fix(clipboard-manager): Drop on exit

ref https://docs.rs/arboard/latest/arboard/struct.Clipboard.html
ref https://github.com/tauri-apps/plugins-workspace/issues/2267

.changes/clipboard-drop.md

@@ -0,0 +1,6 @@
+---
+clipboard-manager: patch
+clipboard-manager-js: patch
+---
+
+Explicitly drop `arboard::Clipboard` on exit. Add recommendation to not use read methods on the mainthread.

plugins/clipboard-manager/src/desktop.rs

@@ -14,7 +14,7 @@ pub fn init<R: Runtime, C: DeserializeOwned>(
 ) -> crate::Result<Clipboard<R>> {
     Ok(Clipboard {
         app: app.clone(),
-        clipboard: arboard::Clipboard::new().map(Mutex::new),
+        clipboard: arboard::Clipboard::new().map(|c| Mutex::new(Some(c))),
     })
 }
 
@@ -22,13 +22,21 @@ pub fn init<R: Runtime, C: DeserializeOwned>(
 pub struct Clipboard<R: Runtime> {
     #[allow(dead_code)]
     app: AppHandle<R>,
-    clipboard: Result<Mutex<arboard::Clipboard>, arboard::Error>,
+    // According to arboard docs the clipboard must be dropped before exit.
+    // Since tauri doesn't call drop on exit we'll use an Option to take() on RunEvent::Exit.
+    clipboard: Result<Mutex<Option<arboard::Clipboard>>, arboard::Error>,
 }
 
 impl<R: Runtime> Clipboard<R> {
     pub fn write_text<'a, T: Into<Cow<'a, str>>>(&self, text: T) -> crate::Result<()> {
         match &self.clipboard {
-            Ok(clipboard) => clipboard.lock().unwrap().set_text(text).map_err(Into::into),
+            Ok(clipboard) => clipboard
+                .lock()
+                .unwrap()
+                .as_mut()
+                .unwrap()
+                .set_text(text)
+                .map_err(Into::into),
             Err(e) => Err(crate::Error::Clipboard(e.to_string())),
         }
     }
@@ -38,6 +46,8 @@ impl<R: Runtime> Clipboard<R> {
             Ok(clipboard) => clipboard
                 .lock()
                 .unwrap()
+                .as_mut()
+                .unwrap()
                 .set_image(ImageData {
                     bytes: Cow::Borrowed(image.rgba()),
                     width: image.width() as usize,
@@ -48,10 +58,11 @@ impl<R: Runtime> Clipboard<R> {
         }
     }
 
+    /// Warning: This method should not be used on the main thread! Otherwise the underlying libraries may deadlock on Linux, freezing the whole app.
     pub fn read_text(&self) -> crate::Result<String> {
         match &self.clipboard {
             Ok(clipboard) => {
-                let text = clipboard.lock().unwrap().get_text()?;
+                let text = clipboard.lock().unwrap().as_mut().unwrap().get_text()?;
                 Ok(text)
             }
             Err(e) => Err(crate::Error::Clipboard(e.to_string())),
@@ -67,6 +78,8 @@ impl<R: Runtime> Clipboard<R> {
             Ok(clipboard) => clipboard
                 .lock()
                 .unwrap()
+                .as_mut()
+                .unwrap()
                 .set_html(html, alt_text)
                 .map_err(Into::into),
             Err(e) => Err(crate::Error::Clipboard(e.to_string())),
@@ -75,15 +88,22 @@ impl<R: Runtime> Clipboard<R> {
 
     pub fn clear(&self) -> crate::Result<()> {
         match &self.clipboard {
-            Ok(clipboard) => clipboard.lock().unwrap().clear().map_err(Into::into),
+            Ok(clipboard) => clipboard
+                .lock()
+                .unwrap()
+                .as_mut()
+                .unwrap()
+                .clear()
+                .map_err(Into::into),
             Err(e) => Err(crate::Error::Clipboard(e.to_string())),
         }
     }
 
+    /// Warning: This method should not be used on the main thread! Otherwise the underlying libraries may deadlock on Linux, freezing the whole app.
     pub fn read_image(&self) -> crate::Result<Image<'_>> {
         match &self.clipboard {
             Ok(clipboard) => {
-                let image = clipboard.lock().unwrap().get_image()?;
+                let image = clipboard.lock().unwrap().as_mut().unwrap().get_image()?;
                 let image = Image::new_owned(
                     image.bytes.to_vec(),
                     image.width as u32,
@@ -94,4 +114,10 @@ impl<R: Runtime> Clipboard<R> {
             Err(e) => Err(crate::Error::Clipboard(e.to_string())),
         }
     }
+
+    pub(crate) fn cleanup(&self) {
+        if let Ok(clipboard) = &self.clipboard {
+            clipboard.lock().unwrap().take();
+        }
+    }
 }

plugins/clipboard-manager/src/lib.rs

@@ -11,7 +11,7 @@
 
 use tauri::{
     plugin::{Builder, TauriPlugin},
-    Manager, Runtime,
+    Manager, RunEvent, Runtime,
 };
 
 #[cfg(desktop)]
@@ -59,5 +59,11 @@ pub fn init<R: Runtime>() -> TauriPlugin<R> {
             app.manage(clipboard);
             Ok(())
         })
+        .on_event(|_app, _event| {
+            #[cfg(desktop)]
+            if let RunEvent::Exit = _event {
+                _app.clipboard().cleanup();
+            }
+        })
         .build()
 }