This doesn't quite work, because canceling a transfer sends a signal
to git-annex, but not to rsync (etc).
Looked at making git-annex run in its own process group, which could then
be killed, and would kill child processes. But, rsync checks if it's
process group is the foreground process group and doesn't show progress if
not, and when git has run git-annex, if git-annex makes a new process
group, that is not the case. Also, if git has run git-annex, ctrl-c
wouldn't be propigated to it if it made a new process group.
So this seems like a blind alley, but recording it here just in case.
Now an alert tracks files that have recently been added. As a large file
is added, it will have its own alert, that then combines with the tracker
when dones.
Also used for combining sanity checker alerts, as it could possibly want to
display a lot.
This allows me to not build-depend on blaze-markup, which was causing
me some trouble when tring to build with cabal on debian. Seems debian
ships Text.Blaze.Renderer.String in two packages.
Now the javascript does an ajax call at the start to request the url
to use to poll, and the notification id is generated then, once we know
javascript is working.
Depending on how the webapp was started up and whether the user clicked on
any links in it, window.close() may be disallowed by browser security
policy. Also if that fails, display a modal dialog that nicely blackens out
the webapp.
TODO: avoid Escape closing it. Bootstrap's docs are unclear about how to do
that.
Putting the transfer on the currentTransfers atomically introduced a bug:
It checks to see if the transfer is in progress, and cancels it.
Fixed by moving that check inside the STM transaction.
This may be customised differently than the main page later on, but
for now the important thing is that this constantly refreshed page does not
allocate a new NotificationHandle each time it's loaded.
WebApp now shows changes with no delay. Comparing a running git-annex get
and the webapp side-by-side, they both show each new transfer at the same
time.