Use Vec::drain() to move thread out of the vector #3248

listings/ch20-web-server/listing-20-23/src/lib.rs

@@ -61,20 +61,18 @@ impl Drop for ThreadPool {
     fn drop(&mut self) {
         drop(self.sender.take());
 
-        for worker in &mut self.workers {
+        for worker in self.workers.drain(..) {
             println!("Shutting down worker {}", worker.id);
 
-            if let Some(thread) = worker.thread.take() {
-                thread.join().unwrap();
-            }
+            worker.thread.join().unwrap();
         }
     }
 }
 // ANCHOR_END: here
 
 struct Worker {
     id: usize,
-    thread: Option<thread::JoinHandle<()>>,
+    thread: thread::JoinHandle<()>,
 }
 
 impl Worker {
@@ -89,7 +87,7 @@ impl Worker {
 
         Worker {
             id,
-            thread: Some(thread),
+            thread: thread,
         }
     }
 }

listings/ch20-web-server/listing-20-24/src/lib.rs

@@ -51,19 +51,17 @@ impl Drop for ThreadPool {
     fn drop(&mut self) {
         drop(self.sender.take());
 
-        for worker in &mut self.workers {
+        for worker in self.workers.drain(..) {
             println!("Shutting down worker {}", worker.id);
 
-            if let Some(thread) = worker.thread.take() {
-                thread.join().unwrap();
-            }
+            worker.thread.join().unwrap();
         }
     }
 }
 
 struct Worker {
     id: usize,
-    thread: Option<thread::JoinHandle<()>>,
+    thread: thread::JoinHandle<()>,
 }
 
 // ANCHOR: here
@@ -85,7 +83,7 @@ impl Worker {
 
         Worker {
             id,
-            thread: Some(thread),
+            thread: thread,
         }
     }
 }

listings/ch20-web-server/listing-20-25/src/lib.rs

@@ -51,19 +51,17 @@ impl Drop for ThreadPool {
     fn drop(&mut self) {
         drop(self.sender.take());
 
-        for worker in &mut self.workers {
+        for worker in self.workers.drain(..) {
             println!("Shutting down worker {}", worker.id);
 
-            if let Some(thread) = worker.thread.take() {
-                thread.join().unwrap();
-            }
+            worker.thread.join().unwrap();
         }
     }
 }
 
 struct Worker {
     id: usize,
-    thread: Option<thread::JoinHandle<()>>,
+    thread: thread::JoinHandle<()>,
 }
 
 impl Worker {
@@ -86,7 +84,7 @@ impl Worker {
 
         Worker {
             id,
-            thread: Some(thread),
+            thread: thread,
         }
     }
 }