit_unstable_v1 protocol suspends the screensaver
+       on a per wl_surface basis, but SDL assumes that suspending
+       the screensaver can be done independently of any window.
+       
+       To reconcile these differences, we propagate the idle inhibit
+       state to each window. If there is no window active, we will
+       be able to inhibit idle once the first window is created.
+    */
+    if (data->idle_inhibit_manager) {
+        SDL_Window *window = _this->windows;
+        while (window) {
+            SDL_WindowData *win_data = window->driverdata;
+
+            if (_this->suspend_screensaver && !win_data->idle_inhibitor) {
+                win_data->idle_inhibitor =
+                    zwp_idle_inhibit_manager_v1_create_inhibitor(data->idle_inhibit_manager,
+                                                                 win_data->surface);
+            } else if (!_this->suspend_screensaver && win_data->idle_inhibitor) {
+                zwp_idle_inhibitor_v1_destroy(win_data->idle_inhibitor);
+                win_data->idle_inhibitor = NULL;
+            }
+
+            window = window->next;
+        }
+    }
+}
+
 void Wayland_DestroyWindow(_THIS, SDL_Window *window)
 {
     SDL_VideoData *data = _this->driverdata;
@@ -937,6 +979,10 @@ void Wayland_DestroyWindow(_THIS, SDL_Window *window)
             org_kde_kwin_server_decoration_release(wind->kwin_server_decoration);
         }
 
+        if (wind->idle_inhibitor) {
+            zwp_idle_inhibitor_v1_destroy(wind->idle_inhibitor);
+        }
+
         if (data->shell.xdg) {
             if (wind->shell_surface.xdg.roleobj.toplevel) {
                 xdg_toplevel_destroy(wind->shell_surface.xdg.roleobj.toplevel);

src/video/wayland/SDL_waylandwindow.h

@@ -66,6 +66,7 @@ typedef struct {
     struct zxdg_toplevel_decoration_v1 *server_decoration;
     struct org_kde_kwin_server_decoration *kwin_server_decoration;
     struct zwp_keyboard_shortcuts_inhibitor_v1 *key_inhibitor;
+    struct zwp_idle_inhibitor_v1 *idle_inhibitor;
 
 #ifdef SDL_VIDEO_DRIVER_WAYLAND_QT_TOUCH
     struct qt_extended_surface *extended_surface;
@@ -97,6 +98,7 @@ extern int Wayland_CreateWindow(_THIS, SDL_Window *window);
 extern void Wayland_SetWindowSize(_THIS, SDL_Window * window);
 extern void Wayland_SetWindowTitle(_THIS, SDL_Window * window);
 extern void Wayland_DestroyWindow(_THIS, SDL_Window *window);
+extern void Wayland_SuspendScreenSaver(_THIS);
 
 extern SDL_bool
 Wayland_GetWindowWMInfo(_THIS, SDL_Window * window, SDL_SysWMinfo * info);