WIPWIPWIPWIPW

Co-authored-by: Conrad <conrad@zed.dev>

Cargo.lock

@@ -7702,11 +7702,13 @@ dependencies = [
  "ctor",
  "env_logger 0.11.5",
  "futures 0.3.31",
+ "git",
  "gpui",
  "itertools 0.13.0",
  "language",
  "log",
  "parking_lot",
+ "project",
  "rand 0.8.5",
  "serde",
  "settings",

crates/collab/src/tests/editor_tests.rs

@@ -9,6 +9,7 @@ use editor::{
         ConfirmCodeAction, ConfirmCompletion, ConfirmRename, ContextMenuFirst, Redo, Rename,
         ToggleCodeActions, Undo,
     },
+    display_map::RowInfo,
     test::editor_test_context::{AssertionContextManager, EditorTestContext},
     Editor,
 };
@@ -20,7 +21,6 @@ use language::{
     language_settings::{AllLanguageSettings, InlayHintSettings},
     FakeLspAdapter,
 };
-use multi_buffer::MultiBufferRow;
 use project::{
     project_settings::{InlineBlameSettings, ProjectSettings},
     SERVER_PROGRESS_THROTTLE_TIMEOUT,
@@ -2075,7 +2075,15 @@ async fn test_git_blame_is_forwarded(cx_a: &mut TestAppContext, cx_b: &mut TestA
         let blame = editor_b.blame().expect("editor_b should have blame now");
         let entries = blame.update(cx, |blame, cx| {
             blame
-                .blame_for_rows((0..4).map(MultiBufferRow).map(Some), cx)
+                .blame_for_rows(
+                    &(0..4)
+                        .map(|row| RowInfo {
+                            buffer_row: Some(row),
+                            ..Default::default()
+                        })
+                        .collect::<Vec<_>>(),
+                    cx,
+                )
                 .collect::<Vec<_>>()
         });
 
@@ -2114,7 +2122,15 @@ async fn test_git_blame_is_forwarded(cx_a: &mut TestAppContext, cx_b: &mut TestA
         let blame = editor_b.blame().expect("editor_b should have blame now");
         let entries = blame.update(cx, |blame, cx| {
             blame
-                .blame_for_rows((0..4).map(MultiBufferRow).map(Some), cx)
+                .blame_for_rows(
+                    &(0..4)
+                        .map(|row| RowInfo {
+                            buffer_row: Some(row),
+                            ..Default::default()
+                        })
+                        .collect::<Vec<_>>(),
+                    cx,
+                )
                 .collect::<Vec<_>>()
         });
 
@@ -2141,7 +2157,15 @@ async fn test_git_blame_is_forwarded(cx_a: &mut TestAppContext, cx_b: &mut TestA
         let blame = editor_b.blame().expect("editor_b should have blame now");
         let entries = blame.update(cx, |blame, cx| {
             blame
-                .blame_for_rows((0..4).map(MultiBufferRow).map(Some), cx)
+                .blame_for_rows(
+                    &(0..4)
+                        .map(|row| RowInfo {
+                            buffer_row: Some(row),
+                            ..Default::default()
+                        })
+                        .collect::<Vec<_>>(),
+                    cx,
+                )
                 .collect::<Vec<_>>()
         });
 

crates/editor/src/display_map.rs

@@ -20,6 +20,7 @@
 mod block_map;
 mod crease_map;
 mod custom_highlights;
+mod diff_map;
 mod fold_map;
 mod inlay_map;
 pub(crate) mod invisibles;
@@ -30,16 +31,19 @@ use crate::{
     hover_links::InlayHighlight, movement::TextLayoutDetails, EditorStyle, InlayId, RowExt,
 };
 pub use block_map::{
-    Block, BlockBufferRows, BlockChunks as DisplayChunks, BlockContext, BlockId, BlockMap,
-    BlockPlacement, BlockPoint, BlockProperties, BlockStyle, CustomBlockId, RenderBlock,
+    Block, BlockChunks as DisplayChunks, BlockContext, BlockId, BlockMap, BlockPlacement,
+    BlockPoint, BlockProperties, BlockRows, BlockStyle, CustomBlockId, RenderBlock,
 };
 use block_map::{BlockRow, BlockSnapshot};
 use collections::{HashMap, HashSet};
 pub use crease_map::*;
+use diff_map::{DiffMap, DiffMapSnapshot, DiffOffset, DiffPoint};
 pub use fold_map::{Fold, FoldId, FoldPlaceholder, FoldPoint};
 use fold_map::{FoldMap, FoldSnapshot};
+use git::diff::DiffHunkStatus;
 use gpui::{
-    AnyElement, Font, HighlightStyle, LineLayout, Model, ModelContext, Pixels, UnderlineStyle,
+    AnyElement, AppContext, Font, HighlightStyle, LineLayout, Model, ModelContext, Pixels,
+    UnderlineStyle,
 };
 pub(crate) use inlay_map::Inlay;
 use inlay_map::{InlayMap, InlaySnapshot};
@@ -51,9 +55,10 @@ use language::{
 };
 use lsp::DiagnosticSeverity;
 use multi_buffer::{
-    Anchor, AnchorRangeExt, MultiBuffer, MultiBufferPoint, MultiBufferRow, MultiBufferSnapshot,
-    ToOffset, ToPoint,
+    Anchor, AnchorRangeExt, MultiBuffer, MultiBufferDiffHunk, MultiBufferPoint, MultiBufferRow,
+    MultiBufferSnapshot, RowInfo, ToOffset, ToPoint,
 };
+use project::buffer_store::BufferChangeSet;
 use serde::Deserialize;
 use std::{
     any::TypeId,
@@ -66,7 +71,7 @@ use std::{
 };
 use sum_tree::{Bias, TreeMap};
 use tab_map::{TabMap, TabSnapshot};
-use text::LineIndent;
+use text::{BufferId, LineIndent};
 use ui::{px, SharedString, WindowContext};
 use unicode_segmentation::UnicodeSegmentation;
 use wrap_map::{WrapMap, WrapSnapshot};
@@ -96,6 +101,8 @@ pub struct DisplayMap {
     buffer_subscription: BufferSubscription,
     /// Decides where the [`Inlay`]s should be displayed.
     inlay_map: InlayMap,
+    /// Decides where diff hunks should be.
+    diff_map: Model<DiffMap>,
     /// Decides where the fold indicators should be and tracks parts of a source file that are currently folded.
     fold_map: FoldMap,
     /// Keeps track of hard tabs in a buffer.
@@ -134,7 +141,8 @@ impl DisplayMap {
         let tab_size = Self::tab_size(&buffer, cx);
         let buffer_snapshot = buffer.read(cx).snapshot(cx);
         let crease_map = CreaseMap::new(&buffer_snapshot);
-        let (inlay_map, snapshot) = InlayMap::new(buffer_snapshot);
+        let (diff_map, snapshot) = DiffMap::new(buffer.clone(), cx);
+        let (inlay_map, snapshot) = InlayMap::new(snapshot);
         let (fold_map, snapshot) = FoldMap::new(snapshot);
         let (tab_map, snapshot) = TabMap::new(snapshot, tab_size);
         let (wrap_map, snapshot) = WrapMap::new(snapshot, font, font_size, wrap_width, cx);
@@ -153,6 +161,7 @@ impl DisplayMap {
             buffer_subscription,
             fold_map,
             inlay_map,
+            diff_map,
             tab_map,
             wrap_map,
             block_map,
@@ -168,7 +177,10 @@ impl DisplayMap {
     pub fn snapshot(&mut self, cx: &mut ModelContext<Self>) -> DisplaySnapshot {
         let buffer_snapshot = self.buffer.read(cx).snapshot(cx);
         let edits = self.buffer_subscription.consume().into_inner();
-        let (inlay_snapshot, edits) = self.inlay_map.sync(buffer_snapshot, edits);
+        let (diff_snapshot, edits) = self.diff_map.update(cx, |diff_map, cx| {
+            diff_map.sync(buffer_snapshot.clone(), edits, cx)
+        });
+        let (inlay_snapshot, edits) = self.inlay_map.sync(diff_snapshot, edits);
         let (fold_snapshot, edits) = self.fold_map.read(inlay_snapshot.clone(), edits);
         let tab_size = Self::tab_size(&self.buffer, cx);
         let (tab_snapshot, edits) = self.tab_map.sync(fold_snapshot.clone(), edits, tab_size);
@@ -217,7 +229,10 @@ impl DisplayMap {
         let buffer_snapshot = self.buffer.read(cx).snapshot(cx);
         let edits = self.buffer_subscription.consume().into_inner();
         let tab_size = Self::tab_size(&self.buffer, cx);
-        let (snapshot, edits) = self.inlay_map.sync(buffer_snapshot.clone(), edits);
+        let (snapshot, edits) = self.diff_map.update(cx, |diff_map, cx| {
+            diff_map.sync(buffer_snapshot.clone(), edits, cx)
+        });
+        let (snapshot, edits) = self.inlay_map.sync(snapshot, edits);
         let (mut fold_map, snapshot, edits) = self.fold_map.write(snapshot, edits);
         let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
         let (snapshot, edits) = self
@@ -290,6 +305,9 @@ impl DisplayMap {
         let snapshot = self.buffer.read(cx).snapshot(cx);
         let edits = self.buffer_subscription.consume().into_inner();
         let tab_size = Self::tab_size(&self.buffer, cx);
+        let (snapshot, edits) = self
+            .diff_map
+            .update(cx, |diff_map, cx| diff_map.sync(snapshot, edits, cx));
         let (snapshot, edits) = self.inlay_map.sync(snapshot, edits);
         let (mut fold_map, snapshot, edits) = self.fold_map.write(snapshot, edits);
         let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
@@ -319,6 +337,9 @@ impl DisplayMap {
             .collect::<Vec<_>>();
         let edits = self.buffer_subscription.consume().into_inner();
         let tab_size = Self::tab_size(&self.buffer, cx);
+        let (snapshot, edits) = self
+            .diff_map
+            .update(cx, |diff_map, cx| diff_map.sync(snapshot, edits, cx));
         let (snapshot, edits) = self.inlay_map.sync(snapshot, edits);
         let (mut fold_map, snapshot, edits) = self.fold_map.write(snapshot, edits);
         let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
@@ -341,6 +362,9 @@ impl DisplayMap {
         let snapshot = self.buffer.read(cx).snapshot(cx);
         let edits = self.buffer_subscription.consume().into_inner();
         let tab_size = Self::tab_size(&self.buffer, cx);
+        let (snapshot, edits) = self
+            .diff_map
+            .update(cx, |diff_map, cx| diff_map.sync(snapshot, edits, cx));
         let (snapshot, edits) = self.inlay_map.sync(snapshot, edits);
         let (snapshot, edits) = self.fold_map.read(snapshot, edits);
         let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
@@ -355,6 +379,9 @@ impl DisplayMap {
         let snapshot = self.buffer.read(cx).snapshot(cx);
         let edits = self.buffer_subscription.consume().into_inner();
         let tab_size = Self::tab_size(&self.buffer, cx);
+        let (snapshot, edits) = self
+            .diff_map
+            .update(cx, |diff_map, cx| diff_map.sync(snapshot, edits, cx));
         let (snapshot, edits) = self.inlay_map.sync(snapshot, edits);
         let (snapshot, edits) = self.fold_map.read(snapshot, edits);
         let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
@@ -387,6 +414,71 @@ impl DisplayMap {
         self.crease_map.remove(crease_ids, &snapshot)
     }
 
+    pub fn add_change_set(
+        &mut self,
+        change_set: Model<BufferChangeSet>,
+        cx: &mut ModelContext<Self>,
+    ) {
+        self.diff_map.update(cx, |diff_map, cx| {
+            diff_map.add_change_set(change_set, cx);
+        });
+    }
+
+    pub fn has_multiple_hunks(&self, cx: &AppContext) -> bool {
+        self.diff_map.read(cx).has_multiple_hunks()
+    }
+
+    pub fn has_expanded_diff_hunks_in_ranges(
+        &mut self,
+        ranges: &[Range<multi_buffer::Anchor>],
+        cx: &mut ModelContext<Self>,
+    ) -> bool {
+        self.diff_map
+            .read(cx)
+            .has_expanded_diff_hunks_in_ranges(ranges)
+    }
+
+    pub fn set_all_hunks_expanded(&mut self, cx: &mut ModelContext<Self>) {
+        self.update_diff_map(cx, |diff_map, cx| diff_map.set_all_hunks_expanded(cx))
+    }
+
+    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut ModelContext<Self>) {
+        self.update_diff_map(cx, |diff_map, cx| diff_map.expand_diff_hunks(ranges, cx))
+    }
+
+    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut ModelContext<Self>) {
+        self.update_diff_map(cx, |diff_map, cx| diff_map.collapse_diff_hunks(ranges, cx))
+    }
+
+    pub fn diff_base_for<'a>(
+        &'a self,
+        buffer_id: BufferId,
+        cx: &'a AppContext,
+    ) -> Option<&'a Model<BufferChangeSet>> {
+        self.diff_map.read(cx).diff_base_for(buffer_id)
+    }
+
+    fn update_diff_map(
+        &mut self,
+        cx: &mut ModelContext<Self>,
+        f: impl FnOnce(&mut DiffMap, &mut ModelContext<DiffMap>),
+    ) {
+        let snapshot = self.buffer.read(cx).snapshot(cx);
+        let edits = self.buffer_subscription.consume().into_inner();
+        let (snapshot, edits) = self.diff_map.update(cx, |diff_map, cx| {
+            f(diff_map, cx);
+            diff_map.sync(snapshot, edits, cx)
+        });
+        let (snapshot, edits) = self.inlay_map.sync(snapshot, edits);
+        let (snapshot, edits) = self.fold_map.read(snapshot, edits);
+        let tab_size = Self::tab_size(&self.buffer, cx);
+        let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
+        let (snapshot, edits) = self
+            .wrap_map
+            .update(cx, |map, cx| map.sync(snapshot, edits, cx));
+        self.block_map.write(snapshot, edits);
+    }
+
     pub fn insert_blocks(
         &mut self,
         blocks: impl IntoIterator<Item = BlockProperties<Anchor>>,
@@ -395,6 +487,9 @@ impl DisplayMap {
         let snapshot = self.buffer.read(cx).snapshot(cx);
         let edits = self.buffer_subscription.consume().into_inner();
         let tab_size = Self::tab_size(&self.buffer, cx);
+        let (snapshot, edits) = self
+            .diff_map
+            .update(cx, |diff_map, cx| diff_map.sync(snapshot, edits, cx));
         let (snapshot, edits) = self.inlay_map.sync(snapshot, edits);
         let (snapshot, edits) = self.fold_map.read(snapshot, edits);
         let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
@@ -413,6 +508,9 @@ impl DisplayMap {
         let snapshot = self.buffer.read(cx).snapshot(cx);
         let edits = self.buffer_subscription.consume().into_inner();
         let tab_size = Self::tab_size(&self.buffer, cx);
+        let (snapshot, edits) = self
+            .diff_map
+            .update(cx, |diff_map, cx| diff_map.sync(snapshot, edits, cx));
         let (snapshot, edits) = self.inlay_map.sync(snapshot, edits);
         let (snapshot, edits) = self.fold_map.read(snapshot, edits);
         let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
@@ -431,6 +529,9 @@ impl DisplayMap {
         let snapshot = self.buffer.read(cx).snapshot(cx);
         let edits = self.buffer_subscription.consume().into_inner();
         let tab_size = Self::tab_size(&self.buffer, cx);
+        let (snapshot, edits) = self
+            .diff_map
+            .update(cx, |diff_map, cx| diff_map.sync(snapshot, edits, cx));
         let (snapshot, edits) = self.inlay_map.sync(snapshot, edits);
         let (snapshot, edits) = self.fold_map.read(snapshot, edits);
         let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
@@ -449,6 +550,9 @@ impl DisplayMap {
         let snapshot = self.buffer.read(cx).snapshot(cx);
         let edits = self.buffer_subscription.consume().into_inner();
         let tab_size = Self::tab_size(&self.buffer, cx);
+        let (snapshot, edits) = self
+            .diff_map
+            .update(cx, |diff_map, cx| diff_map.sync(snapshot, edits, cx));
         let (snapshot, edits) = self.inlay_map.sync(snapshot, edits);
         let (snapshot, edits) = self.fold_map.read(snapshot, edits);
         let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
@@ -524,7 +628,10 @@ impl DisplayMap {
         }
         let buffer_snapshot = self.buffer.read(cx).snapshot(cx);
         let edits = self.buffer_subscription.consume().into_inner();
-        let (snapshot, edits) = self.inlay_map.sync(buffer_snapshot, edits);
+        let (snapshot, edits) = self.diff_map.update(cx, |diff_map, cx| {
+            diff_map.sync(buffer_snapshot.clone(), edits, cx)
+        });
+        let (snapshot, edits) = self.inlay_map.sync(snapshot.clone(), edits);
         let (snapshot, edits) = self.fold_map.read(snapshot, edits);
         let tab_size = Self::tab_size(&self.buffer, cx);
         let (snapshot, edits) = self.tab_map.sync(snapshot, edits, tab_size);
@@ -710,17 +817,35 @@ impl DisplaySnapshot {
         self.fold_snapshot.fold_count()
     }
 
+    pub fn diff_hunks<'a>(&'a self) -> impl Iterator<Item = MultiBufferDiffHunk> + 'a {
+        self.diff_snapshot()
+            .diff_hunks_in_range(0..self.buffer_snapshot.len())
+    }
+
+    pub fn diff_hunks_in_range<'a, T: ToOffset>(
+        &'a self,
+        range: Range<T>,
+    ) -> impl Iterator<Item = MultiBufferDiffHunk> + 'a {
+        self.diff_snapshot().diff_hunks_in_range(range)
+    }
+
+    pub fn diff_hunks_in_range_rev<'a, T: ToOffset>(
+        &'a self,
+        range: Range<T>,
+    ) -> impl Iterator<Item = MultiBufferDiffHunk> + 'a {
+        self.diff_snapshot().diff_hunks_in_range_rev(range)
+    }
+
+    pub fn has_diff_hunks(&self) -> bool {
+        self.diff_snapshot().has_diff_hunks()
+    }
+
     pub fn is_empty(&self) -> bool {
         self.buffer_snapshot.len() == 0
     }
 
-    pub fn buffer_rows(
-        &self,
-        start_row: DisplayRow,
-    ) -> impl Iterator<Item = Option<MultiBufferRow>> + '_ {
-        self.block_snapshot
-            .buffer_rows(BlockRow(start_row.0))
-            .map(|row| row.map(MultiBufferRow))
+    pub fn row_infos(&self, start_row: DisplayRow) -> impl Iterator<Item = RowInfo> + '_ {
+        self.block_snapshot.row_infos(BlockRow(start_row.0))
     }
 
     pub fn widest_line_number(&self) -> u32 {
@@ -729,7 +854,7 @@ impl DisplaySnapshot {
 
     pub fn prev_line_boundary(&self, mut point: MultiBufferPoint) -> (Point, DisplayPoint) {
         loop {
-            let mut inlay_point = self.inlay_snapshot.to_inlay_point(point);
+            let mut inlay_point = self.inlay_snapshot.make_inlay_point(point);
             let mut fold_point = self.fold_snapshot.to_fold_point(inlay_point, Bias::Left);
             fold_point.0.column = 0;
             inlay_point = fold_point.to_inlay_point(&self.fold_snapshot);
@@ -751,7 +876,7 @@ impl DisplaySnapshot {
     ) -> (MultiBufferPoint, DisplayPoint) {
         let original_point = point;
         loop {
-            let mut inlay_point = self.inlay_snapshot.to_inlay_point(point);
+            let mut inlay_point = self.inlay_snapshot.make_inlay_point(point);
             let mut fold_point = self.fold_snapshot.to_fold_point(inlay_point, Bias::Right);
             fold_point.0.column = self.fold_snapshot.line_len(fold_point.row());
             inlay_point = fold_point.to_inlay_point(&self.fold_snapshot);
@@ -795,7 +920,7 @@ impl DisplaySnapshot {
     }
 
     pub fn point_to_display_point(&self, point: MultiBufferPoint, bias: Bias) -> DisplayPoint {
-        let inlay_point = self.inlay_snapshot.to_inlay_point(point);
+        let inlay_point = self.inlay_snapshot.make_inlay_point(point);
         let fold_point = self.fold_snapshot.to_fold_point(inlay_point, bias);
         let tab_point = self.tab_snapshot.to_tab_point(fold_point);
         let wrap_point = self.wrap_snapshot.tab_point_to_wrap_point(tab_point);
@@ -813,9 +938,15 @@ impl DisplaySnapshot {
             .to_offset(self.display_point_to_inlay_point(point, bias))
     }
 
+    pub fn display_point_to_diff_offset(&self, point: DisplayPoint, bias: Bias) -> DiffOffset {
+        self.diff_snapshot()
+            .point_to_offset(self.display_point_to_diff_point(point, bias))
+    }
+
     pub fn anchor_to_inlay_offset(&self, anchor: Anchor) -> InlayOffset {
-        self.inlay_snapshot
-            .to_inlay_offset(anchor.to_offset(&self.buffer_snapshot))
+        let multibuffer_offset = anchor.to_offset(&self.buffer_snapshot);
+        let diff_offset = self.diff_snapshot().to_diff_offset(multibuffer_offset);
+        self.inlay_snapshot.to_inlay_offset(diff_offset)
     }
 
     pub fn display_point_to_anchor(&self, point: DisplayPoint, bias: Bias) -> Anchor {
@@ -831,6 +962,17 @@ impl DisplaySnapshot {
         fold_point.to_inlay_point(&self.fold_snapshot)
     }
 
+    fn diff_point_to_display_point(&self, diff_point: DiffPoint, bias: Bias) -> DisplayPoint {
+        let inlay_point = self.inlay_snapshot.to_inlay_point(diff_point);
+        let fold_point = self.fold_snapshot.to_fold_point(inlay_point, bias);
+        self.fold_point_to_display_point(fold_point)
+    }
+
+    fn display_point_to_diff_point(&self, point: DisplayPoint, bias: Bias) -> DiffPoint {
+        self.inlay_snapshot
+            .to_diff_point(self.display_point_to_inlay_point(point, bias))
+    }
+
     pub fn display_point_to_fold_point(&self, point: DisplayPoint, bias: Bias) -> FoldPoint {
         let block_point = point.0;
         let wrap_point = self.block_snapshot.to_wrap_point(block_point, bias);
@@ -1068,6 +1210,22 @@ impl DisplaySnapshot {
             })
     }
 
+    pub fn anchor_before(&self, point: DisplayPoint) -> DisplayAnchor {
+        let diff_point = self.display_point_to_diff_point(point, Bias::Left);
+        self.diff_snapshot().point_to_anchor(diff_point, Bias::Left)
+    }
+
+    pub fn anchor_after(&self, point: DisplayPoint) -> DisplayAnchor {
+        let diff_point = self.display_point_to_diff_point(point, Bias::Left);
+        self.diff_snapshot()
+            .point_to_anchor(diff_point, Bias::Right)
+    }
+
+    pub fn anchor_to_point(&self, anchor: DisplayAnchor) -> DisplayPoint {
+        let diff_point = self.diff_snapshot().anchor_to_point(anchor);
+        self.diff_point_to_display_point(diff_point, Bias::Left)
+    }
+
     pub fn clip_point(&self, point: DisplayPoint, bias: Bias) -> DisplayPoint {
         let mut clipped = self.block_snapshot.clip_point(point.0, bias);
         if self.clip_at_line_ends {
@@ -1307,6 +1465,51 @@ impl DisplaySnapshot {
     pub fn excerpt_header_height(&self) -> u32 {
         self.block_snapshot.excerpt_header_height
     }
+
+    pub(crate) fn diff_snapshot(&self) -> &DiffMapSnapshot {
+        &self.inlay_snapshot.diff_map_snapshot
+    }
+}
+
+#[derive(Clone, Copy, Eq, PartialEq, Debug, Hash)]
+pub struct DisplayAnchor {
+    pub anchor: multi_buffer::Anchor,
+    pub diff_base_anchor: Option<text::Anchor>,
+}
+
+impl DisplayAnchor {
+    pub fn min() -> Self {
+        Self {
+            anchor: multi_buffer::Anchor::min(),
+            diff_base_anchor: None,
+        }
+    }
+
+    pub fn max() -> Self {
+        Self {
+            anchor: multi_buffer::Anchor::max(),
+            diff_base_anchor: None,
+        }
+    }
+
+    pub fn cmp(&self, other: &DisplayAnchor, map: &DisplaySnapshot) -> std::cmp::Ordering {
+        map.diff_snapshot().compare_anchors(self, other)
+    }
+}
+
+pub trait DisplayCoordinate {
+    fn to_display_anchor(self, map: &DisplaySnapshot) -> DisplayAnchor;
+}
+
+impl DisplayCoordinate for DisplayAnchor {
+    fn to_display_anchor(self, _: &DisplaySnapshot) -> DisplayAnchor {
+        self
+    }
+}
+impl DisplayCoordinate for DisplayPoint {
+    fn to_display_anchor(self, map: &DisplaySnapshot) -> DisplayAnchor {
+        map.anchor_before(self)
+    }
 }
 
