Strip carriage returns from all text in text::Buffer

* Moving the logic from Rope to text::Buffer makes it easier
  to keep the Rope in sync with the fragment tree.
* Removing carriage return characters is lossier, but is much
  simpler than incrementally maintaining the invariant that
  there are no carriage returns followed by newlines. We may
  want to do something smarter in the future.

Co-authored-by: Keith Simmons <keith@zed.dev>

crates/language/src/buffer.rs

@@ -53,7 +53,6 @@ pub struct Buffer {
     saved_version: clock::Global,
     saved_version_fingerprint: String,
     saved_mtime: SystemTime,
-    line_ending: LineEnding,
     transaction_depth: usize,
     was_dirty_before_starting_transaction: Option<bool>,
     language: Option<Arc<Language>>,
@@ -98,12 +97,6 @@ pub enum IndentKind {
     Tab,
 }
 
-#[derive(Copy, Debug, Clone, PartialEq, Eq)]
-pub enum LineEnding {
-    Unix,
-    Windows,
-}
-
 #[derive(Clone, Debug)]
 struct SelectionSet {
     line_mode: bool,
@@ -319,12 +312,9 @@ impl Buffer {
         base_text: T,
         cx: &mut ModelContext<Self>,
     ) -> Self {
-        let base_text = base_text.into();
-        let line_ending = LineEnding::detect(&base_text);
         Self::build(
-            TextBuffer::new(replica_id, cx.model_id() as u64, base_text),
+            TextBuffer::new(replica_id, cx.model_id() as u64, base_text.into()),
             None,
-            line_ending,
         )
     }
 
@@ -334,12 +324,9 @@ impl Buffer {
         file: Arc<dyn File>,
         cx: &mut ModelContext<Self>,
     ) -> Self {
-        let base_text = base_text.into();
-        let line_ending = LineEnding::detect(&base_text);
         Self::build(
-            TextBuffer::new(replica_id, cx.model_id() as u64, base_text),
+            TextBuffer::new(replica_id, cx.model_id() as u64, base_text.into()),
             Some(file),
-            line_ending,
         )
     }
 
@@ -350,9 +337,11 @@ impl Buffer {
         cx: &mut ModelContext<Self>,
     ) -> Result<Self> {
         let buffer = TextBuffer::new(replica_id, message.id, message.base_text);
-        let line_ending = proto::LineEnding::from_i32(message.line_ending)
-            .ok_or_else(|| anyhow!("missing line_ending"))?;
-        let mut this = Self::build(buffer, file, LineEnding::from_proto(line_ending));
+        let mut this = Self::build(buffer, file);
+        this.text.set_line_ending(proto::deserialize_line_ending(
+            proto::LineEnding::from_i32(message.line_ending)
+                .ok_or_else(|| anyhow!("missing line_ending"))?,
+        ));
         let ops = message
             .operations
             .into_iter()
@@ -417,7 +406,7 @@ impl Buffer {
             diagnostics: proto::serialize_diagnostics(self.diagnostics.iter()),
             diagnostics_timestamp: self.diagnostics_timestamp.value,
             completion_triggers: self.completion_triggers.clone(),
-            line_ending: self.line_ending.to_proto() as i32,
+            line_ending: proto::serialize_line_ending(self.line_ending()) as i32,
         }
     }
 
