Fwd: Re: [GSOC] Using cached formula results during ODS import

[Daniel Bankston]

Sorry, I meant to also CC Kohei and mailing list.

>>  I having trouble trying to think of a way to prevent ScFormulaCells from
>>  being set dirty without my hackish ScDocument libreoffice-generated-doc
>>  flag.
>>
>>  During the import of the functions.ods unit test file, ScFormulaCells are
>>  set dirty at three different times in three different ways.
>>
>>  1) ScMyTables::SetMatrix() uses a call chain down to
>>  ScFormulaCell::SetMatColsRows() which sets the ScFormulaCell dirty.
>  This one might be legitimate. We need to check if we can also import
>  the cached values of matrix formulas.
In my first attempted implementation, I prevented the formula cells from
being set dirty in this case, and the cached values still worked.  So I
think I just need to change the way ScMyTables::SetMatrix() works to
avoid setting cells dirty.

>>  2) ScDocument::CompileXML() uses a SetDirty call chain.
>>  3) ScDocShell::AfterXMLLoading() eventually calls ScFormulaCell::Notify
>>  which sets the ScFormulaCell to dirty.
>  As discussed on IRC we can change these two to follow the design we
>  discussed. CompileXML and AfterXMLLoading are only called when we load
>  the document and can therefore follow the new concept with the hard
>  recalculation at the end. We may need to think a bit about the
>  SetDocumentModified behavior and think about good ways to call the
>  correct update methods without setting the formula cells dirty but I
>      hink this is possible and cleaner than manipulating directly
>  ScFormulaCell.
Yes, CompileXML is no problem.  Yes, I'll have to do more in-depth
thought about SetDocumentModified behavior.
>>  I MAY be able to do something about 1; I'm not sure yet.
>>  I can probably stop 2 from setting dirty since it is only used in import.
>>  I don't see anyway to change 3 since ScFormulaCell::Notify() is so widely
>>  used.
>>
>>  Backtraces for 1, 2, and 3 are attached.
>>
>>  I know Markus said we are trying to get away from flags like ScDocument's
>>  IsImportingXML, but if I slightly modify the order of things in
>>  ScDocShell::AfterXMLLoading(), I think I can check if IsImportingXML is set
>>  to stop ScFormulaCell::SetDirty() from actually setting the cell dirty.
>>  That would solve 1, 2, and 3, and it would prevent me from adding my own
>>  ScDocument libreoffice-generated-doc flag.
>>
>  We don't even like adding new callers to IsImportingXML if not really
>  necessary. We should first check if there is not really a cleaner and
>  simpler solution to prevent these calls during import before we add
>  such a check deep down in the formula part of calc.
I guess I was too tempted by the quick fix.  ;-)  I'll think a lot
harder about this and see what I can come up with.