gpt: conditionally spawn new worker

src/worker.rs

@@ -4,11 +4,12 @@ use std::sync::{mpsc, Arc, Mutex};
 struct Worker {
     id: usize,
     receiver: Arc<Mutex<mpsc::Receiver<Task>>>,
+    is_active: Arc<Mutex<bool>>,
 }
 
 impl Worker {
-    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Task>>>) -> Worker {
-        Worker { id, receiver }
+    fn new(id: usize, receiver: Arc<Mutex<mpsc::Receiver<Task>>>, is_active: Arc<Mutex<bool>>) -> Worker {
+        Worker { id, receiver, is_active }
     }
 
     fn start(self) {
@@ -26,6 +27,9 @@ impl Worker {
                     }
                 }
             }
+
+            // Set is_active to false when the worker is done
+            *self.is_active.lock().unwrap() = false;
         });
     }
 }
@@ -35,30 +39,38 @@ type Task = String;
 fn main() {
     let (sender, receiver) = mpsc::channel::<Task>();
     let receiver = Arc::new(Mutex::new(receiver));
+    let is_active = Arc::new(Mutex::new(true));
 
-    // Create a worker thread
-    let worker = Worker::new(1, Arc::clone(&receiver));
+    // Create the first worker thread
+    let worker = Worker::new(1, Arc::clone(&receiver), Arc::clone(&is_active));
 
-    // Start the worker thread
+    // Start the first worker thread
     worker.start();
 
-    // Send tasks to the worker
+    // Send tasks to the first worker
     for i in 0..5 {
         let task = format!("Task {}", i);
         sender.send(task).unwrap();
     }
 
-    // Optional: Signal the worker to stop (in a real-world scenario)
+    // Optional: Signal the first worker to stop (in a real-world scenario)
     // sender.send("STOP".to_string()).unwrap();
 
-    // Sleep to allow worker thread to finish processing
+    // Sleep to allow the first worker thread to finish processing
     thread::sleep(std::time::Duration::from_secs(2));
 
-    // Send another task, which will spawn a new worker
-    let new_worker = Worker::new(2, Arc::clone(&receiver));
+    // Check if the first worker is still active
+    let is_first_worker_active = *is_active.lock().unwrap();
+
+    if !is_first_worker_active {
+        // If the first worker is done, spawn a new worker
+        let new_worker = Worker::new(2, Arc::clone(&receiver), Arc::clone(&is_active));
         new_worker.start();
         sender.send("New Task".to_string()).unwrap();
 
         // Sleep to allow the new worker thread to process the task
         thread::sleep(std::time::Duration::from_secs(2));
+    } else {
+        println!("First worker is still active. Skipping new worker.");
+    }
 }