platform: refactor NMPObject cast macros using _Generic()th/dedup-multi-bgo784220

This way, we also accept void pointers, while preserving constness.

6 files changed, 65 insertions, 43 deletions

diff --git a/shared/nm-utils/nm-macros-internal.h b/shared/nm-utils/nm-macros-internal.h
index 12794c3473..66b4aa8d60 100644
--- a/shared/nm-utils/nm-macros-internal.h
+++ b/shared/nm-utils/nm-macros-internal.h
@@ -242,6 +242,35 @@ NM_G_ERROR_MSG (GError *error)
 
 /*****************************************************************************/
 
+#if (defined (__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 9 ))) || (defined (__clang__))
+#define _NM_CC_SUPPORT_GENERIC 1
+#else
+#define _NM_CC_SUPPORT_GENERIC 0
+#endif
+
+#if _NM_CC_SUPPORT_GENERIC
+#define _NM_CONSTCAST(type, obj) \
+	(_Generic ((obj), \
+	           void *           : ((type *) (obj)), \
+	           void *const      : ((type *) (obj)), \
+	           const void *     : ((const type *) (obj)), \
+	           const void *const: ((const type *) (obj)), \
+	           const type *     : (obj), \
+	           const type *const: (obj), \
+	           type *           : (obj), \
+	           type *const      : (obj)))
+#else
+/* _NM_CONSTCAST() is there to preserve constness of a pointer.
+ * It uses C11's _Generic(). If that is not supported, we fall back
+ * to casting away constness. So, with _Generic, we get some additional
+ * static type checking by preserving constness, without, we cast it
+ * to a non-const pointer. */
+#define _NM_CONSTCAST(type, obj) \
+	((type *) (obj))
+#endif
+
+/*****************************************************************************/
+
 #define _NM_IN_SET_EVAL_1( op, _x, y)           (_x == (y))
 #define _NM_IN_SET_EVAL_2( op, _x, y, ...)      (_x == (y)) op _NM_IN_SET_EVAL_1  (op, _x, __VA_ARGS__)
 #define _NM_IN_SET_EVAL_3( op, _x, y, ...)      (_x == (y)) op _NM_IN_SET_EVAL_2  (op, _x, __VA_ARGS__)
@@ -537,7 +566,7 @@ _notify (obj_type *obj, _PropertyEnums prop) \
 /* these are implemented as a macro, because they accept self
  * as both (type*) and (const type*), and return a const
  * private pointer accordingly. */
-#define __NM_GET_PRIVATE(self, type, is_check, result_cmd) \
+#define __NM_GET_PRIVATE(self, type, is_check, addrop) \
 	({ \
 		/* preserve the const-ness of self. Unfortunately, that
 		 * way, @self cannot be a void pointer */ \
@@ -547,11 +576,11 @@ _notify (obj_type *obj, _PropertyEnums prop) \
 		_nm_unused const type *const _self2 = (_self); \
 		\
 		nm_assert (is_check (_self)); \
-		( result_cmd ); \
+		( addrop ( _NM_CONSTCAST (type, _self)->_priv) ); \
 	})
 
-#define _NM_GET_PRIVATE(self, type, is_check)     __NM_GET_PRIVATE(self, type, is_check, &_self->_priv)
-#define _NM_GET_PRIVATE_PTR(self, type, is_check) __NM_GET_PRIVATE(self, type, is_check,  _self->_priv)
+#define _NM_GET_PRIVATE(self, type, is_check)     __NM_GET_PRIVATE(self, type, is_check, &)
+#define _NM_GET_PRIVATE_PTR(self, type, is_check) __NM_GET_PRIVATE(self, type, is_check,  )
 
 #define __NM_GET_PRIVATE_VOID(self, type, is_check, result_cmd) \
 	({ \
diff --git a/src/nm-default-route-manager.c b/src/nm-default-route-manager.c
index f0dc75cfd1..f6362bccf6 100644
--- a/src/nm-default-route-manager.c
+++ b/src/nm-default-route-manager.c
@@ -209,7 +209,7 @@ _vt_routes_has_entry (const VTableIP *vtable, const GPtrArray *routes, const Ent
 
