primary-selection: add a serial argument

The serial needs to be bumped when X11 clients set the selection, otherwise
some Wayland clients (e.g. GTK) will overwrite it when they gain focus.

include/wlr/types/wlr_data_device.h

@@ -166,8 +166,10 @@ void wlr_data_device_manager_destroy(struct wlr_data_device_manager *manager);
 void wlr_seat_client_send_selection(struct wlr_seat_client *seat_client);
 
 /**
- * Sets the current selection for the seat. This removes the previous one if
- * there was any.
+ * Sets the current selection for the seat. NULL can be provided to clear it.
+ * This removes the previous one if there was any. In case the selection doesn't
+ * come from a client, wl_display_next_serial() can be used to generate a
+ * serial.
  */
 void wlr_seat_set_selection(struct wlr_seat *seat,
 	struct wlr_data_source *source, uint32_t serial);

include/wlr/types/wlr_gtk_primary_selection.h

@@ -36,7 +36,6 @@ struct wlr_gtk_primary_selection_device {
 	struct wl_list resources; // wl_resource_get_link
 
 	struct wl_list offers; // wl_resource_get_link
-	uint32_t selection_serial;
 
 	struct wl_listener seat_destroy;
 	struct wl_listener seat_focus_change;

include/wlr/types/wlr_primary_selection.h

@@ -48,7 +48,13 @@ void wlr_primary_selection_source_send(
 	struct wlr_primary_selection_source *source, const char *mime_type,
 	int fd);
 
+/**
+ * Sets the current primary selection for the seat. NULL can be provided to
+ * clear it. This removes the previous one if there was any. In case the
+ * selection doesn't come from a client, wl_display_next_serial() can be used to
+ * generate a serial.
+ */
 void wlr_seat_set_primary_selection(struct wlr_seat *seat,
-	struct wlr_primary_selection_source *source);
+	struct wlr_primary_selection_source *source, uint32_t serial);
 
 #endif

include/wlr/types/wlr_seat.h

@@ -200,6 +200,7 @@ struct wlr_seat {
 	uint32_t selection_serial;
 
 	struct wlr_primary_selection_source *primary_selection_source;
+	uint32_t primary_selection_serial;
 
 	// `drag` goes away before `drag_source`, when the implicit grab ends
 	struct wlr_drag *drag;

types/seat/wlr_seat.c

@@ -163,7 +163,8 @@ void wlr_seat_destroy(struct wlr_seat *seat) {
 		seat->selection_source = NULL;
 	}
 
-	wlr_seat_set_primary_selection(seat, NULL);
+	wlr_seat_set_primary_selection(seat, NULL,
+		wl_display_next_serial(seat->display));
 
 	struct wlr_seat_client *client, *tmp;
 	wl_list_for_each_safe(client, tmp, &seat->clients, link) {

types/wlr_gtk_primary_selection.c

@@ -208,16 +208,7 @@ static void device_handle_set_selection(struct wl_client *client,
 		source = &client_source->source;
 	}
 
-	// TODO: improve serial validation
-	if (device->seat->primary_selection_source != NULL &&
-			device->selection_serial - serial < UINT32_MAX / 2) {
-		wlr_log(WLR_DEBUG, "Rejecting set_selection request, invalid serial "
-			"(%"PRIu32" <= %"PRIu32")", serial, device->selection_serial);
-		return;
-	}
-	device->selection_serial = serial;
-
-	wlr_seat_set_primary_selection(device->seat, source);
+	wlr_seat_set_primary_selection(device->seat, source, serial);
 }
 
 static void device_handle_destroy(struct wl_client *client,

types/wlr_primary_selection.c

@@ -1,6 +1,7 @@
 #include <assert.h>
 #include <stdlib.h>
 #include <wlr/types/wlr_primary_selection.h>
+#include <wlr/util/log.h>
 #include "util/signal.h"
 
 void wlr_primary_selection_source_init(
@@ -50,7 +51,14 @@ static void seat_handle_primary_selection_source_destroy(
 }
 
 void wlr_seat_set_primary_selection(struct wlr_seat *seat,
-		struct wlr_primary_selection_source *source) {
+		struct wlr_primary_selection_source *source, uint32_t serial) {
+	if (seat->primary_selection_source != NULL &&
+			seat->primary_selection_serial - serial < UINT32_MAX / 2) {
+		wlr_log(WLR_DEBUG, "Rejecting set_selection request, invalid serial "
+			"(%"PRIu32" <= %"PRIu32")", serial, seat->primary_selection_serial);
+		return;
+	}
+
 	if (seat->primary_selection_source != NULL) {
 		wl_list_remove(&seat->primary_selection_source_destroy.link);
 		wlr_primary_selection_source_destroy(seat->primary_selection_source);
@@ -58,6 +66,8 @@ void wlr_seat_set_primary_selection(struct wlr_seat *seat,
 	}
 
 	seat->primary_selection_source = source;
+	seat->primary_selection_serial = serial;
+
 	if (source != NULL) {
 		seat->primary_selection_source_destroy.notify =
 			seat_handle_primary_selection_source_destroy;

xwayland/selection/incoming.c

@@ -370,7 +370,8 @@ static void xwm_selection_get_targets(struct wlr_xwm_selection *selection) {
 		bool ok = source_get_targets(selection, &source->base.mime_types,
 			&source->mime_types_atoms);
 		if (ok) {
-			wlr_seat_set_primary_selection(xwm->seat, &source->base);
+			wlr_seat_set_primary_selection(xwm->seat, &source->base,
+				wl_display_next_serial(xwm->xwayland->wl_display));
 		} else {
 			wlr_primary_selection_source_destroy(&source->base);
 		}
@@ -427,7 +428,8 @@ int xwm_handle_xfixes_selection_notify(struct wlr_xwm *xwm,
 				wlr_seat_set_selection(xwm->seat, NULL,
 					wl_display_next_serial(xwm->xwayland->wl_display));
 			} else if (selection == &xwm->primary_selection) {
-				wlr_seat_set_primary_selection(xwm->seat, NULL);
+				wlr_seat_set_primary_selection(xwm->seat, NULL,
+					wl_display_next_serial(xwm->xwayland->wl_display));
 			} else if (selection == &xwm->dnd_selection) {
 				// TODO: DND
 			} else {

xwayland/selection/selection.c

@@ -231,7 +231,8 @@ void xwm_selection_finish(struct wlr_xwm *xwm) {
 		if (xwm->seat->primary_selection_source &&
 				primary_selection_source_is_xwayland(
 					xwm->seat->primary_selection_source)) {
-			wlr_seat_set_primary_selection(xwm->seat, NULL);
+			wlr_seat_set_primary_selection(xwm->seat, NULL,
+				wl_display_next_serial(xwm->xwayland->wl_display));
 		}
 		wlr_xwayland_set_seat(xwm->xwayland, NULL);
 	}