OctoPrint/octoprint/util/comm.py

from __future__ import absolute_import

import os
import glob
import sys
import time
import math
import re
import traceback
import threading
import Queue as queue
import logging

import serial

from octoprint.util.avr_isp import stk500v2
from octoprint.util.avr_isp import ispBase

from octoprint.settings import settings

try:
	import _winreg
except:
	pass

def isDevVersion():
	gitPath = os.path.abspath(os.path.join(os.path.split(os.path.abspath(__file__))[0], "../../.git"))
	return os.path.exists(gitPath)

def serialList():
	baselist=[]
	if os.name=="nt":
		try:
			key=_winreg.OpenKey(_winreg.HKEY_LOCAL_MACHINE,"HARDWARE\\DEVICEMAP\\SERIALCOMM")
			i=0
			while(1):
				baselist+=[_winreg.EnumValue(key,i)[1]]
				i+=1
		except:
			pass
	baselist = baselist + glob.glob("/dev/ttyUSB*") + glob.glob("/dev/ttyACM*") + glob.glob("/dev/tty.usb*") + glob.glob("/dev/cu.*") + glob.glob("/dev/rfcomm*")
	prev = settings().get(["serial", "port"])
	if prev in baselist:
		baselist.remove(prev)
		baselist.insert(0, prev)
	if isDevVersion():
		baselist.append("VIRTUAL")
	return baselist

def baudrateList():
	ret = [250000, 230400, 115200, 57600, 38400, 19200, 9600]
	prev = settings().getInt(["serial", "baudrate"])
	if prev in ret:
		ret.remove(prev)
		ret.insert(0, prev)
	return ret

class VirtualPrinter():
	def __init__(self):
		self.readList = ['start\n', 'Marlin: Virtual Marlin!\n', '\x80\n']
		self.temp = 0.0
		self.targetTemp = 0.0
		self.lastTempAt = time.time()
		self.bedTemp = 1.0
		self.bedTargetTemp = 1.0

		self._virtualSd = settings().getBaseFolder("virtualSd")
		self._sdPrinter = None
		self._sdPrintingSemaphore = threading.Event()
		self._selectedSdFile = None
		self._selectedSdFileSize = None
		self._selectedSdFilePos = None
		self._writingToSd = False
		self._newSdFilePos = None

		self.currentLine = 0

		waitThread = threading.Thread(target=self._sendWaitAfterTimeout)
		waitThread.start()

	def write(self, data):
		if self.readList is None:
			return

		# shortcut for writing to SD
		if self._writingToSd and not self._selectedSdFile is None and not "M29" in data:
			with open(self._selectedSdFile, "a") as f:
				f.write(data)
			return

		#print "Send: %s" % (data.rstrip())
		if 'M104' in data or 'M109' in data:
			try:
				self.targetTemp = float(re.search('S([0-9]+)', data).group(1))
			except:
				pass
		if 'M140' in data or 'M190' in data:
			try:
				self.bedTargetTemp = float(re.search('S([0-9]+)', data).group(1))
			except:
				pass

		if 'M105' in data:
			# send simulated temperature data
			self.readList.append("ok T:%.2f /%.2f B:%.2f /%.2f @:64\n" % (self.temp, self.targetTemp, self.bedTemp, self.bedTargetTemp))
		elif 'M20' in data:
			self._listSd()
		elif 'M23' in data:
			filename = data.split(None, 1)[1].strip()
			self._selectSdFile(filename)
		elif 'M24' in data:
			self._startSdPrint()
		elif 'M25' in data:
			self._pauseSdPrint()
		elif 'M26' in data:
			pos = int(re.search("S([0-9]+)", data).group(1))
			self._setSdPos(pos)
		elif 'M27' in data:
			self._reportSdStatus()
		elif 'M28' in data:
			filename = data.split(None, 1)[1].strip()
			self._writeSdFile(filename)
		elif 'M29' in data:
			self._finishSdFile()
		elif 'M30' in data:
			filename = data.split(None, 1)[1].strip()
			self._deleteSdFile(filename)
		elif "M110" in data:
			# reset current line
			self.currentLine = int(re.search('N([0-9]+)', data).group(1))
			self.readList.append("ok\n")
		elif self.currentLine == 100:
			# simulate a resend at line 100 of the last 5 lines
			self.readList.append("Error: Line Number is not Last Line Number\n")
			self.readList.append("rs %d\n" % (self.currentLine - 5))
		elif len(data.strip()) > 0:
			self.readList.append("ok\n")

