Bug#596793: python-apt: Add a lock argument to apt.Cache.update and apt.Cache.commit

[Sebastian Heinlein <devel@glatzor.de>]

Package: python-apt
Version: 0.7.97.1
Severity: wishlist

It would be nice to have a lock argument in the apt.cache.Cache.update()
and apt.cache.Cache.commit() methods.

It would allow to pass the fd (int) of an already acquired lock. The
corresponding methods won't try to get a lock on lists/archives if it's
given.

The packagekit backend and aptdaemon try to acquire the locks
before executing the tasks to give the user an idea which application
should be closed before the task can be performed, instead of failing
during the task.

So currently I have to acquire the locks at the start of a
transaction, release it again shortly before call e.g. Cache.update()
and re-aquire them again afterwards until the transaction is done.


-- System Information:
Debian Release: squeeze/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: i386 (i686)

Kernel: Linux 2.6.32-5-686 (SMP w/2 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages python-apt depends on:
ii  apt [libapt-pkg4.10]          0.8.4      Advanced front-end for dpkg
ii  apt-utils [libapt-inst1.2]    0.8.4      APT utility programs
ii  libc6                         2.11.2-5   Embedded GNU C Library: Shared lib
ii  libgcc1                       1:4.4.4-14 GCC support library
ii  libstdc++6                    4.4.4-14   The GNU Standard C++ Library v3
ii  python                        2.6.6-1    interactive high-level object-orie
ii  python-central                0.6.16     register and build utility for Pyt

Versions of packages python-apt recommends:
ii  iso-codes                     3.20-1     ISO language, territory, currency,
ii  lsb-release                   3.2-23.1   Linux Standard Base version report
ii  python2.6                     2.6.6-3    An interactive high-level object-o

Versions of packages python-apt suggests:
pn  python-apt-dbg                <none>     (no description available)
ii  python-apt-doc                0.7.97.1   Python interface to libapt-pkg (AP
ii  python-gtk2                   2.17.0-4   Python bindings for the GTK+ widge
ii  python-vte                    1:0.24.3-1 Python bindings for the VTE widget

-- no debconf information