fix clipboard crash and https://github.com/rustdesk/rustdesk/issues/302

src/common.rs

@@ -95,7 +95,10 @@ pub fn update_clipboard(clipboard: Clipboard, old: Option<&Arc<Mutex<String>>>)
                 let side = if old.is_none() { "host" } else { "client" };
                 let old = if let Some(old) = old { old } else { &CONTENT };
                 *old.lock().unwrap() = content.clone();
-                allow_err!(ctx.set_text(content));
+                if !content.is_empty() {
+                    // empty content make ctx.set_text crash
+                    allow_err!(ctx.set_text(content));
+                }
                 log::debug!("{} updated on {}", CLIPBOARD_NAME, side);
             }
             Err(err) => {
@@ -240,7 +243,8 @@ async fn test_nat_type_() -> ResultType<bool> {
     let rendezvous_server = get_rendezvous_server(100).await;
     let server1 = rendezvous_server;
     let mut server2 = server1;
-    if server1.port() == 0 { // offline
+    if server1.port() == 0 {
+        // offline
         // avoid overflow crash
         bail!("Offline");
     }

src/server/clipboard_service.rs

@@ -97,8 +97,12 @@ mod listen {
 
     fn trigger(ctx: &mut ClipboardContext) {
         let _ = match ctx.get_text() {
-            Ok(text) => ctx.set_text(text),
-            Err(_) => ctx.set_text(Default::default()),
+            Ok(text) => {
+                if !text.is_empty() {
+                    ctx.set_text(text).ok();
+                }
+            }
+            Err(_) => {}
         };
     }
 }

src/server/video_service.rs

@@ -220,7 +220,7 @@ fn run(sp: GenericService) -> ResultType<()> {
     let start = time::Instant::now();
     let mut last_check_displays = time::Instant::now();
     #[cfg(windows)]
-    let mut try_gdi = true;
+    let mut try_gdi = 1;
     #[cfg(windows)]
     log::info!("gdi: {}", c.is_gdi());
     while sp.ok() {
@@ -261,7 +261,7 @@ fn run(sp: GenericService) -> ResultType<()> {
                 frame_controller.set_send(now, send_conn_ids);
                 #[cfg(windows)]
                 {
-                    try_gdi = false;
+                    try_gdi = 0;
                 }
             }
             Err(ref e) if e.kind() == WouldBlock => {
@@ -271,10 +271,13 @@ fn run(sp: GenericService) -> ResultType<()> {
                     wait = 0
                 }
                 #[cfg(windows)]
-                if try_gdi && !c.is_gdi() {
-                    c.set_gdi();
-                    try_gdi = false;
-                    log::info!("No image, fall back to gdi");
+                if try_gdi > 0 && !c.is_gdi() {
+                    if try_gdi > 3 {
+                        c.set_gdi();
+                        try_gdi = 0;
+                        log::info!("No image, fall back to gdi");
+                    }
+                    try_gdi += 1;
                 }
                 continue;
             }