		if "*" in data:
			self.currentLine += 1

	def _listSd(self):
		self.readList.append("Begin file list")
		for osFile in os.listdir(self._virtualSd):
			self.readList.append(osFile.upper())
		self.readList.append("End file list")
		self.readList.append("ok")

	def _selectSdFile(self, filename):
		file = os.path.join(self._virtualSd, filename).lower()
		if not os.path.exists(file) or not os.path.isfile(file):
			self.readList.append("open failed, File: %s." % filename)
		else:
			self._selectedSdFile = file
			self._selectedSdFileSize = os.stat(file).st_size
			self.readList.append("File opened: %s  Size: %d" % (filename, self._selectedSdFileSize))
			self.readList.append("File selected")

	def _startSdPrint(self):
		if self._selectedSdFile is not None:
			if self._sdPrinter is None:
				self._sdPrinter = threading.Thread(target=self._sdPrintingWorker)
				self._sdPrinter.start()
		self._sdPrintingSemaphore.set()
		self.readList.append("ok")

	def _pauseSdPrint(self):
		self._sdPrintingSemaphore.clear()
		self.readList.append("ok")

	def _setSdPos(self, pos):
		self._newSdFilePos = pos

	def _reportSdStatus(self):
		if self._sdPrinter is not None and self._sdPrintingSemaphore.is_set:
			self.readList.append("SD printing byte %d/%d" % (self._selectedSdFilePos, self._selectedSdFileSize))
		else:
			self.readList.append("Not SD printing")

	def _writeSdFile(self, filename):
		file = os.path.join(self._virtualSd, filename).lower()
		if os.path.exists(file):
			if os.path.isfile(file):
				os.remove(file)
			else:
				self.readList.append("error writing to file")

		self._writingToSd = True
		self._selectedSdFile = file
		self.readList.append("ok")

	def _finishSdFile(self):
		self._writingToSd = False
		self._selectedSdFile = None
		self.readList.append("ok")

	def _sdPrintingWorker(self):
		self._selectedSdFilePos = 0
		with open(self._selectedSdFile, "rb") as f:
			for line in f:
				# reset position if requested by client
				if self._newSdFilePos is not None:
					f.seek(self._newSdFilePos)
					self._newSdFilePos = None

				# read current file position
				self._selectedSdFilePos = f.tell()

				# if we are paused, wait for unpausing
				self._sdPrintingSemaphore.wait()

				# set target temps
				if 'M104' in line or 'M109' in line:
					try:
						self.targetTemp = float(re.search('S([0-9]+)', line).group(1))
					except:
						pass
				if 'M140' in line or 'M190' in line:
					try:
						self.bedTargetTemp = float(re.search('S([0-9]+)', line).group(1))
					except:
						pass

				time.sleep(0.01)

		self._sdPrintingSemaphore.clear()
		self._selectedSdFilePos = 0
		self._sdPrinter = None
		self.readList.append("Done printing file")

	def _deleteSdFile(self, filename):
		file = os.path.join(self._virtualSd, filename)
		if os.path.exists(file) and os.path.isfile(file):
			os.remove(file)
		self.readList.append("ok")

	def readline(self):
		if self.readList is None:
			return ''
		n = 0
		timeDiff = self.lastTempAt - time.time()
		self.lastTempAt = time.time()
		if abs(self.temp - self.targetTemp) > 1:
			self.temp += math.copysign(timeDiff * 10, self.targetTemp - self.temp)
			if self.temp < 0:
				self.temp = 0
		if abs(self.bedTemp - self.bedTargetTemp) > 1:
			self.bedTemp += math.copysign(timeDiff * 10, self.bedTargetTemp - self.bedTemp)
			if self.bedTemp < 0:
				self.bedTemp = 0
		while len(self.readList) < 1:
			time.sleep(0.1)
			n += 1
			if n == 20:
				return ''
			if self.readList is None:
				return ''
		time.sleep(0.001)
		return self.readList.pop(0)
	
	def close(self):
		self.readList = None

	def _sendWaitAfterTimeout(self, timeout=5):
		time.sleep(timeout)
		self.readList.append("wait")

