Hi JS,
Your reading of the code is correct... the code will fail every time,
something I didn't catch as I haven't directly used this convenience
function in the p3d plugin or elsewhere.
Re-ordering the code so the input.readAllDataIntoBuffer() is done
before the if (!input) looks it would be appropriate. I've made this
change and checked it in, could you test it?
Robert.
On Wed, Jan 6, 2010 at 9:38 PM, Jean-Sébastien Guay
<jean-sebastien.g...@cm-labs.com> wrote:
> Hi Robert,
>
> I need to read an XML file and thought of using osgDB::XmlParser to do it.
> Calling this:
>
> osgDB::readXmlFile(filename);
>
> results in "Could not open XML file: somefilename.xml". But the file is
> there and some simple code using an ifstream to read the file (using the
> same filename variable) works. So I started looking into the code. One thing
> strikes me as weird in osgDB::readXmlFile() :
>
> // ...
> XmlNode::Input input;
> input.open(foundFile);
> if (!input)
> {
> // error "Could not open XML file: ... "
> }
>
> input.readAllDataIntoBuffer();
> // ...
>
> XmlNode::Input::Input() initializes _currentPos to 0. Then
> input.open(foundFile) calls ifstream::open(foundFile.c_str()) so up to
> there, all's well. But then XmlNode::Input::operator bool() is this:
>
> operator bool () const { return _currentPos<_buffer.size(); }
>
> Now, nothing has touched _buffer yet (readAllDataIntoBuffer() below the
> error is what fills it) so its size is 0, and _currentPos was set to 0 in
> the ctor, so this check ( _currentPos<_buffer.size(); ) will obviously
> return false.
>
> I don't think that's what is intended... is it? I don't see how this code
> could work at all, won't it error out every time?
>
> I searched for readXmlFile in the OSG sources and didn't get any results, is
> this used at all?
>
> A change that makes it work would be, for example:
>
> operator bool () const { return (_fin.good() && _currentPos == 0) ||
> _currentPos<_buffer.size(); }
>
> What's funny is that the XmlParser code is used in the present3D application
> (and I assume the p3d plugin too) but it doesn't use readXmlFile at all and
> just bypasses the check:
>
> osgDB::XmlNode::Input input;
> input.open(fileName);
> input.readAllDataIntoBuffer();
>
> Is this intended? Why would OSG not use its own helper function?
>
> ------------------
>
> Once I do this in my code (awaiting a good fix to readXmlFile() ), I get
> errors "end tag is not matched correctly" for items like:
>
> <item someattribute="somevalue" />
>
> This is valid XML syntax, but is it not supported by the XmlParser? I could
> add support for it, but it seems weird that it's not supported...
>
> Thanks,
>
> J-S
> --
> ______________________________________________________
> Jean-Sebastien Guay jean-sebastien.g...@cm-labs.com
> http://www.cm-labs.com/
> http://whitestar02.webhop.org/
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