rerere: check dirname format while iterating rr_cache directory
In rerere_gc(), we walk over the .git/rr_cache directory and create a
struct for each entry we find. We feed any name we get from readdir() to
find_rerere_dir(), which then calls get_sha1_hex() on it (since we use
the binary hash as a lookup key). If that fails (i.e., the directory
name is not what we expected), it returns NULL. But the comment in
find_rerere_dir() says "BUG".
It _would_ be a bug for the call from new_rerere_id_hex(), the only
other code path, to fail here; it's generating the hex internally. But
the call in rerere_gc() is using it say "is this a plausible directory
name".
Let's instead have rerere_gc() do its own "is this plausible" check.
That has two benefits:
- we can now reliably BUG() inside find_rerere_dir(), which would
catch bugs in the other code path (and we now will never return NULL
from the function, which makes it easier to see that a rerere_id
struct will always have a non-NULL "collection" field).
- it makes the use of the binary hash an implementation detail of
find_rerere_dir(), not known by callers. That will free us up to
change it in a future patch.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/rerere.c b/rerere.c
index d6928c1..7b0c262 100644
--- a/rerere.c
+++ b/rerere.c
@@ -146,7 +146,7 @@ static struct rerere_dir *find_rerere_dir(const char *hex)
int pos;
if (get_sha1_hex(hex, hash))
- return NULL; /* BUG */
+ BUG("cannot parse rerere dir hex?");
pos = hash_pos(hash, rerere_dir, rerere_dir_nr, rerere_dir_hash);
if (pos < 0) {
rr_dir = xmalloc(sizeof(*rr_dir));
@@ -1178,6 +1178,13 @@ static void prune_one(struct rerere_id *id,
unlink_rr_item(id);
}
+/* Does the basename in "path" look plausibly like an rr-cache entry? */
+static int is_rr_cache_dirname(const char *path)
+{
+ unsigned char hash[GIT_MAX_RAWSZ];
+ return !get_sha1_hex(path, hash);
+}
+
void rerere_gc(struct repository *r, struct string_list *rr)
{
struct string_list to_remove = STRING_LIST_INIT_DUP;
@@ -1205,10 +1212,11 @@ void rerere_gc(struct repository *r, struct string_list *rr)
if (is_dot_or_dotdot(e->d_name))
continue;
- rr_dir = find_rerere_dir(e->d_name);
- if (!rr_dir)
+ if (!is_rr_cache_dirname(e->d_name))
continue; /* or should we remove e->d_name? */
+ rr_dir = find_rerere_dir(e->d_name);
+
now_empty = 1;
for (id.variant = 0, id.collection = rr_dir;
id.variant < id.collection->status_nr;
