From a9a718c3cad3af7b9fa38cd1aaa6ceb6c7126130 Mon Sep 17 00:00:00 2001
From: Jan Hrastnik <jan.hrastnik2@gmail.com>
Date: Sun, 13 Jun 2021 21:38:31 +0200
Subject: [PATCH] added some tests and a line_ending helper function in
 document.rs

---
 helix-core/src/lib.rs         |  2 +-
 helix-core/src/line_ending.rs | 64 ++++++++++++++++++++++++++++++++---
 helix-view/src/document.rs    | 16 ++++++++-
 3 files changed, 76 insertions(+), 6 deletions(-)

diff --git a/helix-core/src/lib.rs b/helix-core/src/lib.rs
index 758e614e..35124069 100644
--- a/helix-core/src/lib.rs
+++ b/helix-core/src/lib.rs
@@ -110,5 +110,5 @@ pub use syntax::Syntax;
 pub use diagnostic::Diagnostic;
 pub use state::State;
 
-pub use line_ending::{auto_detect_line_ending, DEFAULT_LINE_ENDING, LineEnding};
+pub use line_ending::{auto_detect_line_ending, LineEnding, DEFAULT_LINE_ENDING};
 pub use transaction::{Assoc, Change, ChangeSet, Operation, Transaction};
diff --git a/helix-core/src/line_ending.rs b/helix-core/src/line_ending.rs
index bcfecaf6..47420f9e 100644
--- a/helix-core/src/line_ending.rs
+++ b/helix-core/src/line_ending.rs
@@ -1,7 +1,6 @@
 use crate::{Rope, RopeGraphemes, RopeSlice};
 
 /// Represents one of the valid Unicode line endings.
-/// VT, FF and PS are excluded here, as we don't expect them to show up as a default line break
 #[derive(PartialEq, Copy, Clone, Debug)]
 pub enum LineEnding {
     Crlf, // CarriageReturn followed by LineFeed
@@ -9,6 +8,9 @@ pub enum LineEnding {
     CR,   // U+000D -- CarriageReturn
     Nel,  // U+0085 -- NextLine
     LS,   // U+2028 -- Line Separator
+    VT,   // U+000B -- VerticalTab
+    FF,   // U+000C -- FormFeed
+    PS,   // U+2029 -- ParagraphSeparator
 }
 
 pub fn rope_slice_to_line_ending(g: &RopeSlice) -> Option<LineEnding> {
@@ -38,8 +40,8 @@ pub fn auto_detect_line_ending(doc: &Rope) -> Option<LineEnding> {
     // based on https://github.com/cessen/led/blob/27572c8838a1c664ee378a19358604063881cc1d/src/editor/mod.rs#L88-L162
 
     let mut ending = None;
-    for line in doc.lines().take(1) {
-        // check first line only - unsure how sound this is
+    // return first matched line ending. Not all possible line endings are being matched, as they might be special-use only
+    for line in doc.lines().take(100) {
         ending = match line.len_chars() {
             1 => {
                 let g = RopeGraphemes::new(line.slice((line.len_chars() - 1)..))
@@ -54,6 +56,9 @@ pub fn auto_detect_line_ending(doc: &Rope) -> Option<LineEnding> {
                 rope_slice_to_line_ending(&g)
             }
             _ => None,
+        };
+        if ending.is_some() {
+            return ending;
         }
     }
     ending
@@ -62,4 +67,55 @@ pub fn auto_detect_line_ending(doc: &Rope) -> Option<LineEnding> {
 #[cfg(target_os = "windows")]
 pub const DEFAULT_LINE_ENDING: LineEnding = LineEnding::Crlf;
 #[cfg(not(target_os = "windows"))]
-pub const DEFAULT_LINE_ENDING: LineEnding = LineEnding::LF;
\ No newline at end of file
+pub const DEFAULT_LINE_ENDING: LineEnding = LineEnding::LF;
+
+#[cfg(test)]
+mod line_ending_tests {
+    use super::*;
+
+    #[test]
+    fn test_autodetect() {
+        assert_eq!(
+            auto_detect_line_ending(&Rope::from_str("\n")),
+            Some(LineEnding::LF)
+        );
+        assert_eq!(
+            auto_detect_line_ending(&Rope::from_str("\r\n")),
+            Some(LineEnding::Crlf)
+        );
+        assert_eq!(auto_detect_line_ending(&Rope::from_str("hello")), None);
+        assert_eq!(auto_detect_line_ending(&Rope::from_str("")), None);
+        assert_eq!(
+            auto_detect_line_ending(&Rope::from_str("hello\nhelix\r\n")),
+            Some(LineEnding::LF)
+        );
+        assert_eq!(
+            auto_detect_line_ending(&Rope::from_str("a formfeed\u{000C}")),
+            None
+        );
+        assert_eq!(
+            auto_detect_line_ending(&Rope::from_str("\n\u{000A}\n \u{000A}")),
+            Some(LineEnding::LF)
+        );
+        assert_eq!(
+            auto_detect_line_ending(&Rope::from_str(
+                "a formfeed\u{000C} with a\u{000C} linefeed\u{000A}"
+            )),
+            Some(LineEnding::LF)
+        );
+        assert_eq!(auto_detect_line_ending(&Rope::from_str("a formfeed\u{000C} with a\u{000C} carriage return linefeed\u{000D}\u{000A} and a linefeed\u{000A}")), Some(LineEnding::Crlf));
+    }
+
+    #[test]
+    fn test_rope_slice_to_line_ending() {
+        let r = Rope::from_str("\r\n");
+        assert_eq!(
+            rope_slice_to_line_ending(&r.slice(1..2)),
+            Some(LineEnding::LF)
+        );
+        assert_eq!(
+            rope_slice_to_line_ending(&r.slice(0..2)),
+            Some(LineEnding::Crlf)
+        );
+    }
+}
diff --git a/helix-view/src/document.rs b/helix-view/src/document.rs
index 704094a6..bd5f8012 100644
--- a/helix-view/src/document.rs
+++ b/helix-view/src/document.rs
@@ -6,9 +6,9 @@ use std::sync::Arc;
 
 use helix_core::{
     chars::{char_is_linebreak, char_is_whitespace},
-    auto_detect_line_ending, DEFAULT_LINE_ENDING, history::History,
     syntax::{LanguageConfiguration, LOADER},
     ChangeSet, Diagnostic, LineEnding, Rope, Selection, State, Syntax, Transaction,
+    DEFAULT_LINE_ENDING,
 };
 
 use crate::{DocumentId, ViewId};
@@ -740,6 +740,20 @@ impl Document {
     pub fn set_diagnostics(&mut self, diagnostics: Vec<Diagnostic>) {
         self.diagnostics = diagnostics;
     }
+
+    pub fn line_ending(&self) -> &str {
+        match self.line_ending {
+            LineEnding::Crlf => "\u{000D}\u{000A}",
+            LineEnding::LF => "\u{000A}",
+            LineEnding::Nel => "\u{0085}",
+            LineEnding::LS => "\u{2028}",
+            LineEnding::CR => "\u{000D}",
+            _ => panic!(
+                "Unexpected line ending: {:?}, expected Crlf, LF, CR, Nel, or LS.",
+                self.line_ending
+            ),
+        }
+    }
 }
 
 #[cfg(test)]