 #[derive(Copy, Clone, Default, Eq, Ord, PartialOrd, PartialEq)]

crates/editor/src/display_map/block_map.rs

@@ -2,7 +2,7 @@ use super::{
     wrap_map::{self, WrapEdit, WrapPoint, WrapSnapshot},
     Highlights,
 };
-use crate::{EditorStyle, GutterDimensions};
+use crate::{EditorStyle, GutterDimensions, RowInfo};
 use collections::{Bound, HashMap, HashSet};
 use gpui::{AnyElement, AppContext, EntityId, Pixels, WindowContext};
 use language::{Chunk, Patch, Point};
@@ -399,9 +399,9 @@ pub struct BlockChunks<'a> {
 }
 
 #[derive(Clone)]
-pub struct BlockBufferRows<'a> {
+pub struct BlockRows<'a> {
     transforms: sum_tree::Cursor<'a, Transform, (BlockRow, WrapRow)>,
-    input_buffer_rows: wrap_map::WrapBufferRows<'a>,
+    input_rows: wrap_map::WrapRows<'a>,
     output_row: BlockRow,
     started: bool,
 }
@@ -1360,7 +1360,7 @@ impl BlockSnapshot {
         }
     }
 
-    pub(super) fn buffer_rows(&self, start_row: BlockRow) -> BlockBufferRows {
+    pub(super) fn row_infos(&self, start_row: BlockRow) -> BlockRows {
         let mut cursor = self.transforms.cursor::<(BlockRow, WrapRow)>(&());
         cursor.seek(&start_row, Bias::Right, &());
         let (output_start, input_start) = cursor.start();
@@ -1373,9 +1373,9 @@ impl BlockSnapshot {
             0
         };
         let input_start_row = input_start.0 + overshoot;
-        BlockBufferRows {
+        BlockRows {
             transforms: cursor,
-            input_buffer_rows: self.wrap_snapshot.buffer_rows(input_start_row),
+            input_rows: self.wrap_snapshot.row_infos(input_start_row),
             output_row: start_row,
             started: false,
         }
@@ -1766,8 +1766,8 @@ impl<'a> Iterator for BlockChunks<'a> {
     }
 }
 
-impl<'a> Iterator for BlockBufferRows<'a> {
-    type Item = Option<u32>;
+impl<'a> Iterator for BlockRows<'a> {
+    type Item = RowInfo;
 
     fn next(&mut self) -> Option<Self::Item> {
         if self.started {
@@ -1796,7 +1796,7 @@ impl<'a> Iterator for BlockBufferRows<'a> {
                 .as_ref()
                 .map_or(true, |block| block.is_replacement())
             {
-                self.input_buffer_rows.seek(self.transforms.start().1 .0);
+                self.input_rows.seek(self.transforms.start().1 .0);
             }
         }
 
@@ -1804,15 +1804,15 @@ impl<'a> Iterator for BlockBufferRows<'a> {
         if let Some(block) = transform.block.as_ref() {
             if block.is_replacement() && self.transforms.start().0 == self.output_row {
                 if matches!(block, Block::FoldedBuffer { .. }) {
-                    Some(None)
+                    Some(RowInfo::default())
                 } else {
-                    Some(self.input_buffer_rows.next().unwrap())
+                    Some(self.input_rows.next().unwrap())
                 }
             } else {
-                Some(None)
+                Some(RowInfo::default())
             }
         } else {
-            Some(self.input_buffer_rows.next().unwrap())
+            Some(self.input_rows.next().unwrap())
         }
     }
 }
@@ -1928,7 +1928,8 @@ fn offset_for_row(s: &str, target: u32) -> (u32, usize) {
 mod tests {
     use super::*;
     use crate::display_map::{
-        fold_map::FoldMap, inlay_map::InlayMap, tab_map::TabMap, wrap_map::WrapMap,
+        diff_map::DiffMap, fold_map::FoldMap, inlay_map::InlayMap, tab_map::TabMap,
+        wrap_map::WrapMap,
     };
     use gpui::{div, font, px, AppContext, Context as _, Element};
     use itertools::Itertools;
@@ -1962,7 +1963,8 @@ mod tests {
         let buffer = cx.update(|cx| MultiBuffer::build_simple(text, cx));
         let buffer_snapshot = cx.update(|cx| buffer.read(cx).snapshot(cx));
         let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
-        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (diff_map, diff_snapshot) = cx.update(|cx| DiffMap::new(buffer.clone(), cx));
+        let (mut inlay_map, inlay_snapshot) = InlayMap::new(diff_snapshot.clone());
         let (mut fold_map, fold_snapshot) = FoldMap::new(inlay_snapshot);
         let (mut tab_map, tab_snapshot) = TabMap::new(fold_snapshot, 1.try_into().unwrap());
         let (wrap_map, wraps_snapshot) =
@@ -2087,7 +2089,10 @@ mod tests {
         );
 
         assert_eq!(
-            snapshot.buffer_rows(BlockRow(0)).collect::<Vec<_>>(),
+            snapshot
+                .row_infos(BlockRow(0))
+                .map(|row_info| row_info.buffer_row)
+                .collect::<Vec<_>>(),
             &[
                 Some(0),
                 None,
@@ -2108,8 +2113,10 @@ mod tests {
             buffer.snapshot(cx)
         });
 
-        let (inlay_snapshot, inlay_edits) =
-            inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
+        let (diff_snapshot, diff_edits) = diff_map.update(cx, |diff_map, cx| {
+            diff_map.sync(buffer_snapshot, subscription.consume().into_inner(), cx)
+        });
+        let (inlay_snapshot, inlay_edits) = inlay_map.sync(diff_snapshot, diff_edits);
         let (fold_snapshot, fold_edits) = fold_map.read(inlay_snapshot, inlay_edits);
         let (tab_snapshot, tab_edits) =
             tab_map.sync(fold_snapshot, fold_edits, 4.try_into().unwrap());
@@ -2171,8 +2178,8 @@ mod tests {
                 .width;
         }
 
-        let multi_buffer_snapshot = multi_buffer.read(cx).snapshot(cx);
-        let (_, inlay_snapshot) = InlayMap::new(multi_buffer_snapshot.clone());
+        let (_, diff_snapshot) = DiffMap::new(multi_buffer.clone(), cx);
+        let (_, inlay_snapshot) = InlayMap::new(diff_snapshot);
         let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
         let (_, tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
         let (_, wraps_snapshot) = WrapMap::new(tab_snapshot, font, font_size, Some(wrap_width), cx);
@@ -2210,7 +2217,8 @@ mod tests {
         let buffer = cx.update(|cx| MultiBuffer::build_simple(text, cx));
         let buffer_snapshot = cx.update(|cx| buffer.read(cx).snapshot(cx));
         let _subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
-        let (_inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (_diff_map, diff_snapshot) = cx.update(|cx| DiffMap::new(buffer.clone(), cx));
+        let (_inlay_map, inlay_snapshot) = InlayMap::new(diff_snapshot.clone());
         let (_fold_map, fold_snapshot) = FoldMap::new(inlay_snapshot);
         let (_tab_map, tab_snapshot) = TabMap::new(fold_snapshot, 1.try_into().unwrap());
         let (_wrap_map, wraps_snapshot) =
@@ -2312,7 +2320,8 @@ mod tests {
 
         let buffer = cx.update(|cx| MultiBuffer::build_simple(text, cx));
         let buffer_snapshot = cx.update(|cx| buffer.read(cx).snapshot(cx));
-        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (_, diff_snapshot) = cx.update(|cx| DiffMap::new(buffer.clone(), cx));
+        let (_, inlay_snapshot) = InlayMap::new(diff_snapshot.clone());
         let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
         let (_, tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
         let (_, wraps_snapshot) = cx.update(|cx| {
@@ -2356,7 +2365,8 @@ mod tests {
         let buffer = cx.update(|cx| MultiBuffer::build_simple(text, cx));
         let buffer_subscription = buffer.update(cx, |buffer, _cx| buffer.subscribe());
         let buffer_snapshot = cx.update(|cx| buffer.read(cx).snapshot(cx));
-        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (diff_map, diff_snapshot) = cx.update(|cx| DiffMap::new(buffer.clone(), cx));
+        let (mut inlay_map, inlay_snapshot) = InlayMap::new(diff_snapshot.clone());
         let (mut fold_map, fold_snapshot) = FoldMap::new(inlay_snapshot);
         let tab_size = 1.try_into().unwrap();
         let (mut tab_map, tab_snapshot) = TabMap::new(fold_snapshot, tab_size);
@@ -2383,10 +2393,14 @@ mod tests {
             buffer.edit([(Point::new(2, 0)..Point::new(3, 0), "")], None, cx);
             buffer.snapshot(cx)
         });
-        let (inlay_snapshot, inlay_edits) = inlay_map.sync(
-            buffer_snapshot.clone(),
-            buffer_subscription.consume().into_inner(),
-        );
+        let (diff_snapshot, diff_edits) = diff_map.update(cx, |diff_map, cx| {
+            diff_map.sync(
+                buffer_snapshot,
+                buffer_subscription.consume().into_inner(),
+                cx,
+            )
+        });
+        let (inlay_snapshot, inlay_edits) = inlay_map.sync(diff_snapshot.clone(), diff_edits);
         let (fold_snapshot, fold_edits) = fold_map.read(inlay_snapshot, inlay_edits);
         let (tab_snapshot, tab_edits) = tab_map.sync(fold_snapshot, fold_edits, tab_size);
         let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
@@ -2406,10 +2420,14 @@ mod tests {
             );
             buffer.snapshot(cx)
         });
-        let (inlay_snapshot, inlay_edits) = inlay_map.sync(
-            buffer_snapshot.clone(),
-            buffer_subscription.consume().into_inner(),
-        );
+        let (diff_snapshot, diff_edits) = diff_map.update(cx, |diff_map, cx| {
+            diff_map.sync(
+                buffer_snapshot.clone(),
+                buffer_subscription.consume().into_inner(),
+                cx,
+            )
+        });
+        let (inlay_snapshot, inlay_edits) = inlay_map.sync(diff_snapshot, diff_edits);
         let (fold_snapshot, fold_edits) = fold_map.read(inlay_snapshot, inlay_edits);
         let (tab_snapshot, tab_edits) = tab_map.sync(fold_snapshot, fold_edits, tab_size);
         let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
@@ -2524,7 +2542,8 @@ mod tests {
         let buffer_id_2 = buffer_ids[1];
         let buffer_id_3 = buffer_ids[2];
 
-        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (_, diff_snapshot) = cx.update(|cx| DiffMap::new(buffer.clone(), cx));
+        let (_, inlay_snapshot) = InlayMap::new(diff_snapshot.clone());
         let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
         let (_, tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
         let (_, wrap_snapshot) =
@@ -2537,7 +2556,10 @@ mod tests {
             "\n\n\n111\n\n\n\n\n222\n\n\n333\n\n\n444\n\n\n\n\n555\n\n\n666\n"
         );
         assert_eq!(
-            blocks_snapshot.buffer_rows(BlockRow(0)).collect::<Vec<_>>(),
+            blocks_snapshot
+                .row_infos(BlockRow(0))
+                .map(|i| i.buffer_row)
+                .collect::<Vec<_>>(),
             vec![
                 None,
                 None,
@@ -2613,7 +2635,10 @@ mod tests {
             "\n\n\n111\n\n\n\n\n\n222\n\n\n\n333\n\n\n444\n\n\n\n\n\n\n555\n\n\n666\n\n"
         );
         assert_eq!(
-            blocks_snapshot.buffer_rows(BlockRow(0)).collect::<Vec<_>>(),
+            blocks_snapshot
+                .row_infos(BlockRow(0))
+                .map(|i| i.buffer_row)
+                .collect::<Vec<_>>(),
             vec![
                 None,
                 None,
@@ -2688,7 +2713,10 @@ mod tests {
             "\n\n\n\n\n\n222\n\n\n\n333\n\n\n444\n\n\n\n\n\n\n555\n\n\n666\n\n"
         );
         assert_eq!(
-            blocks_snapshot.buffer_rows(BlockRow(0)).collect::<Vec<_>>(),
+            blocks_snapshot
+                .row_infos(BlockRow(0))
+                .map(|i| i.buffer_row)
+                .collect::<Vec<_>>(),
             vec![
                 None,
                 None,
@@ -2753,7 +2781,10 @@ mod tests {
         );
         assert_eq!(blocks_snapshot.text(), "\n\n\n\n\n\n\n\n555\n\n\n666\n\n");
         assert_eq!(
-            blocks_snapshot.buffer_rows(BlockRow(0)).collect::<Vec<_>>(),
+            blocks_snapshot
+                .row_infos(BlockRow(0))
+                .map(|i| i.buffer_row)
+                .collect::<Vec<_>>(),
             vec![
                 None,
                 None,
@@ -2807,7 +2838,10 @@ mod tests {
             "Should have extra newline for 111 buffer, due to a new block added when it was folded"
         );
         assert_eq!(
-            blocks_snapshot.buffer_rows(BlockRow(0)).collect::<Vec<_>>(),
+            blocks_snapshot
+                .row_infos(BlockRow(0))
+                .map(|i| i.buffer_row)
+                .collect::<Vec<_>>(),
             vec![
                 None,
                 None,
@@ -2861,7 +2895,10 @@ mod tests {
             "Should have a single, first buffer left after folding"
         );
         assert_eq!(
-            blocks_snapshot.buffer_rows(BlockRow(0)).collect::<Vec<_>>(),
+            blocks_snapshot
+                .row_infos(BlockRow(0))
+                .map(|i| i.buffer_row)
+                .collect::<Vec<_>>(),
             vec![
                 None,
                 None,
@@ -2895,7 +2932,8 @@ mod tests {
         assert_eq!(buffer_ids.len(), 1);
         let buffer_id = buffer_ids[0];
 
-        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (_, diff_snapshot) = cx.update(|cx| DiffMap::new(buffer.clone(), cx));
+        let (_, inlay_snapshot) = InlayMap::new(diff_snapshot.clone());
         let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
         let (_, tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
         let (_, wrap_snapshot) =
@@ -2931,7 +2969,10 @@ mod tests {
         );
         assert_eq!(blocks_snapshot.text(), "\n");
         assert_eq!(
-            blocks_snapshot.buffer_rows(BlockRow(0)).collect::<Vec<_>>(),
+            blocks_snapshot
+                .row_infos(BlockRow(0))
+                .map(|i| i.buffer_row)
+                .collect::<Vec<_>>(),
             vec![None, None],
             "When fully folded, should be no buffer rows"
         );
@@ -2977,7 +3018,8 @@ mod tests {
         };
 
         let mut buffer_snapshot = cx.update(|cx| buffer.read(cx).snapshot(cx));
-        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (diff_map, diff_snapshot) = cx.update(|cx| DiffMap::new(buffer.clone(), cx));
+        let (mut inlay_map, inlay_snapshot) = InlayMap::new(diff_snapshot.clone());
         let (mut fold_map, fold_snapshot) = FoldMap::new(inlay_snapshot);
         let (mut tab_map, tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
         let (wrap_map, wraps_snapshot) = cx
@@ -3035,8 +3077,10 @@ mod tests {
                         })
                         .collect::<Vec<_>>();
 
-                    let (inlay_snapshot, inlay_edits) =
-                        inlay_map.sync(buffer_snapshot.clone(), vec![]);
+                    let (diff_snapshot, diff_edits) = diff_map.update(cx, |diff_map, cx| {
+                        diff_map.sync(buffer_snapshot.clone(), vec![], cx)
+                    });
+                    let (inlay_snapshot, inlay_edits) = inlay_map.sync(diff_snapshot, diff_edits);
                     let (fold_snapshot, fold_edits) = fold_map.read(inlay_snapshot, inlay_edits);
                     let (tab_snapshot, tab_edits) =
                         tab_map.sync(fold_snapshot, fold_edits, tab_size);
@@ -3073,8 +3117,10 @@ mod tests {
                         .map(|block| block.id)
                         .collect::<HashSet<_>>();
 
-                    let (inlay_snapshot, inlay_edits) =
-                        inlay_map.sync(buffer_snapshot.clone(), vec![]);
+                    let (diff_snapshot, diff_edits) = diff_map.update(cx, |diff_map, cx| {
+                        diff_map.sync(buffer_snapshot.clone(), vec![], cx)
+                    });
+                    let (inlay_snapshot, inlay_edits) = inlay_map.sync(diff_snapshot, diff_edits);
                     let (fold_snapshot, fold_edits) = fold_map.read(inlay_snapshot, inlay_edits);
                     let (tab_snapshot, tab_edits) =
                         tab_map.sync(fold_snapshot, fold_edits, tab_size);
@@ -3094,8 +3140,11 @@ mod tests {
                         log::info!("Noop fold/unfold operation on a singleton buffer");
                         continue;
                     }
+                    let (diff_snapshot, diff_edits) = diff_map.update(cx, |diff_map, cx| {
+                        diff_map.sync(buffer_snapshot.clone(), vec![], cx)
+                    });
                     let (inlay_snapshot, inlay_edits) =
-                        inlay_map.sync(buffer_snapshot.clone(), vec![]);
+                        inlay_map.sync(diff_snapshot.clone(), diff_edits);
                     let (fold_snapshot, fold_edits) = fold_map.read(inlay_snapshot, inlay_edits);
                     let (tab_snapshot, tab_edits) =
                         tab_map.sync(fold_snapshot, fold_edits, tab_size);
@@ -3180,8 +3229,10 @@ mod tests {
                 }
             }
 
-            let (inlay_snapshot, inlay_edits) =
-                inlay_map.sync(buffer_snapshot.clone(), buffer_edits);
+            let (diff_snapshot, diff_edits) = diff_map.update(cx, |diff_map, cx| {
+                diff_map.sync(buffer_snapshot.clone(), buffer_edits, cx)
+            });
+            let (inlay_snapshot, inlay_edits) = inlay_map.sync(diff_snapshot, diff_edits);
             let (fold_snapshot, fold_edits) = fold_map.read(inlay_snapshot, inlay_edits);
             let (tab_snapshot, tab_edits) = tab_map.sync(fold_snapshot, fold_edits, tab_size);
             let (wraps_snapshot, wrap_edits) = wrap_map.update(cx, |wrap_map, cx| {
@@ -3384,7 +3435,8 @@ mod tests {
                 );
                 assert_eq!(
                     blocks_snapshot
-                        .buffer_rows(BlockRow(start_row as u32))
+                        .row_infos(BlockRow(start_row as u32))
+                        .map(|row_info| row_info.buffer_row)
                         .collect::<Vec<_>>(),
                     &expected_buffer_rows[start_row..],
                     "incorrect buffer_rows starting at row {:?}",

crates/editor/src/display_map/fold_map.rs

@@ -1,3 +1,5 @@
+use crate::RowInfo;
+
 use super::{
     inlay_map::{InlayBufferRows, InlayChunks, InlayEdit, InlayOffset, InlayPoint, InlaySnapshot},
     Highlights,
@@ -139,7 +141,7 @@ impl<'a> FoldMapWriter<'a> {
         let mut folds = Vec::new();
         let snapshot = self.0.snapshot.inlay_snapshot.clone();
         for (range, fold_text) in ranges.into_iter() {
-            let buffer = &snapshot.buffer;
+            let buffer = snapshot.buffer();
             let range = range.start.to_offset(buffer)..range.end.to_offset(buffer);
 
             // Ignore any empty ranges.
@@ -161,14 +163,14 @@ impl<'a> FoldMapWriter<'a> {
             });
 
             let inlay_range =
-                snapshot.to_inlay_offset(range.start)..snapshot.to_inlay_offset(range.end);
+                snapshot.make_inlay_offset(range.start)..snapshot.make_inlay_offset(range.end);
             edits.push(InlayEdit {
                 old: inlay_range.clone(),
                 new: inlay_range,
             });
         }
 
-        let buffer = &snapshot.buffer;
+        let buffer = snapshot.buffer();
         folds.sort_unstable_by(|a, b| sum_tree::SeekTarget::cmp(&a.range, &b.range, buffer));
 
         self.0.snapshot.folds = {
@@ -220,7 +222,7 @@ impl<'a> FoldMapWriter<'a> {
         let mut edits = Vec::new();
         let mut fold_ixs_to_delete = Vec::new();
         let snapshot = self.0.snapshot.inlay_snapshot.clone();
-        let buffer = &snapshot.buffer;
+        let buffer = snapshot.buffer();
         for range in ranges.into_iter() {
             let range = range.start.to_offset(buffer)..range.end.to_offset(buffer);
             let mut folds_cursor =
@@ -230,8 +232,8 @@ impl<'a> FoldMapWriter<'a> {
                     fold.range.start.to_offset(buffer)..fold.range.end.to_offset(buffer);
                 if should_unfold(fold) {
                     if offset_range.end > offset_range.start {
-                        let inlay_range = snapshot.to_inlay_offset(offset_range.start)
-                            ..snapshot.to_inlay_offset(offset_range.end);
+                        let inlay_range = snapshot.make_inlay_offset(offset_range.start)
+                            ..snapshot.make_inlay_offset(offset_range.end);
                         edits.push(InlayEdit {
                             old: inlay_range.clone(),
                             new: inlay_range,
@@ -275,7 +277,7 @@ impl FoldMap {
     pub(crate) fn new(inlay_snapshot: InlaySnapshot) -> (Self, FoldSnapshot) {
         let this = Self {
             snapshot: FoldSnapshot {
-                folds: SumTree::new(&inlay_snapshot.buffer),
+                folds: SumTree::new(inlay_snapshot.buffer()),
                 transforms: SumTree::from_item(
                     Transform {
                         summary: TransformSummary {
@@ -336,9 +338,7 @@ impl FoldMap {
             let mut folds = self.snapshot.folds.iter().peekable();
             while let Some(fold) = folds.next() {
                 if let Some(next_fold) = folds.peek() {
-                    let comparison = fold
-                        .range
-                        .cmp(&next_fold.range, &self.snapshot.inlay_snapshot.buffer);
+                    let comparison = fold.range.cmp(&next_fold.range, self.snapshot.buffer());
                     assert!(comparison.is_le());
                 }
             }
@@ -410,31 +410,31 @@ impl FoldMap {
                     InlayOffset(((edit.new.start + edit.old_len()).0 as isize + delta) as usize);
 
                 let anchor = inlay_snapshot
-                    .buffer
+                    .buffer()
                     .anchor_before(inlay_snapshot.to_buffer_offset(edit.new.start));
                 let mut folds_cursor = self
                     .snapshot
                     .folds
-                    .cursor::<FoldRange>(&inlay_snapshot.buffer);
+                    .cursor::<FoldRange>(&inlay_snapshot.buffer());
                 folds_cursor.seek(
                     &FoldRange(anchor..Anchor::max()),
                     Bias::Left,
-                    &inlay_snapshot.buffer,
+                    &inlay_snapshot.buffer(),
                 );
 
                 let mut folds = iter::from_fn({
                     let inlay_snapshot = &inlay_snapshot;
                     move || {
                         let item = folds_cursor.item().map(|fold| {
-                            let buffer_start = fold.range.start.to_offset(&inlay_snapshot.buffer);
-                            let buffer_end = fold.range.end.to_offset(&inlay_snapshot.buffer);
+                            let buffer_start = fold.range.start.to_offset(&inlay_snapshot.buffer());
+                            let buffer_end = fold.range.end.to_offset(&inlay_snapshot.buffer());
                             (
                                 fold.clone(),
-                                inlay_snapshot.to_inlay_offset(buffer_start)
-                                    ..inlay_snapshot.to_inlay_offset(buffer_end),
+                                inlay_snapshot.make_inlay_offset(buffer_start)
+                                    ..inlay_snapshot.make_inlay_offset(buffer_end),
                             )
                         });
-                        folds_cursor.next(&inlay_snapshot.buffer);
+                        folds_cursor.next(&inlay_snapshot.buffer());
                         item
                     }
                 })
@@ -578,6 +578,10 @@ pub struct FoldSnapshot {
 }
 
 impl FoldSnapshot {
+    pub fn buffer(&self) -> &MultiBufferSnapshot {
+        self.inlay_snapshot.buffer()
+    }
+
     #[cfg(test)]
     pub fn text(&self) -> String {
         self.chunks(FoldOffset(0)..self.len(), false, Highlights::default())
@@ -587,7 +591,7 @@ impl FoldSnapshot {
 
     #[cfg(test)]
     pub fn fold_count(&self) -> usize {
-        self.folds.items(&self.inlay_snapshot.buffer).len()
+        self.folds.items(self.inlay_snapshot.buffer()).len()
     }
 
     pub fn text_summary_for_range(&self, range: Range<FoldPoint>) -> TextSummary {
@@ -641,6 +645,32 @@ impl FoldSnapshot {
         summary
     }
 
