On Wayland, fix deadlock when calling set_inner_size from event loop

Fixes #1571.

CHANGELOG.md

@@ -1,6 +1,8 @@
 # Unreleased
 - On Web, prevent the webpage from scrolling when the user is focused on a winit canvas
 
+- On Wayland, fix deadlock when calling to `set_inner_size` from a callback.
+
 # 0.22.2 (2020-05-16)
 
 - Added Clone implementation for 'static events.

src/platform_impl/linux/wayland/event_loop.rs

@@ -667,6 +667,8 @@ impl<T> EventLoop<T> {
         window_target.store.lock().unwrap().for_each_redraw_trigger(
             |refresh, frame_refresh, wid, frame| {
                 if let Some(frame) = frame {
+                    let mut frame = frame.lock().unwrap();
+
                     if frame_refresh {
                         frame.refresh();
                         if !refresh {
@@ -751,6 +753,7 @@ impl<T> EventLoop<T> {
 
             if window.new_size.is_some() || window.new_scale_factor.is_some() {
                 if let Some(frame) = window.frame {
+                    let mut frame = frame.lock().unwrap();
                     // Update decorations state
                     match window.decorations_action {
                         Some(DecorationsAction::Hide) => frame.set_decorate(false),

src/platform_impl/linux/wayland/window.rs

@@ -461,7 +461,7 @@ pub struct WindowStoreForEach<'a> {
     pub grab_cursor: Option<bool>,
     pub surface: &'a wl_surface::WlSurface,
     pub wid: WindowId,
-    pub frame: Option<&'a mut SWindow<ConceptFrame>>,
+    pub frame: Option<Arc<Mutex<SWindow<ConceptFrame>>>>,
     pub decorations_action: Option<DecorationsAction>,
 }
 
@@ -522,8 +522,7 @@ impl WindowStore {
             if let Some(scale_factor) = window.new_scale_factor {
                 window.current_scale_factor = scale_factor;
             }
-            let opt_arc = window.frame.upgrade();
+            let frame = window.frame.upgrade();
-            let mut opt_mutex_lock = opt_arc.as_ref().map(|m| m.lock().unwrap());
             let decorations_action = { window.pending_decorations_action.lock().unwrap().take() };
             f(WindowStoreForEach {
                 new_size: window.new_size.take(),
@@ -534,7 +533,7 @@ impl WindowStore {
                 grab_cursor: window.cursor_grab_changed.lock().unwrap().take(),
                 surface: &window.surface,
                 wid: make_wid(&window.surface),
-                frame: opt_mutex_lock.as_mut().map(|m| &mut **m),
+                frame,
                 decorations_action,
             });
             // avoid re-spamming the event
@@ -544,16 +543,15 @@ impl WindowStore {
 
     pub fn for_each_redraw_trigger<F>(&mut self, mut f: F)
     where
-        F: FnMut(bool, bool, WindowId, Option<&mut SWindow<ConceptFrame>>),
+        F: FnMut(bool, bool, WindowId, Option<Arc<Mutex<SWindow<ConceptFrame>>>>),
     {
         for window in &mut self.windows {
-            let opt_arc = window.frame.upgrade();
+            let frame = window.frame.upgrade();
-            let mut opt_mutex_lock = opt_arc.as_ref().map(|m| m.lock().unwrap());
             f(
                 replace(&mut *window.need_refresh.lock().unwrap(), false),
                 replace(&mut *window.need_frame_refresh.lock().unwrap(), false),
                 make_wid(&window.surface),
-                opt_mutex_lock.as_mut().map(|m| &mut **m),
+                frame,
             );
         }
     }