 	if (vtable->vt->is_ip4) {
 		for (i = 0; i < routes->len; i++) {
-			const NMPlatformIP4Route *r = NMP_OBJECT_CAST_IP4_ROUTE ((NMPObject *) routes->pdata[i]);
+			const NMPlatformIP4Route *r = NMP_OBJECT_CAST_IP4_ROUTE (routes->pdata[i]);
 
 			route.rx.rt_source = r->rt_source;
 			if (nm_platform_ip4_route_cmp (r, &route.r4) == 0)
@@ -217,7 +217,7 @@ _vt_routes_has_entry (const VTableIP *vtable, const GPtrArray *routes, const Ent
 		}
 	} else {
 		for (i = 0; i < routes->len; i++) {
-			const NMPlatformIP6Route *r = NMP_OBJECT_CAST_IP6_ROUTE ((NMPObject *) routes->pdata[i]);
+			const NMPlatformIP6Route *r = NMP_OBJECT_CAST_IP6_ROUTE (routes->pdata[i]);
 
 			route.rx.rt_source = r->rt_source;
 			if (nm_platform_ip6_route_cmp (r, &route.r6) == 0)
@@ -346,7 +346,7 @@ _platform_route_sync_flush (const VTableIP *vtable, NMDefaultRouteManager *self,
 		gboolean has_ifindex_synced = FALSE;
 		Entry *entry = NULL;
 
-		route = NMP_OBJECT_CAST_IP_ROUTE ((NMPObject *) routes->pdata[i]);
+		route = NMP_OBJECT_CAST_IP_ROUTE (routes->pdata[i]);
 
 		/* look at all entries and see if the route for this ifindex pair is
 		 * a known entry. */
@@ -442,7 +442,7 @@ _get_assumed_interface_metrics (const VTableIP *vtable, NMDefaultRouteManager *s
 			gboolean ifindex_has_synced_entry = FALSE;
 			const NMPlatformIPRoute *route;
 
-			route = NMP_OBJECT_CAST_IP_ROUTE ((NMPObject *) routes->pdata[i]);
+			route = NMP_OBJECT_CAST_IP_ROUTE (routes->pdata[i]);
 
 			for (j = 0; j < entries->len; j++) {
 				Entry *e = g_ptr_array_index (entries, j);
@@ -571,7 +571,7 @@ _resync_all (const VTableIP *vtable, NMDefaultRouteManager *self, const Entry *c
 			/* However, if there is a matching route (ifindex+metric) for our current entry, we are done. */
 			if (routes) {
 				for (j = 0; j < routes->len; j++) {
-					const NMPlatformIPRoute *r = NMP_OBJECT_CAST_IP_ROUTE ((NMPObject *) routes->pdata[i]);
+					const NMPlatformIPRoute *r = NMP_OBJECT_CAST_IP_ROUTE (routes->pdata[i]);
 
 					if (   r->metric == expected_metric
 					    && r->ifindex == entry->route.rx.ifindex) {
diff --git a/src/nm-manager.c b/src/nm-manager.c
index dd168fd0be..3a8ada4360 100644
--- a/src/nm-manager.c
+++ b/src/nm-manager.c
@@ -2493,7 +2493,7 @@ platform_query_devices (NMManager *self)
 	if (!links)
 		return;
 	for (i = 0; i < links->len; i++) {
-		const NMPlatformLink *link = NMP_OBJECT_CAST_LINK ((const NMPObject *) links->pdata[i]);
+		const NMPlatformLink *link = NMP_OBJECT_CAST_LINK (links->pdata[i]);
 		gs_free NMConfigDeviceStateData *dev_state = NULL;
 
 		dev_state = nm_config_device_state_load (link->ifindex);
diff --git a/src/nm-route-manager.c b/src/nm-route-manager.c
index 8372d65234..e980cfe0a6 100644
--- a/src/nm-route-manager.c
+++ b/src/nm-route-manager.c
@@ -333,7 +333,7 @@ _route_index_create_from_platform (const VTableIP *vtable,
 
 	j = 0;
 	for (i = 0; i < len; i++) {
-		const NMPlatformIPXRoute *ipx_route = NMP_OBJECT_CAST_IPX_ROUTE ((NMPObject *) storage->pdata[i]);
+		const NMPlatformIPXRoute *ipx_route = NMP_OBJECT_CAST_IPX_ROUTE (storage->pdata[i]);
 
