Make gutters configurable (#1967)

* config option line numbers none

* view tests

* added tests

* doc

* comment

* Make gutters configurable

* docu

* docu

* rm none docu

* order

* order

* precedence

* simpler

* rm todo

* fixed clippy

* order

* double quotes

* only allow diagnostics and line-numbers

* tests

* docu

* format

* rm short variant and more docu

* performance improvements

* typo

* rename

6 files changed, 110 insertions, 25 deletions

diff --git a/book/src/configuration.md b/book/src/configuration.md
index dae46176..3ec2bedb 100644
--- a/book/src/configuration.md
+++ b/book/src/configuration.md
@@ -37,6 +37,7 @@ hidden = false
 | `scroll-lines` | Number of lines to scroll per scroll wheel step. | `3` |
 | `shell` | Shell to use when running external commands. | Unix: `["sh", "-c"]`<br/>Windows: `["cmd", "/C"]` |
 | `line-number` | Line number display: `absolute` simply shows each line's number, while `relative` shows the distance from the current line. When unfocused or in insert mode, `relative` will still show absolute line numbers. | `absolute` |
+| `gutters` | Gutters to display: Available are `diagnostics` and `line-numbers`, note that `diagnostics` also includes other features like breakpoints | `["diagnostics", "line-numbers"]` |
 | `auto-completion` | Enable automatic pop up of auto-completion. | `true` |
 | `idle-timeout` | Time in milliseconds since last keypress before idle timers trigger. Used for autocompletion, set to 0 for instant. | `400` |
 | `completion-trigger-len` | The min-length of word under cursor to trigger autocompletion | `2` |
diff --git a/helix-term/src/ui/editor.rs b/helix-term/src/ui/editor.rs
index 564605de..459a8c87 100644
--- a/helix-term/src/ui/editor.rs
+++ b/helix-term/src/ui/editor.rs
@@ -466,7 +466,7 @@ impl EditorView {
         // avoid lots of small allocations by reusing a text buffer for each line
         let mut text = String::with_capacity(8);
 
-        for (constructor, width) in view.gutters() {
+        for (constructor, width) in &view.gutters {
             let gutter = constructor(editor, doc, view, theme, is_focused, *width);
             text.reserve(*width); // ensure there's enough space for the gutter
             for (i, line) in (view.offset.row..(last_line + 1)).enumerate() {
diff --git a/helix-view/src/editor.rs b/helix-view/src/editor.rs
index 76fc6713..dd805c00 100644
--- a/helix-view/src/editor.rs
+++ b/helix-view/src/editor.rs
@@ -117,6 +117,8 @@ pub struct Config {
     pub shell: Vec<String>,
     /// Line number mode.
     pub line_number: LineNumber,
+    /// Gutters. Default ["diagnostics", "line-numbers"]
+    pub gutters: Vec<GutterType>,
     /// Middle click paste support. Defaults to true.
     pub middle_click_paste: bool,
     /// Automatic insertion of pairs to parentheses, brackets,
@@ -238,6 +240,27 @@ impl std::str::FromStr for LineNumber {
     }
 }
 
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "kebab-case")]
+pub enum GutterType {
+    /// Show diagnostics and other features like breakpoints
+    Diagnostics,
+    /// Show line numbers
+    LineNumbers,
+}
+
+impl std::str::FromStr for GutterType {
+    type Err = anyhow::Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s.to_lowercase().as_str() {
+            "diagnostics" => Ok(Self::Diagnostics),
+            "line-numbers" => Ok(Self::LineNumbers),
+            _ => anyhow::bail!("Gutter type can only be `diagnostics` or `line-numbers`."),
+        }
+    }
+}
+
 impl Default for Config {
     fn default() -> Self {
         Self {
@@ -250,6 +273,7 @@ impl Default for Config {
                 vec!["sh".to_owned(), "-c".to_owned()]
             },
             line_number: LineNumber::Absolute,
+            gutters: vec![GutterType::Diagnostics, GutterType::LineNumbers],
             middle_click_paste: true,
             auto_pairs: AutoPairConfig::default(),
             auto_completion: true,
@@ -579,7 +603,7 @@ impl Editor {
                 return;
             }
             Action::HorizontalSplit | Action::VerticalSplit => {
-                let view = View::new(id);
+                let view = View::new(id, self.config().gutters.clone());
                 let view_id = self.tree.split(
                     view,
                     match action {
@@ -701,7 +725,7 @@ impl Editor {
                 .map(|(&doc_id, _)| doc_id)
                 .next()
                 .unwrap_or_else(|| self.new_document(Document::default()));
-            let view = View::new(doc_id);
+            let view = View::new(doc_id, self.config().gutters.clone());
             let view_id = self.tree.insert(view);
             let doc = self.documents.get_mut(&doc_id).unwrap();
             doc.selections.insert(view_id, Selection::point(0));
diff --git a/helix-view/src/gutter.rs b/helix-view/src/gutter.rs
index 7327ed1a..06ce1b2e 100644
--- a/helix-view/src/gutter.rs
+++ b/helix-view/src/gutter.rs
@@ -39,7 +39,7 @@ pub fn diagnostic<'doc>(
     })
 }
 
