ref_store: implement `refs_peel_ref()` generically
[gitweb.git] / refs / files-backend.c
index 3475c6f8a223515ebbfc5c091b93f5e44b82e251..7d12de88d015a73ce8cc77da5e01ad1a43086025 100644 (file)
@@ -655,43 +655,6 @@ static int lock_raw_ref(struct files_ref_store *refs,
        return ret;
 }
 
-static int files_peel_ref(struct ref_store *ref_store,
-                         const char *refname, unsigned char *sha1)
-{
-       struct files_ref_store *refs =
-               files_downcast(ref_store, REF_STORE_READ | REF_STORE_ODB,
-                              "peel_ref");
-       int flag;
-       unsigned char base[20];
-
-       if (current_ref_iter && current_ref_iter->refname == refname) {
-               struct object_id peeled;
-
-               if (ref_iterator_peel(current_ref_iter, &peeled))
-                       return -1;
-               hashcpy(sha1, peeled.hash);
-               return 0;
-       }
-
-       if (refs_read_ref_full(ref_store, refname,
-                              RESOLVE_REF_READING, base, &flag))
-               return -1;
-
-       /*
-        * If the reference is packed, read its ref_entry from the
-        * cache in the hope that we already know its peeled value.
-        * We only try this optimization on packed references because
-        * (a) forcing the filling of the loose reference cache could
-        * be expensive and (b) loose references anyway usually do not
-        * have REF_KNOWS_PEELED.
-        */
-       if (flag & REF_ISPACKED &&
-           !refs_peel_ref(refs->packed_ref_store, refname, sha1))
-               return 0;
-
-       return peel_object(base, sha1);
-}
-
 struct files_ref_iterator {
        struct ref_iterator base;
 
@@ -762,7 +725,7 @@ static struct ref_iterator *files_ref_iterator_begin(
                const char *prefix, unsigned int flags)
 {
        struct files_ref_store *refs;
-       struct ref_iterator *loose_iter, *packed_iter;
+       struct ref_iterator *loose_iter, *packed_iter, *overlay_iter;
        struct files_ref_iterator *iter;
        struct ref_iterator *ref_iterator;
        unsigned int required_flags = REF_STORE_READ;
@@ -772,10 +735,6 @@ static struct ref_iterator *files_ref_iterator_begin(
 
        refs = files_downcast(ref_store, required_flags, "ref_iterator_begin");
 
-       iter = xcalloc(1, sizeof(*iter));
-       ref_iterator = &iter->base;
-       base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
-
        /*
         * We must make sure that all loose refs are read before
         * accessing the packed-refs file; this avoids a race
@@ -811,7 +770,13 @@ static struct ref_iterator *files_ref_iterator_begin(
                        refs->packed_ref_store, prefix, 0,
                        DO_FOR_EACH_INCLUDE_BROKEN);
 
-       iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);
+       overlay_iter = overlay_ref_iterator_begin(loose_iter, packed_iter);
+
+       iter = xcalloc(1, sizeof(*iter));
+       ref_iterator = &iter->base;
+       base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable,
+                              overlay_iter->ordered);
+       iter->iter0 = overlay_iter;
        iter->flags = flags;
 
        return ref_iterator;
@@ -1057,11 +1022,17 @@ static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
        strbuf_release(&err);
 }
 
-static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r)
+/*
+ * Prune the loose versions of the references in the linked list
+ * `*refs_to_prune`, freeing the entries in the list as we go.
+ */
+static void prune_refs(struct files_ref_store *refs, struct ref_to_prune **refs_to_prune)
 {
-       while (r) {
+       while (*refs_to_prune) {
+               struct ref_to_prune *r = *refs_to_prune;
+               *refs_to_prune = r->next;
                prune_ref(refs, r);
-               r = r->next;
+               free(r);
        }
 }
 
@@ -1148,7 +1119,7 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
 
        packed_refs_unlock(refs->packed_ref_store);
 
-       prune_refs(refs, refs_to_prune);
+       prune_refs(refs, &refs_to_prune);
        strbuf_release(&err);
        return 0;
 }
@@ -2078,7 +2049,7 @@ static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_st
        struct ref_iterator *ref_iterator = &iter->base;
        struct strbuf sb = STRBUF_INIT;
 
-       base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
+       base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable, 0);
        files_reflog_path(refs, &sb, NULL);
        iter->dir_iterator = dir_iterator_begin(sb.buf);
        iter->ref_store = ref_store;
@@ -2391,13 +2362,22 @@ static int lock_ref_for_update(struct files_ref_store *refs,
        return 0;
 }
 
+struct files_transaction_backend_data {
+       struct ref_transaction *packed_transaction;
+       int packed_refs_locked;
+};
+
 /*
  * Unlock any references in `transaction` that are still locked, and
  * mark the transaction closed.
  */
-static void files_transaction_cleanup(struct ref_transaction *transaction)
+static void files_transaction_cleanup(struct files_ref_store *refs,
+                                     struct ref_transaction *transaction)
 {
        size_t i;
+       struct files_transaction_backend_data *backend_data =
+               transaction->backend_data;
+       struct strbuf err = STRBUF_INIT;
 
        for (i = 0; i < transaction->nr; i++) {
                struct ref_update *update = transaction->updates[i];
@@ -2409,6 +2389,17 @@ static void files_transaction_cleanup(struct ref_transaction *transaction)
                }
        }
 