+    pub fn make_fold_point(&self, point: Point, bias: Bias) -> FoldPoint {
+        self.to_fold_point(self.inlay_snapshot.make_inlay_point(point), bias)
+    }
+
+    pub fn make_fold_offset(&self, buffer_offset: usize, bias: Bias) -> FoldOffset {
+        self.to_fold_offset(self.inlay_snapshot.make_inlay_offset(buffer_offset), bias)
+    }
+
+    pub fn to_fold_offset(&self, inlay_offset: InlayOffset, bias: Bias) -> FoldOffset {
+        let mut cursor = self.transforms.cursor::<(InlayOffset, FoldOffset)>(&());
+        cursor.seek(&inlay_offset, Bias::Right, &());
+        if cursor.item().map_or(false, |t| t.is_fold()) {
+            if bias == Bias::Left || inlay_offset == cursor.start().0 {
+                cursor.start().1
+            } else {
+                cursor.end(&()).1
+            }
+        } else {
+            let overshoot = inlay_offset.0 - cursor.start().0 .0;
+            FoldOffset(cmp::min(
+                cursor.start().1 .0 + overshoot,
+                cursor.end(&()).1 .0,
+            ))
+        }
+    }
+
     pub fn to_fold_point(&self, point: InlayPoint, bias: Bias) -> FoldPoint {
         let mut cursor = self.transforms.cursor::<(InlayPoint, FoldPoint)>(&());
         cursor.seek(&point, Bias::Right, &());
@@ -673,7 +703,7 @@ impl FoldSnapshot {
         (line_end - line_start) as u32
     }
 
-    pub fn buffer_rows(&self, start_row: u32) -> FoldBufferRows {
+    pub fn row_infos(&self, start_row: u32) -> FoldRows {
         if start_row > self.transforms.summary().output.lines.row {
             panic!("invalid display row {}", start_row);
         }
@@ -684,11 +714,11 @@ impl FoldSnapshot {
 
         let overshoot = fold_point.0 - cursor.start().0 .0;
         let inlay_point = InlayPoint(cursor.start().1 .0 + overshoot);
-        let input_buffer_rows = self.inlay_snapshot.buffer_rows(inlay_point.row());
+        let input_rows = self.inlay_snapshot.row_infos(inlay_point.row());
 
-        FoldBufferRows {
+        FoldRows {
             fold_point,
-            input_buffer_rows,
+            input_rows,
             cursor,
         }
     }
@@ -706,12 +736,12 @@ impl FoldSnapshot {
     where
         T: ToOffset,
     {
-        let buffer = &self.inlay_snapshot.buffer;
+        let buffer = self.inlay_snapshot.buffer();
         let range = range.start.to_offset(buffer)..range.end.to_offset(buffer);
         let mut folds = intersecting_folds(&self.inlay_snapshot, &self.folds, range, false);
         iter::from_fn(move || {
             let item = folds.item();
-            folds.next(&self.inlay_snapshot.buffer);
+            folds.next(buffer);
             item
         })
     }
@@ -720,8 +750,8 @@ impl FoldSnapshot {
     where
         T: ToOffset,
     {
-        let buffer_offset = offset.to_offset(&self.inlay_snapshot.buffer);
-        let inlay_offset = self.inlay_snapshot.to_inlay_offset(buffer_offset);
+        let buffer_offset = offset.to_offset(self.inlay_snapshot.buffer());
+        let inlay_offset = self.inlay_snapshot.make_inlay_offset(buffer_offset);
         let mut cursor = self.transforms.cursor::<InlayOffset>(&());
         cursor.seek(&inlay_offset, Bias::Right, &());
         cursor.item().map_or(false, |t| t.placeholder.is_some())
@@ -730,7 +760,7 @@ impl FoldSnapshot {
     pub fn is_line_folded(&self, buffer_row: MultiBufferRow) -> bool {
         let mut inlay_point = self
             .inlay_snapshot
-            .to_inlay_point(Point::new(buffer_row.0, 0));
+            .make_inlay_point(Point::new(buffer_row.0, 0));
         let mut cursor = self.transforms.cursor::<InlayPoint>(&());
         cursor.seek(&inlay_point, Bias::Right, &());
         loop {
@@ -870,7 +900,7 @@ fn intersecting_folds<'a>(
     range: Range<usize>,
     inclusive: bool,
 ) -> FilterCursor<'a, impl 'a + FnMut(&FoldSummary) -> bool, Fold, usize> {
-    let buffer = &inlay_snapshot.buffer;
+    let buffer = inlay_snapshot.buffer();
     let start = buffer.anchor_before(range.start.to_offset(buffer));
     let end = buffer.anchor_after(range.end.to_offset(buffer));
     let mut cursor = folds.filter::<_, usize>(buffer, move |summary| {
@@ -1134,25 +1164,25 @@ impl<'a> sum_tree::Dimension<'a, FoldSummary> for usize {
 }
 
 #[derive(Clone)]
-pub struct FoldBufferRows<'a> {
+pub struct FoldRows<'a> {
     cursor: Cursor<'a, Transform, (FoldPoint, InlayPoint)>,
-    input_buffer_rows: InlayBufferRows<'a>,
+    input_rows: InlayBufferRows<'a>,
     fold_point: FoldPoint,
 }
 
-impl<'a> FoldBufferRows<'a> {
+impl<'a> FoldRows<'a> {
     pub(crate) fn seek(&mut self, row: u32) {
         let fold_point = FoldPoint::new(row, 0);
         self.cursor.seek(&fold_point, Bias::Left, &());
         let overshoot = fold_point.0 - self.cursor.start().0 .0;
         let inlay_point = InlayPoint(self.cursor.start().1 .0 + overshoot);
-        self.input_buffer_rows.seek(inlay_point.row());
+        self.input_rows.seek(inlay_point.row());
         self.fold_point = fold_point;
     }
 }
 
-impl<'a> Iterator for FoldBufferRows<'a> {
-    type Item = Option<u32>;
+impl<'a> Iterator for FoldRows<'a> {
+    type Item = RowInfo;
 
     fn next(&mut self) -> Option<Self::Item> {
         let mut traversed_fold = false;
@@ -1166,11 +1196,11 @@ impl<'a> Iterator for FoldBufferRows<'a> {
 
         if self.cursor.item().is_some() {
             if traversed_fold {
-                self.input_buffer_rows.seek(self.cursor.start().1.row());
-                self.input_buffer_rows.next();
+                self.input_rows.seek(self.cursor.start().1 .0.row);
+                self.input_rows.next();
             }
             *self.fold_point.row_mut() += 1;
-            self.input_buffer_rows.next()
+            self.input_rows.next()
         } else {
             None
         }
@@ -1380,7 +1410,10 @@ pub type FoldEdit = Edit<FoldOffset>;
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::{display_map::inlay_map::InlayMap, MultiBuffer, ToPoint};
+    use crate::{
+        display_map::{diff_map::DiffMap, inlay_map::InlayMap},
+        MultiBuffer, ToPoint,
+    };
     use collections::HashSet;
     use rand::prelude::*;
     use settings::SettingsStore;
@@ -1395,8 +1428,8 @@ mod tests {
         init_test(cx);
         let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
         let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
-        let buffer_snapshot = buffer.read(cx).snapshot(cx);
-        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (diff_map, diff_snapshot) = DiffMap::new(buffer.clone(), cx);
+        let (mut inlay_map, inlay_snapshot) = InlayMap::new(diff_snapshot.clone());
         let mut map = FoldMap::new(inlay_snapshot.clone()).0;
 
         let (mut writer, _, _) = map.write(inlay_snapshot, vec![]);
@@ -1431,8 +1464,14 @@ mod tests {
             buffer.snapshot(cx)
         });
 
-        let (inlay_snapshot, inlay_edits) =
-            inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
+        let (diff_snapshot, diff_edits) = diff_map.update(cx, |diff_map, cx| {
+            diff_map.sync(
+                buffer_snapshot.clone(),
+                subscription.consume().into_inner(),
+                cx,
+            )
+        });
+        let (inlay_snapshot, inlay_edits) = inlay_map.sync(diff_snapshot, diff_edits);
         let (snapshot3, edits) = map.read(inlay_snapshot, inlay_edits);
         assert_eq!(snapshot3.text(), "123a⋯c123c⋯eeeee");
         assert_eq!(
@@ -1453,8 +1492,11 @@ mod tests {
             buffer.edit([(Point::new(2, 6)..Point::new(4, 3), "456")], None, cx);
             buffer.snapshot(cx)
         });
-        let (inlay_snapshot, inlay_edits) =
-            inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
+        let (diff_snapshot, diff_edits) = diff_map.update(cx, |diff_map, cx| {
+            diff_map.sync(buffer_snapshot, subscription.consume().into_inner(), cx)
+        });
+
+        let (inlay_snapshot, inlay_edits) = inlay_map.sync(diff_snapshot, diff_edits);
         let (snapshot4, _) = map.read(inlay_snapshot.clone(), inlay_edits);
         assert_eq!(snapshot4.text(), "123a⋯c123456eee");
 
@@ -1474,8 +1516,8 @@ mod tests {
         init_test(cx);
         let buffer = MultiBuffer::build_simple("abcdefghijkl", cx);
         let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
-        let buffer_snapshot = buffer.read(cx).snapshot(cx);
-        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (diff_map, diff_snapshot) = DiffMap::new(buffer.clone(), cx);
+        let (mut inlay_map, inlay_snapshot) = InlayMap::new(diff_snapshot.clone());
 
         {
             let mut map = FoldMap::new(inlay_snapshot.clone()).0;
@@ -1521,8 +1563,10 @@ mod tests {
                 buffer.edit([(0..1, "12345")], None, cx);
                 buffer.snapshot(cx)
             });
-            let (inlay_snapshot, inlay_edits) =
-                inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
+            let (diff_snapshot, diff_edits) = diff_map.update(cx, |diff_map, cx| {
+                diff_map.sync(buffer_snapshot, subscription.consume().into_inner(), cx)
+            });
+            let (inlay_snapshot, inlay_edits) = inlay_map.sync(diff_snapshot, diff_edits);
             let (snapshot, _) = map.read(inlay_snapshot, inlay_edits);
             assert_eq!(snapshot.text(), "12345⋯fghijkl");
         }
@@ -1531,8 +1575,8 @@ mod tests {
     #[gpui::test]
     fn test_overlapping_folds(cx: &mut gpui::AppContext) {
         let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
-        let buffer_snapshot = buffer.read(cx).snapshot(cx);
-        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot);
+        let (_, diff_snapshot) = DiffMap::new(buffer.clone(), cx);
+        let (_, inlay_snapshot) = InlayMap::new(diff_snapshot);
         let mut map = FoldMap::new(inlay_snapshot.clone()).0;
         let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
         writer.fold(vec![
@@ -1550,8 +1594,8 @@ mod tests {
         init_test(cx);
         let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
         let subscription = buffer.update(cx, |buffer, _| buffer.subscribe());
-        let buffer_snapshot = buffer.read(cx).snapshot(cx);
-        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (diff_map, diff_snapshot) = DiffMap::new(buffer.clone(), cx);
+        let (mut inlay_map, inlay_snapshot) = InlayMap::new(diff_snapshot.clone());
         let mut map = FoldMap::new(inlay_snapshot.clone()).0;
 
         let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
@@ -1566,8 +1610,10 @@ mod tests {
             buffer.edit([(Point::new(2, 2)..Point::new(3, 1), "")], None, cx);
             buffer.snapshot(cx)
         });
-        let (inlay_snapshot, inlay_edits) =
-            inlay_map.sync(buffer_snapshot, subscription.consume().into_inner());
+        let (diff_snapshot, diff_edits) = diff_map.update(cx, |diff_map, cx| {
+            diff_map.sync(buffer_snapshot, subscription.consume().into_inner(), cx)
+        });
+        let (inlay_snapshot, inlay_edits) = inlay_map.sync(diff_snapshot, diff_edits);
         let (snapshot, _) = map.read(inlay_snapshot, inlay_edits);
         assert_eq!(snapshot.text(), "aa⋯eeeee");
     }
@@ -1576,7 +1622,8 @@ mod tests {
     fn test_folds_in_range(cx: &mut gpui::AppContext) {
         let buffer = MultiBuffer::build_simple(&sample_text(5, 6, 'a'), cx);
         let buffer_snapshot = buffer.read(cx).snapshot(cx);
-        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (_, diff_snapshot) = DiffMap::new(buffer.clone(), cx);
+        let (_, inlay_snapshot) = InlayMap::new(diff_snapshot.clone());
         let mut map = FoldMap::new(inlay_snapshot.clone()).0;
 
         let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
@@ -1618,7 +1665,8 @@ mod tests {
             MultiBuffer::build_random(&mut rng, cx)
         };
         let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
-        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (diff_map, diff_snapshot) = DiffMap::new(buffer.clone(), cx);
+        let (mut inlay_map, inlay_snapshot) = InlayMap::new(diff_snapshot.clone());
         let mut map = FoldMap::new(inlay_snapshot.clone()).0;
 
         let (mut initial_snapshot, _) = map.read(inlay_snapshot.clone(), vec![]);
@@ -1648,8 +1696,10 @@ mod tests {
                 }),
             };
 
-            let (inlay_snapshot, new_inlay_edits) =
-                inlay_map.sync(buffer_snapshot.clone(), buffer_edits);
+            let (diff_snapshot, diff_edits) = diff_map.update(cx, |diff_map, cx| {
+                diff_map.sync(buffer_snapshot.clone(), buffer_edits, cx)
+            });
+            let (inlay_snapshot, new_inlay_edits) = inlay_map.sync(diff_snapshot, diff_edits);
             log::info!("inlay text {:?}", inlay_snapshot.text());
 
             let inlay_edits = Patch::new(inlay_edits)
@@ -1660,8 +1710,8 @@ mod tests {
 
             let mut expected_text: String = inlay_snapshot.text().to_string();
             for fold_range in map.merged_folds().into_iter().rev() {
-                let fold_inlay_start = inlay_snapshot.to_inlay_offset(fold_range.start);
-                let fold_inlay_end = inlay_snapshot.to_inlay_offset(fold_range.end);
+                let fold_inlay_start = inlay_snapshot.make_inlay_offset(fold_range.start);
+                let fold_inlay_end = inlay_snapshot.make_inlay_offset(fold_range.end);
                 expected_text.replace_range(fold_inlay_start.0..fold_inlay_end.0, "⋯");
             }
 
@@ -1676,19 +1726,19 @@ mod tests {
             let mut expected_buffer_rows = Vec::new();
             for fold_range in map.merged_folds() {
                 let fold_start = inlay_snapshot
-                    .to_point(inlay_snapshot.to_inlay_offset(fold_range.start))
+                    .to_point(inlay_snapshot.make_inlay_offset(fold_range.start))
                     .row();
                 let fold_end = inlay_snapshot
-                    .to_point(inlay_snapshot.to_inlay_offset(fold_range.end))
+                    .to_point(inlay_snapshot.make_inlay_offset(fold_range.end))
                     .row();
                 expected_buffer_rows.extend(
                     inlay_snapshot
-                        .buffer_rows(prev_row)
+                        .row_infos(prev_row)
                         .take((1 + fold_start - prev_row) as usize),
                 );
                 prev_row = 1 + fold_end;
             }
-            expected_buffer_rows.extend(inlay_snapshot.buffer_rows(prev_row));
+            expected_buffer_rows.extend(inlay_snapshot.row_infos(prev_row));
 
             assert_eq!(
                 expected_buffer_rows.len(),
@@ -1777,7 +1827,7 @@ mod tests {
             let mut fold_row = 0;
             while fold_row < expected_buffer_rows.len() as u32 {
                 assert_eq!(
-                    snapshot.buffer_rows(fold_row).collect::<Vec<_>>(),
+                    snapshot.row_infos(fold_row).collect::<Vec<_>>(),
                     expected_buffer_rows[(fold_row as usize)..],
                     "wrong buffer rows starting at fold row {}",
                     fold_row,
@@ -1879,8 +1929,8 @@ mod tests {
         let text = sample_text(6, 6, 'a') + "\n";
         let buffer = MultiBuffer::build_simple(&text, cx);
 
-        let buffer_snapshot = buffer.read(cx).snapshot(cx);
-        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot);
+        let (_, diff_snapshot) = DiffMap::new(buffer.clone(), cx);
+        let (_, inlay_snapshot) = InlayMap::new(diff_snapshot);
         let mut map = FoldMap::new(inlay_snapshot.clone()).0;
 
         let (mut writer, _, _) = map.write(inlay_snapshot.clone(), vec![]);
@@ -1892,10 +1942,19 @@ mod tests {
         let (snapshot, _) = map.read(inlay_snapshot, vec![]);
         assert_eq!(snapshot.text(), "aa⋯cccc\nd⋯eeeee\nffffff\n");
         assert_eq!(
-            snapshot.buffer_rows(0).collect::<Vec<_>>(),
+            snapshot
+                .row_infos(0)
+                .map(|info| info.buffer_row)
+                .collect::<Vec<_>>(),
             [Some(0), Some(3), Some(5), Some(6)]
         );
-        assert_eq!(snapshot.buffer_rows(3).collect::<Vec<_>>(), [Some(6)]);
+        assert_eq!(
+            snapshot
+                .row_infos(3)
+                .map(|info| info.buffer_row)
+                .collect::<Vec<_>>(),
+            [Some(6)]
+        );
     }
 
     fn init_test(cx: &mut gpui::AppContext) {
@@ -1906,7 +1965,7 @@ mod tests {
     impl FoldMap {
         fn merged_folds(&self) -> Vec<Range<usize>> {
             let inlay_snapshot = self.snapshot.inlay_snapshot.clone();
-            let buffer = &inlay_snapshot.buffer;
+            let buffer = inlay_snapshot.buffer();
             let mut folds = self.snapshot.folds.items(buffer);
             // Ensure sorting doesn't change how folds get merged and displayed.
             folds.sort_by(|a, b| a.range.cmp(&b.range, buffer));
@@ -1942,7 +2001,7 @@ mod tests {
             match rng.gen_range(0..=100) {
                 0..=39 if !self.snapshot.folds.is_empty() => {
                     let inlay_snapshot = self.snapshot.inlay_snapshot.clone();
-                    let buffer = &inlay_snapshot.buffer;
+                    let buffer = inlay_snapshot.buffer();
                     let mut to_unfold = Vec::new();
                     for _ in 0..rng.gen_range(1..=3) {
                         let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);
@@ -1958,7 +2017,7 @@ mod tests {
                 }
                 _ => {
                     let inlay_snapshot = self.snapshot.inlay_snapshot.clone();
-                    let buffer = &inlay_snapshot.buffer;
+                    let buffer = inlay_snapshot.buffer();
                     let mut to_fold = Vec::new();
                     for _ in 0..rng.gen_range(1..=2) {
                         let end = buffer.clip_offset(rng.gen_range(0..=buffer.len()), Right);

crates/editor/src/display_map/inlay_map.rs

@@ -1,7 +1,7 @@
-use crate::{HighlightStyles, InlayId};
+use crate::{HighlightStyles, InlayId, RowInfo};
 use collections::BTreeSet;
 use language::{Chunk, Edit, Point, TextSummary};
-use multi_buffer::{Anchor, MultiBufferRow, MultiBufferRows, MultiBufferSnapshot, ToOffset};
+use multi_buffer::{Anchor, MultiBufferSnapshot, ToOffset};
 use std::{
     cmp,
     ops::{Add, AddAssign, Range, Sub, SubAssign},
@@ -9,7 +9,10 @@ use std::{
 use sum_tree::{Bias, Cursor, SumTree};
 use text::{Patch, Rope};
 
-use super::{custom_highlights::CustomHighlightsChunks, Highlights};
+use super::{
+    diff_map::{DiffEdit, DiffMapChunks, DiffMapRows, DiffMapSnapshot, DiffOffset, DiffPoint},
+    Highlights,
+};
 
 /// Decides where the [`Inlay`]s should be displayed.
 ///
@@ -21,7 +24,7 @@ pub struct InlayMap {
 
 #[derive(Clone)]
 pub struct InlaySnapshot {
-    pub buffer: MultiBufferSnapshot,
+    pub diff_map_snapshot: DiffMapSnapshot,
     transforms: SumTree<Transform>,
     pub version: usize,
 }
@@ -172,37 +175,37 @@ impl<'a> sum_tree::Dimension<'a, TransformSummary> for InlayPoint {
     }
 }
 
-impl<'a> sum_tree::Dimension<'a, TransformSummary> for usize {
+impl<'a> sum_tree::Dimension<'a, TransformSummary> for DiffOffset {
     fn zero(_cx: &()) -> Self {
-        Default::default()
+        DiffOffset(0)
     }
 
     fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
-        *self += &summary.input.len;
+        self.0 += &summary.input.len;
     }
 }
 
-impl<'a> sum_tree::Dimension<'a, TransformSummary> for Point {
+impl<'a> sum_tree::Dimension<'a, TransformSummary> for DiffPoint {
     fn zero(_cx: &()) -> Self {
         Default::default()
     }
 
     fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
-        *self += &summary.input.lines;
+        self.0 += &summary.input.lines;
     }
 }
 
 #[derive(Clone)]
 pub struct InlayBufferRows<'a> {
-    transforms: Cursor<'a, Transform, (InlayPoint, Point)>,
-    buffer_rows: MultiBufferRows<'a>,
+    transforms: Cursor<'a, Transform, (InlayPoint, DiffPoint)>,
+    diff_rows: DiffMapRows<'a>,
     inlay_row: u32,
-    max_buffer_row: MultiBufferRow,
+    max_point: DiffPoint,
 }
 
 pub struct InlayChunks<'a> {
-    transforms: Cursor<'a, Transform, (InlayOffset, usize)>,
-    buffer_chunks: CustomHighlightsChunks<'a>,
+    transforms: Cursor<'a, Transform, (InlayOffset, DiffOffset)>,
+    diff_map_chunks: DiffMapChunks<'a>,
     buffer_chunk: Option<Chunk<'a>>,
     inlay_chunks: Option<text::Chunks<'a>>,
     inlay_chunk: Option<&'a str>,
@@ -214,21 +217,21 @@ pub struct InlayChunks<'a> {
 }
 
 impl<'a> InlayChunks<'a> {
+    pub fn offset(&self) -> InlayOffset {
+        self.output_offset
+    }
+
     pub fn seek(&mut self, new_range: Range<InlayOffset>) {
         self.transforms.seek(&new_range.start, Bias::Right, &());
 
-        let buffer_range = self.snapshot.to_buffer_offset(new_range.start)
-            ..self.snapshot.to_buffer_offset(new_range.end);
-        self.buffer_chunks.seek(buffer_range);
+        let diff_range = self.snapshot.to_diff_offset(new_range.start)
+            ..self.snapshot.to_diff_offset(new_range.end);
+        self.diff_map_chunks.seek(diff_range);
         self.inlay_chunks = None;
         self.buffer_chunk = None;
         self.output_offset = new_range.start;
         self.max_output_offset = new_range.end;
     }
-
-    pub fn offset(&self) -> InlayOffset {
-        self.output_offset
-    }
 }
 
 impl<'a> Iterator for InlayChunks<'a> {
@@ -243,9 +246,9 @@ impl<'a> Iterator for InlayChunks<'a> {
             Transform::Isomorphic(_) => {
                 let chunk = self
                     .buffer_chunk
-                    .get_or_insert_with(|| self.buffer_chunks.next().unwrap());
+                    .get_or_insert_with(|| self.diff_map_chunks.next().unwrap());
                 if chunk.text.is_empty() {
-                    *chunk = self.buffer_chunks.next().unwrap();
+                    *chunk = self.diff_map_chunks.next().unwrap();
                 }
 
                 let (prefix, suffix) = chunk.text.split_at(
@@ -344,33 +347,33 @@ impl<'a> InlayBufferRows<'a> {
         let inlay_point = InlayPoint::new(row, 0);
         self.transforms.seek(&inlay_point, Bias::Left, &());
 
-        let mut buffer_point = self.transforms.start().1;
-        let buffer_row = MultiBufferRow(if row == 0 {
+        let mut diff_point = self.transforms.start().1;
+        let row = if row == 0 {
             0
         } else {
             match self.transforms.item() {
                 Some(Transform::Isomorphic(_)) => {
-                    buffer_point += inlay_point.0 - self.transforms.start().0 .0;
-                    buffer_point.row
+                    diff_point.0 += inlay_point.0 - self.transforms.start().0 .0;
+                    diff_point.row()
                 }
-                _ => cmp::min(buffer_point.row + 1, self.max_buffer_row.0),
+                _ => cmp::min(diff_point.row() + 1, self.max_point.row()),
             }
-        });
+        };
         self.inlay_row = inlay_point.row();
-        self.buffer_rows.seek(buffer_row);
+        self.diff_rows.seek(row);
     }
 }
 
 impl<'a> Iterator for InlayBufferRows<'a> {
-    type Item = Option<u32>;
+    type Item = RowInfo;
 
     fn next(&mut self) -> Option<Self::Item> {
-        let buffer_row = if self.inlay_row == 0 {
-            self.buffer_rows.next().unwrap()
+        let row_info = if self.inlay_row == 0 {
+            self.diff_rows.next().unwrap()
         } else {
             match self.transforms.item()? {
-                Transform::Inlay(_) => None,
-                Transform::Isomorphic(_) => self.buffer_rows.next().unwrap(),
+                Transform::Inlay(_) => Default::default(),
+                Transform::Isomorphic(_) => self.diff_rows.next().unwrap(),
             }
         };
 
@@ -378,7 +381,7 @@ impl<'a> Iterator for InlayBufferRows<'a> {
         self.transforms
             .seek_forward(&InlayPoint::new(self.inlay_row, 0), Bias::Left, &());
 
