This commit doesn't add any feature and just fixes a small annoyance which
result in messages like this:
Checking if xxx applies...no.
See that there is no whitespace between "..." and "no"? Well, the world cares
for more important things, but for me personally those minor annoyances can turn
into major annoyances.
Until this commit we had a single hash of the whole version response from
omahaproxy. This worked well for not updating unnecessarily but only until one
single channel has a new version available.
Unfortunately the dev version is released quite frequently, so the hash is of no
use at all (we could rather directly fetch everything everytime we execute the
script).
This led to this commit, which adds two methods of caching:
First of all, if a perticular version/channel is already in the previous version
of the sources.nix file, don't download it again.
And the second method is to check if the current sha256 is already downloaded
and reads the corresponding sha256 from the lookup table.
So, this should really help to avoid flooding the download servers and to not
stress impatient users too much.
The previos update script just used the last version of chromium that showed up
at the bucket list at:
http://commondatastorage.googleapis.com/chromium-browser-official/
I'm not sure which channel this list actually holds, so I'm going to switch now
using the official release channels grabbed by omahaproxy. This also has the
advantage that we can provide different versions/flavors of chromium.
We now also write our data to sources.nix instead of source.nix, as we have more
than one source.
It fetches the latest version based on the bucketlist XML from
commondatastorage and generates a "source.nix" which contains an attribute set
about where to fetch the latest version.
The XML is parsed in a somewhat hackish way using sed, but as this is just an
updater, its okay and we don't want to break a fly on the wheel by employing a
full XML parser.