class MachineComPrintCallback(object):
	def mcLog(self, message):
		pass
	
	def mcTempUpdate(self, temp, bedTemp, targetTemp, bedTargetTemp):
		pass
	
	def mcStateChange(self, state):
		pass
	
	def mcMessage(self, message):
		pass
	
	def mcProgress(self):
		pass

	def mcZChange(self, newZ):
		pass

	def mcSdFiles(self, files):
		pass

	def mcSdSelected(self, filename, size):
		pass

	def mcSdPrintingDone(self):
		pass

class MachineCom(object):
	STATE_NONE = 0
	STATE_OPEN_SERIAL = 1
	STATE_DETECT_SERIAL = 2
	STATE_DETECT_BAUDRATE = 3
	STATE_CONNECTING = 4
	STATE_OPERATIONAL = 5
	STATE_PRINTING = 6
	STATE_PAUSED = 7
	STATE_CLOSED = 8
	STATE_ERROR = 9
	STATE_CLOSED_WITH_ERROR = 10
	STATE_RECEIVING_FILE = 11
	
	def __init__(self, port = None, baudrate = None, callbackObject = None):
		self._logger = logging.getLogger(__name__)
		self._serialLogger = logging.getLogger("SERIAL")

		if port == None:
			port = settings().get(["serial", "port"])
		if baudrate == None:
			settingsBaudrate = settings().getInt(["serial", "baudrate"])
			if settingsBaudrate is None:
				baudrate = 0
			else:
				baudrate = settingsBaudrate
		if callbackObject == None:
			callbackObject = MachineComPrintCallback()

		self._port = port
		self._baudrate = baudrate
		self._callback = callbackObject
		self._state = self.STATE_NONE
		self._serial = None
		self._baudrateDetectList = baudrateList()
		self._baudrateDetectRetry = 0
		self._temp = 0
		self._bedTemp = 0
		self._targetTemp = 0
		self._bedTargetTemp = 0
		self._gcodeList = None
		self._gcodePos = 0
		self._commandQueue = queue.Queue()
		self._logQueue = queue.Queue(256)
		self._feedRateModifier = {}
		self._currentZ = -1
		self._heatupWaitStartTime = 0
		self._heatupWaitTimeLost = 0.0
		self._printStartTime = None

		self._alwaysSendChecksum = settings().getBoolean(["feature", "alwaysSendChecksum"])
		self._currentLine = 1
		self._resendDelta = None
		self._lastLines = []

		self._sendNextLock = threading.Lock()
		self._sendingLock = threading.Lock()

		self.thread = threading.Thread(target=self._monitor)
		self.thread.daemon = True
		self.thread.start()

		self._sdPrinting = False
		self._sdFileList = False
		self._sdFile = None
		self._sdFilePos = None
		self._sdFileSize = None
		self._sdFiles = []

	def _changeState(self, newState):
		if self._state == newState:
			return

		if newState == self.STATE_CLOSED or newState == self.STATE_CLOSED_WITH_ERROR:
			if settings().get(["feature", "sdSupport"]):
				self._sdPrinting = False
				self._sdFileList = False
				self._sdFile = None
				self._sdFilePos = None
				self._sdFileSize = None
				self._sdFiles = []
				self._callback.mcSdFiles([])

		oldState = self.getStateString()
		self._state = newState
		self._log('Changing monitoring state from \'%s\' to \'%s\'' % (oldState, self.getStateString()))
		self._callback.mcStateChange(newState)
	
	def getState(self):
		return self._state
	
	def getStateString(self):
		if self._state == self.STATE_NONE:
			return "Offline"
		if self._state == self.STATE_OPEN_SERIAL:
			return "Opening serial port"
		if self._state == self.STATE_DETECT_SERIAL:
			return "Detecting serial port"
		if self._state == self.STATE_DETECT_BAUDRATE:
			return "Detecting baudrate"
		if self._state == self.STATE_CONNECTING:
			return "Connecting"
		if self._state == self.STATE_OPERATIONAL:
			return "Operational"
		if self._state == self.STATE_PRINTING:
			if self._sdPrinting:
				return "Printing from SD"
			else:
				return "Printing"
		if self._state == self.STATE_PAUSED:
			return "Paused"
		if self._state == self.STATE_CLOSED:
			return "Closed"
		if self._state == self.STATE_ERROR:
			return "Error: %s" % (self.getShortErrorString())
		if self._state == self.STATE_CLOSED_WITH_ERROR:
			return "Error: %s" % (self.getShortErrorString())
		if self._state == self.STATE_RECEIVING_FILE:
			return "Sending file to SD"
		return "?%d?" % (self._state)
	
	def getShortErrorString(self):
		if len(self._errorValue) < 20:
			return self._errorValue
		return self._errorValue[:20] + "..."

