1 files changed, 95 insertions, 0 deletions
diff --git a/helix-view/src/gutter.rs b/helix-view/src/gutter.rs
new file mode 100644
index 00000000..86773c1d
--- /dev/null
+++ b/helix-view/src/gutter.rs
@@ -0,0 +1,95 @@
+use std::fmt::Write;
+
+use crate::{editor::Config, graphics::Style, Document, Theme, View};
+
+pub type GutterFn<'doc> = Box<dyn Fn(usize, bool, &mut String) -> Option<Style> + 'doc>;
+pub type Gutter =
+    for<'doc> fn(&'doc Document, &View, &Theme, &Config, bool, usize) -> GutterFn<'doc>;
+
+pub fn diagnostic<'doc>(
+    doc: &'doc Document,
+    _view: &View,
+    theme: &Theme,
+    _config: &Config,
+    _is_focused: bool,
+    _width: usize,
+) -> GutterFn<'doc> {
+    let warning = theme.get("warning");
+    let error = theme.get("error");
+    let info = theme.get("info");
+    let hint = theme.get("hint");
+    let diagnostics = doc.diagnostics();
+
+    Box::new(move |line: usize, _selected: bool, out: &mut String| {
+        use helix_core::diagnostic::Severity;
+        if let Some(diagnostic) = diagnostics.iter().find(|d| d.line == line) {
+            write!(out, "●").unwrap();
+            return Some(match diagnostic.severity {
+                Some(Severity::Error) => error,
+                Some(Severity::Warning) | None => warning,
+                Some(Severity::Info) => info,
+                Some(Severity::Hint) => hint,
+            });
+        }
+        None
+    })
+}
+
+pub fn line_number<'doc>(
+    doc: &'doc Document,
+    view: &View,
+    theme: &Theme,
+    config: &Config,
+    is_focused: bool,
+    width: usize,
+) -> GutterFn<'doc> {
+    let text = doc.text().slice(..);
+    let last_line = view.last_line(doc);
+    // Whether to draw the line number for the last line of the
+    // document or not.  We only draw it if it's not an empty line.
+    let draw_last = text.line_to_byte(last_line) < text.len_bytes();
+
+    let linenr = theme.get("ui.linenr");
+    let linenr_select: Style = theme.try_get("ui.linenr.selected").unwrap_or(linenr);
+
+    let current_line = doc
+        .text()
+        .char_to_line(doc.selection(view.id).primary().cursor(text));
+
+    let config = config.line_number;
+
+    Box::new(move |line: usize, selected: bool, out: &mut String| {
+        if line == last_line && !draw_last {
+            write!(out, "{:>1$}", '~', width).unwrap();
+            Some(linenr)
+        } else {
+            use crate::editor::LineNumber;
+            let line = match config {
+                LineNumber::Absolute => line + 1,
+                LineNumber::Relative => {
+                    if current_line == line {
+                        line + 1
+                    } else {
+                        abs_diff(current_line, line)
+                    }
+                }
+            };
+            let style = if selected && is_focused {
+                linenr_select
+            } else {
+                linenr
+            };
+            write!(out, "{:>1$}", line, width).unwrap();
+            Some(style)
+        }
+    })
+}
+
+#[inline(always)]
+const fn abs_diff(a: usize, b: usize) -> usize {
+    if a > b {
+        a - b
+    } else {
+        b - a
+    }
+}