1 files changed, 148 insertions, 119 deletions

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 6f9a631592..73380d7e99 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -89,9 +89,9 @@ static void clear_loose_ref_cache(struct files_ref_store *refs)
  * Create a new submodule ref cache and add it to the internal
  * set of caches.
  */
-static struct ref_store *files_ref_store_create(struct repository *repo,
-						const char *gitdir,
-						unsigned int flags)
+static struct ref_store *files_ref_store_init(struct repository *repo,
+					      const char *gitdir,
+					      unsigned int flags)
 {
 	struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
 	struct ref_store *ref_store = (struct ref_store *)refs;
@@ -102,7 +102,7 @@ static struct ref_store *files_ref_store_create(struct repository *repo,
 	get_common_dir_noenv(&sb, gitdir);
 	refs->gitcommondir = strbuf_detach(&sb, NULL);
 	refs->packed_ref_store =
-		packed_ref_store_create(repo, refs->gitcommondir, flags);
+		packed_ref_store_init(repo, refs->gitcommondir, flags);
 
 	chdir_notify_reparent("files-backend $GIT_DIR", &refs->base.gitdir);
 	chdir_notify_reparent("files-backend $GIT_COMMONDIR",
@@ -149,6 +149,14 @@ static struct files_ref_store *files_downcast(struct ref_store *ref_store,
 	return refs;
 }
 
+static void files_ref_store_release(struct ref_store *ref_store)
+{
+	struct files_ref_store *refs = files_downcast(ref_store, 0, "release");
+	free_ref_cache(refs->loose);
+	free(refs->gitcommondir);
+	ref_store_release(refs->packed_ref_store);
+}
+
 static void files_reflog_path(struct files_ref_store *refs,
 			      struct strbuf *sb,
 			      const char *refname)
@@ -1197,7 +1205,7 @@ static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
 	ref_transaction_add_update(
 			transaction, r->name,
 			REF_NO_DEREF | REF_HAVE_NEW | REF_HAVE_OLD | REF_IS_PRUNING,
-			null_oid(), &r->oid, NULL);
+			null_oid(), &r->oid, NULL, NULL, NULL);
 	if (ref_transaction_commit(transaction, &err))
 		goto cleanup;
 
@@ -1228,7 +1236,8 @@ static void prune_refs(struct files_ref_store *refs, struct ref_to_prune **refs_
 /*
  * Return true if the specified reference should be packed.
  */
-static int should_pack_ref(const char *refname,
+static int should_pack_ref(struct files_ref_store *refs,
+			   const char *refname,
 			   const struct object_id *oid, unsigned int ref_flags,
 			   struct pack_refs_opts *opts)
 {
@@ -1244,7 +1253,7 @@ static int should_pack_ref(const char *refname,
 		return 0;
 
 	/* Do not pack broken refs: */
-	if (!ref_resolves_to_object(refname, the_repository, oid, ref_flags))
+	if (!ref_resolves_to_object(refname, refs->base.repo, oid, ref_flags))
 		return 0;
 
 	if (ref_excluded(opts->exclusions, refname))
@@ -1276,14 +1285,14 @@ static int files_pack_refs(struct ref_store *ref_store,
 	packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR, &err);
 
 	iter = cache_ref_iterator_begin(get_loose_ref_cache(refs, 0), NULL,
-					the_repository, 0);
+					refs->base.repo, 0);
 	while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
 		/*
 		 * If the loose reference can be packed, add an entry
 		 * in the packed ref cache. If the reference should be
 		 * pruned, also add it to refs_to_prune.
 		 */
-		if (!should_pack_ref(iter->refname, iter->oid, iter->flags, opts))
+		if (!should_pack_ref(refs, iter->refname, iter->oid, iter->flags, opts))
 			continue;
 
 		/*
@@ -1291,7 +1300,7 @@ static int files_pack_refs(struct ref_store *ref_store,
 		 * packed-refs transaction:
 		 */
 		if (ref_transaction_update(transaction, iter->refname,
-					   iter->oid, NULL,
+					   iter->oid, NULL, NULL, NULL,
 					   REF_NO_DEREF, NULL, &err))
 			die("failure preparing to create packed reference %s: %s",
 			    iter->refname, err.buf);
@@ -1380,7 +1389,8 @@ static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
 	return ret;
 }
 