 		if (NM_PLATFORM_IP_ROUTE_IS_DEFAULT (ipx_route))
 			continue;
diff --git a/src/platform/nm-platform.c b/src/platform/nm-platform.c
index 73e508ff00..176f377bdb 100644
--- a/src/platform/nm-platform.c
+++ b/src/platform/nm-platform.c
@@ -527,7 +527,7 @@ nm_platform_link_get_all (NMPlatform *self, gboolean sort_by_name)
 
 	unseen = g_hash_table_new (g_direct_hash, g_direct_equal);
 	for (i = 0; i < links->len; i++) {
-		item = NMP_OBJECT_CAST_LINK ((const NMPObject *) links->pdata[i]);
+		item = NMP_OBJECT_CAST_LINK (links->pdata[i]);
 		nm_assert (item->ifindex > 0);
 		if (!nm_g_hash_table_insert (unseen, GINT_TO_POINTER (item->ifindex), NULL))
 			nm_assert_not_reached ();
@@ -536,7 +536,7 @@ nm_platform_link_get_all (NMPlatform *self, gboolean sort_by_name)
 #if NM_MORE_ASSERTS
 	/* Ensure that link_get_all returns a consistent and valid result. */
 	for (i = 0; i < links->len; i++) {
-		item = NMP_OBJECT_CAST_LINK ((const NMPObject *) links->pdata[i]);
+		item = NMP_OBJECT_CAST_LINK (links->pdata[i]);
 
 		if (!item->ifindex)
 			continue;
@@ -565,7 +565,7 @@ nm_platform_link_get_all (NMPlatform *self, gboolean sort_by_name)
 		guint first_idx = G_MAXUINT;
 
 		for (i = 0; i < links->len; i++) {
-			item = NMP_OBJECT_CAST_LINK ((const NMPObject *) links->pdata[i]);
+			item = NMP_OBJECT_CAST_LINK (links->pdata[i]);
 
 			if (!item)
 				continue;
@@ -594,7 +594,7 @@ skip:
 			nm_assert (first_idx != G_MAXUINT);
 			/* There is a loop, pop the first (remaining) element from the list.
 			 * This can happen for veth pairs where each peer is parent of the other end. */
-			item = NMP_OBJECT_CAST_LINK ((const NMPObject *) links->pdata[first_idx]);
+			item = NMP_OBJECT_CAST_LINK (links->pdata[first_idx]);
 			g_hash_table_remove (unseen, GINT_TO_POINTER (item->ifindex));
 			g_ptr_array_add (result, links->pdata[first_idx]);
 			links->pdata[first_idx] = NULL;
diff --git a/src/platform/nmp-object.h b/src/platform/nmp-object.h
index 9ea5a78ae5..9cdad2e808 100644
--- a/src/platform/nmp-object.h
+++ b/src/platform/nmp-object.h
@@ -339,65 +339,58 @@ NMP_OBJECT_GET_TYPE (const NMPObject *obj)
 
 #define NMP_OBJECT_CAST_LINK(obj) \
 	({ \
-		typeof (*(obj)) *_obj = (obj); \
-		_nm_unused const NMPObject *_obj_type_check = _obj; \
+		typeof (obj) _obj = (obj); \
 		\
-		nm_assert (!_obj || NMP_OBJECT_GET_TYPE (_obj) == NMP_OBJECT_TYPE_LINK); \
-		_obj ? &_obj->link : NULL; \
+		nm_assert (!_obj || NMP_OBJECT_GET_TYPE ((const NMPObject *) _obj) == NMP_OBJECT_TYPE_LINK); \
+		_obj ? &_NM_CONSTCAST (NMPObject, _obj)->link : NULL; \
 	})
 
 #define NMP_OBJECT_CAST_IP4_ADDRESS(obj) \
 	({ \
-		typeof (*(obj)) *_obj = (obj); \
-		_nm_unused const NMPObject *_obj_type_check = _obj; \
+		typeof (obj) _obj = (obj); \
 		\
-		nm_assert (!_obj || NMP_OBJECT_GET_TYPE (_obj) == NMP_OBJECT_TYPE_IP4_ADDRESS); \
-		_obj ? &_obj->ip4_address : NULL; \
+		nm_assert (!_obj || NMP_OBJECT_GET_TYPE ((const NMPObject *) _obj) == NMP_OBJECT_TYPE_IP4_ADDRESS); \
+		_obj ? &_NM_CONSTCAST (NMPObject, _obj)->ip4_address : NULL; \
 	})
 
