Add ChannelPhase::is_funded for filtering channels.

Exposing ChannelPhase in ChannelManager has led to verbose match
statements, which need to be modified each time a ChannelPhase is added.
Making ChannelPhase an implementation detail of Channel would help avoid
this.

As a step in this direction, introduce ChannelPhase::is_funded for use
in ChannelManager when a Channel (to be later renamed FundedChannel)
needs to be tested for.

Author: jkczyz

lightning/src/ln/channel.rs

@@ -1153,6 +1153,10 @@ impl<'a, SP: Deref> ChannelPhase<SP> where
 		}
 	}
 
+	pub fn is_funded(&self) -> bool {
+		self.as_funded().is_some()
+	}
+
 	pub fn as_funded(&self) -> Option<&Channel<SP>> {
 		if let ChannelPhase::Funded(channel) = self {
 			Some(channel)

lightning/src/ln/channelmanager.rs

@@ -1366,13 +1366,7 @@ impl <SP: Deref> PeerState<SP> where SP::Target: SignerProvider {
 				return false;
 			}
 		}
-		!self.channel_by_id.iter().any(|(_, phase)|
-			match phase {
-				ChannelPhase::Funded(_) | ChannelPhase::UnfundedOutboundV1(_) => true,
-				ChannelPhase::UnfundedInboundV1(_) => false,
-				ChannelPhase::UnfundedV2(chan) => chan.context.is_outbound(),
-			}
-		)
+		!self.channel_by_id.iter().any(|(_, channel)| channel.is_funded() || channel.context().is_outbound())
 			&& self.monitor_update_blocked_actions.is_empty()
 			&& self.closed_channel_monitor_update_ids.is_empty()
 	}