diff options
author | Michael Haggerty <mhagger@alum.mit.edu> | 2013-03-18 15:37:32 +0400 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2013-03-18 19:06:28 +0400 |
commit | c29c46fa2e21e608ce2e603649af5bf38e7969c2 (patch) | |
tree | 80f08454a52aac4afe31b7bf0c7cb9c82bce417a /refs.c | |
parent | 03a8eddfd1bd7cdce0b2361753691f53c00e5ba6 (diff) |
pack-refs: add fully-peeled trait
Older versions of pack-refs did not write peel lines for
refs outside of refs/tags. This meant that on reading the
pack-refs file, we might set the REF_KNOWS_PEELED flag for
such a ref, even though we do not know anything about its
peeled value.
The previous commit updated the writer to always peel, no
matter what the ref is. That means that packed-refs files
written by newer versions of git are fine to be read by both
old and new versions of git. However, we still have the
problem of reading packed-refs files written by older
versions of git, or by other implementations which have not
yet learned the same trick.
The simplest fix would be to always unset the
REF_KNOWS_PEELED flag for refs outside of refs/tags that do
not have a peel line (if it has a peel line, we know it is
valid, but we cannot assume a missing peel line means
anything). But that loses an important optimization, as
upload-pack should not need to load the object pointed to by
refs/heads/foo to determine that it is not a tag.
Instead, we add a "fully-peeled" trait to the packed-refs
file. If it is set, we know that we can trust a missing peel
line to mean that a ref cannot be peeled. Otherwise, we fall
back to assuming nothing.
[commit message and tests by Jeff King <peff@peff.net>]
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'refs.c')
-rw-r--r-- | refs.c | 49 |
1 files changed, 44 insertions, 5 deletions
@@ -804,11 +804,38 @@ static const char *parse_ref_line(char *line, unsigned char *sha1) return line; } +/* + * Read f, which is a packed-refs file, into dir. + * + * A comment line of the form "# pack-refs with: " may contain zero or + * more traits. We interpret the traits as follows: + * + * No traits: + * + * Probably no references are peeled. But if the file contains a + * peeled value for a reference, we will use it. + * + * peeled: + * + * References under "refs/tags/", if they *can* be peeled, *are* + * peeled in this file. References outside of "refs/tags/" are + * probably not peeled even if they could have been, but if we find + * a peeled value for such a reference we will use it. + * + * fully-peeled: + * + * All references in the file that can be peeled are peeled. + * Inversely (and this is more important), any references in the + * file for which no peeled value is recorded is not peelable. This + * trait should typically be written alongside "peeled" for + * compatibility with older clients, but we do not require it + * (i.e., "peeled" is a no-op if "fully-peeled" is set). + */ static void read_packed_refs(FILE *f, struct ref_dir *dir) { struct ref_entry *last = NULL; char refline[PATH_MAX]; - int flag = REF_ISPACKED; + enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled = PEELED_NONE; while (fgets(refline, sizeof(refline), f)) { unsigned char sha1[20]; @@ -817,15 +844,20 @@ static void read_packed_refs(FILE *f, struct ref_dir *dir) if (!strncmp(refline, header, sizeof(header)-1)) { const char *traits = refline + sizeof(header) - 1; - if (strstr(traits, " peeled ")) - flag |= REF_KNOWS_PEELED; + if (strstr(traits, " fully-peeled ")) + peeled = PEELED_FULLY; + else if (strstr(traits, " peeled ")) + peeled = PEELED_TAGS; /* perhaps other traits later as well */ continue; } refname = parse_ref_line(refline, sha1); if (refname) { - last = create_ref_entry(refname, sha1, flag, 1); + last = create_ref_entry(refname, sha1, REF_ISPACKED, 1); + if (peeled == PEELED_FULLY || + (peeled == PEELED_TAGS && !prefixcmp(refname, "refs/tags/"))) + last->flag |= REF_KNOWS_PEELED; add_ref(dir, last); continue; } @@ -833,8 +865,15 @@ static void read_packed_refs(FILE *f, struct ref_dir *dir) refline[0] == '^' && strlen(refline) == 42 && refline[41] == '\n' && - !get_sha1_hex(refline + 1, sha1)) + !get_sha1_hex(refline + 1, sha1)) { hashcpy(last->u.value.peeled, sha1); + /* + * Regardless of what the file header said, + * we definitely know the value of *this* + * reference: + */ + last->flag |= REF_KNOWS_PEELED; + } } } |