feat: introduce threadpool

src/client.rs

@@ -1,7 +1,7 @@
 use crate::{
     peer::{DefaultPeer, Peer},
     server::{PeerAddress, Server},
-    utils::md5,
+    utils::{md5, thread_pool::ThreadPool},
 };
 use std::{
     collections::HashMap,
@@ -15,18 +15,22 @@ use std::{
     sync::{mpsc, Arc},
     time::{Duration, Instant},
 };
+
+const MAX_THREADS: usize = 100;
 pub enum ClientOperation {
     ConnectToPeer(Peer),
 }
 struct ClientContext {
     peers: HashMap<String, DefaultPeer>,
     sender: Option<Sender<ClientOperation>>,
+    thread_pool: ThreadPool,
 }
 impl ClientContext {
     pub fn new() -> Self {
         Self {
             peers: HashMap::new(),
             sender: None,
+            thread_pool: ThreadPool::new(MAX_THREADS),
         }
     }
 }
@@ -139,7 +143,7 @@ impl Client {
             if !unlocked_context.peers.contains_key(&peer.username) {
                 let peer_clone = peer.clone();
                 let sender_clone = sender.clone();
-                thread::spawn(move || {
+                unlocked_context.thread_pool.execute(move || {
                     let default_peer = DefaultPeer::new(peer_clone, sender_clone);
                     match default_peer.connect() {
                         Ok(p) => {

src/peer/mod.rs

@@ -53,7 +53,7 @@ pub struct Peer {
     pub obfuscated_port: i8,
 }
 impl Peer {
-    #[allow(clippy::too_many_arguments)]
+    #[allow(clippy::too_many_arguments, dead_code)]
     pub fn new(
         username: String,
         connection_type: ConnectionType,
@@ -155,3 +155,4 @@ fn test_new_from_message2() {
     assert_eq!(peer.unknown, 1);
     assert_eq!(peer.obfuscated_port, 0);
 }
+

src/utils/mod.rs

@@ -1,4 +1,5 @@
 pub mod md5;
+pub mod thread_pool;
 pub mod zlib;
 
 pub use md5::*;

src/utils/thread_pool.rs

@@ -0,0 +1,69 @@
+use std::sync::{mpsc, Arc, Mutex};
+use std::thread;
+
+type Job = Box<dyn FnOnce() + Send + 'static>;
+
+pub struct ThreadPool {
+    workers: Vec<Worker>,
+    sender: mpsc::Sender<Job>,
+}
+
+impl ThreadPool {
+    pub fn new(size: usize) -> ThreadPool {
+        assert!(size > 0);
+
+        let (sender, receiver) = mpsc::channel();
+        let receiver = Arc::new(Mutex::new(receiver));
+        let mut workers = Vec::with_capacity(size);
+
+        for id in 0..size {
+            workers.push(Worker::new(id, Arc::clone(&receiver)));
+        }
+
+        ThreadPool { workers, sender }
+    }
+
+    pub fn execute<F>(&self, f: F)
+    where
+        F: FnOnce() + Send + 'static,
+    {
+        let job = Box::new(f);
+        self.sender.send(job).unwrap();
+    }
+}
+
+impl Drop for ThreadPool {
+    fn drop(&mut self) {
+        for worker in &mut self.workers {
+            if let Some(thread) = worker.thread.take() {
+                thread.join().unwrap();
+            }
+        }
+    }
+}
+
+struct Worker {
+    _id: usize,
+    thread: Option<thread::JoinHandle<()>>,
+}
+
+impl Worker {
+    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Job>>>) -> Worker {
+        let thread = thread::spawn(move || loop {
+            let job = receiver.lock().unwrap().recv();
+            match job {
+                Ok(job) => {
+                    job();
+                }
+                Err(_) => {
+                    break;
+                }
+            }
+        });
+
+        Worker {
+            _id: id,
+            thread: Some(thread),
+        }
+    }
+}