	def getErrorString(self):
		return self._errorValue
	
	def isClosedOrError(self):
		return self._state == self.STATE_ERROR or self._state == self.STATE_CLOSED_WITH_ERROR or self._state == self.STATE_CLOSED

	def isError(self):
		return self._state == self.STATE_ERROR or self._state == self.STATE_CLOSED_WITH_ERROR
	
	def isOperational(self):
		return self._state == self.STATE_OPERATIONAL or self._state == self.STATE_PRINTING or self._state == self.STATE_PAUSED or self._state == self.STATE_RECEIVING_FILE
	
	def isPrinting(self):
		return self._state == self.STATE_PRINTING

	def isSdPrinting(self):
		return self._sdPrinting
	
	def isPaused(self):
		return self._state == self.STATE_PAUSED

	def isBusy(self):
		return self.isPrinting() or self._state == self.STATE_RECEIVING_FILE

	def getPrintPos(self):
		if self._sdPrinting:
			return self._sdFilePos
		else:
			return self._gcodePos
	
	def getPrintTime(self):
		if self._printStartTime == None:
			return 0
		else:
			return time.time() - self._printStartTime

	def getPrintTimeRemainingEstimate(self):
		if self._printStartTime == None:
			return None

		if self._sdPrinting:
			printTime = (time.time() - self._printStartTime) / 60
			if self._sdFilePos > 0:
				printTimeTotal = printTime * (self._sdFileSize / self._sdFilePos)
			else:
				printTimeTotal = printTime * self._sdFileSize
			printTimeLeft = printTimeTotal - printTime
			return printTimeLeft
		else:
			# for host printing we only start counting the print time at gcode line 100, so we need to calculate stuff
			# a bit different here
			if self.getPrintPos() < 200:
				return None
			printTime = (time.time() - self._printStartTime) / 60
			printTimeTotal = printTime * (len(self._gcodeList) - 100) / (self.getPrintPos() - 100)
			printTimeLeft = printTimeTotal - printTime
			return printTimeLeft

	def getSdProgress(self):
		return (self._sdFilePos, self._sdFileSize)

	def getTemp(self):
		return self._temp
	
	def getBedTemp(self):
		return self._bedTemp
	
	def getLog(self):
		ret = []
		while not self._logQueue.empty():
			ret.append(self._logQueue.get())
		for line in ret:
			self._logQueue.put(line, False)
		return ret
	
	def _monitor(self):
		#Open the serial port.
		if self._port == 'AUTO':
			self._changeState(self.STATE_DETECT_SERIAL)
			programmer = stk500v2.Stk500v2()
			self._log("Serial port list: %s" % (str(serialList())))
			for p in serialList():
				try:
					self._log("Connecting to: %s" % (p))
					programmer.connect(p)
					self._serial = programmer.leaveISP()
					break
				except ispBase.IspError as (e):
					self._log("Error while connecting to %s: %s" % (p, str(e)))
					pass
				except:
					self._log("Unexpected error while connecting to serial port: %s %s" % (p, getExceptionString()))
				programmer.close()
		elif self._port == 'VIRTUAL':
			self._changeState(self.STATE_OPEN_SERIAL)
			self._serial = VirtualPrinter()
		else:
			self._changeState(self.STATE_OPEN_SERIAL)
			try:
				self._log("Connecting to: %s" % (self._port))
				if self._baudrate == 0:
					self._serial = serial.Serial(str(self._port), 115200, timeout=0.1, writeTimeout=10000)
				else:
					self._serial = serial.Serial(str(self._port), self._baudrate, timeout=2, writeTimeout=10000)
			except:
				self._log("Unexpected error while connecting to serial port: %s %s" % (self._port, getExceptionString()))
		if self._serial == None:
			self._log("Failed to open serial port (%s)" % (self._port))
			self._errorValue = 'Failed to autodetect serial port.'
			self._changeState(self.STATE_ERROR)
			return
		self._log("Connected to: %s, starting monitor" % (self._serial))
		if self._baudrate == 0:
			self._changeState(self.STATE_DETECT_BAUDRATE)
		else:
			self._changeState(self.STATE_CONNECTING)

