refs: move object peeling into "object.c"

Peeling an object has nothing to do with refs, but we still have the
code in "refs.c". Move it over into "object.c", which is a more natural
place to put it.

Ideally, we'd also move `peel_iterated_oid()` over into "object.c". But
this function is tied to the refs interfaces because it uses a global
ref iterator variable to optimize peeling when the iterator already has
the peeled object ID readily available.

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

object.c

@@ -207,6 +207,27 @@ struct object *lookup_object_by_type(struct repository *r,
 	}
 }
 
+enum peel_status peel_object(const struct object_id *name, struct object_id *oid)
+{
+	struct object *o = lookup_unknown_object(the_repository, name);
+
+	if (o->type == OBJ_NONE) {
+		int type = oid_object_info(the_repository, name, NULL);
+		if (type < 0 || !object_as_type(o, type, 0))
+			return PEEL_INVALID;
+	}
+
+	if (o->type != OBJ_TAG)
+		return PEEL_NON_TAG;
+
+	o = deref_tag_noverify(o);
+	if (!o)
+		return PEEL_INVALID;
+
+	oidcpy(oid, &o->oid);
+	return PEEL_PEELED;
+}
+
 struct object *parse_object_buffer(struct repository *r, const struct object_id *oid, enum object_type type, unsigned long size, void *buffer, int *eaten_p)
 {
 	struct object *obj;

object.h

@@ -256,6 +256,40 @@ struct object *lookup_unknown_object(struct repository *r, const struct object_i
 struct object *lookup_object_by_type(struct repository *r, const struct object_id *oid,
 				     enum object_type type);
 
+enum peel_status {
+	/* object was peeled successfully: */
+	PEEL_PEELED = 0,
+
+	/*
+	 * object cannot be peeled because the named object (or an
+	 * object referred to by a tag in the peel chain), does not
+	 * exist.
+	 */
+	PEEL_INVALID = -1,
+
+	/* object cannot be peeled because it is not a tag: */
+	PEEL_NON_TAG = -2,
+
+	/* ref_entry contains no peeled value because it is a symref: */
+	PEEL_IS_SYMREF = -3,
+
+	/*
+	 * ref_entry cannot be peeled because it is broken (i.e., the
+	 * symbolic reference cannot even be resolved to an object
+	 * name):
+	 */
+	PEEL_BROKEN = -4
+};
+
+/*
+ * Peel the named object; i.e., if the object is a tag, resolve the
+ * tag recursively until a non-tag is found.  If successful, store the
+ * result to oid and return PEEL_PEELED.  If the object is not a tag
+ * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
+ * and leave oid unchanged.
+ */
+enum peel_status peel_object(const struct object_id *name, struct object_id *oid);
+
 struct object_list *object_list_insert(struct object *item,
 				       struct object_list **list_p);
 

refs.c

@@ -19,7 +19,6 @@
 #include "object-store-ll.h"
 #include "object.h"
 #include "path.h"
-#include "tag.h"
 #include "submodule.h"
 #include "worktree.h"
 #include "strvec.h"
@@ -425,27 +424,6 @@ static int for_each_filter_refs(const char *refname,
 	return filter->fn(refname, oid, flags, filter->cb_data);
 }
 
-enum peel_status peel_object(const struct object_id *name, struct object_id *oid)
-{
-	struct object *o = lookup_unknown_object(the_repository, name);
-
-	if (o->type == OBJ_NONE) {
-		int type = oid_object_info(the_repository, name, NULL);
-		if (type < 0 || !object_as_type(o, type, 0))
-			return PEEL_INVALID;
-	}
-
-	if (o->type != OBJ_TAG)
-		return PEEL_NON_TAG;
-
-	o = deref_tag_noverify(o);
-	if (!o)
-		return PEEL_INVALID;
-
-	oidcpy(oid, &o->oid);
-	return PEEL_PEELED;
-}
-
 struct warn_if_dangling_data {
 	struct ref_store *refs;
 	FILE *fp;

refs/refs-internal.h

@@ -69,40 +69,6 @@ int ref_resolves_to_object(const char *refname,
 			   const struct object_id *oid,
 			   unsigned int flags);
 
-enum peel_status {
-	/* object was peeled successfully: */
-	PEEL_PEELED = 0,
-
-	/*
-	 * object cannot be peeled because the named object (or an
-	 * object referred to by a tag in the peel chain), does not
-	 * exist.
-	 */
-	PEEL_INVALID = -1,
-
-	/* object cannot be peeled because it is not a tag: */
-	PEEL_NON_TAG = -2,
-
-	/* ref_entry contains no peeled value because it is a symref: */
-	PEEL_IS_SYMREF = -3,
-
-	/*
-	 * ref_entry cannot be peeled because it is broken (i.e., the
-	 * symbolic reference cannot even be resolved to an object
-	 * name):
-	 */
-	PEEL_BROKEN = -4
-};
-
-/*
- * Peel the named object; i.e., if the object is a tag, resolve the
- * tag recursively until a non-tag is found.  If successful, store the
- * result to oid and return PEEL_PEELED.  If the object is not a tag
- * or is not valid, return PEEL_NON_TAG or PEEL_INVALID, respectively,
- * and leave oid unchanged.
- */
-enum peel_status peel_object(const struct object_id *name, struct object_id *oid);
-
 /**
  * Information needed for a single ref update. Set new_oid to the new
  * value or to null_oid to delete the ref. To check the old value