Preserve current position when new items are added to a buffer

src/buffers/log.rs

@@ -32,7 +32,7 @@ use crate::widgets::Prerender;
 const MAX_MEM_LOG_LINES: usize = 1000;
 
 pub struct LogBuffer {
-  lines: VecDeque<(String, Prerender)>,
+  lines: VecDeque<(u64, String, Prerender)>,
   receiver: UnboundedReceiver<String>,
 }
 
@@ -73,17 +73,29 @@ impl Buffer for LogBuffer {
     if self.lines.len() >= MAX_MEM_LOG_LINES {
       self.lines.pop_front();
     }
-    self.lines.push_back((line, Prerender::new()));
+    let line_id = self
+      .lines
+      .back()
+      .map(|(last_id, _, _)| last_id + 1)
+      .unwrap_or(0);
+    self.lines.push_back((line_id, line, Prerender::new()));
   }
 
   fn content<'a>(&'a self) -> Box<dyn ExactSizeIterator<Item = BufferItem<'a>> + 'a> {
     use ansi_to_tui::IntoText;
-    Box::new(self.lines.iter().rev().map(|(line, prerender)| BufferItem {
-      content: BufferItemContent::Text(line.clone().into_text().unwrap_or_else(|e| {
-        tracing::error!("Could not convert line from ANSI codes to ratatui: {}", e);
-        Text::raw(line)
-      })),
-      prerender,
-    }))
+    Box::new(
+      self
+        .lines
+        .iter()
+        .rev()
+        .map(|(line_id, line, prerender)| BufferItem {
+          content: BufferItemContent::Text(line.clone().into_text().unwrap_or_else(|e| {
+            tracing::error!("Could not convert line from ANSI codes to ratatui: {}", e);
+            Text::raw(line)
+          })),
+          prerender,
+          unique_id: Some(*line_id),
+        }),
+    )
   }
 }