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>

1 files changed, 16 insertions, 1 deletions

diff --git a/cache.h b/cache.h
index 985caced24..11d2482e30 100644
--- a/cache.h
+++ b/cache.h
@@ -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);