%% ------------------------------------------------------------------- %% %% 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 '). -behaviour(gen_server). -ifdef(TEST). -include_lib("eunit/include/eunit.hrl"). -endif. %% API -export([start_link/0, stop/0, open/1, is_open/0, get/0, close/1]). %% gen_server callbacks -export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]). -record(state, {conn :: wterl:connection(), monitors :: ets:tid()}). %% ==================================================================== %% API %% ==================================================================== -spec start_link() -> {ok, pid()} | {error, term()}. start_link() -> gen_server:start_link({local, ?MODULE}, ?MODULE, [], []). -spec stop() -> ok. stop() -> gen_server:cast(?MODULE, stop). -spec open(string()) -> {ok, wterl:connection()} | {error, term()}. open(Dir) -> gen_server:call(?MODULE, {open, Dir, self()}, infinity). -spec is_open() -> boolean(). is_open() -> gen_server:call(?MODULE, is_open, infinity). -spec get() -> {ok, reference()} | {error, term()}. get() -> gen_server:call(?MODULE, get, infinity). -spec close(wterl:connection()) -> ok. close(_Conn) -> 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"}, {session_max, 100}], {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(is_open, _From, #state{conn=ConnRef}=State) -> {reply, ConnRef /= undefined, 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 -> do_close(ConnRef), ets:delete(Monitors), State#state{conn=undefined, monitors=undefined}; _ -> State end, {reply, ok, NState}. handle_cast(stop, #state{conn=undefined}=State) -> {noreply, State}; handle_cast(stop, #state{conn=ConnRef, monitors=Monitors}=State) -> do_close(ConnRef), ets:foldl(fun({Monitor, _}, _) -> true = erl:demonitor(Monitor, [flush]) end, true, Monitors), {noreply, State#state{conn=undefined, monitors=undefined}}; 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 -> do_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}) -> do_close(ConnRef), ok. code_change(_OldVsn, State, _Extra) -> {ok, State}. %% ==================================================================== %% Internal functions %% ==================================================================== do_close(undefined) -> ok; do_close(ConnRef) -> wterl:conn_close(ConnRef). -ifdef(TEST). -define(DATADIR, "test/wterl-backend"). simple_test_() -> {spawn, [{setup, fun() -> ?assertCmd("rm -rf " ++ ?DATADIR), ?assertMatch(ok, filelib:ensure_dir(filename:join(?DATADIR, "x"))), {ok, Pid} = start_link(), Pid end, fun(_) -> stop() end, fun(_) -> {inorder, [{"open one connection", fun open_one/0}, {"open two connections", fun open_two/0}, {"open two connections, kill one", fun kill_one/0} ]} end}]}. open_one() -> {ok, Ref} = open("test/wterl-backend"), true = is_open(), close(Ref), false = is_open(), ok. open_and_wait(Pid) -> {ok, Ref} = open("test/wterl-backend"), Pid ! open, receive close -> close(Ref), Pid ! close; exit -> exit(normal) end. open_two() -> Self = self(), Pid1 = spawn_link(fun() -> open_and_wait(Self) end), receive open -> true = is_open() end, Pid2 = spawn_link(fun() -> open_and_wait(Self) end), receive open -> true = is_open() end, Pid1 ! close, receive close -> true = is_open() end, Pid2 ! close, receive close -> false = is_open() end, ok. kill_one() -> Self = self(), Pid1 = spawn_link(fun() -> open_and_wait(Self) end), receive open -> true = is_open() end, Pid2 = spawn_link(fun() -> open_and_wait(Self) end), receive open -> true = is_open() end, Pid1 ! exit, timer:sleep(100), true = is_open(), Pid2 ! close, receive close -> false = is_open() end, ok. -endif.