files_pack_refs(): use a reference transaction to write packed refs

Now that the packed reference store supports transactions, we can use
a transaction to write the packed versions of references that we want
to pack. This decreases the coupling between `files_ref_store` and
`packed_ref_store`.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/refs/files-backend.c b/refs/files-backend.c
index 2c78f63..3475c6f 100644 (file)
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1100,6 +1100,11 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
        int ok;
        struct ref_to_prune *refs_to_prune = NULL;
        struct strbuf err = STRBUF_INIT;
+       struct ref_transaction *transaction;
+
+       transaction = ref_store_transaction_begin(refs->packed_ref_store, &err);
+       if (!transaction)
+               return -1;
 
        packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR, &err);
 
@@ -1115,12 +1120,14 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
                        continue;
 
                /*
-                * Create an entry in the packed-refs cache equivalent
-                * to the one from the loose ref cache, except that
-                * we don't copy the peeled status, because we want it
-                * to be re-peeled.
+                * Add a reference creation for this reference to the
+                * packed-refs transaction:
                 */
-               add_packed_ref(refs->packed_ref_store, iter->refname, iter->oid);
+               if (ref_transaction_update(transaction, iter->refname,
+                                          iter->oid->hash, NULL,
+                                          REF_NODEREF, NULL, &err))
+                       die("failure preparing to create packed reference %s: %s",
+                           iter->refname, err.buf);
 
                /* Schedule the loose reference for pruning if requested. */
                if ((flags & PACK_REFS_PRUNE)) {
@@ -1134,8 +1141,11 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
        if (ok != ITER_DONE)
                die("error while iterating over references");
 
-       if (commit_packed_refs(refs->packed_ref_store, &err))
-               die("unable to overwrite old ref-pack file: %s", err.buf);
+       if (ref_transaction_commit(transaction, &err))
+               die("unable to write new packed-refs: %s", err.buf);
+
+       ref_transaction_free(transaction);
+
        packed_refs_unlock(refs->packed_ref_store);
 
        prune_refs(refs, refs_to_prune);