Merge branch 'v0.1.x' into inst-skip_all

tracing-core/src/dispatcher.rs

@@ -131,7 +131,7 @@
 //! [`Dispatch`]: struct.Dispatch.html
 use crate::{
  callsite, span,
- subscriber::{self, Subscriber},
+ subscriber::{self, NoSubscriber, Subscriber},
  Event, LevelFilter, Metadata,
 };
 
@@ -404,7 +404,7 @@ impl Dispatch {
  #[inline]
  pub fn none() -> Self {
  Dispatch {
- subscriber: Arc::new(NoSubscriber),
+ subscriber: Arc::new(NoSubscriber::default()),
  }
  }
 
@@ -661,32 +661,6 @@ where
  }
 }
 
-struct NoSubscriber;
-impl Subscriber for NoSubscriber {
- #[inline]
- fn register_callsite(&self, _: &'static Metadata<'static>) -> subscriber::Interest {
- subscriber::Interest::never()
- }
-
- fn new_span(&self, _: &span::Attributes<'_>) -> span::Id {
- span::Id::from_u64(0xDEAD)
- }
-
- fn event(&self, _event: &Event<'_>) {}
-
- fn record(&self, _span: &span::Id, _values: &span::Record<'_>) {}
-
- fn record_follows_from(&self, _span: &span::Id, _follows: &span::Id) {}
-
- #[inline]
- fn enabled(&self, _metadata: &Metadata<'_>) -> bool {
- false
- }
-
- fn enter(&self, _span: &span::Id) {}
- fn exit(&self, _span: &span::Id) {}
-}
-
 impl Registrar {
  pub(crate) fn try_register(
  &self,
@@ -789,13 +763,13 @@ mod test {
 
  #[test]
  fn dispatch_is() {
- let dispatcher = Dispatch::new(NoSubscriber);
+ let dispatcher = Dispatch::new(NoSubscriber::default());
  assert!(dispatcher.is::<NoSubscriber>());
  }
 
  #[test]
  fn dispatch_downcasts() {
- let dispatcher = Dispatch::new(NoSubscriber);
+ let dispatcher = Dispatch::new(NoSubscriber::default());
  assert!(dispatcher.downcast_ref::<NoSubscriber>().is_some());
  }
 

tracing-core/src/subscriber.rs

@@ -564,6 +564,44 @@ impl Interest {
  }
 }
 
+/// A no-op [`Subscriber`]
+///
+/// [`NoSubscriber`] implements the [`Subscriber`] trait by never being enabled,
+/// never being interested in any callsite, and drops all spans and events.
+#[derive(Debug, Copy, Clone)]
+pub struct NoSubscriber(());
+
+impl Default for NoSubscriber {
+ fn default() -> Self {
+ NoSubscriber(())
+ }
+}
+
+impl Subscriber for NoSubscriber {
+ #[inline]
+ fn register_callsite(&self, _: &'static Metadata<'static>) -> Interest {
+ Interest::never()
+ }
+
+ fn new_span(&self, _: &span::Attributes<'_>) -> span::Id {
+ span::Id::from_u64(0xDEAD)
+ }
+
+ fn event(&self, _event: &Event<'_>) {}
+
+ fn record(&self, _span: &span::Id, _values: &span::Record<'_>) {}
+
+ fn record_follows_from(&self, _span: &span::Id, _follows: &span::Id) {}
+
+ #[inline]
+ fn enabled(&self, _metadata: &Metadata<'_>) -> bool {
+ false
+ }
+
+ fn enter(&self, _span: &span::Id) {}
+ fn exit(&self, _span: &span::Id) {}
+}
+
 impl Subscriber for Box<dyn Subscriber + Send + Sync + 'static> {
  #[inline]
  fn register_callsite(&self, metadata: &'static Metadata<'static>) -> Interest {

tracing-subscriber/src/layer/mod.rs

@@ -1150,7 +1150,7 @@ where
  layer_impl_body! {}
 }
 
-impl<S> Layer<S> for Arc<dyn Layer<S>>
+impl<S> Layer<S> for Arc<dyn Layer<S> + Send + Sync>
 where
  S: Subscriber,
 {
@@ -1165,7 +1165,7 @@ where
  layer_impl_body! {}
 }
 
-impl<S> Layer<S> for Box<dyn Layer<S>>
+impl<S> Layer<S> for Box<dyn Layer<S> + Send + Sync>
 where
  S: Subscriber,
 {