cluster: sort accepted view-change proposals

This makes it possible to search a MultiNodeCut by SocketAddr without
doing a linear scan.

Unfortunately, SocketAddr doesn't implement Ord, so we have to base the
sort on tuples of (ip, port).

related: rust-lang/rust#72239

src/cluster/cut.rs

@@ -12,6 +12,7 @@ use std::{
     collections::HashMap,
     convert::TryInto,
     net::SocketAddr,
+    ops::Index,
     result,
     sync::{Arc, Weak},
 };
@@ -89,6 +90,21 @@ pub struct MultiNodeCut {
     pub(crate) kicked: Arc<[Member]>,
 }
 
+impl Index<SocketAddr> for MultiNodeCut {
+    type Output = Member;
+
+    /// Binary search for the provided `addr`.
+    ///
+    /// O(log n)
+    ///
+    /// # Panics
+    /// Panics if a member with `addr` doesn't exist in the configuration.
+    #[inline]
+    fn index(&self, addr: SocketAddr) -> &Self::Output {
+        self.lookup(addr).unwrap()
+    }
+}
+
 impl MultiNodeCut {
     /// Returns the number of cuts that were skipped between this and the last received
     /// cut.
@@ -139,6 +155,18 @@ impl MultiNodeCut {
     pub fn kicked(&self) -> &Arc<[Member]> {
         &self.kicked
     }
+
+    /// Lookup a specific member in the configuration by socket address.
+    ///
+    /// Executes in O(log n) time.
+    pub fn lookup(&self, addr: SocketAddr) -> Option<&Member> {
+        let key = |s: SocketAddr| (s.ip(), s.port());
+
+        self.members
+            .binary_search_by_key(&key(addr), |m| key(m.addr()))
+            .ok()
+            .map(|i| &self.members[i])
+    }
 }
 
 /// A cluster member.

src/cluster/mod.rs

@@ -633,14 +633,21 @@ impl<St: partition::Strategy> Cluster<St> {
 
         let local_node = self.local_node();
 
+        joined.sort_by_key(|m| (m.addr().ip(), m.addr().port()));
+        kicked.sort_by_key(|m| (m.addr().ip(), m.addr().port()));
+
+        let mut members: Vec<_> = (state.nodes.iter())
+            .map(|node| self.resolve_member(state, node).unwrap())
+            .collect();
+
+        members.sort_by_key(|m| (m.addr().ip(), m.addr().port()));
+
         let cut = MultiNodeCut {
             skipped: 0,
             local_addr: self.addr,
             degraded: !state.nodes.contains(&local_node),
             conf_id: state.refresh_config(),
-            members: (state.nodes.iter())
-                .map(|node| self.resolve_member(state, node).unwrap())
-                .collect(),
+            members: members.into(),
             joined: joined.into(),
             kicked: kicked.into(),
         };

src/cluster/partition.rs

@@ -186,14 +186,20 @@ impl<St: Strategy> Cluster<St> {
             assert!(state.uuids.insert(uuid));
         }
 
+        joined.sort_by_key(|m| (m.addr().ip(), m.addr().port()));
+
+        let mut members: Vec<_> = (state.nodes.iter())
+            .map(|node| self.resolve_member(&state, node).unwrap())
+            .collect();
+
+        members.sort_by_key(|m| (m.addr().ip(), m.addr().port()));
+
         let cut = MultiNodeCut {
             skipped: 0,
             local_addr: self.addr,
             degraded: !state.nodes.contains(&self.local_node()),
             conf_id: state.refresh_config(),
-            members: (state.nodes.iter())
-                .map(|node| self.resolve_member(&state, node).unwrap())
-                .collect(),
+            members: members.into(),
             joined: joined.into(),
             kicked: vec![].into(),
         };