From 2c0116bae2362221990f877280cdd504af66dd8e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=BC=A0=E7=82=8E=E6=B3=BC?= <drdr.xp@gmail.com>
Date: Fri, 24 Nov 2023 15:29:46 +0800
Subject: [PATCH] Refactor: replication/mod.rs

---
 openraft/src/replication/mod.rs | 65 +++++++++++++++++++++------------
 1 file changed, 42 insertions(+), 23 deletions(-)

diff --git a/openraft/src/replication/mod.rs b/openraft/src/replication/mod.rs
index 8cff1a062..c9cacf825 100644
--- a/openraft/src/replication/mod.rs
+++ b/openraft/src/replication/mod.rs
@@ -28,7 +28,9 @@ use crate::core::notify::Notify;
 use crate::display_ext::DisplayOption;
 use crate::display_ext::DisplayOptionExt;
 use crate::error::HigherVote;
+use crate::error::Infallible;
 use crate::error::RPCError;
+use crate::error::RaftError;
 use crate::error::ReplicationClosed;
 use crate::error::ReplicationError;
 use crate::error::Timeout;
@@ -231,29 +233,15 @@ where
                         ReplicationError::RPCError(err) => {
                             tracing::error!(err = display(&err), "RPCError");
 
-                            if let Some(request_id) = repl_id {
-                                let _ = self.tx_raft_core.send(Notify::Network {
-                                    response: Response::Progress {
-                                        target: self.target,
-                                        request_id,
-                                        result: Err(err.to_string()),
-                                        session_id: self.session_id,
-                                    },
-                                });
-                            } else {
-                                tracing::warn!(
-                                    err = display(&err),
-                                    "encountered RPCError but request_id is None, no response is sent"
-                                );
-                            }
-
                             // If there is an [`Unreachable`] error, we will backoff for a period of time
                             // Backoff will be reset if there is a successful RPC is sent.
-                            if let RPCError::Unreachable(_unreachable) = err {
+                            if let RPCError::Unreachable(_unreachable) = &err {
                                 if self.backoff.is_none() {
                                     self.backoff = Some(self.network.backoff());
                                 }
                             }
+
+                            self.send_progress_error(repl_id, err);
                         }
                     };
                 }
@@ -355,13 +343,13 @@ where
 
         match append_resp {
             AppendEntriesResponse::Success => {
-                self.update_matching(request_id, leader_time, log_id_range.last_log_id);
+                self.send_progress_matching(request_id, leader_time, log_id_range.last_log_id);
                 Ok(None)
             }
             AppendEntriesResponse::PartialSuccess(matching) => {
                 Self::debug_assert_partial_success(log_id_range, &matching);
 
-                self.update_matching(request_id, leader_time, matching);
+                self.send_progress_matching(request_id, leader_time, matching);
                 if matching < log_id_range.last_log_id {
                     // TODO(9): an RPC has already been made, it should use a newer time
                     Ok(Some(Data::new_logs(
@@ -391,14 +379,45 @@ where
                 debug_assert!(conflict.is_some(), "prev_log_id=None never conflict");
 
                 let conflict = conflict.unwrap();
-                self.update_conflicting(request_id, leader_time, conflict);
+                self.send_progress_conflicting(request_id, leader_time, conflict);
 
                 Ok(None)
             }
         }
     }
 
-    fn update_conflicting(&mut self, request_id: Option<u64>, leader_time: InstantOf<C>, conflict: LogId<C::NodeId>) {
+    /// Send the error result to RaftCore.
+    /// RaftCore will then submit another replication command.
+    fn send_progress_error(
+        &mut self,
+        request_id: Option<u64>,
+        err: RPCError<C::NodeId, C::Node, RaftError<C::NodeId, Infallible>>,
+    ) {
+        if let Some(request_id) = request_id {
+            let _ = self.tx_raft_core.send(Notify::Network {
+                response: Response::Progress {
+                    target: self.target,
+                    request_id,
+                    result: Err(err.to_string()),
+                    session_id: self.session_id,
+                },
+            });
+        } else {
+            tracing::warn!(
+                err = display(&err),
+                "encountered RPCError but request_id is None, no response is sent"
+            );
+        }
+    }
+
+    /// Send a `conflict` message to RaftCore.
+    /// RaftCore will then submit another replication command.
+    fn send_progress_conflicting(
+        &mut self,
+        request_id: Option<u64>,
+        leader_time: InstantOf<C>,
+        conflict: LogId<C::NodeId>,
+    ) {
         tracing::debug!(
             target = display(self.target),
             request_id = display(request_id.display()),
@@ -430,7 +449,7 @@ where
     /// Update the `matching` log id, which is for tracking follower replication, and report the
     /// matched log id to `RaftCore` to commit an entry.
     #[tracing::instrument(level = "trace", skip(self))]
-    fn update_matching(
+    fn send_progress_matching(
         &mut self,
         request_id: Option<u64>,
         leader_time: InstantOf<C>,
@@ -724,7 +743,7 @@ where
                 );
 
                 // TODO: update leader lease for every successfully sent chunk.
-                self.update_matching(request_id, leader_time, snapshot.meta.last_log_id);
+                self.send_progress_matching(request_id, leader_time, snapshot.meta.last_log_id);
 
                 return Ok(None);
             }