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%% Copyright (c) 2011-2012, Loïc Hoguin <[email protected]>
%%
%% Permission to use, copy, modify, and/or distribute this software for any
%% purpose with or without fee is hereby granted, provided that the above
%% copyright notice and this permission notice appear in all copies.
%%
%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
%% @private
-module(ranch_acceptor).
%% API.
-export([start_link/6]).
%% Internal.
-export([init/7]).
-export([loop/7]).
%% API.
-spec start_link(any(), inet:socket(), module(), module(), pid(), pid())
-> {ok, pid()}.
start_link(Ref, LSocket, Transport, Protocol, ListenerPid, ConnsSup) ->
{ok, MaxConns} = ranch_listener:get_max_connections(ListenerPid),
{ok, Opts} = ranch_listener:get_protocol_options(ListenerPid),
Pid = spawn_link(?MODULE, init,
[LSocket, Transport, Protocol, MaxConns, Opts, ListenerPid, ConnsSup]),
ok = ranch_server:add_acceptor(Ref, Pid),
{ok, Pid}.
%% Internal.
-spec init(inet:socket(), module(), module(),
non_neg_integer(), any(), pid(), pid()) -> no_return().
init(LSocket, Transport, Protocol, MaxConns, Opts, ListenerPid, ConnsSup) ->
async_accept(LSocket, Transport),
loop(LSocket, Transport, Protocol, MaxConns, Opts, ListenerPid, ConnsSup).
-spec loop(inet:socket(), module(), module(),
non_neg_integer(), any(), pid(), pid()) -> no_return().
loop(LSocket, Transport, Protocol, MaxConns, Opts, ListenerPid, ConnsSup) ->
receive
%% We couldn't accept the socket but it's safe to continue.
{accept, continue} ->
?MODULE:init(LSocket, Transport, Protocol,
MaxConns, Opts, ListenerPid, ConnsSup);
%% Found my sockets!
{accept, CSocket} ->
{ok, ConnPid} = supervisor:start_child(ConnsSup,
[ListenerPid, CSocket, Transport, Protocol, Opts]),
Transport:controlling_process(CSocket, ConnPid),
ConnPid ! {shoot, ListenerPid},
NbConns = ranch_listener:add_connection(ListenerPid, ConnPid),
{ok, MaxConns2} = maybe_wait(ListenerPid, MaxConns, NbConns),
?MODULE:init(LSocket, Transport, Protocol,
MaxConns2, Opts, ListenerPid, ConnsSup);
%% Upgrade the max number of connections allowed concurrently.
{set_max_conns, MaxConns2} ->
?MODULE:loop(LSocket, Transport, Protocol,
MaxConns2, Opts, ListenerPid, ConnsSup);
%% Upgrade the protocol options.
{set_opts, Opts2} ->
?MODULE:loop(LSocket, Transport, Protocol,
MaxConns, Opts2, ListenerPid, ConnsSup)
end.
-spec maybe_wait(pid(), non_neg_integer(), non_neg_integer())
-> {ok, non_neg_integer()}.
maybe_wait(_, MaxConns, NbConns) when MaxConns > NbConns ->
{ok, MaxConns};
maybe_wait(ListenerPid, MaxConns, NbConns) ->
receive
{set_max_conns, MaxConns2} ->
maybe_wait(ListenerPid, MaxConns2, NbConns)
after 0 ->
NbConns2 = ranch_server:count_connections(ListenerPid),
maybe_wait(ListenerPid, MaxConns, NbConns2)
end.
-spec async_accept(inet:socket(), module()) -> ok.
async_accept(LSocket, Transport) ->
AcceptorPid = self(),
_ = spawn_link(fun() ->
case Transport:accept(LSocket, infinity) of
{ok, CSocket} ->
Transport:controlling_process(CSocket, AcceptorPid),
AcceptorPid ! {accept, CSocket};
%% We want to crash if the listening socket got closed.
{error, Reason} when Reason =/= closed ->
AcceptorPid ! {accept, continue}
end
end),
ok.
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