]).
--record(state, {id :: integer()
+-record(state, {cell_id :: integer()
,name :: string()
,cell_state :: 0 | 1
,neighbors :: list(atom())
,live_neighbors :: integer()
,num_neighbors :: integer()
,replies_pending :: integer()
+ ,gen_id :: integer()
}).
%% API
%% ============================================================================
-start_link({_ID, Name, _NeighborNames}=Datum) ->
+start_link({_, Name, _}=Datum) ->
ServerName = {local, Name},
Args = [Datum],
Opts = [],
%% Callbacks
%% ============================================================================
-init([{ID, Name, NeighborNames}]) ->
- State = #state{id=ID
- ,name=Name
- ,cell_state=crypto:rand_uniform(0, 2)
- ,neighbors=NeighborNames
- ,num_neighbors=length(NeighborNames)
- ,live_neighbors=0
- ,replies_pending=0
+init([{CellID, Name, NeighborNames}]) ->
+ State = #state{cell_id = CellID
+ ,name = Name
+ ,cell_state = crypto:rand_uniform(0, 2)
+ ,neighbors = NeighborNames
+ ,num_neighbors = length(NeighborNames)
+ ,live_neighbors = 0
+ ,replies_pending = 0
},
{ok, State}.
{reply, ok, State}.
-handle_cast(tick,
- #state{name=Name
+handle_cast({next_gen, GenID},
+ #state{cell_state=CellState
,neighbors=Neighbors
,num_neighbors=NumNeighbors
}=State) ->
- ok = cast_all(Neighbors, {request_state, Name}),
- {noreply, State#state{replies_pending=NumNeighbors}};
+ ok = cast_all(Neighbors, {state_broadcast, GenID, CellState}),
+ {noreply, State#state{replies_pending=NumNeighbors, gen_id=GenID}};
-handle_cast({request_state, Requester}, State) ->
- ok = gen_server:cast(Requester, {response_state, State#state.cell_state}),
+
+%% If we receive 'state_broadcast' before we receive 'next_gen', throw it back
+%% in the queue. (Took me a while to realize this, but sometimes it is
+%% possible. The more there're cells, the more likely this is to happen.)
+handle_cast({state_broadcast, ReceivedGenID, _NeighborState}=Msg,
+ #state{gen_id=GenID, name=Name}=State) when GenID =/= ReceivedGenID->
+ gen_server:cast(Name, Msg),
{noreply, State};
-handle_cast({response_state, NeighborState},
- #state{id=ID
+%% Now that we can be sure that this request is for the current generation, we
+%% can handle it
+handle_cast({state_broadcast, GenID, NeighborState},
+ #state{cell_id=CellID
+ ,gen_id=GenID
,replies_pending=Pending
,cell_state=CellState
,live_neighbors=LiveNeighbors
case NewPending of
0 ->
NewCellState = new_state(CellState, NewLiveNeighbors),
- ok = life_time:tock(ID, NewCellState),
+ ok = life_time:report_state(CellID, GenID, NewCellState),
{noreply, NewState#state{live_neighbors=0
,cell_state=NewCellState