mem: Add list len command

src/cmd/list.rs

@@ -7,19 +7,21 @@ use crate::cmd::parse::{ParseCommandError, Parser};
 
 #[derive(Debug, Clone)]
 pub enum ListCommand {
-    LGet(String),
-    LLen(String),
+    Len(String),
 }
 
 impl ListCommand {
     pub(super) fn parse(
         cmd_name: &str,
-        _parser: &Parser,
+        parser: &mut Parser,
     ) -> Result<Option<Command>, ParseCommandError> {
-        match cmd_name {
-            "lget" => todo!(),
-            "llen" => todo!(),
-            _ => Ok(None),
-        }
+        let list_cmd = match cmd_name {
+            "llen" => {
+                let key = parser.next_string()?;
+                Self::Len(key)
+            }
+            _ => return Ok(None),
+        };
+        Ok(Some(Command::List(list_cmd)))
     }
 }

src/cmd/parse.rs

@@ -52,7 +52,7 @@ impl TryFrom<Frame> for Command {
         // TODO(Shaohua): Add a command hash map.
         let mut command: Option<Self> = StringCommand::parse(&cmd_name, &mut parser)?;
         if command.is_none() {
-            command = ListCommand::parse(&cmd_name, &parser)?;
+            command = ListCommand::parse(&cmd_name, &mut parser)?;
         }
         if command.is_none() {
             log::warn!("Command not found: {cmd_name}");

src/mem/db.rs

@@ -6,6 +6,7 @@ use std::collections::HashMap;
 
 use crate::cmd::Command;
 use crate::cmd::frame::Frame;
+use crate::mem::list::ListObject;
 use crate::mem::Mem;
 use crate::mem::string::StrObject;
 
@@ -14,7 +15,7 @@ pub type Db = HashMap<String, MemObject>;
 #[derive(Debug, Clone)]
 pub enum MemObject {
     Str(StrObject),
-    List(String),
+    List(ListObject),
 }
 
 impl Mem {

src/mem/list/len.rs

@@ -0,0 +1,14 @@
+// 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 len(db: &Db, key: &str) -> Frame {
+    match db.get(key) {
+        Some(MemObject::List(list)) => Frame::Integer(list.len() as i64),
+        Some(_other) => Frame::wrong_type_err(),
+        None => Frame::null(),
+    }
+}

src/mem/list/mod.rs

@@ -2,13 +2,21 @@
 // Use of this source is governed by GNU Affero General Public License
 // that can be found in the LICENSE file.
 
+use std::collections::LinkedList;
+
 use crate::cmd::frame::Frame;
 use crate::cmd::list::ListCommand;
 use crate::mem::Mem;
 
+mod len;
+
+pub type ListObject = LinkedList<Vec<u8>>;
+
 impl Mem {
     #[allow(clippy::needless_pass_by_value)]
-    pub fn handle_list_command(&mut self, _command: ListCommand) -> Frame {
-        todo!()
+    pub fn handle_list_command(&mut self, command: ListCommand) -> Frame {
+        match command {
+            ListCommand::Len(key) => len::len(&self.db, &key),
+        }
     }
 }

src/mem/string/strlen.rs → src/mem/string/len.rs

@@ -6,7 +6,7 @@ use crate::cmd::frame::Frame;
 use crate::mem::db::{Db, MemObject};
 
 #[allow(clippy::cast_possible_wrap)]
-pub fn strlen(db: &Db, key: &str) -> Frame {
+pub fn len(db: &Db, key: &str) -> Frame {
     match db.get(key) {
         Some(MemObject::Str(value)) => Frame::Integer(value.len() as i64),
         Some(_other) => Frame::Error(

src/mem/string/mod.rs

@@ -11,7 +11,7 @@ use crate::mem::Mem;
 
 mod get;
 mod set;
-mod strlen;
+mod len;
 mod append;
 mod get_del;
 mod get_set;
@@ -86,7 +86,7 @@ impl Mem {
             StringCommand::GetSet(key, value) => get_set::get_set(&mut self.db, key, value),
             StringCommand::Set(key, value) => set::set(&mut self.db, key, value),
             StringCommand::SetRange(key, offset, value) => set_range::set_range(&mut self.db, key, offset, value),
-            StringCommand::StrLen(key) => strlen::strlen(&self.db, &key),
+            StringCommand::StrLen(key) => len::len(&self.db, &key),
             StringCommand::SubStr(key, start, end) => sub_str::sub_str(&self.db, &key, start, end),
         }
     }

src/mem/string/set_range.rs

@@ -28,10 +28,8 @@ pub fn set_range(db: &mut Db, key: String, offset: isize, value: Bytes) -> Frame
         let old_value = match old_value {
             MemObject::Str(s) => match s {
                 StrObject::Integer(_int) => todo!(),
-                StrObject::Vec(vec) => {
-                    vec
-                }
-            }
+                StrObject::Vec(vec) => vec,
+            },
             _ => return Frame::wrong_type_err(),
         };
         return if value.is_empty() {
@@ -40,6 +38,7 @@ pub fn set_range(db: &mut Db, key: String, offset: isize, value: Bytes) -> Frame
             if !check_string_length(offset_usize, value.len()) {
                 return FrameConst::from_str(STRING_TOO_LONG_ERR);
             }
+            // FIXME(Shaohua): merge two parts of vector
             old_value.put_slice(&value);
             Frame::Integer(old_value.len() as i64)
         };
@@ -58,4 +57,4 @@ pub fn set_range(db: &mut Db, key: String, offset: isize, value: Bytes) -> Frame
         db.insert(key, MemObject::Str(s));
         Frame::Integer(len as i64)
     }
-}
+}