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.

4 files changed, 8 insertions, 11 deletions

diff --git a/src/import/export.c b/src/import/export.c
index 2b33d778d3..27efc3b099 100644
--- a/src/import/export.c
+++ b/src/import/export.c
@@ -24,7 +24,6 @@
 #include "sd-event.h"
 
 #include "alloc-util.h"
-#include "event-util.h"
 #include "export-raw.h"
 #include "export-tar.h"
 #include "fd-util.h"
@@ -76,7 +75,7 @@ static void on_tar_finished(TarExport *export, int error, void *userdata) {
 
 static int export_tar(int argc, char *argv[], void *userdata) {
         _cleanup_(tar_export_unrefp) TarExport *export = NULL;
-        _cleanup_event_unref_ sd_event *event = NULL;
+        _cleanup_(sd_event_unrefp) sd_event *event = NULL;
         _cleanup_(image_unrefp) Image *image = NULL;
         const char *path = NULL, *local = NULL;
         _cleanup_close_ int open_fd = -1;
@@ -155,7 +154,7 @@ static void on_raw_finished(RawExport *export, int error, void *userdata) {
 
 static int export_raw(int argc, char *argv[], void *userdata) {
         _cleanup_(raw_export_unrefp) RawExport *export = NULL;
-        _cleanup_event_unref_ sd_event *event = NULL;
+        _cleanup_(sd_event_unrefp) sd_event *event = NULL;
         _cleanup_(image_unrefp) Image *image = NULL;
         const char *path = NULL, *local = NULL;
         _cleanup_close_ int open_fd = -1;
diff --git a/src/import/import.c b/src/import/import.c
index 018b94d4c4..15505de924 100644
--- a/src/import/import.c
+++ b/src/import/import.c
@@ -24,7 +24,6 @@
 #include "sd-event.h"
 
 #include "alloc-util.h"
-#include "event-util.h"
 #include "fd-util.h"
 #include "fs-util.h"
 #include "hostname-util.h"
@@ -58,7 +57,7 @@ static void on_tar_finished(TarImport *import, int error, void *userdata) {
 
 static int import_tar(int argc, char *argv[], void *userdata) {
         _cleanup_(tar_import_unrefp) TarImport *import = NULL;
-        _cleanup_event_unref_ sd_event *event = NULL;
+        _cleanup_(sd_event_unrefp) sd_event *event = NULL;
         const char *path = NULL, *local = NULL;
         _cleanup_free_ char *ll = NULL;
         _cleanup_close_ int open_fd = -1;
@@ -153,7 +152,7 @@ static void on_raw_finished(RawImport *import, int error, void *userdata) {
 
 static int import_raw(int argc, char *argv[], void *userdata) {
         _cleanup_(raw_import_unrefp) RawImport *import = NULL;
-        _cleanup_event_unref_ sd_event *event = NULL;
+        _cleanup_(sd_event_unrefp) sd_event *event = NULL;
         const char *path = NULL, *local = NULL;
         _cleanup_free_ char *ll = NULL;
         _cleanup_close_ int open_fd = -1;
diff --git a/src/import/importd.c b/src/import/importd.c
index 4228681cea..1f308b36b3 100644
--- a/src/import/importd.c
+++ b/src/import/importd.c
@@ -1039,7 +1039,7 @@ static int method_pull_dkr(sd_bus_message *msg, void *userdata, sd_bus_error *er
 }
 
 static int method_list_transfers(sd_bus_message *msg, void *userdata, sd_bus_error *error) {
-        _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
         Manager *m = userdata;
         Transfer *t;
         Iterator i;
diff --git a/src/import/pull.c b/src/import/pull.c
index 39f5b2d8e4..fc93228a0b 100644
--- a/src/import/pull.c
+++ b/src/import/pull.c
@@ -24,7 +24,6 @@
 #include "sd-event.h"
 
 #include "alloc-util.h"
-#include "event-util.h"
 #include "hostname-util.h"
 #include "import-util.h"
 #include "machine-image.h"
@@ -61,7 +60,7 @@ static void on_tar_finished(TarPull *pull, int error, void *userdata) {
 
 static int pull_tar(int argc, char *argv[], void *userdata) {
         _cleanup_(tar_pull_unrefp) TarPull *pull = NULL;
-        _cleanup_event_unref_ sd_event *event = NULL;
+        _cleanup_(sd_event_unrefp) sd_event *event = NULL;
         const char *url, *local;
         _cleanup_free_ char *l = NULL, *ll = NULL;
         int r;
@@ -147,7 +146,7 @@ static void on_raw_finished(RawPull *pull, int error, void *userdata) {
 
 static int pull_raw(int argc, char *argv[], void *userdata) {
         _cleanup_(raw_pull_unrefp) RawPull *pull = NULL;
-        _cleanup_event_unref_ sd_event *event = NULL;
+        _cleanup_(sd_event_unrefp) sd_event *event = NULL;
         const char *url, *local;
         _cleanup_free_ char *l = NULL, *ll = NULL;
         int r;
@@ -233,7 +232,7 @@ static void on_dkr_finished(DkrPull *pull, int error, void *userdata) {
 
 static int pull_dkr(int argc, char *argv[], void *userdata) {
         _cleanup_(dkr_pull_unrefp) DkrPull *pull = NULL;
-        _cleanup_event_unref_ sd_event *event = NULL;
+        _cleanup_(sd_event_unrefp) sd_event *event = NULL;
         const char *name, *reference, *local, *digest;
         int r;