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(** Type of parameter for migration functor {!Make}. *)
module type MIGRATION_ACTIONS = sig
  (** Type of store from which data is migrated. *)
  type from_store

  (** Type of store to which the data is migrated. *)
  type dest_store

  (** Action or actions to migrate data associated to a block. NOTE:
      [dest_store] is an empty R/W store initialized in a temporary location. *)
  val migrate_block_action :
    from_store -> dest_store -> Sc_rollup_block.t -> unit tzresult Lwt.t

  (** The final actions to be performed in the migration. In particular, this is
      where data from the temporary store in [dest_store] in [tmp_dir] should be
      reported in the actual [storage_dir]. *)
  val final_actions :
    storage_dir:string ->
    tmp_dir:string ->
    from_store ->
    dest_store ->
    unit tzresult Lwt.t
end

module type S = sig
  (** Migration function for the store located in [storage_dir]. *)
  val migrate :
    Metadata.t ->
    storage_dir:string ->
    index_buffer_size:int ->
    unit tzresult Lwt.t
end

(** Functor to create and {e register} a migration. *)
module Make
    (S_from : Store_sig.S)
    (S_dest : Store_sig.S)
    (Actions : MIGRATION_ACTIONS
                 with type from_store := Store_sigs.ro S_from.t
                  and type dest_store := Store_sigs.rw S_dest.t) : S

(** Migrate store located in rollup node {e store} directory [storage_dir] if
    needed. If there is no possible migration path registered to go from the
    current version to the last {!Store.version}, this function resolves with an
    error. *)
val maybe_run_migration :
  Metadata.t ->
  storage_dir:string ->
  index_buffer_size:int ->
  unit tzresult Lwt.t