sha1-file: add functions for hex empty tree and blob OIDs

Oftentimes, we'll want to refer to an empty tree or empty blob by its
hex name without having to call oid_to_hex or explicitly refer to
the_hash_algo.  Add helper functions that format these values into
static buffers and return them for easy use.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/cache.h b/cache.h
index 9ad1dd2ddc3c39d32d610a28dc8a6aeb1ae55f36..14690c84a277a0ab5cbdab3742f9ef909b8da00c 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -1049,6 +1049,9 @@ static inline int is_empty_tree_oid(const struct object_id *oid)
        return !oidcmp(oid, the_hash_algo->empty_tree);
 }
 
+const char *empty_tree_oid_hex(void);
+const char *empty_blob_oid_hex(void);
+
 /* set default permissions by passing mode arguments to open(2) */
 int git_mkstemps_mode(char *pattern, int suffix_len, int mode);
 int git_mkstemp_mode(char *pattern, int mode);

diff --git a/sha1_file.c b/sha1_file.c
index 4328c6128566d4f9666bf6cbd2642f090034df0b..11598b43eba73f7649ec8c9b3b4c5e0f2e98e270 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -100,6 +100,18 @@ const struct git_hash_algo hash_algos[GIT_HASH_NALGOS] = {
        },
 };
 
+const char *empty_tree_oid_hex(void)
+{
+       static char buf[GIT_MAX_HEXSZ + 1];
+       return oid_to_hex_r(buf, the_hash_algo->empty_tree);
+}
+
+const char *empty_blob_oid_hex(void)
+{
+       static char buf[GIT_MAX_HEXSZ + 1];
+       return oid_to_hex_r(buf, the_hash_algo->empty_blob);
+}
+
 /*
  * This is meant to hold a *small* number of objects that you would
  * want read_sha1_file() to be able to return, but yet you do not want