Looking for help for clipboard in Math

[Regina Henschel]

Hi Michael,

and another report:

I found, what I did wrong. I had used GetTree() and not realized, that 
it does not only return a pointer but actually performs a "pop".
For text clipboard content I have followed your tip with SvMemoryStream 
and utl::OInputStreamWrapper.
So now I can import from clipboard, if the clipboard is of MIME type 
"application/mathml+xml" or if it is of type FORMAT_STRING and is 
actually a math-fragment.

But now I have this problem:
I start module Math with a fresh document, I write a formula into the 
command window (e.g. a^2+b^2) and then try to save as *.mml.
I get the errors cited below. I have not used any operations with the 
clipboard. A build from current trunk does not have this error, so it 
must be something, which I have introduced. But I do not know, what are 
possible causes and where to start.

Errormessages:

Locking problem.
Sharing violation while accessing the object.


Error: An error or a warning has occurred during XML import/export!
Error-Id: 0x60040004
     Flags: 6 ERRROR SEVERE
     Class: 4 API
     Number: 4
Parameters:
Exception-Message: io exception during writing
  From File 
c:/AOO_debugbuild_420/trunk/main/xmloff/source/core/xmlerror.cxx at Line 193

  Error: cached Sequence not written From File 
C:/AOO_debugbuild_420/trunk/main/sax/source/expatwrap/saxwriter.cxx at 
Line 164


Kind regards
Regina


Michael Stahl schrieb:
> On 06.06.2015 22:03, Regina Henschel wrote:
>> Hi Michael,
>>
>> thank-you for looking at my problems.
>>
>> Michael Stahl schrieb:
>>> On 05.06.2015 01:44, Regina Henschel wrote:
>>>> Hi all,
>>>>
>>>> I struggle with the clipboard. My goal is to import MathML in module
>>>> Math from clipboard, similar as it is imported from file. But I'm stuck.
>>>> Therefore some questions:
>> [skipped a lot of text]
>>
>> Helpful comments. Looking around I think, the connection to the OS is
>> done in /main/dtrans/source/win32/
>>
>> I have found the table m_TranslTable, which refers the SOT_FORMATSTR_IDs
>> from exchange.cxx. I'll try what happens, when I add the MathML format
>> there too. I had already added it in exchange.cxx, but that was not
>> enough to be recognized. [I need some time for that. I will report back,
>> when I have finished.]
>
> that sounds plausible.
>
>>>> (5)
>>>> I try to use SmViewShell::InsertFrom(SfxMedium &rMedium). It seems to
>>>> work, but when the process arrives at SmXMLImport::endDocument(void),
>>>> the node tree is empty.  Any tips, what I might have missed?
>>>
>>> how do you prepare the SfxMedium?  i'm not sure if it requires an actual
>>> file, or if it can read from an input stream (XInputStream); it probably
>>> can't read from a Sequence<sal_Int8> buffer directly...
>>>
>>> there is a SfxMedium::setStreamToLoadFrom() which looks promising.
>>
>> I have used:
>>
>> TransferableDataHelper aDataHelper(
>> TransferableDataHelper::CreateFromSystemClipboard(GetEditWindow()) );
>> uno::Reference < io::XInputStream > xStrm;
>> aDataHelper.GetInputStream( nId, xStrm );
>> SfxMedium* pClipboardMedium = new SfxMedium();
>> SfxMedium aClipboardMedium = *pClipboardMedium;
>
> this is probably not a good idea: the aClipboardMedium is now a copy of
> pClipboardMedium (using the copy-constructor), so any modification to
> aClipboardMedium will not be visible if you use pClipboardMedium.
>
> if you need a pointer, better do it the other way around, and use "&
> aClipbardMedium" when needed.
>
>> aClipboardMedium.setStreamToLoadFrom( xStrm, sal_True /*bIsReadOnly*/ );
>> InsertFrom(aClipboardMedium);
>
> oh, nice, the TransferableDataHelper can already get you a stream.
>
>> When I then proof it with
>>
>> SvStream* pStream = aClipboardMedium.GetInStream();
>> ...
>> sal_uLong nBytesRead = pStream->Read( aBuffer, nBufferSize );
>> printf("%s \n", aBuffer);
>>
>> I can see, that the stream contains the expected MathML-source in case
>> the clipboard viewer lists the clipboard format "application/mathml+xml".
>
> ok, so we can read the data.
>
> do you re-wind the stream with Seek() after this debug output?  perhaps
> the import filter reads from the current position, which is going to be
> in the middle or at the end of the stream after this.
>
>> In addition I have set the filter by
>>
>> const SfxFilter* pMathFilter = SfxFilter::GetFilterByName(
>> String::CreateFromAscii(MATHML_XML) );
>> aClipboardMedium.SetFilter(pMathFilter);
>>
>> so that
>>
>> if ( rFltName.EqualsAscii(MATHML_XML) )
>>
>> in InsertFrom becomes true
>
> it looks like SmXMLImportWrapper is using the usual xmloff XML-parsing
> stuff.
>
> so i would try to check if the root element of the MathML document is
> being recognized; set a breakpoint or add a SAL_DEBUG output in the
> right CreateChildContext() method...
>
> this is apparently SmXMLImport::CreateContext() - which should create a
> SmXMLDocContext_Impl, since there's not going to be a "office" namespace.
>
> most of the work is going on in the CreateChildContext() and
> EndElement() overrides in various child classes of SmXMLImportContext;
> basically xmloff maintains a stack of contexts, one for each currently
> open XML element; it then calls StartElement() / CreateChildContext() /
> EndElement() etc. on the context that is on top of the stack.
>
> this means it's quite annoying to step through the import with a
> debugger, since a lot of it is various abstraction layers that are not
> very interesting but you still have to step through them; it's best to
> set breakpoints in the "interesting" places and only start stepping into
> the lower layers as a last resort if you have no idea why the
> interesting place is not reached.
>
>>> you can create an input stream from the buffer via SvMemoryStream and
>>> then wrap that in utl::OInputStreamWrapper.
>>
>> You mean, it will be possible to use the "Unicode-Text"? That would
>> help, when copying from Websites. But first I need to solve the problem,
>> that I get no node-tree, and the problem to detect the clipboard correctly.
>
> no, i meant how to convert the clipboard Sequence<sal_Int8> to an input
> stream, but i missed that TransferableDataHelper::GetInputStream()
> already does this for you :)
>
>
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