@@ -426,7 +415,7 @@ impl Buffer {
         self
     }
 
-    fn build(buffer: TextBuffer, file: Option<Arc<dyn File>>, line_ending: LineEnding) -> Self {
+    fn build(buffer: TextBuffer, file: Option<Arc<dyn File>>) -> Self {
         let saved_mtime;
         if let Some(file) = file.as_ref() {
             saved_mtime = file.mtime();
@@ -442,7 +431,6 @@ impl Buffer {
             was_dirty_before_starting_transaction: None,
             text: buffer,
             file,
-            line_ending,
             syntax_tree: Mutex::new(None),
             parsing_in_background: false,
             parse_count: 0,
@@ -503,7 +491,7 @@ impl Buffer {
             self.remote_id(),
             text,
             version,
-            self.line_ending,
+            self.line_ending(),
             cx.as_mut(),
         );
         cx.spawn(|this, mut cx| async move {
@@ -559,7 +547,7 @@ impl Buffer {
                         this.did_reload(
                             this.version(),
                             this.as_rope().fingerprint(),
-                            this.line_ending,
+                            this.line_ending(),
                             new_mtime,
                             cx,
                         );
@@ -584,14 +572,14 @@ impl Buffer {
     ) {
         self.saved_version = version;
         self.saved_version_fingerprint = fingerprint;
-        self.line_ending = line_ending;
+        self.text.set_line_ending(line_ending);
         self.saved_mtime = mtime;
         if let Some(file) = self.file.as_ref().and_then(|f| f.as_local()) {
             file.buffer_reloaded(
                 self.remote_id(),
                 &self.saved_version,
                 self.saved_version_fingerprint.clone(),
-                self.line_ending,
+                self.line_ending(),
                 self.saved_mtime,
                 cx,
             );
@@ -970,13 +958,13 @@ impl Buffer {
         }
     }
 
-    pub(crate) fn diff(&self, new_text: String, cx: &AppContext) -> Task<Diff> {
+    pub(crate) fn diff(&self, mut new_text: String, cx: &AppContext) -> Task<Diff> {
         let old_text = self.as_rope().clone();
         let base_version = self.version();
         cx.background().spawn(async move {
             let old_text = old_text.to_string();
             let line_ending = LineEnding::detect(&new_text);
-            let new_text = new_text.replace("\r\n", "\n").replace('\r', "\n");
+            LineEnding::strip_carriage_returns(&mut new_text);
             let changes = TextDiff::from_lines(old_text.as_str(), new_text.as_str())
                 .iter_all_changes()
                 .map(|c| (c.tag(), c.value().len()))
@@ -999,7 +987,7 @@ impl Buffer {
         if self.version == diff.base_version {
             self.finalize_last_transaction();
             self.start_transaction();
-            self.line_ending = diff.line_ending;
+            self.text.set_line_ending(diff.line_ending);
             let mut offset = diff.start_offset;
             for (tag, len) in diff.changes {
                 let range = offset..(offset + len);
@@ -1514,10 +1502,6 @@ impl Buffer {
     pub fn completion_triggers(&self) -> &[String] {
         &self.completion_triggers
     }
-
-    pub fn line_ending(&self) -> LineEnding {
-        self.line_ending
-    }
 }
 
 #[cfg(any(test, feature = "test-support"))]
@@ -2538,52 +2522,6 @@ impl std::ops::SubAssign for IndentSize {
     }
 }
 
-impl LineEnding {
-    pub fn from_proto(style: proto::LineEnding) -> Self {
-        match style {
-            proto::LineEnding::Unix => Self::Unix,
-            proto::LineEnding::Windows => Self::Windows,
-        }
-    }
-
-    fn detect(text: &str) -> Self {
-        let text = &text[..cmp::min(text.len(), 1000)];
-        if let Some(ix) = text.find('\n') {
-            if ix == 0 || text.as_bytes()[ix - 1] != b'\r' {
-                Self::Unix
-            } else {
-                Self::Windows
-            }
-        } else {
-            Default::default()
-        }
-    }
-
-    pub fn as_str(self) -> &'static str {
-        match self {
-            LineEnding::Unix => "\n",
-            LineEnding::Windows => "\r\n",
-        }
-    }
-
-    pub fn to_proto(self) -> proto::LineEnding {
-        match self {
-            LineEnding::Unix => proto::LineEnding::Unix,
-            LineEnding::Windows => proto::LineEnding::Windows,
-        }
-    }
-}
-
-impl Default for LineEnding {
-    fn default() -> Self {
-        #[cfg(unix)]
-        return Self::Unix;
-
-        #[cfg(not(unix))]
-        return Self::Windows;
-    }
-}
-
 impl Completion {
     pub fn sort_key(&self) -> (usize, &str) {
         let kind_key = match self.lsp_completion.kind {

crates/language/src/proto.rs

@@ -11,6 +11,20 @@ use text::*;
 
 pub use proto::{Buffer, BufferState, LineEnding, SelectionSet};
 
