Keep Open and Save asynchronous to prevent macOS resize crashes (#1127)

Open and Save use parented AsyncFileDialog sheets; their answers run on the UI thread in a later frame, so resizing the window while a picker is open no longer re-enters winit and aborts. Editors, tab changes, Close/Quit and model-changing control requests wait for the answer; the local library Open and Export in the Appearance dialog use the same flow. Fixes #1088.

apps/solidcraft-web/src/main.rs

@@ -73,6 +73,12 @@ mod web {
             if self.files.ctx.borrow().is_none() {
                 *self.files.ctx.borrow_mut() = Some(ctx.clone());
             }
+            // A ready picker answer is consumed in app.logic later in this frame. Keep
+            // incoming files queued until then so they cannot replace its target design.
+            if self.app.file_picker_busy() {
+                ctx.request_repaint();
+                return;
+            }
             files::flush(&self.files);
             for (text, error) in self.files.messages.borrow_mut().drain(..) {
                 self.app.set_status(text, error);
@@ -434,12 +440,12 @@ mod web {
                             // Open shows the browser's files (and the computer's, from there).
                             pick_open: Some(Box::new(move || {
                                 panel.panel.set(true);
-                                None
+                                Box::pin(std::future::ready(None))
                             })),
                             // Designs are kept in the browser; everything else is downloaded.
                             pick_save: Some(Box::new(|name: &str, exts: &[&str]| {
                                 let design = exts.contains(&solidcraft_engine::io::DESIGN_EXT);
-                                Some(format!("{}{name}", if design { files::OPFS } else { files::DOWNLOADS }))
+                                Box::pin(std::future::ready(Some(format!("{}{name}", if design { files::OPFS } else { files::DOWNLOADS }))))
                             })),
                             ..Default::default()
                         };

apps/solidcraft/src/main.rs

@@ -50,12 +50,14 @@ impl eframe::App for App {
             solidcraft_ui_egui::documents::request_quit(&mut self.solve);
         }
         #[cfg(target_os = "macos")]
-        for f in open_documents::take() {
+        for f in if self.solve.file_picker_busy() { Vec::new() } else { open_documents::take() } {
             self.solve.open_path_async(&f);
         }
         self.solve.logic(ctx);
         #[cfg(any(target_os = "windows", target_os = "linux"))]
-        self.space_mouse.tick(&mut self.solve, ctx);
+        if !self.solve.file_picker_busy() {
+            self.space_mouse.tick(&mut self.solve, ctx);
+        }
         if self.solve.quit_requested {
             ctx.send_viewport_cmd(egui::ViewportCommand::Close);
         }
@@ -81,10 +83,13 @@ impl eframe::App for App {
     }
 }
 
-fn services() -> Services {
+fn services(cc: &eframe::CreationContext<'_>) -> Services {
+    let parent = rfd::AsyncFileDialog::new().set_parent(cc);
+    let open_parent = parent.clone();
     Services {
-        pick_open: Some(Box::new(|| {
-            rfd::FileDialog::new()
+        pick_open: Some(Box::new(move || {
+            let future = open_parent
+                .clone()
                 .add_filter(
                     "Designs, STEP, IGES and meshes",
                     &[
@@ -111,11 +116,11 @@ fn services() -> Services {
                 .add_filter("Mesh (3MF, STL)", &["3mf", "3MF", "stl", "STL"])
                 .add_filter("Sketch drawings (DXF, SVG)", &["dxf", "DXF", "svg", "SVG"])
                 .add_filter("All files", &["*"])
-                .pick_file()
-                .map(|p| p.to_string_lossy().to_string())
+                .pick_file();
+            Box::pin(async move { future.await.map(|p| p.path().to_string_lossy().into_owned()) })
         })),
-        pick_save: Some(Box::new(|name: &str, exts: &[&str]| {
-            let dialog = rfd::FileDialog::new().set_file_name(name);
+        pick_save: Some(Box::new(move |name: &str, exts: &[&str]| {
+            let dialog = parent.clone().set_file_name(name);
             let dialog = if exts == [io::DESIGN_EXT, "json"] {
                 if name.ends_with(".json") {
                     dialog.add_filter("Plain JSON design", &["json"]).add_filter("SolidCraft container", &[io::DESIGN_EXT])
@@ -125,7 +130,8 @@ fn services() -> Services {
             } else {
                 dialog.add_filter("File", exts)
             };
-            dialog.save_file().map(|p| p.to_string_lossy().to_string())
+            let future = dialog.save_file();
+            Box::pin(async move { future.await.map(|p| p.path().to_string_lossy().into_owned()) })
         })),
         graphics_path: graphics_path().map(|p| p.to_string_lossy().to_string()),
         http_get: Some(std::sync::Arc::new(http_get)),
@@ -422,7 +428,7 @@ fn main() -> eframe::Result {
         Box::new(move |cc| {
             created_in_app.store(true, std::sync::atomic::Ordering::SeqCst);
             solidcraft_ui_egui::fonts::setup_fonts(&cc.egui_ctx);
-            let mut app = SolveApp::new(Session::default(), services());
+            let mut app = SolveApp::new(Session::default(), services(cc));
             app.custom_titlebar = CUSTOM_TITLEBAR;
             app.integrated_titlebar = cfg!(target_os = "macos");
             app.cpu_meshing = safe_mode;