From a4f0666659b0b72f35b0efad95f8d39972391c16 Mon Sep 17 00:00:00 2001
From: Philipp Zabel <p.zabel@pengutronix.de>
Date: Wed, 11 Jan 2023 17:03:49 +0100
Subject: [PATCH] libweston, compositor: let weston_compositor_load_backend
 return backend

Let weston_compositor_load_backend() return a backend pointer and remove
the backend pointer from struct weston_compositor.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
---
 compositor/main.c             | 16 +++++-----------
 include/libweston/libweston.h |  3 +--
 libweston/compositor.c        | 18 +++++++++---------
 3 files changed, 15 insertions(+), 22 deletions(-)

diff --git a/compositor/main.c b/compositor/main.c
index dcb657708..1d8d86d3f 100644
--- a/compositor/main.c
+++ b/compositor/main.c
@@ -2971,7 +2971,6 @@ wet_compositor_load_backend(struct weston_compositor *compositor,
 {
 	struct wet_compositor *wet = to_wet_compositor(compositor);
 	struct wet_backend *wb;
-	int ret;
 
 	wb = xzalloc(sizeof *wb);
 
@@ -2983,20 +2982,15 @@ wet_compositor_load_backend(struct weston_compositor *compositor,
 							     &wb->heads_changed_listener);
 	}
 
-	ret = weston_compositor_load_backend(compositor, backend, config_base);
-
-	if (ret == 0) {
-		/*
-		 * At this point compositor->backend should point to the last
-		 * loaded backend.
-		 */
-		wb->backend = compositor->backend;
-		wl_list_insert(wet->backend_list.prev, &wb->compositor_link);
-	} else {
+	wb->backend = weston_compositor_load_backend(compositor, backend,
+						     config_base);
+	if (!wb->backend) {
 		free(wb);
 		return NULL;
 	}
 
+	wl_list_insert(wet->backend_list.prev, &wb->compositor_link);
+
 	return wb;
 }
 
diff --git a/include/libweston/libweston.h b/include/libweston/libweston.h
index cc76eb684..90b6ec913 100644
--- a/include/libweston/libweston.h
+++ b/include/libweston/libweston.h
@@ -1439,7 +1439,6 @@ struct weston_compositor {
 	struct weston_renderer *renderer;
 	const struct pixel_format_info *read_format;
 
-	struct weston_backend *backend;
 	struct wl_list backend_list;
 
 	struct weston_launcher *launcher;
@@ -2331,7 +2330,7 @@ enum weston_renderer_type {
 	WESTON_RENDERER_GL = 3,
 };
 
-int
+struct weston_backend *
 weston_compositor_load_backend(struct weston_compositor *compositor,
 			       enum weston_compositor_backend backend,
 			       struct weston_backend_config *config_base);
diff --git a/libweston/compositor.c b/libweston/compositor.c
index 32d0f35f2..8ae1d3d91 100644
--- a/libweston/compositor.c
+++ b/libweston/compositor.c
@@ -9537,35 +9537,35 @@ static const char * const backend_map[] = {
  * \param config_base A pointer to a backend-specific configuration
  * structure's 'base' member.
  *
- * \return 0 on success, or -1 on error.
+ * \return A new \c weston_backend on success, or NULL on error.
  *
  * \ingroup compositor
  */
-WL_EXPORT int
+WL_EXPORT struct weston_backend *
 weston_compositor_load_backend(struct weston_compositor *compositor,
 			       enum weston_compositor_backend backend,
 			       struct weston_backend_config *config_base)
 {
 	int (*backend_init)(struct weston_compositor *c,
 			    struct weston_backend_config *config_base);
+	struct weston_backend *b;
 
 	if (backend >= ARRAY_LENGTH(backend_map))
-		return -1;
+		return NULL;
 
 	backend_init = weston_load_module(backend_map[backend],
 					  "weston_backend_init",
 					  LIBWESTON_MODULEDIR);
 	if (!backend_init)
-		return -1;
+		return NULL;
 
 	if (backend_init(compositor, config_base) < 0)
-		return -1;
+		return NULL;
 
-	/* Point compositor->backend to the last loaded backend. */
-	compositor->backend = wl_container_of(compositor->backend_list.next,
-					      compositor->backend, link);
+	/* Return the last loaded backend. */
+	b = wl_container_of(compositor->backend_list.next, b, link);
 
-	return 0;
+	return b;
 }
 
 WL_EXPORT int