+pub fn deserialize_line_ending(message: proto::LineEnding) -> text::LineEnding {
+    match message {
+        LineEnding::Unix => text::LineEnding::Unix,
+        LineEnding::Windows => text::LineEnding::Windows,
+    }
+}
+
+pub fn serialize_line_ending(message: text::LineEnding) -> proto::LineEnding {
+    match message {
+        text::LineEnding::Unix => proto::LineEnding::Unix,
+        text::LineEnding::Windows => proto::LineEnding::Windows,
+    }
+}
+
 pub fn serialize_operation(operation: &Operation) -> proto::Operation {
     proto::Operation {
         variant: Some(match operation {

crates/language/src/tests.rs

@@ -421,7 +421,7 @@ async fn test_outline(cx: &mut gpui::TestAppContext) {
     async fn search<'a>(
         outline: &'a Outline<Anchor>,
         query: &str,
-        cx: &gpui::TestAppContext,
+        cx: &'a gpui::TestAppContext,
     ) -> Vec<(&'a str, Vec<usize>)> {
         let matches = cx
             .read(|cx| outline.search(query, cx.background().clone()))

crates/project/src/project.rs

@@ -20,12 +20,14 @@ use gpui::{
 };
 use language::{
     point_to_lsp,
-    proto::{deserialize_anchor, deserialize_version, serialize_anchor, serialize_version},
+    proto::{
+        deserialize_anchor, deserialize_line_ending, deserialize_version, serialize_anchor,
+        serialize_version,
+    },
     range_from_lsp, range_to_lsp, Anchor, Bias, Buffer, CharKind, CodeAction, CodeLabel,
     Completion, Diagnostic, DiagnosticEntry, DiagnosticSet, Event as BufferEvent, File as _,
-    Language, LanguageRegistry, LanguageServerName, LineEnding, LocalFile, LspAdapter,
-    OffsetRangeExt, Operation, Patch, PointUtf16, TextBufferSnapshot, ToOffset, ToPointUtf16,
-    Transaction,
+    Language, LanguageRegistry, LanguageServerName, LocalFile, LspAdapter, OffsetRangeExt,
+    Operation, Patch, PointUtf16, TextBufferSnapshot, ToOffset, ToPointUtf16, Transaction,
 };
 use lsp::{
     DiagnosticSeverity, DiagnosticTag, DocumentHighlightKind, LanguageServer, LanguageString,
@@ -5542,7 +5544,7 @@ impl Project {
     ) -> Result<()> {
         let payload = envelope.payload;
         let version = deserialize_version(payload.version);
-        let line_ending = LineEnding::from_proto(
+        let line_ending = deserialize_line_ending(
             proto::LineEnding::from_i32(payload.line_ending)
                 .ok_or_else(|| anyhow!("missing line ending"))?,
         );

crates/project/src/worktree.rs

@@ -23,7 +23,7 @@ use gpui::{
     Task,
 };
 use language::{
-    proto::{deserialize_version, serialize_version},
+    proto::{deserialize_version, serialize_line_ending, serialize_version},
     Buffer, DiagnosticEntry, LineEnding, PointUtf16, Rope,
 };
 use lazy_static::lazy_static;
@@ -1750,7 +1750,7 @@ impl language::LocalFile for File {
                     version: serialize_version(&version),
                     mtime: Some(mtime.into()),
                     fingerprint,
-                    line_ending: line_ending.to_proto() as i32,
+                    line_ending: serialize_line_ending(line_ending) as i32,
                 })
                 .log_err();
         }

crates/text/src/random_char_iter.rs

@@ -22,7 +22,7 @@ impl<T: Rng> Iterator for RandomCharIter<T> {
 
         match self.0.gen_range(0..100) {
             // whitespace
-            0..=19 => [' ', '\n', '\t'].choose(&mut self.0).copied(),
+            0..=19 => [' ', '\n', '\r', '\t'].choose(&mut self.0).copied(),
             // two-byte greek letters
             20..=32 => char::from_u32(self.0.gen_range(('α' as u32)..('ω' as u32 + 1))),
             // // three-byte characters

crates/text/src/rope.rs

@@ -58,19 +58,12 @@ impl Rope {
     pub fn push(&mut self, text: &str) {
         let mut new_chunks = SmallVec::<[_; 16]>::new();
         let mut new_chunk = ArrayString::new();
-        let mut chars = text.chars().peekable();
-        while let Some(mut ch) = chars.next() {
+        for ch in text.chars() {
             if new_chunk.len() + ch.len_utf8() > 2 * CHUNK_BASE {
                 new_chunks.push(Chunk(new_chunk));
                 new_chunk = ArrayString::new();
             }
 
