basic/set: let set_put_strdup() create the set with string hash ops

If we're using a set with _put_strdup(), most of the time we want to use
string hash ops on the set, and free the strings when done. This defines
the appropriate a new string_hash_ops_free structure to automatically free
the keys when removing the set, and makes set_put_strdup() and set_put_strdupv()
instantiate the set with those hash ops.

hashmap_put_strdup() was already doing something similar.

(It is OK to instantiate the set earlier, possibly with a different hash ops
structure. set_put_strdup() will then use the existing set. It is also OK
to call set_free_free() instead of set_free() on a set with
string_hash_ops_free, the effect is the same, we're just overriding the
override of the cleanup function.)

No functional change intended.

src/shared/bus-util.c

@@ -1695,14 +1695,10 @@ int bus_introspect_implementations(
         if (impl != main_impl)
                 bus_introspect_implementation(&intro, impl);
 
-        _cleanup_set_free_free_ Set *nodes = NULL;
+        _cleanup_set_free_ Set *nodes = NULL;
 
         for (size_t i = 0; impl->children && impl->children[i]; i++) {
-                r = set_ensure_allocated(&nodes, &string_hash_ops);
-                if (r < 0)
-                        return log_oom();
-
-                r = set_put_strdup(nodes, impl->children[i]->path);
+                r = set_put_strdup(&nodes, impl->children[i]->path);
                 if (r < 0)
                         return log_oom();
         }

src/shared/bus-wait-for-jobs.c

@@ -65,7 +65,7 @@ void bus_wait_for_jobs_free(BusWaitForJobs *d) {
         if (!d)
                 return;
 
-        set_free_free(d->jobs);
+        set_free(d->jobs);
 
         sd_bus_slot_unref(d->slot_disconnected);
         sd_bus_slot_unref(d->slot_job_removed);
@@ -315,15 +315,9 @@ int bus_wait_for_jobs(BusWaitForJobs *d, bool quiet, const char* const* extra_ar
 }
 
 int bus_wait_for_jobs_add(BusWaitForJobs *d, const char *path) {
-        int r;
-
         assert(d);
 
-        r = set_ensure_allocated(&d->jobs, &string_hash_ops);
-        if (r < 0)
-                return r;
-
-        return set_put_strdup(d->jobs, path);
+        return set_put_strdup(&d->jobs, path);
 }
 
 int bus_wait_for_jobs_one(BusWaitForJobs *d, const char *path, bool quiet) {

src/shared/logs-show.c

@@ -1133,30 +1133,25 @@ int show_journal_entry(
                 const size_t highlight[2],
                 bool *ellipsized) {
 
-        int ret;
-        _cleanup_set_free_free_ Set *fields = NULL;
+        _cleanup_set_free_ Set *fields = NULL;
+        int r;
+
         assert(mode >= 0);
         assert(mode < _OUTPUT_MODE_MAX);
 
         if (n_columns <= 0)
                 n_columns = columns();
 
-        if (output_fields) {
-                fields = set_new(&string_hash_ops);
-                if (!fields)
-                        return log_oom();
+        r = set_put_strdupv(&fields, output_fields);
+        if (r < 0)
+                return r;
 
-                ret = set_put_strdupv(fields, output_fields);
-                if (ret < 0)
-                        return ret;
-        }
+        r = output_funcs[mode](f, j, mode, n_columns, flags, fields, highlight);
 
-        ret = output_funcs[mode](f, j, mode, n_columns, flags, fields, highlight);
-
-        if (ellipsized && ret > 0)
+        if (ellipsized && r > 0)
                 *ellipsized = true;
 
-        return ret;
+        return r;
 }
 
 static int maybe_print_begin_newline(FILE *f, OutputFlags *flags) {

src/shared/mount-util.c

@@ -239,7 +239,7 @@ int bind_remount_recursive_with_mountinfo(
                         }
 
                         if (!set_contains(done, path)) {
-                                r = set_put_strdup(todo, path);
+                                r = set_put_strdup(&todo, path);
                                 if (r < 0)
                                         return r;
                         }
@@ -266,7 +266,7 @@ int bind_remount_recursive_with_mountinfo(
 
                         log_debug("Made top-level directory %s a mount point.", prefix);
 
-                        r = set_put_strdup(done, simplified);
+                        r = set_put_strdup(&done, simplified);
                         if (r < 0)
                                 return r;
                 }

src/shared/unit-file.c

@@ -463,7 +463,7 @@ int unit_file_find_fragment(
 
         /* The unit always has its own name if it's not a template. */
         if (IN_SET(name_type, UNIT_NAME_PLAIN, UNIT_NAME_INSTANCE)) {
-                r = set_put_strdup(names, unit_name);
+                r = set_put_strdup(&names, unit_name);
                 if (r < 0)
                         return r;
         }
@@ -493,7 +493,7 @@ int unit_file_find_fragment(
                                 if (!streq(unit_name, *t))
                                         log_debug("%s: %s has alias %s", __func__, unit_name, *t);
 
-                                r = set_put_strdup(names, *t);
+                                r = set_put_strdup(&names, *t);
                         }
                         if (r < 0)
                                 return r;