sha1_file: rename LOOKUP_REPLACE_OBJECT

The LOOKUP_REPLACE_OBJECT flag controls whether the
lookup_replace_object() function is invoked by
sha1_object_info_extended(), read_sha1_file_extended(), and
lookup_replace_object_extended(), but it is not immediately clear which
functions accept that flag.

Therefore restrict this flag to only sha1_object_info_extended(),
renaming it appropriately to OBJECT_INFO_LOOKUP_REPLACE and adding some
documentation. Update read_sha1_file_extended() to have a boolean
parameter instead, and delete lookup_replace_object_extended().

parse_sha1_header() also passes this flag to
parse_sha1_header_extended() since commit 46f0344 ("sha1_file: support
reading from a loose object of unknown type", 2015-05-03), but that has
had no effect since that commit. Therefore this patch also removes this
flag from that invocation.

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

builtin/cat-file.c

@@ -56,7 +56,7 @@ static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
 	struct object_context obj_context;
 	struct object_info oi = OBJECT_INFO_INIT;
 	struct strbuf sb = STRBUF_INIT;
-	unsigned flags = LOOKUP_REPLACE_OBJECT;
+	unsigned flags = OBJECT_INFO_LOOKUP_REPLACE;
 	const char *path = force_path;
 
 	if (unknown_type)
@@ -337,7 +337,8 @@ static void batch_object_write(const char *obj_name, struct batch_options *opt,
 	struct strbuf buf = STRBUF_INIT;
 
 	if (!data->skip_object_info &&
-	    sha1_object_info_extended(data->oid.hash, &data->info, LOOKUP_REPLACE_OBJECT) < 0) {
+	    sha1_object_info_extended(data->oid.hash, &data->info,
+				      OBJECT_INFO_LOOKUP_REPLACE) < 0) {
 		printf("%s missing\n",
 		       obj_name ? obj_name : oid_to_hex(&data->oid));
 		fflush(stdout);

cache.h

@@ -1205,12 +1205,12 @@ extern char *xdg_config_home(const char *filename);
  */
 extern char *xdg_cache_home(const char *filename);
 
-/* object replacement */
+extern void *read_sha1_file_extended(const unsigned char *sha1,
-#define LOOKUP_REPLACE_OBJECT 1
+				     enum object_type *type,
-extern void *read_sha1_file_extended(const unsigned char *sha1, enum object_type *type, unsigned long *size, unsigned flag);
+				     unsigned long *size, int lookup_replace);
 static inline void *read_sha1_file(const unsigned char *sha1, enum object_type *type, unsigned long *size)
 {
-	return read_sha1_file_extended(sha1, type, size, LOOKUP_REPLACE_OBJECT);
+	return read_sha1_file_extended(sha1, type, size, 1);
 }
 
 /*
@@ -1232,13 +1232,6 @@ static inline const unsigned char *lookup_replace_object(const unsigned char *sh
 	return do_lookup_replace_object(sha1);
 }
 
-static inline const unsigned char *lookup_replace_object_extended(const unsigned char *sha1, unsigned flag)
-{
-	if (!(flag & LOOKUP_REPLACE_OBJECT))
-		return sha1;
-	return lookup_replace_object(sha1);
-}
-
 /* Read and unpack a sha1 file into memory, write memory to a sha1 file */
 extern int sha1_object_info(const unsigned char *, unsigned long *);
 extern int hash_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1);
@@ -1865,6 +1858,8 @@ struct object_info {
  */
 #define OBJECT_INFO_INIT {NULL}
 
+/* Invoke lookup_replace_object() on the given hash */
+#define OBJECT_INFO_LOOKUP_REPLACE 1
 /* 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);

sha1_file.c

@@ -2002,7 +2002,7 @@ int parse_sha1_header(const char *hdr, unsigned long *sizep)
 	struct object_info oi = OBJECT_INFO_INIT;
 
 	oi.sizep = sizep;
-	return parse_sha1_header_extended(hdr, &oi, LOOKUP_REPLACE_OBJECT);
+	return parse_sha1_header_extended(hdr, &oi, 0);
 }
 
 static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1)
@@ -2969,7 +2969,9 @@ int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi,
 	struct cached_object *co;
 	struct pack_entry e;
 	int rtype;
-	const unsigned char *real = lookup_replace_object_extended(sha1, flags);
+	const unsigned char *real = (flags & OBJECT_INFO_LOOKUP_REPLACE) ?
+				    lookup_replace_object(sha1) :
+				    sha1;
 
 	co = find_cached_object(real);
 	if (co) {
@@ -3025,7 +3027,8 @@ int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
 
 	oi.typep = &type;
 	oi.sizep = sizep;
-	if (sha1_object_info_extended(sha1, &oi, LOOKUP_REPLACE_OBJECT) < 0)
+	if (sha1_object_info_extended(sha1, &oi,
+				      OBJECT_INFO_LOOKUP_REPLACE) < 0)
 		return -1;
 	return type;
 }
@@ -3107,13 +3110,14 @@ static void *read_object(const unsigned char *sha1, enum object_type *type,
 void *read_sha1_file_extended(const unsigned char *sha1,
 			      enum object_type *type,
 			      unsigned long *size,
-			      unsigned flag)
+			      int lookup_replace)
 {
 	void *data;
 	const struct packed_git *p;
 	const char *path;
 	struct stat st;
-	const unsigned char *repl = lookup_replace_object_extended(sha1, flag);
+	const unsigned char *repl = lookup_replace ? lookup_replace_object(sha1)
+						   : sha1;
 
 	errno = 0;
 	data = read_object(repl, type, size);