-pub fn line_number<'doc>(
+pub fn line_numbers<'doc>(
     editor: &'doc Editor,
     doc: &'doc Document,
     view: &View,
diff --git a/helix-view/src/tree.rs b/helix-view/src/tree.rs
index 99cbe0f9..b068f4c7 100644
--- a/helix-view/src/tree.rs
+++ b/helix-view/src/tree.rs
@@ -568,6 +568,7 @@ impl<'a> Iterator for Traverse<'a> {
 #[cfg(test)]
 mod test {
     use super::*;
+    use crate::editor::GutterType;
     use crate::DocumentId;
 
     #[test]
@@ -578,22 +579,34 @@ mod test {
             width: 180,
             height: 80,
         });
-        let mut view = View::new(DocumentId::default());
+        let mut view = View::new(
+            DocumentId::default(),
+            vec![GutterType::Diagnostics, GutterType::LineNumbers],
+        );
         view.area = Rect::new(0, 0, 180, 80);
         tree.insert(view);
 
         let l0 = tree.focus;
-        let view = View::new(DocumentId::default());
+        let view = View::new(
+            DocumentId::default(),
+            vec![GutterType::Diagnostics, GutterType::LineNumbers],
+        );
         tree.split(view, Layout::Vertical);
         let r0 = tree.focus;
 
         tree.focus = l0;
-        let view = View::new(DocumentId::default());
+        let view = View::new(
+            DocumentId::default(),
+            vec![GutterType::Diagnostics, GutterType::LineNumbers],
+        );
         tree.split(view, Layout::Horizontal);
         let l1 = tree.focus;
 
         tree.focus = l0;
-        let view = View::new(DocumentId::default());
+        let view = View::new(
+            DocumentId::default(),
+            vec![GutterType::Diagnostics, GutterType::LineNumbers],
+        );
         tree.split(view, Layout::Vertical);
         let l2 = tree.focus;
 
diff --git a/helix-view/src/view.rs b/helix-view/src/view.rs
index c6ae0c56..7cf88c2e 100644
--- a/helix-view/src/view.rs
+++ b/helix-view/src/view.rs
@@ -11,6 +11,8 @@ use helix_core::{
     visual_coords_at_pos, Position, RopeSlice, Selection,
 };
 
+use std::fmt;
+
 type Jump = (DocumentId, Selection);
 
 #[derive(Debug, Clone)]
@@ -64,17 +66,11 @@ impl JumpList {
     }
 }
 
-const GUTTERS: &[(Gutter, usize)] = &[
-    (gutter::diagnostics_or_breakpoints, 1),
-    (gutter::line_number, 5),
-];
-
-#[derive(Debug)]
 pub struct View {
     pub id: ViewId,
-    pub doc: DocumentId,
     pub offset: Position,
     pub area: Rect,
+    pub doc: DocumentId,
     pub jumps: JumpList,
     /// the last accessed file before the current one
     pub last_accessed_doc: Option<DocumentId>,
@@ -85,10 +81,29 @@ pub struct View {
     pub last_modified_docs: [Option<DocumentId>; 2],
     /// used to store previous selections of tree-sitter objecs
     pub object_selections: Vec<Selection>,
+    pub gutters: Vec<(Gutter, usize)>,
+}
+
+impl fmt::Debug for View {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("View")
+            .field("id", &self.id)
+            .field("area", &self.area)
+            .field("doc", &self.doc)
+            .finish()
+    }
 }
 