-static int write_ref_to_lockfile(struct ref_lock *lock,
+static int write_ref_to_lockfile(struct files_ref_store *refs,
+				 struct ref_lock *lock,
 				 const struct object_id *oid,
 				 int skip_oid_verification, struct strbuf *err);
 static int commit_ref_update(struct files_ref_store *refs,
@@ -1528,7 +1538,7 @@ static int files_copy_or_rename_ref(struct ref_store *ref_store,
 	}
 	oidcpy(&lock->old_oid, &orig_oid);
 
-	if (write_ref_to_lockfile(lock, &orig_oid, 0, &err) ||
+	if (write_ref_to_lockfile(refs, lock, &orig_oid, 0, &err) ||
 	    commit_ref_update(refs, lock, &orig_oid, logmsg, &err)) {
 		error("unable to write current sha1 into %s: %s", newrefname, err.buf);
 		strbuf_release(&err);
@@ -1548,7 +1558,7 @@ static int files_copy_or_rename_ref(struct ref_store *ref_store,
 
 	flag = log_all_ref_updates;
 	log_all_ref_updates = LOG_REFS_NONE;
-	if (write_ref_to_lockfile(lock, &orig_oid, 0, &err) ||
+	if (write_ref_to_lockfile(refs, lock, &orig_oid, 0, &err) ||
 	    commit_ref_update(refs, lock, &orig_oid, NULL, &err)) {
 		error("unable to write current sha1 into %s: %s", oldrefname, err.buf);
 		strbuf_release(&err);
@@ -1782,7 +1792,8 @@ static int files_log_ref_write(struct files_ref_store *refs,
  * Write oid into the open lockfile, then close the lockfile. On
  * errors, rollback the lockfile, fill in *err and return -1.
  */
-static int write_ref_to_lockfile(struct ref_lock *lock,
+static int write_ref_to_lockfile(struct files_ref_store *refs,
+				 struct ref_lock *lock,
 				 const struct object_id *oid,
 				 int skip_oid_verification, struct strbuf *err)
 {
@@ -1791,7 +1802,7 @@ static int write_ref_to_lockfile(struct ref_lock *lock,
 	int fd;
 
 	if (!skip_oid_verification) {
-		o = parse_object(the_repository, oid);
+		o = parse_object(refs->base.repo, oid);
 		if (!o) {
 			strbuf_addf(
 				err,
@@ -1810,7 +1821,7 @@ static int write_ref_to_lockfile(struct ref_lock *lock,
 		}
 	}
 	fd = get_lock_file_fd(&lock->lk);
-	if (write_in_full(fd, oid_to_hex(oid), the_hash_algo->hexsz) < 0 ||
+	if (write_in_full(fd, oid_to_hex(oid), refs->base.repo->hash_algo->hexsz) < 0 ||
 	    write_in_full(fd, &term, 1) < 0 ||
 	    fsync_component(FSYNC_COMPONENT_REFERENCE, get_lock_file_fd(&lock->lk)) < 0 ||
 	    close_ref_gently(lock) < 0) {
@@ -1902,66 +1913,23 @@ static int create_ref_symlink(struct ref_lock *lock, const char *target)
 	return ret;
 }
 
-static void update_symref_reflog(struct files_ref_store *refs,
-				 struct ref_lock *lock, const char *refname,
-				 const char *target, const char *logmsg)
-{
-	struct strbuf err = STRBUF_INIT;
-	struct object_id new_oid;
-
-	if (logmsg &&
-	    refs_resolve_ref_unsafe(&refs->base, target,
-				    RESOLVE_REF_READING, &new_oid, NULL) &&
-	    files_log_ref_write(refs, refname, &lock->old_oid,
-				&new_oid, logmsg, 0, &err)) {
-		error("%s", err.buf);
-		strbuf_release(&err);
-	}
-}
-
-static int create_symref_locked(struct files_ref_store *refs,
-				struct ref_lock *lock, const char *refname,
-				const char *target, const char *logmsg)
+static int create_symref_lock(struct files_ref_store *refs,
+			      struct ref_lock *lock, const char *refname,
+			      const char *target, struct strbuf *err)
 {
-	if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
-		update_symref_reflog(refs, lock, refname, target, logmsg);
-		return 0;
+	if (!fdopen_lock_file(&lock->lk, "w")) {
+		strbuf_addf(err, "unable to fdopen %s: %s",
+			     get_lock_file_path(&lock->lk), strerror(errno));
+		return -1;
 	}
 
