add console log event format hook

Signed-off-by: Jason Volk <jason@zemos.net>

src/core/log/console.rs

@@ -0,0 +1,94 @@
+use tracing::{
+	field::{Field, Visit},
+	Event, Level, Subscriber,
+};
+use tracing_subscriber::{
+	field::RecordFields,
+	fmt,
+	fmt::{
+		format::{Compact, DefaultVisitor, Format, Full, Pretty, Writer},
+		FmtContext, FormatEvent, FormatFields,
+	},
+	registry::LookupSpan,
+};
+
+use crate::{Config, Result};
+
+pub struct ConsoleFormat {
+	_compact: Format<Compact>,
+	full: Format<Full>,
+	pretty: Format<Pretty>,
+}
+
+struct ConsoleVisitor<'a> {
+	visitor: DefaultVisitor<'a>,
+}
+
+impl ConsoleFormat {
+	#[must_use]
+	pub fn new(config: &Config) -> Self {
+		Self {
+			_compact: fmt::format().compact(),
+
+			full: Format::<Full>::default()
+				.with_thread_ids(config.log_thread_ids)
+				.with_ansi(config.log_colors),
+
+			pretty: fmt::format()
+				.pretty()
+				.with_ansi(config.log_colors)
+				.with_thread_names(true)
+				.with_thread_ids(true)
+				.with_target(true)
+				.with_file(true)
+				.with_line_number(true)
+				.with_source_location(true),
+		}
+	}
+}
+
+impl<S, N> FormatEvent<S, N> for ConsoleFormat
+where
+	S: Subscriber + for<'a> LookupSpan<'a>,
+	N: for<'a> FormatFields<'a> + 'static,
+{
+	fn format_event(
+		&self,
+		ctx: &FmtContext<'_, S, N>,
+		writer: Writer<'_>,
+		event: &Event<'_>,
+	) -> Result<(), std::fmt::Error> {
+		let is_debug =
+			cfg!(debug_assertions) && event.fields().any(|field| field.name() == "_debug");
+
+		match *event.metadata().level() {
+			| Level::ERROR if !is_debug => self.pretty.format_event(ctx, writer, event),
+			| _ => self.full.format_event(ctx, writer, event),
+		}
+	}
+}
+
+impl<'writer> FormatFields<'writer> for ConsoleFormat {
+	fn format_fields<R>(&self, writer: Writer<'writer>, fields: R) -> Result<(), std::fmt::Error>
+	where
+		R: RecordFields,
+	{
+		let mut visitor = ConsoleVisitor {
+			visitor: DefaultVisitor::<'_>::new(writer, true),
+		};
+
+		fields.record(&mut visitor);
+
+		Ok(())
+	}
+}
+
+impl Visit for ConsoleVisitor<'_> {
+	fn record_debug(&mut self, field: &Field, value: &dyn std::fmt::Debug) {
+		if field.name().starts_with('_') {
+			return;
+		}
+
+		self.visitor.record_debug(field, value);
+	}
+}