v0.1.3-pre.005

crates/ksp-logging-lib/src/writer.rs

@@ -1,5 +1,5 @@
 // file: crates/ksp-logging-lib/src/writer.rs
-// version: 1
+// version: 2
 
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 enum StripAnsiState {
@@ -100,6 +100,96 @@ impl<W> StripAnsiWriter<W> {
     }
 }
 
+#[derive(Clone)]
+pub(crate) struct RouteMakeWriter<W> {
+    inner: W,
+    filter: crate::OutputFilter,
+}
+
+impl<W> RouteMakeWriter<W> {
+    pub(crate) fn new(inner: W, filter: crate::OutputFilter) -> Self {
+        return Self { inner, filter };
+    }
+}
+
+pub(crate) enum RoutedWriter<W> {
+    Enabled(W),
+    Disabled,
+}
+
+impl<W> std::io::Write for RoutedWriter<W>
+where
+    W: std::io::Write,
+{
+    fn write(&mut self, buffer: &[u8]) -> std::io::Result<usize> {
+        return match self {
+            Self::Enabled(writer) => std::io::Write::write(writer, buffer),
+            Self::Disabled => std::result::Result::Ok(buffer.len()),
+        };
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        return match self {
+            Self::Enabled(writer) => std::io::Write::flush(writer),
+            Self::Disabled => std::result::Result::Ok(()),
+        };
+    }
+}
+
+impl<'writer, W> tracing_subscriber::fmt::MakeWriter<'writer> for RouteMakeWriter<W>
+where
+    W: tracing_subscriber::fmt::MakeWriter<'writer>,
+{
+    type Writer = RoutedWriter<W::Writer>;
+
+    fn make_writer(&'writer self) -> Self::Writer {
+        return RoutedWriter::Enabled(tracing_subscriber::fmt::MakeWriter::make_writer(&self.inner));
+    }
+
+    fn make_writer_for(&'writer self, metadata: &tracing::Metadata<'_>) -> Self::Writer {
+        if metadata_matches_filter(metadata, &self.filter) {
+            return RoutedWriter::Enabled(tracing_subscriber::fmt::MakeWriter::make_writer_for(&self.inner, metadata));
+        }
+        return RoutedWriter::Disabled;
+    }
+}
+
+fn metadata_matches_filter(metadata: &tracing::Metadata<'_>, filter: &crate::OutputFilter) -> bool {
+    if !level_is_enabled(metadata.level(), filter.level()) {
+        return false;
+    }
+    return filter.targets().iter().any(|selector| -> bool {
+        return selector == "*" || metadata.target().starts_with(selector.as_str());
+    });
+}
+
+fn level_is_enabled(level: &tracing::Level, filter: crate::LogFilterLevel) -> bool {
+    return match filter {
+        crate::LogFilterLevel::Off => false,
+        crate::LogFilterLevel::Error => level_rank(level) <= 1,
+        crate::LogFilterLevel::Warn => level_rank(level) <= 2,
+        crate::LogFilterLevel::Info => level_rank(level) <= 3,
+        crate::LogFilterLevel::Debug => level_rank(level) <= 4,
+        crate::LogFilterLevel::Trace => level_rank(level) <= 5,
+    };
+}
+
+fn level_rank(level: &tracing::Level) -> u8 {
+    if level == &tracing::Level::ERROR {
+        return 1;
+    }
+    if level == &tracing::Level::WARN {
+        return 2;
+    }
+    if level == &tracing::Level::INFO {
+        return 3;
+    }
+    if level == &tracing::Level::DEBUG {
+        return 4;
+    }
+    return 5;
+}
+
 #[cfg(test)]
 #[path = "../unit_tests/writer.rs"]
 mod tests;