Fix to stop xwinclip from clobbering remote clipboard

Fix to stop xwinclip from clobbering remote clipboard

[Øyvind Harboe]

I'm going out on a limb here, as my experience with xfree86 is extremely
limited. Perhaps there is an option to achieve what I'm suggesting here.

Oh well! :-)

xwinclip is clobbering the clipboard when I work w/e.g. OpenOffice:

- If I copy and paste a spreadsheet cell while xwinclip is running, only
the value is copied.
- If xwinclip is not running, I can copy and paste formulas without
problems.

AFAICT, xwinclip clobbers the remote clipboard by doing a "conversion
round-trip": remote clipboard->windows clipboard->remote clipboard. Such
round trip conversions are inheritely lossy and should be avoided.

After examining the source code(see below), I've come up with the
following "scheme" for a fix:

- register a new dummy windows clipboard data type, e.g. named
"REMOTEDATA".
- whenever xwinclip updates the Windows clipboard, it also invokes
SetClipboardData(REMOTEDATA, dummyval).
- whenever xwinclip executes a paste from the Windows clipboard to e.g.
an OpenOffice spreadsheet not running under Windows, xwinclip first
checks if REMOTEDATA is present in the Windows clipboard. If the flag is
present, xwinclip effectively needs to do nothing because the remote
clipboard already contains the correct data.


http://cvsweb.xfree86.org/cvsweb/xc/programs/Xserver/hw/xwin/winclipboardxevents.c


Øyvind

Re: Fix to stop xwinclip from clobbering remote clipboard

[Kensuke Matsuzaki]

Øyvind,

The reason why non-text clipboard contents is lost is not that.
To know windows clipboard change or not, you can use
SetClipboardViewer and WM_DRAWCLIPBOARD.

xwinclip clime CLIPBOARD ownership, but xwinclip can handle only XA_STRING,
UTF8_STRING and COMPOUND_TEXT.
xwinclip must hold all target to avoid clobbering X clipboard contents.

GNOME Clipboard Manager seems to do those well.
Perhaps their documents and code will help you.

By the way, latest code is here.
http://pdx.freedesktop.org/cgi-bin/viewcvs.cgi/xc/programs/Xserver/hw/xwin/winclipboardxevents.c?cvsroot=xorg&only_with_tag=CYGWIN&sortby=date

-- 
Kensuke Matsuzaki
mailto:zakki@peppermint.jp
http://peppermint.jp

Re: Fix to stop xwinclip from clobbering remote clipboard

[Harold L Hunt II]

Øyvind,

Øyvind Harboe wrote:

> I'm going out on a limb here, as my experience with xfree86 is extremely
> limited. Perhaps there is an option to achieve what I'm suggesting here.
> 
> Oh well! :-)
> 
> xwinclip is clobbering the clipboard when I work w/e.g. OpenOffice:
> 
> - If I copy and paste a spreadsheet cell while xwinclip is running, only
> the value is copied.
> - If xwinclip is not running, I can copy and paste formulas without
> problems.

Yes, that is a valid problem.

> AFAICT, xwinclip clobbers the remote clipboard by doing a "conversion
> round-trip": remote clipboard->windows clipboard->remote clipboard. Such
> round trip conversions are inheritely lossy and should be avoided.
> 
> After examining the source code(see below), I've come up with the
> following "scheme" for a fix:
> 
> - register a new dummy windows clipboard data type, e.g. named
> "REMOTEDATA".
> - whenever xwinclip updates the Windows clipboard, it also invokes
> SetClipboardData(REMOTEDATA, dummyval).
> - whenever xwinclip executes a paste from the Windows clipboard to e.g.
> an OpenOffice spreadsheet not running under Windows, xwinclip first
> checks if REMOTEDATA is present in the Windows clipboard. If the flag is
> present, xwinclip effectively needs to do nothing because the remote
> clipboard already contains the correct data.

No, that scheme does not work.

The problem is that we have to grab ownership of the X clipboard each 
time that either the X clipboard or the Windows clipboard changes.  So, 
we can't even attempt your idea because it requires that the original 
provider of the X clipboard data still be around when the request comes 
to paste that data; by grabbing ownership of the clipboard we tell that 
X app to dump the data to us in a single format.  This essentially means 
that OpenOffice no longer knows that it put in the clipboard; we have to 
tell it.

Your idea is part of what we will do when we use the XFIXES extension to 
monitor changes to the clipboard instead of stealing ownership of the 
clipboar each time another application changes it.  I wrote the code a 
while back to work with the XFIXES extension but it was never completely 
finished.  Maybe I will get to it soon.

Harold

Re: Fix to stop xwinclip from clobbering remote clipboard

[Hr. Daniel Mikkelsen]

On Tue, 23 Dec 2003, Øyvind Harboe wrote:

> I'm going out on a limb here, as my experience with xfree86 is extremely
> limited. Perhaps there is an option to achieve what I'm suggesting here.

Did you ever find out of that strange unicode-problem when copying from
OpenOffice? The "\x023" problem.

-- Daniel

Re: Fix to stop xwinclip from clobbering remote clipboard

[Harold L Hunt II]

Daniel,

Hr. Daniel Mikkelsen wrote:
> On Tue, 23 Dec 2003, Øyvind Harboe wrote:
> 
> 
>>I'm going out on a limb here, as my experience with xfree86 is extremely
>>limited. Perhaps there is an option to achieve what I'm suggesting here.
> 
> 
> Did you ever find out of that strange unicode-problem when copying from
> OpenOffice? The "\x023" problem.

If it was a problem due to the fact that the OpenOffice (X11, right) 
text got copied to Windows, then back to X11, then that should no longer 
be a problem in XFree86-xserv-4.3.0-31 since round-tripping has been 
eliminated.

Harold