		#Start monitoring the serial port.
		timeout = time.time() + 5
		tempRequestTimeout = timeout
		sdStatusRequestTimeout = timeout
		startSeen = not settings().getBoolean(["feature", "waitForStartOnConnect"])
		while True:
			line = self._readline()
			if line == None:
				break

			##~~ Error handling
			# No matter the state, if we see an error, goto the error state and store the error for reference.
			if line.startswith('Error:'):
				#Oh YEAH, consistency.
				# Marlin reports an MIN/MAX temp error as "Error:x\n: Extruder switched off. MAXTEMP triggered !\n"
				#	But a bed temp error is reported as "Error: Temperature heated bed switched off. MAXTEMP triggered !!"
				#	So we can have an extra newline in the most common case. Awesome work people.
				if re.match('Error:[0-9]\n', line):
					line = line.rstrip() + self._readline()
				#Skip the communication errors, as those get corrected.
				if 'checksum mismatch' in line \
						or 'Wrong checksum' in line \
						or 'Line Number is not Last Line Number' in line \
						or 'expected line' in line \
						or 'No Line Number with checksum' in line \
						or 'No Checksum with line number' in line \
						or 'Missing checksum' in line:
					pass
				elif not self.isError():
					self._errorValue = line[6:]
					self._changeState(self.STATE_ERROR)

			##~~ SD file list
			# if we are currently receiving an sd file list, each line is just a filename, so just read it and abort processing
			if self._sdFileList and not 'End file list' in line:
				self._sdFiles.append(line)
				continue

			##~~ Temperature processing
			if ' T:' in line or line.startswith('T:'):
				try:
					self._temp = float(re.search("-?[0-9\.]*", line.split('T:')[1]).group(0))
					if ' B:' in line:
						self._bedTemp = float(re.search("-?[0-9\.]*", line.split(' B:')[1]).group(0))

					self._callback.mcTempUpdate(self._temp, self._bedTemp, self._targetTemp, self._bedTargetTemp)
				except ValueError:
					# catch conversion issues, we'll rather just not get the temperature update instead of killing the connection
					pass

				#If we are waiting for an M109 or M190 then measure the time we lost during heatup, so we can remove that time from our printing time estimate.
				if not 'ok' in line and self._heatupWaitStartTime != 0:
					t = time.time()
					self._heatupWaitTimeLost = t - self._heatupWaitStartTime
					self._heatupWaitStartTime = t

			##~~ SD Card handling
			elif 'Begin file list' in line:
				self._sdFiles = []
				self._sdFileList = True
			elif 'End file list' in line:
				self._sdFileList = False
				self._callback.mcSdFiles(self._sdFiles)
			elif 'SD printing byte' in line:
				# answer to M27, at least on Marlin, Repetier and Sprinter: "SD printing byte %d/%d"
				match = re.search("([0-9]*)/([0-9]*)", line)
				self._sdFilePos = int(match.group(1))
				self._sdFileSize = int(match.group(2))
				self._callback.mcProgress()
			elif 'File opened' in line:
				# answer to M23, at least on Marlin, Repetier and Sprinter: "File opened:%s Size:%d"
				match = re.search("File opened:\s*(.*?)\s+Size:\s*([0-9]*)", line)
				self._sdFile = match.group(1)
				self._sdFileSize = int(match.group(2))
			elif 'File selected' in line:
				# final answer to M23, at least on Marlin, Repetier and Sprinter: "File selected"
				self._callback.mcSdSelected(self._sdFile, self._sdFileSize)
			elif 'Done printing file' in line:
				# printer is reporting file finished printing
				self._sdPrinting = False
				self._sdFilePos = 0
				self._changeState(self.STATE_OPERATIONAL)
				self._callback.mcSdPrintingDone()

			##~~ Message handling
			elif line.strip() != '' and line.strip() != 'ok' and not line.startswith("wait") and not line.startswith('Resend:') and line != 'echo:Unknown command:""\n' and self.isOperational():
				self._callback.mcMessage(line)

