gtk-primary-selection: support multiple devices

When a client was creating multiple data devices for the same seat, we were
only creating one resource. This is a protocol error.

Instead, create one offer per data device.

This commit also makes offers inert when their source is destroyed.

Fixes part of swaywm#1041
Supersedes swaywm#1113

include/wlr/types/wlr_primary_selection.h

@@ -36,7 +36,6 @@ struct wlr_primary_selection_source {
 	void (*cancel)(struct wlr_primary_selection_source *source);
 
 	// source status
-	struct wlr_primary_selection_offer *offer;
 	struct wlr_seat_client *seat_client;
 
 	struct {

types/wlr_primary_selection.c

@@ -9,6 +9,8 @@
 #include "gtk-primary-selection-protocol.h"
 #include "util/signal.h"
 
+#define DEVICE_MANAGER_VERSION 1
+
 static const struct gtk_primary_selection_offer_interface offer_impl;
 
 static struct wlr_primary_selection_offer *offer_from_resource(
@@ -21,12 +23,12 @@ static struct wlr_primary_selection_offer *offer_from_resource(
 static void offer_handle_receive(struct wl_client *client,
 		struct wl_resource *resource, const char *mime_type, int32_t fd) {
 	struct wlr_primary_selection_offer *offer = offer_from_resource(resource);
-
-	if (offer->source && offer == offer->source->offer) {
-		offer->source->send(offer->source, mime_type, fd);
-	} else {
+	if (offer == NULL) {
 		close(fd);
+		return;
 	}
+
+	offer->source->send(offer->source, mime_type, fd);
 }
 
 static void offer_handle_destroy(struct wl_client *client,
@@ -39,31 +41,26 @@ static const struct gtk_primary_selection_offer_interface offer_impl = {
 	.destroy = offer_handle_destroy,
 };
 
-static void offer_resource_handle_destroy(struct wl_resource *resource) {
-	struct wlr_primary_selection_offer *offer = offer_from_resource(resource);
-
-	if (!offer->source) {
-		goto out;
+static void offer_destroy(struct wlr_primary_selection_offer *offer) {
+	if (offer == NULL) {
+		return;
 	}
-
+	// Make resource inert
+	wl_resource_set_user_data(offer->resource, NULL);
 	wl_list_remove(&offer->source_destroy.link);
-
-	if (offer->source->offer != offer) {
-		goto out;
-	}
-
-	offer->source->offer = NULL;
-
-out:
 	free(offer);
 }
 
+static void offer_handle_resource_destroy(struct wl_resource *resource) {
+	struct wlr_primary_selection_offer *offer = offer_from_resource(resource);
+	offer_destroy(offer);
+}
+
 static void offer_handle_source_destroy(struct wl_listener *listener,
 		void *data) {
 	struct wlr_primary_selection_offer *offer =
 		wl_container_of(listener, offer, source_destroy);
-
-	offer->source = NULL;
+	offer_destroy(offer);
 }
 
 
@@ -85,48 +82,42 @@ static void client_source_cancel(
 	gtk_primary_selection_source_send_cancelled(source->resource);
 }
 
-static struct wlr_primary_selection_offer *source_send_offer(
-		struct wlr_primary_selection_source *source,
-		struct wlr_seat_client *target) {
-	if (wl_list_empty(&target->primary_selection_devices)) {
-		return NULL;
-	}
-
+static void source_send_offer(struct wlr_primary_selection_source *source,
+		struct wl_resource *device_resource) {
 	struct wlr_primary_selection_offer *offer =
 		calloc(1, sizeof(struct wlr_primary_selection_offer));
 	if (offer == NULL) {
-		return NULL;
+		wl_resource_post_no_memory(device_resource);
+		return;
 	}
 
-	uint32_t version = wl_resource_get_version(
-		wl_resource_from_link(target->primary_selection_devices.next));
-	offer->resource = wl_resource_create(target->client,
+	struct wl_client *client = wl_resource_get_client(device_resource);
+	uint32_t version = wl_resource_get_version(device_resource);
+	offer->resource = wl_resource_create(client,
 		&gtk_primary_selection_offer_interface, version, 0);
 	if (offer->resource == NULL) {
 		free(offer);
-		return NULL;
+		wl_resource_post_no_memory(device_resource);
+		return;
 	}
 	wl_resource_set_implementation(offer->resource, &offer_impl, offer,
-		offer_resource_handle_destroy);
+		offer_handle_resource_destroy);
 
 	offer->source_destroy.notify = offer_handle_source_destroy;
 	wl_signal_add(&source->events.destroy, &offer->source_destroy);
 
-	struct wl_resource *target_resource;
-	wl_resource_for_each(target_resource, &target->primary_selection_devices) {
-		gtk_primary_selection_device_send_data_offer(target_resource,
-			offer->resource);
-	}
+	gtk_primary_selection_device_send_data_offer(device_resource,
+		offer->resource);
 
 	char **p;
 	wl_array_for_each(p, &source->mime_types) {
 		gtk_primary_selection_offer_send_offer(offer->resource, *p);
 	}
 
 	offer->source = source;
-	source->offer = offer;
 
-	return offer;
+	gtk_primary_selection_device_send_selection(device_resource,
+		offer->resource);
 }
 
 static const struct gtk_primary_selection_source_interface source_impl;
@@ -179,20 +170,13 @@ void wlr_seat_client_send_primary_selection(
 		return;
 	}
 
-	if (seat_client->seat->primary_selection_source) {
-		struct wlr_primary_selection_offer *offer = source_send_offer(
-			seat_client->seat->primary_selection_source, seat_client);
-		if (offer == NULL) {
-			return;
-		}
-
-		struct wl_resource *resource;
-		wl_resource_for_each(resource, &seat_client->primary_selection_devices) {
-			gtk_primary_selection_device_send_selection(resource, offer->resource);
-		}
-	} else {
-		struct wl_resource *resource;
-		wl_resource_for_each(resource, &seat_client->primary_selection_devices) {
+	struct wlr_primary_selection_source *source =
+		seat_client->seat->primary_selection_source;
+	struct wl_resource *resource;
+	wl_resource_for_each(resource, &seat_client->primary_selection_devices) {
+		if (source) {
+			source_send_offer(source, resource);
+		} else {
 			gtk_primary_selection_device_send_selection(resource, NULL);
 		}
 	}
@@ -401,8 +385,8 @@ struct wlr_primary_selection_device_manager *
 		return NULL;
 	}
 	manager->global = wl_global_create(display,
-		&gtk_primary_selection_device_manager_interface, 1, manager,
-		primary_selection_device_manager_bind);
+		&gtk_primary_selection_device_manager_interface, DEVICE_MANAGER_VERSION,
+		manager, primary_selection_device_manager_bind);
 	if (manager->global == NULL) {
 		free(manager);
 		return NULL;