[PATCH v2 04/14] describe: use commit-slab for commit names instead of commit->util

[Nguyễn Thái Ngọc Duy]

It's done so that commit->util can be removed. See more explanation in
the commit that removes commit->util.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclo...@gmail.com>
---
 builtin/describe.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/builtin/describe.c b/builtin/describe.c
index b5afc45846..1b6ca42553 100644
--- a/builtin/describe.c
+++ b/builtin/describe.c
@@ -15,9 +15,12 @@
 #include "run-command.h"
 #include "revision.h"
 #include "list-objects.h"
+#include "commit-slab.h"
 
 #define MAX_TAGS       (FLAG_BITS - 1)
 
+define_commit_slab(commit_names, struct commit_name *);
+
 static const char * const describe_usage[] = {
        N_("git describe [<options>] [<commit-ish>...]"),
        N_("git describe [<options>] --dirty"),
@@ -37,6 +40,7 @@ static struct string_list patterns = STRING_LIST_INIT_NODUP;
 static struct string_list exclude_patterns = STRING_LIST_INIT_NODUP;
 static int always;
 static const char *suffix, *dirty, *broken;
+static struct commit_names commit_names;
 
 /* diff-index command arguments to check if working tree is dirty. */
 static const char *diff_index_args[] = {
@@ -321,11 +325,14 @@ static void describe_commit(struct object_id *oid, struct 
strbuf *dst)
        if (!have_util) {
                struct hashmap_iter iter;
                struct commit *c;
-               struct commit_name *n = hashmap_iter_first(&names, &iter);
+               struct commit_name *n;
+
+               init_commit_names(&commit_names);
+               n = hashmap_iter_first(&names, &iter);
                for (; n; n = hashmap_iter_next(&iter)) {
                        c = lookup_commit_reference_gently(&n->peeled, 1);
                        if (c)
-                               c->util = n;
+                               *commit_names_at(&commit_names, c) = n;
                }
                have_util = 1;
        }
@@ -336,8 +343,11 @@ static void describe_commit(struct object_id *oid, struct 
strbuf *dst)
        while (list) {
                struct commit *c = pop_commit(&list);
                struct commit_list *parents = c->parents;
+               struct commit_name **slot;
+
                seen_commits++;
-               n = c->util;
+               slot = commit_names_peek(&commit_names, c);
+               n = slot ? *slot : NULL;
                if (n) {
                        if (!tags && !all && n->prio < 2) {
                                unannotated_cnt++;
-- 
2.17.0.705.g3525833791