 #define NMP_OBJECT_CAST_IP6_ADDRESS(obj) \
 	({ \
-		typeof (*(obj)) *_obj = (obj); \
-		_nm_unused const NMPObject *_obj_type_check = _obj; \
+		typeof (obj) _obj = (obj); \
 		\
-		nm_assert (!_obj || NMP_OBJECT_GET_TYPE (_obj) == NMP_OBJECT_TYPE_IP6_ADDRESS); \
-		_obj ? &_obj->ip6_address : NULL; \
+		nm_assert (!_obj || NMP_OBJECT_GET_TYPE ((const NMPObject *) _obj) == NMP_OBJECT_TYPE_IP6_ADDRESS); \
+		_obj ? &_NM_CONSTCAST (NMPObject, _obj)->ip6_address : NULL; \
 	})
 
 #define NMP_OBJECT_CAST_IPX_ROUTE(obj) \
 	({ \
-		typeof (*(obj)) *_obj = (obj); \
-		_nm_unused const NMPObject *_obj_type_check = _obj; \
+		typeof (obj) _obj = (obj); \
 		\
-		nm_assert (NM_IN_SET (NMP_OBJECT_GET_TYPE (_obj), NMP_OBJECT_TYPE_IP4_ROUTE, NMP_OBJECT_TYPE_IP6_ROUTE)); \
-		&_obj->ipx_route; \
+		nm_assert (!_obj || NM_IN_SET (NMP_OBJECT_GET_TYPE (_obj), NMP_OBJECT_TYPE_IP4_ROUTE, NMP_OBJECT_TYPE_IP6_ROUTE)); \
+		_obj ? &_NM_CONSTCAST (NMPObject, _obj)->ipx_route : NULL; \
 	})
 
 #define NMP_OBJECT_CAST_IP_ROUTE(obj) \
 	({ \
-		typeof (*(obj)) *_obj = (obj); \
-		_nm_unused const NMPObject *_obj_type_check = _obj; \
+		typeof (obj) _obj = (obj); \
 		\
-		nm_assert (NM_IN_SET (NMP_OBJECT_GET_TYPE (_obj), NMP_OBJECT_TYPE_IP4_ROUTE, NMP_OBJECT_TYPE_IP6_ROUTE)); \
-		&_obj->ip_route; \
+		nm_assert (!_obj || NM_IN_SET (NMP_OBJECT_GET_TYPE (_obj), NMP_OBJECT_TYPE_IP4_ROUTE, NMP_OBJECT_TYPE_IP6_ROUTE)); \
+		_obj ? &_NM_CONSTCAST (NMPObject, _obj)->ip_route : NULL; \
 	})
 
 #define NMP_OBJECT_CAST_IP4_ROUTE(obj) \
 	({ \
-		typeof (*(obj)) *_obj = (obj); \
-		_nm_unused const NMPObject *_obj_type_check = _obj; \
+		typeof (obj) _obj = (obj); \
 		\
-		nm_assert (NMP_OBJECT_GET_TYPE (_obj) == NMP_OBJECT_TYPE_IP4_ROUTE); \
-		&_obj->ip4_route; \
+		nm_assert (!_obj || NMP_OBJECT_GET_TYPE ((const NMPObject *) _obj) == NMP_OBJECT_TYPE_IP4_ROUTE); \
+		_obj ? &_NM_CONSTCAST (NMPObject, _obj)->ip4_route : NULL; \
 	})
 
 #define NMP_OBJECT_CAST_IP6_ROUTE(obj) \
 	({ \
-		typeof (*(obj)) *_obj = (obj); \
-		_nm_unused const NMPObject *_obj_type_check = _obj; \
+		typeof (obj) _obj = (obj); \
 		\
-		nm_assert (NMP_OBJECT_GET_TYPE (_obj) == NMP_OBJECT_TYPE_IP6_ROUTE); \
-		&_obj->ip6_route; \
+		nm_assert (!_obj || NMP_OBJECT_GET_TYPE ((const NMPObject *) _obj) == NMP_OBJECT_TYPE_IP6_ROUTE); \
+		_obj ? &_NM_CONSTCAST (NMPObject, _obj)->ip6_route : NULL; \
 	})
 
 const NMPClass *nmp_class_from_type (NMPObjectType obj_type);