-- 

-- server.lua by blastbeat of the luadch project

-- Re-used here under the MIT/X Consortium License

-- 

-- Modifications (C) 2008-2010 Matthew Wild, Waqas Hussain

--

-- // wrapping luadch stuff // --

local use = function( what )

	return _G[ what ]

end

local clean = function( tbl )

	for i, k in pairs( tbl ) do

		tbl[ i ] = nil

	end

end

local log, table_concat = require ("util.logger").init("socket"), table.concat;

local out_put = function (...) return log("debug", table_concat{...}); end

local out_error = function (...) return log("warn", table_concat{...}); end

----------------------------------// DECLARATION //--

--// constants //--

local STAT_UNIT = 1 -- byte

--// lua functions //--

local type = use "type"

local pairs = use "pairs"

local ipairs = use "ipairs"

local tonumber = use "tonumber"

local tostring = use "tostring"

--// lua libs //--

local os = use "os"

local table = use "table"

local string = use "string"

local coroutine = use "coroutine"

--// lua lib methods //--

local os_difftime = os.difftime

local math_min = math.min

local math_huge = math.huge

local table_concat = table.concat

local string_len = string.len

local string_sub = string.sub

local coroutine_wrap = coroutine.wrap

local coroutine_yield = coroutine.yield

--// extern libs //--

local luasec = use "ssl"

local luasocket = use "socket" or require "socket"

local luasocket_gettime = luasocket.gettime

--// extern lib methods //--

local ssl_wrap = ( luasec and luasec.wrap )

local socket_bind = luasocket.bind

local socket_sleep = luasocket.sleep

local socket_select = luasocket.select

--// functions //--

local id

local loop

local stats

local idfalse

local closeall

local addsocket

local addserver

local getserver

local wrapserver

local getsettings

local closesocket

local removesocket

local removeserver

local wrapconnection

local changesettings

--// tables //--

local _server

local _readlist

local _timerlist

local _sendlist

local _socketlist

local _closelist

local _readtimes

local _writetimes

--// simple data types //--

local _

local _readlistlen

local _sendlistlen

local _timerlistlen

local _sendtraffic

local _readtraffic

local _selecttimeout

local _sleeptime

local _starttime

local _currenttime

local _maxsendlen

local _maxreadlen

local _checkinterval

local _sendtimeout

local _readtimeout

local _cleanqueue

local _timer

local _maxclientsperserver

local _maxsslhandshake

----------------------------------// DEFINITION //--

_server = { } -- key = port, value = table; list of listening servers

_readlist = { } -- array with sockets to read from

_sendlist = { } -- arrary with sockets to write to

_timerlist = { } -- array of timer functions

_socketlist = { } -- key = socket, value = wrapped socket (handlers)

_readtimes = { } -- key = handler, value = timestamp of last data reading

_writetimes = { } -- key = handler, value = timestamp of last data writing/sending

_closelist = { } -- handlers to close

_readlistlen = 0 -- length of readlist

_sendlistlen = 0 -- length of sendlist

_timerlistlen = 0 -- lenght of timerlist

_sendtraffic = 0 -- some stats

_readtraffic = 0

_selecttimeout = 1 -- timeout of socket.select

_sleeptime = 0 -- time to wait at the end of every loop

_maxsendlen = 51000 * 1024 -- max len of send buffer

_maxreadlen = 25000 * 1024 -- max len of read buffer

_checkinterval = 1200000 -- interval in secs to check idle clients

_sendtimeout = 60000 -- allowed send idle time in secs

_readtimeout = 6 * 60 * 60 -- allowed read idle time in secs

_cleanqueue = false -- clean bufferqueue after using

_maxclientsperserver = 1000

_maxsslhandshake = 30 -- max handshake round-trips

----------------------------------// PRIVATE //--

wrapserver = function( listeners, socket, ip, serverport, pattern, sslctx, maxconnections ) -- this function wraps a server

	maxconnections = maxconnections or _maxclientsperserver

	local connections = 0

	local dispatch, disconnect = listeners.onconnect, listeners.ondisconnect

	local accept = socket.accept

	--// public methods of the object //--

	local handler = { }

	handler.shutdown = function( ) end

	handler.ssl = function( )

		return sslctx ~= nil

	end

	handler.sslctx = function( )

		return sslctx

	end

	handler.remove = function( )

		connections = connections - 1

	end

	handler.close = function()

		socket:close( )

		_sendlistlen = removesocket( _sendlist, socket, _sendlistlen )

		_readlistlen = removesocket( _readlist, socket, _readlistlen )

		_server[ip..":"..serverport] = nil;

