refs: refactor logic to look up storage backends

In order to look up ref storage backends, we're currently using a linked
list of backends, where each backend is expected to set up its `next`
pointer to the next ref storage backend. This is kind of a weird setup
as backends need to be aware of other backends without much of a reason.

Refactor the code so that the array of backends is centrally defined in
"refs.c", where each backend is now identified by an integer constant.
Expose functions to translate from those integer constants to the name
and vice versa, which will be required by subsequent patches.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Patrick Steinhardt
2023-12-29 08:26:34 +01:00
committed by Junio C Hamano
parent 465a22b338
commit 0fcc285c5e
7 changed files with 31 additions and 13 deletions

34
refs.c
View File

@ -33,17 +33,33 @@
/*
* List of all available backends
*/
static struct ref_storage_be *refs_backends = &refs_be_files;
static const struct ref_storage_be *refs_backends[] = {
[REF_STORAGE_FORMAT_FILES] = &refs_be_files,
};
static struct ref_storage_be *find_ref_storage_backend(const char *name)
static const struct ref_storage_be *find_ref_storage_backend(unsigned int ref_storage_format)
{
struct ref_storage_be *be;
for (be = refs_backends; be; be = be->next)
if (!strcmp(be->name, name))
return be;
if (ref_storage_format < ARRAY_SIZE(refs_backends))
return refs_backends[ref_storage_format];
return NULL;
}
unsigned int ref_storage_format_by_name(const char *name)
{
for (unsigned int i = 0; i < ARRAY_SIZE(refs_backends); i++)
if (refs_backends[i] && !strcmp(refs_backends[i]->name, name))
return i;
return REF_STORAGE_FORMAT_UNKNOWN;
}
const char *ref_storage_format_to_name(unsigned int ref_storage_format)
{
const struct ref_storage_be *be = find_ref_storage_backend(ref_storage_format);
if (!be)
return "unknown";
return be->name;
}
/*
* How to handle various characters in refnames:
* 0: An acceptable character for refs
@ -2029,12 +2045,12 @@ static struct ref_store *ref_store_init(struct repository *repo,
const char *gitdir,
unsigned int flags)
{
const char *be_name = "files";
struct ref_storage_be *be = find_ref_storage_backend(be_name);
unsigned int format = REF_STORAGE_FORMAT_FILES;
const struct ref_storage_be *be = find_ref_storage_backend(format);
struct ref_store *refs;
if (!be)
BUG("reference backend %s is unknown", be_name);
BUG("reference backend is unknown");
refs = be->init(repo, gitdir, flags);
return refs;