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use tracing::Subscriber;
use tracing_subscriber::filter::Targets;
use tracing_subscriber::prelude::*;
use tracing_subscriber::Layer;
#[test]
fn downcast_ref_to_inner_layer_and_filter() {
// Test that a filtered layer gives downcast_ref access to
// both the layer and the filter.
struct WrappedLayer;
impl<S> Layer<S> for WrappedLayer
where
S: Subscriber,
S: for<'lookup> tracing_subscriber::registry::LookupSpan<'lookup>,
{
}
let layer = WrappedLayer;
let filter = Targets::new().with_default(tracing::Level::INFO);
let registry = tracing_subscriber::registry().with(layer.with_filter(filter));
let dispatch = tracing::dispatcher::Dispatch::new(registry);
// The filter is available
assert!(dispatch.downcast_ref::<Targets>().is_some());
// The wrapped layer is available
assert!(dispatch.downcast_ref::<WrappedLayer>().is_some());
}
#[test]
fn forward_downcast_raw_to_layer() {
// Test that a filtered layer still gives its wrapped layer a chance to
// return a custom struct from downcast_raw.
// https://github.com/tokio-rs/tracing/issues/1618
struct WrappedLayer {
with_context: WithContext,
}
struct WithContext;
impl<S> Layer<S> for WrappedLayer
where
S: Subscriber,
S: for<'lookup> tracing_subscriber::registry::LookupSpan<'lookup>,
{
unsafe fn downcast_raw(&self, id: std::any::TypeId) -> Option<*const ()> {
match id {
id if id == std::any::TypeId::of::<Self>() => Some(self as *const _ as *const ()),
id if id == std::any::TypeId::of::<WithContext>() => {
Some(&self.with_context as *const _ as *const ())
}
_ => None,
}
}
}
let layer = WrappedLayer {
with_context: WithContext,
};
let filter = Targets::new().with_default(tracing::Level::INFO);
let registry = tracing_subscriber::registry().with(layer.with_filter(filter));
let dispatch = tracing::dispatcher::Dispatch::new(registry);
// Types from a custom implementation of `downcast_raw` are available
assert!(dispatch.downcast_ref::<WithContext>().is_some());
}
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