sha1_file: support reading from a loose object of unknown type

Update sha1_loose_object_info() to optionally allow it to read
from a loose object file of unknown/bogus type; as the function
usually returns the type of the object it read in the form of enum
for known types, add an optional "typename" field to receive the
name of the type in textual form and a flag to indicate the reading
of a loose object file of unknown/bogus type.

Add parse_sha1_header_extended() which acts as a wrapper around
parse_sha1_header() allowing more information to be obtained.

Add unpack_sha1_header_to_strbuf() to unpack sha1 headers of
unknown/corrupt objects which have a unknown sha1 header size to
a strbuf structure. This was written by Junio C Hamano but tested
by me.

Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Helped-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Hepled-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/cache.h b/cache.h
index 3d3244ba64..38419c3a17 100644
--- a/cache.h
+++ b/cache.h
@@ -838,6 +838,7 @@ extern int is_ntfs_dotgit(const char *name);
 
 /* object replacement */
 #define LOOKUP_REPLACE_OBJECT 1
+#define LOOKUP_UNKNOWN_OBJECT 2
 extern void *read_sha1_file_extended(const unsigned char *sha1, enum object_type *type, unsigned long *size, unsigned flag);
 static inline void *read_sha1_file(const unsigned char *sha1, enum object_type *type, unsigned long *size)
 {
@@ -1304,6 +1305,7 @@ struct object_info {
 	unsigned long *sizep;
 	unsigned long *disk_sizep;
 	unsigned char *delta_base_sha1;
+	struct strbuf *typename;
 
 	/* Response */
 	enum {