refs: implement removal of ref storages

We're about to introduce logic to migrate ref storages. One part of the
migration will be to delete the files that are part of the old ref
storage format. We don't yet have a way to delete such data generically
across ref backends though.

Implement a new `delete` callback and expose it via a new
`ref_storage_delete()` function.

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

1 files changed, 62 insertions, 0 deletions

diff --git a/refs/files-backend.c b/refs/files-backend.c
index de8cc83174..e663781199 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -3342,11 +3342,73 @@ static int files_ref_store_create_on_disk(struct ref_store *ref_store,
 	return 0;
 }
 
+struct remove_one_root_ref_data {
+	const char *gitdir;
+	struct strbuf *err;
+};
+
+static int remove_one_root_ref(const char *refname,
+			       void *cb_data)
+{
+	struct remove_one_root_ref_data *data = cb_data;
+	struct strbuf buf = STRBUF_INIT;
+	int ret = 0;
+
+	strbuf_addf(&buf, "%s/%s", data->gitdir, refname);
+
+	ret = unlink(buf.buf);
+	if (ret < 0)
+		strbuf_addf(data->err, "could not delete %s: %s\n",
+			    refname, strerror(errno));
+
+	strbuf_release(&buf);
+	return ret;
+}
+
+static int files_ref_store_remove_on_disk(struct ref_store *ref_store,
+					  struct strbuf *err)
+{
+	struct files_ref_store *refs =
+		files_downcast(ref_store, REF_STORE_WRITE, "remove");
+	struct remove_one_root_ref_data data = {
+		.gitdir = refs->base.gitdir,
+		.err = err,
+	};
+	struct strbuf sb = STRBUF_INIT;
+	int ret = 0;
+
+	strbuf_addf(&sb, "%s/refs", refs->base.gitdir);
+	if (remove_dir_recursively(&sb, 0) < 0) {
+		strbuf_addf(err, "could not delete refs: %s",
+			    strerror(errno));
+		ret = -1;
+	}
+	strbuf_reset(&sb);
+
+	strbuf_addf(&sb, "%s/logs", refs->base.gitdir);
+	if (remove_dir_recursively(&sb, 0) < 0) {
+		strbuf_addf(err, "could not delete logs: %s",
+			    strerror(errno));
+		ret = -1;
+	}
+	strbuf_reset(&sb);
+
+	if (for_each_root_ref(refs, remove_one_root_ref, &data) < 0)
+		ret = -1;
+
+	if (ref_store_remove_on_disk(refs->packed_ref_store, err) < 0)
+		ret = -1;
+
+	strbuf_release(&sb);
+	return ret;
+}
+
 struct ref_storage_be refs_be_files = {
 	.name = "files",
 	.init = files_ref_store_init,
 	.release = files_ref_store_release,
 	.create_on_disk = files_ref_store_create_on_disk,
+	.remove_on_disk = files_ref_store_remove_on_disk,
 
 	.transaction_prepare = files_transaction_prepare,
 	.transaction_finish = files_transaction_finish,