-        Some(buffer_row)
+        Some(row_info)
     }
 }
 
@@ -393,11 +396,14 @@ impl InlayPoint {
 }
 
 impl InlayMap {
-    pub fn new(buffer: MultiBufferSnapshot) -> (Self, InlaySnapshot) {
+    pub fn new(diff_map_snapshot: DiffMapSnapshot) -> (Self, InlaySnapshot) {
         let version = 0;
         let snapshot = InlaySnapshot {
-            buffer: buffer.clone(),
-            transforms: SumTree::from_iter(Some(Transform::Isomorphic(buffer.text_summary())), &()),
+            transforms: SumTree::from_iter(
+                Some(Transform::Isomorphic(diff_map_snapshot.text_summary())),
+                &(),
+            ),
+            diff_map_snapshot,
             version,
         };
 
@@ -412,133 +418,121 @@ impl InlayMap {
 
     pub fn sync(
         &mut self,
-        buffer_snapshot: MultiBufferSnapshot,
-        mut buffer_edits: Vec<text::Edit<usize>>,
+        diff_map_snapshot: DiffMapSnapshot,
+        mut diff_edits: Vec<DiffEdit>,
     ) -> (InlaySnapshot, Vec<InlayEdit>) {
         let snapshot = &mut self.snapshot;
 
-        if buffer_edits.is_empty()
-            && snapshot.buffer.trailing_excerpt_update_count()
-                != buffer_snapshot.trailing_excerpt_update_count()
+        if diff_edits.is_empty()
+            && snapshot.buffer().trailing_excerpt_update_count()
+                != diff_map_snapshot.buffer().trailing_excerpt_update_count()
         {
-            buffer_edits.push(Edit {
-                old: snapshot.buffer.len()..snapshot.buffer.len(),
-                new: buffer_snapshot.len()..buffer_snapshot.len(),
+            diff_edits.push(Edit {
+                old: snapshot.diff_map_snapshot.len()..snapshot.diff_map_snapshot.len(),
+                new: diff_map_snapshot.len()..diff_map_snapshot.len(),
             });
         }
 
-        if buffer_edits.is_empty() {
-            if snapshot.buffer.edit_count() != buffer_snapshot.edit_count()
-                || snapshot.buffer.non_text_state_update_count()
-                    != buffer_snapshot.non_text_state_update_count()
-                || snapshot.buffer.trailing_excerpt_update_count()
-                    != buffer_snapshot.trailing_excerpt_update_count()
-            {
-                snapshot.version += 1;
-            }
-
-            snapshot.buffer = buffer_snapshot;
-            (snapshot.clone(), Vec::new())
-        } else {
-            let mut inlay_edits = Patch::default();
-            let mut new_transforms = SumTree::default();
-            let mut cursor = snapshot.transforms.cursor::<(usize, InlayOffset)>(&());
-            let mut buffer_edits_iter = buffer_edits.iter().peekable();
-            while let Some(buffer_edit) = buffer_edits_iter.next() {
-                new_transforms.append(cursor.slice(&buffer_edit.old.start, Bias::Left, &()), &());
-                if let Some(Transform::Isomorphic(transform)) = cursor.item() {
-                    if cursor.end(&()).0 == buffer_edit.old.start {
-                        push_isomorphic(&mut new_transforms, transform.clone());
-                        cursor.next(&());
-                    }
-                }
-
-                // Remove all the inlays and transforms contained by the edit.
-                let old_start =
-                    cursor.start().1 + InlayOffset(buffer_edit.old.start - cursor.start().0);
-                cursor.seek(&buffer_edit.old.end, Bias::Right, &());
-                let old_end =
-                    cursor.start().1 + InlayOffset(buffer_edit.old.end - cursor.start().0);
-
-                // Push the unchanged prefix.
-                let prefix_start = new_transforms.summary().input.len;
-                let prefix_end = buffer_edit.new.start;
-                push_isomorphic(
-                    &mut new_transforms,
-                    buffer_snapshot.text_summary_for_range(prefix_start..prefix_end),
-                );
-                let new_start = InlayOffset(new_transforms.summary().output.len);
-
-                let start_ix = match self.inlays.binary_search_by(|probe| {
-                    probe
-                        .position
-                        .to_offset(&buffer_snapshot)
-                        .cmp(&buffer_edit.new.start)
-                        .then(std::cmp::Ordering::Greater)
-                }) {
-                    Ok(ix) | Err(ix) => ix,
-                };
-
-                for inlay in &self.inlays[start_ix..] {
-                    let buffer_offset = inlay.position.to_offset(&buffer_snapshot);
-                    if buffer_offset > buffer_edit.new.end {
-                        break;
-                    }
-
-                    let prefix_start = new_transforms.summary().input.len;
-                    let prefix_end = buffer_offset;
-                    push_isomorphic(
-                        &mut new_transforms,
-                        buffer_snapshot.text_summary_for_range(prefix_start..prefix_end),
-                    );
-
-                    if inlay.position.is_valid(&buffer_snapshot) {
-                        new_transforms.push(Transform::Inlay(inlay.clone()), &());
-                    }
-                }
-
-                // Apply the rest of the edit.
-                let transform_start = new_transforms.summary().input.len;
-                push_isomorphic(
-                    &mut new_transforms,
-                    buffer_snapshot.text_summary_for_range(transform_start..buffer_edit.new.end),
-                );
-                let new_end = InlayOffset(new_transforms.summary().output.len);
-                inlay_edits.push(Edit {
-                    old: old_start..old_end,
-                    new: new_start..new_end,
-                });
-
-                // If the next edit doesn't intersect the current isomorphic transform, then
-                // we can push its remainder.
-                if buffer_edits_iter
-                    .peek()
-                    .map_or(true, |edit| edit.old.start >= cursor.end(&()).0)
-                {
-                    let transform_start = new_transforms.summary().input.len;
-                    let transform_end =
-                        buffer_edit.new.end + (cursor.end(&()).0 - buffer_edit.old.end);
-                    push_isomorphic(
-                        &mut new_transforms,
-                        buffer_snapshot.text_summary_for_range(transform_start..transform_end),
-                    );
+        let mut inlay_edits = Patch::default();
+        let mut new_transforms = SumTree::default();
+        let mut cursor = snapshot.transforms.cursor::<(DiffOffset, InlayOffset)>(&());
+        let mut diff_edits_iter = diff_edits.iter().peekable();
+        while let Some(diff_edit) = diff_edits_iter.next() {
+            new_transforms.append(cursor.slice(&diff_edit.old.start, Bias::Left, &()), &());
+            if let Some(Transform::Isomorphic(transform)) = cursor.item() {
+                if cursor.end(&()).0 == diff_edit.old.start {
+                    push_isomorphic(&mut new_transforms, transform.clone());
                     cursor.next(&());
                 }
             }
 
-            new_transforms.append(cursor.suffix(&()), &());
-            if new_transforms.is_empty() {
-                new_transforms.push(Transform::Isomorphic(Default::default()), &());
+            // Remove all the inlays and transforms contained by the edit.
+            let old_start =
+                cursor.start().1 + InlayOffset((diff_edit.old.start - cursor.start().0).0);
+            cursor.seek(&diff_edit.old.end, Bias::Right, &());
+            let old_end = cursor.start().1 + InlayOffset((diff_edit.old.end - cursor.start().0).0);
+
+            // Push the unchanged prefix.
+            let prefix_start = DiffOffset(new_transforms.summary().input.len);
+            let prefix_end = diff_edit.new.start;
+            push_isomorphic(
+                &mut new_transforms,
+                diff_map_snapshot.text_summary_for_range(prefix_start..prefix_end),
+            );
+            let new_start = InlayOffset(new_transforms.summary().output.len);
+
+            let edit_buffer_range = diff_map_snapshot.to_multibuffer_offset(diff_edit.new.start)
+                ..diff_map_snapshot.to_multibuffer_offset(diff_edit.new.end);
+
+            let start_ix = match self.inlays.binary_search_by(|probe| {
+                probe
+                    .position
+                    .to_offset(diff_map_snapshot.buffer())
+                    .cmp(&edit_buffer_range.start)
+                    .then(std::cmp::Ordering::Greater)
+            }) {
+                Ok(ix) | Err(ix) => ix,
+            };
+
+            for inlay in &self.inlays[start_ix..] {
+                let buffer_offset = inlay.position.to_offset(&diff_map_snapshot.buffer);
+                let diff_offset = diff_map_snapshot.to_diff_offset(buffer_offset);
+                if buffer_offset > edit_buffer_range.end {
+                    break;
+                }
+
+                let prefix_start = DiffOffset(new_transforms.summary().input.len);
+                let prefix_end = diff_offset;
+                push_isomorphic(
+                    &mut new_transforms,
+                    diff_map_snapshot.text_summary_for_range(prefix_start..prefix_end),
+                );
+
+                if inlay.position.is_valid(&diff_map_snapshot.buffer) {
+                    new_transforms.push(Transform::Inlay(inlay.clone()), &());
+                }
             }
 
-            drop(cursor);
-            snapshot.transforms = new_transforms;
-            snapshot.version += 1;
-            snapshot.buffer = buffer_snapshot;
-            snapshot.check_invariants();
+            // Apply the rest of the edit.
+            let transform_start = DiffOffset(new_transforms.summary().input.len);
+            push_isomorphic(
+                &mut new_transforms,
+                diff_map_snapshot.text_summary_for_range(transform_start..diff_edit.new.end),
+            );
+            let new_end = InlayOffset(new_transforms.summary().output.len);
+            inlay_edits.push(Edit {
+                old: old_start..old_end,
+                new: new_start..new_end,
+            });
 
-            (snapshot.clone(), inlay_edits.into_inner())
+            // If the next edit doesn't intersect the current isomorphic transform, then
+            // we can push its remainder.
+            if diff_edits_iter
+                .peek()
+                .map_or(true, |edit| edit.old.start >= cursor.end(&()).0)
+            {
+                let transform_start = DiffOffset(new_transforms.summary().input.len);
+                let transform_end = diff_edit.new.end + (cursor.end(&()).0 - diff_edit.old.end);
+                push_isomorphic(
+                    &mut new_transforms,
+                    diff_map_snapshot.text_summary_for_range(transform_start..transform_end),
+                );
+                cursor.next(&());
+            }
         }
+
+        new_transforms.append(cursor.suffix(&()), &());
+        if new_transforms.is_empty() {
+            new_transforms.push(Transform::Isomorphic(Default::default()), &());
+        }
+
+        drop(cursor);
+        snapshot.transforms = new_transforms;
+        snapshot.version += 1;
+        snapshot.diff_map_snapshot = diff_map_snapshot;
+        snapshot.check_invariants();
+
+        (snapshot.clone(), inlay_edits.into_inner())
     }
 
     pub fn splice(
@@ -552,7 +546,9 @@ impl InlayMap {
         self.inlays.retain(|inlay| {
             let retain = !to_remove.contains(&inlay.id);
             if !retain {
-                let offset = inlay.position.to_offset(&snapshot.buffer);
+                let offset = snapshot
+                    .diff_map_snapshot
+                    .to_diff_offset(inlay.position.to_offset(&snapshot.diff_map_snapshot.buffer));
                 edits.insert(offset);
             }
             retain
@@ -564,11 +560,16 @@ impl InlayMap {
                 continue;
             }
 
-            let offset = inlay_to_insert.position.to_offset(&snapshot.buffer);
-            match self.inlays.binary_search_by(|probe| {
-                probe
+            let offset = snapshot.diff_map_snapshot.to_diff_offset(
+                inlay_to_insert
                     .position
-                    .cmp(&inlay_to_insert.position, &snapshot.buffer)
+                    .to_offset(&snapshot.diff_map_snapshot.buffer),
+            );
+            match self.inlays.binary_search_by(|probe| {
+                probe.position.cmp(
+                    &inlay_to_insert.position,
+                    &snapshot.diff_map_snapshot.buffer,
+                )
             }) {
                 Ok(ix) | Err(ix) => {
                     self.inlays.insert(ix, inlay_to_insert);
@@ -585,7 +586,7 @@ impl InlayMap {
                 new: offset..offset,
             })
             .collect();
-        let buffer_snapshot = snapshot.buffer.clone();
+        let buffer_snapshot = snapshot.diff_map_snapshot.clone();
         let (snapshot, edits) = self.sync(buffer_snapshot, buffer_edits);
         (snapshot, edits)
     }
@@ -608,7 +609,8 @@ impl InlayMap {
         let snapshot = &mut self.snapshot;
         for i in 0..rng.gen_range(1..=5) {
             if self.inlays.is_empty() || rng.gen() {
-                let position = snapshot.buffer.random_byte_range(0, rng).start;
+                let position = snapshot.buffer().random_byte_range(0, rng).start;
+                let anchor = snapshot.buffer().anchor_at(position, Bias::Left);
                 let bias = if rng.gen() { Bias::Left } else { Bias::Right };
                 let len = if rng.gen_bool(0.01) {
                     0
@@ -626,7 +628,7 @@ impl InlayMap {
                     InlayId::InlineCompletion(post_inc(next_inlay_id))
                 };
                 log::info!(
-                    "creating inlay {:?} at buffer offset {} with bias {:?} and text {:?}",
+                    "creating inlay {:?} at buffer offset {:?} with bias {:?} and text {:?}",
                     inlay_id,
                     position,
                     bias,
@@ -635,7 +637,7 @@ impl InlayMap {
 
                 to_insert.push(Inlay {
                     id: inlay_id,
-                    position: snapshot.buffer.anchor_at(position, bias),
+                    position: anchor,
                     text: text.into(),
                 });
             } else {
@@ -659,16 +661,16 @@ impl InlaySnapshot {
     pub fn to_point(&self, offset: InlayOffset) -> InlayPoint {
         let mut cursor = self
             .transforms
-            .cursor::<(InlayOffset, (InlayPoint, usize))>(&());
+            .cursor::<(InlayOffset, (InlayPoint, DiffOffset))>(&());
         cursor.seek(&offset, Bias::Right, &());
         let overshoot = offset.0 - cursor.start().0 .0;
         match cursor.item() {
             Some(Transform::Isomorphic(_)) => {
                 let buffer_offset_start = cursor.start().1 .1;
-                let buffer_offset_end = buffer_offset_start + overshoot;
-                let buffer_start = self.buffer.offset_to_point(buffer_offset_start);
-                let buffer_end = self.buffer.offset_to_point(buffer_offset_end);
-                InlayPoint(cursor.start().1 .0 .0 + (buffer_end - buffer_start))
+                let buffer_offset_end = buffer_offset_start + DiffOffset(overshoot);
+                let buffer_start = self.diff_map_snapshot.offset_to_point(buffer_offset_start);
+                let buffer_end = self.diff_map_snapshot.offset_to_point(buffer_offset_end);
+                cursor.start().1 .0 + InlayPoint(buffer_end.0 - buffer_start.0)
             }
             Some(Transform::Inlay(inlay)) => {
                 let overshoot = inlay.text.offset_to_point(overshoot);
@@ -689,51 +691,68 @@ impl InlaySnapshot {
     pub fn to_offset(&self, point: InlayPoint) -> InlayOffset {
         let mut cursor = self
             .transforms
-            .cursor::<(InlayPoint, (InlayOffset, Point))>(&());
+            .cursor::<(InlayPoint, (InlayOffset, DiffPoint))>(&());
         cursor.seek(&point, Bias::Right, &());
         let overshoot = point.0 - cursor.start().0 .0;
         match cursor.item() {
             Some(Transform::Isomorphic(_)) => {
                 let buffer_point_start = cursor.start().1 .1;
-                let buffer_point_end = buffer_point_start + overshoot;
-                let buffer_offset_start = self.buffer.point_to_offset(buffer_point_start);
-                let buffer_offset_end = self.buffer.point_to_offset(buffer_point_end);
-                InlayOffset(cursor.start().1 .0 .0 + (buffer_offset_end - buffer_offset_start))
+                let buffer_point_end = buffer_point_start + DiffPoint(overshoot);
+                let buffer_offset_start =
+                    self.diff_map_snapshot.point_to_offset(buffer_point_start);
+                let buffer_offset_end = self.diff_map_snapshot.point_to_offset(buffer_point_end);
+                cursor.start().1 .0 + InlayOffset((buffer_offset_end - buffer_offset_start).0)
             }
             Some(Transform::Inlay(inlay)) => {
                 let overshoot = inlay.text.point_to_offset(overshoot);
-                InlayOffset(cursor.start().1 .0 .0 + overshoot)
+                cursor.start().1 .0 + InlayOffset(overshoot)
             }
             None => self.len(),
         }
     }
-    pub fn to_buffer_point(&self, point: InlayPoint) -> Point {
-        let mut cursor = self.transforms.cursor::<(InlayPoint, Point)>(&());
+
+    pub fn to_diff_point(&self, point: InlayPoint) -> DiffPoint {
+        let mut cursor = self.transforms.cursor::<(InlayPoint, DiffPoint)>(&());
         cursor.seek(&point, Bias::Right, &());
         match cursor.item() {
             Some(Transform::Isomorphic(_)) => {
                 let overshoot = point.0 - cursor.start().0 .0;
-                cursor.start().1 + overshoot
+                cursor.start().1 + DiffPoint(overshoot)
             }
             Some(Transform::Inlay(_)) => cursor.start().1,
-            None => self.buffer.max_point(),
+            None => self.diff_map_snapshot.max_point(),
         }
     }
-    pub fn to_buffer_offset(&self, offset: InlayOffset) -> usize {
-        let mut cursor = self.transforms.cursor::<(InlayOffset, usize)>(&());
+
+    pub fn to_diff_offset(&self, offset: InlayOffset) -> DiffOffset {
+        let mut cursor = self.transforms.cursor::<(InlayOffset, DiffOffset)>(&());
         cursor.seek(&offset, Bias::Right, &());
         match cursor.item() {
             Some(Transform::Isomorphic(_)) => {
                 let overshoot = offset - cursor.start().0;
-                cursor.start().1 + overshoot.0
+                cursor.start().1 + DiffOffset(overshoot.0)
             }
             Some(Transform::Inlay(_)) => cursor.start().1,
-            None => self.buffer.len(),
+            None => self.diff_map_snapshot.len(),
         }
     }
 
-    pub fn to_inlay_offset(&self, offset: usize) -> InlayOffset {
-        let mut cursor = self.transforms.cursor::<(usize, InlayOffset)>(&());
+    pub fn buffer(&self) -> &MultiBufferSnapshot {
+        &self.diff_map_snapshot.buffer
+    }
+
+    pub fn to_buffer_point(&self, point: InlayPoint) -> Point {
+        self.diff_map_snapshot
+            .to_multibuffer_point(self.to_diff_point(point))
+    }
+
+    pub fn to_buffer_offset(&self, offset: InlayOffset) -> usize {
+        self.diff_map_snapshot
+            .to_multibuffer_offset(self.to_diff_offset(offset))
+    }
+
+    pub fn to_inlay_offset(&self, offset: DiffOffset) -> InlayOffset {
+        let mut cursor = self.transforms.cursor::<(DiffOffset, InlayOffset)>(&());
         cursor.seek(&offset, Bias::Left, &());
         loop {
             match cursor.item() {
@@ -748,7 +767,7 @@ impl InlaySnapshot {
                         }
                         return cursor.end(&()).1;
                     } else {
-                        let overshoot = offset - cursor.start().0;
+                        let overshoot = offset.0 - cursor.start().0 .0;
                         return InlayOffset(cursor.start().1 .0 + overshoot);
                     }
                 }
@@ -765,8 +784,17 @@ impl InlaySnapshot {
             }
         }
     }
-    pub fn to_inlay_point(&self, point: Point) -> InlayPoint {
-        let mut cursor = self.transforms.cursor::<(Point, InlayPoint)>(&());
+
+    pub fn make_inlay_point(&self, multibuffer_point: Point) -> InlayPoint {
+        self.to_inlay_point(self.diff_map_snapshot.to_diff_point(multibuffer_point))
+    }
+
+    pub fn make_inlay_offset(&self, multibuffer_point: usize) -> InlayOffset {
+        self.to_inlay_offset(self.diff_map_snapshot.to_diff_offset(multibuffer_point))
+    }
+
+    pub fn to_inlay_point(&self, point: DiffPoint) -> InlayPoint {
+        let mut cursor = self.transforms.cursor::<(DiffPoint, InlayPoint)>(&());
         cursor.seek(&point, Bias::Left, &());
         loop {
             match cursor.item() {
@@ -782,7 +810,7 @@ impl InlaySnapshot {
                         return cursor.end(&()).1;
                     } else {
                         let overshoot = point - cursor.start().0;
-                        return InlayPoint(cursor.start().1 .0 + overshoot);
+                        return InlayPoint(cursor.start().1 .0 + overshoot.0);
                     }
                 }
                 Some(Transform::Inlay(inlay)) => {
@@ -800,7 +828,7 @@ impl InlaySnapshot {
     }
 
     pub fn clip_point(&self, mut point: InlayPoint, mut bias: Bias) -> InlayPoint {
-        let mut cursor = self.transforms.cursor::<(InlayPoint, Point)>(&());
+        let mut cursor = self.transforms.cursor::<(InlayPoint, DiffPoint)>(&());
         cursor.seek(&point, Bias::Left, &());
         loop {
             match cursor.item() {
@@ -836,10 +864,11 @@ impl InlaySnapshot {
                         }
                     } else {
                         let overshoot = point.0 - cursor.start().0 .0;
-                        let buffer_point = cursor.start().1 + overshoot;
-                        let clipped_buffer_point = self.buffer.clip_point(buffer_point, bias);
-                        let clipped_overshoot = clipped_buffer_point - cursor.start().1;
-                        let clipped_point = InlayPoint(cursor.start().0 .0 + clipped_overshoot);
+                        let diff_point = cursor.start().1 + DiffPoint(overshoot);
+                        let clipped_diff_point =
+                            self.diff_map_snapshot.clip_point(diff_point, bias);
+                        let clipped_overshoot = clipped_diff_point - cursor.start().1;
+                        let clipped_point = cursor.start().0 + InlayPoint(clipped_overshoot.0);
                         if clipped_point == point {
                             return clipped_point;
                         } else {
@@ -897,17 +926,19 @@ impl InlaySnapshot {
     pub fn text_summary_for_range(&self, range: Range<InlayOffset>) -> TextSummary {
         let mut summary = TextSummary::default();
 
-        let mut cursor = self.transforms.cursor::<(InlayOffset, usize)>(&());
+        let mut cursor = self.transforms.cursor::<(InlayOffset, DiffOffset)>(&());
         cursor.seek(&range.start, Bias::Right, &());
 
         let overshoot = range.start.0 - cursor.start().0 .0;
         match cursor.item() {
             Some(Transform::Isomorphic(_)) => {
                 let buffer_start = cursor.start().1;
-                let suffix_start = buffer_start + overshoot;
-                let suffix_end =
-                    buffer_start + (cmp::min(cursor.end(&()).0, range.end).0 - cursor.start().0 .0);
-                summary = self.buffer.text_summary_for_range(suffix_start..suffix_end);
+                let suffix_start = buffer_start + DiffOffset(overshoot);
+                let suffix_end = buffer_start
+                    + DiffOffset(cmp::min(cursor.end(&()).0, range.end).0 - cursor.start().0 .0);
+                summary = self
+                    .diff_map_snapshot
+                    .text_summary_for_range(suffix_start..suffix_end);
                 cursor.next(&());
             }
             Some(Transform::Inlay(inlay)) => {
@@ -928,10 +959,10 @@ impl InlaySnapshot {
             match cursor.item() {
                 Some(Transform::Isomorphic(_)) => {
                     let prefix_start = cursor.start().1;
-                    let prefix_end = prefix_start + overshoot;
+                    let prefix_end = prefix_start + DiffOffset(overshoot);
                     summary += self
-                        .buffer
-                        .text_summary_for_range::<TextSummary, _>(prefix_start..prefix_end);
+                        .diff_map_snapshot
+                        .text_summary_for_range(prefix_start..prefix_end);
                 }
                 Some(Transform::Inlay(inlay)) => {
                     let prefix_end = overshoot;
@@ -944,30 +975,30 @@ impl InlaySnapshot {
         summary
     }
 
-    pub fn buffer_rows(&self, row: u32) -> InlayBufferRows<'_> {
-        let mut cursor = self.transforms.cursor::<(InlayPoint, Point)>(&());
+    pub fn row_infos(&self, row: u32) -> InlayBufferRows<'_> {
+        let mut cursor = self.transforms.cursor::<(InlayPoint, DiffPoint)>(&());
         let inlay_point = InlayPoint::new(row, 0);
         cursor.seek(&inlay_point, Bias::Left, &());
 
-        let max_buffer_row = self.buffer.max_row();
-        let mut buffer_point = cursor.start().1;
-        let buffer_row = if row == 0 {
-            MultiBufferRow(0)
+        let max_point = self.diff_map_snapshot.max_point();
+        let mut diff_point = cursor.start().1;
+        let diff_row = if row == 0 {
+            0
         } else {
             match cursor.item() {
                 Some(Transform::Isomorphic(_)) => {
-                    buffer_point += inlay_point.0 - cursor.start().0 .0;
-                    MultiBufferRow(buffer_point.row)
+                    diff_point += DiffPoint(inlay_point.0 - cursor.start().0 .0);
+                    diff_point.row()
                 }
-                _ => cmp::min(MultiBufferRow(buffer_point.row + 1), max_buffer_row),
+                _ => cmp::min(diff_point.row() + 1, max_point.row()),
             }
         };
 
