POULibrary.py
author Andrey Skvortsov <andrej.skvortzov@gmail.com>
Thu, 28 Apr 2016 13:05:57 +0300
changeset 1507 d7f474d10210
parent 772 98786137232d
child 1511 91538d0c242c
permissions -rw-r--r--
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.
from weakref import ref

class POULibrary:
    def __init__(self, CTR, LibName, TypeStack):
        from PLCControler import PLCControler
        self.CTR = ref(CTR)
        self.LibName = LibName
        self.LibraryControler = PLCControler()
        self.LibraryControler.OpenXMLFile(self.GetLibraryPath())
        self.LibraryControler.ClearConfNodeTypes()
        self.LibraryControler.AddConfNodeTypesList(TypeStack)
        self.program = None;

    def GetSTCode(self):
        if not self.program:
            self.program = self.LibraryControler.GenerateProgram()[0]+"\n"
        return self.program 

    def GetName(self):
        return self.LibName

    def GetCTR(self):
        return self.CTR()
        
    def GetTypes(self):
        return {"name" : self.GetName(), "types": self.LibraryControler.Project}

    def GetLibraryPath(self):
        raise Exception("Not implemented")

    def Generate_C(self, buildpath, varlist, IECCFLAGS):
        # Pure python or IEC libs doesn't produce C code
        return ((""), [], False), ""