Replace spawn_unchecked with static lifetimes

These things don't need to hold references, so this gets rid of some
nasty c ode.

src/context.rs

@@ -90,14 +90,15 @@ pub trait GuiContext {
 /// thread.
 ///
 /// This is never used generically, but having this as a trait will cause any missing functions on
-/// an implementation to show up as compiler errors even when using a different platform.
+/// an implementation to show up as compiler errors even when using a different platform. And since
+/// the tasks and executor will be sent to a thread, they need to have static lifetimes.
 ///
 /// TODO: At some point rethink the design to make it possible to have a singleton message queue for
 ///       all instances of a plugin.
 pub(crate) trait EventLoop<T, E>
 where
-    T: Send,
+    T: Send + 'static,
-    E: MainThreadExecutor<T>,
+    E: MainThreadExecutor<T> + 'static,
 {
     /// Create and start a new event loop. The thread this is called on will be designated as the
     /// main thread, so this should be called when constructing the wrapper.

src/context/linux.rs

@@ -24,7 +24,6 @@ use std::thread::{self, JoinHandle, ThreadId};
 
 use super::{EventLoop, MainThreadExecutor};
 use crate::nih_log;
-use crate::util::ThreadSpawnUnchecked;
 
 /// See [super::EventLoop].
 pub(crate) struct LinuxEventLoop<T, E> {
@@ -56,8 +55,8 @@ enum Message<T> {
 
 impl<T, E> EventLoop<T, E> for LinuxEventLoop<T, E>
 where
-    T: Send,
+    T: Send + 'static,
-    E: MainThreadExecutor<T>,
+    E: MainThreadExecutor<T> + 'static,
 {
     fn new_and_spawn(executor: Weak<E>) -> Self {
         let (sender, receiver) = channel::bounded(super::TASK_QUEUE_CAPACITY);
@@ -66,17 +65,12 @@ where
             executor: executor.clone(),
             main_thread_id: thread::current().id(),
             // With our drop implementation we guarentee that this thread never outlives this struct
-            worker_thread: Some(unsafe {
+            worker_thread: Some(
                 thread::Builder::new()
                     .name(String::from("worker"))
-                    // The worker thread gets joined when this struct gets dropped, and if this
+                    .spawn(move || worker_thread(receiver, executor))
-                    // struct never gets dropped it just sits there idly. Panics cannot be unwound,
+                    .expect("Could not spawn worker thread"),
-                    // but in plugin-land we have bigger worries than that.
+            ),
-                    // This is the same as the `.spawn_unchecked()` function, but without requiring
-                    // a nightly compiler.
-                    .spawn_unchecked_2(move || worker_thread(receiver, executor))
-                    .expect("Could not spawn worker thread")
-            }),
             worker_thread_channel: sender,
         }
     }

src/util.rs

@@ -41,28 +41,6 @@ pub fn midi_note_to_freq(pitch: u8) -> f32 {
     2.0f32.powf((pitch as f32 - 69.0) / 12.0) * 440.0
 }
 
-/// A version of [std::thread::Builder::spawn_unchecked()] that works on the stable compiler.
-/// Implementation courtesy of Yandros on the Rust Discord.
-pub(crate) trait ThreadSpawnUnchecked {
-    unsafe fn spawn_unchecked_2<F, R>(self, f: F) -> std::io::Result<std::thread::JoinHandle<R>>
-    where
-        F: FnOnce() -> R + Send,
-        R: 'static + Send;
-}
-
-impl ThreadSpawnUnchecked for std::thread::Builder {
-    unsafe fn spawn_unchecked_2<F, R>(self, f: F) -> std::io::Result<std::thread::JoinHandle<R>>
-    where
-        F: FnOnce() -> R + Send,
-        R: 'static + Send,
-    {
-        let f: Box<dyn '_ + FnOnce() -> R + Send> = Box::new(f);
-        // SAFETY: same-layout since only a lifetime difference
-        let f: Box<dyn 'static + FnOnce() -> R + Send> = std::mem::transmute(f);
-        self.spawn(f)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;