From 5e3590410168c473f7fccc26f299e21d44c57bbe Mon Sep 17 00:00:00 2001
From: "Tobin C. Harding" <tobin@coblox.tech>
Date: Wed, 28 Oct 2020 08:38:10 +1100
Subject: [PATCH] Use an option for the local port

We can wrap the local port in an option and pass None when we are not using Tor.
This reduces code duplication.
---
 swap/src/alice.rs | 69 +++++++++++------------------------------------
 swap/src/main.rs  |  4 +--
 2 files changed, 18 insertions(+), 55 deletions(-)

diff --git a/swap/src/alice.rs b/swap/src/alice.rs
index 72a05b76..bbaf00ac 100644
--- a/swap/src/alice.rs
+++ b/swap/src/alice.rs
@@ -1,6 +1,6 @@
 //! Run an XMR/BTC swap in the role of Alice.
 //! Alice holds XMR and wishes receive BTC.
-use anyhow::Result;
+use anyhow::{bail, Result};
 use libp2p::{
     core::{identity::Keypair, Multiaddr},
     request_response::ResponseChannel,
@@ -28,35 +28,13 @@ use xmr_btc::{alice::State0, bob, monero};
 
 pub type Swarm = libp2p::Swarm<Alice>;
 
-#[cfg(not(feature = "tor"))]
 pub async fn swap(
     listen: Multiaddr,
+    local_port: Option<u16>,
     redeem_address: ::bitcoin::Address,
     punish_address: ::bitcoin::Address,
 ) -> Result<()> {
-    let swarm = new_swarm(listen)?;
-    _swap(redeem_address, punish_address, swarm).await
-}
-#[cfg(feature = "tor")]
-pub async fn swap(
-    listen: Multiaddr,
-    local_port: u16,
-    redeem_address: ::bitcoin::Address,
-    punish_address: ::bitcoin::Address,
-) -> Result<()> {
-    let swarm = new_swarm(listen, local_port)?;
-    _swap(redeem_address, punish_address, swarm).await
-}
-
-// TODO: After we have done some testing replace all the 'panic's with log
-// statements or error returns.
-
-// FIXME: This whole function is horrible, needs total re-write.
-async fn _swap(
-    redeem_address: ::bitcoin::Address,
-    punish_address: ::bitcoin::Address,
-    mut swarm: Swarm,
-) -> Result<()> {
+    let mut swarm = new_swarm(listen, local_port)?;
     let message0: bob::Message0;
     let mut last_amounts: Option<SwapAmounts> = None;
 
@@ -129,8 +107,7 @@ async fn _swap(
     Ok(())
 }
 
-#[cfg(feature = "tor")]
-fn new_swarm(listen: Multiaddr, port: u16) -> Result<Swarm> {
+fn new_swarm(listen: Multiaddr, port: Option<u16>) -> Result<Swarm> {
     use anyhow::Context as _;
 
     let behaviour = Alice::default();
@@ -138,7 +115,18 @@ fn new_swarm(listen: Multiaddr, port: u16) -> Result<Swarm> {
     let local_key_pair = behaviour.identity();
     let local_peer_id = behaviour.peer_id();
 
-    let transport = transport::build(local_key_pair, Some((listen.clone(), port)))?;
+    let transport;
+    #[cfg(feature = "tor")]
+    {
+        transport = match port {
+            Some(port) => transport::build(local_key_pair, Some((listen.clone(), port)))?,
+            None => bail!("Must supply local port"),
+        };
+    }
+    #[cfg(not(feature = "tor"))]
+    {
+        transport = transport::build(local_key_pair)?;
+    }
 
     let mut swarm = libp2p::swarm::SwarmBuilder::new(transport, behaviour, local_peer_id.clone())
         .executor(Box::new(TokioExecutor {
@@ -154,31 +142,6 @@ fn new_swarm(listen: Multiaddr, port: u16) -> Result<Swarm> {
     Ok(swarm)
 }
 
-#[cfg(not(feature = "tor"))]
-fn new_swarm(listen: Multiaddr) -> Result<Swarm> {
-    use anyhow::Context as _;
-
-    let behaviour = Alice::default();
-
-    let local_key_pair = behaviour.identity();
-    let local_peer_id = behaviour.peer_id();
-
-    let transport = transport::build(local_key_pair)?;
-
-    let mut swarm = libp2p::swarm::SwarmBuilder::new(transport, behaviour, local_peer_id.clone())
-        .executor(Box::new(TokioExecutor {
-            handle: tokio::runtime::Handle::current(),
-        }))
-        .build();
-
-    Swarm::listen_on(&mut swarm, listen.clone())
-        .with_context(|| format!("Address is not supported: {:#}", listen))?;
-
-    info!("Initialized swarm: {}", local_peer_id);
-
-    Ok(swarm)
-}
-
 #[allow(clippy::large_enum_variant)]
 #[derive(Debug)]
 pub enum OutEvent {
diff --git a/swap/src/main.rs b/swap/src/main.rs
index 76a05526..a6d830e6 100644
--- a/swap/src/main.rs
+++ b/swap/src/main.rs
@@ -143,11 +143,11 @@ async fn swap_as_alice(
 ) -> Result<()> {
     #[cfg(not(feature = "tor"))]
     {
-        alice::swap(addr, redeem, punish).await
+        alice::swap(addr, None, redeem, punish).await
     }
     #[cfg(feature = "tor")]
     {
-        alice::swap(addr, PORT, redeem, punish).await
+        alice::swap(addr, Some(PORT), redeem, punish).await
     }
 }