Merge pull request #712 from kakaroto/master

Add a wrapper around pySerial to monkey patch support for custom baudrates

printrun/printcore.py

@@ -17,7 +17,7 @@
 
 __version__ = "2015.03.10"
 
-from serial import Serial, SerialException, PARITY_ODD, PARITY_NONE
+from serialWrapper import Serial, SerialException, PARITY_ODD, PARITY_NONE
 from select import error as SelectError
 import threading
 from Queue import Queue, Empty as QueueEmpty

printrun/serialWrapper.py

@@ -0,0 +1,49 @@
+# Serial wrapper around pyserial that adds support for custom baudrates (250000)
+# on linux, when pyserial is < 2.7
+
+# This code was copied from the pyserial 2.7 base code.
+# Therefore, it follows the license used by pyserial which is the '3-clause BSD license'
+
+from serial import *
+import sys
+
+if sys.platform.startswith('linux'):
+	import serial.serialposix
+
+	try:
+		import pkg_resources
+
+		old_version = float(pkg_resources.get_distribution("pyserial").version) < 2.7
+	except:
+		old_version = True
+
+	if old_version and not hasattr(serial.serialposix, "TCGETS2") and \
+	   hasattr(serial.serialposix, "set_special_baudrate"):
+		# Detected pyserial < 2.7 which doesn't support custom baudrates
+		# Replacing set_special_baudrate with updated function from pyserial 2.7
+
+		TCGETS2 = 0x802C542A
+		TCSETS2 = 0x402C542B
+		BOTHER = 0o010000
+
+		def set_special_baudrate(port, baudrate):
+			# right size is 44 on x86_64, allow for some growth
+			import array
+			buf = array.array('i', [0] * 64)
+
+			try:
+				# get serial_struct
+				FCNTL.ioctl(port.fd, TCGETS2, buf)
+				# set custom speed
+				buf[2] &= ~TERMIOS.CBAUD
+				buf[2] |= BOTHER
+				buf[9] = buf[10] = baudrate
+
+				# set serial_struct
+				res = FCNTL.ioctl(port.fd, TCSETS2, buf)
+			except IOError, e:
+				raise ValueError('Failed to set custom baud rate (%s): %s' % (baudrate, e))
+
+		# We need to change the function inside the serialposix module otherwise, it won't
+		# be called by the code within that module
+		serial.serialposix.set_special_baudrate = set_special_baudrate