Alaska Software Inc. - Problems with XbpMLE Insert() and PasteMarked()
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AuthorTopic: Problems with XbpMLE Insert() and PasteMarked()
Andreas Gehrs-Pahl
Problems with XbpMLE Insert() and PasteMarked()
on Tue, 29 Jun 2010 20:30:45 -0400
Dear Alaska Support Team,

The methods :Insert() and :PasteMarked() of the XbpMLE() class limit the 
amount of characters that can be inserted or pasted. The actual number
of characters that will be inserted or pasted apparently depends on the 
current size of the :EditBuffer(). If the :EditBuffer is empty, exactly 
30.000 characters can be inserted. After that, only an additional 4,096 
characters can be pasted at once into the object.

If XbpMLE():SetData() is used so that the :EditBuffer() already contains 
some text -- for example 50,000 characters -- the number of characters 
that can be pasted at once is limited by that :EditBuffer() size. It's
size can increase to only twice it's original size, which means in the
case of 50,000 characters, it can grow to 100,000 characters. This means
that only 50,000 additional characters can be pasted or inserted, unless
some of the existing characters in the :EditBuffer() are replaced. If all
characters are replaced, a maximum of 100,000 characters can be inserted
or pasted. Each consecutive insert or paste operation can increase the
size of the :EditBuffer() in the same way.

The :EditBuffer() and :SetData() methods have no such size limitations.

This problem can be fixed in a derived class by overloading the :Insert() 
and :PasteMarked() methods, to internally use the :EditBuffer() method 
instead. For some reason, specifying OVERRIDE for those methods doesn't 
seem to have an effect on the base class, though, as the default behavior 
of the XbpMLE() class can't be fully fixed this way. To completely fix it, 
the :Keyboard() method must also be overloaded to redirect the CTRL-V and 
Shift-Insert key events and a new pop-up menu must be added to replace the 
existing one, which contains a "Paste" option.

-- Andreas

---                                                                      ---
  Andreas Gehrs-Pahl              E-Mail: GPahl@CharterMI.net
  415 Gute Street                     or: Andreas@DDPSoftware.com
  Owosso, MI 48867-4410               or: Andreas_Gehrs-Pahl@CrimeCog.com
  Tel: (989) 723-9927           Web Site: http://www.Aerospace-History.net
---                                                                      ---
Andreas Gehrs-Pahl
Re: Problems with XbpMLE Insert() and PasteMarked()
on Wed, 30 Jun 2010 18:20:20 -0400
Dear Alaska Support Team,

I noticed that you created PDR 109-6305 for this issue. But I would have 
liked it better, if this PDR included all the issues raised. I also have 
to disagree with the "Solution" that was provided.

The only solution for the :PasteMarked() problem is to subclass the MLE,
including the :Keyboard() method and replacing the Popup Menu. And using 
the :SetData() method instead of :Insert() is not a good idea, as this 
has (usually undesirable) side effects, like executing the :DataLink 
code block. Instead, the :EditBuffer() method should be used. Not to 
mention that using either :SetData() or :EditBuffer() will require the
replacing of any marked text at the desired cursor position, and keeping
the existing, non-marked text, before and after the cursor position. So
it isn't that straight forward and simple as your "Use the :SetData() 
method instead of :Insert()" solution makes it look like.

Could you also elaborate on why the OVERRIDE clause has no effect on the 
XbpMLE class? Even with the :Insert() and :PasteMarked() methods replaced 
and marked as OVERRIDE, it still isn't possible to successfully Paste a
large text into a sub-classed MLE. I thought that the OVERRIDE clause was
designed to accomplish exactly that! Apparently the XbpMLE is using a
different method to accomplish the pasting of text from the clipboard. 
To me, this seems to be inconsistent with Xbase++ OOP principles.

Because the code of the XbpMLE():Keyboard() method and the code for the 
built-in Popup Menu's "Paste" option are not available to us, we should 
be able to rely on the fact that they internally call the :PasteMarked()
method, which in return should call the :Insert() method. If that isn't
the case, sub-classing and using OVERRIDE isn't very useful in the real
world.

