Smoothie compat fix: Only wait for ok's after GCODE commands

Any unknown commands should just be piped through and not use up an acknowledgement. This
new behaviour can be overridden via the new feature flag "unknownCommandsNeedAck", which will
restore the former behaviour causing even unknown commands to use up an "ok".

Also no line numbering or checksumming will happen. Shouldn't usually be of relevance for other
firmwares, but in case of any compatibility issues introduced by this also added a new feature
flag "sendChecksumWithNonGcode" that causes even unknown commands to be sent with a
checksum if necessary.

docs/configuration/config_yaml.rst

@@ -373,10 +373,18 @@ Use the following settings to enable or disable OctoPrint features:
      # during connect.
      waitForStartOnConnect: false
 
-     # Specifies whether OctoPrint should send linenumber + checksum with every command. Needed for
+     # Specifies whether OctoPrint should send linenumber + checksum with every printer command. Needed for
      # successful communication with Repetier firmware
      alwaysSendChecksum: false
 
+     # Specifies whether OctoPrint should also send linenumber + checksum with commands that are *not*
+     # detected as valid GCODE (as in, they do not match the regular expression "^\s*([GM]\d+|T)").
+     sendChecksumWithUnknownCommands: false
+
+     # Specifies whether OctoPrint should also use up acknowledgments ("ok") for commands that are *not*
+     # detected as valid GCODE (as in, they do not match the regular expression "^\s*([GM]\d+|T)").
+     unknownCommandsNeedAck: false
+
      # Whether to ignore the first ok after a resend response. Needed for successful communication with
      # Repetier firmware
      swallowOkAfterResend: false

src/octoprint/plugins/virtual_printer/virtual.py

@@ -149,6 +149,11 @@ class VirtualPrinter():
 				self._sendOk()
 				continue
 
+			if data.strip() == "version":
+				from octoprint._version import get_versions
+				self.outgoing.put("OctoPrint VirtualPrinter v" + get_versions()["version"])
+				continue
+
 			if len(data.strip()) > 0 and self._okBeforeCommandOutput:
 				self._sendOk()
 
@@ -394,7 +399,6 @@ class VirtualPrinter():
 				pass
 
 		if tool >= settings().getInt(["devel", "virtualPrinter", "numExtruders"]):
-			self._sendOk()
 			return
 
 		try:
@@ -406,7 +410,6 @@ class VirtualPrinter():
 			self._waitForHeatup("tool%d" % tool)
 		if settings().getBoolean(["devel", "virtualPrinter", "repetierStyleTargetTemperature"]):
 			self.outgoing.put("TargetExtr%d:%d" % (tool, self.targetTemp[tool]))
-		self._sendOk()
 
 	def _parseBedCommand(self, line):
 		try:
@@ -418,7 +421,6 @@ class VirtualPrinter():
 			self._waitForHeatup("bed")
 		if settings().getBoolean(["devel", "virtualPrinter", "repetierStyleTargetTemperature"]):
 			self.outgoing.put("TargetBed:%d" % self.bedTargetTemp)
-		self._sendOk()
 
 	def _performMove(self, line):
 		matchX = re.search("X([0-9.]+)", line)

src/octoprint/settings.py

@@ -132,6 +132,8 @@ default_settings = {
 		"temperatureGraph": True,
 		"waitForStartOnConnect": False,
 		"alwaysSendChecksum": False,
+		"sendChecksumWithUnknownCommands": False,
+		"unknownCommandsNeedAck": False,
 		"sdSupport": True,
 		"sdAlwaysAvailable": False,
 		"swallowOkAfterResend": True,

src/octoprint/util/comm.py

@@ -155,6 +155,8 @@ class MachineCom(object):
 		self._timeout = None
 
 		self._alwaysSendChecksum = settings().getBoolean(["feature", "alwaysSendChecksum"])
+		self._sendChecksumWithUnknownCommands = settings().getBoolean(["feature", "sendChecksumWithUnknownCommands"])
+		self._unknownCommandsNeedAck = settings().getBoolean(["feature", "unknownCommandsNeedAck"])
 		self._currentLine = 1
 		self._resendDelta = None
 		self._lastLines = deque([], 50)
@@ -1498,6 +1500,9 @@ class MachineCom(object):
 				# fetch command and optional linenumber from queue
 				command, linenumber, _ = entry
 
+				# some firmwares (e.g. Smoothie) might support additional in-band communication that will not
+				# stick to the acknowledgement behaviour of GCODE, so we check here if we have a GCODE command
+				# at hand here and only clear our clear_to_send flag later if that's the case
 				gcode_match = self._regex_command.search(command)
 				is_gcode = gcode_match is not None
 
@@ -1509,7 +1514,7 @@ class MachineCom(object):
 					# line number predetermined, use that
 					self._doSendWithChecksum(command, linenumber)
 				else:
-					if self.isPrinting() or self._alwaysSendChecksum:
+					if (is_gcode or self._sendChecksumWithUnknownCommands) and (self.isPrinting() or self._alwaysSendChecksum):
 						linenumber = self._currentLine
 						self._addToLastLines(command)
 						self._currentLine += 1
@@ -1517,12 +1522,17 @@ class MachineCom(object):
 					else:
 						self._doSendWithoutChecksum(command)
 
+				use_up_clear = not self._unknownCommandsNeedAck
 				if is_gcode:
-					# trigger "sent" phase
+					# trigger "sent" phase and use up one "ok"
 					self._process_command_phase("sent", command, gcode=gcode_match.group(1))
+					use_up_clear = True
+
+				# if we need to use up a clear, do that now
+				if use_up_clear:
+					self._clear_to_send.clear()
 
 				# wait for the next clear
-				self._clear_to_send.clear()
 				self._clear_to_send.wait()
 			except:
 				self._logger.exception("Caught an exception in the send loop")