{-# LANGUAGE DeriveDataTypeable #-} {-# OPTIONS_HADDOCK hide #-} -- Some code in this file was adapted from the @network-conduit@ library by -- Michael Snoyman. Copyright (c) 2011. See its licensing terms (BSD3) at: -- https://github.com/snoyberg/conduit/blob/master/network-conduit/LICENSE module Network.Simple.Internal ( HostPreference(..) , hpHostName ) where import Data.String (IsString (fromString)) import qualified Network.Socket as NS -- | Preferred host to bind. data HostPreference = HostAny -- ^Any available host. | HostIPv4 -- ^Any available IPv4 host. | HostIPv6 -- ^Any available IPv6 host. | Host NS.HostName -- ^An explicit host name. deriving (Eq, Ord, Show, Read) -- | The following special values are recognized: -- -- * @*@ means 'HostAny' -- -- * @*4@ means 'HostIPv4' -- -- * @*6@ means 'HostIPv6' -- -- * Any other string is 'Host' instance IsString HostPreference where fromString "*" = HostAny fromString "*4" = HostIPv4 fromString "*6" = HostIPv6 fromString s = Host s -- | Extract the 'NS.HostName' from a 'Host' preference, or 'Nothing' otherwise. hpHostName:: HostPreference -> Maybe NS.HostName hpHostName (Host s) = Just s hpHostName _ = Nothing