sha1_file: teach sha1_object_info_extended more flags

Improve sha1_object_info_extended() by supporting additional
flags. This allows has_sha1_file_with_flags() to be modified to use
sha1_object_info_extended() in a subsequent patch.

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

cache.h

@@ -1863,6 +1863,10 @@ struct object_info {
 #define OBJECT_INFO_LOOKUP_REPLACE 1
 /* Allow reading from a loose object file of unknown/bogus type */
 #define OBJECT_INFO_ALLOW_UNKNOWN_TYPE 2
+/* Do not check cached storage */
+#define OBJECT_INFO_SKIP_CACHED 4
+/* Do not retry packed storage after checking packed and loose storage */
+#define OBJECT_INFO_QUICK 8
 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

@@ -2977,14 +2977,14 @@ static int sha1_loose_object_info(const unsigned char *sha1,
 
 int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
 {
-	struct cached_object *co;
 	struct pack_entry e;
 	int rtype;
 	const unsigned char *real = (flags & OBJECT_INFO_LOOKUP_REPLACE) ?
 				    lookup_replace_object(sha1) :
 				    sha1;
 
-	co = find_cached_object(real);
+	if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
+		struct cached_object *co = find_cached_object(real);
 		if (co) {
 			if (oi->typep)
 				*(oi->typep) = co->type;
@@ -3001,6 +3001,7 @@ int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi,
 			oi->whence = OI_CACHED;
 			return 0;
 		}
+	}
 
 	if (!find_pack_entry(real, &e)) {
 		/* Most likely it's a loose object. */
@@ -3010,10 +3011,14 @@ int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi,
 		}
 
 		/* Not a loose object; someone else may have just packed it. */
+		if (flags & OBJECT_INFO_QUICK) {
+			return -1;
+		} else {
 			reprepare_packed_git();
 			if (!find_pack_entry(real, &e))
 				return -1;
 		}
+	}
 
 	rtype = packed_object_info(e.p, e.offset, oi);
 	if (rtype < 0) {