[PATCH 11/12] server-info: drop objdirlen pointer arithmetic

[Jeff King <peff@peff.net>]

When writing objects/info/packs, we use the basename of each pack
(i.e., just the "pack-1234abcd.pack" part). We compute that manually by
adding "objdirlen + 6" to the name.

This _should_ work consistently, as we do not include non-local packs,
meaning everything should be in $objdir/pack/. Before f13d7db4af
(server-info.c: use pack_local like everybody else., 2005-12-05), this
was definitely true, since we computed "local" based on comparing the
objdir string.  Since then, we're relying on the code on packfile.c to
match our expectations of p->pack_name and p->local.

I think our expectations do still hold today, but we can be a bit more
defensive by just using pack_basename() to get the base. That
future-proofs us, and should hopefully be more obviously safe to
somebody reading the code.

Signed-off-by: Jeff King <peff@peff.net>
---
 packfile.c    |  2 +-
 packfile.h    |  6 ++++++
 server-info.c | 10 ++--------
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/packfile.c b/packfile.c
index e7ca135ed5..a0f92b7eef 100644
--- a/packfile.c
+++ b/packfile.c
@@ -472,7 +472,7 @@ static unsigned int get_max_fd_limit(void)
 #endif
 }
 
-static const char *pack_basename(struct packed_git *p)
+const char *pack_basename(struct packed_git *p)
 {
 	const char *ret = strrchr(p->pack_name, '/');
 	if (ret)
diff --git a/packfile.h b/packfile.h
index b40fc34fb2..45bf792d79 100644
--- a/packfile.h
+++ b/packfile.h
@@ -31,6 +31,12 @@ char *sha1_pack_name(const unsigned char *sha1);
  */
 char *sha1_pack_index_name(const unsigned char *sha1);
 
+/*
+ * Return the basename of the packfile, omitting any containing directory
+ * (e.g., "pack-1234abcd[...].pack").
+ */
+const char *pack_basename(struct packed_git *p);
+
 struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path);
 
 typedef void each_file_in_pack_dir_fn(const char *full_path, size_t full_path_len,
diff --git a/server-info.c b/server-info.c
index c9fbfd3a51..ab03c1b3c2 100644
--- a/server-info.c
+++ b/server-info.c
@@ -93,16 +93,13 @@ static struct pack_info {
 	int new_num;
 } **info;
 static int num_pack;
-static const char *objdir;
-static int objdirlen;
 
 static struct pack_info *find_pack_by_name(const char *name)
 {
 	int i;
 	for (i = 0; i < num_pack; i++) {
 		struct packed_git *p = info[i]->p;
-		/* skip "/pack/" after ".git/objects" */
-		if (!strcmp(p->pack_name + objdirlen + 6, name))
+		if (!strcmp(pack_basename(p), name))
 			return info[i];
 	}
 	return NULL;
@@ -196,9 +193,6 @@ static void init_pack_info(const char *infofile, int force)
 	int stale;
 	int i = 0;
 
-	objdir = get_object_directory();
-	objdirlen = strlen(objdir);
-
 	for (p = get_all_packs(the_repository); p; p = p->next) {
 		/* we ignore things on alternate path since they are
 		 * not available to the pullers in general.
@@ -246,7 +240,7 @@ static int write_pack_info_file(FILE *fp)
 {
 	int i;
 	for (i = 0; i < num_pack; i++) {
-		if (fprintf(fp, "P %s\n", info[i]->p->pack_name + objdirlen + 6) < 0)
+		if (fprintf(fp, "P %s\n", pack_basename(info[i]->p)) < 0)
 			return -1;
 	}
 	if (fputc('\n', fp) == EOF)
-- 
2.21.0.714.gd1be1d035b