         InlayBufferRows {
             transforms: cursor,
             inlay_row: inlay_point.row(),
-            buffer_rows: self.buffer.buffer_rows(buffer_row),
-            max_buffer_row,
+            diff_rows: self.diff_map_snapshot.row_infos(diff_row),
+            max_point,
         }
     }
 
@@ -987,20 +1018,17 @@ impl InlaySnapshot {
         language_aware: bool,
         highlights: Highlights<'a>,
     ) -> InlayChunks<'a> {
-        let mut cursor = self.transforms.cursor::<(InlayOffset, usize)>(&());
+        let mut cursor = self.transforms.cursor::<(InlayOffset, DiffOffset)>(&());
         cursor.seek(&range.start, Bias::Right, &());
 
-        let buffer_range = self.to_buffer_offset(range.start)..self.to_buffer_offset(range.end);
-        let buffer_chunks = CustomHighlightsChunks::new(
-            buffer_range,
-            language_aware,
-            highlights.text_highlights,
-            &self.buffer,
-        );
+        let diff_range = self.to_diff_offset(range.start)..self.to_diff_offset(range.end);
+        let diff_map_chunks =
+            self.diff_map_snapshot
+                .chunks(diff_range, language_aware, highlights.text_highlights);
 
         InlayChunks {
             transforms: cursor,
-            buffer_chunks,
+            diff_map_chunks,
             inlay_chunks: None,
             inlay_chunk: None,
             buffer_chunk: None,
@@ -1022,7 +1050,10 @@ impl InlaySnapshot {
     fn check_invariants(&self) {
         #[cfg(any(debug_assertions, feature = "test-support"))]
         {
-            assert_eq!(self.transforms.summary().input, self.buffer.text_summary());
+            assert_eq!(
+                self.transforms.summary().input,
+                self.diff_map_snapshot.text_summary()
+            );
             let mut transforms = self.transforms.iter().peekable();
             while let Some(transform) = transforms.next() {
                 let transform_is_isomorphic = matches!(transform, Transform::Isomorphic(_));
@@ -1063,7 +1094,7 @@ fn push_isomorphic(sum_tree: &mut SumTree<Transform>, summary: TextSummary) {
 mod tests {
     use super::*;
     use crate::{
-        display_map::{InlayHighlights, TextHighlights},
+        display_map::{DiffMap, InlayHighlights, TextHighlights},
         hover_links::InlayHighlight,
         InlayId, MultiBuffer,
     };
@@ -1163,7 +1194,8 @@ mod tests {
     fn test_basic_inlays(cx: &mut AppContext) {
         let buffer = MultiBuffer::build_simple("abcdefghi", cx);
         let buffer_edits = buffer.update(cx, |buffer, _| buffer.subscribe());
-        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer.read(cx).snapshot(cx));
+        let (diff_map, diff_map_snapshot) = DiffMap::new(buffer.clone(), cx);
+        let (mut inlay_map, inlay_snapshot) = InlayMap::new(diff_map_snapshot.clone());
         assert_eq!(inlay_snapshot.text(), "abcdefghi");
         let mut next_inlay_id = 0;
 
@@ -1177,27 +1209,27 @@ mod tests {
         );
         assert_eq!(inlay_snapshot.text(), "abc|123|defghi");
         assert_eq!(
-            inlay_snapshot.to_inlay_point(Point::new(0, 0)),
+            inlay_snapshot.make_inlay_point(Point::new(0, 0)),
             InlayPoint::new(0, 0)
         );
         assert_eq!(
-            inlay_snapshot.to_inlay_point(Point::new(0, 1)),
+            inlay_snapshot.make_inlay_point(Point::new(0, 1)),
             InlayPoint::new(0, 1)
         );
         assert_eq!(
-            inlay_snapshot.to_inlay_point(Point::new(0, 2)),
+            inlay_snapshot.make_inlay_point(Point::new(0, 2)),
             InlayPoint::new(0, 2)
         );
         assert_eq!(
-            inlay_snapshot.to_inlay_point(Point::new(0, 3)),
+            inlay_snapshot.make_inlay_point(Point::new(0, 3)),
             InlayPoint::new(0, 3)
         );
         assert_eq!(
-            inlay_snapshot.to_inlay_point(Point::new(0, 4)),
+            inlay_snapshot.make_inlay_point(Point::new(0, 4)),
             InlayPoint::new(0, 9)
         );
         assert_eq!(
-            inlay_snapshot.to_inlay_point(Point::new(0, 5)),
+            inlay_snapshot.make_inlay_point(Point::new(0, 5)),
             InlayPoint::new(0, 10)
         );
         assert_eq!(
@@ -1229,18 +1261,26 @@ mod tests {
         buffer.update(cx, |buffer, cx| {
             buffer.edit([(2..3, "x"), (3..3, "y"), (4..4, "z")], None, cx)
         });
-        let (inlay_snapshot, _) = inlay_map.sync(
-            buffer.read(cx).snapshot(cx),
-            buffer_edits.consume().into_inner(),
-        );
+        let (diff_snapshot, diff_edits) = diff_map.update(cx, |diff_map, cx| {
+            diff_map.sync(
+                buffer.read(cx).snapshot(cx),
+                buffer_edits.consume().into_inner(),
+                cx,
+            )
+        });
+        let (inlay_snapshot, _) = inlay_map.sync(diff_snapshot, diff_edits);
         assert_eq!(inlay_snapshot.text(), "abxy|123|dzefghi");
 
         // An edit surrounding the inlay should invalidate it.
         buffer.update(cx, |buffer, cx| buffer.edit([(4..5, "D")], None, cx));
-        let (inlay_snapshot, _) = inlay_map.sync(
-            buffer.read(cx).snapshot(cx),
-            buffer_edits.consume().into_inner(),
-        );
+        let (diff_snapshot, diff_edits) = diff_map.update(cx, |diff_map, cx| {
+            diff_map.sync(
+                buffer.read(cx).snapshot(cx),
+                buffer_edits.consume().into_inner(),
+                cx,
+            )
+        });
+        let (inlay_snapshot, _) = inlay_map.sync(diff_snapshot, diff_edits);
         assert_eq!(inlay_snapshot.text(), "abxyDzefghi");
 
         let (inlay_snapshot, _) = inlay_map.splice(
@@ -1262,10 +1302,16 @@ mod tests {
 
         // Edits ending where the inlay starts should not move it if it has a left bias.
         buffer.update(cx, |buffer, cx| buffer.edit([(3..3, "JKL")], None, cx));
-        let (inlay_snapshot, _) = inlay_map.sync(
-            buffer.read(cx).snapshot(cx),
-            buffer_edits.consume().into_inner(),
-        );
+
+        let (diff_snapshot, diff_edits) = diff_map.update(cx, |diff_map, cx| {
+            diff_map.sync(
+                buffer.read(cx).snapshot(cx),
+                buffer_edits.consume().into_inner(),
+                cx,
+            )
+        });
+
+        let (inlay_snapshot, _) = inlay_map.sync(diff_snapshot, diff_edits);
         assert_eq!(inlay_snapshot.text(), "abx|123|JKL|456|yDzefghi");
 
         assert_eq!(
@@ -1450,7 +1496,8 @@ mod tests {
     #[gpui::test]
     fn test_inlay_buffer_rows(cx: &mut AppContext) {
         let buffer = MultiBuffer::build_simple("abc\ndef\nghi", cx);
-        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer.read(cx).snapshot(cx));
+        let (_diff_map, diff_map_snapshot) = DiffMap::new(buffer.clone(), cx);
+        let (mut inlay_map, inlay_snapshot) = InlayMap::new(diff_map_snapshot);
         assert_eq!(inlay_snapshot.text(), "abc\ndef\nghi");
         let mut next_inlay_id = 0;
 
@@ -1476,7 +1523,10 @@ mod tests {
         );
         assert_eq!(inlay_snapshot.text(), "|123|\nabc\n|456|def\n|567|\n\nghi");
         assert_eq!(
-            inlay_snapshot.buffer_rows(0).collect::<Vec<_>>(),
+            inlay_snapshot
+                .row_infos(0)
+                .map(|r| r.buffer_row)
+                .collect::<Vec<_>>(),
             vec![Some(0), None, Some(1), None, None, Some(2)]
         );
     }
@@ -1501,7 +1551,8 @@ mod tests {
         let mut buffer_snapshot = buffer.read(cx).snapshot(cx);
         let mut next_inlay_id = 0;
         log::info!("buffer text: {:?}", buffer_snapshot.text());
-        let (mut inlay_map, mut inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (diff_map, diff_map_snapshot) = DiffMap::new(buffer.clone(), cx);
+        let (mut inlay_map, mut inlay_snapshot) = InlayMap::new(diff_map_snapshot.clone());
         for _ in 0..operations {
             let mut inlay_edits = Patch::default();
 
@@ -1524,8 +1575,12 @@ mod tests {
                 }),
             };
 
+            let (new_diff_snapshot, new_diff_edits) = diff_map.update(cx, |diff_map, cx| {
+                diff_map.sync(buffer.read(cx).snapshot(cx), buffer_edits, cx)
+            });
+
             let (new_inlay_snapshot, new_inlay_edits) =
-                inlay_map.sync(buffer_snapshot.clone(), buffer_edits);
+                inlay_map.sync(new_diff_snapshot, new_diff_edits);
             inlay_snapshot = new_inlay_snapshot;
             inlay_edits = inlay_edits.compose(new_inlay_edits);
 
@@ -1547,7 +1602,7 @@ mod tests {
             }
             assert_eq!(inlay_snapshot.text(), expected_text.to_string());
 
-            let expected_buffer_rows = inlay_snapshot.buffer_rows(0).collect::<Vec<_>>();
+            let expected_buffer_rows = inlay_snapshot.row_infos(0).collect::<Vec<_>>();
             assert_eq!(
                 expected_buffer_rows.len() as u32,
                 expected_text.max_point().row + 1
@@ -1555,7 +1610,7 @@ mod tests {
             for row_start in 0..expected_buffer_rows.len() {
                 assert_eq!(
                     inlay_snapshot
-                        .buffer_rows(row_start as u32)
+                        .row_infos(row_start as u32)
                         .collect::<Vec<_>>(),
                     &expected_buffer_rows[row_start..],
                     "incorrect buffer rows starting at {}",
@@ -1673,14 +1728,14 @@ mod tests {
             assert_eq!(expected_text.len(), inlay_snapshot.len().0);
 
             let mut buffer_point = Point::default();
-            let mut inlay_point = inlay_snapshot.to_inlay_point(buffer_point);
+            let mut inlay_point = inlay_snapshot.make_inlay_point(buffer_point);
             let mut buffer_chars = buffer_snapshot.chars_at(0);
             loop {
                 // Ensure conversion from buffer coordinates to inlay coordinates
                 // is consistent.
                 let buffer_offset = buffer_snapshot.point_to_offset(buffer_point);
                 assert_eq!(
-                    inlay_snapshot.to_point(inlay_snapshot.to_inlay_offset(buffer_offset)),
+                    inlay_snapshot.to_point(inlay_snapshot.make_inlay_offset(buffer_offset)),
                     inlay_point
                 );
 
@@ -1707,7 +1762,7 @@ mod tests {
                     }
 
                     // Ensure that moving forward in the buffer always moves the inlay point forward as well.
-                    let new_inlay_point = inlay_snapshot.to_inlay_point(buffer_point);
+                    let new_inlay_point = inlay_snapshot.make_inlay_point(buffer_point);
                     assert!(new_inlay_point > inlay_point);
                     inlay_point = new_inlay_point;
                 } else {
@@ -1767,7 +1822,7 @@ mod tests {
                     // Ensure the clipped points are at valid buffer locations.
                     assert_eq!(
                         inlay_snapshot
-                            .to_inlay_point(inlay_snapshot.to_buffer_point(clipped_left_point)),
+                            .to_inlay_point(inlay_snapshot.to_diff_point(clipped_left_point)),
                         clipped_left_point,
                         "to_buffer_point({:?}) = {:?}",
                         clipped_left_point,
@@ -1775,7 +1830,7 @@ mod tests {
                     );
                     assert_eq!(
                         inlay_snapshot
-                            .to_inlay_point(inlay_snapshot.to_buffer_point(clipped_right_point)),
+                            .to_inlay_point(inlay_snapshot.to_diff_point(clipped_right_point)),
                         clipped_right_point,
                         "to_buffer_point({:?}) = {:?}",
                         clipped_right_point,

crates/editor/src/display_map/tab_map.rs

@@ -164,7 +164,7 @@ pub struct TabSnapshot {
 
 impl TabSnapshot {
     pub fn buffer_snapshot(&self) -> &MultiBufferSnapshot {
-        &self.fold_snapshot.inlay_snapshot.buffer
+        self.fold_snapshot.inlay_snapshot.buffer()
     }
 
     pub fn line_len(&self, row: u32) -> u32 {
@@ -272,8 +272,8 @@ impl TabSnapshot {
         }
     }
 
-    pub fn buffer_rows(&self, row: u32) -> fold_map::FoldBufferRows<'_> {
-        self.fold_snapshot.buffer_rows(row)
+    pub fn rows(&self, row: u32) -> fold_map::FoldRows<'_> {
+        self.fold_snapshot.row_infos(row)
     }
 
     #[cfg(test)]
@@ -317,8 +317,7 @@ impl TabSnapshot {
     }
 
     pub fn make_tab_point(&self, point: Point, bias: Bias) -> TabPoint {
-        let inlay_point = self.fold_snapshot.inlay_snapshot.to_inlay_point(point);
-        let fold_point = self.fold_snapshot.to_fold_point(inlay_point, bias);
+        let fold_point = self.fold_snapshot.make_fold_point(point, bias);
         self.to_tab_point(fold_point)
     }
 
@@ -602,7 +601,7 @@ impl<'a> Iterator for TabChunks<'a> {
 mod tests {
     use super::*;
     use crate::{
-        display_map::{fold_map::FoldMap, inlay_map::InlayMap},
+        display_map::{diff_map::DiffMap, fold_map::FoldMap, inlay_map::InlayMap},
         MultiBuffer,
     };
     use rand::{prelude::StdRng, Rng};
@@ -610,8 +609,8 @@ mod tests {
     #[gpui::test]
     fn test_expand_tabs(cx: &mut gpui::AppContext) {
         let buffer = MultiBuffer::build_simple("", cx);
-        let buffer_snapshot = buffer.read(cx).snapshot(cx);
-        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (_, diff_snapshot) = DiffMap::new(buffer, cx);
+        let (_, inlay_snapshot) = InlayMap::new(diff_snapshot.clone());
         let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
         let (_, tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
 
@@ -627,8 +626,8 @@ mod tests {
         let output = "A   BC  DEF G   HI J K L M";
 
         let buffer = MultiBuffer::build_simple(input, cx);
-        let buffer_snapshot = buffer.read(cx).snapshot(cx);
-        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (_, diff_snapshot) = DiffMap::new(buffer, cx);
+        let (_, inlay_snapshot) = InlayMap::new(diff_snapshot.clone());
         let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
         let (_, mut tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
 
@@ -674,8 +673,8 @@ mod tests {
         let input = "abcdefg⋯hij";
 
         let buffer = MultiBuffer::build_simple(input, cx);
-        let buffer_snapshot = buffer.read(cx).snapshot(cx);
-        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (_, diff_snapshot) = DiffMap::new(buffer.clone(), cx);
+        let (_, inlay_snapshot) = InlayMap::new(diff_snapshot.clone());
         let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
         let (_, mut tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
 
@@ -688,8 +687,8 @@ mod tests {
         let input = "\t \thello";
 
         let buffer = MultiBuffer::build_simple(input, cx);
-        let buffer_snapshot = buffer.read(cx).snapshot(cx);
-        let (_, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (_, diff_snapshot) = DiffMap::new(buffer.clone(), cx);
+        let (_, inlay_snapshot) = InlayMap::new(diff_snapshot);
         let (_, fold_snapshot) = FoldMap::new(inlay_snapshot);
         let (_, tab_snapshot) = TabMap::new(fold_snapshot, 4.try_into().unwrap());
 
@@ -749,8 +748,11 @@ mod tests {
         let buffer_snapshot = buffer.read(cx).snapshot(cx);
         log::info!("Buffer text: {:?}", buffer_snapshot.text());
 
-        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
-        log::info!("InlayMap text: {:?}", inlay_snapshot.text());
+        let (_, diff_snapshot) = DiffMap::new(buffer.clone(), cx);
+
+        let (mut inlay_map, inlay_snapshot) = InlayMap::new(diff_snapshot.clone());
+
+        log::info!("DiffMap text: {:?}", diff_snapshot.text());
         let (mut fold_map, _) = FoldMap::new(inlay_snapshot.clone());
         fold_map.randomly_mutate(&mut rng);
         let (fold_snapshot, _) = fold_map.read(inlay_snapshot, vec![]);

crates/editor/src/display_map/wrap_map.rs

@@ -1,5 +1,7 @@
+use crate::RowInfo;
+
 use super::{
-    fold_map::FoldBufferRows,
+    fold_map::FoldRows,
     tab_map::{self, TabEdit, TabPoint, TabSnapshot},
     Highlights,
 };
@@ -60,16 +62,16 @@ pub struct WrapChunks<'a> {
 }
 
 #[derive(Clone)]
-pub struct WrapBufferRows<'a> {
-    input_buffer_rows: FoldBufferRows<'a>,
-    input_buffer_row: Option<u32>,
+pub struct WrapRows<'a> {
+    input_buffer_rows: FoldRows<'a>,
+    input_buffer_row: RowInfo,
     output_row: u32,
     soft_wrapped: bool,
     max_output_row: u32,
     transforms: Cursor<'a, Transform, (WrapPoint, TabPoint)>,
 }
 
-impl<'a> WrapBufferRows<'a> {
+impl<'a> WrapRows<'a> {
     pub(crate) fn seek(&mut self, start_row: u32) {
         self.transforms
             .seek(&WrapPoint::new(start_row, 0), Bias::Left, &());
@@ -717,7 +719,7 @@ impl WrapSnapshot {
         self.transforms.summary().output.longest_row
     }
 
-    pub fn buffer_rows(&self, start_row: u32) -> WrapBufferRows {
+    pub fn row_infos(&self, start_row: u32) -> WrapRows {
         let mut transforms = self.transforms.cursor::<(WrapPoint, TabPoint)>(&());
         transforms.seek(&WrapPoint::new(start_row, 0), Bias::Left, &());
         let mut input_row = transforms.start().1.row();
@@ -725,9 +727,9 @@ impl WrapSnapshot {
             input_row += start_row - transforms.start().0.row();
         }
         let soft_wrapped = transforms.item().map_or(false, |t| !t.is_isomorphic());
-        let mut input_buffer_rows = self.tab_snapshot.buffer_rows(input_row);
+        let mut input_buffer_rows = self.tab_snapshot.rows(input_row);
         let input_buffer_row = input_buffer_rows.next().unwrap();
-        WrapBufferRows {
+        WrapRows {
             transforms,
             input_buffer_row,
             input_buffer_rows,
@@ -847,7 +849,7 @@ impl WrapSnapshot {
             }
 
             let text = language::Rope::from(self.text().as_str());
-            let mut input_buffer_rows = self.tab_snapshot.buffer_rows(0);
+            let mut input_buffer_rows = self.tab_snapshot.rows(0);
             let mut expected_buffer_rows = Vec::new();
             let mut prev_tab_row = 0;
             for display_row in 0..=self.max_point().row() {
@@ -855,7 +857,7 @@ impl WrapSnapshot {
                 if tab_point.row() == prev_tab_row && display_row != 0 {
                     expected_buffer_rows.push(None);
                 } else {
-                    expected_buffer_rows.push(input_buffer_rows.next().unwrap());
+                    expected_buffer_rows.push(input_buffer_rows.next().unwrap().buffer_row);
                 }
 
                 prev_tab_row = tab_point.row();
@@ -864,7 +866,8 @@ impl WrapSnapshot {
 
             for start_display_row in 0..expected_buffer_rows.len() {
                 assert_eq!(
-                    self.buffer_rows(start_display_row as u32)
+                    self.row_infos(start_display_row as u32)
+                        .map(|row_info| row_info.buffer_row)
                         .collect::<Vec<_>>(),
                     &expected_buffer_rows[start_display_row..],
                     "invalid buffer_rows({}..)",
@@ -958,8 +961,8 @@ impl<'a> Iterator for WrapChunks<'a> {
     }
 }
 
-impl<'a> Iterator for WrapBufferRows<'a> {
-    type Item = Option<u32>;
+impl<'a> Iterator for WrapRows<'a> {
+    type Item = RowInfo;
 
     fn next(&mut self) -> Option<Self::Item> {
         if self.output_row > self.max_output_row {
@@ -979,7 +982,11 @@ impl<'a> Iterator for WrapBufferRows<'a> {
             self.soft_wrapped = true;
         }
 
-        Some(if soft_wrapped { None } else { buffer_row })
+        Some(if soft_wrapped {
+            RowInfo::default()
+        } else {
+            buffer_row
+        })
     }
 }
 
@@ -1161,7 +1168,7 @@ fn consolidate_wrap_edits(edits: Vec<WrapEdit>) -> Vec<WrapEdit> {
 mod tests {
     use super::*;
     use crate::{
-        display_map::{fold_map::FoldMap, inlay_map::InlayMap, tab_map::TabMap},
+        display_map::{diff_map::DiffMap, fold_map::FoldMap, inlay_map::InlayMap, tab_map::TabMap},
         MultiBuffer,
     };
     use gpui::{font, px, test::observe};
@@ -1209,9 +1216,11 @@ mod tests {
         });
         let mut buffer_snapshot = buffer.read_with(cx, |buffer, cx| buffer.snapshot(cx));
         log::info!("Buffer text: {:?}", buffer_snapshot.text());
-        let (mut inlay_map, inlay_snapshot) = InlayMap::new(buffer_snapshot.clone());
+        let (diff_map, diff_snapshot) = cx.update(|cx| DiffMap::new(buffer.clone(), cx));
+        log::info!("DiffMap text: {:?}", diff_snapshot.text());
+        let (mut inlay_map, inlay_snapshot) = InlayMap::new(diff_snapshot);
         log::info!("InlayMap text: {:?}", inlay_snapshot.text());
-        let (mut fold_map, fold_snapshot) = FoldMap::new(inlay_snapshot.clone());
+        let (mut fold_map, fold_snapshot) = FoldMap::new(inlay_snapshot);
         log::info!("FoldMap text: {:?}", fold_snapshot.text());
         let (mut tab_map, _) = TabMap::new(fold_snapshot.clone(), tab_size);
         let tabs_snapshot = tab_map.set_max_expansion_column(32);
@@ -1293,8 +1302,10 @@ mod tests {
             }
 
             log::info!("Buffer text: {:?}", buffer_snapshot.text());
-            let (inlay_snapshot, inlay_edits) =
-                inlay_map.sync(buffer_snapshot.clone(), buffer_edits);
+            let (diff_snapshot, diff_edits) = diff_map.update(cx, |diff_map, cx| {
+                diff_map.sync(buffer_snapshot.clone(), buffer_edits, cx)
+            });
+            let (inlay_snapshot, inlay_edits) = inlay_map.sync(diff_snapshot, diff_edits);
             log::info!("InlayMap text: {:?}", inlay_snapshot.text());
             let (fold_snapshot, fold_edits) = fold_map.read(inlay_snapshot, inlay_edits);
             log::info!("FoldMap text: {:?}", fold_snapshot.text());

crates/editor/src/editor.rs

@@ -89,7 +89,7 @@ use gpui::{
 use highlight_matching_bracket::refresh_matching_bracket_highlights;
 use hover_popover::{hide_hover, HoverState};
 pub(crate) use hunk_diff::HoveredHunk;
-use hunk_diff::{diff_hunk_to_display, DiffMap, DiffMapSnapshot};
+use hunk_diff::{diff_hunk_to_display, DiffMap};
 use indent_guides::ActiveIndentGuidesState;
 use inlay_hint_cache::{InlayHintCache, InlaySplice, InvalidationStrategy};
 pub use inline_completion::Direction;
@@ -725,7 +725,6 @@ pub struct EditorSnapshot {
     git_blame_gutter_max_author_length: Option<usize>,
     pub display_snapshot: DisplaySnapshot,
     pub placeholder_text: Option<Arc<str>>,
-    diff_map: DiffMapSnapshot,
     is_focused: bool,
     scroll_anchor: ScrollAnchor,
     ongoing_scroll: OngoingScroll,
@@ -1205,7 +1204,12 @@ impl Editor {
 
         let mut code_action_providers = Vec::new();
         if let Some(project) = project.clone() {
-            get_unstaged_changes_for_buffers(&project, buffer.read(cx).all_buffers(), cx);
+            get_unstaged_changes_for_buffers(
+                &project,
+                buffer.read(cx).all_buffers(),
+                display_map.clone(),
+                cx,
+            );
             code_action_providers.push(Rc::new(project) as Rc<_>);
         }
 
