beremiz

Dirty fix for error '_object_has_no_attribute_'getSlave' in EtherCAT extension

2018-08-10, Andrey Skvortsov
a3ac46366b86
Dirty 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


this is looks like dirty hack to fix strange problem with initial[0]
changing its type after returning from _init_ method to lxml.etree._Element
As a result all methods generated by class factory are lost.

For example, in function initMethod initial[0].__class__ points to
xmlclass.xmlclass.Config. After map(self.append, initial)
self.Config.__class__ is 'xmlclass.xmlclass.Config' as well.
But after returning from initMethod (_init) in CreateElement
self.Config.__class__ has changed to lxml.etree._Element.


I've noticed similar behavior if copy/deepcopy is used for any child
of etree.ElementBase. See simple example below.
[-------------------------------------------------------------]
#!/usr/bin/python

from __future__ import print_function
from lxml import etree
import copy

class DefaultElementClass(etree.ElementBase):
def getLocalTag(self):
return etree.QName(self.tag).localname


def printInformation(x):
print(x, x.__class__, "getLocalTag" in dir(x))


a = DefaultElementClass()
printInformation(a)

#
printInformation(copy.copy(a))
printInformation(copy.deepcopy(a))
[-------------------------------------------------------------]
#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# See COPYING.Runtime file for copyrights details.
#
from __future__ import absolute_import
import ctypes
from ctypes import *
from datetime import timedelta as td
ctypes.pythonapi.PyString_AsString.argtypes = (ctypes.c_void_p,)
ctypes.pythonapi.PyString_AsString.restype = ctypes.POINTER(ctypes.c_char)
class IEC_STRING(Structure):
"""
Must be changed according to changes in iec_types.h
"""
_fields_ = [("len", c_uint8),
("body", c_char * 126)]
class IEC_TIME(Structure):
"""
Must be changed according to changes in iec_types.h
"""
_fields_ = [("s", c_long), # tv_sec
("ns", c_long)] # tv_nsec
def _t(t, u=lambda x: x.value, p=lambda t, x: t(x)):
return (t, u, p)
def _ttime():
return (IEC_TIME,
lambda x: td(0, x.s, x.ns/1000.0),
lambda t, x: t(x.days * 24 * 3600 + x.seconds, x.microseconds*1000))
SameEndianessTypeTranslator = {
"BOOL": _t(c_uint8, lambda x: x.value != 0),
"STEP": _t(c_uint8),
"TRANSITION": _t(c_uint8),
"ACTION": _t(c_uint8),
"SINT": _t(c_int8),
"USINT": _t(c_uint8),
"BYTE": _t(c_uint8),
"STRING": (IEC_STRING,
lambda x: x.body[:x.len],
lambda t, x: t(len(x), x)),
"INT": _t(c_int16),
"UINT": _t(c_uint16),
"WORD": _t(c_uint16),
"DINT": _t(c_int32),
"UDINT": _t(c_uint32),
"DWORD": _t(c_uint32),
"LINT": _t(c_int64),
"ULINT": _t(c_uint64),
"LWORD": _t(c_uint64),
"REAL": _t(c_float),
"LREAL": _t(c_double),
"TIME": _ttime(),
"TOD": _ttime(),
"DATE": _ttime(),
"DT": _ttime(),
}
SwapedEndianessTypeTranslator = {
# TODO
}
TypeTranslator = SameEndianessTypeTranslator
# Construct debugger natively supported types
DebugTypesSize = dict([(key, sizeof(t)) for key, (t, p, u) in SameEndianessTypeTranslator.iteritems() if t is not None])
def UnpackDebugBuffer(buff, indexes):
res = []
buffoffset = 0
buffsize = len(buff)
buffptr = cast(ctypes.pythonapi.PyString_AsString(id(buff)), c_void_p).value
for iectype in indexes:
c_type, unpack_func, _pack_func = \
TypeTranslator.get(iectype, (None, None, None))
if c_type is not None and buffoffset < buffsize:
cursor = c_void_p(buffptr + buffoffset)
value = unpack_func(cast(cursor,
POINTER(c_type)).contents)
buffoffset += sizeof(c_type) if iectype != "STRING" else len(value)+1
res.append(value)
else:
break
if buffoffset and buffoffset == buffsize:
return res
return None