wterl/src/wterl_conn.erl

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%% -------------------------------------------------------------------
%%
%% wterl_conn: manage a connection to WiredTiger
%%
%% Copyright (c) 2012 Basho Technologies, Inc. All Rights Reserved.
%%
%% This file is provided to you under the Apache License,
%% Version 2.0 (the "License"); you may not use this file
%% except in compliance with the License. You may obtain
%% a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing,
%% software distributed under the License is distributed on an
%% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
%% KIND, either express or implied. See the License for the
%% specific language governing permissions and limitations
%% under the License.
%%
%% -------------------------------------------------------------------
-module(wterl_conn).
-author('Steve Vinoski <steve@basho.com>').
-behaviour(gen_server).
-ifdef(TEST).
-include_lib("eunit/include/eunit.hrl").
-endif.
%% API
-export([start_link/0,
open/1, get/0, close/0]).
%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
terminate/2, code_change/3]).
-record(state, {conn,
monitors}).
%% ====================================================================
%% API
%% ====================================================================
start_link() ->
gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
open(Dir) ->
gen_server:call(?MODULE, {open, Dir, self()}, infinity).
get() ->
gen_server:call(?MODULE, get, infinity).
close() ->
gen_server:call(?MODULE, {close, self()}, infinity).
%% ====================================================================
%% gen_server callbacks
%% ====================================================================
init([]) ->
{ok, #state{}}.
handle_call({open, Dir, Caller}, _From, #state{conn=undefined}=State) ->
Opts = [{create, true}, {cache_size, "100MB"}],
{Reply, NState} = case wterl:conn_open(Dir, wterl:config_to_bin(Opts)) of
{ok, ConnRef}=OK ->
Monitors = ets:new(?MODULE, []),
Monitor = erlang:monitor(process, Caller),
true = ets:insert(Monitors, {Monitor, Caller}),
{OK, State#state{conn = ConnRef, monitors=Monitors}};
Error ->
{Error, State}
end,
{reply, Reply, NState};
handle_call({open, _Dir, Caller}, _From,#state{conn=ConnRef, monitors=Monitors}=State) ->
Monitor = erlang:monitor(process, Caller),
true = ets:insert(Monitors, {Monitor, Caller}),
{reply, {ok, ConnRef}, State};
handle_call(get, _From, #state{conn=undefined}=State) ->
{reply, {error, "no connection"}, State};
handle_call(get, _From, #state{conn=ConnRef}=State) ->
{reply, {ok, ConnRef}, State};
handle_call({close, Caller}, _From, #state{conn=ConnRef, monitors=Monitors}=State) ->
{[{Monitor, Caller}], _} = ets:match_object(Monitors, {'_', Caller}, 1),
true = erlang:demonitor(Monitor, [flush]),
true = ets:delete(Monitors, Monitor),
NState = case ets:info(Monitors, size) of
0 ->
close(ConnRef),
ets:delete(Monitors),
State#state{conn=undefined, monitors=undefined};
_ ->
State
end,
{reply, ok, NState}.
handle_cast(_Msg, State) ->
{noreply, State}.
handle_info({'DOWN', Monitor, _, _, _}, #state{conn=ConnRef, monitors=Monitors}=State) ->
NState = case ets:lookup(Monitors, Monitor) of
[{Monitor, _}] ->
true = ets:delete(Monitors, Monitor),
case ets:info(Monitors, size) of
0 ->
close(ConnRef),
ets:delete(Monitors),
State#state{conn=undefined, monitors=undefined};
_ ->
State
end;
_ ->
State
end,
{noreply, NState};
handle_info(_Info, State) ->
{noreply, State}.
terminate(_Reason, #state{conn = ConnRef}) ->
close(ConnRef),
ok.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
%% ====================================================================
%% Internal functions
%% ====================================================================
close(undefined) ->
ok;
close(ConnRef) ->
wterl:conn_close(ConnRef).
-ifdef(TEST).
-endif.