object-file.c: simplify unpack_loose_short_header()

Combine the unpack_loose_short_header(),
unpack_loose_header_to_strbuf() and unpack_loose_header() functions
into one.

The unpack_loose_header_to_strbuf() function was added in
46f034483e (sha1_file: support reading from a loose object of unknown
type, 2015-05-03).

Its code was mostly copy/pasted between it and both of
unpack_loose_header() and unpack_loose_short_header(). We now have a
single unpack_loose_header() function which accepts an optional
"struct strbuf *" instead.

I think the remaining unpack_loose_header() function could be further
simplified, we're carrying some complexity just to be able to emit a
garbage type longer than MAX_HEADER_LEN, we could alternatively just
say "we found a garbage type <first 32 bytes>..." instead. But let's
leave the current behavior in place for now.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Ævar Arnfjörð Bjarmason 2021-10-01 11:16:48 +02:00 committed by Junio C Hamano
parent ddb3474b66
commit 01cab97679
3 changed files with 38 additions and 40 deletions

17
cache.h
View File

@ -1302,7 +1302,22 @@ char *xdg_cache_home(const char *filename);
int git_open_cloexec(const char *name, int flags);
#define git_open(name) git_open_cloexec(name, O_RDONLY)
int unpack_loose_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz);
/**
* unpack_loose_header() initializes the data stream needed to unpack
* a loose object header.
*
* Returns 0 on success. Returns negative values on error.
*
* It will only parse up to MAX_HEADER_LEN bytes unless an optional
* "hdrbuf" argument is non-NULL. This is intended for use with
* OBJECT_INFO_ALLOW_UNKNOWN_TYPE to extract the bad type for (error)
* reporting. The full header will be extracted to "hdrbuf" for use
* with parse_loose_header().
*/
int unpack_loose_header(git_zstream *stream, unsigned char *map,
unsigned long mapsize, void *buffer,
unsigned long bufsiz, struct strbuf *hdrbuf);
struct object_info;
int parse_loose_header(const char *hdr, struct object_info *oi,
unsigned int flags);

View File

@ -1210,11 +1210,12 @@ void *map_loose_object(struct repository *r,
return map_loose_object_1(r, NULL, oid, size);
}
static int unpack_loose_short_header(git_zstream *stream,
unsigned char *map, unsigned long mapsize,
void *buffer, unsigned long bufsiz)
int unpack_loose_header(git_zstream *stream,
unsigned char *map, unsigned long mapsize,
void *buffer, unsigned long bufsiz,
struct strbuf *header)
{
int ret;
int status;
/* Get the data stream */
memset(stream, 0, sizeof(*stream));
@ -1225,35 +1226,8 @@ static int unpack_loose_short_header(git_zstream *stream,
git_inflate_init(stream);
obj_read_unlock();
ret = git_inflate(stream, 0);
status = git_inflate(stream, 0);
obj_read_lock();
return ret;
}
int unpack_loose_header(git_zstream *stream,
unsigned char *map, unsigned long mapsize,
void *buffer, unsigned long bufsiz)
{
int status = unpack_loose_short_header(stream, map, mapsize,
buffer, bufsiz);
if (status < Z_OK)
return -1;
/* Make sure we have the terminating NUL */
if (!memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
return -1;
return 0;
}
static int unpack_loose_header_to_strbuf(git_zstream *stream, unsigned char *map,
unsigned long mapsize, void *buffer,
unsigned long bufsiz, struct strbuf *header)
{
int status;
status = unpack_loose_short_header(stream, map, mapsize, buffer, bufsiz);
if (status < Z_OK)
return -1;
@ -1263,6 +1237,14 @@ static int unpack_loose_header_to_strbuf(git_zstream *stream, unsigned char *map
if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
return 0;
/*
* We have a header longer than MAX_HEADER_LEN. The "header"
* here is only non-NULL when we run "cat-file
* --allow-unknown-type".
*/
if (!header)
return -1;
/*
* buffer[0..bufsiz] was not large enough. Copy the partial
* result out to header, and then append the result of further
@ -1412,6 +1394,7 @@ static int loose_object_info(struct repository *r,
char hdr[MAX_HEADER_LEN];
struct strbuf hdrbuf = STRBUF_INIT;
unsigned long size_scratch;
int allow_unknown = flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE;
if (oi->delta_base_oid)
oidclr(oi->delta_base_oid);
@ -1445,11 +1428,9 @@ static int loose_object_info(struct repository *r,
if (oi->disk_sizep)
*oi->disk_sizep = mapsize;
if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE)) {
if (unpack_loose_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
status = error(_("unable to unpack %s header with --allow-unknown-type"),
oid_to_hex(oid));
} else if (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
if (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr),
allow_unknown ? &hdrbuf : NULL) < 0)
status = error(_("unable to unpack %s header"),
oid_to_hex(oid));
if (status < 0)
@ -2550,7 +2531,8 @@ int read_loose_object(const char *path,
goto out;
}
if (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) {
if (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr),
NULL) < 0) {
error(_("unable to unpack header of %s"), path);
goto out;
}

View File

@ -233,7 +233,8 @@ static int open_istream_loose(struct git_istream *st, struct repository *r,
st->u.loose.mapped,
st->u.loose.mapsize,
st->u.loose.hdr,
sizeof(st->u.loose.hdr)) < 0) ||
sizeof(st->u.loose.hdr),
NULL) < 0) ||
(parse_loose_header(st->u.loose.hdr, &oi, 0) < 0)) {
git_inflate_end(&st->z);
munmap(st->u.loose.mapped, st->u.loose.mapsize);