From 225e8ccf31ac554ae0977b4359c50edb2670594e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bla=C5=BE=20Hrastnik?= <blaz@mxxn.io>
Date: Tue, 23 Nov 2021 12:56:46 +0900
Subject: [PATCH] Extract gutters into helix-view

---
 helix-term/src/ui/editor.rs | 97 +------------------------------------
 helix-view/src/gutter.rs    | 95 ++++++++++++++++++++++++++++++++++++
 helix-view/src/lib.rs       |  1 +
 helix-view/src/view.rs      | 24 +++++++--
 4 files changed, 117 insertions(+), 100 deletions(-)
 create mode 100644 helix-view/src/gutter.rs

diff --git a/helix-term/src/ui/editor.rs b/helix-term/src/ui/editor.rs
index 82fb8fbf6..83be816f9 100644
--- a/helix-term/src/ui/editor.rs
+++ b/helix-term/src/ui/editor.rs
@@ -17,7 +17,6 @@ use helix_core::{
 };
 use helix_view::{
     document::{Mode, SCRATCH_BUFFER_NAME},
-    editor::{Config, LineNumber},
     graphics::{CursorKind, Modifier, Rect, Style},
     info::Info,
     input::KeyEvent,
@@ -421,97 +420,12 @@ impl EditorView {
             .map(|range| range.cursor_line(text))
             .collect();
 
-        use std::fmt::Write;
-
-        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
-            })
-        }
-
-        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$}", '~', width).unwrap();
-                    Some(linenr)
-                } else {
-                    let line = match config {
-                        LineNumber::Absolute => line + 1,
-                        LineNumber::Relative => {
-                            if current_line == line {
-                                line + 1
-                            } else {
-                                abs_diff(current_line, line)
-                            }
-                        }
-                    };
-                    let style = if selected && is_focused {
-                        linenr_select
-                    } else {
-                        linenr
-                    };
-                    write!(out, "{:>1$}", line, width).unwrap();
-                    Some(style)
-                }
-            })
-        }
-
-        type GutterFn<'doc> = Box<dyn Fn(usize, bool, &mut String) -> Option<Style> + 'doc>;
-        type Gutter =
-            for<'doc> fn(&'doc Document, &View, &Theme, &Config, bool, usize) -> GutterFn<'doc>;
-        let gutters: &[(Gutter, usize)] = &[(diagnostic, 1), (line_number, 5)];
-
         let mut offset = 0;
 
         // avoid lots of small allocations by reusing a text buffer for each line
         let mut text = String::with_capacity(8);
 
-        for (constructor, width) in gutters {
+        for (constructor, width) in view.gutters() {
             let gutter = constructor(doc, view, theme, config, 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() {
@@ -1214,12 +1128,3 @@ fn canonicalize_key(key: &mut KeyEvent) {
         key.modifiers.remove(KeyModifiers::SHIFT)
     }
 }
-
-#[inline]
-const fn abs_diff(a: usize, b: usize) -> usize {
-    if a > b {
-        a - b
-    } else {
-        b - a
-    }
-}
diff --git a/helix-view/src/gutter.rs b/helix-view/src/gutter.rs
new file mode 100644
index 000000000..86773c1db
--- /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
+    }
+}
diff --git a/helix-view/src/lib.rs b/helix-view/src/lib.rs
index 4d19ee2e0..a56c914d4 100644
--- a/helix-view/src/lib.rs
+++ b/helix-view/src/lib.rs
@@ -5,6 +5,7 @@ pub mod clipboard;
 pub mod document;
 pub mod editor;
 pub mod graphics;
+pub mod gutter;
 pub mod info;
 pub mod input;
 pub mod keyboard;
diff --git a/helix-view/src/view.rs b/helix-view/src/view.rs
index a77f15629..217a4940f 100644
--- a/helix-view/src/view.rs
+++ b/helix-view/src/view.rs
@@ -1,6 +1,10 @@
 use std::borrow::Cow;
 
-use crate::{graphics::Rect, Document, DocumentId, ViewId};
+use crate::{
+    graphics::Rect,
+    gutter::{self, Gutter},
+    Document, DocumentId, ViewId,
+};
 use helix_core::{
     graphemes::{grapheme_width, RopeGraphemes},
     line_ending::line_end_char_index,
@@ -60,6 +64,8 @@ impl JumpList {
     }
 }
 
+const GUTTERS: &[(Gutter, usize)] = &[(gutter::diagnostic, 1), (gutter::line_number, 5)];
+
 #[derive(Debug)]
 pub struct View {
     pub id: ViewId,
@@ -83,10 +89,19 @@ impl View {
         }
     }
 
+    pub fn gutters(&self) -> &[(Gutter, usize)] {
+        GUTTERS
+    }
+
     pub fn inner_area(&self) -> Rect {
-        // TODO: not ideal
-        const OFFSET: u16 = 7; // 1 diagnostic + 5 linenr + 1 gutter
-        self.area.clip_left(OFFSET).clip_bottom(1) // -1 for statusline
+        // TODO: cache this
+        let offset = self
+            .gutters()
+            .iter()
+            .map(|(_, width)| *width as u16)
+            .sum::<u16>()
+            + 1; // +1 for some space between gutters and line
+        self.area.clip_left(offset).clip_bottom(1) // -1 for statusline
     }
 
     //
@@ -276,6 +291,7 @@ 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();
 
     #[test]
     fn test_text_pos_at_screen_coords() {