-	if (!fdopen_lock_file(&lock->lk, "w"))
-		return error("unable to fdopen %s: %s",
+	if (fprintf(get_lock_file_fp(&lock->lk), "ref: %s\n", target) < 0) {
+		strbuf_addf(err, "unable to write to %s: %s",
 			     get_lock_file_path(&lock->lk), strerror(errno));
-
-	update_symref_reflog(refs, lock, refname, target, logmsg);
-
-	/* no error check; commit_ref will check ferror */
-	fprintf(get_lock_file_fp(&lock->lk), "ref: %s\n", target);
-	if (commit_ref(lock) < 0)
-		return error("unable to write symref for %s: %s", refname,
-			     strerror(errno));
-	return 0;
-}
-
-static int files_create_symref(struct ref_store *ref_store,
-			       const char *refname, const char *target,
-			       const char *logmsg)
-{
-	struct files_ref_store *refs =
-		files_downcast(ref_store, REF_STORE_WRITE, "create_symref");
-	struct strbuf err = STRBUF_INIT;
-	struct ref_lock *lock;
-	int ret;
-
-	lock = lock_ref_oid_basic(refs, refname, &err);
-	if (!lock) {
-		error("%s", err.buf);
-		strbuf_release(&err);
 		return -1;
 	}
 
-	ret = create_symref_locked(refs, lock, refname, target, logmsg);
-	unlock_ref(lock);
-	return ret;
+	return 0;
 }
 
 static int files_reflog_exists(struct ref_store *ref_store,
@@ -2308,7 +2276,7 @@ static int split_head_update(struct ref_update *update,
 			transaction, "HEAD",
 			update->flags | REF_LOG_ONLY | REF_NO_DEREF,
 			&update->new_oid, &update->old_oid,
-			update->msg);
+			NULL, NULL, update->msg);
 
 	/*
 	 * Add "HEAD". This insertion is O(N) in the transaction
@@ -2370,8 +2338,9 @@ static int split_symref_update(struct ref_update *update,
 
 	new_update = ref_transaction_add_update(
 			transaction, referent, new_flags,
-			&update->new_oid, &update->old_oid,
-			update->msg);
+			update->new_target ? NULL : &update->new_oid,
+			update->old_target ? NULL : &update->old_oid,
+			update->new_target, update->old_target, update->msg);
 
 	new_update->parent_update = update;
 
@@ -2400,17 +2369,6 @@ static int split_symref_update(struct ref_update *update,
 }
 
 /*
- * Return the refname under which update was originally requested.
- */
-static const char *original_update_refname(struct ref_update *update)
-{
-	while (update->parent_update)
-		update = update->parent_update;
-
-	return update->refname;
-}
-
-/*
  * Check whether the REF_HAVE_OLD and old_oid values stored in update
  * are consistent with oid, which is the reference's current value. If
  * everything is OK, return 0; otherwise, write an error message to
@@ -2426,16 +2384,16 @@ static int check_old_oid(struct ref_update *update, struct object_id *oid,
 	if (is_null_oid(&update->old_oid))
 		strbuf_addf(err, "cannot lock ref '%s': "
 			    "reference already exists",
-			    original_update_refname(update));
+			    ref_update_original_update_refname(update));
 	else if (is_null_oid(oid))
 		strbuf_addf(err, "cannot lock ref '%s': "
 			    "reference is missing but expected %s",
-			    original_update_refname(update),
+			    ref_update_original_update_refname(update),
 			    oid_to_hex(&update->old_oid));
 	else
 		strbuf_addf(err, "cannot lock ref '%s': "
 			    "is at %s but expected %s",
-			    original_update_refname(update),
+			    ref_update_original_update_refname(update),
 			    oid_to_hex(oid),
 			    oid_to_hex(&update->old_oid));
 
@@ -2470,7 +2428,7 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 
 	files_assert_main_repository(refs, "lock_ref_for_update");
 
