couch_replicator_manager.erl

update_rep_doc(RepDbName, RepDocId, KVs) when is_binary(RepDocId) ->
    {Pid, Ref} =
    spawn_monitor(fun() ->
        try
            case fabric:open_doc(mem3:dbname(RepDbName), RepDocId, []) of
                {ok, LatestRepDoc} ->
                    update_rep_doc(RepDbName, LatestRepDoc, KVs);
                _ ->
                    ok
            end
        catch 
        throw:conflict ->
            % a race condition may cause an update conflict,
            % in which cae update_rep_doc is called again to refetch
            twig:log(error, "Conflict error when updating replication document `~s`."
                         " Retrying.", [RepDocId]),
            ok = timer:sleep(5),
            update_rep_doc(RepDbName, RepDocId, KVs);
        Type:Error ->
            exit({Type, Error})
        end
                  end),
    receive
    {'DOWN', Ref, process, Pid, normal} ->
        ok;
    {'DOWN', Ref, process, Pid, {throw, Error}} ->
        throw(Error);
    {'DOWN', Ref, process, Pid, {error, Error}} ->
        erlang:error(Error)
    end;