Never mind, tracing layers must be Sync, so you can't hold a cell in …

…there—go back to TLS, but use the new VecCell abstraction

Signed-off-by: Alex Saveau <[email protected]>

tracing-tracy/src/lib.rs

@@ -72,12 +72,17 @@ thread_local! {
  const { UnsafeCell::new(VecDeque::new()) };
 }
 
-#[derive(Default)]
 struct VecCell<T> {
  items: UnsafeCell<Vec<T>>,
 }
 
 impl<T> VecCell<T> {
+ const fn new() -> Self {
+ Self {
+ items: UnsafeCell::new(Vec::new()),
+ }
+ }
+
  fn push(&self, item: T) {
  unsafe { &mut *self.items.get() }.push(item);
  }
@@ -88,12 +93,11 @@ impl<T> VecCell<T> {
 }
 
 /// A tracing layer that collects data in Tracy profiling format.
+#[derive(Clone)]
 pub struct TracyLayer<F = DefaultFields> {
  fmt: F,
  stack_depth: u16,
  client: Client,
-
- buf_cache: VecCell<String>,
 }
 
 impl TracyLayer<DefaultFields> {
@@ -106,8 +110,6 @@ impl TracyLayer<DefaultFields> {
  fmt: DefaultFields::default(),
  stack_depth: 0,
  client: Client::start(),
-
- buf_cache: VecCell::default(),
  }
  }
 }
@@ -131,7 +133,6 @@ impl<F> TracyLayer<F> {
  fmt,
  stack_depth: self.stack_depth,
  client: self.client,
- buf_cache: self.buf_cache,
  }
  }
 
@@ -195,31 +196,37 @@ where
  }
 
  fn on_event(&self, event: &Event, _: Context<'_, S>) {
- let mut buf = self.buf_cache.pop().unwrap_or_default();
- let mut visitor = TracyEventFieldVisitor {
- dest: &mut buf,
- first: true,
- frame_mark: false,
- };
-
- event.record(&mut visitor);
- if !visitor.first {
- self.client.message(
- self.truncate_to_length(
- visitor.dest,
- "",
- "",
- "event message is too long and was truncated",
- ),
- self.stack_depth,
- );
- }
- if visitor.frame_mark {
- self.client.frame_mark();
+ thread_local! {
+ static CACHE: VecCell<String> = const { VecCell::new() };
  }
 
- buf.clear();
- self.buf_cache.push(buf)
+ CACHE.with(|cache| {
+ let mut buf = cache.pop().unwrap_or_default();
+ let mut visitor = TracyEventFieldVisitor {
+ dest: &mut buf,
+ first: true,
+ frame_mark: false,
+ };
+
+ event.record(&mut visitor);
+ if !visitor.first {
+ self.client.message(
+ self.truncate_to_length(
+ visitor.dest,
+ "",
+ "",
+ "event message is too long and was truncated",
+ ),
+ self.stack_depth,
+ );
+ }
+ if visitor.frame_mark {
+ self.client.frame_mark();
+ }
+
+ buf.clear();
+ cache.push(buf);
+ });
  }
 
  fn on_enter(&self, id: &Id, ctx: Context<S>) {