-- Andreas

---                                                                      ---
  Andreas Gehrs-Pahl              E-Mail: GPahl@CharterMI.net
  415 Gute Street                     or: Andreas@DDPSoftware.com
  Owosso, MI 48867-4410               or: Andreas_Gehrs-Pahl@CrimeCog.com
  Tel: (989) 723-9927           Web Site: http://www.Aerospace-History.net
---                                                                      ---
Till WarwegRe: Problems with XbpMLE Insert() and PasteMarked()
on Thu, 01 Jul 2010 10:04:39 +0200
Hello Andreas,

> I noticed that you created PDR 109-6305 for this issue. But I would have
> liked it better, if this PDR included all the issues raised. I also have
> to disagree with the "Solution" that was provided.

  I'm aware the PDR doesn't reflect every issue you've raised in your
posting. I'm still working on it, which is also why I hadn't responded.

Please give me some time to work on this...

Best regards,
  Till Warweg
  [Alaska Software]

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--------------------------------------------------------------------



"Andreas Gehrs-Pahl" schrieb im Newsbeitrag 
news:pxv85c4lpqgy$.61gwpethksg4.dlg@40tude.net...
> Dear Alaska Support Team,
>
> I noticed that you created PDR 109-6305 for this issue. But I would have
> liked it better, if this PDR included all the issues raised. I also have
> to disagree with the "Solution" that was provided.
>
> The only solution for the :PasteMarked() problem is to subclass the MLE,
> including the :Keyboard() method and replacing the Popup Menu. And using
> the :SetData() method instead of :Insert() is not a good idea, as this
> has (usually undesirable) side effects, like executing the :DataLink
> code block. Instead, the :EditBuffer() method should be used. Not to
> mention that using either :SetData() or :EditBuffer() will require the
> replacing of any marked text at the desired cursor position, and keeping
> the existing, non-marked text, before and after the cursor position. So
> it isn't that straight forward and simple as your "Use the :SetData()
> method instead of :Insert()" solution makes it look like.
>
> Could you also elaborate on why the OVERRIDE clause has no effect on the
> XbpMLE class? Even with the :Insert() and :PasteMarked() methods replaced
> and marked as OVERRIDE, it still isn't possible to successfully Paste a
> large text into a sub-classed MLE. I thought that the OVERRIDE clause was
> designed to accomplish exactly that! Apparently the XbpMLE is using a
> different method to accomplish the pasting of text from the clipboard.
> To me, this seems to be inconsistent with Xbase++ OOP principles.
>
> Because the code of the XbpMLE():Keyboard() method and the code for the
> built-in Popup Menu's "Paste" option are not available to us, we should
> be able to rely on the fact that they internally call the :PasteMarked()
> method, which in return should call the :Insert() method. If that isn't
> the case, sub-classing and using OVERRIDE isn't very useful in the real
> world.
>
> -- Andreas
>
> ---                                                                      ---
>  Andreas Gehrs-Pahl              E-Mail: GPahl@CharterMI.net
>  415 Gute Street                     or: Andreas@DDPSoftware.com
>  Owosso, MI 48867-4410               or: Andreas_Gehrs-Pahl@CrimeCog.com
>  Tel: (989) 723-9927           Web Site: http://www.Aerospace-History.net
> ---                                                                      ---
Till WarwegRe: Problems with XbpMLE Insert() and PasteMarked()
on Fri, 02 Jul 2010 11:42:05 +0200
Hi Andreas et all,

  FYI: I've just updated PDR 6305 which describes the problem with :Insert() and
:PasteMarked() Andreas has reported.

It turns out the problem is due to an internal buffer limit of the edit control 
used
by the XbpMLE class. This buffer has to be increased to allow larger inserts or
pastes. This doesn't work right in the methods being discussed.

The easiest way to get around this probably is to use :SetData() to temporarily
increase the edit buffer. This can be done directly after the call to :Create().
Once the buffer was increased past the offending limit, subsequent calls to
:Insert() and :PasteMarked() should work as expected.

