string: Add get-del command

src/cmd/string.rs

@@ -11,6 +11,7 @@ use crate::cmd::parse::{Parser, ParsingCommandError};
 pub enum StringCommand {
     Append(String, Bytes),
     Get(String),
+    GetDel(String),
     Set(String, Bytes),
     StrLen(String),
 }
@@ -30,6 +31,10 @@ impl StringCommand {
                 let key = parser.next_string()?;
                 Self::Get(key)
             }
+            "getdel" => {
+                let key = parser.next_string()?;
+                Self::GetDel(key)
+            }
             "set" => {
                 let key = parser.next_string()?;
                 let value = parser.next_bytes()?;

src/mem/string/append.rs

@@ -2,6 +2,8 @@
 // Use of this source is governed by GNU Affero General Public License
 // that can be found in the LICENSE file.
 
+#![allow(clippy::cast_possible_wrap)]
+
 use std::collections::hash_map::Entry;
 
 use bytes::Bytes;
@@ -19,7 +21,7 @@ pub fn append(db: &mut Db, key: String, value: Bytes) -> Frame {
     match db.entry(key) {
         Entry::Occupied(mut occupied) => match occupied.get_mut() {
             MemObject::Str(old_str) => {
-                old_str.append(value);
+                old_str.append(&value);
                 let len = old_str.len();
                 Frame::Integer(len as i64)
             }

src/mem/string/get_del.rs

@@ -0,0 +1,18 @@
+// Copyright (c) 2024 Xu Shaohua <[email protected]>. All rights reserved.
+// Use of this source is governed by GNU Affero General Public License
+// that can be found in the LICENSE file.
+
+use crate::cmd::frame::Frame;
+use crate::mem::db::{Db, MemObject};
+
+pub fn get_del(db: &mut Db, key: &String) -> Frame {
+    match db.get(key) {
+        Some(MemObject::Str(value)) => {
+            let frame = Frame::Bulk(value.to_bytes());
+            db.remove(key);
+            frame
+        }
+        Some(_other) => Frame::wrong_type_err(),
+        None => Frame::null(),
+    }
+}

src/mem/string/mod.rs

@@ -12,6 +12,7 @@ mod get;
 mod set;
 mod strlen;
 mod append;
+mod get_del;
 
 #[derive(Debug, Clone)]
 pub enum StrObject {
@@ -22,14 +23,15 @@ pub enum StrObject {
 impl StrObject {
     #[must_use]
     #[inline]
+    #[allow(clippy::needless_pass_by_value)]
     pub fn from_bytes(bytes: Bytes) -> Self {
         Self::Vec(bytes.to_vec())
     }
 
-    pub fn append(&mut self, bytes: Bytes) {
+    pub fn append(&mut self, bytes: &Bytes) {
         match self {
-            StrObject::Integer(_integer) => todo!(),
-            StrObject::Vec(vec) => {
+            Self::Integer(_integer) => todo!(),
+            Self::Vec(vec) => {
                 let mut bytes_vec = bytes.to_vec();
                 vec.append(&mut bytes_vec);
             }
@@ -38,9 +40,9 @@ impl StrObject {
 
     pub fn to_bytes(&self) -> Bytes {
         match self {
-            StrObject::Integer(_integer) => todo!(),
-            StrObject::Vec(vec) => {
-                Bytes::copy_from_slice(&vec)
+            Self::Integer(_integer) => todo!(),
+            Self::Vec(vec) => {
+                Bytes::copy_from_slice(vec)
             }
         }
     }
@@ -56,8 +58,8 @@ impl StrObject {
     pub fn len(&self) -> usize {
         match self {
             // TODO(Shaohua):
-            StrObject::Integer(_) => 8,
-            StrObject::Vec(vec) => vec.len(),
+            Self::Integer(_) => 8,
+            Self::Vec(vec) => vec.len(),
         }
     }
 }
@@ -67,6 +69,7 @@ impl Mem {
         match command {
             StringCommand::Append(key, value) => append::append(&mut self.db, key, value),
             StringCommand::Get(key) => get::get(&self.db, &key),
+            StringCommand::GetDel(key) => get_del::get_del(&mut self.db, &key),
             StringCommand::Set(key, value) => set::set(&mut self.db, key, value),
             StringCommand::StrLen(key) => strlen::strlen(&self.db, &key),
         }