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.

1 files changed, 17 insertions, 15 deletions

diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
index 99780c8cce..3c2232a354 100644
--- a/src/libsystemd/sd-bus/sd-bus.c
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -419,7 +419,7 @@ static int hello_callback(sd_bus_message *reply, void *userdata, sd_bus_error *e
 }
 
 static int bus_send_hello(sd_bus *bus) {
-        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
         int r;
 
         assert(bus);
@@ -1480,7 +1480,9 @@ static void bus_enter_closing(sd_bus *bus) {
 }
 
 _public_ sd_bus *sd_bus_ref(sd_bus *bus) {
-        assert_return(bus, NULL);
+
+        if (!bus)
+                return NULL;
 
         assert_se(REFCNT_INC(bus->n_ref) >= 2);
 
@@ -1734,7 +1736,7 @@ static int dispatch_rqueue(sd_bus *bus, bool hint_priority, int64_t priority, sd
 }
 
 static int bus_send_internal(sd_bus *bus, sd_bus_message *_m, uint64_t *cookie, bool hint_sync_call) {
-        _cleanup_bus_message_unref_ sd_bus_message *m = sd_bus_message_ref(_m);
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = sd_bus_message_ref(_m);
         int r;
 
         assert_return(m, -EINVAL);
@@ -1882,8 +1884,8 @@ _public_ int sd_bus_call_async(
                 void *userdata,
                 uint64_t usec) {
 
-        _cleanup_bus_message_unref_ sd_bus_message *m = sd_bus_message_ref(_m);
-        _cleanup_bus_slot_unref_ sd_bus_slot *s = NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = sd_bus_message_ref(_m);
+        _cleanup_(sd_bus_slot_unrefp) sd_bus_slot *s = NULL;
         int r;
 
         assert_return(m, -EINVAL);
@@ -1981,7 +1983,7 @@ _public_ int sd_bus_call(
                 sd_bus_error *error,
                 sd_bus_message **reply) {
 
-        _cleanup_bus_message_unref_ sd_bus_message *m = sd_bus_message_ref(_m);
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = sd_bus_message_ref(_m);
         usec_t timeout;
         uint64_t cookie;
         unsigned i;
@@ -2220,8 +2222,8 @@ _public_ int sd_bus_get_timeout(sd_bus *bus, uint64_t *timeout_usec) {
 }
 
 static int process_timeout(sd_bus *bus) {
-        _cleanup_bus_error_free_ sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
-        _cleanup_bus_message_unref_ sd_bus_message* m = NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message* m = NULL;
         struct reply_callback *c;
         sd_bus_slot *slot;
         usec_t n;
@@ -2302,8 +2304,8 @@ static int process_hello(sd_bus *bus, sd_bus_message *m) {
 }
 
 static int process_reply(sd_bus *bus, sd_bus_message *m) {
-        _cleanup_bus_message_unref_ sd_bus_message *synthetic_reply = NULL;
-        _cleanup_bus_error_free_ sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *synthetic_reply = NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
         struct reply_callback *c;
         sd_bus_slot *slot;
         int r;
@@ -2382,7 +2384,7 @@ static int process_reply(sd_bus *bus, sd_bus_message *m) {
 }
 
 static int process_filter(sd_bus *bus, sd_bus_message *m) {
-        _cleanup_bus_error_free_ sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
         struct filter_callback *l;
         int r;
 
@@ -2448,7 +2450,7 @@ static int process_match(sd_bus *bus, sd_bus_message *m) {
 }
 
 static int process_builtin(sd_bus *bus, sd_bus_message *m) {
-        _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
         int r;
 
         assert(bus);
@@ -2580,7 +2582,7 @@ static int dispatch_track(sd_bus *bus) {
 }
 
 static int process_running(sd_bus *bus, bool hint_priority, int64_t priority, sd_bus_message **ret) {
-        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
         int r;
 
         assert(bus);
@@ -2644,7 +2646,7 @@ null_message:
 }
 
 static int process_closing(sd_bus *bus, sd_bus_message **ret) {
-        _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
         struct reply_callback *c;
         int r;
 
@@ -2653,7 +2655,7 @@ static int process_closing(sd_bus *bus, sd_bus_message **ret) {
 
         c = ordered_hashmap_first(bus->reply_callbacks);
         if (c) {
-                _cleanup_bus_error_free_ sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
+                _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
                 sd_bus_slot *slot;
 
                 /* First, fail all outstanding method calls */