 impl View {
-    pub fn new(doc: DocumentId) -> Self {
+    pub fn new(doc: DocumentId, gutter_types: Vec<crate::editor::GutterType>) -> Self {
+        let mut gutters: Vec<(Gutter, usize)> = vec![];
+        use crate::editor::GutterType;
+        for gutter_type in &gutter_types {
+            match gutter_type {
+                GutterType::Diagnostics => gutters.push((gutter::diagnostics_or_breakpoints, 1)),
+                GutterType::LineNumbers => gutters.push((gutter::line_numbers, 5)),
+            }
+        }
         Self {
             id: ViewId::default(),
             doc,
@@ -98,17 +113,14 @@ impl View {
             last_accessed_doc: None,
             last_modified_docs: [None, None],
             object_selections: Vec::new(),
+            gutters,
         }
     }
 
-    pub fn gutters(&self) -> &[(Gutter, usize)] {
-        GUTTERS
-    }
-
     pub fn inner_area(&self) -> Rect {
         // TODO: cache this
         let offset = self
-            .gutters()
+            .gutters
             .iter()
             .map(|(_, width)| *width as u16)
             .sum::<u16>()
@@ -324,11 +336,16 @@ mod tests {
     use super::*;
     use helix_core::Rope;
     const OFFSET: u16 = 7; // 1 diagnostic + 5 linenr + 1 gutter
-                           // const OFFSET: u16 = GUTTERS.iter().map(|(_, width)| *width as u16).sum();
+    const OFFSET_WITHOUT_LINE_NUMBERS: u16 = 2; // 1 diagnostic + 1 gutter
+                                                // const OFFSET: u16 = GUTTERS.iter().map(|(_, width)| *width as u16).sum();
+    use crate::editor::GutterType;
 
     #[test]
     fn test_text_pos_at_screen_coords() {
-        let mut view = View::new(DocumentId::default());
+        let mut view = View::new(
+            DocumentId::default(),
+            vec![GutterType::Diagnostics, GutterType::LineNumbers],
+        );
         view.area = Rect::new(40, 40, 40, 40);
         let rope = Rope::from_str("abc\n\tdef");
         let text = rope.slice(..);
@@ -373,8 +390,35 @@ mod tests {
     }
 
     #[test]
+    fn test_text_pos_at_screen_coords_without_line_numbers_gutter() {
+        let mut view = View::new(DocumentId::default(), vec![GutterType::Diagnostics]);
+        view.area = Rect::new(40, 40, 40, 40);
+        let rope = Rope::from_str("abc\n\tdef");
+        let text = rope.slice(..);
+        assert_eq!(
+            view.text_pos_at_screen_coords(&text, 41, 40 + OFFSET_WITHOUT_LINE_NUMBERS + 1, 4),
+            Some(4)
+        );
+    }
+
+    #[test]
+    fn test_text_pos_at_screen_coords_without_any_gutters() {
+        let mut view = View::new(DocumentId::default(), vec![]);
+        view.area = Rect::new(40, 40, 40, 40);
+        let rope = Rope::from_str("abc\n\tdef");
+        let text = rope.slice(..);
+        assert_eq!(
+            view.text_pos_at_screen_coords(&text, 41, 40 + 1, 4),
+            Some(4)
+        );
+    }
+
+    #[test]
     fn test_text_pos_at_screen_coords_cjk() {
-        let mut view = View::new(DocumentId::default());
+        let mut view = View::new(
+            DocumentId::default(),
+            vec![GutterType::Diagnostics, GutterType::LineNumbers],
+        );
         view.area = Rect::new(40, 40, 40, 40);
         let rope = Rope::from_str("Hi! こんにちは皆さん");
         let text = rope.slice(..);
@@ -411,7 +455,10 @@ mod tests {
 
     #[test]
     fn test_text_pos_at_screen_coords_graphemes() {
-        let mut view = View::new(DocumentId::default());
+        let mut view = View::new(
+            DocumentId::default(),
+            vec![GutterType::Diagnostics, GutterType::LineNumbers],
+        );
         view.area = Rect::new(40, 40, 40, 40);
         let rope = Rope::from_str("Hèl̀l̀ò world!");
         let text = rope.slice(..);