data-device: remove wlr_data_source.seat_client

Since the source doesn't always come from a client, this field
doesn't make sense. It is replaced by a new "finalized" field in
wlr_client_data_source. This is used to make sure set_actions is
not sent after start_drag has been sent.

A check in data_offer_choose_action has been removed: if an offer
has been sent then start_drag has been called, no need to check.

I also wanted to add a check for wl_data_source.offer, but it
turns out (1) this isn't in the spec (2) it breaks GTK+.

This is some preliminary work for Firefox on Wayland compatibility.

include/types/wlr_data_device.h

@@ -11,6 +11,7 @@ struct wlr_client_data_source {
 	struct wlr_data_source source;
 	struct wlr_data_source_impl impl;
 	struct wl_resource *resource;
+	bool finalized;
 };
 
 extern const struct wlr_surface_role drag_icon_surface_role;

include/wlr/types/wlr_data_device.h

@@ -73,7 +73,6 @@ struct wlr_data_source {
 	// source status
 	bool accepted;
 	struct wlr_data_offer *offer;
-	struct wlr_seat_client *seat_client;
 
 	// drag'n'drop status
 	enum wl_data_device_manager_dnd_action current_dnd_action;

types/data_device/wlr_data_device.c

@@ -25,16 +25,21 @@ static struct wlr_seat_client *seat_client_from_data_device_resource(
 static void data_device_set_selection(struct wl_client *client,
 		struct wl_resource *device_resource,
 		struct wl_resource *source_resource, uint32_t serial) {
+	struct wlr_seat_client *seat_client =
+		seat_client_from_data_device_resource(device_resource);
+
 	struct wlr_client_data_source *source = NULL;
 	if (source_resource != NULL) {
 		source = client_data_source_from_resource(source_resource);
 	}
 
-	struct wlr_seat_client *seat_client =
-		seat_client_from_data_device_resource(device_resource);
-
-	struct wlr_data_source *wlr_source = (struct wlr_data_source *)source;
+	struct wlr_data_source *wlr_source =
+		source != NULL ? &source->source : NULL;
 	wlr_seat_set_selection(seat_client->seat, wlr_source, serial);
+
+	if (source != NULL) {
+		source->finalized = true;
+	}
 }
 
 static void data_device_start_drag(struct wl_client *client,
@@ -45,15 +50,13 @@ static void data_device_start_drag(struct wl_client *client,
 	struct wlr_seat_client *seat_client =
 		seat_client_from_data_device_resource(device_resource);
 	struct wlr_surface *origin = wlr_surface_from_resource(origin_resource);
-	struct wlr_data_source *source = NULL;
-	struct wlr_surface *icon = NULL;
 
-	if (source_resource) {
-		struct wlr_client_data_source *client_source =
-			client_data_source_from_resource(source_resource);
-		source = (struct wlr_data_source *)client_source;
+	struct wlr_client_data_source *source = NULL;
+	if (source_resource != NULL) {
+		source = client_data_source_from_resource(source_resource);
 	}
 
+	struct wlr_surface *icon = NULL;
 	if (icon_resource) {
 		icon = wlr_surface_from_resource(icon_resource);
 		if (!wlr_surface_set_role(icon, &drag_icon_surface_role, NULL,
@@ -62,13 +65,16 @@ static void data_device_start_drag(struct wl_client *client,
 		}
 	}
 
-	if (!seat_client_start_drag(seat_client, source, icon, origin, serial)) {
+	struct wlr_data_source *wlr_source =
+		source != NULL ? &source->source : NULL;
+	if (!seat_client_start_drag(seat_client, wlr_source, icon,
+			origin, serial)) {
 		wl_resource_post_no_memory(device_resource);
 		return;
 	}
 
-	if (source) {
-		source->seat_client = seat_client;
+	if (source != NULL) {
+		source->finalized = true;
 	}
 }
 

types/data_device/wlr_data_offer.c

@@ -41,8 +41,7 @@ static uint32_t data_offer_choose_action(struct wlr_data_offer *offer) {
 		return WL_DATA_DEVICE_MANAGER_DND_ACTION_NONE;
 	}
 
-	if (offer->source->seat_client &&
-			offer->source->compositor_action & available_actions) {
+	if (offer->source->compositor_action & available_actions) {
 		return offer->source->compositor_action;
 	}
 

types/data_device/wlr_data_source.c

@@ -207,11 +207,10 @@ static void data_source_set_actions(struct wl_client *client,
 		return;
 	}
 
-	if (source->source.seat_client) {
+	if (source->finalized) {
 		wl_resource_post_error(source->resource,
 			WL_DATA_SOURCE_ERROR_INVALID_ACTION_MASK,
-			"invalid action change after "
-			"wl_data_device.start_drag");
+			"invalid action change after wl_data_device.start_drag");
 		return;
 	}