fix unexpected return via whitelist block by raii

Signed-off-by: 21pages <pages21@163.com>

src/server/connection.rs

@@ -241,12 +241,12 @@ impl Connection {
         id: i32,
         server: super::ServerPtrWeak,
     ) {
+        let _raii_id = raii::ConnectionID::new(id);
         let hash = Hash {
             salt: Config::get_salt(),
             challenge: Config::get_auto_password(6),
             ..Default::default()
         };
-        ALIVE_CONNS.lock().unwrap().push(id);
         let (tx_from_cm_holder, mut rx_from_cm) = mpsc::unbounded_channel::<ipc::Data>();
         // holding tx_from_cm_holder to avoid cpu burning of rx_from_cm.recv when all sender closed
         let tx_from_cm = tx_from_cm_holder.clone();
@@ -627,22 +627,12 @@ impl Connection {
         conn.post_conn_audit(json!({
             "action": "close",
         }));
-        let mut active_conns_lock = ALIVE_CONNS.lock().unwrap();
-        active_conns_lock.retain(|&c| c != id);
         if let Some(s) = conn.server.upgrade() {
             let mut s = s.write().unwrap();
             s.remove_connection(&conn.inner);
             #[cfg(not(any(target_os = "android", target_os = "ios")))]
             try_stop_record_cursor_pos();
         }
-        #[cfg(not(any(target_os = "android", target_os = "ios")))]
-        if active_conns_lock.is_empty() {
-            video_service::reset_resolutions();
-        }
-        #[cfg(all(windows, feature = "virtual_display_driver"))]
-        if active_conns_lock.is_empty() {
-            video_service::try_plug_out_virtual_display();
-        }
         log::info!("#{} connection loop exited", id);
     }
 
@@ -2538,3 +2528,30 @@ impl Drop for Connection {
         self.release_pressed_modifiers();
     }
 }
+
+mod raii {
+    use super::*;
+    pub struct ConnectionID(i32);
+
+    impl ConnectionID {
+        pub fn new(id: i32) -> Self {
+            ALIVE_CONNS.lock().unwrap().push(id);
+            Self(id)
+        }
+    }
+
+    impl Drop for ConnectionID {
+        fn drop(&mut self) {
+            let mut active_conns_lock = ALIVE_CONNS.lock().unwrap();
+            active_conns_lock.retain(|&c| c != self.0);
+            #[cfg(not(any(target_os = "android", target_os = "ios")))]
+            if active_conns_lock.is_empty() {
+                video_service::reset_resolutions();
+            }
+            #[cfg(all(windows, feature = "virtual_display_driver"))]
+            if active_conns_lock.is_empty() {
+                video_service::try_plug_out_virtual_display();
+            }
+        }
+    }
+}