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%% @copyright 2011 Hunter Morris
%% @doc Implementation of `gen_server' behaviour.
%% @end
%% Distributed under the MIT license; see LICENSE for details.
-module(bcrypt_pool).
-author('Hunter Morris <huntermorris@gmail.com>').
-behaviour(gen_server).
-export([start_link/0, available/1]).
-export([gen_salt/0, gen_salt/1]).
-export([hashpw/2]).
%% gen_server
-export([init/1, code_change/3, terminate/2,
handle_call/3, handle_cast/2, handle_info/2]).
-record(state, {
size = 0,
busy = 0,
requests = queue:new(),
ports = queue:new()
}).
-record(req, {mon :: reference(), from :: {pid(), atom()}}).
-type state() :: #state{size :: 0, busy :: 0, requests :: queue:queue(), ports :: queue:queue()}.
%% @doc Creates a `gen_server' process as part of a supervision tree.
-spec start_link() -> Result when
Result :: {ok,Pid} | ignore | {error,Error},
Pid :: pid(),
Error :: {already_started,Pid} | term().
start_link() -> gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
%% @doc Asynchronosly check if `Pid' in `#state:requests' queue or not.
-spec available(Pid) -> Result when
Pid :: pid(),
Result :: ok.
available(Pid) -> gen_server:cast(?MODULE, {available, Pid}).
%% @doc Generate a random text salt.
-spec gen_salt() -> Result when
Result :: {ok, Salt},
Salt :: [byte()].
gen_salt() -> do_call(fun bcrypt_port:gen_salt/1, []).
%% @doc Generate a random text salt. Rounds defines the complexity of
%% the hashing, increasing the cost as 2^log_rounds.
-spec gen_salt(Rounds) -> Result when
Rounds :: bcrypt:rounds(),
Result :: {ok, Salt},
Salt :: [byte()].
gen_salt(Rounds) -> do_call(fun bcrypt_port:gen_salt/2, [Rounds]).
%% @doc Hash the specified password and the salt.
hashpw(Password, Salt) -> do_call(fun bcrypt_port:hashpw/3, [Password, Salt]).
%% @private
-spec init([]) -> Result when
Result :: {ok, state()}.
init([]) ->
{ok, Size} = application:get_env(bcrypt, pool_size),
{ok, #state{size = Size}}.
%% @private
terminate(shutdown, _) -> ok.
%% @private
-spec handle_call(Request, From, State) -> Result when
Request :: request,
From :: {RPid, atom()},
RPid :: pid(),
State :: state(),
Result :: {noreply, state()} | {reply, {ok, pid()}, state()}.
handle_call(request, {RPid, _} = From, #state{ports = P} = State) ->
case queue:out(P) of
{empty, P} ->
#state{size = Size, busy = B, requests = R} = State,
B1 =
if Size > B ->
{ok, _} = bcrypt_port_sup:start_child(),
B + 1;
true ->
B
end,
RRef = erlang:monitor(process, RPid),
R1 = queue:in(#req{mon = RRef, from = From}, R),
{noreply, State#state{requests = R1,
busy = B1}};
{{value, PPid}, P1} ->
#state{busy = B} = State,
{reply, {ok, PPid}, State#state{busy = B + 1, ports = P1}}
end;
handle_call(Msg, _, _) -> exit({unknown_call, Msg}).
%% @private
-spec handle_cast({available, Pid}, state()) -> Result when
Pid :: pid(),
Result :: {noreply, state()}.
handle_cast(
{available, Pid},
#state{requests = R, ports = P, busy = B} = S) ->
case queue:out(R) of
{empty, R} ->
{noreply, S#state{ports = queue:in(Pid, P), busy = B - 1}};
{{value, #req{mon = Mon, from = F}}, R1} ->
true = erlang:demonitor(Mon, [flush]),
gen_server:reply(F, {ok, Pid}),
{noreply, S#state{requests = R1}}
end;
handle_cast(Msg, _) -> exit({unknown_cast, Msg}).
%% @private
handle_info({'DOWN', Ref, process, _Pid, _Reason}, #state{requests = R} = State) ->
R1 = queue:from_list(lists:keydelete(Ref, #req.mon, queue:to_list(R))),
{noreply, State#state{requests = R1}};
%% @private
handle_info(Msg, _) -> exit({unknown_info, Msg}).
%% @private
code_change(_OldVsn, State, _Extra) -> {ok, State}.
do_call(F, Args0) ->
{ok, Pid} = gen_server:call(?MODULE, request, infinity),
Args = [Pid|Args0],
apply(F, Args).
|
