%% Copyright (c) 2011-2017, 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.
-module(cowboy_loop).
-behaviour(cowboy_sub_protocol).
-export([upgrade/4]).
-export([upgrade/5]).
-export([loop/5]).
-export([system_continue/3]).
-export([system_terminate/4]).
-export([system_code_change/4]).
%% From gen_server.
-define(is_timeout(X), ((X) =:= infinity orelse (is_integer(X) andalso (X) >= 0))).
-callback init(Req, any())
-> {ok | module(), Req, any()}
| {module(), Req, any(), any()}
when Req::cowboy_req:req().
-callback info(any(), Req, State)
-> {ok, Req, State}
| {ok, Req, State, hibernate}
| {stop, Req, State}
when Req::cowboy_req:req(), State::any().
-callback terminate(any(), cowboy_req:req(), any()) -> ok.
-optional_callbacks([terminate/3]).
-spec upgrade(Req, Env, module(), any())
-> {ok, Req, Env} | {suspend, ?MODULE, loop, [any()]}
when Req::cowboy_req:req(), Env::cowboy_middleware:env().
upgrade(Req, Env, Handler, HandlerState) ->
loop(Req, Env, Handler, HandlerState, infinity).
-spec upgrade(Req, Env, module(), any(), hibernate | timeout())
-> {suspend, ?MODULE, loop, [any()]}
when Req::cowboy_req:req(), Env::cowboy_middleware:env().
upgrade(Req, Env, Handler, HandlerState, hibernate) ->
suspend(Req, Env, Handler, HandlerState);
upgrade(Req, Env, Handler, HandlerState, Timeout) when ?is_timeout(Timeout) ->
loop(Req, Env, Handler, HandlerState, Timeout).
-spec loop(Req, Env, module(), any(), timeout())
-> {ok, Req, Env} | {suspend, ?MODULE, loop, [any()]}
when Req::cowboy_req:req(), Env::cowboy_middleware:env().
%% @todo Handle system messages.
loop(Req=#{pid := Parent}, Env, Handler, HandlerState, Timeout) ->
receive
%% System messages.
{'EXIT', Parent, Reason} ->
terminate(Req, Env, Handler, HandlerState, Reason);
{system, From, Request} ->
sys:handle_system_msg(Request, From, Parent, ?MODULE, [],
{Req, Env, Handler, HandlerState, Timeout});
%% Calls from supervisor module.
{'$gen_call', From, Call} ->
cowboy_children:handle_supervisor_call(Call, From, [], ?MODULE),
loop(Req, Env, Handler, HandlerState, Timeout);
Message ->
call(Req, Env, Handler, HandlerState, Timeout, Message)
after Timeout ->
call(Req, Env, Handler, HandlerState, Timeout, timeout)
end.
call(Req0, Env, Handler, HandlerState0, Timeout, Message) ->
try Handler:info(Message, Req0, HandlerState0) of
{ok, Req, HandlerState} ->
loop(Req, Env, Handler, HandlerState, Timeout);
{ok, Req, HandlerState, hibernate} ->
suspend(Req, Env, Handler, HandlerState);
{ok, Req, HandlerState, NewTimeout} when ?is_timeout(NewTimeout) ->
loop(Req, Env, Handler, HandlerState, NewTimeout);
{stop, Req, HandlerState} ->
terminate(Req, Env, Handler, HandlerState, stop)
catch Class:Reason:Stacktrace ->
cowboy_handler:terminate({crash, Class, Reason}, Req0, HandlerState0, Handler),
erlang:raise(Class, Reason, Stacktrace)
end.
suspend(Req, Env, Handler, HandlerState) ->
{suspend, ?MODULE, loop, [Req, Env, Handler, HandlerState, infinity]}.
terminate(Req, Env, Handler, HandlerState, Reason) ->
Result = cowboy_handler:terminate(Reason, Req, HandlerState, Handler),
{ok, Req, Env#{result => Result}}.
%% System callbacks.
-spec system_continue(_, _, {Req, Env, module(), any(), timeout()})
-> {ok, Req, Env} | {suspend, ?MODULE, loop, [any()]}
when Req::cowboy_req:req(), Env::cowboy_middleware:env().
system_continue(_, _, {Req, Env, Handler, HandlerState, Timeout}) ->
loop(Req, Env, Handler, HandlerState, Timeout).
-spec system_terminate(any(), _, _, {Req, Env, module(), any(), timeout()})
-> {ok, Req, Env} when Req::cowboy_req:req(), Env::cowboy_middleware:env().
system_terminate(Reason, _, _, {Req, Env, Handler, HandlerState, _}) ->
terminate(Req, Env, Handler, HandlerState, Reason).
-spec system_code_change(Misc, _, _, _) -> {ok, Misc}
when Misc::{cowboy_req:req(), cowboy_middleware:env(), module(), any()}.
system_code_change(Misc, _, _, _) ->
{ok, Misc}.