			### Baudrate detection
			if self._state == self.STATE_DETECT_BAUDRATE:
				if line == '' or time.time() > timeout:
					if len(self._baudrateDetectList) < 1:
						self.close()
						self._errorValue = "No more baudrates to test, and no suitable baudrate found."
						self._changeState(self.STATE_ERROR)
					elif self._baudrateDetectRetry > 0:
						self._baudrateDetectRetry -= 1
						self._serial.write('\n')
						self._log("Baudrate test retry: %d" % (self._baudrateDetectRetry))
						self._sendCommand("M105")
						self._testingBaudrate = True
					else:
						baudrate = self._baudrateDetectList.pop(0)
						try:
							self._serial.baudrate = baudrate
							self._serial.timeout = 0.5
							self._log("Trying baudrate: %d" % (baudrate))
							self._baudrateDetectRetry = 5
							self._baudrateDetectTestOk = 0
							timeout = time.time() + 5
							self._serial.write('\n')
							self._sendCommand("M105")
							self._testingBaudrate = True
						except:
							self._log("Unexpected error while setting baudrate: %d %s" % (baudrate, getExceptionString()))
				elif 'ok' in line and 'T:' in line:
					self._baudrateDetectTestOk += 1
					if self._baudrateDetectTestOk < 10:
						self._log("Baudrate test ok: %d" % (self._baudrateDetectTestOk))
						self._sendCommand("M105")
					else:
						self._sendCommand("M999")
						self._serial.timeout = 2
						self._changeState(self.STATE_OPERATIONAL)
				else:
					self._testingBaudrate = False

			### Connection attempt
			elif self._state == self.STATE_CONNECTING:
				if (line == "" or "wait" in line) and startSeen:
					self._sendCommand("M105")
				elif "start" in line:
					startSeen = True
				elif "ok" in line and startSeen:
					self._changeState(self.STATE_OPERATIONAL)
					if settings().get(["feature", "sdSupport"]):
						self._sendCommand("M20")
				elif time.time() > timeout:
					self.close()

			### Operational
			elif self._state == self.STATE_OPERATIONAL or self._state == self.STATE_PAUSED:
				#Request the temperature on comm timeout (every 5 seconds) when we are not printing.
				if line == "" or "wait" in line:
					if self._resendDelta is not None:
						self._resendNextCommand()
					elif not self._commandQueue.empty():
						self._sendCommand(self._commandQueue.get())
					else:
						self._sendCommand("M105")
					tempRequestTimeout = time.time() + 5
				# resend -> start resend procedure from requested line
				elif "resend" in line.lower() or "rs" in line:
					self._handleResendRequest(line)

			### Printing
			elif self._state == self.STATE_PRINTING:
				if line == "" and time.time() > timeout:
					self._log("Communication timeout during printing, forcing a line")
					line = 'ok'

				# Even when printing request the temperature every 5 seconds.
				if time.time() > tempRequestTimeout:
					self._commandQueue.put("M105")
					tempRequestTimeout = time.time() + 5

				if self._sdPrinting:
					if time.time() > sdStatusRequestTimeout:
						self._commandQueue.put("M27")
						sdStatusRequestTimeout = time.time() + 1

					if 'ok' in line and not self._commandQueue.empty():
						self._sendCommand(self._commandQueue.get())
				else:
					if 'ok' in line:
						timeout = time.time() + 5
                        if self._resendDelta is not None:
                            self._resendNextCommand()
                        elif not self._commandQueue.empty():
							self._sendCommand(self._commandQueue.get())
						else:
							self._sendNext()
					elif "resend" in line.lower() or "rs" in line:
						self._handleResendRequest(line)
		self._log("Connection closed, closing down monitor")

	def _handleResendRequest(self, line):
		lineToResend = None
		try:
			lineToResend = int(line.replace("N:"," ").replace("N"," ").replace(":"," ").split()[-1])
		except:
			if "rs" in line:
				lineToResend = int(line.split()[1])

		if lineToResend is not None:
			self._resendDelta = self._currentLine - lineToResend
			if self._resendDelta > len(self._lastLines):
				self._errorValue = "Printer requested line %d but history is only available up to line %d" % (lineToResend, self._currentLine - len(self._lastLines))
				self._changeState(self.STATE_ERROR)
				self._logger.warn(self._errorValue)
			else:
				self._resendNextCommand()

	def _log(self, message):
		self._callback.mcLog(message)
		self._serialLogger.debug(message)
		try:
			self._logQueue.put(message, False)
		except:
			#If the log queue is full, remove the first message and append the new message again
			self._logQueue.get()
			try:
				self._logQueue.put(message, False)
			except:
				pass

