object-file: get rid of `the_repository` in `has_loose_object()`

We implicitly depend on `the_repository` in `has_loose_object()`.
Refactor the function to accept an `odb_source` as input that should be
checked for such a loose object.

This refactoring changes semantics of the function to not check the
whole object database for such a loose object anymore, but instead we
now only check that single source. Existing callers thus need to loop
through all sources manually now.

While this change may seem illogical at first, whether or not an object
exists in a specific format should be answered by the source using that
format. As such, we can eventually convert this into a generic function
`odb_source_has_object()` that simply checks whether a given object
exists in an object source. And as we will know about the format that
any given source uses it allows us to derive whether the object exists
in a given format.

This change also makes `has_loose_object_nonlocal()` obsolete. The only
caller of this function is adapted so that it skips the primary object
source.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/pack-objects.c

@@ -1703,8 +1703,16 @@ static int want_object_in_pack_mtime(const struct object_id *oid,
 	struct list_head *pos;
 	struct multi_pack_index *m;
 
-	if (!exclude && local && has_loose_object_nonlocal(oid))
+	if (!exclude && local) {
+		/*
+		 * Note that we start iterating at `sources->next` so that we
+		 * skip the local object source.
+		 */
+		struct odb_source *source = the_repository->objects->sources->next;
+		for (; source; source = source->next)
+			if (has_loose_object(source, oid))
 				return 0;
+	}
 
 	/*
 	 * If we already know the pack object lives in, start checks from that
@@ -3928,7 +3936,14 @@ static void add_cruft_object_entry(const struct object_id *oid, enum object_type
 	} else {
 		if (!want_object_in_pack_mtime(oid, 0, &pack, &offset, mtime))
 			return;
-		if (!pack && type == OBJ_BLOB && !has_loose_object(oid)) {
+		if (!pack && type == OBJ_BLOB) {
+			struct odb_source *source = the_repository->objects->sources;
+			int found = 0;
+
+			for (; !found && source; source = source->next)
+				if (has_loose_object(source, oid))
+					found = 1;
+
 			/*
 			 * If a traversed tree has a missing blob then we want
 			 * to avoid adding that missing object to our pack.
@@ -3942,6 +3957,7 @@ static void add_cruft_object_entry(const struct object_id *oid, enum object_type
 			 * limited to "ensure non-tip blobs which don't exist in
 			 * packs do exist via loose objects". Confused?
 			 */
+			if (!found)
 				return;
 		}
 

object-file.c

@@ -121,14 +121,10 @@ static int check_and_freshen(const struct object_id *oid, int freshen)
 	       check_and_freshen_nonlocal(oid, freshen);
 }
 
-int has_loose_object_nonlocal(const struct object_id *oid)
+int has_loose_object(struct odb_source *source,
+		     const struct object_id *oid)
 {
-	return check_and_freshen_nonlocal(oid, 0);
-}
-
-int has_loose_object(const struct object_id *oid)
-{
-	return check_and_freshen(oid, 0);
+	return check_and_freshen_odb(source, oid, 0);
 }
 
 int format_object_header(char *str, size_t size, enum object_type type,
@@ -1103,8 +1099,10 @@ int force_object_loose(const struct object_id *oid, time_t mtime)
 	int hdrlen;
 	int ret;
 
-	if (has_loose_object(oid))
+	for (struct odb_source *source = repo->objects->sources; source; source = source->next)
+		if (has_loose_object(source, oid))
 			return 0;
+
 	oi.typep = &type;
 	oi.sizep = &len;
 	oi.contentp = &buf;

object-file.h

@@ -45,13 +45,12 @@ const char *odb_loose_path(struct odb_source *source,
 			   const struct object_id *oid);
 
 /*
- * Return true iff an alternate object database has a loose object
+ * Return true iff an object database source has a loose object
  * with the specified name.  This function does not respect replace
  * references.
  */
-int has_loose_object_nonlocal(const struct object_id *);
-
-int has_loose_object(const struct object_id *);
+int has_loose_object(struct odb_source *source,
+		     const struct object_id *oid);
 
 void *map_loose_object(struct repository *r, const struct object_id *oid,
 		       unsigned long *size);