258 lines
9.0 KiB
Rust
258 lines
9.0 KiB
Rust
use core::str;
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use std::collections::HashMap;
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use std::sync::Arc;
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use tokio::io::AsyncReadExt;
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use tokio::io::AsyncWriteExt;
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use tokio::sync::{Mutex, oneshot};
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use std::sync::atomic::{AtomicU64, Ordering};
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use crate::cmd::Cmd;
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use crate::error::DBError;
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use crate::options;
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use crate::protocol::Protocol;
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use crate::storage_trait::StorageBackend;
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use crate::admin_meta;
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#[derive(Clone)]
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pub struct Server {
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pub db_cache: std::sync::Arc<std::sync::RwLock<HashMap<u64, Arc<dyn StorageBackend>>>>,
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pub option: options::DBOption,
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pub client_name: Option<String>,
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pub selected_db: u64, // Changed from usize to u64
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pub queued_cmd: Option<Vec<(Cmd, Protocol)>>,
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pub current_permissions: Option<crate::rpc::Permissions>,
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// BLPOP waiter registry: per (db_index, key) FIFO of waiters
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pub list_waiters: Arc<Mutex<HashMap<u64, HashMap<String, Vec<Waiter>>>>>,
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pub waiter_seq: Arc<AtomicU64>,
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}
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pub struct Waiter {
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pub id: u64,
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pub side: PopSide,
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pub tx: oneshot::Sender<(String, String)>, // (key, element)
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}
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#[derive(Clone, Copy, Debug, PartialEq, Eq)]
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pub enum PopSide {
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Left,
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Right,
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}
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impl Server {
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pub async fn new(option: options::DBOption) -> Self {
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Server {
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db_cache: Arc::new(std::sync::RwLock::new(HashMap::new())),
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option,
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client_name: None,
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selected_db: 0,
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queued_cmd: None,
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current_permissions: None,
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list_waiters: Arc::new(Mutex::new(HashMap::new())),
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waiter_seq: Arc::new(AtomicU64::new(1)),
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}
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}
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pub fn current_storage(&self) -> Result<Arc<dyn StorageBackend>, DBError> {
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let mut cache = self.db_cache.write().unwrap();
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if let Some(storage) = cache.get(&self.selected_db) {
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return Ok(storage.clone());
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}
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// Use process-wide shared handles to avoid sled/reDB double-open lock contention.
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let storage = if self.selected_db == 0 {
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// Admin DB 0: always via singleton
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admin_meta::open_admin_storage(
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&self.option.dir,
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self.option.backend.clone(),
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&self.option.admin_secret,
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)?
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} else {
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// Data DBs: via global registry keyed by id
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admin_meta::open_data_storage(
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&self.option.dir,
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self.option.backend.clone(),
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&self.option.admin_secret,
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self.selected_db,
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)?
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};
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cache.insert(self.selected_db, storage.clone());
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Ok(storage)
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}
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/// Check if current permissions allow read operations
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pub fn has_read_permission(&self) -> bool {
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matches!(self.current_permissions, Some(crate::rpc::Permissions::Read) | Some(crate::rpc::Permissions::ReadWrite))
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}
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/// Check if current permissions allow write operations
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pub fn has_write_permission(&self) -> bool {
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matches!(self.current_permissions, Some(crate::rpc::Permissions::ReadWrite))
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}
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// ----- BLPOP waiter helpers -----
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pub async fn register_waiter(&self, db_index: u64, key: &str, side: PopSide) -> (u64, oneshot::Receiver<(String, String)>) {
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let id = self.waiter_seq.fetch_add(1, Ordering::Relaxed);
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let (tx, rx) = oneshot::channel::<(String, String)>();
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let mut guard = self.list_waiters.lock().await;
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let per_db = guard.entry(db_index).or_insert_with(HashMap::new);
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let q = per_db.entry(key.to_string()).or_insert_with(Vec::new);
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q.push(Waiter { id, side, tx });
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(id, rx)
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}
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pub async fn unregister_waiter(&self, db_index: u64, key: &str, id: u64) {
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let mut guard = self.list_waiters.lock().await;
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if let Some(per_db) = guard.get_mut(&db_index) {
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if let Some(q) = per_db.get_mut(key) {
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q.retain(|w| w.id != id);
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if q.is_empty() {
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per_db.remove(key);
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}
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}
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if per_db.is_empty() {
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guard.remove(&db_index);
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}
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}
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}
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// Called after LPUSH/RPUSH to deliver to blocked BLPOP waiters.