-	if ((update->flags & REF_HAVE_NEW) && is_null_oid(&update->new_oid))
+	if ((update->flags & REF_HAVE_NEW) && ref_update_has_null_new_value(update))
 		update->flags |= REF_DELETING;
 
 	if (head_ref) {
@@ -2489,7 +2447,7 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 
 		reason = strbuf_detach(err, NULL);
 		strbuf_addf(err, "cannot lock ref '%s': %s",
-			    original_update_refname(update), reason);
+			    ref_update_original_update_refname(update), reason);
 		free(reason);
 		goto out;
 	}
@@ -2509,11 +2467,18 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 				if (update->flags & REF_HAVE_OLD) {
 					strbuf_addf(err, "cannot lock ref '%s': "
 						    "error reading reference",
-						    original_update_refname(update));
+						    ref_update_original_update_refname(update));
 					ret = TRANSACTION_GENERIC_ERROR;
 					goto out;
 				}
-			} else if (check_old_oid(update, &lock->old_oid, err)) {
+			}
+
+			if (update->old_target) {
+				if (ref_update_check_old_target(referent.buf, update, err)) {
+					ret = TRANSACTION_GENERIC_ERROR;
+					goto out;
+				}
+			} else if  (check_old_oid(update, &lock->old_oid, err)) {
 				ret = TRANSACTION_GENERIC_ERROR;
 				goto out;
 			}
@@ -2534,7 +2499,17 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 	} else {
 		struct ref_update *parent_update;
 
-		if (check_old_oid(update, &lock->old_oid, err)) {
+		/*
+		 * Even if the ref is a regular ref, if `old_target` is set, we
+		 * check the referent value. Ideally `old_target` should only
+		 * be set for symrefs, but we're strict about its usage.
+		 */
+		if (update->old_target) {
+			if (ref_update_check_old_target(referent.buf, update, err)) {
+				ret = TRANSACTION_GENERIC_ERROR;
+				goto out;
+			}
+		} else if  (check_old_oid(update, &lock->old_oid, err)) {
 			ret = TRANSACTION_GENERIC_ERROR;
 			goto out;
 		}
@@ -2552,9 +2527,28 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 		}
 	}
 
-	if ((update->flags & REF_HAVE_NEW) &&
-	    !(update->flags & REF_DELETING) &&
-	    !(update->flags & REF_LOG_ONLY)) {
+	if (update->new_target && !(update->flags & REF_LOG_ONLY)) {
+		if (create_symref_lock(refs, lock, update->refname,
+				       update->new_target, err)) {
+			ret = TRANSACTION_GENERIC_ERROR;
+			goto out;
+		}
+
+		if (close_ref_gently(lock)) {
+			strbuf_addf(err, "couldn't close '%s.lock'",
+				    update->refname);
+			ret = TRANSACTION_GENERIC_ERROR;
+			goto out;
+		}
+
+		/*
+		 * Once we have created the symref lock, the commit
+		 * phase of the transaction only needs to commit the lock.
+		 */
+		update->flags |= REF_NEEDS_COMMIT;
+	} else if ((update->flags & REF_HAVE_NEW) &&
+		   !(update->flags & REF_DELETING) &&
+		   !(update->flags & REF_LOG_ONLY)) {
 		if (!(update->type & REF_ISSYMREF) &&
 		    oideq(&lock->old_oid, &update->new_oid)) {
 			/*
@@ -2562,7 +2556,7 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 			 * value, so we don't need to write it.
 			 */
 		} else if (write_ref_to_lockfile(
-				   lock, &update->new_oid,
+				   refs, lock, &update->new_oid,
 				   update->flags & REF_SKIP_OID_VERIFICATION,
 				   err)) {
 			char *write_err = strbuf_detach(err, NULL);
@@ -2762,7 +2756,7 @@ static int files_transaction_prepare(struct ref_store *ref_store,
 					packed_transaction, update->refname,
 					REF_HAVE_NEW | REF_NO_DEREF,
 					&update->new_oid, NULL,
-					NULL);
+					NULL, NULL, NULL);
 		}
 	}
 
@@ -2817,6 +2811,43 @@ cleanup:
 	return ret;
 }
 
+static int parse_and_write_reflog(struct files_ref_store *refs,
+				  struct ref_update *update,
+				  struct ref_lock *lock,
+				  struct strbuf *err)
+{
+	if (update->new_target) {
+		/*
+		 * We want to get the resolved OID for the target, to ensure
+		 * that the correct value is added to the reflog.
+		 */
+		if (!refs_resolve_ref_unsafe(&refs->base, update->new_target,
+					     RESOLVE_REF_READING,
+					     &update->new_oid, NULL)) {
+			/*
+			 * TODO: currently we skip creating reflogs for dangling
+			 * symref updates. It would be nice to capture this as
+			 * zero oid updates however.
+			 */
+			return 0;
+		}
+	}
+
+	if (files_log_ref_write(refs, lock->ref_name, &lock->old_oid,
+				&update->new_oid, update->msg, update->flags, err)) {
+		char *old_msg = strbuf_detach(err, NULL);
+
+		strbuf_addf(err, "cannot update the ref '%s': %s",
+			    lock->ref_name, old_msg);
+		free(old_msg);
+		unlock_ref(lock);
+		update->backend_data = NULL;
+		return -1;
+	}
+
+	return 0;
+}
+
 static int files_transaction_finish(struct ref_store *ref_store,
 				    struct ref_transaction *transaction,
 				    struct strbuf *err)
@@ -2847,23 +2878,20 @@ static int files_transaction_finish(struct ref_store *ref_store,
 