	def _readline(self):
		if self._serial == None:
			return None
		try:
			ret = self._serial.readline()
		except:
			self._log("Unexpected error while reading serial port: %s" % (getExceptionString()))
			self._errorValue = getExceptionString()
			self.close(True)
			return None
		if ret == '':
			#self._log("Recv: TIMEOUT")
			return ''
		self._log("Recv: %s" % (unicode(ret, 'ascii', 'replace').encode('ascii', 'replace').rstrip()))
		return ret
	
	def close(self, isError = False):
		if self._serial != None:
			self._serial.close()
			if isError:
				self._changeState(self.STATE_CLOSED_WITH_ERROR)
			else:
				self._changeState(self.STATE_CLOSED)
		self._serial = None

		if settings().get(["feature", "sdSupport"]):
			self._sdFileList = []

	def __del__(self):
		self.close()

	def _resendNextCommand(self):
		# Make sure we are only handling one sending job at a time
		with self._sendingLock:
			self._logger.debug("Resending line %d, delta is %d, history log is %s items strong" % (self._currentLine - self._resendDelta, self._resendDelta, len(self._lastLines)))
			cmd = self._lastLines[-self._resendDelta]
			lineNumber = self._currentLine - self._resendDelta

			self._doSendWithChecksum(cmd, lineNumber)

			self._resendDelta -= 1
			if self._resendDelta <= 0:
				self._resendDelta = None

	def _sendCommand(self, cmd, sendChecksum=False):
		# Make sure we are only handling one sending job at a time
		with self._sendingLock:
			if self._serial is None:
				return
			if 'M109' in cmd or 'M190' in cmd:
				self._heatupWaitStartTime = time.time()
			if 'M104' in cmd or 'M109' in cmd:
				try:
					self._targetTemp = float(re.search('S([0-9]+)', cmd).group(1))
				except:
					pass
			if 'M140' in cmd or 'M190' in cmd:
				try:
					self._bedTargetTemp = float(re.search('S([0-9]+)', cmd).group(1))
				except:
					pass

			if "M110" in cmd:
				newLineNumber = None
				if " N" in cmd:
					try:
						newLineNumber = int(re.search("N([0-9]+)", cmd).group(1))
					except:
						pass
				else:
					newLineNumber = 0

				if settings().getBoolean(["feature", "resetLineNumbersWithPrefixedN"]) and newLineNumber is not None:
					# let's rewrite the M110 command to fit repetier syntax
					self._addToLastLines(cmd)
					self._doSendWithChecksum("M110", newLineNumber)
				else:
					self._doSend(cmd, sendChecksum)

				if newLineNumber is not None:
					self._currentLine = newLineNumber + 1

				# after a reset of the line number we have no way to determine what line exactly the printer now wants
				self._lastLines = []
				self._resendDelta = None
			else:
				self._doSend(cmd, sendChecksum)

	def _addToLastLines(self, cmd):
		self._lastLines.append(cmd)
		if len(self._lastLines) > 50:
			self._lastLines = self._lastLines[-50:] # only keep the last 50 lines in memory
		self._logger.debug("Got %d lines of history in memory" % len(self._lastLines))

	def _doSend(self, cmd, sendChecksum=False):
		if sendChecksum or self._alwaysSendChecksum:
			if self._alwaysSendChecksum:
				lineNumber = self._currentLine
			else:
				lineNumber = self._gcodePos
			self._addToLastLines(cmd)
			self._currentLine += 1
			self._doSendWithChecksum(cmd, lineNumber)
		else:
			self._doSendWithoutChecksum(cmd)

	def _doSendWithChecksum(self, cmd, lineNumber):
		self._logger.debug("Sending cmd '%s' with lineNumber %r" % (cmd, lineNumber))

		checksum = reduce(lambda x,y:x^y, map(ord, "N%d%s" % (lineNumber, cmd)))
		commandToSend = "N%d%s*%d" % (lineNumber, cmd, checksum)
		self._doSendWithoutChecksum(commandToSend)

	def _doSendWithoutChecksum(self, cmd):
		self._log("Send: %s" % cmd)
		try:
			self._serial.write(cmd + '\n')
		except serial.SerialTimeoutException:
			self._log("Serial timeout while writing to serial port, trying again.")
			try:
				self._serial.write(cmd + '\n')
			except:
				self._log("Unexpected error while writing serial port: %s" % (getExceptionString()))
				self._errorValue = getExceptionString()
				self.close(True)
		except:
			self._log("Unexpected error while writing serial port: %s" % (getExceptionString()))
			self._errorValue = getExceptionString()
			self.close(True)