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pub async fn drain_waiters_after_push(&self, key: &str) -> Result<(), DBError> {
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let db_index = self.selected_db;
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loop {
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// Check if any waiter exists
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let maybe_waiter = {
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let mut guard = self.list_waiters.lock().await;
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if let Some(per_db) = guard.get_mut(&db_index) {
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if let Some(q) = per_db.get_mut(key) {
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if !q.is_empty() {
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// Pop FIFO
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Some(q.remove(0))
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} else {
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None
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}
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} else {
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None
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}
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} else {
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None
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}
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};
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let waiter = if let Some(w) = maybe_waiter { w } else { break };
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// Pop one element depending on waiter side
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let elems = match waiter.side {
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PopSide::Left => self.current_storage()?.lpop(key, 1)?,
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PopSide::Right => self.current_storage()?.rpop(key, 1)?,
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};
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if elems.is_empty() {
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// Nothing to deliver; re-register waiter at the front to preserve order
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let mut guard = self.list_waiters.lock().await;
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let per_db = guard.entry(db_index).or_insert_with(HashMap::new);
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let q = per_db.entry(key.to_string()).or_insert_with(Vec::new);
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q.insert(0, waiter);
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break;
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} else {
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let elem = elems[0].clone();
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// Send to waiter; if receiver dropped, just continue
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let _ = waiter.tx.send((key.to_string(), elem));
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// Loop to try to satisfy more waiters if more elements remain
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continue;
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}
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}
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Ok(())
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}
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pub async fn handle(
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&mut self,
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mut stream: tokio::net::TcpStream,
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) -> Result<(), DBError> {
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// Accumulate incoming bytes to handle partial RESP frames
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let mut acc = String::new();
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let mut buf = vec![0u8; 8192];
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loop {
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let n = match stream.read(&mut buf).await {
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Ok(0) => {
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println!("[handle] connection closed");
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return Ok(());
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}
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Ok(n) => n,
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Err(e) => {
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println!("[handle] read error: {:?}", e);
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return Err(e.into());
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}
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};
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// Append to accumulator. RESP for our usage is ASCII-safe.
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acc.push_str(str::from_utf8(&buf[..n])?);
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// Try to parse as many complete commands as are available in 'acc'.
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loop {
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let parsed = Cmd::from(&acc);
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let (cmd, protocol, remaining) = match parsed {
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Ok((cmd, protocol, remaining)) => (cmd, protocol, remaining),
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Err(_e) => {
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// Incomplete or invalid frame; assume incomplete and wait for more data.
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// This avoids emitting spurious protocol_error for split frames.
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break;
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}
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};
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// Advance the accumulator to the unparsed remainder
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acc = remaining.to_string();
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if self.option.debug {
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println!("\x1b[34;1mgot command: {:?}, protocol: {:?}\x1b[0m", cmd, protocol);
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} else {
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println!("got command: {:?}, protocol: {:?}", cmd, protocol);
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}
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// Check if this is a QUIT command before processing
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let is_quit = matches!(cmd, Cmd::Quit);
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let res = match cmd.run(self).await {
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Ok(p) => p,
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Err(e) => {
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if self.option.debug {
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eprintln!("[run error] {:?}", e);
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}
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Protocol::err(&format!("ERR {}", e.0))
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}
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};
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if self.option.debug {
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println!("\x1b[34;1mqueued cmd {:?}\x1b[0m", self.queued_cmd);
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println!("\x1b[32;1mgoing to send response {}\x1b[0m", res.encode());
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} else {
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print!("queued cmd {:?}", self.queued_cmd);
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println!("going to send response {}", res.encode());
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}
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_ = stream.write(res.encode().as_bytes()).await?;
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// If this was a QUIT command, close the connection
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if is_quit {
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println!("[handle] QUIT command received, closing connection");
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return Ok(());
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}
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// Continue parsing any further complete commands already in 'acc'
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if acc.is_empty() {
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break;
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}
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}
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}
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}
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}
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