The following code snippet was copied from the "Solution" section in the PDR,
and illustrates this approach. Andreas, could you please check this out in your
original scenario?

The work-around Andreas suggested is valid too, of course!

#define WORK_AROUND_PDR6305
 Max. number of chararacters which can be
 inserted at once
#define MLE_MAXBUFFER_PDR6305  100000
(...)
oMLE := XbpMLE():New(...):Create(...)
#ifdef WORK_AROUND_PDR6305
WORKAROUND_PDR6305( oMLE )   (See below)
#endif
(...)

--
#ifdef WORK_AROUND_PDR6305
PROCEDURE WORKAROUND_PDR6305( oMLE )

  Temporarily extend edit buffer
  to have internal limits increased
  for later pastes and inserts
 oMLE:SetData( replicate(" ", MLE_MAXBUFFER_PDR6305) )
 oMLE:SetData("")

RETURN
#endif
Best regards,
  Till Warweg
  [Alaska Software]

PS. Andreas: there is the OVERRIDE issue still between us,
I know. I just wanted to reported findings on the MLDE
before delving into this one...

--------------------------------------------------------------------
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--------------------------------------------------------------------



"Till Warweg" schrieb im Newsbeitrag 
news:6a161904$258b05cd$292ff@news.alaska-software.com...
> Hello Andreas,
>
>> I noticed that you created PDR 109-6305 for this issue. But I would have
>> liked it better, if this PDR included all the issues raised. I also have
>> to disagree with the "Solution" that was provided.
>
>  I'm aware the PDR doesn't reflect every issue you've raised in your
> posting. I'm still working on it, which is also why I hadn't responded.
>
> Please give me some time to work on this...
>
> -- 
> Best regards,
>  Till Warweg
>  [Alaska Software]
>
> --------------------------------------------------------------------
> Technical Support:         support@alaska-software.com
> News Server:                 news.alaska-software.com
> Homepage:                     http://www.alaska-software.com
> KnowledgeBase:            http://www.alaska-software.com/kb
> --------------------------------------------------------------------
>
>
>
> "Andreas Gehrs-Pahl" schrieb im Newsbeitrag 
> news:pxv85c4lpqgy$.61gwpethksg4.dlg@40tude.net...
>> Dear Alaska Support Team,
>>
>> I noticed that you created PDR 109-6305 for this issue. But I would have
>> liked it better, if this PDR included all the issues raised. I also have
>> to disagree with the "Solution" that was provided.
>>
>> The only solution for the :PasteMarked() problem is to subclass the MLE,
>> including the :Keyboard() method and replacing the Popup Menu. And using
>> the :SetData() method instead of :Insert() is not a good idea, as this
>> has (usually undesirable) side effects, like executing the :DataLink
>> code block. Instead, the :EditBuffer() method should be used. Not to
>> mention that using either :SetData() or :EditBuffer() will require the
>> replacing of any marked text at the desired cursor position, and keeping
>> the existing, non-marked text, before and after the cursor position. So
>> it isn't that straight forward and simple as your "Use the :SetData()
>> method instead of :Insert()" solution makes it look like.
>>
>> Could you also elaborate on why the OVERRIDE clause has no effect on the
>> XbpMLE class? Even with the :Insert() and :PasteMarked() methods replaced
>> and marked as OVERRIDE, it still isn't possible to successfully Paste a
>> large text into a sub-classed MLE. I thought that the OVERRIDE clause was
>> designed to accomplish exactly that! Apparently the XbpMLE is using a
>> different method to accomplish the pasting of text from the clipboard.
>> To me, this seems to be inconsistent with Xbase++ OOP principles.
>>
>> Because the code of the XbpMLE():Keyboard() method and the code for the
>> built-in Popup Menu's "Paste" option are not available to us, we should
>> be able to rely on the fact that they internally call the :PasteMarked()
>> method, which in return should call the :Insert() method. If that isn't
>> the case, sub-classing and using OVERRIDE isn't very useful in the real
>> world.
>>
>> -- Andreas
>>
>> ---                                                                      ---
>>  Andreas Gehrs-Pahl              E-Mail: GPahl@CharterMI.net
>>  415 Gute Street                     or: Andreas@DDPSoftware.com
>>  Owosso, MI 48867-4410               or: Andreas_Gehrs-Pahl@CrimeCog.com
>>  Tel: (989) 723-9927           Web Site: http://www.Aerospace-History.net
>> ---                                                                      --- 
>
Till WarwegTOPIC SWITCH: OVERRIDE [was: Problems with XbpMLE Insert() and PasteMarked()]
on Fri, 02 Jul 2010 13:00:53 +0200
Hi again, Andreas.