 		if (update->flags & REF_NEEDS_COMMIT ||
 		    update->flags & REF_LOG_ONLY) {
-			if (files_log_ref_write(refs,
-						lock->ref_name,
-						&lock->old_oid,
-						&update->new_oid,
-						update->msg, update->flags,
-						err)) {
-				char *old_msg = strbuf_detach(err, NULL);
-
-				strbuf_addf(err, "cannot update the ref '%s': %s",
-					    lock->ref_name, old_msg);
-				free(old_msg);
-				unlock_ref(lock);
-				update->backend_data = NULL;
+			if (parse_and_write_reflog(refs, update, lock, err)) {
 				ret = TRANSACTION_GENERIC_ERROR;
 				goto cleanup;
 			}
 		}
+
+		/*
+		 * We try creating a symlink, if that succeeds we continue to the
+		 * next update. If not, we try and create a regular symref.
+		 */
+		if (update->new_target && prefer_symlink_refs)
+			if (!create_ref_symlink(lock, update->new_target))
+				continue;
+
 		if (update->flags & REF_NEEDS_COMMIT) {
 			clear_loose_ref_cache(refs);
 			if (commit_ref(lock)) {
@@ -3047,7 +3075,7 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
 		ref_transaction_add_update(packed_transaction, update->refname,
 					   update->flags & ~REF_HAVE_OLD,
 					   &update->new_oid, &update->old_oid,
-					   NULL);
+					   NULL, NULL, NULL);
 	}
 
 	if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
@@ -3211,7 +3239,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 			rollback_lock_file(&reflog_lock);
 		} else if (update &&
 			   (write_in_full(get_lock_file_fd(&lock->lk),
-				oid_to_hex(&cb.last_kept_oid), the_hash_algo->hexsz) < 0 ||
+				oid_to_hex(&cb.last_kept_oid), refs->base.repo->hash_algo->hexsz) < 0 ||
 			    write_str_in_full(get_lock_file_fd(&lock->lk), "\n") < 0 ||
 			    close_ref_gently(lock) < 0)) {
 			status |= error("couldn't write %s",
@@ -3235,12 +3263,12 @@ static int files_reflog_expire(struct ref_store *ref_store,
 	return -1;
 }
 
-static int files_init_db(struct ref_store *ref_store,
-			 int flags,
-			 struct strbuf *err UNUSED)
+static int files_ref_store_create_on_disk(struct ref_store *ref_store,
+					  int flags,
+					  struct strbuf *err UNUSED)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, REF_STORE_WRITE, "init_db");
+		files_downcast(ref_store, REF_STORE_WRITE, "create");
 	struct strbuf sb = STRBUF_INIT;
 
 	/*
@@ -3263,7 +3291,7 @@ static int files_init_db(struct ref_store *ref_store,
 	 * There is no need to create directories for common refs when creating
 	 * a worktree ref store.
 	 */
-	if (!(flags & REFS_INIT_DB_IS_WORKTREE)) {
+	if (!(flags & REF_STORE_CREATE_ON_DISK_IS_WORKTREE)) {
 		/*
 		 * Create .git/refs/{heads,tags}
 		 */
@@ -3282,15 +3310,16 @@ static int files_init_db(struct ref_store *ref_store,
 
 struct ref_storage_be refs_be_files = {
 	.name = "files",
-	.init = files_ref_store_create,
-	.init_db = files_init_db,
+	.init = files_ref_store_init,
+	.release = files_ref_store_release,
+	.create_on_disk = files_ref_store_create_on_disk,
+
 	.transaction_prepare = files_transaction_prepare,
 	.transaction_finish = files_transaction_finish,
 	.transaction_abort = files_transaction_abort,
 	.initial_transaction_commit = files_initial_transaction_commit,
 
 	.pack_refs = files_pack_refs,
-	.create_symref = files_create_symref,
 	.rename_ref = files_rename_ref,
 	.copy_ref = files_copy_ref,