-            if ch == '\r' {
-                ch = '\n';
-                if chars.peek().copied() == Some('\n') {
-                    chars.next();
-                }
-            }
             new_chunk.push(ch);
         }
         if !new_chunk.is_empty() {

crates/text/src/tests.rs

@@ -43,6 +43,8 @@ fn test_random_edits(mut rng: StdRng) {
         .take(reference_string_len)
         .collect::<String>();
     let mut buffer = Buffer::new(0, 0, reference_string.clone().into());
+    reference_string = reference_string.replace("\r", "");
+
     buffer.history.group_interval = Duration::from_millis(rng.gen_range(0..=200));
     let mut buffer_versions = Vec::new();
     log::info!(
@@ -56,6 +58,8 @@ fn test_random_edits(mut rng: StdRng) {
         for (old_range, new_text) in edits.iter().rev() {
             reference_string.replace_range(old_range.clone(), &new_text);
         }
+        reference_string = reference_string.replace("\r", "");
+
         assert_eq!(buffer.text(), reference_string);
         log::info!(
             "buffer text {:?}, version: {:?}",
@@ -148,6 +152,20 @@ fn test_random_edits(mut rng: StdRng) {
     }
 }
 
+#[test]
+fn test_line_endings() {
+    let mut buffer = Buffer::new(0, 0, "one\r\ntwo".into());
+    assert_eq!(buffer.text(), "one\ntwo");
+    assert_eq!(buffer.line_ending(), LineEnding::Windows);
+    buffer.check_invariants();
+
+    buffer.edit([(buffer.len()..buffer.len(), "\r\nthree")]);
+    buffer.edit([(0..0, "zero\r\n")]);
+    assert_eq!(buffer.text(), "zero\none\ntwo\nthree");
+    assert_eq!(buffer.line_ending(), LineEnding::Windows);
+    buffer.check_invariants();
+}
+
 #[test]
 fn test_line_len() {
     let mut buffer = Buffer::new(0, 0, "".into());

crates/text/src/text.rs

@@ -63,6 +63,7 @@ pub struct BufferSnapshot {
     remote_id: u64,
     visible_text: Rope,
     deleted_text: Rope,
+    line_ending: LineEnding,
     undo_map: UndoMap,
     fragments: SumTree<Fragment>,
     insertions: SumTree<InsertionFragment>,
@@ -86,6 +87,12 @@ pub struct Transaction {
     pub ranges: Vec<Range<FullOffset>>,
 }
 
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum LineEnding {
+    Unix,
+    Windows,
+}
+
 impl HistoryEntry {
     pub fn transaction_id(&self) -> TransactionId {
         self.transaction.id
@@ -539,7 +546,10 @@ pub struct UndoOperation {
 }
 
 impl Buffer {
-    pub fn new(replica_id: u16, remote_id: u64, base_text: String) -> Buffer {
+    pub fn new(replica_id: u16, remote_id: u64, mut base_text: String) -> Buffer {
+        let line_ending = LineEnding::detect(&base_text);
+        LineEnding::strip_carriage_returns(&mut base_text);
+
         let history = History::new(base_text.into());
         let mut fragments = SumTree::new();
         let mut insertions = SumTree::new();
@@ -547,6 +557,7 @@ impl Buffer {
         let mut local_clock = clock::Local::new(replica_id);
         let mut lamport_clock = clock::Lamport::new(replica_id);
         let mut version = clock::Global::new();
+
         let visible_text = Rope::from(history.base_text.as_ref());
         if visible_text.len() > 0 {
             let insertion_timestamp = InsertionTimestamp {
@@ -577,6 +588,7 @@ impl Buffer {
                 remote_id,
                 visible_text,
                 deleted_text: Rope::new(),
+                line_ending,
                 fragments,
                 insertions,
                 version,
@@ -659,7 +671,7 @@ impl Buffer {
         let mut new_insertions = Vec::new();
         let mut insertion_offset = 0;
 
