global: snapshot

crates/brk_logger/src/hook.rs

@@ -0,0 +1,30 @@
+use std::{fmt::Write, sync::OnceLock};
+
+use tracing::{Event, Subscriber, field::Field};
+
+type LogHook = Box<dyn Fn(&str) + Send + Sync>;
+
+pub static LOG_HOOK: OnceLock<LogHook> = OnceLock::new();
+
+pub struct HookLayer;
+
+impl<S: Subscriber> tracing_subscriber::Layer<S> for HookLayer {
+    fn on_event(&self, event: &Event<'_>, _: tracing_subscriber::layer::Context<'_, S>) {
+        if let Some(hook) = LOG_HOOK.get() {
+            let mut msg = String::new();
+            event.record(&mut MessageVisitor(&mut msg));
+            hook(&msg);
+        }
+    }
+}
+
+struct MessageVisitor<'a>(&'a mut String);
+
+impl tracing::field::Visit for MessageVisitor<'_> {
+    fn record_debug(&mut self, field: &Field, value: &dyn std::fmt::Debug) {
+        if field.name() == "message" {
+            self.0.clear();
+            let _ = write!(self.0, "{value:?}");
+        }
+    }
+}