targets/plc_main_head.c
author Andrey Skvortsov <andrej.skvortzov@gmail.com>
Fri, 24 Aug 2018 13:41:43 +0300
changeset 2297 96ca6b056c55
parent 1981 d0718654d9b0
child 2503 6ffeffb6d635
permissions -rw-r--r--
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():
<type 'exceptions.AttributeError'>:_'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
/**
 * Head of code common to all C targets
 **/

#include "beremiz.h"
#include <string.h>
/*
 * Prototypes of functions provided by generated C softPLC
 **/
void config_run__(unsigned long tick);
void config_init__(void);

/*
 * Prototypes of functions provided by generated target C code
 * */
long long AtomicCompareExchange64(long long*, long long, long long);
void __init_debug(void);
void __cleanup_debug(void);
/*void __retrieve_debug(void);*/
void __publish_debug(void);

/*
 *  Variables used by generated C softPLC and plugins
 **/
IEC_TIME __CURRENT_TIME;
IEC_BOOL __DEBUG = 0;
unsigned long __tick = 0;
char *PLC_ID = NULL;

/*
 *  Variable generated by C softPLC and plugins
 **/
extern unsigned long greatest_tick_count__;

/* Help to quit cleanly when init fail at a certain level */
static int init_level = 0;

/* Prototype for Logging to help spotting errors at init */
int LogMessage(uint8_t level, char* buf, uint32_t size);

/*
 * Prototypes of functions exported by plugins
 **/
%(calls_prototypes)s

/*
 * Retrieve input variables, run PLC and publish output variables
 **/
void __run(void)
{
    __tick++;
    if (greatest_tick_count__)
        __tick %%= greatest_tick_count__;

    %(retrieve_calls)s

    /*__retrieve_debug();*/

    config_run__(__tick);

    __publish_debug();

    %(publish_calls)s

}

/*
 * Initialize variables according to PLC's default values,
 * and then init plugins with that values
 **/
int __init(int argc,char **argv)
{
    int res = 0;
    init_level = 0;
    
    /* Effective tick time with 1ms default value */
    if(!common_ticktime__)
        common_ticktime__ = 1000000;

    config_init__();
    __init_debug();
    %(init_calls)s
    return res;
}
/*
 * Calls plugin cleanup proc.
 **/
void __cleanup(void)
{
    %(cleanup_calls)s
    __cleanup_debug();
}

void PLC_GetTime(IEC_TIME *CURRENT_TIME);
void PLC_SetTimer(unsigned long long next, unsigned long long period);