Currently SfxObjectShell::CheckIsReadonly() has a hack for the LOK case
to show the signatures dialog read-only, as only that is async.
The next step is to make DocumentDigitalSignatures::ImplViewSignatures()
async, though that requires all callers of the function to be async, so
make DocumentDigitalSignatures::signScriptingContent() async as well.
There is also DocumentDigitalSignatures::signPackage(), but turns out
that's dead code, so just remove it.
Once this is in place, we had a problem that the callbacks tried to
interact with libxmlsec, but the dialog was still alive in
DocumentDigitalSignatures::ImplViewSignatures() by the time the callback
was running, so there were two DocumentSignatureManager instances at the
same time, and both assumes it should call the global libxmlsec
init/uninit, which resulted in failing to verify the just created
signature.
Fix this similar to how Tomaz fixed the same problem around pdfium in
commit 067a8a954c (pdfium: only init
pdfium library one and destroy on LO exit, 2020-06-03).
Change-Id: I3fb63c06195564732e1576dbd755157e676fb762
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/173117
Tested-by: Jenkins
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
