packfile: inline custom read_object()

When the pack code was split into its own file[1], it got a copy of the
static read_object() function. But there's only one caller here, so we
could just inline it. And it's worth doing so, as the name read_object()
invites comparisons to the public read_object_file(), but the two don't
behave quite the same.

[1] The move happened over several commits, but the relevant one here is
    f1d8130 (pack: move clear_delta_base_cache(), packed_object_info(),
    unpack_entry(), 2017-08-18).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: peff

packfile.c

@@ -1650,22 +1650,6 @@ struct unpack_entry_stack_ent {
 	unsigned long size;
 };
 
-static void *read_object(struct repository *r,
-			 const struct object_id *oid,
-			 enum object_type *type,
-			 unsigned long *size)
-{
-	struct object_info oi = OBJECT_INFO_INIT;
-	void *content;
-	oi.typep = type;
-	oi.sizep = size;
-	oi.contentp = &content;
-
-	if (oid_object_info_extended(r, oid, &oi, 0) < 0)
-		return NULL;
-	return content;
-}
-
 void *unpack_entry(struct repository *r, struct packed_git *p, off_t obj_offset,
 		   enum object_type *final_type, unsigned long *final_size)
 {
@@ -1798,14 +1782,22 @@ void *unpack_entry(struct repository *r, struct packed_git *p, off_t obj_offset,
 			uint32_t pos;
 			struct object_id base_oid;
 			if (!(offset_to_pack_pos(p, obj_offset, &pos))) {
+				struct object_info oi = OBJECT_INFO_INIT;
+
 				nth_packed_object_id(&base_oid, p,
 						     pack_pos_to_index(p, pos));
 				error("failed to read delta base object %s"
 				      " at offset %"PRIuMAX" from %s",
 				      oid_to_hex(&base_oid), (uintmax_t)obj_offset,
 				      p->pack_name);
 				mark_bad_packed_object(p, &base_oid);
-				base = read_object(r, &base_oid, &type, &base_size);
+
+				oi.typep = &type;
+				oi.sizep = &base_size;
+				oi.contentp = &base;
+				if (oid_object_info_extended(r, &base_oid, &oi, 0) < 0)
+					base = NULL;
+
 				external_base = base;
 			}
 		}