105 lines
2.5 KiB
Erlang
105 lines
2.5 KiB
Erlang
%% @Doc Drive a set of fractal BTrees
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-module(fractal_btree_drv).
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-behaviour(gen_server).
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%% API
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-export([start_link/0]).
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-export([
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delete_exist/2,
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lookup_exist/2,
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open/1,
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put/3,
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stop/0]).
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%% gen_server callbacks
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-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
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terminate/2, code_change/3]).
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-define(SERVER, ?MODULE).
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-record(state, { btrees = dict:new() % Map from a name to its tree
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}).
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%%%===================================================================
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start_link() ->
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gen_server:start_link({local, ?SERVER}, ?MODULE, [], []).
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call(X) ->
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gen_server:call(?SERVER, X, infinity).
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lookup_exist(N, K) ->
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call({lookup_exist, N, K}).
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delete_exist(N, K) ->
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call({delete_exist, N, K}).
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open(N) ->
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call({open, N}).
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put(N, K, V) ->
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call({put, N, K, V}).
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stop() ->
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call(stop).
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%%%===================================================================
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init([]) ->
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{ok, #state{}}.
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handle_call({open, N}, _, #state { btrees = D} = State) ->
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case fractal_btree:open(N) of
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{ok, Tree} ->
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{reply, ok, State#state { btrees = dict:store(N, Tree, D)}};
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Otherwise ->
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{reply, {error, Otherwise}, State}
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end;
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handle_call({put, N, K, V}, _, #state { btrees = D} = State) ->
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Tree = dict:fetch(N, D),
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case fractal_btree:put(Tree, K, V) of
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ok ->
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{reply, ok, State};
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Other ->
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{reply, {error, Other}, State}
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end;
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handle_call({delete_exist, N, K}, _, #state { btrees = D} = State) ->
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Tree = dict:fetch(N, D),
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Reply = fractal_btree:delete(Tree, K),
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{reply, Reply, State};
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handle_call({lookup_exist, N, K}, _, #state { btrees = D} = State) ->
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Tree = dict:fetch(N, D),
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Reply = fractal_btree:lookup(Tree, K),
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{reply, Reply, State};
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handle_call(stop, _, State) ->
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cleanup_trees(State),
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{stop, normal, ok, State};
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handle_call(_Request, _From, State) ->
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Reply = ok,
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{reply, Reply, State}.
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handle_cast(_Msg, State) ->
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{noreply, State}.
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handle_info(_Info, State) ->
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{noreply, State}.
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terminate(_Reason, _State) ->
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ok.
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code_change(_OldVsn, State, _Extra) ->
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{ok, State}.
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%%%===================================================================
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%% @todo directory cleanup
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cleanup_trees(#state { btrees = BTs }) ->
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dict:fold(fun(_Name, Tree, ok) ->
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fractal_btree:close(Tree)
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end,
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ok,
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BTs).
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