tdf#122239 Qt5 implement lazy clipboard handling

This changes the Qt5Clipboard to a lazy loading one, which will
just deliver data on read requests. This fixes not only the
PRIMARY selection problems with Writer, but will generally speed
up C'n'P, inside LO, because the data has not to be copied or
transferred via QMimeData.

This is mainly done by implementing the "mirror" interface of the
Qt5Transferable, the Qt5MimeData using the retrieveData override.

To prevent clipboard loss on shutdown, this sets a deep copied
QMimeData of the current XTransferable, to make it persistent.

This code explicitly doesn't use any of the QMimeData convenience
functions and relies completely on LO's string handling, so we
won't mix in eventual Qt bugs; all bugs are ours...

Change-Id: I43d92a95df8fcac88dc41b00021cea0b5f040413
Reviewed-on: https://gerrit.libreoffice.org/73288
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>

0 files changed, 0 insertions, 0 deletions