refs/reftable: figure out hash via reftable_stack

The function `read_ref_without_reload()` accepts a ref store as input
only so that we can figure out the hash function used by it. This is
duplicate information though because the reftable stack knows about its
hash function, too.

Drop the superfluous parameter to simplify the calling convention a bit.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

refs/reftable-backend.c

@@ -243,8 +243,7 @@ static void fill_reftable_log_record(struct reftable_log_record *log, const stru
 	log->value.update.tz_offset = sign * atoi(tz_begin);
 }
 
-static int read_ref_without_reload(struct reftable_ref_store *refs,
-				   struct reftable_stack *stack,
+static int read_ref_without_reload(struct reftable_stack *stack,
 				   const char *refname,
 				   struct object_id *oid,
 				   struct strbuf *referent,
@@ -262,8 +261,21 @@ static int read_ref_without_reload(struct reftable_ref_store *refs,
 		strbuf_addstr(referent, ref.value.symref);
 		*type |= REF_ISSYMREF;
 	} else if (reftable_ref_record_val1(&ref)) {
+		unsigned int hash_id;
+
+		switch (reftable_stack_hash_id(stack)) {
+		case REFTABLE_HASH_SHA1:
+			hash_id = GIT_HASH_SHA1;
+			break;
+		case REFTABLE_HASH_SHA256:
+			hash_id = GIT_HASH_SHA256;
+			break;
+		default:
+			BUG("unhandled hash ID %d", reftable_stack_hash_id(stack));
+		}
+
 		oidread(oid, reftable_ref_record_val1(&ref),
-			refs->base.repo->hash_algo);
+			&hash_algos[hash_id]);
 	} else {
 		/* We got a tombstone, which should not happen. */
 		BUG("unhandled reference value type %d", ref.value_type);
@@ -855,7 +867,7 @@ static int reftable_be_read_raw_ref(struct ref_store *ref_store,
 	if (ret)
 		return ret;
 
-	ret = read_ref_without_reload(refs, be->stack, refname, oid, referent, type);
+	ret = read_ref_without_reload(be->stack, refname, oid, referent, type);
 	if (ret < 0)
 		return ret;
 	if (ret > 0) {
@@ -1091,7 +1103,7 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
 	if (ret)
 		goto done;
 
-	ret = read_ref_without_reload(refs, be->stack, "HEAD",
+	ret = read_ref_without_reload(be->stack, "HEAD",
 				      &head_oid, &head_referent, &head_type);
 	if (ret < 0)
 		goto done;
@@ -1167,7 +1179,7 @@ static int reftable_be_transaction_prepare(struct ref_store *ref_store,
 			string_list_insert(&affected_refnames, new_update->refname);
 		}
 
-		ret = read_ref_without_reload(refs, be->stack, rewritten_ref,
+		ret = read_ref_without_reload(be->stack, rewritten_ref,
 					      &current_oid, &referent, &u->type);
 		if (ret < 0)
 			goto done;
@@ -1733,7 +1745,7 @@ static int write_copy_table(struct reftable_writer *writer, void *cb_data)
 		memcpy(logs[logs_nr].value.update.old_hash, old_ref.value.val1, GIT_MAX_RAWSZ);
 		logs_nr++;
 
-		ret = read_ref_without_reload(arg->refs, arg->stack, "HEAD", &head_oid,
+		ret = read_ref_without_reload(arg->stack, "HEAD", &head_oid,
 					      &head_referent, &head_type);
 		if (ret < 0)
 			goto done;