Pavel - more on URL's

[Robert Collins]

You should also look at IOStreamProvider.h - this is how io stream
providers, which handle URL schemes register themselves. You can
leverage this to make the list of schemes pluggable (i.e. the
IOStreamProvider interface uses strings now, but should be converted to
URLScheme's etc). The current io_stream.cc code uses a pluggable list of
schemes, and I'd hope that that saves you a bit of coding (but where
list should sit is unclear. My feeling is that URLParser should be
unconcerned about known and unknown schemes but I'm not worried either
way).

Just ask if anything there is unclear).