+       if (backend_data->packed_transaction &&
+           ref_transaction_abort(backend_data->packed_transaction, &err)) {
+               error("error aborting transaction: %s", err.buf);
+               strbuf_release(&err);
+       }
+
+       if (backend_data->packed_refs_locked)
+               packed_refs_unlock(refs->packed_ref_store);
+
+       free(backend_data);
+
        transaction->state = REF_TRANSACTION_CLOSED;
 }
 
@@ -2425,12 +2416,17 @@ static int files_transaction_prepare(struct ref_store *ref_store,
        char *head_ref = NULL;
        int head_type;
        struct object_id head_oid;
+       struct files_transaction_backend_data *backend_data;
+       struct ref_transaction *packed_transaction = NULL;
 
        assert(err);
 
        if (!transaction->nr)
                goto cleanup;
 
+       backend_data = xcalloc(1, sizeof(*backend_data));
+       transaction->backend_data = backend_data;
+
        /*
         * Fail if a refname appears more than once in the
         * transaction. (If we end up splitting up any updates using
@@ -2497,6 +2493,41 @@ static int files_transaction_prepare(struct ref_store *ref_store,
                                          head_ref, &affected_refnames, err);
                if (ret)
                        break;
+
+               if (update->flags & REF_DELETING &&
+                   !(update->flags & REF_LOG_ONLY) &&
+                   !(update->flags & REF_ISPRUNING)) {
+                       /*
+                        * This reference has to be deleted from
+                        * packed-refs if it exists there.
+                        */
+                       if (!packed_transaction) {
+                               packed_transaction = ref_store_transaction_begin(
+                                               refs->packed_ref_store, err);
+                               if (!packed_transaction) {
+                                       ret = TRANSACTION_GENERIC_ERROR;
+                                       goto cleanup;
+                               }
+
+                               backend_data->packed_transaction =
+                                       packed_transaction;
+                       }
+
+                       ref_transaction_add_update(
+                                       packed_transaction, update->refname,
+                                       update->flags & ~REF_HAVE_OLD,
+                                       update->new_oid.hash, update->old_oid.hash,
+                                       NULL);
+               }
+       }
+
+       if (packed_transaction) {
+               if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
+                       ret = TRANSACTION_GENERIC_ERROR;
+                       goto cleanup;
+               }
+               backend_data->packed_refs_locked = 1;
+               ret = ref_transaction_prepare(packed_transaction, err);
        }
 
 cleanup:
@@ -2504,7 +2535,7 @@ static int files_transaction_prepare(struct ref_store *ref_store,
        string_list_clear(&affected_refnames, 0);
 
        if (ret)
-               files_transaction_cleanup(transaction);
+               files_transaction_cleanup(refs, transaction);
        else
                transaction->state = REF_TRANSACTION_PREPARED;
 
@@ -2519,9 +2550,10 @@ static int files_transaction_finish(struct ref_store *ref_store,
                files_downcast(ref_store, 0, "ref_transaction_finish");
        size_t i;
        int ret = 0;
-       struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
-       struct string_list_item *ref_to_delete;
        struct strbuf sb = STRBUF_INIT;
+       struct files_transaction_backend_data *backend_data;
+       struct ref_transaction *packed_transaction;
+
 
        assert(err);
 
@@ -2530,6 +2562,9 @@ static int files_transaction_finish(struct ref_store *ref_store,
                return 0;
        }
 
+       backend_data = transaction->backend_data;
+       packed_transaction = backend_data->packed_transaction;
+
        /* Perform updates first so live commits remain referenced */
        for (i = 0; i < transaction->nr; i++) {
                struct ref_update *update = transaction->updates[i];
@@ -2565,7 +2600,44 @@ static int files_transaction_finish(struct ref_store *ref_store,
                        }
                }
        }
-       /* Perform deletes now that updates are safely completed */
+
+       /*
+        * Now that updates are safely completed, we can perform
+        * deletes. First delete the reflogs of any references that
+        * will be deleted, since (in the unexpected event of an
+        * error) leaving a reference without a reflog is less bad
+        * than leaving a reflog without a reference (the latter is a
+        * mildly invalid repository state):
+        */
+       for (i = 0; i < transaction->nr; i++) {
+               struct ref_update *update = transaction->updates[i];
+               if (update->flags & REF_DELETING &&
+                   !(update->flags & REF_LOG_ONLY) &&
+                   !(update->flags & REF_ISPRUNING)) {
+                       strbuf_reset(&sb);
+                       files_reflog_path(refs, &sb, update->refname);
+                       if (!unlink_or_warn(sb.buf))
+                               try_remove_empty_parents(refs, update->refname,
+                                                        REMOVE_EMPTY_PARENTS_REFLOG);
+               }
+       }
+
+       /*
+        * Perform deletes now that updates are safely completed.
+        *
+        * First delete any packed versions of the references, while
+        * retaining the packed-refs lock:
+        */
+       if (packed_transaction) {
+               ret = ref_transaction_commit(packed_transaction, err);
+               ref_transaction_free(packed_transaction);
+               packed_transaction = NULL;
+               backend_data->packed_transaction = NULL;
+               if (ret)
+                       goto cleanup;
+       }
+
+       /* Now delete the loose versions of the references: */
        for (i = 0; i < transaction->nr; i++) {
                struct ref_update *update = transaction->updates[i];
                struct ref_lock *lock = update->backend_data;
@@ -2583,39 +2655,13 @@ static int files_transaction_finish(struct ref_store *ref_store,
                                }
                                update->flags |= REF_DELETED_LOOSE;
                        }
-
-                       if (!(update->flags & REF_ISPRUNING))
-                               string_list_append(&refs_to_delete,
-                                                  lock->ref_name);
                }
        }
 
