anchor.diff:  start_link(Bucket, OldMap, NewMap, ProgressCallback) ->
       gen_server:start_link(?MODULE, {Bucket, OldMap, NewMap, ProgressCallback},
                             []).
  -
  -run_code(MainMoverPid, Fun) ->
  -    true = (node() =:= node(MainMoverPid)),
  -    case MainMoverPid =:= self() of
  -        true ->
  -            Fun();
  -        false ->
  -            %% You might be wondering why this trickery is employed
  -            %% here. The reason is this code is called by childs of
  -            %% main mover, which may send them shutdown request. Thus
  -            %% simple direct gen_server:call would cause deadlock. And
  -            %% in fact it was easily happening in initial version of
  -            %% this code.
  -            DoneRef = erlang:make_ref(),
  -            {_, MRef} = erlang:spawn_monitor(
  -                          fun () ->
  -                                  RV = gen_server:call(MainMoverPid, {run_code, Fun}, infinity),
  -                                  exit({DoneRef, RV})
  -                          end),
  -            receive
  -                {'EXIT', MainMoverPid, Reason} ->
  -                    ?log_debug("Got parent exit:~p", [Reason]),
  -                    erlang:demonitor(MRef, [flush]),
  -                    exit(Reason);
  -                {'DOWN', MRef, _, _, Reason} ->
  -                    case Reason of
  -                        {DoneRef, RV} ->
  -                            RV;
  -                        _ ->
  -                            ?log_debug("Worker process crashed: ~p", [Reason]),
  -                            error({run_code_worker_crashed, Reason})
  -                    end
  -            end
  -    end.
   
   %%
   %% gen_server callbacks
  
positive.code:                 all_nodes_set=AllNodesSet}}.
  
  
  handle_call({run_code, Fun}, _From, State) ->
      {reply, Fun(), State};
  handle_call(_, _From, _State) ->
      exit(not_supported).
  
  
negative.code: -define(TAP_STATS_LOGGING_INTERVAL, 10*60*1000).
  
  %% API
  -export([start_link/4]).
  
  %% gen_server callbacks
  -export([code_change/3, init/1, handle_call/3, handle_cast/2, handle_info/2,
  