Serves the asset at the path in
req for generator_name via res.
# File lib/rdoc/servlet.rb, line 92
def asset generator_name, req, res
asset_dir = @asset_dirs[generator_name]
asset_path = File.join asset_dir, req.path
if_modified_since req, res, asset_path
res.body = File.read asset_path
res.content_type = case req.path
when /css$/ then 'text/css'
when /js$/ then 'application/javascript'
else 'application/octet-stream'
end
end