refs: introduce ref_store_init_options

Reference backends are initiated via the `init()` function. When
initiating the function, the backend is also provided flags which denote
the access levels of the initiator. Create a new structure
`ref_store_init_options` to house such options and move the access flags
to this structure.

This allows easier extension of providing further options to the
backends. In the following commit, we'll also provide config around
reflog creation to the backends via the same structure.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

refs.c

@@ -2295,6 +2295,9 @@ static struct ref_store *ref_store_init(struct repository *repo,
 {
 	const struct ref_storage_be *be;
 	struct ref_store *refs;
+	struct ref_store_init_options opts = {
+		.access_flags = flags,
+	};
 
 	be = find_ref_storage_backend(format);
 	if (!be)
@@ -2304,7 +2307,8 @@ static struct ref_store *ref_store_init(struct repository *repo,
 	 * TODO Send in a 'struct worktree' instead of a 'gitdir', and
 	 * allow the backend to handle how it wants to deal with worktrees.
 	 */
-	refs = be->init(repo, repo->ref_storage_payload, gitdir, flags);
+	refs = be->init(repo, repo->ref_storage_payload, gitdir, &opts);
+
 	return refs;
 }
 

refs/files-backend.c

@@ -108,7 +108,7 @@ static void clear_loose_ref_cache(struct files_ref_store *refs)
 static struct ref_store *files_ref_store_init(struct repository *repo,
 					      const char *payload,
 					      const char *gitdir,
-					      unsigned int flags)
+					      const struct ref_store_init_options *opts)
 {
 	struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
 	struct ref_store *ref_store = (struct ref_store *)refs;
@@ -120,11 +120,13 @@ static struct ref_store *files_ref_store_init(struct repository *repo,
 					 &ref_common_dir);
 
 	base_ref_store_init(ref_store, repo, refdir.buf, &refs_be_files);
-	refs->store_flags = flags;
+
 	refs->gitcommondir = strbuf_detach(&ref_common_dir, NULL);
 	refs->packed_ref_store =
-		packed_ref_store_init(repo, NULL, refs->gitcommondir, flags);
+		packed_ref_store_init(repo, NULL, refs->gitcommondir, opts);
+	refs->store_flags = opts->access_flags;
 	refs->log_all_ref_updates = repo_settings_get_log_all_ref_updates(repo);
+
 	repo_config_get_bool(repo, "core.prefersymlinkrefs", &refs->prefer_symlink_refs);
 
 	chdir_notify_reparent("files-backend $GIT_DIR", &refs->base.gitdir);

refs/packed-backend.c

@@ -218,14 +218,14 @@ static size_t snapshot_hexsz(const struct snapshot *snapshot)
 struct ref_store *packed_ref_store_init(struct repository *repo,
 					const char *payload UNUSED,
 					const char *gitdir,
-					unsigned int store_flags)
+					const struct ref_store_init_options *opts)
 {
 	struct packed_ref_store *refs = xcalloc(1, sizeof(*refs));
 	struct ref_store *ref_store = (struct ref_store *)refs;
 	struct strbuf sb = STRBUF_INIT;
 
 	base_ref_store_init(ref_store, repo, gitdir, &refs_be_packed);
-	refs->store_flags = store_flags;
+	refs->store_flags = opts->access_flags;
 
 	strbuf_addf(&sb, "%s/packed-refs", gitdir);
 	refs->path = strbuf_detach(&sb, NULL);

refs/packed-backend.h

@@ -3,6 +3,7 @@
 
 struct repository;
 struct ref_transaction;
+struct ref_store_init_options;
 
 /*
  * Support for storing references in a `packed-refs` file.
@@ -16,7 +17,7 @@ struct ref_transaction;
 struct ref_store *packed_ref_store_init(struct repository *repo,
 					const char *payload,
 					const char *gitdir,
-					unsigned int store_flags);
+					const struct ref_store_init_options *options);
 
 /*
  * Lock the packed-refs file for writing. Flags is passed to

refs/refs-internal.h

@@ -385,6 +385,15 @@ struct ref_store;
 				 REF_STORE_ODB | \
 				 REF_STORE_MAIN)
 
+/*
+ * Options for initializing the ref backend. All backend-agnostic information
+ * which backends required will be held here.
+ */
+struct ref_store_init_options {
+	/* The kind of operations that the ref_store is allowed to perform. */
+	unsigned int access_flags;
+};
+
 /*
  * Initialize the ref_store for the specified gitdir. These functions
  * should call base_ref_store_init() to initialize the shared part of
@@ -393,7 +402,7 @@ struct ref_store;
 typedef struct ref_store *ref_store_init_fn(struct repository *repo,
 					    const char *payload,
 					    const char *gitdir,
-					    unsigned int flags);
+					    const struct ref_store_init_options *opts);
 /*
  * Release all memory and resources associated with the ref store.
  */

refs/reftable-backend.c

@@ -369,7 +369,7 @@ static int reftable_be_config(const char *var, const char *value,
 static struct ref_store *reftable_be_init(struct repository *repo,
 					  const char *payload,
 					  const char *gitdir,
-					  unsigned int store_flags)
+					  const struct ref_store_init_options *opts)
 {
 	struct reftable_ref_store *refs = xcalloc(1, sizeof(*refs));
 	struct strbuf ref_common_dir = STRBUF_INIT;
@@ -386,8 +386,8 @@ static struct ref_store *reftable_be_init(struct repository *repo,
 
 	base_ref_store_init(&refs->base, repo, refdir.buf, &refs_be_reftable);
 	strmap_init(&refs->worktree_backends);
-	refs->store_flags = store_flags;
 	refs->log_all_ref_updates = repo_settings_get_log_all_ref_updates(repo);
+	refs->store_flags = opts->access_flags;
 
 	switch (repo->hash_algo->format_id) {
 	case GIT_SHA1_FORMAT_ID: