recoverable downloads - opinions sought

["Robert Collins" <robert dot collins at itdomain dot com dot au>]

To do recoverable downloads we need 2 things.
1) A way to check the file, other than filesize, for integrity. MD5 will
do and IIRC that's already caclulated on sources.redhat.
2) Code to pickup partway through and carry on.

For 2) we can either code it internally, or link statically to something
like libcurl, or call out to wget/curl.

Thoughts/opinions?

My current mental state:
For creating a mirror aka download only, we have to run on a cygwin-free
system with little or no loss of functionality. Imagine someone on a
corporate network with a dedicated 'net' PC, and cygwin not allowed on
that.

Using an external helper, via a bootstrap process will be a lot easier,
but will sacrifice the functionality when on a non-cygwin machine.

So I'm in favour of internal code/static library linkage. A dynamic
library _could_ be used, but we'd ned to treat it as a special case, not
as a standard isntall-and-log package.

The alternative to internal/static code is to go down the path of
splitting setup into two builds, but as we'd _still_ have to get the
download-without-cygwin part right, I see no benefit in this.

Anything I've missed/got wrong?

Rob