@@ -1568,7 +1572,6 @@ impl Editor {
             scroll_anchor: self.scroll_manager.anchor(),
             ongoing_scroll: self.scroll_manager.ongoing_scroll(),
             placeholder_text: self.placeholder_text.clone(),
-            diff_map: self.diff_map.snapshot(),
             is_focused: self.focus_handle.is_focused(cx),
             current_line_highlight: self
                 .current_line_highlight
@@ -5082,7 +5085,7 @@ impl Editor {
             }))
     }
 
-    #[cfg(feature = "test-support")]
+    #[cfg(any(test, feature = "test-support"))]
     pub fn context_menu_visible(&self) -> bool {
         self.context_menu
             .borrow()
@@ -5918,10 +5921,9 @@ impl Editor {
     pub fn revert_file(&mut self, _: &RevertFile, cx: &mut ViewContext<Self>) {
         let mut revert_changes = HashMap::default();
         let snapshot = self.snapshot(cx);
-        for hunk in hunks_for_ranges(
-            Some(Point::zero()..snapshot.buffer_snapshot.max_point()).into_iter(),
-            &snapshot,
-        ) {
+        for hunk in snapshot
+            .hunks_for_ranges(Some(Point::zero()..snapshot.buffer_snapshot.max_point()).into_iter())
+        {
             self.prepare_revert_change(&mut revert_changes, &hunk, cx);
         }
         if !revert_changes.is_empty() {
@@ -5939,7 +5941,12 @@ impl Editor {
     }
 
     pub fn revert_selected_hunks(&mut self, _: &RevertSelectedHunks, cx: &mut ViewContext<Self>) {
-        let revert_changes = self.gather_revert_changes(&self.selections.all(cx), cx);
+        let selections = self.selections.all(cx).into_iter().map(|s| s.range());
+        let mut revert_changes = HashMap::default();
+        let snapshot = self.snapshot(cx);
+        for hunk in &snapshot.hunks_for_ranges(selections) {
+            self.prepare_revert_change(&mut revert_changes, &hunk, cx);
+        }
         if !revert_changes.is_empty() {
             self.transact(cx, |editor, cx| {
                 editor.revert(revert_changes, cx);
@@ -5976,28 +5983,18 @@ impl Editor {
         }
     }
 
-    fn gather_revert_changes(
-        &mut self,
-        selections: &[Selection<Point>],
-        cx: &mut ViewContext<'_, Editor>,
-    ) -> HashMap<BufferId, Vec<(Range<text::Anchor>, Rope)>> {
-        let mut revert_changes = HashMap::default();
-        let snapshot = self.snapshot(cx);
-        for hunk in hunks_for_selections(&snapshot, selections) {
-            self.prepare_revert_change(&mut revert_changes, &hunk, cx);
-        }
-        revert_changes
-    }
-
     pub fn prepare_revert_change(
         &mut self,
         revert_changes: &mut HashMap<BufferId, Vec<(Range<text::Anchor>, Rope)>>,
         hunk: &MultiBufferDiffHunk,
-        cx: &AppContext,
+        cx: &mut WindowContext,
     ) -> Option<()> {
+        let change_set = self
+            .display_map
+            .read(cx)
+            .diff_base_for(hunk.buffer_id, cx)?;
         let buffer = self.buffer.read(cx).buffer(hunk.buffer_id)?;
         let buffer = buffer.read(cx);
-        let change_set = &self.diff_map.diff_bases.get(&hunk.buffer_id)?.change_set;
         let original_text = change_set
             .read(cx)
             .base_text
@@ -9213,9 +9210,8 @@ impl Editor {
                 snapshot,
                 position,
                 ix > 0,
-                snapshot.diff_map.diff_hunks_in_range(
+                snapshot.diff_hunks_in_range(
                     position + Point::new(1, 0)..snapshot.buffer_snapshot.max_point(),
-                    &snapshot.buffer_snapshot,
                 ),
                 cx,
             ) {
@@ -9245,9 +9241,7 @@ impl Editor {
                 snapshot,
                 position,
                 ix > 0,
-                snapshot
-                    .diff_map
-                    .diff_hunks_in_range_rev(Point::zero()..position, &snapshot.buffer_snapshot),
+                snapshot.diff_hunks_in_range_rev(Point::zero()..position),
                 cx,
             ) {
                 return Some(hunk);
@@ -10930,6 +10924,29 @@ impl Editor {
         self.display_map.read(cx).fold_placeholder.clone()
     }
 
+    pub fn set_expand_all_diff_hunks(&mut self, cx: &mut AppContext) {
+        self.display_map.update(cx, |display_map, cx| {
+            display_map.set_all_hunks_expanded(cx);
+        });
+    }
+
+    pub fn expand_all_diff_hunks(&mut self, _: &ExpandAllHunkDiffs, cx: &mut ViewContext<Self>) {
+        self.display_map.update(cx, |display_map, cx| {
+            display_map.expand_diff_hunks(vec![Anchor::min()..Anchor::max()], cx)
+        });
+    }
+
+    pub fn toggle_hunk_diff(&mut self, _: &ToggleHunkDiff, cx: &mut ViewContext<Self>) {
+        let ranges: Vec<_> = self.selections.disjoint.iter().map(|s| s.range()).collect();
+        self.display_map.update(cx, |display_map, cx| {
+            if display_map.has_expanded_diff_hunks_in_ranges(&ranges, cx) {
+                display_map.collapse_diff_hunks(ranges, cx)
+            } else {
+                display_map.expand_diff_hunks(ranges, cx)
+            }
+        })
+    }
+
     pub fn set_gutter_hovered(&mut self, hovered: bool, cx: &mut ViewContext<Self>) {
         if hovered != self.gutter_hovered {
             self.gutter_hovered = hovered;
@@ -12233,7 +12250,12 @@ impl Editor {
                 let buffer_id = buffer.read(cx).remote_id();
                 if !self.diff_map.diff_bases.contains_key(&buffer_id) {
                     if let Some(project) = &self.project {
-                        get_unstaged_changes_for_buffers(project, [buffer.clone()], cx);
+                        get_unstaged_changes_for_buffers(
+                            project,
+                            [buffer.clone()],
+                            self.display_map.clone(),
+                            cx,
+                        );
                     }
                 }
                 cx.emit(EditorEvent::ExcerptsAdded {
@@ -12937,7 +12959,8 @@ impl Editor {
 fn get_unstaged_changes_for_buffers(
     project: &Model<Project>,
     buffers: impl IntoIterator<Item = Model<Buffer>>,
-    cx: &mut ViewContext<Editor>,
+    display_map: Model<DisplayMap>,
+    cx: &mut AppContext,
 ) {
     let mut tasks = Vec::new();
     project.update(cx, |project, cx| {
@@ -12945,16 +12968,17 @@ fn get_unstaged_changes_for_buffers(
             tasks.push(project.open_unstaged_changes(buffer.clone(), cx))
         }
     });
-    cx.spawn(|this, mut cx| async move {
+    cx.spawn(|mut cx| async move {
         let change_sets = futures::future::join_all(tasks).await;
-        this.update(&mut cx, |this, cx| {
-            for change_set in change_sets {
-                if let Some(change_set) = change_set.log_err() {
-                    this.diff_map.add_change_set(change_set, cx);
+        display_map
+            .update(&mut cx, |display_map, cx| {
+                for change_set in change_sets {
+                    if let Some(change_set) = change_set.log_err() {
+                        display_map.add_change_set(change_set, cx);
+                    }
                 }
-            }
-        })
-        .ok();
+            })
+            .ok();
     })
     .detach();
 }
@@ -13242,56 +13266,6 @@ fn test_wrap_with_prefix() {
     );
 }
 
-fn hunks_for_selections(
-    snapshot: &EditorSnapshot,
-    selections: &[Selection<Point>],
-) -> Vec<MultiBufferDiffHunk> {
-    hunks_for_ranges(
-        selections.iter().map(|selection| selection.range()),
-        snapshot,
-    )
-}
-
-pub fn hunks_for_ranges(
-    ranges: impl Iterator<Item = Range<Point>>,
-    snapshot: &EditorSnapshot,
-) -> Vec<MultiBufferDiffHunk> {
-    let mut hunks = Vec::new();
-    let mut processed_buffer_rows: HashMap<BufferId, HashSet<Range<text::Anchor>>> =
-        HashMap::default();
-    for query_range in ranges {
-        let query_rows =
-            MultiBufferRow(query_range.start.row)..MultiBufferRow(query_range.end.row + 1);
-        for hunk in snapshot.diff_map.diff_hunks_in_range(
-            Point::new(query_rows.start.0, 0)..Point::new(query_rows.end.0, 0),
-            &snapshot.buffer_snapshot,
-        ) {
-            // Deleted hunk is an empty row range, no caret can be placed there and Zed allows to revert it
-            // when the caret is just above or just below the deleted hunk.
-            let allow_adjacent = hunk_status(&hunk) == DiffHunkStatus::Removed;
-            let related_to_selection = if allow_adjacent {
-                hunk.row_range.overlaps(&query_rows)
-                    || hunk.row_range.start == query_rows.end
-                    || hunk.row_range.end == query_rows.start
-            } else {
-                hunk.row_range.overlaps(&query_rows)
-            };
-            if related_to_selection {
-                if !processed_buffer_rows
-                    .entry(hunk.buffer_id)
-                    .or_default()
-                    .insert(hunk.buffer_range.start..hunk.buffer_range.end)
-                {
-                    continue;
-                }
-                hunks.push(hunk);
-            }
-        }
-    }
-
-    hunks
-}
-
 pub trait CollaborationHub {
     fn collaborators<'a>(&self, cx: &'a AppContext) -> &'a HashMap<PeerId, Collaborator>;
     fn user_participant_indices<'a>(
@@ -13840,6 +13814,45 @@ impl EditorSnapshot {
             })
     }
 
+    pub fn hunks_for_ranges(
+        &self,
+        ranges: impl Iterator<Item = Range<Point>>,
+    ) -> Vec<MultiBufferDiffHunk> {
+        let mut hunks = Vec::new();
+        let mut processed_buffer_rows: HashMap<BufferId, HashSet<Range<text::Anchor>>> =
+            HashMap::default();
+        for query_range in ranges {
+            let query_rows =
+                MultiBufferRow(query_range.start.row)..MultiBufferRow(query_range.end.row + 1);
+            for hunk in self.diff_snapshot().diff_hunks_in_range(
+                Point::new(query_rows.start.0, 0)..Point::new(query_rows.end.0, 0),
+            ) {
+                // Deleted hunk is an empty row range, no caret can be placed there and Zed allows to revert it
+                // when the caret is just above or just below the deleted hunk.
+                let allow_adjacent = hunk_status(&hunk) == DiffHunkStatus::Removed;
+                let related_to_selection = if allow_adjacent {
+                    hunk.row_range.overlaps(&query_rows)
+                        || hunk.row_range.start == query_rows.end
+                        || hunk.row_range.end == query_rows.start
+                } else {
+                    hunk.row_range.overlaps(&query_rows)
+                };
+                if related_to_selection {
+                    if !processed_buffer_rows
+                        .entry(hunk.buffer_id)
+                        .or_default()
+                        .insert(hunk.buffer_range.start..hunk.buffer_range.end)
+                    {
+                        continue;
+                    }
+                    hunks.push(hunk);
+                }
+            }
+        }
+
+        hunks
+    }
+
     pub fn language_at<T: ToOffset>(&self, position: T) -> Option<&Arc<Language>> {
         self.display_snapshot.buffer_snapshot.language_at(position)
     }

crates/editor/src/editor_tests.rs

@@ -3359,8 +3359,7 @@ async fn test_custom_newlines_cause_no_false_positive_diffs(
         let snapshot = editor.snapshot(cx);
         assert_eq!(
             snapshot
-                .diff_map
-                .diff_hunks_in_range(0..snapshot.buffer_snapshot.len(), &snapshot.buffer_snapshot)
+                .diff_hunks_in_range(0..snapshot.buffer_snapshot.len())
                 .collect::<Vec<_>>(),
             Vec::new(),
             "Should not have any diffs for files with custom newlines"
@@ -11655,7 +11654,9 @@ async fn test_multibuffer_reverts(cx: &mut gpui::TestAppContext) {
                     cx,
                 )
             });
-            editor.diff_map.add_change_set(change_set, cx)
+            editor.display_map.update(cx, |display_map, cx| {
+                display_map.add_change_set(change_set, cx)
+            });
         }
     });
     cx.executor().run_until_parked();
@@ -12073,12 +12074,34 @@ async fn test_toggle_hunk_diff(executor: BackgroundExecutor, cx: &mut gpui::Test
     );
 
     cx.update_editor(|editor, cx| {
-        for _ in 0..3 {
+        for _ in 0..2 {
             editor.go_to_next_hunk(&GoToHunk, cx);
             editor.toggle_hunk_diff(&ToggleHunkDiff, cx);
         }
     });
     executor.run_until_parked();
+    cx.assert_state_with_diff(
+        r#"
+        - use some::mod;
+        + ˇuse some::modified;
+
+
+          fn main() {
+        -     println!("hello");
+        +     println!("hello there");
+
+        +     println!("around the");
+              println!("world");
+          }
+        "#
+        .unindent(),
+    );
+
+    cx.update_editor(|editor, cx| {
+        editor.go_to_next_hunk(&GoToHunk, cx);
+        editor.toggle_hunk_diff(&ToggleHunkDiff, cx);
+    });
+    executor.run_until_parked();
     cx.assert_state_with_diff(
         r#"
         - use some::mod;
@@ -12164,7 +12187,7 @@ async fn test_diff_base_change_with_expanded_diff_hunks(
     executor.run_until_parked();
 
     cx.update_editor(|editor, cx| {
-        editor.expand_all_hunk_diffs(&ExpandAllHunkDiffs, cx);
+        editor.expand_all_diff_hunks(&ExpandAllHunkDiffs, cx);
     });
     executor.run_until_parked();
     cx.assert_state_with_diff(
@@ -12209,7 +12232,7 @@ async fn test_diff_base_change_with_expanded_diff_hunks(
     );
 
     cx.update_editor(|editor, cx| {
-        editor.expand_all_hunk_diffs(&ExpandAllHunkDiffs, cx);
+        editor.expand_all_diff_hunks(&ExpandAllHunkDiffs, cx);
     });
     executor.run_until_parked();
     cx.assert_state_with_diff(
@@ -12292,7 +12315,7 @@ async fn test_fold_unfold_diff_hunk(executor: BackgroundExecutor, cx: &mut gpui:
     executor.run_until_parked();
 
     cx.update_editor(|editor, cx| {
-        editor.expand_all_hunk_diffs(&ExpandAllHunkDiffs, cx);
+        editor.expand_all_diff_hunks(&ExpandAllHunkDiffs, cx);
     });
     executor.run_until_parked();
 
@@ -12485,7 +12508,9 @@ async fn test_toggle_diff_expand_in_multi_buffer(cx: &mut gpui::TestAppContext)
                         cx,
                     )
                 });
-                editor.diff_map.add_change_set(change_set, cx)
+                editor.display_map.update(cx, |display_map, cx| {
+                    display_map.add_change_set(change_set, cx)
+                });
             }
         })
         .unwrap();
@@ -12595,14 +12620,16 @@ async fn test_expand_diff_hunk_at_excerpt_boundary(cx: &mut gpui::TestAppContext
             let buffer = buffer.read(cx).text_snapshot();
             let change_set = cx
                 .new_model(|cx| BufferChangeSet::new_with_base_text(base.to_string(), buffer, cx));
-            editor.diff_map.add_change_set(change_set, cx)
+            editor.display_map.update(cx, |display_map, cx| {
+                display_map.add_change_set(change_set, cx)
+            })
         })
         .unwrap();
 
     let mut cx = EditorTestContext::for_editor(editor, cx).await;
     cx.run_until_parked();
 
-    cx.update_editor(|editor, cx| editor.expand_all_hunk_diffs(&Default::default(), cx));
+    cx.update_editor(|editor, cx| editor.expand_all_diff_hunks(&Default::default(), cx));
     cx.executor().run_until_parked();
 
     cx.assert_state_with_diff(
@@ -12666,7 +12693,7 @@ async fn test_edits_around_expanded_insertion_hunks(
     executor.run_until_parked();
 
     cx.update_editor(|editor, cx| {
-        editor.expand_all_hunk_diffs(&ExpandAllHunkDiffs, cx);
+        editor.expand_all_diff_hunks(&ExpandAllHunkDiffs, cx);
     });
     executor.run_until_parked();
 
@@ -12685,7 +12712,7 @@ async fn test_edits_around_expanded_insertion_hunks(
 
             println!("world");
         }
-        "#
+      "#
         .unindent(),
     );
 
@@ -12708,7 +12735,7 @@ async fn test_edits_around_expanded_insertion_hunks(
 
             println!("world");
         }
-        "#
+      "#
         .unindent(),
     );
 
@@ -12732,7 +12759,7 @@ async fn test_edits_around_expanded_insertion_hunks(
 
             println!("world");
         }
-        "#
+      "#
         .unindent(),
     );
 
@@ -12757,7 +12784,7 @@ async fn test_edits_around_expanded_insertion_hunks(
 
             println!("world");
         }
-        "#
+      "#
         .unindent(),
     );
 
@@ -12783,7 +12810,7 @@ async fn test_edits_around_expanded_insertion_hunks(
 
             println!("world");
         }
-        "#
+      "#
         .unindent(),
     );
 
@@ -12804,7 +12831,7 @@ async fn test_edits_around_expanded_insertion_hunks(
 
             println!("world");
         }
-        "#
+      "#
         .unindent(),
     );
 }
@@ -12857,7 +12884,7 @@ async fn test_edits_around_expanded_deletion_hunks(
     executor.run_until_parked();
 
     cx.update_editor(|editor, cx| {
-        editor.expand_all_hunk_diffs(&ExpandAllHunkDiffs, cx);
+        editor.expand_all_diff_hunks(&ExpandAllHunkDiffs, cx);
     });
     executor.run_until_parked();
 
@@ -12876,7 +12903,7 @@ async fn test_edits_around_expanded_deletion_hunks(
 
             println!("world");
         }
-        "#
+      "#
         .unindent(),
     );
 
@@ -12899,7 +12926,7 @@ async fn test_edits_around_expanded_deletion_hunks(
 
             println!("world");
         }
-        "#
+      "#
         .unindent(),
     );
 
@@ -12922,7 +12949,7 @@ async fn test_edits_around_expanded_deletion_hunks(
 
             println!("world");
         }
-        "#
+      "#
         .unindent(),
     );
 
@@ -12946,7 +12973,7 @@ async fn test_edits_around_expanded_deletion_hunks(
 
             println!("world");
         }
-        "#
+      "#
         .unindent(),
     );
 }
@@ -12999,7 +13026,7 @@ async fn test_edit_after_expanded_modification_hunk(
     cx.set_diff_base(&diff_base);
     executor.run_until_parked();
     cx.update_editor(|editor, cx| {
-        editor.expand_all_hunk_diffs(&ExpandAllHunkDiffs, cx);
+        editor.expand_all_diff_hunks(&ExpandAllHunkDiffs, cx);
     });
     executor.run_until_parked();
 
@@ -14699,8 +14726,7 @@ fn assert_hunk_revert(
     let reverted_hunk_statuses = cx.update_editor(|editor, cx| {
         let snapshot = editor.snapshot(cx);
         let reverted_hunk_statuses = snapshot
-            .diff_map
-            .diff_hunks_in_range(0..snapshot.buffer_snapshot.len(), &snapshot.buffer_snapshot)
+            .diff_hunks_in_range(0..snapshot.buffer_snapshot.len())
             .map(|hunk| hunk_status(&hunk))
             .collect::<Vec<_>>();
 

crates/editor/src/element.rs

@@ -21,8 +21,8 @@ use crate::{
     DocumentHighlightRead, DocumentHighlightWrite, Editor, EditorMode, EditorSettings,
     EditorSnapshot, EditorStyle, ExpandExcerpts, FocusedBlock, GutterDimensions, HalfPageDown,
     HalfPageUp, HandleInput, HoveredCursor, HoveredHunk, InlineCompletion, JumpData, LineDown,
-    LineUp, OpenExcerpts, PageDown, PageUp, Point, RowExt, RowRangeExt, SelectPhase, Selection,
-    SoftWrap, ToPoint, ToggleFold, CURSORS_VISIBLE_FOR, FILE_HEADER_HEIGHT,
+    LineUp, OpenExcerpts, PageDown, PageUp, Point, RowExt, RowInfo, RowRangeExt, SelectPhase,
+    Selection, SoftWrap, ToPoint, ToggleFold, CURSORS_VISIBLE_FOR, FILE_HEADER_HEIGHT,
     GIT_BLAME_MAX_AUTHOR_CHARS_DISPLAYED, MAX_LINE_LEN, MULTI_BUFFER_EXCERPT_HEADER_HEIGHT,
 };
 use client::ParticipantIndex;
@@ -381,7 +381,7 @@ impl EditorElement {
         register_action(view, cx, Editor::toggle_git_blame);
         register_action(view, cx, Editor::toggle_git_blame_inline);
         register_action(view, cx, Editor::toggle_hunk_diff);
-        register_action(view, cx, Editor::expand_all_hunk_diffs);
+        register_action(view, cx, Editor::expand_all_diff_hunks);
         register_action(view, cx, |editor, action, cx| {
             if let Some(task) = editor.format(action, cx) {
                 task.detach_and_log_err(cx);
@@ -1196,7 +1196,7 @@ impl EditorElement {
                 let editor = self.editor.read(cx);
                 let is_singleton = editor.is_singleton(cx);
                 // Git
-                (is_singleton && scrollbar_settings.git_diff && !snapshot.diff_map.is_empty())
+                (is_singleton && scrollbar_settings.git_diff && snapshot.has_diff_hunks())
                     ||
                     // Buffer Search Results
                     (is_singleton && scrollbar_settings.search_results && editor.has_background_highlights::<BufferSearchHighlights>())
@@ -1461,10 +1461,10 @@ impl EditorElement {
                 .unwrap_err();
             let mut expanded_hunks = expanded_hunks[expanded_hunks_start_ix..].iter().peekable();
 
-            let mut display_hunks: Vec<(DisplayDiffHunk, Option<Hitbox>)> = editor
-                .diff_map
-                .snapshot
-                .diff_hunks_in_range(buffer_start..buffer_end, &buffer_snapshot)
+            let mut display_hunks: Vec<(DisplayDiffHunk, Option<Hitbox>)> = snapshot
+                .display_snapshot
+                .diff_snapshot()
+                .diff_hunks_in_range(buffer_start..buffer_end)
                 .filter_map(|hunk| {
                     let display_hunk = diff_hunk_to_display(&hunk, snapshot);
 
@@ -1532,7 +1532,7 @@ impl EditorElement {
     fn layout_inline_blame(
         &self,
         display_row: DisplayRow,
-        display_snapshot: &DisplaySnapshot,
+        row_info: &RowInfo,
         line_layout: &LineWithInvisibles,
         crease_trailer: Option<&CreaseTrailerLayout>,
         em_width: Pixels,
@@ -1555,13 +1555,10 @@ impl EditorElement {
             .as_ref()
             .map(|(w, _)| w.clone());
 
-        let display_point = DisplayPoint::new(display_row, 0);
-        let buffer_row = MultiBufferRow(display_point.to_point(display_snapshot).row);
-
         let blame = self.editor.read(cx).blame.clone()?;
         let blame_entry = blame
             .update(cx, |blame, cx| {
-                blame.blame_for_rows([Some(buffer_row)], cx).next()
+                blame.blame_for_rows(&[*row_info], cx).next()
             })
             .flatten()?;
 
@@ -1601,7 +1598,7 @@ impl EditorElement {
     #[allow(clippy::too_many_arguments)]
     fn layout_blame_entries(
         &self,
-        buffer_rows: impl Iterator<Item = Option<MultiBufferRow>>,
+        buffer_rows: &[RowInfo],
         em_width: Pixels,
         scroll_position: gpui::Point<f32>,
         line_height: Pixels,
@@ -1938,7 +1935,7 @@ impl EditorElement {
         let end = rows.end.max(relative_to);
 
         let buffer_rows = snapshot
-            .buffer_rows(start)
+            .row_infos(start)
             .take(1 + end.minus(start) as usize)
             .collect::<Vec<_>>();
 
