beremiz

Proper fix for error 'object has no attribute 'getSlave' in EtherCAT extension

2018-08-24, Andrey Skvortsov
96ca6b056c55
file isExecutable
Proper fix for error 'object has no attribute 'getSlave' in EtherCAT extension

traceback:
File "/home/developer/WorkData/PLC/beremiz/beremiz/IDEFrame.py", line 1433, in OnPouSelectedChanged
window.RefreshView()
File "/home/developer/WorkData/PLC/beremiz/beremiz/etherlab/ConfigEditor.py", line 837, in RefreshView
self.RefreshProcessVariables()
File "/home/developer/WorkData/PLC/beremiz/beremiz/etherlab/ConfigEditor.py", line 886, in RefreshProcessVariables
slaves = self.Controler.GetSlaves(**self.CurrentNodesFilter)
File "/home/developer/WorkData/PLC/beremiz/beremiz/etherlab/EthercatMaster.py", line 341, in GetSlaves
for slave in self.Config.getConfig().getSlave():
:_'lxml.etree._Element'_object_has_no_attribute_'getSlave'

Steps to reproduce problem:

- Add new EtherCAT master
- Add new EthercatNode to the master
- double click on


Revert commit "Dirty fix for error '_object_has_no_attribute_'getSlave' in EtherCAT extension"
[a3ac46366b86a0b237dac93be6b2281ac70b98a8].

The problem was that XML elements (proxy object) in some cases were created using custom XML
classes constructors and lxml.etree.Element() call and live python
patching. This causes that lxml backend doesn't know that custom python class
should be used for these XML elements.
Proxy object can be move/deleted and recreated by lxml
backend at any point in time or this can be done in python by copy/deepcopy operations.
If this happens, then newly created
proxy elements are using default class lxml.etree._Element. And all
custom functionality is lost.

All created XML elements should be always created through corresponding
parser and class lookup callback done by lxml backend.
It's described in more details in lxml documentation:
https://lxml.de/element_classes.html
#!/usr/bin/env python
# -*- coding: utf-8 -*-
# This file is part of Beremiz, a Integrated Development Environment for
# programming IEC 61131-3 automates supporting plcopen standard and CanFestival.
#
# Copyright (C) 2007: Edouard TISSERANT and Laurent BESSARD
#
# See COPYING file for copyrights details.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
from __future__ import absolute_import
import os
import re
import operator
import hashlib
from util.ProcessLogger import ProcessLogger
includes_re = re.compile('\s*#include\s*["<]([^">]*)[">].*')
class toolchain_makefile(object):
def __init__(self, CTRInstance):
self.CTRInstance = CTRInstance
self.md5key = None
self.buildpath = None
self.SetBuildPath(self.CTRInstance._getBuildPath())
def SetBuildPath(self, buildpath):
if self.buildpath != buildpath:
self.buildpath = buildpath
self.md5key = None
def GetBinaryCode(self):
return None
def _GetMD5FileName(self):
return os.path.join(self.buildpath, "lastbuildPLC.md5")
def ResetBinaryCodeMD5(self):
self.md5key = None
try:
os.remove(self._GetMD5FileName())
except Exception:
pass
def GetBinaryCodeMD5(self):
if self.md5key is not None:
return self.md5key
else:
try:
return open(self._GetMD5FileName(), "r").read()
except IOError:
return None
def concat_deps(self, bn):
# read source
src = open(os.path.join(self.buildpath, bn), "r").read()
# update direct dependencies
deps = []
for l in src.splitlines():
res = includes_re.match(l)
if res is not None:
depfn = res.groups()[0]
if os.path.exists(os.path.join(self.buildpath, depfn)):
# print bn + " depends on "+depfn
deps.append(depfn)
# recurse through deps
# TODO detect cicular deps.
return reduce(operator.concat, map(self.concat_deps, deps), src)
def build(self):
srcfiles = []
cflags = []
wholesrcdata = ""
for _Location, CFilesAndCFLAGS, _DoCalls in self.CTRInstance.LocationCFilesAndCFLAGS:
# Get CFiles list to give it to makefile
for CFile, CFLAGS in CFilesAndCFLAGS:
CFileName = os.path.basename(CFile)
wholesrcdata += self.concat_deps(CFileName)
srcfiles.append(CFileName)
if CFLAGS not in cflags:
cflags.append(CFLAGS)
oldmd5 = self.md5key
self.md5key = hashlib.md5(wholesrcdata).hexdigest()
# Store new PLC filename based on md5 key
f = open(self._GetMD5FileName(), "w")
f.write(self.md5key)
f.close()
if oldmd5 != self.md5key:
target = self.CTRInstance.GetTarget().getcontent()
beremizcommand = {"src": ' '.join(srcfiles),
"cflags": ' '.join(cflags),
"md5": self.md5key,
"buildpath": self.buildpath}
# clean sequence of multiple whitespaces
cmd = re.sub(r"[ ]+", " ", target.getCommand().strip())
command = [token % beremizcommand for token in cmd.split(' ')]
# Call Makefile to build PLC code and link it with target specific code
status, _result, _err_result = ProcessLogger(self.CTRInstance.logger,
command).spin()
if status:
self.md5key = None
self.CTRInstance.logger.write_error(_("C compilation failed.\n"))
return False
return True
else:
self.CTRInstance.logger.write(_("Source didn't change, no build.\n"))
return True