object-name.c: refactor find_unique_abbrev_len into its own exported function

This commit makes it easier to determine the length of the hash that git log --oneline or git log --pretty will print. * object-name.c: refactor finding abbreviated sha length into its own function * cache.h: expose function find_unique_abbrev_len Signed-off-by: John Cai <johncai86@gmail.com>

Author: john-cai

cache.h

@@ -1147,6 +1147,7 @@ const char *repo_find_unique_abbrev(struct repository *r, const struct object_id
 #define find_unique_abbrev(oid, len) repo_find_unique_abbrev(the_repository, oid, len)
 int repo_find_unique_abbrev_r(struct repository *r, char *hex, const struct object_id *oid, int len);
 #define find_unique_abbrev_r(hex, oid, len) repo_find_unique_abbrev_r(the_repository, hex, oid, len)
+int find_unique_abbrev_len(struct repository *r, int len);
 
 /* set default permissions by passing mode arguments to open(2) */
 int git_mkstemps_mode(char *pattern, int suffix_len, int mode);

object-name.c

@@ -660,14 +660,8 @@ static void find_abbrev_len_packed(struct min_abbrev_data *mad)
 find_abbrev_len_for_pack(p, mad);
 }
 
-int repo_find_unique_abbrev_r(struct repository *r, char *hex,
- const struct object_id *oid, int len)
+int find_unique_abbrev_len(struct repository *r, int len)
 {
-struct disambiguate_state ds;
-struct min_abbrev_data mad;
-struct object_id oid_ret;
-const unsigned hexsz = r->hash_algo->hexsz;
-
 if (len < 0) {
 unsigned long count = repo_approximate_object_count(r);
 /*
@@ -690,6 +684,19 @@ int repo_find_unique_abbrev_r(struct repository *r, char *hex,
 len = FALLBACK_DEFAULT_ABBREV;
 }
 
+return len;
+}
+
+int repo_find_unique_abbrev_r(struct repository *r, char *hex,
+ const struct object_id *oid, int len)
+{
+struct disambiguate_state ds;
+struct min_abbrev_data mad;
+struct object_id oid_ret;
+const unsigned hexsz = r->hash_algo->hexsz;
+
+len = find_unique_abbrev_len(r, len);
+
 oid_to_hex_r(hex, oid);
 if (len == hexsz || !len)
 return hexsz;