sha1_file: rename LOOKUP_UNKNOWN_OBJECT

The LOOKUP_UNKNOWN_OBJECT flag was introduced in commit 46f0344
("sha1_file: support reading from a loose object of unknown type",
2015-05-03) in order to support a feature in cat-file subsequently
introduced in commit 39e4ae3 ("cat-file: teach cat-file a
'--allow-unknown-type' option", 2015-05-03). Despite its name and
location in cache.h, this flag is used neither in
read_sha1_file_extended() nor in any of the lookup functions, but used
only in sha1_object_info_extended().

Therefore rename this flag to OBJECT_INFO_ALLOW_UNKNOWN_TYPE, taking the
name of the cat-file flag that invokes this feature, and move it closer
to the declaration of sha1_object_info_extended(). Also add
documentation for this flag.

OBJECT_INFO_ALLOW_UNKNOWN_TYPE is defined to 2, not 1, to avoid
conflicting with LOOKUP_REPLACE_OBJECT. Avoidance of this conflict is
necessary because sha1_object_info_extended() supports both flags.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/cat-file.c

@@ -60,7 +60,7 @@ static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
 	const char *path = force_path;
 
 	if (unknown_type)
-		flags |= LOOKUP_UNKNOWN_OBJECT;
+		flags |= OBJECT_INFO_ALLOW_UNKNOWN_TYPE;
 
 	if (get_sha1_with_context(obj_name, GET_SHA1_RECORD_PATH,
 				  oid.hash, &obj_context))

cache.h

@@ -1207,7 +1207,6 @@ extern char *xdg_cache_home(const char *filename);
 
 /* 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)
 {
@@ -1866,6 +1865,8 @@ struct object_info {
  */
 #define OBJECT_INFO_INIT {NULL}
 
+/* Allow reading from a loose object file of unknown/bogus type */
+#define OBJECT_INFO_ALLOW_UNKNOWN_TYPE 2
 extern int sha1_object_info_extended(const unsigned char *, struct object_info *, unsigned flags);
 extern int packed_object_info(struct packed_git *pack, off_t offset, struct object_info *);
 

sha1_file.c

@@ -1964,7 +1964,7 @@ static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
 	 * we're obtaining the type using '--allow-unknown-type'
 	 * option.
 	 */
-	if ((flags & LOOKUP_UNKNOWN_OBJECT) && (type < 0))
+	if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE) && (type < 0))
 		type = 0;
 	else if (type < 0)
 		die("invalid object type");
@@ -2941,7 +2941,7 @@ static int sha1_loose_object_info(const unsigned char *sha1,
 		return -1;
 	if (oi->disk_sizep)
 		*oi->disk_sizep = mapsize;
-	if ((flags & LOOKUP_UNKNOWN_OBJECT)) {
+	if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE)) {
 		if (unpack_sha1_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
 			status = error("unable to unpack %s header with --allow-unknown-type",
 				       sha1_to_hex(sha1));