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 46f034483eb (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>
Ævar Arnfjörð Bjarmason committed
Oct 1, 2021 at 11:16 UTC
01cab9767929c6c3faf4f4ad3b348639655f04fd
3 files changed
+38
-40
cache.h
+16
-1
@@ -1302,7 +1302,22 @@ char *xdg_cache_home(const char *filename);
1302
1303
int git_open_cloexec(const char *name, int flags);
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#define git_open(name) git_open_cloexec(name, O_RDONLY)
1305
-int unpack_loose_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz);
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+
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+/**
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+ * unpack_loose_header() initializes the data stream needed to unpack
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+ * a loose object header.
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+ *
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+ * Returns 0 on success. Returns negative values on error.
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+ *
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+ * It will only parse up to MAX_HEADER_LEN bytes unless an optional
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+ * "hdrbuf" argument is non-NULL. This is intended for use with
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+ * OBJECT_INFO_ALLOW_UNKNOWN_TYPE to extract the bad type for (error)
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+ * reporting. The full header will be extracted to "hdrbuf" for use
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+ * with parse_loose_header().
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+ */
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+int unpack_loose_header(git_zstream *stream, unsigned char *map,
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+ unsigned long mapsize, void *buffer,
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+ unsigned long bufsiz, struct strbuf *hdrbuf);
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struct object_info;
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int parse_loose_header(const char *hdr, struct object_info *oi,
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unsigned int flags);
object-file.c
+20
-38
@@ -1210,11 +1210,12 @@ void *map_loose_object(struct repository *r,
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return map_loose_object_1(r, NULL, oid, size);
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}
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-static int unpack_loose_short_header(git_zstream *stream,
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- unsigned char *map, unsigned long mapsize,
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- void *buffer, unsigned long bufsiz)
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+int unpack_loose_header(git_zstream *stream,
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+ unsigned char *map, unsigned long mapsize,
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+ void *buffer, unsigned long bufsiz,
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+ struct strbuf *header)
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{
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- int ret;
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+ int status;
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/* Get the data stream */
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memset(stream, 0, sizeof(*stream));
@@ -1225,35 +1226,8 @@ static int unpack_loose_short_header(git_zstream *stream,
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git_inflate_init(stream);
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obj_read_unlock();
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- ret = git_inflate(stream, 0);
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+ status = git_inflate(stream, 0);
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obj_read_lock();
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-
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- return ret;
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-}
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-
1234
-int unpack_loose_header(git_zstream *stream,
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- unsigned char *map, unsigned long mapsize,
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- void *buffer, unsigned long bufsiz)
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-{
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- int status = unpack_loose_short_header(stream, map, mapsize,
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- buffer, bufsiz);
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-
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- if (status < Z_OK)
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- return -1;
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-
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- /* Make sure we have the terminating NUL */
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- if (!memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
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- return -1;
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- return 0;
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-}
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-
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-static int unpack_loose_header_to_strbuf(git_zstream *stream, unsigned char *map,
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- unsigned long mapsize, void *buffer,
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- unsigned long bufsiz, struct strbuf *header)
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-{
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- int status;
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-
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- status = unpack_loose_short_header(stream, map, mapsize, buffer, bufsiz);
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if (status < Z_OK)
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return -1;
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@@ -1263,6 +1237,14 @@ static int unpack_loose_header_to_strbuf(git_zstream *stream, unsigned char *map
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if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
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return 0;
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+ /*
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+ * We have a header longer than MAX_HEADER_LEN. The "header"
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+ * here is only non-NULL when we run "cat-file
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+ * --allow-unknown-type".
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+ */
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+ if (!header)
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+ return -1;
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+
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/*
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* buffer[0..bufsiz] was not large enough. Copy the partial
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* result out to header, and then append the result of further
@@ -1412,6 +1394,7 @@ static int loose_object_info(struct repository *r,
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char hdr[MAX_HEADER_LEN];
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struct strbuf hdrbuf = STRBUF_INIT;
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unsigned long size_scratch;
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+ int allow_unknown = flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE;
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if (oi->delta_base_oid)
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oidclr(oi->delta_base_oid);
@@ -1445,11 +1428,9 @@ static int loose_object_info(struct repository *r,
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if (oi->disk_sizep)
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*oi->disk_sizep = mapsize;
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- if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE)) {
1449
- if (unpack_loose_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
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- status = error(_("unable to unpack %s header with --allow-unknown-type"),
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- oid_to_hex(oid));
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- } else if (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
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+
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+ if (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr),
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+ allow_unknown ? &hdrbuf : NULL) < 0)
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status = error(_("unable to unpack %s header"),
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oid_to_hex(oid));
1436
if (status < 0)
@@ -2550,7 +2531,8 @@ int read_loose_object(const char *path,
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goto out;
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}
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2553
- if (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) {
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+ if (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr),
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+ NULL) < 0) {
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error(_("unable to unpack header of %s"), path);
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goto out;
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}
streaming.c
+2
-1
@@ -233,7 +233,8 @@ static int open_istream_loose(struct git_istream *st, struct repository *r,
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st->u.loose.mapped,
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st->u.loose.mapsize,
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st->u.loose.hdr,
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- sizeof(st->u.loose.hdr)) < 0) ||
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+ sizeof(st->u.loose.hdr),
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+ NULL) < 0) ||
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(parse_loose_header(st->u.loose.hdr, &oi, 0) < 0)) {
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git_inflate_end(&st->z);
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munmap(st->u.loose.mapped, st->u.loose.mapsize);