@@ -1946,7 +1943,7 @@ impl EditorElement {
         let mut delta = 1;
         let mut i = head_idx + 1;
         while i < buffer_rows.len() as u32 {
-            if buffer_rows[i as usize].is_some() {
+            if buffer_rows[i as usize].buffer_row.is_some() {
                 if rows.contains(&DisplayRow(i + start.0)) {
                     relative_rows.insert(DisplayRow(i + start.0), delta);
                 }
@@ -1956,13 +1953,13 @@ impl EditorElement {
         }
         delta = 1;
         i = head_idx.min(buffer_rows.len() as u32 - 1);
-        while i > 0 && buffer_rows[i as usize].is_none() {
+        while i > 0 && buffer_rows[i as usize].buffer_row.is_none() {
             i -= 1;
         }
 
         while i > 0 {
             i -= 1;
-            if buffer_rows[i as usize].is_some() {
+            if buffer_rows[i as usize].buffer_row.is_some() {
                 if rows.contains(&DisplayRow(i + start.0)) {
                     relative_rows.insert(DisplayRow(i + start.0), delta);
                 }
@@ -1976,7 +1973,7 @@ impl EditorElement {
     fn layout_line_numbers(
         &self,
         rows: Range<DisplayRow>,
-        buffer_rows: impl Iterator<Item = Option<MultiBufferRow>>,
+        buffer_rows: &[RowInfo],
         active_rows: &BTreeMap<DisplayRow, bool>,
         newest_selection_head: Option<DisplayPoint>,
         snapshot: &EditorSnapshot,
@@ -2018,8 +2015,7 @@ impl EditorElement {
         buffer_rows
             .into_iter()
             .enumerate()
-            .map(|(ix, multibuffer_row)| {
-                let multibuffer_row = multibuffer_row?;
+            .map(|(ix, row_info)| {
                 let display_row = DisplayRow(rows.start.0 + ix as u32);
                 let color = if active_rows.contains_key(&display_row) {
                     cx.theme().colors().editor_active_line_number
@@ -2027,7 +2023,7 @@ impl EditorElement {
                     cx.theme().colors().editor_line_number
                 };
                 line_number.clear();
-                let default_number = multibuffer_row.0 + 1;
+                let default_number = row_info.buffer_row? + 1;
                 let number = relative_rows
                     .get(&DisplayRow(ix as u32 + rows.start.0))
                     .unwrap_or(&default_number);
@@ -2052,7 +2048,7 @@ impl EditorElement {
     fn layout_crease_toggles(
         &self,
         rows: Range<DisplayRow>,
-        buffer_rows: impl IntoIterator<Item = Option<MultiBufferRow>>,
+        row_infos: &[RowInfo],
         active_rows: &BTreeMap<DisplayRow, bool>,
         snapshot: &EditorSnapshot,
         cx: &mut WindowContext,
@@ -2061,22 +2057,21 @@ impl EditorElement {
             && snapshot.mode == EditorMode::Full
             && self.editor.read(cx).is_singleton(cx);
         if include_fold_statuses {
-            buffer_rows
+            row_infos
                 .into_iter()
                 .enumerate()
-                .map(|(ix, row)| {
-                    if let Some(multibuffer_row) = row {
-                        let display_row = DisplayRow(rows.start.0 + ix as u32);
-                        let active = active_rows.contains_key(&display_row);
-                        snapshot.render_crease_toggle(
-                            multibuffer_row,
-                            active,
-                            self.editor.clone(),
-                            cx,
-                        )
-                    } else {
-                        None
-                    }
+                .map(|(ix, info)| {
+                    let row = info.buffer_row?;
+                    let display_row = DisplayRow(rows.start.0 + ix as u32);
+                    let active = active_rows.contains_key(&display_row);
+
+                    // todo(max): Retrieve the multibuffer row correctly
+                    snapshot.render_crease_toggle(
+                        MultiBufferRow(row),
+                        active,
+                        self.editor.clone(),
+                        cx,
+                    )
                 })
                 .collect()
         } else {
@@ -2086,15 +2081,16 @@ impl EditorElement {
 
     fn layout_crease_trailers(
         &self,
-        buffer_rows: impl IntoIterator<Item = Option<MultiBufferRow>>,
+        buffer_rows: impl IntoIterator<Item = RowInfo>,
         snapshot: &EditorSnapshot,
         cx: &mut WindowContext,
     ) -> Vec<Option<AnyElement>> {
         buffer_rows
             .into_iter()
-            .map(|row| {
-                if let Some(multibuffer_row) = row {
-                    snapshot.render_crease_trailer(multibuffer_row, cx)
+            .map(|row_info| {
+                // FIXME: These are not really MultiBufferRow?!
+                if let Some(row) = row_info.buffer_row {
+                    snapshot.render_crease_trailer(MultiBufferRow(row), cx)
                 } else {
                     None
                 }
@@ -4376,32 +4372,29 @@ impl EditorElement {
                             let max_point = snapshot.display_snapshot.buffer_snapshot.max_point();
                             let mut marker_quads = Vec::new();
                             if scrollbar_settings.git_diff {
-                                let marker_row_ranges = snapshot
-                                    .diff_map
-                                    .diff_hunks(&snapshot.buffer_snapshot)
-                                    .map(|hunk| {
-                                        let start_display_row =
-                                            MultiBufferPoint::new(hunk.row_range.start.0, 0)
-                                                .to_display_point(&snapshot.display_snapshot)
-                                                .row();
-                                        let mut end_display_row =
-                                            MultiBufferPoint::new(hunk.row_range.end.0, 0)
-                                                .to_display_point(&snapshot.display_snapshot)
-                                                .row();
-                                        if end_display_row != start_display_row {
-                                            end_display_row.0 -= 1;
-                                        }
-                                        let color = match hunk_status(&hunk) {
-                                            DiffHunkStatus::Added => theme.status().created,
-                                            DiffHunkStatus::Modified => theme.status().modified,
-                                            DiffHunkStatus::Removed => theme.status().deleted,
-                                        };
-                                        ColoredRange {
-                                            start: start_display_row,
-                                            end: end_display_row,
-                                            color,
-                                        }
-                                    });
+                                let marker_row_ranges = snapshot.diff_hunks().map(|hunk| {
+                                    let start_display_row =
+                                        MultiBufferPoint::new(hunk.row_range.start.0, 0)
+                                            .to_display_point(&snapshot.display_snapshot)
+                                            .row();
+                                    let mut end_display_row =
+                                        MultiBufferPoint::new(hunk.row_range.end.0, 0)
+                                            .to_display_point(&snapshot.display_snapshot)
+                                            .row();
+                                    if end_display_row != start_display_row {
+                                        end_display_row.0 -= 1;
+                                    }
+                                    let color = match hunk_status(&hunk) {
+                                        DiffHunkStatus::Added => theme.status().created,
+                                        DiffHunkStatus::Modified => theme.status().modified,
+                                        DiffHunkStatus::Removed => theme.status().deleted,
+                                    };
+                                    ColoredRange {
+                                        start: start_display_row,
+                                        end: end_display_row,
+                                        color,
+                                    }
+                                });
 
                                 marker_quads.extend(
                                     scrollbar_layout
@@ -5820,12 +5813,15 @@ impl Element for EditorElement {
                     );
                     let end_row = DisplayRow(end_row);
 
-                    let buffer_rows = snapshot
-                        .buffer_rows(start_row)
+                    let row_infos = snapshot
+                        .row_infos(start_row)
                         .take((start_row..end_row).len())
-                        .collect::<Vec<_>>();
-                    let is_row_soft_wrapped =
-                        |row| buffer_rows.get(row).copied().flatten().is_none();
+                        .collect::<Vec<RowInfo>>();
+                    let is_row_soft_wrapped = |row: usize| {
+                        row_infos
+                            .get(row)
+                            .map_or(true, |info| info.buffer_row.is_none())
+                    };
 
                     let start_anchor = if start_row == Default::default() {
                         Anchor::min()
@@ -5842,9 +5838,21 @@ impl Element for EditorElement {
                         )
                     };
 
-                    let highlighted_rows = self
+                    let mut highlighted_rows = self
                         .editor
                         .update(cx, |editor, cx| editor.highlighted_display_rows(cx));
+
+                    for (ix, row_info) in row_infos.iter().enumerate() {
+                        let color = match row_info.diff_status {
+                            Some(DiffHunkStatus::Added) => style.status.created_background,
+                            Some(DiffHunkStatus::Removed) => style.status.deleted_background,
+                            _ => continue,
+                        };
+                        highlighted_rows
+                            .entry(start_row + DisplayRow(ix as u32))
+                            .or_insert(color);
+                    }
+
                     let highlighted_ranges = self.editor.read(cx).background_highlights_in_range(
                         start_anchor..end_anchor,
                         &snapshot.display_snapshot,
@@ -5884,7 +5892,7 @@ impl Element for EditorElement {
 
                     let line_numbers = self.layout_line_numbers(
                         start_row..end_row,
-                        buffer_rows.iter().copied(),
+                        &row_infos,
                         &active_rows,
                         newest_selection_head,
                         &snapshot,
@@ -5894,14 +5902,14 @@ impl Element for EditorElement {
                     let mut crease_toggles = cx.with_element_namespace("crease_toggles", |cx| {
                         self.layout_crease_toggles(
                             start_row..end_row,
-                            buffer_rows.iter().copied(),
+                            &row_infos,
                             &active_rows,
                             &snapshot,
                             cx,
                         )
                     });
                     let crease_trailers = cx.with_element_namespace("crease_trailers", |cx| {
-                        self.layout_crease_trailers(buffer_rows.iter().copied(), &snapshot, cx)
+                        self.layout_crease_trailers(row_infos.iter().copied(), &snapshot, cx)
                     });
 
                     let display_hunks = self.layout_gutter_git_hunks(
@@ -6042,11 +6050,12 @@ impl Element for EditorElement {
                         let display_row = newest_selection_head.row();
                         if (start_row..end_row).contains(&display_row) {
                             let line_ix = display_row.minus(start_row) as usize;
+                            let row_info = &row_infos[line_ix];
                             let line_layout = &line_layouts[line_ix];
                             let crease_trailer_layout = crease_trailers[line_ix].as_ref();
                             inline_blame = self.layout_inline_blame(
                                 display_row,
-                                &snapshot.display_snapshot,
+                                row_info,
                                 line_layout,
                                 crease_trailer_layout,
                                 em_width,
@@ -6059,7 +6068,7 @@ impl Element for EditorElement {
                     }
 
                     let blamed_display_rows = self.layout_blame_entries(
-                        buffer_rows.into_iter(),
+                        &row_infos,
                         em_width,
                         scroll_position,
                         line_height,
@@ -6148,22 +6157,6 @@ impl Element for EditorElement {
 
                     let gutter_settings = EditorSettings::get_global(cx).gutter;
 
-                    let expanded_add_hunks_by_rows = self.editor.update(cx, |editor, _| {
-                        editor
-                            .diff_map
-                            .hunks(false)
-                            .filter(|hunk| hunk.status == DiffHunkStatus::Added)
-                            .map(|expanded_hunk| {
-                                let start_row = expanded_hunk
-                                    .hunk_range
-                                    .start
-                                    .to_display_point(&snapshot)
-                                    .row();
-                                (start_row, expanded_hunk.clone())
-                            })
-                            .collect::<HashMap<_, _>>()
-                    });
-
                     let rows_with_hunk_bounds = display_hunks
                         .iter()
                         .filter_map(|(hunk, hitbox)| Some((hunk, hitbox.as_ref()?.bounds)))
@@ -6206,38 +6199,32 @@ impl Element for EditorElement {
                             if show_code_actions {
                                 let newest_selection_point =
                                     newest_selection_head.to_point(&snapshot.display_snapshot);
-                                let newest_selection_display_row =
-                                    newest_selection_point.to_display_point(&snapshot).row();
-                                if !expanded_add_hunks_by_rows
-                                    .contains_key(&newest_selection_display_row)
+                                if !snapshot
+                                    .is_line_folded(MultiBufferRow(newest_selection_point.row))
                                 {
-                                    if !snapshot
-                                        .is_line_folded(MultiBufferRow(newest_selection_point.row))
-                                    {
-                                        let buffer = snapshot.buffer_snapshot.buffer_line_for_row(
-                                            MultiBufferRow(newest_selection_point.row),
-                                        );
-                                        if let Some((buffer, range)) = buffer {
-                                            let buffer_id = buffer.remote_id();
-                                            let row = range.start.row;
-                                            let has_test_indicator = self
-                                                .editor
-                                                .read(cx)
-                                                .tasks
-                                                .contains_key(&(buffer_id, row));
+                                    let buffer = snapshot.buffer_snapshot.buffer_line_for_row(
+                                        MultiBufferRow(newest_selection_point.row),
+                                    );
+                                    if let Some((buffer, range)) = buffer {
+                                        let buffer_id = buffer.remote_id();
+                                        let row = range.start.row;
+                                        let has_test_indicator = self
+                                            .editor
+                                            .read(cx)
+                                            .tasks
+                                            .contains_key(&(buffer_id, row));
 
-                                            if !has_test_indicator {
-                                                code_actions_indicator = self
-                                                    .layout_code_actions_indicator(
-                                                        line_height,
-                                                        newest_selection_head,
-                                                        scroll_pixel_position,
-                                                        &gutter_dimensions,
-                                                        &gutter_hitbox,
-                                                        &rows_with_hunk_bounds,
-                                                        cx,
-                                                    );
-                                            }
+                                        if !has_test_indicator {
+                                            code_actions_indicator = self
+                                                .layout_code_actions_indicator(
+                                                    line_height,
+                                                    newest_selection_head,
+                                                    scroll_pixel_position,
+                                                    &gutter_dimensions,
+                                                    &gutter_hitbox,
+                                                    &rows_with_hunk_bounds,
+                                                    cx,
+                                                );
                                         }
                                     }
                                 }
@@ -7209,7 +7196,12 @@ mod tests {
             .update_window(*window, |_, cx| {
                 element.layout_line_numbers(
                     DisplayRow(0)..DisplayRow(6),
-                    (0..6).map(MultiBufferRow).map(Some),
+                    &(0..6)
+                        .map(|row| RowInfo {
+                            buffer_row: Some(row),
+                            ..Default::default()
+                        })
+                        .collect::<Vec<_>>(),
                     &Default::default(),
                     Some(DisplayPoint::new(DisplayRow(0), 0)),
                     &snapshot,

crates/editor/src/git/blame.rs

@@ -9,12 +9,13 @@ use git::{
 use gpui::{Model, ModelContext, Subscription, Task};
 use http_client::HttpClient;
 use language::{markdown, Bias, Buffer, BufferSnapshot, Edit, LanguageRegistry, ParsedMarkdown};
-use multi_buffer::MultiBufferRow;
 use project::{Project, ProjectItem};
 use smallvec::SmallVec;
 use sum_tree::SumTree;
 use url::Url;
 
+use crate::RowInfo;
+
 #[derive(Clone, Debug, Default)]
 pub struct GitBlameEntry {
     pub rows: u32,
@@ -194,15 +195,15 @@ impl GitBlame {
 
     pub fn blame_for_rows<'a>(
         &'a mut self,
-        rows: impl 'a + IntoIterator<Item = Option<MultiBufferRow>>,
+        rows: &'a [RowInfo],
         cx: &mut ModelContext<Self>,
     ) -> impl 'a + Iterator<Item = Option<BlameEntry>> {
         self.sync(cx);
 
         let mut cursor = self.entries.cursor::<u32>(&());
-        rows.into_iter().map(move |row| {
-            let row = row?;
-            cursor.seek_forward(&row.0, Bias::Right, &());
+        rows.into_iter().map(move |info| {
+            let row = info.buffer_row?;
+            cursor.seek_forward(&row, Bias::Right, &());
             cursor.item()?.blame.clone()
         })
     }
@@ -563,15 +564,38 @@ mod tests {
     use unindent::Unindent as _;
     use util::RandomCharIter;
 
-    macro_rules! assert_blame_rows {
-        ($blame:expr, $rows:expr, $expected:expr, $cx:expr) => {
-            assert_eq!(
-                $blame
-                    .blame_for_rows($rows.map(MultiBufferRow).map(Some), $cx)
-                    .collect::<Vec<_>>(),
-                $expected
-            );
-        };
+    // macro_rules! assert_blame_rows {
+    //     ($blame:expr, $rows:expr, $expected:expr, $cx:expr) => {
+    //         assert_eq!(
+    //             $blame
+    //                 .blame_for_rows($rows.map(MultiBufferRow).map(Some), $cx)
+    //                 .collect::<Vec<_>>(),
+    //             $expected
+    //         );
+    //     };
+    // }
+
+    #[track_caller]
+    fn assert_blame_rows(
+        blame: &mut GitBlame,
+        rows: Range<u32>,
+        expected: Vec<Option<BlameEntry>>,
+        cx: &mut ModelContext<GitBlame>,
+    ) {
+        assert_eq!(
+            blame
+                .blame_for_rows(
+                    &rows
+                        .map(|row| RowInfo {
+                            buffer_row: Some(row),
+                            ..Default::default()
+                        })
+                        .collect::<Vec<_>>(),
+                    cx
+                )
+                .collect::<Vec<_>>(),
+            expected
+        );
     }
 
     fn init_test(cx: &mut gpui::TestAppContext) {
@@ -634,7 +658,15 @@ mod tests {
         blame.update(cx, |blame, cx| {
             assert_eq!(
                 blame
-                    .blame_for_rows((0..1).map(MultiBufferRow).map(Some), cx)
+                    .blame_for_rows(
+                        &(0..1)
+                            .map(|row| RowInfo {
+                                buffer_row: Some(row),
+                                ..Default::default()
+                            })
+                            .collect::<Vec<_>>(),
+                        cx
+                    )
                     .collect::<Vec<_>>(),
                 vec![None]
             );
@@ -698,7 +730,15 @@ mod tests {
             // All lines
             assert_eq!(
                 blame
-                    .blame_for_rows((0..8).map(MultiBufferRow).map(Some), cx)
+                    .blame_for_rows(
+                        &(0..8)
+                            .map(|buffer_row| RowInfo {
+                                buffer_row: Some(buffer_row),
+                                ..Default::default()
+                            })
+                            .collect::<Vec<_>>(),
+                        cx
+                    )
                     .collect::<Vec<_>>(),
                 vec![
                     Some(blame_entry("1b1b1b", 0..1)),
@@ -714,7 +754,15 @@ mod tests {
             // Subset of lines
             assert_eq!(
                 blame
-                    .blame_for_rows((1..4).map(MultiBufferRow).map(Some), cx)
+                    .blame_for_rows(
+                        &(1..4)
+                            .map(|buffer_row| RowInfo {
+                                buffer_row: Some(buffer_row),
+                                ..Default::default()
+                            })
+                            .collect::<Vec<_>>(),
+                        cx
+                    )
                     .collect::<Vec<_>>(),
                 vec![
                     Some(blame_entry("0d0d0d", 1..2)),
@@ -725,7 +773,17 @@ mod tests {
             // Subset of lines, with some not displayed
             assert_eq!(
                 blame
-                    .blame_for_rows(vec![Some(MultiBufferRow(1)), None, None], cx)
+                    .blame_for_rows(
+                        &[
+                            RowInfo {
+                                buffer_row: Some(1),
+                                ..Default::default()
+                            },
+                            Default::default(),
+                            Default::default(),
+                        ],
+                        cx
+                    )
                     .collect::<Vec<_>>(),
                 vec![Some(blame_entry("0d0d0d", 1..2)), None, None]
             );
@@ -777,16 +835,16 @@ mod tests {
         git_blame.update(cx, |blame, cx| {
             // Sanity check before edits: make sure that we get the same blame entry for all
             // lines.
-            assert_blame_rows!(
+            assert_blame_rows(
                 blame,
-                (0..4),
+                0..4,
                 vec![
                     Some(blame_entry("1b1b1b", 0..4)),
                     Some(blame_entry("1b1b1b", 0..4)),
                     Some(blame_entry("1b1b1b", 0..4)),
                     Some(blame_entry("1b1b1b", 0..4)),
                 ],
-                cx
+                cx,
             );
         });
 
@@ -795,11 +853,11 @@ mod tests {
             buffer.edit([(Point::new(0, 0)..Point::new(0, 0), "X")], None, cx);
         });
         git_blame.update(cx, |blame, cx| {
-            assert_blame_rows!(
+            assert_blame_rows(
                 blame,
-                (0..2),
+                0..2,
                 vec![None, Some(blame_entry("1b1b1b", 0..4))],
-                cx
+                cx,
             );
         });
         // Modify a single line, in the middle of the line
@@ -807,21 +865,21 @@ mod tests {
             buffer.edit([(Point::new(1, 2)..Point::new(1, 2), "X")], None, cx);
         });
         git_blame.update(cx, |blame, cx| {
-            assert_blame_rows!(
+            assert_blame_rows(
                 blame,
-                (1..4),
+                1..4,
                 vec![
                     None,
                     Some(blame_entry("1b1b1b", 0..4)),
-                    Some(blame_entry("1b1b1b", 0..4))
+                    Some(blame_entry("1b1b1b", 0..4)),
                 ],
-                cx
+                cx,
             );
         });
 
         // Before we insert a newline at the end, sanity check:
         git_blame.update(cx, |blame, cx| {
-            assert_blame_rows!(blame, (3..4), vec![Some(blame_entry("1b1b1b", 0..4))], cx);
+            assert_blame_rows(blame, 3..4, vec![Some(blame_entry("1b1b1b", 0..4))], cx);
         });
         // Insert a newline at the end
         buffer.update(cx, |buffer, cx| {
@@ -829,17 +887,17 @@ mod tests {
         });
         // Only the new line is marked as edited:
         git_blame.update(cx, |blame, cx| {
-            assert_blame_rows!(
+            assert_blame_rows(
                 blame,
-                (3..5),
+                3..5,
                 vec![Some(blame_entry("1b1b1b", 0..4)), None],
-                cx
+                cx,
             );
         });
 
         // Before we insert a newline at the start, sanity check:
         git_blame.update(cx, |blame, cx| {
-            assert_blame_rows!(blame, (2..3), vec![Some(blame_entry("1b1b1b", 0..4)),], cx);
+            assert_blame_rows(blame, 2..3, vec![Some(blame_entry("1b1b1b", 0..4))], cx);
         });
 
         // Usage example
@@ -849,11 +907,11 @@ mod tests {
         });
         // Only the new line is marked as edited:
         git_blame.update(cx, |blame, cx| {
-            assert_blame_rows!(
+            assert_blame_rows(
                 blame,
-                (2..4),
-                vec![None, Some(blame_entry("1b1b1b", 0..4)),],
-                cx
+                2..4,
+                vec![None, Some(blame_entry("1b1b1b", 0..4))],
+                cx,
             );
         });
     }

crates/editor/src/git/project_diff.rs

@@ -150,7 +150,7 @@ impl ProjectDiffEditor {
         let editor = cx.new_view(|cx| {
             let mut diff_display_editor =
                 Editor::for_multibuffer(excerpts.clone(), Some(project.clone()), true, cx);
-            diff_display_editor.set_expand_all_diff_hunks();
+            diff_display_editor.set_expand_all_diff_hunks(cx);
             diff_display_editor
         });
 
@@ -311,9 +311,11 @@ impl ProjectDiffEditor {
                     .update(&mut cx, |project_diff_editor, cx| {
                         project_diff_editor.update_excerpts(id, new_changes, new_entry_order, cx);
                         project_diff_editor.editor.update(cx, |editor, cx| {
-                            for change_set in change_sets {
-                                editor.diff_map.add_change_set(change_set, cx)
-                            }
+                            editor.display_map.update(cx, |display_map, cx| {
+                                for change_set in change_sets {
+                                    display_map.add_change_set(change_set, cx)
+                                }
+                            });
                         });
                     })
                     .ok();
@@ -1193,9 +1195,9 @@ mod tests {
                     cx,
                 )
             });
-            file_a_editor
-                .diff_map
-                .add_change_set(change_set.clone(), cx);
+            file_a_editor.display_map.update(cx, |display_map, cx| {
+                display_map.add_change_set(change_set.clone(), cx)
+            });
             project.update(cx, |project, cx| {
                 project.buffer_store().update(cx, |buffer_store, cx| {
                     buffer_store.set_change_set(

crates/editor/src/hunk_diff.rs

@@ -6,11 +6,10 @@ use gpui::{
 use language::{Buffer, BufferId, Point};
 use multi_buffer::{
     Anchor, AnchorRangeExt, ExcerptRange, MultiBuffer, MultiBufferDiffHunk, MultiBufferRow,
-    MultiBufferSnapshot, ToOffset, ToPoint,
+    MultiBufferSnapshot, ToPoint,
 };
 use project::buffer_store::BufferChangeSet;
 use std::{ops::Range, sync::Arc};
-use sum_tree::TreeMap;
 use text::OffsetRangeExt;
 use ui::{
     prelude::*, ActiveTheme, ContextMenu, IconButtonShape, InteractiveElement, IntoElement,
@@ -20,10 +19,10 @@ use util::RangeExt;
 use workspace::Item;
 
 use crate::{
-    editor_settings::CurrentLineHighlight, hunk_status, hunks_for_selections, ApplyAllDiffHunks,
-    ApplyDiffHunk, BlockPlacement, BlockProperties, BlockStyle, CustomBlockId, DiffRowHighlight,
-    DisplayRow, DisplaySnapshot, Editor, EditorElement, ExpandAllHunkDiffs, GoToHunk, GoToPrevHunk,
-    RevertFile, RevertSelectedHunks, ToDisplayPoint, ToggleHunkDiff,
+    editor_settings::CurrentLineHighlight, hunk_status, ApplyAllDiffHunks, ApplyDiffHunk,
+    BlockPlacement, BlockProperties, BlockStyle, CustomBlockId, DiffRowHighlight, DisplayRow,
+    DisplaySnapshot, Editor, EditorElement, GoToHunk, GoToPrevHunk, RevertFile,
+    RevertSelectedHunks, ToDisplayPoint, ToggleHunkDiff,
 };
 
