file finalized functionality

[skidzo]

How can i find out if mdf4 file has been finalized? what is that reference to 'remove' here in that permalink? Am I confused? https://github.com/ratal/mdfreader/blob/6f5cbe685cc664532d79d524ad357cf7c8e1022f/mdfreader/mdfinfo4.py#L1220

[ratal]

Hi, Finalized file information is in IDBlock. For instance, if your id_file is not 'MDF' but 'UnFinMF', it is not finalised. Then flag in 'id_unf_flags' will tell you what to do to finalise the file (in mdfreader, print will appear). You can have more insight I think if you are investigating a suspicious file to open it with MDFValidator from Vector. the remove line 1220 is for specific implementation.: some people are actually embedding a mdf4 into a zip rather than using the already existing compression from spec. So to read this file, temporary uncompressed file is created. This line deals with it.

[skidzo]

Ok, Is that probably, what could achieve what I want?

import mdfreader

from mdfreader.mdf import _open_MDF

from mdfreader.mdfinfo4 import IDBlock, UINT16

class BlockInfo(IDBlock):

    def __init__(self):

        super(BlockInfo,self).__init__(fid=None)

    def isFinalized(self, fid):
        """ 
        reads IDBlock id_file
        """
        #self.read(fid)
        fid.seek(0)
        self['id_file'] = self.mdfblockreadCHAR(fid, 8)
        self['id_ver'] = self.mdfblockread(fid, UINT16, 1)
        fid.close()
        # treatment of unfinalised file
        if self['id_ver'] > 410 and 'UnFin' in self['id_file']:
            return False
        else:
            return True

if __name__ == "__main__":

        fid, _, _ = _open_MDF(fullFilePath)

        bi = BlockInfo()

        print(bi.isFinalized(fid))

At least this returns True, given that fullFilePath is pointing to a standard mdf file written by canape. Do you think I can listen with this on a file and wait for it is finalized and then call some event?

[ratal]

Hi, Yes, your code seems to be able to identify if a file is finalised. You could also cross check with flags 'id_unfi_flags'. However, I am not sure you can read your file while being written by canape under windows, you might have to investigate with OS module from python, maybe checking canape process activity...

[skidzo]

OK, i will have to really test this in a vitrualmachine first, i will let you know if I succeed or not. Could you indicate further how to use the 'id_unfi_flags' flags properly in my example?

[ratal]

You could directly use IDBlock from mdfinfo4, from line 211 temp=IDBlock(fid) temp will contain a dict with id_file and id_unfi_flags keys. And there, you can see there are prints to tell you what to expect according to each bit of id_unfi_flags.

[skidzo]

A quick test showed that it does not work this way using MDF4lib.dll 1.5.2.1, in the standard configuration of CANape 15, because it creates a tmp file which is locked for reading.