Fixed leaked sock states, issue tokio-rs#1146. Changes after review, …

…keep things simple in the Drop impl.

Signed-off-by: Daniel Tacalau <dst4096@gmail.com>

src/sys/windows/selector.rs

@@ -394,9 +394,30 @@ unsafe impl Sync for SelectorInner {}
 impl Drop for SelectorInner {
     fn drop(&mut self) {
         loop {
-            let mut events = Events::with_capacity(1024);
-            let _ = self.select(&mut events, Some(std::time::Duration::from_millis(0)));
-            if events.events.len() < 1024 {
+            let events_num: usize;
+            let mut statuses: [CompletionStatus; 1024] = [CompletionStatus::zero(); 1024];
+
+            let result = self
+                .cp
+                .get_many(&mut statuses, Some(std::time::Duration::from_millis(0)));
+            match result {
+                Ok(iocp_events) => {
+                    events_num = iocp_events.iter().len();
+                    for iocp_event in iocp_events.iter() {
+                        if iocp_event.overlapped().is_null() == false {
+                            // drain sock state to release memory of Arc reference
+                            let _sock_state = from_overlapped(iocp_event.overlapped());
+                        }
+                    }
+                }
+
+                Err(_) => {
+                    break;
+                }
+            }
+
+            if events_num < 1024 {
+                // continue looping until all completion statuses have been drained
                 break;
             }
         }