		_socketlist[ socket ] = nil

		handler = nil

		socket = nil

		--mem_free( )

		out_put "server.lua: closed server handler and removed sockets from list"

	end

	handler.ip = function( )

		return ip

	end

	handler.serverport = function( )

		return serverport

	end

	handler.socket = function( )

		return socket

	end

	handler.readbuffer = function( )

		if connections > maxconnections then

			out_put( "server.lua: refused new client connection: server full" )

			return false

		end

		local client, err = accept( socket )	-- try to accept

		if client then

			local ip, clientport = client:getpeername( )

			client:settimeout( 0 )

			local handler, client, err = wrapconnection( handler, listeners, client, ip, serverport, clientport, pattern, sslctx ) -- wrap new client socket

			if err then -- error while wrapping ssl socket

				return false

			end

			connections = connections + 1

			out_put( "server.lua: accepted new client connection from ", tostring(ip), ":", tostring(clientport), " to ", tostring(serverport))

			if dispatch then

				return dispatch( handler );

			end

			return;

		elseif err then -- maybe timeout or something else

			out_put( "server.lua: error with new client connection: ", tostring(err) )

			return false

		end

	end

	return handler

end

wrapconnection = function( server, listeners, socket, ip, serverport, clientport, pattern, sslctx ) -- this function wraps a client to a handler object

	socket:settimeout( 0 )

	--// local import of socket methods //--

	local send

	local receive

	local shutdown

	--// private closures of the object //--

	local ssl

	local dispatch = listeners.onincoming

	local status = listeners.onstatus

	local disconnect = listeners.ondisconnect

	local drain = listeners.ondrain

	local bufferqueue = { } -- buffer array

	local bufferqueuelen = 0	-- end of buffer array

	local toclose

	local fatalerror

	local needtls

	local bufferlen = 0

	local noread = false

	local nosend = false

	local sendtraffic, readtraffic = 0, 0

	local maxsendlen = _maxsendlen

	local maxreadlen = _maxreadlen

	--// public methods of the object //--

	local handler = bufferqueue -- saves a table ^_^

	handler.dispatch = function( )

		return dispatch

	end

	handler.disconnect = function( )

		return disconnect

	end

	handler.setlistener = function( self, listeners )

		dispatch = listeners.onincoming

		disconnect = listeners.ondisconnect

		status = listeners.onstatus

		drain = listeners.ondrain

	end

	handler.getstats = function( )

		return readtraffic, sendtraffic

	end

	handler.ssl = function( )

		return ssl

	end

	handler.sslctx = function ( )

		return sslctx

	end

	handler.send = function( _, data, i, j )

		return send( socket, data, i, j )

	end

	handler.receive = function( pattern, prefix )

		return receive( socket, pattern, prefix )

	end

	handler.shutdown = function( pattern )

		return shutdown( socket, pattern )

	end

	handler.setoption = function (self, option, value)

		if socket.setoption then

			return socket:setoption(option, value);

		end

		return false, "setoption not implemented";

	end

	handler.force_close = function ( self, err )

		if bufferqueuelen ~= 0 then

			out_put("server.lua: discarding unwritten data for ", tostring(ip), ":", tostring(clientport))

			for i = bufferqueuelen, 1, -1 do

				bufferqueue[i] = nil;

			end

			bufferqueuelen = 0;

		end

		return self:close(err);

	end

	handler.close = function( self, err )

		if not handler then return true; end

		_readlistlen = removesocket( _readlist, socket, _readlistlen )

		_readtimes[ handler ] = nil

		if bufferqueuelen ~= 0 then

			handler.sendbuffer() -- Try now to send any outstanding data

			if bufferqueuelen ~= 0 then -- Still not empty, so we'll try again later

				if handler then

					handler.write = nil -- ... but no further writing allowed

				end

				toclose = true

				return false

			end

		end

		if socket then

			_ = shutdown and shutdown( socket )

			socket:close( )

			_sendlistlen = removesocket( _sendlist, socket, _sendlistlen )

			_socketlist[ socket ] = nil

			socket = nil

		else

			out_put "server.lua: socket already closed"

		end

		if handler then

			_writetimes[ handler ] = nil

			_closelist[ handler ] = nil

			local _handler = handler;

			handler = nil

			if disconnect then

				disconnect(_handler, err or false);

				disconnect = nil

			end

		end

		if server then

			server.remove( )

		end

		out_put "server.lua: closed client handler and removed socket from list"

		return true

	end

	handler.ip = function( )

		return ip

	end

	handler.serverport = function( )

		return serverport

	end

	handler.clientport = function( )

		return clientport

	end

	local write = function( self, data )

		bufferlen = bufferlen + string_len( data )

		if bufferlen > maxsendlen then

			_closelist[ handler ] = "send buffer exceeded"	 -- cannot close the client at the moment, have to wait to the end of the cycle

			handler.write = idfalse -- dont write anymore

			return false

		elseif socket and not _sendlist[ socket ] then

			_sendlistlen = addsocket(_sendlist, socket, _sendlistlen)

		end

		bufferqueuelen = bufferqueuelen + 1