-       if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
-               ret = TRANSACTION_GENERIC_ERROR;
-               goto cleanup;
-       }
-
-       if (repack_without_refs(refs->packed_ref_store, &refs_to_delete, err)) {
-               ret = TRANSACTION_GENERIC_ERROR;
-               packed_refs_unlock(refs->packed_ref_store);
-               goto cleanup;
-       }
-
-       packed_refs_unlock(refs->packed_ref_store);
-
-       /* Delete the reflogs of any references that were deleted: */
-       for_each_string_list_item(ref_to_delete, &refs_to_delete) {
-               strbuf_reset(&sb);
-               files_reflog_path(refs, &sb, ref_to_delete->string);
-               if (!unlink_or_warn(sb.buf))
-                       try_remove_empty_parents(refs, ref_to_delete->string,
-                                                REMOVE_EMPTY_PARENTS_REFLOG);
-       }
-
        clear_loose_ref_cache(refs);
 
 cleanup:
-       files_transaction_cleanup(transaction);
+       files_transaction_cleanup(refs, transaction);
 
        for (i = 0; i < transaction->nr; i++) {
                struct ref_update *update = transaction->updates[i];
@@ -2633,7 +2679,6 @@ static int files_transaction_finish(struct ref_store *ref_store,
        }
 
        strbuf_release(&sb);
-       string_list_clear(&refs_to_delete, 0);
        return ret;
 }
 
@@ -2641,7 +2686,10 @@ static int files_transaction_abort(struct ref_store *ref_store,
                                   struct ref_transaction *transaction,
                                   struct strbuf *err)
 {
-       files_transaction_cleanup(transaction);
+       struct files_ref_store *refs =
+               files_downcast(ref_store, 0, "ref_transaction_abort");
+
+       files_transaction_cleanup(refs, transaction);
        return 0;
 }
 
@@ -2663,6 +2711,7 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
        size_t i;
        int ret = 0;
        struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
+       struct ref_transaction *packed_transaction = NULL;
 
        assert(err);
 
@@ -2695,6 +2744,12 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
                                 &affected_refnames))
                die("BUG: initial ref transaction called with existing refs");
 
+       packed_transaction = ref_store_transaction_begin(refs->packed_ref_store, err);
+       if (!packed_transaction) {
+               ret = TRANSACTION_GENERIC_ERROR;
+               goto cleanup;
+       }
+
        for (i = 0; i < transaction->nr; i++) {
                struct ref_update *update = transaction->updates[i];
 
@@ -2707,6 +2762,15 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
                        ret = TRANSACTION_NAME_CONFLICT;
                        goto cleanup;
                }
+
+               /*
+                * Add a reference creation for this reference to the
+                * packed-refs transaction:
+                */
+               ref_transaction_add_update(packed_transaction, update->refname,
+                                          update->flags & ~REF_HAVE_OLD,
+                                          update->new_oid.hash, update->old_oid.hash,
+                                          NULL);
        }
 
        if (packed_refs_lock(refs->packed_ref_store, 0, err)) {
@@ -2714,21 +2778,14 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
                goto cleanup;
        }
 
-       for (i = 0; i < transaction->nr; i++) {
-               struct ref_update *update = transaction->updates[i];
-
-               if ((update->flags & REF_HAVE_NEW) &&
-                   !is_null_oid(&update->new_oid))
-                       add_packed_ref(refs->packed_ref_store, update->refname,
-                                      &update->new_oid);
-       }
-
-       if (commit_packed_refs(refs->packed_ref_store, err)) {
+       if (initial_ref_transaction_commit(packed_transaction, err)) {
                ret = TRANSACTION_GENERIC_ERROR;
                goto cleanup;
        }
 
 cleanup:
+       if (packed_transaction)
+               ref_transaction_free(packed_transaction);
        packed_refs_unlock(refs->packed_ref_store);
        transaction->state = REF_TRANSACTION_CLOSED;
        string_list_clear(&affected_refnames, 0);
@@ -2918,7 +2975,6 @@ struct ref_storage_be refs_be_files = {
        files_initial_transaction_commit,
 
        files_pack_refs,
-       files_peel_ref,
        files_create_symref,
        files_delete_refs,
        files_rename_ref,