Just to make sure I understand you correctly; as a work-around for
the problem with :Insert() and :PasteMarked(), you sub-classed 
XbpMLE and created your own (corrected) versions of  :Insert() 
and :PasteMarked(). 

The issue now is that even if the methods are declared as OVERRIDE,
your implementation isn't called in all cases. More specifically, 
what you expect is that choosing "Paste" from the MLE context 
menu should call :Insert() or :PasteMarked(), is that it?

If this is what the discussion is about (and not a problem with
OVERRIDE which I haven't yet grasped), the culprit probably
is in the fact that the context menu is opened by the edit control
itself. It's not ours. In other words, the control is kind of talking 
to itself when doing pastes. In this case, OVERRIDE has no effect
because XbpMLE is unaware of the proceedings.

Does this answer your question?

Best regards,
  Till Warweg
  [Alaska Software]

--------------------------------------------------------------------
Technical Support:         support@alaska-software.com
News Server:                 news.alaska-software.com
Homepage:                     http://www.alaska-software.com
KnowledgeBase:            http://www.alaska-software.com/kb
--------------------------------------------------------------------



"Andreas Gehrs-Pahl" schrieb im Newsbeitrag news:pxv85c4lpqgy$.61gwpethksg4.dlg@40tude.net...
> Dear Alaska Support Team,
> 
> I noticed that you created PDR 109-6305 for this issue. But I would have 
> liked it better, if this PDR included all the issues raised. I also have 
> to disagree with the "Solution" that was provided.
> 
> The only solution for the :PasteMarked() problem is to subclass the MLE,
> including the :Keyboard() method and replacing the Popup Menu. And using 
> the :SetData() method instead of :Insert() is not a good idea, as this 
> has (usually undesirable) side effects, like executing the :DataLink 
> code block. Instead, the :EditBuffer() method should be used. Not to 
> mention that using either :SetData() or :EditBuffer() will require the
> replacing of any marked text at the desired cursor position, and keeping
> the existing, non-marked text, before and after the cursor position. So
> it isn't that straight forward and simple as your "Use the :SetData() 
> method instead of :Insert()" solution makes it look like.
> 
> Could you also elaborate on why the OVERRIDE clause has no effect on the 
> XbpMLE class? Even with the :Insert() and :PasteMarked() methods replaced 
> and marked as OVERRIDE, it still isn't possible to successfully Paste a
> large text into a sub-classed MLE. I thought that the OVERRIDE clause was
> designed to accomplish exactly that! Apparently the XbpMLE is using a
> different method to accomplish the pasting of text from the clipboard. 
> To me, this seems to be inconsistent with Xbase++ OOP principles.
> 
> Because the code of the XbpMLE():Keyboard() method and the code for the 
> built-in Popup Menu's "Paste" option are not available to us, we should 
> be able to rely on the fact that they internally call the :PasteMarked()
> method, which in return should call the :Insert() method. If that isn't
> the case, sub-classing and using OVERRIDE isn't very useful in the real
> world.
> 
> -- Andreas
> 
> ---                                                                      ---
>  Andreas Gehrs-Pahl              E-Mail: GPahl@CharterMI.net
>  415 Gute Street                     or: Andreas@DDPSoftware.com
>  Owosso, MI 48867-4410               or: Andreas_Gehrs-Pahl@CrimeCog.com
>  Tel: (989) 723-9927           Web Site: http://www.Aerospace-History.net
> ---                                                                      ---