Fixing Gooey compilation on MacOS

After trying to run Gooey again on my Mac for the first time in a few
weeks, I found that I ran into the Condvar issue again. Rather than
pasting AssertUnwindSafe in those files, I've both reported the
discrepency in unwind safety (rust-lang/rust#118009) and moved the
workaround into a type that only uses AssertUnwindsafe when compiling
for Apple.

src/animation.rs

@@ -44,7 +44,7 @@ use std::fmt::{Debug, Display};
 use std::ops::{ControlFlow, Deref, Div, Mul};
 use std::panic::{RefUnwindSafe, UnwindSafe};
 use std::str::FromStr;
-use std::sync::{Arc, Condvar, Mutex, MutexGuard, OnceLock};
+use std::sync::{Arc, Mutex, MutexGuard, OnceLock};
 use std::thread;
 use std::time::{Duration, Instant};
 
@@ -57,11 +57,11 @@ use kludgine::Color;
 
 use crate::animation::easings::Linear;
 use crate::styles::{Component, RequireInvalidation};
-use crate::utils::IgnorePoison;
+use crate::utils::{IgnorePoison, UnwindsafeCondvar};
 use crate::value::Dynamic;
 
 static ANIMATIONS: Mutex<Animating> = Mutex::new(Animating::new());
-static NEW_ANIMATIONS: Condvar = Condvar::new();
+static NEW_ANIMATIONS: UnwindsafeCondvar = UnwindsafeCondvar::new();
 
 fn thread_state() -> MutexGuard<'static, Animating> {
     static THREAD: OnceLock<()> = OnceLock::new();

src/tick.rs

@@ -1,13 +1,13 @@
 use std::collections::HashSet;
 use std::sync::atomic::{AtomicUsize, Ordering};
-use std::sync::{Arc, Condvar, Mutex, MutexGuard};
+use std::sync::{Arc, Mutex, MutexGuard};
 use std::time::{Duration, Instant};
 
 use kludgine::app::winit::event::KeyEvent;
 use kludgine::app::winit::keyboard::Key;
 
 use crate::context::WidgetContext;
-use crate::utils::IgnorePoison;
+use crate::utils::{IgnorePoison, UnwindsafeCondvar};
 use crate::value::Dynamic;
 use crate::widget::{EventHandling, HANDLED, IGNORED};
 
@@ -65,7 +65,7 @@ impl Tick {
                 input: InputState::default(),
             }),
             period: tick_every,
-            sync: Condvar::new(),
+            sync: UnwindsafeCondvar::new(),
             rendered_frame: AtomicUsize::new(0),
             tick_number: Dynamic::default(),
         });
@@ -117,7 +117,7 @@ pub struct InputState {
 struct TickData {
     state: Mutex<TickState>,
     period: Duration,
-    sync: Condvar,
+    sync: UnwindsafeCondvar,
     rendered_frame: AtomicUsize,
     tick_number: Dynamic<u64>,
 }

src/utils.rs

@@ -1,9 +1,40 @@
 use std::ops::Deref;
-use std::sync::{OnceLock, PoisonError};
+use std::sync::{Condvar, OnceLock, PoisonError};
 
 use kludgine::app::winit::event::Modifiers;
 use kludgine::app::winit::keyboard::ModifiersState;
 
+/// This [`Condvar`] is a wrapper that on Mac OS/iOS asserts unwind safety. On
+/// all other platforms, this is a transparent wrapper around `Condvar`. See
+/// <https://github.com/rust-lang/rust/issues/118009> for more information.
+#[derive(Debug, Default)]
+pub struct UnwindsafeCondvar(
+    #[cfg(any(target_os = "ios", target_os = "macos"))] std::panic::AssertUnwindSafe<Condvar>,
+    #[cfg(not(any(target_os = "ios", target_os = "macos")))] Condvar,
+);
+
+impl Deref for UnwindsafeCondvar {
+    type Target = Condvar;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl UnwindsafeCondvar {
+    pub const fn new() -> Self {
+        #[cfg(any(target_os = "ios", target_os = "macos"))]
+        {
+            Self(AssertUnwindSafe(Condvar::new()))
+        }
+
+        #[cfg(not(any(target_os = "ios", target_os = "macos")))]
+        {
+            Self(Condvar::new())
+        }
+    }
+}
+
 /// Invokes the provided macro with a pattern that can be matched using this
 /// `macro_rules!` expression: `$($type:ident $field:tt $var:ident),+`, where `$type` is an
 /// identifier to use for the generic parameter and `$field` is the field index

src/value.rs

@@ -4,9 +4,8 @@ use std::cell::Cell;
 use std::fmt::{Debug, Display};
 use std::future::Future;
 use std::ops::{Deref, DerefMut};
-use std::panic::AssertUnwindSafe;
 use std::str::FromStr;
-use std::sync::{Arc, Condvar, Mutex, MutexGuard, TryLockError};
+use std::sync::{Arc, Mutex, MutexGuard, TryLockError};
 use std::task::{Poll, Waker};
 use std::thread::ThreadId;
 
@@ -15,7 +14,7 @@ use intentional::Assert;
 
 use crate::animation::{DynamicTransition, LinearInterpolate};
 use crate::context::{WidgetContext, WindowHandle};
-use crate::utils::{IgnorePoison, WithClone};
+use crate::utils::{IgnorePoison, UnwindsafeCondvar, WithClone};
 use crate::widget::{WidgetId, WidgetInstance};
 use crate::widgets::Switcher;
 
@@ -40,7 +39,7 @@ impl<T> Dynamic<T> {
                 widgets: AHashSet::new(),
             }),
             during_callback_state: Mutex::default(),
-            sync: AssertUnwindSafe(Condvar::new()),
+            sync: UnwindsafeCondvar::default(),
         }))
     }
 
@@ -553,10 +552,7 @@ struct LockState {
 struct DynamicData<T> {
     state: Mutex<State<T>>,
     during_callback_state: Mutex<Option<LockState>>,
-
-    // The AssertUnwindSafe is only needed on Mac. For some reason on
-    // Mac OS, Condvar isn't RefUnwindSafe.
-    sync: AssertUnwindSafe<Condvar>,
+    sync: UnwindsafeCondvar,
 }
 
 impl<T> DynamicData<T> {