-        let mut ranges = edits
+        let mut edits = edits
             .map(|(range, new_text)| (range.to_offset(&*self), new_text))
             .peekable();
 
@@ -667,12 +679,12 @@ impl Buffer {
             RopeBuilder::new(self.visible_text.cursor(0), self.deleted_text.cursor(0));
         let mut old_fragments = self.fragments.cursor::<FragmentTextSummary>();
         let mut new_fragments =
-            old_fragments.slice(&ranges.peek().unwrap().0.start, Bias::Right, &None);
+            old_fragments.slice(&edits.peek().unwrap().0.start, Bias::Right, &None);
         new_ropes.push_tree(new_fragments.summary().text);
 
         let mut fragment_start = old_fragments.start().visible;
-        for (range, new_text) in ranges {
-            let new_text = new_text.into();
+        for (range, new_text) in edits {
+            let new_text = LineEnding::strip_carriage_returns_from_arc(new_text.into());
             let fragment_end = old_fragments.end(&None).visible;
 
             // If the current fragment ends before this range, then jump ahead to the first fragment
@@ -715,6 +727,7 @@ impl Buffer {
             // Insert the new text before any existing fragments within the range.
             if !new_text.is_empty() {
                 let new_start = new_fragments.summary().text.visible;
+
                 edits_patch.push(Edit {
                     old: fragment_start..fragment_start,
                     new: new_start..new_start + new_text.len(),
@@ -806,6 +819,10 @@ impl Buffer {
         edit_op
     }
 
+    pub fn set_line_ending(&mut self, line_ending: LineEnding) {
+        self.snapshot.line_ending = line_ending;
+    }
+
     pub fn apply_ops<I: IntoIterator<Item = Operation>>(&mut self, ops: I) -> Result<()> {
         let mut deferred_ops = Vec::new();
         for op in ops {
@@ -1413,6 +1430,8 @@ impl Buffer {
             fragment_summary.text.deleted,
             self.snapshot.deleted_text.len()
         );
+
+        assert!(!self.text().contains("\r\n"));
     }
 
     pub fn set_group_interval(&mut self, group_interval: Duration) {
@@ -1550,6 +1569,10 @@ impl BufferSnapshot {
         self.visible_text.to_string()
     }
 
+    pub fn line_ending(&self) -> LineEnding {
+        self.line_ending
+    }
+
     pub fn deleted_text(&self) -> String {
         self.deleted_text.to_string()
     }
@@ -2311,6 +2334,50 @@ impl operation_queue::Operation for Operation {
     }
 }
 
+impl Default for LineEnding {
+    fn default() -> Self {
+        #[cfg(unix)]
+        return Self::Unix;
+
+        #[cfg(not(unix))]
+        return Self::CRLF;
+    }
+}
+
+impl LineEnding {
+    pub fn as_str(&self) -> &'static str {
+        match self {
+            LineEnding::Unix => "\n",
+            LineEnding::Windows => "\r\n",
+        }
+    }
+
+    pub fn detect(text: &str) -> Self {
+        if let Some(ix) = text[..cmp::min(text.len(), 1000)].find(&['\n']) {
+            let text = text.as_bytes();
+            if ix > 0 && text[ix - 1] == b'\r' {
+                Self::Windows
+            } else {
+                Self::Unix
+            }
+        } else {
+            Self::default()
+        }
+    }
+
+    pub fn strip_carriage_returns(text: &mut String) {
+        text.retain(|c| c != '\r')
+    }
+
+    fn strip_carriage_returns_from_arc(text: Arc<str>) -> Arc<str> {
+        if text.contains('\r') {
+            text.replace('\r', "").into()
+        } else {
+            text
+        }
+    }
+}
+
 pub trait ToOffset {
     fn to_offset<'a>(&self, snapshot: &BufferSnapshot) -> usize;
 }