[packagekit] Python GTK widgets and async client

[Sebastian Heinlein]

Hello,

I hacked on the PyGTK widgets recently. I run into the problem that I
need a lot more async data than what the progress callback of the
current client could provide. E.g. I would like to show reported
packages immediately in the TreeView or show the status of a transaction
as soon at it gets started.

* Async methods

So I added the PackageKitTransaction class to packagekit.client. If a
client method is called with the async=True parameter the method will
return a PackageKitTransaction instance which was not yet started
instead of the results.

PackageKitTransaction now does all the signal wrapping and holds a
reference to the DBus interface of the corresponding transaction. This
allows me to hook the widgets to a transaction before running it. The
transaction can be started by calling run(). The run method also has got
a wait parameter, which allows to still run the transaction
synchronously. So I am not sure if the naming of the async parameter is
correct. :)

Do you agree with this approach? Is there a better name for the
parameter async? Should I use different methods instead: e.b.
SearchNameAsync?

I haven't converted all client methods to the new API since I wanted to
wait for feedback.

* PyGTK widgets

I introduced the python modules genums and widgets which are shipped in
gnome-packagekit. The first one is an automatically created python
version of gpk-enum.c. The later one contains the following widgets:

* PackageKitCancelButton

* PackageKitStatusIcon

* PackageKitStatusAnimation

* PackageKitStatusLabel

* PackageKitProgressBar: The run method also runs the associated
transaction.

* PackageKitMessageDialog

* PackageListStore :An enhanced gtk.ListStore which holds the
corresponding PackageKitPackage instances of Package signals which have
been emitted by a transaction.

* PackageListView: Renders the content of the above PackageListStore.

Except of the PackageListView all widgets are connected to a transaction
by using the transaction parameter with a PackageKitTransaction instance
at creation time or the set_transaction method afterwards.

Here is a code example how to refresh the cache, show the progress in a
dialog and handle errors in an error dialog:

pk = PackageKitClient()
trans = pk.RefreshCache(async=True)
dialog = PackageKitProgressDialog(transaction=trans, parent=win)
try:
    dialog.run()
except PackageKitError, e:
    msg = PackageKitMessageDialog(enum=e.error, details=e.desc,
                                  parent=win)
    msg.run()
    msg.hide()
dialog.hide()

The widgets module provides a fully working test application, which can
search, refresh, get updates, install and remove packages.

You can find the code in the async-client branch of PackageKit and the
python-widgets branch of gnome-packagekit. The branches are some days
behind master.

Cheers,

Sebastian