fix(core): emit tauri://close-requested to JS, closes #2996 (#3041)

.changes/fix-close-requested-js-event.md

@@ -0,0 +1,5 @@
+---
+"tauri": patch
+---
+
+Prevent window closing if `tauri://close-requested` is listened on the JS layer. Users must call `appWindow.close()` manually when listening to that event.

.changes/refactor-window-event-close-requested.md

@@ -0,0 +1,5 @@
+---
+"tauri": patch
+---
+
+**Breaking change:** The `WindowEvent::CloseRequested` variant now includes `label` and `signal_tx` fields to allow preventing closing the window.

core/tauri-runtime-wry/src/lib.rs

@@ -88,7 +88,7 @@ pub use wry::application::platform::macos::{
 use std::{
   collections::{
     hash_map::Entry::{Occupied, Vacant},
-    HashMap,
+    HashMap, HashSet,
   },
   fmt,
   fs::read,
@@ -555,7 +555,6 @@ impl<'a> From<&WryWindowEvent<'a>> for WindowEventWrapper {
       WryWindowEvent::Moved(position) => {
         WindowEvent::Moved(PhysicalPositionWrapper(*position).into())
       }
-      WryWindowEvent::CloseRequested => WindowEvent::CloseRequested,
       WryWindowEvent::Destroyed => WindowEvent::Destroyed,
       WryWindowEvent::ScaleFactorChanged {
         scale_factor,
@@ -1213,6 +1212,7 @@ impl Dispatch for WryDispatcher {
     let (tx, rx) = channel();
     let label = pending.label.clone();
     let menu_ids = pending.menu_ids.clone();
+    let js_event_listeners = pending.js_event_listeners.clone();
     let context = self.context.clone();
 
     send_user_message(
@@ -1234,6 +1234,7 @@ impl Dispatch for WryDispatcher {
       label,
       dispatcher,
       menu_ids,
+      js_event_listeners,
     })
   }
 
@@ -1521,6 +1522,7 @@ impl RuntimeHandle for WryHandle {
     let (tx, rx) = channel();
     let label = pending.label.clone();
     let menu_ids = pending.menu_ids.clone();
+    let js_event_listeners = pending.js_event_listeners.clone();
     let context = self.context.clone();
     send_user_message(
       &self.context,
@@ -1541,6 +1543,7 @@ impl RuntimeHandle for WryHandle {
       label,
       dispatcher,
       menu_ids,
+      js_event_listeners,
     })
   }
 
@@ -1649,6 +1652,7 @@ impl Runtime for Wry {
   fn create_window(&self, pending: PendingWindow<Self>) -> Result<DetachedWindow<Self>> {
     let label = pending.label.clone();
     let menu_ids = pending.menu_ids.clone();
+    let js_event_listeners = pending.js_event_listeners.clone();
     let proxy = self.event_loop.create_proxy();
     let webview = create_webview(
       &self.event_loop,
@@ -1738,6 +1742,7 @@ impl Runtime for Wry {
       label,
       dispatcher,
       menu_ids,
+      js_event_listeners,
     })
   }
 
@@ -2356,6 +2361,20 @@ fn handle_event_loop(
           if let Some(w) = windows_guard.get(&window_id) {
             let label = w.label.clone();
             drop(windows_guard);
+            for handler in window_event_listeners
+              .lock()
+              .unwrap()
+              .get(&window_id)
+              .unwrap()
+              .lock()
+              .unwrap()
+              .values()
+            {
+              handler(&WindowEvent::CloseRequested {
+                label: label.clone(),
+                signal_tx: tx.clone(),
+              });
+            }
             callback(RunEvent::CloseRequested {
               label,
               signal_tx: tx,
@@ -2534,6 +2553,7 @@ fn create_webview(
     label,
     url,
     menu_ids,
+    js_event_listeners,
     ..
   } = pending;
 
@@ -2573,6 +2593,7 @@ fn create_webview(
       context.clone(),
       label.clone(),
       menu_ids.clone(),
+      js_event_listeners.clone(),
       handler,
     ));
   }
@@ -2581,6 +2602,7 @@ fn create_webview(
       context,
       label.clone(),
       menu_ids,
+      js_event_listeners,
       handler,
     ));
   }
@@ -2637,6 +2659,7 @@ fn create_rpc_handler(
   context: Context,
   label: String,
   menu_ids: Arc<Mutex<HashMap<MenuHash, MenuId>>>,
+  js_event_listeners: Arc<Mutex<HashMap<String, HashSet<u64>>>>,
   handler: WebviewRpcHandler<Wry>,
 ) -> Box<dyn Fn(&Window, WryRpcRequest) -> Option<RpcResponse> + 'static> {
   Box::new(move |window, request| {
@@ -2648,6 +2671,7 @@ fn create_rpc_handler(
         },
         label: label.clone(),
         menu_ids: menu_ids.clone(),
+        js_event_listeners: js_event_listeners.clone(),
       },
       RpcRequestWrapper(request).into(),
     );
@@ -2660,6 +2684,7 @@ fn create_file_drop_handler(
   context: Context,
   label: String,
   menu_ids: Arc<Mutex<HashMap<MenuHash, MenuId>>>,
+  js_event_listeners: Arc<Mutex<HashMap<String, HashSet<u64>>>>,
   handler: FileDropHandler<Wry>,
 ) -> Box<dyn Fn(&Window, WryFileDropEvent) -> bool + 'static> {
   Box::new(move |window, event| {
@@ -2672,6 +2697,7 @@ fn create_file_drop_handler(
         },
         label: label.clone(),
         menu_ids: menu_ids.clone(),
+        js_event_listeners: js_event_listeners.clone(),
       },
     )
   })

