bug#33684: DocView bombs out upon password protected PDFs

[Federico Tedin]

積丹尼 Dan Jacobson <jidanni@jidanni.org> writes:

> When trying to view a password protected PDF:
> DocView: process pdf/ps->png changed status to exited abnormally with code 1.
> Maybe it should ask for the password.
> emacs-version "25.2.2"

Would something like this make sense? A short patch that adds
`doc-view-pdf-password-protected-p', and an extra option to pass to
Ghostscript (-sPDFPassword=) when the command is invoked (only when the
PDF file is password protected). I tried it out by creating a
password-protected PDF using LibreOffice Writer, and then opening it
with find-file.

pdf-passwd.patch
Description: patch