leveled/src/leveled_iclerk.erl

-module(leveled_iclerk).

-behaviour(gen_server).

-include("../include/leveled.hrl").

-export([init/1,
        handle_call/3,
        handle_cast/2,
        handle_info/2,
        terminate/2,
        clerk_new/1,
        clerk_remove/2,
        clerk_stop/1,
        code_change/3]).      

-include_lib("eunit/include/eunit.hrl").

-define(BATCH_SIZE, 16)
-define(BATCHES_TO_CHECK, 8).

-record(state, {owner :: pid()}).

%%%============================================================================
%%% API
%%%============================================================================

clerk_new(Owner) ->
    {ok, Pid} = gen_server:start(?MODULE, [], []),
    ok = gen_server:call(Pid, {register, Owner}, infinity),
    {ok, Pid}.
    
clerk_remove(Pid, Removals) ->
    gen_server:cast(Pid, {remove, Removals}),
    ok.

clerk_stop(Pid) ->
    gen_server:cast(Pid, stop).

%%%============================================================================
%%% gen_server callbacks
%%%============================================================================

init([]) ->
    {ok, #state{}}.

handle_call({register, Owner}, _From, State) ->
    {reply, ok, State#state{owner=Owner}}.

handle_cast({remove, _Removals}, State) ->
    {noreply, State};
handle_cast(stop, State) ->
    {stop, normal, State}.

handle_info(_Info, State) ->
    {noreply, State}.

terminate(_Reason, _State) ->
    ok.

code_change(_OldVsn, State, _Extra) ->
    {ok, State}.


%%%============================================================================
%%% Internal functions
%%%============================================================================


check_single_file(CDB, _PencilSnapshot, SampleSize, BatchSize) ->
    PositionList = leveled_cdb:cdb_getpositions(CDB, SampleSize),
    KeySizeList = fetch_inbatches(PositionList, BatchSize, CDB, []),
    KeySizeList.
    %% TODO:
    %% Need to check the penciller snapshot to see if these keys are at the
    %% right sequence number
    %%
    %% The calculate the proportion (by value size) of the CDB which is at the
    %% wrong sequence number to help determine eligibility for compaction
    %%
    %% BIG TODO:
    %% Need to snapshot a penciller
    
fetch_inbatches([], _BatchSize, _CDB, CheckedList) ->
    CheckedList;
fetch_inbatches(PositionList, BatchSize, CDB, CheckedList) ->
    {Batch, Tail} = lists:split(BatchSize, PositionList),
    KL_List = leveled_cdb:direct_fetch(CDB, Batch, key_size),
    fetch_inbatches(Tail, BatchSize, CDB, CheckedList ++ KL_List).

window_closed(_Timeout) ->
    true.


%%%============================================================================
%%% Test
%%%============================================================================