core/tauri-runtime/src/window.rs

@@ -14,9 +14,9 @@ use serde::Serialize;
 use tauri_utils::config::WindowConfig;
 
 use std::{
-  collections::HashMap,
+  collections::{HashMap, HashSet},
   hash::{Hash, Hasher},
-  sync::{Arc, Mutex},
+  sync::{mpsc::Sender, Arc, Mutex},
 };
 
 type UriSchemeProtocol =
@@ -34,7 +34,12 @@ pub enum WindowEvent {
   /// The position of the window has changed. Contains the window's new position.
   Moved(dpi::PhysicalPosition<i32>),
   /// The window has been requested to close.
-  CloseRequested,
+  CloseRequested {
+    /// The window label.
+    label: String,
+    /// A signal sender. If a `true` value is emitted, the window won't be closed.
+    signal_tx: Sender<bool>,
+  },
   /// The window has been destroyed.
   Destroyed,
   /// The window gained or lost focus.
@@ -99,6 +104,9 @@ pub struct PendingWindow<R: Runtime> {
 
   /// Maps runtime id to a string menu id.
   pub menu_ids: Arc<Mutex<HashMap<MenuHash, MenuId>>>,
+
+  /// A HashMap mapping JS event names with listener ids associated.
+  pub js_event_listeners: Arc<Mutex<HashMap<String, HashSet<u64>>>>,
 }
 
 impl<R: Runtime> PendingWindow<R> {
@@ -121,6 +129,7 @@ impl<R: Runtime> PendingWindow<R> {
       file_drop_handler: None,
       url: "tauri://localhost".to_string(),
       menu_ids: Arc::new(Mutex::new(menu_ids)),
+      js_event_listeners: Default::default(),
     }
   }
 
@@ -144,6 +153,7 @@ impl<R: Runtime> PendingWindow<R> {
       file_drop_handler: None,
       url: "tauri://localhost".to_string(),
       menu_ids: Arc::new(Mutex::new(menu_ids)),
+      js_event_listeners: Default::default(),
     }
   }
 
@@ -181,6 +191,9 @@ pub struct DetachedWindow<R: Runtime> {
 
   /// Maps runtime id to a string menu id.
   pub menu_ids: Arc<Mutex<HashMap<MenuHash, MenuId>>>,
+
+  /// A HashMap mapping JS event names with listener ids associated.
+  pub js_event_listeners: Arc<Mutex<HashMap<String, HashSet<u64>>>>,
 }
 
 impl<R: Runtime> Clone for DetachedWindow<R> {
@@ -189,6 +202,7 @@ impl<R: Runtime> Clone for DetachedWindow<R> {
       label: self.label.clone(),
       dispatcher: self.dispatcher.clone(),
       menu_ids: self.menu_ids.clone(),
+      js_event_listeners: self.js_event_listeners.clone(),
     }
   }
 }

core/tauri/src/endpoints/event.rs

@@ -29,11 +29,13 @@ impl Cmd {
     match self {
       Self::Listen { event, handler } => {
         let event_id = rand::random();
-        window.eval(&listen_js(&window, event, event_id, handler))?;
+        window.eval(&listen_js(&window, event.clone(), event_id, handler))?;
+        window.register_js_listener(event, event_id);
         Ok(event_id.into())
       }
       Self::Unlisten { event_id } => {
         window.eval(&unlisten_js(&window, event_id))?;
+        window.unregister_js_listener(event_id);
         Ok(().into())
       }
       Self::Emit {

core/tauri/src/manager.rs

@@ -815,7 +815,13 @@ fn on_window_event<R: Runtime>(
   match event {
     WindowEvent::Resized(size) => window.emit_and_trigger(WINDOW_RESIZED_EVENT, size)?,
     WindowEvent::Moved(position) => window.emit_and_trigger(WINDOW_MOVED_EVENT, position)?,
-    WindowEvent::CloseRequested => {
+    WindowEvent::CloseRequested {
+      label: _,
+      signal_tx,
+    } => {
+      if window.has_js_listener(WINDOW_CLOSE_REQUESTED_EVENT) {
+        signal_tx.send(true).unwrap();
+      }
       window.emit_and_trigger(WINDOW_CLOSE_REQUESTED_EVENT, ())?;
     }
     WindowEvent::Destroyed => {

core/tauri/src/window.rs

@@ -352,6 +352,44 @@ impl<R: Runtime> Window<R> {
     })
   }
 
+  pub(crate) fn register_js_listener(&self, event: String, id: u64) {
+    self
+      .window
+      .js_event_listeners
+      .lock()
+      .unwrap()
+      .entry(event)
+      .or_insert_with(Default::default)
+      .insert(id);
+  }
+
+  pub(crate) fn unregister_js_listener(&self, id: u64) {
+    let mut empty = None;
+    let mut js_listeners = self.window.js_event_listeners.lock().unwrap();
+    for (event, ids) in js_listeners.iter_mut() {
+      if ids.contains(&id) {
+        ids.remove(&id);
+        if ids.is_empty() {
+          empty.replace(event.clone());
+        }
+        break;
+      }
+    }
+
+    if let Some(event) = empty {
+      js_listeners.remove(&event);
+    }
+  }
+
+  pub(crate) fn has_js_listener(&self, event: &str) -> bool {
+    self
+      .window
+      .js_event_listeners
+      .lock()
+      .unwrap()
+      .contains_key(event)
+  }
+
   // Getters
 
   /// Gets a handle to the window menu.