From b3a23a8d66d2f67c5e1a66f5ea1b45997ec06634 Mon Sep 17 00:00:00 2001
From: Steve Lau <stevelauc@outlook.com>
Date: Sat, 20 Jul 2024 09:05:39 +0800
Subject: [PATCH] refactor: simplify display impl & use the wrapper ty not the
 trait

---
 openraft/src/display_ext.rs                     |  2 +-
 .../display_ext/display_btreemap_opt_value.rs   | 17 ++++++-----------
 openraft/src/metrics/raft_metrics.rs            | 10 +++++-----
 3 files changed, 12 insertions(+), 17 deletions(-)

diff --git a/openraft/src/display_ext.rs b/openraft/src/display_ext.rs
index a03813a7c..aa3936f44 100644
--- a/openraft/src/display_ext.rs
+++ b/openraft/src/display_ext.rs
@@ -6,8 +6,8 @@ pub(crate) mod display_option;
 pub(crate) mod display_result;
 pub(crate) mod display_slice;
 
-#[allow(unused_imports)]
 pub(crate) use display_btreemap_opt_value::DisplayBTreeMapOptValue;
+#[allow(unused_imports)]
 pub(crate) use display_btreemap_opt_value::DisplayBtreeMapOptValueExt;
 #[allow(unused_imports)]
 pub(crate) use display_instant::DisplayInstant;
diff --git a/openraft/src/display_ext/display_btreemap_opt_value.rs b/openraft/src/display_ext/display_btreemap_opt_value.rs
index 0b00babaa..e7e353e5f 100644
--- a/openraft/src/display_ext/display_btreemap_opt_value.rs
+++ b/openraft/src/display_ext/display_btreemap_opt_value.rs
@@ -13,24 +13,19 @@ pub(crate) struct DisplayBTreeMapOptValue<'a, K: fmt::Display, V: fmt::Display>(
 
 impl<'a, K: fmt::Display, V: fmt::Display> fmt::Display for DisplayBTreeMapOptValue<'a, K, V> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        let opt_idx_of_last_one = self.0.len().checked_sub(1);
-
-        match opt_idx_of_last_one {
-            Some(idx_of_last_one) => {
-                for (idx, (key, value)) in self.0.iter().enumerate() {
-                    write!(f, "{}:{}", key, DisplayOption(value))?;
-                    if idx != idx_of_last_one {
-                        write!(f, ",")?;
-                    }
-                }
+        let len = self.0.len();
+        for (idx, (key, value)) in self.0.iter().enumerate() {
+            write!(f, "{}:{}", key, DisplayOption(value))?;
+            if idx + 1 != len {
+                write!(f, ",")?;
             }
-            None => { /* do nothing, as map length is 0 */ }
         }
 
         Ok(())
     }
 }
 
+#[allow(unused)]
 pub(crate) trait DisplayBtreeMapOptValueExt<'a, K: fmt::Display, V: fmt::Display> {
     fn display(&'a self) -> DisplayBTreeMapOptValue<'a, K, V>;
 }
diff --git a/openraft/src/metrics/raft_metrics.rs b/openraft/src/metrics/raft_metrics.rs
index 1d97be98c..1226fc07d 100644
--- a/openraft/src/metrics/raft_metrics.rs
+++ b/openraft/src/metrics/raft_metrics.rs
@@ -2,7 +2,7 @@ use std::fmt;
 use std::sync::Arc;
 
 use crate::core::ServerState;
-use crate::display_ext::DisplayBtreeMapOptValueExt;
+use crate::display_ext::DisplayBTreeMapOptValue;
 use crate::display_ext::DisplayOption;
 use crate::display_ext::DisplayOptionExt;
 use crate::error::Fatal;
@@ -116,8 +116,8 @@ where C: RaftTypeConfig
             self.membership_config,
             DisplayOption(&self.snapshot),
             DisplayOption(&self.purged),
-            DisplayOption(&self.replication.as_ref().map(DisplayBtreeMapOptValueExt::display)),
-            DisplayOption(&self.heartbeat.as_ref().map(DisplayBtreeMapOptValueExt::display)),
+            DisplayOption(&self.replication.as_ref().map(DisplayBTreeMapOptValue)),
+            DisplayOption(&self.heartbeat.as_ref().map(DisplayBTreeMapOptValue)),
         )?;
 
         write!(f, "}}")?;
@@ -200,8 +200,8 @@ where C: RaftTypeConfig
             DisplayOption(&self.snapshot),
             DisplayOption(&self.purged),
             self.millis_since_quorum_ack.display(),
-            DisplayOption(&self.replication.as_ref().map(DisplayBtreeMapOptValueExt::display)),
-            DisplayOption(&self.heartbeat.as_ref().map(DisplayBtreeMapOptValueExt::display)),
+            DisplayOption(&self.replication.as_ref().map(DisplayBTreeMapOptValue)),
+            DisplayOption(&self.heartbeat.as_ref().map(DisplayBTreeMapOptValue)),
         )?;
 
         write!(f, "}}")?;