 #[derive(Debug, Clone)]
@@ -37,7 +36,6 @@ pub(super) struct HoveredHunk {
 pub(super) struct DiffMap {
     pub(crate) hunks: Vec<ExpandedHunk>,
     pub(crate) diff_bases: HashMap<BufferId, DiffBaseState>,
-    pub(crate) snapshot: DiffMapSnapshot,
     hunk_update_tasks: HashMap<Option<BufferId>, Task<()>>,
     expand_all: bool,
 }
@@ -51,9 +49,6 @@ pub(super) struct ExpandedHunk {
     pub folded: bool,
 }
 
-#[derive(Clone, Debug, Default)]
-pub(crate) struct DiffMapSnapshot(TreeMap<BufferId, git::diff::BufferDiff>);
-
 pub(crate) struct DiffBaseState {
     pub(crate) change_set: Model<BufferChangeSet>,
     pub(crate) last_version: Option<usize>,
@@ -74,133 +69,7 @@ pub enum DisplayDiffHunk {
     },
 }
 
-impl DiffMap {
-    pub fn snapshot(&self) -> DiffMapSnapshot {
-        self.snapshot.clone()
-    }
-
-    pub fn add_change_set(
-        &mut self,
-        change_set: Model<BufferChangeSet>,
-        cx: &mut ViewContext<Editor>,
-    ) {
-        let buffer_id = change_set.read(cx).buffer_id;
-        self.snapshot
-            .0
-            .insert(buffer_id, change_set.read(cx).diff_to_buffer.clone());
-        self.diff_bases.insert(
-            buffer_id,
-            DiffBaseState {
-                last_version: None,
-                _subscription: cx.observe(&change_set, move |editor, change_set, cx| {
-                    editor
-                        .diff_map
-                        .snapshot
-                        .0
-                        .insert(buffer_id, change_set.read(cx).diff_to_buffer.clone());
-                    Editor::sync_expanded_diff_hunks(&mut editor.diff_map, buffer_id, cx);
-                }),
-                change_set,
-            },
-        );
-        Editor::sync_expanded_diff_hunks(self, buffer_id, cx);
-    }
-
-    pub fn hunks(&self, include_folded: bool) -> impl Iterator<Item = &ExpandedHunk> {
-        self.hunks
-            .iter()
-            .filter(move |hunk| include_folded || !hunk.folded)
-    }
-}
-
-impl DiffMapSnapshot {
-    pub fn is_empty(&self) -> bool {
-        self.0.values().all(|diff| diff.is_empty())
-    }
-
-    pub fn diff_hunks<'a>(
-        &'a self,
-        buffer_snapshot: &'a MultiBufferSnapshot,
-    ) -> impl Iterator<Item = MultiBufferDiffHunk> + 'a {
-        self.diff_hunks_in_range(0..buffer_snapshot.len(), buffer_snapshot)
-    }
-
-    pub fn diff_hunks_in_range<'a, T: ToOffset>(
-        &'a self,
-        range: Range<T>,
-        buffer_snapshot: &'a MultiBufferSnapshot,
-    ) -> impl Iterator<Item = MultiBufferDiffHunk> + 'a {
-        let range = range.start.to_offset(buffer_snapshot)..range.end.to_offset(buffer_snapshot);
-        buffer_snapshot
-            .excerpts_for_range(range.clone())
-            .filter_map(move |excerpt| {
-                let buffer = excerpt.buffer();
-                let buffer_id = buffer.remote_id();
-                let diff = self.0.get(&buffer_id)?;
-                let buffer_range = excerpt.map_range_to_buffer(range.clone());
-                let buffer_range =
-                    buffer.anchor_before(buffer_range.start)..buffer.anchor_after(buffer_range.end);
-                Some(
-                    diff.hunks_intersecting_range(buffer_range, excerpt.buffer())
-                        .map(move |hunk| {
-                            let start =
-                                excerpt.map_point_from_buffer(Point::new(hunk.row_range.start, 0));
-                            let end =
-                                excerpt.map_point_from_buffer(Point::new(hunk.row_range.end, 0));
-                            MultiBufferDiffHunk {
-                                row_range: MultiBufferRow(start.row)..MultiBufferRow(end.row),
-                                buffer_id,
-                                buffer_range: hunk.buffer_range.clone(),
-                                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
-                            }
-                        }),
-                )
-            })
-            .flatten()
-    }
-
-    pub fn diff_hunks_in_range_rev<'a, T: ToOffset>(
-        &'a self,
-        range: Range<T>,
-        buffer_snapshot: &'a MultiBufferSnapshot,
-    ) -> impl Iterator<Item = MultiBufferDiffHunk> + 'a {
-        let range = range.start.to_offset(buffer_snapshot)..range.end.to_offset(buffer_snapshot);
-        buffer_snapshot
-            .excerpts_for_range_rev(range.clone())
-            .filter_map(move |excerpt| {
-                let buffer = excerpt.buffer();
-                let buffer_id = buffer.remote_id();
-                let diff = self.0.get(&buffer_id)?;
-                let buffer_range = excerpt.map_range_to_buffer(range.clone());
-                let buffer_range =
-                    buffer.anchor_before(buffer_range.start)..buffer.anchor_after(buffer_range.end);
-                Some(
-                    diff.hunks_intersecting_range_rev(buffer_range, excerpt.buffer())
-                        .map(move |hunk| {
-                            let start_row = excerpt
-                                .map_point_from_buffer(Point::new(hunk.row_range.start, 0))
-                                .row;
-                            let end_row = excerpt
-                                .map_point_from_buffer(Point::new(hunk.row_range.end, 0))
-                                .row;
-                            MultiBufferDiffHunk {
-                                row_range: MultiBufferRow(start_row)..MultiBufferRow(end_row),
-                                buffer_id,
-                                buffer_range: hunk.buffer_range.clone(),
-                                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
-                            }
-                        }),
-                )
-            })
-            .flatten()
-    }
-}
-
 impl Editor {
-    pub fn set_expand_all_diff_hunks(&mut self) {
-        self.diff_map.expand_all = true;
-    }
-
     pub(super) fn toggle_hovered_hunk(
         &mut self,
         hovered_hunk: &HoveredHunk,
@@ -213,47 +82,6 @@ impl Editor {
         }
     }
 
-    pub fn toggle_hunk_diff(&mut self, _: &ToggleHunkDiff, cx: &mut ViewContext<Self>) {
-        let snapshot = self.snapshot(cx);
-        let selections = self.selections.all(cx);
-        self.toggle_hunks_expanded(hunks_for_selections(&snapshot, &selections), cx);
-    }
-
-    pub fn expand_all_hunk_diffs(&mut self, _: &ExpandAllHunkDiffs, cx: &mut ViewContext<Self>) {
-        let snapshot = self.snapshot(cx);
-        let display_rows_with_expanded_hunks = self
-            .diff_map
-            .hunks(false)
-            .map(|hunk| &hunk.hunk_range)
-            .map(|anchor_range| {
-                (
-                    anchor_range
-                        .start
-                        .to_display_point(&snapshot.display_snapshot)
-                        .row(),
-                    anchor_range
-                        .end
-                        .to_display_point(&snapshot.display_snapshot)
-                        .row(),
-                )
-            })
-            .collect::<HashMap<_, _>>();
-        let hunks = self
-            .diff_map
-            .snapshot
-            .diff_hunks(&snapshot.display_snapshot.buffer_snapshot)
-            .filter(|hunk| {
-                let hunk_display_row_range = Point::new(hunk.row_range.start.0, 0)
-                    .to_display_point(&snapshot.display_snapshot)
-                    ..Point::new(hunk.row_range.end.0, 0)
-                        .to_display_point(&snapshot.display_snapshot);
-                let row_range_end =
-                    display_rows_with_expanded_hunks.get(&hunk_display_row_range.start.row());
-                row_range_end.is_none() || row_range_end != Some(&hunk_display_row_range.end.row())
-            });
-        self.toggle_hunks_expanded(hunks.collect(), cx);
-    }
-
     fn toggle_hunks_expanded(
         &mut self,
         hunks_to_toggle: Vec<MultiBufferDiffHunk>,
@@ -497,7 +325,8 @@ impl Editor {
         cx: &mut ViewContext<Self>,
     ) {
         let snapshot = self.snapshot(cx);
-        let hunks = hunks_for_selections(&snapshot, &self.selections.all(cx));
+        let ranges = self.selections.all(cx).into_iter().map(|s| s.range());
+        let hunks = snapshot.hunks_for_ranges(ranges);
         let mut ranges_by_buffer = HashMap::default();
         self.transact(cx, |editor, cx| {
             for hunk in hunks {
@@ -521,10 +350,8 @@ impl Editor {
         }
     }
 
-    fn has_multiple_hunks(&self, cx: &AppContext) -> bool {
-        let snapshot = self.buffer.read(cx).snapshot(cx);
-        let mut hunks = self.diff_map.snapshot.diff_hunks(&snapshot);
-        hunks.nth(1).is_some()
+    fn has_multiple_hunks(&self, cx: &mut WindowContext) -> bool {
+        self.display_map.read(cx).has_multiple_hunks(cx)
     }
 
     fn hunk_header_block(
@@ -865,23 +692,15 @@ impl Editor {
     }
 
     pub(super) fn clear_expanded_diff_hunks(&mut self, cx: &mut ViewContext<'_, Editor>) -> bool {
-        if self.diff_map.expand_all {
-            return false;
-        }
-        self.diff_map.hunk_update_tasks.clear();
-        self.clear_row_highlights::<DiffRowHighlight>();
-        let to_remove = self
-            .diff_map
-            .hunks
-            .drain(..)
-            .flat_map(|expanded_hunk| expanded_hunk.blocks.into_iter())
-            .collect::<HashSet<_>>();
-        if to_remove.is_empty() {
-            false
-        } else {
-            self.remove_blocks(to_remove, None, cx);
-            true
-        }
+        self.display_map.update(cx, |diff_map, cx| {
+            let ranges = vec![Anchor::min()..Anchor::max()];
+            if diff_map.has_expanded_diff_hunks_in_ranges(&ranges, cx) {
+                diff_map.collapse_diff_hunks(ranges, cx);
+                true
+            } else {
+                false
+            }
+        })
     }
 
     pub(super) fn sync_expanded_diff_hunks(
@@ -909,8 +728,7 @@ impl Editor {
                 .update(&mut cx, |editor, cx| {
                     let snapshot = editor.snapshot(cx);
                     let mut recalculated_hunks = snapshot
-                        .diff_map
-                        .diff_hunks(&snapshot.buffer_snapshot)
+                        .diff_hunks()
                         .filter(|hunk| hunk.buffer_id == buffer_id)
                         .fuse()
                         .peekable();
@@ -1418,7 +1236,9 @@ mod tests {
                             cx,
                         )
                     });
-                    editor.diff_map.add_change_set(change_set, cx)
+                    editor.display_map.update(cx, |display_map, cx| {
+                        display_map.add_change_set(change_set, cx)
+                    });
                 }
             })
             .unwrap();
@@ -1470,8 +1290,7 @@ mod tests {
 
         assert_eq!(
             snapshot
-                .diff_map
-                .diff_hunks_in_range(Point::zero()..Point::new(12, 0), &snapshot.buffer_snapshot)
+                .diff_hunks_in_range(Point::zero()..Point::new(12, 0))
                 .map(|hunk| (hunk_status(&hunk), hunk.row_range))
                 .collect::<Vec<_>>(),
             &expected,
@@ -1479,11 +1298,7 @@ mod tests {
 
         assert_eq!(
             snapshot
-                .diff_map
-                .diff_hunks_in_range_rev(
-                    Point::zero()..Point::new(12, 0),
-                    &snapshot.buffer_snapshot
-                )
+                .diff_hunks_in_range_rev(Point::zero()..Point::new(12, 0))
                 .map(|hunk| (hunk_status(&hunk), hunk.row_range))
                 .collect::<Vec<_>>(),
             expected

crates/editor/src/proposed_changes_editor.rs

@@ -61,7 +61,7 @@ impl ProposedChangesEditor {
         let mut this = Self {
             editor: cx.new_view(|cx| {
                 let mut editor = Editor::for_multibuffer(multibuffer.clone(), project, true, cx);
-                editor.set_expand_all_diff_hunks();
+                editor.set_expand_all_diff_hunks(cx);
                 editor.set_completion_provider(None);
                 editor.clear_code_action_providers();
                 editor.set_semantics_provider(
@@ -223,9 +223,11 @@ impl ProposedChangesEditor {
         self.buffer_entries = buffer_entries;
         self.editor.update(cx, |editor, cx| {
             editor.change_selections(None, cx, |selections| selections.refresh());
-            for change_set in new_change_sets {
-                editor.diff_map.add_change_set(change_set, cx)
-            }
+            editor.display_map.update(cx, |display_map, cx| {
+                for change_set in new_change_sets {
+                    display_map.add_change_set(change_set, cx)
+                }
+            })
         });
     }
 

crates/editor/src/test/editor_test_context.rs

@@ -1,6 +1,6 @@
 use crate::{
-    display_map::ToDisplayPoint, AnchorRangeExt, Autoscroll, DiffRowHighlight, DisplayPoint,
-    Editor, MultiBuffer, RowExt,
+    display_map::ToDisplayPoint, AnchorRangeExt, Autoscroll, DisplayPoint, Editor, MultiBuffer,
+    RowExt,
 };
 use collections::BTreeMap;
 use futures::Future;
@@ -11,11 +11,12 @@ use gpui::{
 };
 use itertools::Itertools;
 use language::{Buffer, BufferSnapshot, LanguageRegistry};
-use multi_buffer::{ExcerptRange, ToPoint};
+use multi_buffer::ExcerptRange;
 use parking_lot::RwLock;
 use project::{FakeFs, Project};
 use std::{
     any::TypeId,
+    cmp,
     ops::{Deref, DerefMut, Range},
     path::Path,
     sync::{
@@ -23,6 +24,7 @@ use std::{
         Arc,
     },
 };
+use text::Bias;
 use util::{
     assert_set_eq,
     test::{generate_marked_text, marked_text_ranges},
@@ -332,83 +334,51 @@ impl EditorTestContext {
     ///
     /// Diff hunks are indicated by lines starting with `+` and `-`.
     #[track_caller]
-    pub fn assert_state_with_diff(&mut self, expected_diff: String) {
-        let has_diff_markers = expected_diff
-            .lines()
-            .any(|line| line.starts_with("+") || line.starts_with("-"));
-        let expected_diff_text = expected_diff
-            .split('\n')
-            .map(|line| {
-                let trimmed = line.trim();
-                if trimmed.is_empty() {
-                    String::new()
-                } else if has_diff_markers {
-                    line.to_string()
-                } else {
-                    format!("  {line}")
-                }
-            })
-            .join("\n");
+    pub fn assert_state_with_diff(&mut self, expected_diff_text: String) {
+        let (snapshot, selections) = self
+            .editor
+            .update(&mut self.cx, |editor, cx| editor.selections.all_display(cx));
 
-        let actual_selections = self.editor_selections();
-        let actual_marked_text =
-            generate_marked_text(&self.buffer_text(), &actual_selections, true);
+        let diff_snapshot = snapshot.diff_snapshot();
+        let diff_offsets = selections
+            .into_iter()
+            .map(|s| {
+                let start = snapshot.display_point_to_diff_offset(s.start, Bias::Left).0;
+                let end = snapshot.display_point_to_diff_offset(s.end, Bias::Left).0;
+                cmp::min(start, end)..cmp::max(start, end)
+            })
+            .collect::<Vec<_>>();
+
+        let actual_marked_text = generate_marked_text(&diff_snapshot.text(), &diff_offsets, true);
 
         // Read the actual diff from the editor's row highlights and block
         // decorations.
-        let actual_diff = self.editor.update(&mut self.cx, |editor, cx| {
-            let snapshot = editor.snapshot(cx);
-            let insertions = editor
-                .highlighted_rows::<DiffRowHighlight>()
-                .map(|(range, _)| {
-                    let start = range.start.to_point(&snapshot.buffer_snapshot);
-                    let end = range.end.to_point(&snapshot.buffer_snapshot);
-                    start.row..end.row
-                })
-                .collect::<Vec<_>>();
-            let deletions = editor
-                .diff_map
-                .hunks
-                .iter()
-                .filter_map(|hunk| {
-                    if hunk.blocks.is_empty() {
-                        return None;
+        let line_infos = diff_snapshot.row_infos(0).collect::<Vec<_>>();
+        let has_diff = line_infos.iter().any(|info| info.diff_status.is_some());
+
+        let actual_diff = actual_marked_text
+            .split('\n')
+            .zip(line_infos)
+            .map(|(line, info)| {
+                let mut marker = match info.diff_status {
+                    Some(DiffHunkStatus::Added) => "+ ",
+                    Some(DiffHunkStatus::Removed) => "- ",
+                    Some(DiffHunkStatus::Modified) => unreachable!(),
+                    None => {
+                        if has_diff {
+                            "  "
+                        } else {
+                            ""
+                        }
                     }
-                    let row = hunk
-                        .hunk_range
-                        .start
-                        .to_point(&snapshot.buffer_snapshot)
-                        .row;
-                    let (_, buffer, _) = editor
-                        .buffer()
-                        .read(cx)
-                        .excerpt_containing(hunk.hunk_range.start, cx)
-                        .expect("no excerpt for expanded buffer's hunk start");
-                    let buffer_id = buffer.read(cx).remote_id();
-                    let change_set = &editor
-                        .diff_map
-                        .diff_bases
-                        .get(&buffer_id)
-                        .expect("should have a diff base for expanded hunk")
-                        .change_set;
-                    let deleted_text = change_set
-                        .read(cx)
-                        .base_text
-                        .as_ref()
-                        .expect("no base text for expanded hunk")
-                        .read(cx)
-                        .as_rope()
-                        .slice(hunk.diff_base_byte_range.clone())
-                        .to_string();
-                    if let DiffHunkStatus::Modified | DiffHunkStatus::Removed = hunk.status {
-                        Some((row, deleted_text))
-                    } else {
-                        None
-                    }
-                })
-                .collect::<Vec<_>>();
-            format_diff(actual_marked_text, deletions, insertions)
-        });
+                };
+                if line.is_empty() {
+                    marker = marker.trim();
+                }
+                format!("{marker}{line}")
+            })
+            .collect::<Vec<_>>()
+            .join("\n");
 
         pretty_assertions::assert_eq!(actual_diff, expected_diff_text, "unexpected diff state");
     }
@@ -503,46 +473,6 @@ impl EditorTestContext {
     }
 }
 
-fn format_diff(
-    text: String,
-    actual_deletions: Vec<(u32, String)>,
-    actual_insertions: Vec<Range<u32>>,
-) -> String {
-    let mut diff = String::new();
-    for (row, line) in text.split('\n').enumerate() {
-        let row = row as u32;
-        if row > 0 {
-            diff.push('\n');
-        }
-        if let Some(text) = actual_deletions
-            .iter()
-            .find_map(|(deletion_row, deleted_text)| {
-                if *deletion_row == row {
-                    Some(deleted_text)
-                } else {
-                    None
-                }
-            })
-        {
-            for line in text.lines() {
-                diff.push('-');
-                if !line.is_empty() {
-                    diff.push(' ');
-                    diff.push_str(line);
-                }
-                diff.push('\n');
-            }
-        }
-        let marker = if actual_insertions.iter().any(|range| range.contains(&row)) {
-            "+ "
-        } else {
-            "  "
-        };
-        diff.push_str(format!("{marker}{line}").trim_end());
-    }
-    diff
-}
-
 impl Deref for EditorTestContext {
     type Target = gpui::VisualTestContext;
 

crates/multi_buffer/Cargo.toml

@@ -27,11 +27,13 @@ collections.workspace = true
 ctor.workspace = true
 env_logger.workspace = true
 futures.workspace = true
+git.workspace = true
 gpui.workspace = true
 itertools.workspace = true
 language.workspace = true
 log.workspace = true
 parking_lot.workspace = true
+project.workspace = true
 rand.workspace = true
 settings.workspace = true
 serde.workspace = true

crates/multi_buffer/src/multi_buffer.rs

@@ -1,9 +1,11 @@
 mod anchor;
+mod diff_map;
 
 pub use anchor::{Anchor, AnchorRangeExt, Offset};
 use anyhow::{anyhow, Result};
 use clock::ReplicaId;
 use collections::{BTreeMap, Bound, HashMap, HashSet};
+pub use diff_map::*;
 use futures::{channel::mpsc, SinkExt};
 use gpui::{AppContext, EntityId, EventEmitter, Model, ModelContext, Task};
 use itertools::Itertools;
@@ -69,6 +71,7 @@ pub struct MultiBuffer {
     history: History,
     title: Option<String>,
     capability: Capability,
+    diff_map: Model<DiffMap>,
 }
 
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -179,6 +182,7 @@ struct BufferState {
 pub struct MultiBufferSnapshot {
     singleton: bool,
     excerpts: SumTree<Excerpt>,
+    // diff_map_snapshot: DiffMapSnapshot,
     excerpt_ids: SumTree<ExcerptIdMapping>,
     trailing_excerpt_update_count: usize,
     non_text_state_update_count: usize,
@@ -1547,6 +1551,36 @@ impl MultiBuffer {
         excerpts
     }
 
+    pub fn ranges_for_buffer(
+        &self,
+        buffer_id: BufferId,
+        cx: &AppContext,
+    ) -> Vec<(ExcerptId, Range<Point>, Range<text::Anchor>)> {
+        let mut ranges = Vec::new();
+        let snapshot = self.read(cx);
+        for locator in self
+            .buffers
+            .borrow()
+            .get(&buffer_id)
+            .map(|state| &state.excerpts)
+            .into_iter()
+            .flatten()
+        {
+            let mut cursor = snapshot.excerpts.cursor::<(Option<&Locator>, Point)>(&());
+            cursor.seek_forward(&Some(locator), Bias::Left, &());
+            if let Some(excerpt) = cursor.item() {
+                if excerpt.locator == *locator {
+                    ranges.push((
+                        excerpt.id,
+                        cursor.start().1..cursor.end(&()).1,
+                        excerpt.range.context.clone(),
+                    ));
+                }
+            }
+        }
+        ranges
+    }
+
     pub fn excerpt_ranges_for_buffer(
         &self,
         buffer_id: BufferId,
@@ -2529,6 +2563,39 @@ impl MultiBufferSnapshot {
                 .eq(needle.bytes())
     }
 
+    pub fn range_to_buffer_ranges<T: ToOffset>(
+        &self,
+        range: Range<T>,
+    ) -> Vec<(BufferSnapshot, Range<usize>, ExcerptId)> {
+        let start = range.start.to_offset(&self);
+        let end = range.end.to_offset(&self);
+
+        let mut result = Vec::new();
+        let mut cursor = self.excerpts.cursor::<usize>(&());
+        cursor.seek(&start, Bias::Right, &());
+        if cursor.item().is_none() {
+            cursor.prev(&());
+        }
+
+        while let Some(excerpt) = cursor.item() {
+            if *cursor.start() > end {
+                break;
+            }
+
+            let mut end_before_newline = cursor.end(&());
+            if excerpt.has_trailing_newline {
+                end_before_newline -= 1;
+            }
+            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
+            let start = excerpt_start + (cmp::max(start, *cursor.start()) - *cursor.start());
+            let end = excerpt_start + (cmp::min(end, end_before_newline) - *cursor.start());
+            result.push((excerpt.buffer.clone(), start..end, excerpt.id));
+            cursor.next(&());
+        }
+
+        result
+    }
+
     pub fn surrounding_word<T: ToOffset>(
         &self,
         start: T,
@@ -4080,6 +4147,17 @@ impl MultiBufferSnapshot {
         }
     }
 
+    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
+        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
+        let locator = self.excerpt_locator_for_id(excerpt_id);
+        if cursor.seek(&Some(locator), Bias::Left, &()) {
+            if let Some(excerpt) = cursor.item() {
+                return Some(excerpt.range.context.clone());
+            }
+        }
+        None
+    }
+
     fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
         let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
         let locator = self.excerpt_locator_for_id(excerpt_id);
@@ -4675,6 +4753,10 @@ impl<'a> MultiBufferExcerpt<'a> {
         self.excerpt_position
     }
 
+    pub fn end_point(&self) -> Point {
+        self.excerpt_position + self.excerpt.text_summary.lines
+    }
+
     /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
     pub fn map_offset_to_buffer(&self, offset: usize) -> usize {
         self.excerpt.buffer_start_offset()

crates/rope/src/rope.rs

@@ -989,6 +989,14 @@ impl TextSummary {
             column: self.last_line_len_utf16,
         }
     }
+
+    pub fn add_newline(&mut self) {
+        self.len += 1;
+        self.len_utf16 += OffsetUtf16(self.len_utf16.0 + 1);
+        self.last_line_chars = 0;
+        self.last_line_len_utf16 = 0;
+        self.lines += Point::new(1, 0);
+    }
 }
 
 impl<'a> From<&'a str> for TextSummary {

crates/text/src/patch.rs

@@ -42,6 +42,7 @@ where
         self.0
     }
 
+    #[must_use]
     pub fn compose(&self, new_edits_iter: impl IntoIterator<Item = Edit<T>>) -> Self {
         let mut old_edits_iter = self.0.iter().cloned().peekable();
         let mut new_edits_iter = new_edits_iter.into_iter().peekable();