HGKeeper

fix issue with sometimes wrong return code of ProcessLogger

2016-04-28, Andrey Skvortsov

d7f474d10210

fix issue with sometimes wrong return code of ProcessLogger

As a result of wrong return code Beremiz gives folowing traceback:
Traceback (most recent call last):
File "./Beremiz.py", line 850, in OnMenu
getattr(self.CTR, method)()
File "/home/developer/WorkData/PLC/beremiz/beremiz/ProjectController.py", line 925, in _Build
IECGenRes = self._Generate_SoftPLC()
File "/home/developer/WorkData/PLC/beremiz/beremiz/ProjectController.py", line 568, in _Generate_SoftPLC
return self._Compile_ST_to_SoftPLC()
File "/home/developer/WorkData/PLC/beremiz/beremiz/ProjectController.py", line 661, in _Compile_ST_to_SoftPLC
C_files.remove("POUS.c")
ValueError: list.remove(x): x not in list

The problem is that both threads (for reading stdout and stderr) call self.Proc.poll(),
that updates internal returncode field. This call is done without any locking and the first thread gets correct result,
but other gets 0 as retval. If 0 gets thread, that afterwards calls callback finish, then wrong return code is returned
to the parent. Now only the thread with a callback polls for the return code, other thread just checked local value.

Additionally function spin() waits now until all threads finish reading their pipes, so the results are always correct.

<?xml version="1.0" encoding="UTF-8" standalone="no"?>

</variables>

<![CDATA[

import cwiid,commands,sys,re,os,time

wiimote = None

WIIMOTE_ADDR_MODEL = re.compile("((?:[0-9A-F]{2})(?::[0-9A-F]{2}){5})\s*Nintendo")

nunchuckzero = None

def Wiimote_cback(messages, time):

global nunchuckzero

state = dict(messages)

bts = state.get(cwiid.MESG_BTN, None)

if bts is not None:

PLCGlobals.WiiButtons = bts

nunchuck = state.get(cwiid.MESG_NUNCHUK, None)

if nunchuck is not None:

PLCGlobals.WiiNunchuckButtons = nunchuck['buttons']

X,Y = nunchuck['stick']

PLCGlobals.WiiNunchuckAccX = nunchuck['acc'][cwiid.X]

PLCGlobals.WiiNunchuckAccY = nunchuck['acc'][cwiid.Y]

PLCGlobals.WiiNunchuckAccZ = nunchuck['acc'][cwiid.Z]

if nunchuckzero is None:

nunchuckzero = X,Y

(PLCGlobals.WiiNunchuckStickX,

PLCGlobals.WiiNunchuckStickY) = X-nunchuckzero[0],Y-nunchuckzero[1]

def Connect_Wiimote(connected_callback):

global wiimote,nunchuckzero

mac_addr = ''

try:

mac_addr = file("wiimac.txt","rt").read()

except:

PLCObject.LogMessage("Wiimote MAC unknown, scanning bluetooth")

output = commands.getoutput("hcitool scan")

result = WIIMOTE_ADDR_MODEL.search(output)

if result is not None:

mac_addr = result.group(1)

PLCObject.LogMessage("Found Wiimote with MAC %s"%mac_addr)

file("wiimac.txt","wt").write(mac_addr)

# Connect to wiimote

if not mac_addr:

PLCObject.LogMessage("Connection to unknown Wiimote...")

wiimote = cwiid.Wiimote()

else:

PLCObject.LogMessage("Connection to Wiimote %s..."%mac_addr)

wiimote = cwiid.Wiimote(mac_addr)

if wiimote is not None:

nunchuckzero = None

wiimote.rpt_mode = cwiid.RPT_BTN | cwiid.RPT_EXT

# use the callback interface

wiimote.mesg_callback = Wiimote_cback

wiimote.enable(cwiid.FLAG_MESG_IFC)

connected_callback(mac_addr)

PLCObject.LogMessage("Wiimote %s Connected"%mac_addr)

else:

PLCObject.LogMessage("Wiimote %s not found"%mac_addr)

os.remove("wiimac.txt")

connected_callback(None)

def Disconnect_Wiimote():

global wiimote

if wiimote is not None:

wiimote.disable(cwiid.FLAG_MESG_IFC)

time.sleep(0.1)

wiimote.close()

wiimote = None

PLCObject.LogMessage("Wiimote disconnected")

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</globals>

<init>

<![CDATA[

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</init>

<![CDATA[

Disconnect_Wiimote()

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</cleanup>

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</start>

<stop>

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</stop>

</PyFile>