	def _sendNext(self):
		with self._sendNextLock:
			if self._gcodePos >= len(self._gcodeList):
				self._changeState(self.STATE_OPERATIONAL)
				return
			if self._gcodePos == 100:
				self._printStartTime100 = time.time()
			line = self._gcodeList[self._gcodePos]
			if type(line) is tuple:
				self._printSection = line[1]
				line = line[0]
			try:
				if line == 'M0' or line == 'M1':
					self.setPause(True)
					line = 'M105'	#Don't send the M0 or M1 to the machine, as M0 and M1 are handled as an LCD menu pause.
				if self._printSection in self._feedRateModifier:
					line = re.sub('F([0-9]*)', lambda m: 'F' + str(int(int(m.group(1)) * self._feedRateModifier[self._printSection])), line)
				if ('G0' in line or 'G1' in line) and 'Z' in line:
					z = float(re.search('Z([0-9\.]*)', line).group(1))
					if self._currentZ != z:
						self._currentZ = z
						self._callback.mcZChange(z)
			except:
				self._log("Unexpected error: %s" % (getExceptionString()))
			self._sendCommand(line, True)
			self._gcodePos += 1
			self._callback.mcProgress(self._gcodePos)
	
	def sendCommand(self, cmd):
		cmd = cmd.encode('ascii', 'replace')
		if self.isPrinting():
			self._commandQueue.put(cmd)
		elif self.isOperational():
			self._sendCommand(cmd)
	
	def printGCode(self, gcodeList):
		if not self.isOperational() or self.isPrinting():
			return
		if self._sdPrinting:
			self._sdPrinting = False
		self._gcodeList = gcodeList
		self._gcodePos = 0
		self._printSection = 'CUSTOM'
		self._changeState(self.STATE_PRINTING)
		self._printStartTime = time.time()
		self._sendNext()

	def selectSdFile(self, filename):
		if not self.isOperational() or self.isPrinting():
			return
		self._sdFile = None
		self._sdFilePos = 0

		self.sendCommand("M23 %s" % filename.lower())

	def printSdFile(self):
		if not self.isOperational() or self.isPrinting():
			return

		if self.isPaused():
			self.sendCommand("M26 S0") # reset position in file to byte 0
		self.sendCommand("M24")

		self._printSection = 'CUSTOM'
		self._sdPrinting = True
		self._changeState(self.STATE_PRINTING)
		self._printStartTime = time.time()

	def cancelPrint(self):
		if self.isOperational():
			self._changeState(self.STATE_OPERATIONAL)
		if self._sdPrinting:
			self._sdPrinting = False
			self.sendCommand("M25")    # pause print
			self.sendCommand("M26 S0") # reset position in file to byte 0
	
	def setPause(self, pause):
		if not pause and self.isPaused():
			self._changeState(self.STATE_PRINTING)
			if self._sdPrinting:
				self.sendCommand("M24")
			else:
				for i in xrange(0, 6):
					self._sendNext()
		if pause and self.isPrinting():
			self._changeState(self.STATE_PAUSED)
			if self._sdPrinting:
				self.sendCommand("M25") # pause print

	def setFeedrateModifier(self, type, value):
		self._feedRateModifier[type] = value

	def getFeedrateModifiers(self):
		result = {}
		result.update(self._feedRateModifier)
		return result

	def getSdFiles(self):
		return self._sdFiles

	def startSdFileTransfer(self, filename):
		if self.isPrinting() or self.isPaused():
			return
		self._changeState(self.STATE_RECEIVING_FILE)
		self.sendCommand("M28 %s" % filename.lower())

	def endSdFileTransfer(self, filename):
		self.sendCommand("M29 %s" % filename.lower())
		self._changeState(self.STATE_OPERATIONAL)
		self.sendCommand("M20")

	def deleteSdFile(self, filename):
		self.sendCommand("M30 %s" % filename.lower())
		self.sendCommand("M20")

def getExceptionString():
	locationInfo = traceback.extract_tb(sys.exc_info()[2])[0]
	return "%s: '%s' @ %s:%s:%d" % (str(sys.exc_info()[0].__name__), str(sys.exc_info()[1]), os.path.basename(locationInfo[0]), locationInfo[2], locationInfo[1])