b325f3e792
* Added copyright notices to files * Added Apache 2.0 License file with permission from Kresten/Trifork * Changed the handle from "Db" to "Tree" because... it made me feel better * Other minor changes here and there
142 lines
3.6 KiB
Erlang
142 lines
3.6 KiB
Erlang
%% @Doc Drive a set of lsm BTrees
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-module(lsm_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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get_exist/2,
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get_fail/2,
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open/1, close/1,
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put/3,
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sync_range/3,
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sync_fold_range/5,
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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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get_exist(N, K) ->
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call({get, N, K}).
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get_fail(N, K) ->
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call({get, 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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close(N) ->
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call({close, N}).
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put(N, K, V) ->
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call({put, N, K, V}).
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sync_range(T, LK, HK) ->
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call({sync_range, T, LK, HK}).
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sync_fold_range(T, Fun, Acc0, LK, HK) ->
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call({sync_fold_range, T, Fun, Acc0, LK, HK}).
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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 lsm_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({close, N}, _, #state { btrees = D} = State) ->
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Tree = dict:fetch(N, D),
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case lsm_btree:close(Tree) of
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ok ->
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{reply, ok, State#state { btrees = dict:erase(N, 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({sync_range, Name, LoKey, HiKey}, _From,
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#state { btrees = D} = State) ->
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Tree = dict:fetch(Name, D),
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{ok, Ref} = lsm_btree:sync_range(Tree, LoKey, HiKey),
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Result = sync_range_gather(Ref),
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{reply, Result, State};
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handle_call({sync_fold_range, Name, Fun, Acc0, LoKey, HiKey},
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_From,
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#state { btrees = D } = State) ->
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Tree = dict:fetch(Name, D),
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Result = lsm_btree:sync_fold_range(Tree, Fun, Acc0, LoKey, HiKey),
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{reply, Result, State};
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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 lsm_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 = lsm_btree:delete(Tree, K),
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{reply, Reply, State};
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handle_call({get, N, K}, _, #state { btrees = D} = State) ->
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Tree = dict:fetch(N, D),
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Reply = lsm_btree:get(Tree, K),
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{reply, Reply, State};
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handle_call(stop, _, #state{ btrees = D } = State ) ->
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[ lsm_btree:close(Tree) || {_,Tree} <- dict:to_list(D) ],
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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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sync_range_gather(Ref) ->
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sync_range_gather(Ref, []).
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sync_range_gather(Ref, Acc) ->
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receive
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{fold_result, Ref, K, V} ->
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sync_range_gather(Ref, [{K, V} | Acc]);
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{fold_done, Ref} ->
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{ok, Acc}
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after 3000 ->
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{error, timeout}
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end.
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