From 220c83e90a1b16e4320d8ec629f616d6affc05af Mon Sep 17 00:00:00 2001
From: "wangjie.wjdew" <wangjie.wjdew@bytedance.com>
Date: Thu, 17 Jul 2025 18:03:33 +0800
Subject: [PATCH 1/2] feat: support concat and add check for not adding empty
 bytes into list

---
 Cargo.toml |  2 +-
 src/lib.rs | 42 ++++++++++++++++++++++++++++++++----------
 2 files changed, 33 insertions(+), 11 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index bf3481c..4231c52 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "linkedbytes"
-version = "0.1.13"
+version = "0.1.14"
 authors = ["Volo Team <volo@cloudwego.io>"]
 edition = "2021"
 description = "LinkedBytes is a linked list of Bytes and BytesMut."
diff --git a/src/lib.rs b/src/lib.rs
index 6ee5d47..07a6c23 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -68,6 +68,20 @@ impl LinkedBytes {
         &mut self.bytes
     }
 
+    #[inline]
+    pub fn concat(&self) -> Bytes {
+        let list_len: usize = self.iter_list().map(|node| node.as_ref().len()).sum();
+        let total_len = list_len + self.bytes.len();
+        let mut dest = BytesMut::with_capacity(total_len);
+        for node in &self.list {
+            dest.put_slice(node.as_ref());
+        }
+        if !self.bytes.is_empty() {
+            dest.put_slice(&self.bytes);
+        }
+        dest.freeze()
+    }
+
     #[inline]
     pub fn reserve(&mut self, additional: usize) {
         self.bytes.reserve(additional);
@@ -87,20 +101,28 @@ impl LinkedBytes {
 
     pub fn insert(&mut self, bytes: Bytes) {
         let node = Node::Bytes(bytes);
-        // split current bytes
-        let prev = self.bytes.split();
-
-        self.list.push_back(Node::BytesMut(prev));
-        self.list.push_back(node);
+        if self.bytes.is_empty() {
+            self.list.push_back(node);
+        } else {
+            // split current bytes
+            let prev = self.bytes.split();
+
+            self.list.push_back(Node::BytesMut(prev));
+            self.list.push_back(node);
+        }
     }
 
     pub fn insert_faststr(&mut self, fast_str: FastStr) {
         let node = Node::FastStr(fast_str);
-        // split current bytes
-        let prev = self.bytes.split();
-
-        self.list.push_back(Node::BytesMut(prev));
-        self.list.push_back(node);
+        if self.bytes.is_empty() {
+            self.list.push_back(node);
+        } else {
+            // split current bytes
+            let prev = self.bytes.split();
+
+            self.list.push_back(Node::BytesMut(prev));
+            self.list.push_back(node);
+        }
     }
 
     pub fn io_slice(&self) -> Vec<IoSlice<'_>> {

From e500de60ea7c1434ab5d164a41825c0ea8a90ab8 Mon Sep 17 00:00:00 2001
From: "wangjie.wjdew" <wangjie.wjdew@bytedance.com>
Date: Tue, 22 Jul 2025 20:59:28 +0800
Subject: [PATCH 2/2] modify: return BytesMut for the concat api

---
 src/lib.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 07a6c23..9b44233 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -68,8 +68,9 @@ impl LinkedBytes {
         &mut self.bytes
     }
 
+    /// This concatenates the list and the bytes into a [`BytesMut`].
     #[inline]
-    pub fn concat(&self) -> Bytes {
+    pub fn concat(&self) -> BytesMut {
         let list_len: usize = self.iter_list().map(|node| node.as_ref().len()).sum();
         let total_len = list_len + self.bytes.len();
         let mut dest = BytesMut::with_capacity(total_len);
@@ -79,7 +80,7 @@ impl LinkedBytes {
         if !self.bytes.is_empty() {
             dest.put_slice(&self.bytes);
         }
-        dest.freeze()
+        dest
     }
 
     #[inline]