%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2001-2010. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
%%
-module(httpd_acceptor).

-include("httpd.hrl").
-include("httpd_internal.hrl").

%% Internal application API
-export([start_link/5, start_link/6]).

%% Other exports (for spawn's etc.)
-export([acceptor_init/6, acceptor_init/7, acceptor_loop/5]).

%%
%% External API
%%

%% start_link

start_link(Manager, SocketType, Addr, Port, ConfigDb, AcceptTimeout) ->
    ?hdrd("start link", 
	  [{manager, Manager}, 
	   {socket_type, SocketType}, 
	   {address, Addr}, 
	   {port, Port}, 
	   {timeout, AcceptTimeout}]),
    Args = [self(), Manager, SocketType, Addr, Port, ConfigDb, AcceptTimeout],
    proc_lib:start_link(?MODULE, acceptor_init, Args).

start_link(Manager, SocketType, ListenSocket, ConfigDb, AcceptTimeout) ->
    ?hdrd("start link", 
	  [{manager, Manager}, 
	   {socket_type, SocketType}, 
	   {listen_socket, ListenSocket}, 
	   {timeout, AcceptTimeout}]),
    Args = [self(), Manager, SocketType, ListenSocket, 
	    ConfigDb, AcceptTimeout],
    proc_lib:start_link(?MODULE, acceptor_init, Args).

acceptor_init(Parent, Manager, SocketType, {ListenOwner, ListenSocket}, 
	      ConfigDb, AcceptTimeout) ->
    ?hdrd("acceptor init", 
	  [{parent, Parent}, 
	   {manager, Manager}, 
	   {socket_type, SocketType}, 
	   {listen_owner, ListenOwner}, 
	   {listen_socket, ListenSocket}, 
	   {timeout, AcceptTimeout}]),
    link(ListenOwner),
    proc_lib:init_ack(Parent, {ok, self()}),
    acceptor_loop(Manager, SocketType, ListenSocket, ConfigDb, AcceptTimeout).

acceptor_init(Parent, Manager, SocketType, Addr, Port, 
	      ConfigDb, AcceptTimeout) ->
    ?hdrd("acceptor init", 
	  [{parent, Parent}, 
	   {manager, Manager}, 
	   {socket_type, SocketType}, 
	   {address, Addr}, 
	   {port, Port}, 
	   {timeout, AcceptTimeout}]),
    case (catch do_init(SocketType, Addr, Port)) of
	{ok, ListenSocket} ->
	    proc_lib:init_ack(Parent, {ok, self()}),
	    acceptor_loop(Manager, SocketType, 
			  ListenSocket, ConfigDb, AcceptTimeout);
	Error ->
	    proc_lib:init_ack(Parent, Error),
	    error
    end.
   
do_init(SocketType, Addr, Port) ->
    ?hdrt("do init", []),
    do_socket_start(SocketType),
    ListenSocket = do_socket_listen(SocketType, Addr, Port),
    {ok, ListenSocket}.


do_socket_start(SocketType) ->
    ?hdrt("do socket start", []),
    case http_transport:start(SocketType) of
	ok ->
	    ok;
	{error, Reason} ->
	    ?hdrv("failed starting transport", [{reason, Reason}]),
	    throw({error, {socket_start_failed, Reason}})
    end.


do_socket_listen(SocketType, Addr, Port) ->
    ?hdrt("do socket listen", []),
    case http_transport:listen(SocketType, Addr, Port) of
	{ok, ListenSocket} ->
	    ListenSocket;
	{error, Reason} ->
	    ?hdrv("listen failed", [{reason,      Reason}, 
				    {socket_type, SocketType},
				    {addr,        Addr},
				    {port,        Port}]),
	    throw({error, {listen, Reason}})
    end.


%% acceptor 

acceptor_loop(Manager, SocketType, ListenSocket, ConfigDb, AcceptTimeout) ->
    ?hdrd("awaiting accept", 
	  [{manager, Manager}, 
	   {socket_type, SocketType}, 
	   {listen_socket, ListenSocket}, 
	   {timeout, AcceptTimeout}]),
    case (catch http_transport:accept(SocketType, ListenSocket, 50000)) of
	{ok, Socket} ->
	    ?hdrv("accepted", [{socket, Socket}]),
	    handle_connection(Manager, ConfigDb, AcceptTimeout, 
			      SocketType, Socket),
	    ?MODULE:acceptor_loop(Manager, SocketType, 
				  ListenSocket, ConfigDb,AcceptTimeout);
	{error, Reason} ->
	    ?hdri("accept failed", [{reason, Reason}]),
	    handle_error(Reason, ConfigDb),
	    ?MODULE:acceptor_loop(Manager, SocketType, ListenSocket, 
				  ConfigDb, AcceptTimeout);
	{'EXIT', _Reason} = EXIT ->
	    ?hdri("accept exited", [{reason, _Reason}]),
	    handle_error(EXIT, ConfigDb),
	    ?MODULE:acceptor_loop(Manager, SocketType, ListenSocket, 
				  ConfigDb, AcceptTimeout)
    end.


handle_connection(Manager, ConfigDb, AcceptTimeout, SocketType, Socket) ->
    {ok, Pid} = httpd_request_handler:start(Manager, ConfigDb, AcceptTimeout),
    http_transport:controlling_process(SocketType, Socket, Pid),
    httpd_request_handler:socket_ownership_transfered(Pid, SocketType, Socket).

handle_error(timeout, _) ->
    ok;

handle_error({enfile, _}, _) ->
    %% Out of sockets...
    sleep(200);

handle_error(emfile, _) ->
    %% Too many open files -> Out of sockets...
    sleep(200);

handle_error(closed, _) ->
    error_logger:info_report("The httpd accept socket was closed by " 
			     "a third party. "
			     "This will not have an impact on inets "
			     "that will open a new accept socket and " 
			     "go on as nothing happened. It does however "
			     "indicate that some other software is behaving "
			     "badly."),
    exit(normal);

%% This will only happen when the client is terminated abnormaly
%% and is not a problem for the server, so we want
%% to terminate normal so that we can restart without any 
%% error messages.
handle_error(econnreset,_) ->
    exit(normal);

handle_error(econnaborted, _) ->
    ok;

handle_error(esslaccept, _) ->
    %% The user has selected to cancel the installation of 
    %% the certifikate, This is not a real error, so we do 
    %% not write an error message.
    ok;

handle_error({'EXIT', Reason}, ConfigDb) ->
    String = lists:flatten(io_lib:format("Accept exit: ~p", [Reason])),
    accept_failed(ConfigDb, String);

handle_error(Reason, ConfigDb) ->
    String = lists:flatten(io_lib:format("Accept error: ~p", [Reason])),
    accept_failed(ConfigDb, String).

-spec accept_failed(_, string()) -> no_return(). 

accept_failed(ConfigDb, String) ->
    error_logger:error_report(String),
    InitData = #init_data{peername =  {0, "unknown"}},
    Info = #mod{config_db = ConfigDb, init_data = InitData},
    mod_log:error_log(Info, String),
    mod_disk_log:error_log(Info, String),
    exit({accept_failed, String}).    

sleep(T) -> receive after T -> ok end.


