linux_dmabuf_v1: allow callbacks for checking dmabuf import

include/wlr/types/wlr_linux_dmabuf_v1.h

@@ -64,6 +64,9 @@ struct wlr_linux_dmabuf_v1 {
 	int main_device_fd; // to sanity check FDs sent by clients, -1 if unavailable
 
 	struct wl_listener display_destroy;
+
+	bool (*check_dmabuf_callback)(struct wlr_dmabuf_attributes *attribs, void *data);
+	void *check_dmabuf_callback_data;
 };
 
 /**
@@ -83,6 +86,15 @@ struct wlr_linux_dmabuf_v1 *wlr_linux_dmabuf_v1_create(struct wl_display *displa
 struct wlr_linux_dmabuf_v1 *wlr_linux_dmabuf_v1_create_with_renderer(struct wl_display *display,
 	uint32_t version, struct wlr_renderer *renderer);
 
+/**
+ * Set the dmabuf import check callback
+ *
+ * This can be used by consumers who want to implement specific dmabuf checks. Useful for
+ * users such as gamescope who do not use the rendering logic of wlroots.
+ */
+void wlr_linux_dmabuf_v1_set_check_dmabuf_callback(struct wlr_linux_dmabuf_v1 *linux_dmabuf,
+	bool (*callback)(struct wlr_dmabuf_attributes *attribs, void *data), void *data);
+
 /**
  * Set a surface's DMA-BUF feedback.
  *

types/wlr_linux_dmabuf_v1.c

@@ -205,8 +205,9 @@ static void buffer_handle_resource_destroy(struct wl_resource *buffer_resource)
 	wlr_buffer_drop(&buffer->base);
 }
 
-static bool check_import_dmabuf(struct wlr_linux_dmabuf_v1 *linux_dmabuf,
-		struct wlr_dmabuf_attributes *attribs) {
+static bool check_import_dmabuf(struct wlr_dmabuf_attributes *attribs, void *data) {
+	struct wlr_linux_dmabuf_v1 *linux_dmabuf = data;
+
 	if (linux_dmabuf->main_device_fd < 0) {
 		return true;
 	}
@@ -344,7 +345,8 @@ static void params_create_common(struct wl_resource *params_resource,
 	}
 
 	/* Check if dmabuf is usable */
-	if (!check_import_dmabuf(linux_dmabuf, &attribs)) {
+	if (!linux_dmabuf->check_dmabuf_callback(&attribs,
+				linux_dmabuf->check_dmabuf_callback_data)) {
 		goto err_failed;
 	}
 
@@ -974,6 +976,9 @@ struct wlr_linux_dmabuf_v1 *wlr_linux_dmabuf_v1_create(struct wl_display *displa
 	linux_dmabuf->display_destroy.notify = handle_display_destroy;
 	wl_display_add_destroy_listener(display, &linux_dmabuf->display_destroy);
 
+	wlr_linux_dmabuf_v1_set_check_dmabuf_callback(linux_dmabuf,
+		check_import_dmabuf, linux_dmabuf);
+
 	wlr_buffer_register_resource_interface(&buffer_resource_interface);
 
 	return linux_dmabuf;
@@ -1000,6 +1005,13 @@ struct wlr_linux_dmabuf_v1 *wlr_linux_dmabuf_v1_create_with_renderer(struct wl_d
 	return linux_dmabuf;
 }
 
+void wlr_linux_dmabuf_v1_set_check_dmabuf_callback(struct wlr_linux_dmabuf_v1 *linux_dmabuf,
+		bool (*callback)(struct wlr_dmabuf_attributes *attribs, void *data), void *data) {
+	assert(callback);
+	linux_dmabuf->check_dmabuf_callback = callback;
+	linux_dmabuf->check_dmabuf_callback_data = data;
+}
+
 bool wlr_linux_dmabuf_v1_set_surface_feedback(
 		struct wlr_linux_dmabuf_v1 *linux_dmabuf,
 		struct wlr_surface *wlr_surface,