Wrap back to zero after a specific number of indentation levels (#15)

Author: oli-obk

examples/wraparound.rs

@@ -0,0 +1,30 @@
+use tracing::{instrument, warn};
+use tracing_subscriber::{layer::SubscriberExt, registry::Registry};
+use tracing_tree::HierarchicalLayer;
+
+fn main() {
+    let layer = HierarchicalLayer::default()
+        .with_indent_lines(true)
+        .with_indent_amount(2)
+        .with_thread_names(true)
+        .with_thread_ids(true)
+        .with_targets(true)
+        .with_wraparound(5);
+
+    let subscriber = Registry::default().with(layer);
+    tracing::subscriber::set_global_default(subscriber).unwrap();
+
+    recurse(0);
+}
+
+#[instrument]
+fn recurse(i: usize) {
+    warn!("boop");
+    if i > 20 {
+        warn!("bop");
+        return;
+    } else {
+        recurse(i + 1);
+    }
+    warn!("bop");
+}

src/format.rs

@@ -26,6 +26,8 @@ pub struct Config {
     pub render_thread_ids: bool,
     /// Whether to show thread names.
     pub render_thread_names: bool,
+    /// Specifies after how many indentation levels we will wrap back around to zero
+    pub wraparound: usize,
 }
 
 impl Config {
@@ -58,6 +60,10 @@ impl Config {
         }
     }
 
+    pub fn with_wraparound(self, wraparound: usize) -> Self {
+        Self { wraparound, ..self }
+    }
+
     pub(crate) fn prefix(&self) -> String {
         let mut buf = String::new();
         if self.render_thread_ids {
@@ -90,6 +96,7 @@ impl Default for Config {
             targets: false,
             render_thread_ids: false,
             render_thread_names: false,
+            wraparound: usize::max_value(),
         }
     }
 }
@@ -123,7 +130,7 @@ impl Buffers {
         indent_block(
             &mut self.current_buf,
             &mut self.indent_buf,
-            indent,
+            indent % config.wraparound,
             config.indent_amount,
             config.indent_lines,
             &config.prefix(),

src/lib.rs

@@ -139,6 +139,16 @@ where
         }
     }
 
+    /// Resets the indentation to zero after `wraparound` indentation levels.
+    /// This is helpful if you expect very deeply nested spans as otherwise the indentation
+    /// just runs out of your screen.
+    pub fn with_wraparound(self, wraparound: usize) -> Self {
+        Self {
+            config: self.config.with_wraparound(wraparound),
+            ..self
+        }
+    }
+
     fn styled(&self, style: Style, text: impl AsRef<str>) -> String {
         if self.config.ansi {
             style.paint(text.as_ref()).to_string()