fixes, docs

eframe/src/lib.rs

@@ -90,6 +90,20 @@ use web::AppRunner;
 #[cfg(target_arch = "wasm32")]
 pub use web_sys;
 
+#[cfg(target_arch = "wasm32")]
+use arc_swap::ArcSwapOption;
+
+#[cfg(target_arch = "wasm32")]
+#[allow(unsafe_code)]
+unsafe impl Send for AppRunner {}
+
+#[cfg(target_arch = "wasm32")]
+#[allow(unsafe_code)]
+unsafe impl Sync for AppRunner {}
+
+#[cfg(target_arch = "wasm32")]
+static GLOBAL_HANDLE: ArcSwapOption<Mutex<AppRunner>> = ArcSwapOption::const_empty();
+
 /// Install event listeners to register different input events
 /// and start running the given app.
 ///
@@ -98,8 +112,9 @@ pub use web_sys;
 /// use wasm_bindgen::prelude::*;
 ///
 /// /// This is the entry-point for all the web-assembly.
-/// /// This is called once from the HTML.
+/// /// This is called from the HTML.
 /// /// It loads the app, installs some callbacks, then returns.
+/// /// It creates singleton app-handle that could be stopped calling `stop_web`
 /// /// You can add more callbacks like this if you want to call in to your code.
 /// #[cfg(target_arch = "wasm32")]
 /// #[wasm_bindgen]
@@ -128,10 +143,13 @@ pub fn start_web(canvas_id: &str, web_options: WebOptions, app_creator: AppCreat
     Ok(())
 }
 
+/// Stop all event listeners, created by start_web.
+/// /// `start_web` could be called again after calling this.
+/// /// It aims to destroy all Arc's to `AppRunner` to not cause memory leak in start/stop cycless
 #[cfg(target_arch = "wasm32")]
 pub fn stop_web() -> Result<(), wasm_bindgen::JsValue> {
     if let Some(app_runner) = GLOBAL_HANDLE.load_full() {
-        uu.lock().destroy();
+        app_runner.lock().destroy()?;
 
         GLOBAL_HANDLE.store(None);
 

eframe/src/web/backend.rs

@@ -2,9 +2,7 @@ use super::{glow_wrapping::WrappedGlowPainter, *};
 
 use crate::epi;
 
-use egui::mutex::{Mutex, MutexGuard};
 use egui::TexturesDelta;
-
 pub use egui::{pos2, Color32};
 
 // ----------------------------------------------------------------------------
@@ -36,38 +34,24 @@ impl WebInput {
 
 use std::sync::atomic::Ordering::SeqCst;
 
-/// Stores when to do the next repaint.
-pub struct NeedRepaint(Mutex<f64>);
+pub struct NeedRepaint(std::sync::atomic::AtomicBool);
 
 impl Default for NeedRepaint {
     fn default() -> Self {
-        Self(Mutex::new(f64::NEG_INFINITY)) // start with a repaint
+        Self(true.into())
     }
 }
 
 impl NeedRepaint {
-    /// Returns the time (in [`now_sec`] scale) when
-    /// we should next repaint.
-    pub fn when_to_repaint(&self) -> f64 {
-        *self.0.lock()
-    }
-
-    /// Unschedule repainting.
-    pub fn clear(&self) {
-        *self.0.lock() = f64::INFINITY;
+    pub fn fetch_and_clear(&self) -> bool {
+        self.0.swap(false, SeqCst)
     }
 
-    pub fn repaint_after(&self, num_seconds: f64) {
-        let mut repaint_time = self.0.lock();
-        *repaint_time = repaint_time.min(now_sec() + num_seconds);
-    }
-
-    pub fn repaint_asap(&self) {
-        *self.0.lock() = f64::NEG_INFINITY;
+    pub fn set_true(&self) {
+        self.0.store(true, SeqCst);
     }
 }
 
-
 pub struct IsDestroyed(std::sync::atomic::AtomicBool);
 
 impl Default for IsDestroyed {
@@ -238,7 +222,7 @@ impl AppRunner {
         {
             let needs_repaint = needs_repaint.clone();
             egui_ctx.set_request_repaint_callback(move || {
-                needs_repaint.repaint_asap();
+                needs_repaint.0.store(true, SeqCst);
             });
         }
 
@@ -297,15 +281,16 @@ impl AppRunner {
         Ok(())
     }
 
-    pub fn destroy(&mut self) {
+    pub fn destroy(&mut self) -> Result<(), JsValue> {
         tracing::debug!("destroying...");
 
-        self.events_to_unsubscribe
-            .drain(..)
-            .for_each(|x| x.unsubscribe());
+        for x in self.events_to_unsubscribe.drain(..) {
+            x.unsubscribe()?;
+        }
 
         self.painter.destroy();
         self.is_destroyed.set_true();
+        Ok(())
     }
 
     /// Returns how long to wait until the next repaint.
@@ -408,11 +393,48 @@ impl AppRunner {
 
 pub type AppRunnerRef = Arc<Mutex<AppRunner>>;
 
+pub struct TargetEvent {
+    target: EventTarget,
+    event_name: String,
+    closure: Closure<dyn FnMut(web_sys::Event)>,
+}
+
+pub struct RepetitativeHandle {
+    pub handle: i32,
+    pub closure: Closure<dyn FnMut()>,
+}
+
+pub enum EventToUnsubscribe {
+    TargetEvent(TargetEvent),
+    RepititativeHandle(RepetitativeHandle),
+}
+
+impl EventToUnsubscribe {
+    pub fn unsubscribe(self) -> Result<(), JsValue> {
+        use wasm_bindgen::JsCast;
+
+        match self {
+            EventToUnsubscribe::TargetEvent(handle) => {
+                handle.target.remove_event_listener_with_callback(
+                    handle.event_name.as_str(),
+                    handle.closure.as_ref().unchecked_ref(),
+                )?;
+                Ok(())
+            }
+            EventToUnsubscribe::RepititativeHandle(handle) => {
+                let window = web_sys::window().unwrap();
+                window.clear_interval_with_handle(handle.handle);
+                Ok(())
+            }
+        }
+    }
+}
 pub struct AppRunnerContainer {
     pub runner: AppRunnerRef,
     /// Set to `true` if there is a panic.
     /// Used to ignore callbacks after a panic.
     pub panicked: Arc<AtomicBool>,
+    pub events: Vec<EventToUnsubscribe>,
 }
 
 impl AppRunnerContainer {
@@ -457,9 +479,6 @@ impl AppRunnerContainer {
 
         self.events.push(EventToUnsubscribe::TargetEvent(handle));
 
-        // Bypass closure drop so that event handler can call the closure
-        // closure.forget();
-
         Ok(())
     }
 }