QCanDbcFileParse load error

SGaist

Hi and welcome to devnet,

You're using it wrong. That method expects a file path. Maybe you meant to use parseData ?

jsulm

@SGaist As far as I can see OP is passing a path to the file

jsulm

@dhagrow Why don't you do what the documentation suggests?
https://doc.qt.io/qt-6/qcandbcfileparser.html#parse
"If the parsing failed, call the error() and errorString() methods to get the information about the error."

JonB

@jsulm said in QCanDbcFileParse load error:

"If the parsing failed, call the error() and errorString() methods to get the information about the error."

OP already does!

if not parser.parse(dbc_file):
    sys.exit(f"QCanDbcFileParser.parse: {parser.errorString()}")
// Output:
QCanDbcFileParser.parse: No such file or directory

I think OP is asking: He shows QFile::open()ing the file correctly and shows its contents, so why does he get a "no such file or directory" from parser.parse(dbc_file) on same file path? I don't know.

@dhagrow
FWIW, bool QCanDbcFileParser::parse(const QString &fileName)

Note: This method expects the file contents to be encoded in UTF-8. If the file has a different encoding, decode it first, and use parseData() to extract the DBC information.

You might try passing your f.readAll()).decode() to bool QCanDbcFileParser::parseData(QStringView data) to see whether that succeeds? I do not know how that relates to a "no such file" failure from QCanDbcFileParser.parse().

jsulm

@JonB said in QCanDbcFileParse load error:

OP already does!

You're right, did not see that in the string formatting :-)

SGaist

@jsulm said in QCanDbcFileParse load error:

@SGaist As far as I can see OP is passing a path to the file

Indeed, I misread the reading/printing and parse call !

@dhagrow, @JonB has a point with regard to UTF-8.

Also, on which OS are you seeing this issue ?

JonB

@SGaist said in QCanDbcFileParse load error:

@dhagrow, @JonB has a point with regard to UTF-8.

Except that error "no such file or directory" does not sound like that, does sound like it's not finding the file. Or a strange message.

SGaist

@JonB said in QCanDbcFileParse load error:

@SGaist said in QCanDbcFileParse load error:

@dhagrow, @JonB has a point with regard to UTF-8.

Except that error "no such file or directory" does not sound like that, does sound like it's not finding the file. Or a strange message.

Indeed, I was just adding more weight with regard to using parseData which was related to my original question about it although it was mainly because I misread the code sample.

dhagrow

QCanDbcFileParser.parseData() does indeed work! Thanks for pointing that out, I hadn't noticed that method. I'm not sure why the encoding would matter. The contents are ASCII, which should be decoded by UTF-8 with no problem.

Nothing obvious strikes me from the source here, but I guess QString is not included in PySide, so I can't easily check.

It does seem like there should be a better error there, but this solves my immediate problem, and hopefully helps anyone else that runs into it. For the record, I'm on Linux. Thanks again!

JonB

@dhagrow
Yes, parseData() will work, the question is why parser.parse(dbc_file) does not seem to open the file from its name. Just try making dbc_file be the correct full path to the file (not just plain "dbc_file") and check whether that makes a difference?

dhagrow

I get this error instead when I pass in a full path, or even when I use any slash, e.g. ./test.dbc.

QCanDbcFileParser.parse: file to open is a directory

JonB

@dhagrow
Well that's very odd if it's a file and is reported as an open directory failure.
And also odd but maybe significant if the path alters message from "No such file or directory" to "file to open is a directory".