tree-wide: expose "p"-suffix unref calls in public APIs to make gcc cleanup easy

GLIB has recently started to officially support the gcc cleanup
attribute in its public API, hence let's do the same for our APIs.

With this patch we'll define an xyz_unrefp() call for each public
xyz_unref() call, to make it easy to use inside a
__attribute__((cleanup())) expression. Then, all code is ported over to
make use of this.

The new calls are also documented in the man pages, with examples how to
use them (well, I only added docs where the _unref() call itself already
had docs, and the examples, only cover sd_bus_unrefp() and
sd_event_unrefp()).

This also renames sd_lldp_free() to sd_lldp_unref(), since that's how we
tend to call our destructors these days.

Note that this defines no public macro that wraps gcc's attribute and
makes it easier to use. While I think it's our duty in the library to
make our stuff easy to use, I figure it's not our duty to make gcc's own
features easy to use on its own. Most likely, client code which wants to
make use of this should define its own:

       #define _cleanup_(function) __attribute__((cleanup(function)))

Or similar, to make the gcc feature easier to use.

Making this logic public has the benefit that we can remove three header
files whose only purpose was to define these functions internally.

See #2008.

2 files changed, 2 insertions, 2 deletions

diff --git a/src/libudev/libudev-enumerate.c b/src/libudev/libudev-enumerate.c
index 442f9615f2..e416e178b4 100644
--- a/src/libudev/libudev-enumerate.c
+++ b/src/libudev/libudev-enumerate.c
@@ -370,7 +370,7 @@ _public_ int udev_enumerate_add_match_sysname(struct udev_enumerate *udev_enumer
  * Returns: 0 on success, otherwise a negative error value.
  */
 _public_ int udev_enumerate_add_syspath(struct udev_enumerate *udev_enumerate, const char *syspath) {
-        _cleanup_device_unref_ sd_device *device = NULL;
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
         int r;
 
         assert_return(udev_enumerate, -EINVAL);
diff --git a/src/libudev/libudev-hwdb.c b/src/libudev/libudev-hwdb.c
index eba698d163..a53f000015 100644
--- a/src/libudev/libudev-hwdb.c
+++ b/src/libudev/libudev-hwdb.c
@@ -53,7 +53,7 @@ struct udev_hwdb {
  * Returns: a hwdb context.
  **/
 _public_ struct udev_hwdb *udev_hwdb_new(struct udev *udev) {
-        _cleanup_hwdb_unref_ sd_hwdb *hwdb_internal = NULL;
+        _cleanup_(sd_hwdb_unrefp) sd_hwdb *hwdb_internal = NULL;
         struct udev_hwdb *hwdb;
         int r;