WIP

Antonio Scandurra and Nathan Sobo created

Co-Authored-By: Nathan Sobo <nathan@zed.dev>

Change summary

crates/editor/src/display_map.rs               |   3 
crates/editor/src/display_map/injection_map.rs | 586 --------------------
crates/editor/src/display_map/wrap_map.rs      | 104 +++
3 files changed, 91 insertions(+), 602 deletions(-)

Detailed changes

crates/editor/src/display_map.rs 🔗

@@ -1,6 +1,5 @@
 mod block_map;
 mod fold_map;
-mod injection_map;
 mod tab_map;
 mod wrap_map;
 
@@ -53,7 +52,7 @@ impl DisplayMap {
     pub fn snapshot(&self, cx: &mut ModelContext<Self>) -> DisplayMapSnapshot {
         let (folds_snapshot, edits) = self.fold_map.read(cx);
         let (tabs_snapshot, edits) = self.tab_map.sync(folds_snapshot.clone(), edits);
-        let wraps_snapshot = self
+        let (wraps_snapshot, _) = self
             .wrap_map
             .update(cx, |map, cx| map.sync(tabs_snapshot.clone(), edits, cx));
         DisplayMapSnapshot {

crates/editor/src/display_map/injection_map.rs 🔗

@@ -1,586 +0,0 @@
-use std::{
-    cmp::{self, Ordering},
-    collections::BTreeMap,
-    mem,
-    sync::atomic::{AtomicUsize, Ordering::SeqCst},
-};
-
-use buffer::{Anchor, Bias, Edit, Point, Rope, TextSummary, ToOffset, ToPoint};
-use gpui::{fonts::HighlightStyle, AppContext, ModelHandle};
-use language::Buffer;
-use parking_lot::Mutex;
-use sum_tree::SumTree;
-use util::post_inc;
-
-#[derive(Clone, Copy, Debug, Default, Eq, PartialEq, Ord, PartialOrd)]
-pub struct InjectionId(usize);
-
-pub struct InjectionMap {
-    buffer: ModelHandle<Buffer>,
-    transforms: Mutex<SumTree<Transform>>,
-    injections: SumTree<Injection>,
-    injection_sites: SumTree<InjectionSite>,
-    version: AtomicUsize,
-    last_sync: Mutex<SyncState>,
-    next_injection_id: usize,
-}
-
-pub struct Snapshot {
-    transforms: SumTree<Transform>,
-    injections: SumTree<Injection>,
-    buffer_snapshot: language::Snapshot,
-    pub version: usize,
-}
-
-pub struct InjectionMapWriter<'a>(&'a mut InjectionMap);
-
-#[derive(Clone)]
-struct SyncState {
-    version: clock::Global,
-    parse_count: usize,
-    diagnostics_update_count: usize,
-}
-
-#[derive(Clone, Debug)]
-struct InjectionSummary {
-    min_id: InjectionId,
-    max_id: InjectionId,
-    min_position: Anchor,
-    max_position: Anchor,
-}
-
-#[derive(Clone, Debug)]
-struct Injection {
-    id: InjectionId,
-    text: Rope,
-    runs: Vec<(usize, HighlightStyle)>,
-}
-
-#[derive(Clone, Debug)]
-pub struct InjectionProps {
-    text: Rope,
-    runs: Vec<(usize, HighlightStyle)>,
-    disposition: Disposition,
-}
-
-#[derive(Clone, Debug)]
-pub enum Disposition {
-    BeforeLine,
-    AfterLine,
-}
-
-#[derive(Clone, Debug)]
-struct InjectionSite {
-    injection_id: InjectionId,
-    position: Anchor,
-    disposition: Disposition,
-}
-
-#[derive(Clone, Debug)]
-struct InjectionSitePosition(Anchor);
-
-#[derive(Clone, Debug, Eq, PartialEq)]
-struct InjectionSiteSummary {
-    min_injection_id: InjectionId,
-    max_injection_id: InjectionId,
-    min_position: Anchor,
-    max_position: Anchor,
-}
-
-#[derive(Clone, Debug, Default, PartialEq)]
-struct Transform {
-    input: TextSummary,
-    output: TextSummary,
-    injection_id: Option<InjectionId>,
-}
-
-#[derive(Clone, Debug, Default, Eq, PartialEq)]
-struct TransformSummary {
-    input: TextSummary,
-    output: TextSummary,
-    min_injection_id: InjectionId,
-    max_injection_id: InjectionId,
-}
-
-#[derive(Copy, Clone, Debug, Default)]
-pub struct InjectionOffset(usize);
-
-impl sum_tree::Summary for InjectionId {
-    type Context = ();
-
-    fn add_summary(&mut self, summary: &Self, cx: &Self::Context) {
-        *self = *summary
-    }
-}
-
-impl InjectionMap {
-    pub fn new(buffer_handle: ModelHandle<Buffer>, cx: &AppContext) -> (Self, Snapshot) {
-        let buffer = buffer_handle.read(cx);
-        let this = Self {
-            buffer: buffer_handle,
-            injections: Default::default(),
-            injection_sites: Default::default(),
-            transforms: Mutex::new(SumTree::from_item(
-                Transform::isomorphic(buffer.text_summary()),
-                &(),
-            )),
-            last_sync: Mutex::new(SyncState {
-                version: buffer.version(),
-                parse_count: buffer.parse_count(),
-                diagnostics_update_count: buffer.diagnostics_update_count(),
-            }),
-            version: AtomicUsize::new(0),
-            next_injection_id: 0,
-        };
-        let (snapshot, _) = this.read(cx);
-        (this, snapshot)
-    }
-
-    pub fn read(&self, cx: &AppContext) -> (Snapshot, Vec<Edit<InjectionOffset>>) {
-        let edits = self.sync(cx);
-        // self.check_invariants(cx);
-        let snapshot = Snapshot {
-            transforms: self.transforms.lock().clone(),
-            injections: self.injections.clone(),
-            buffer_snapshot: self.buffer.read(cx).snapshot(),
-            version: self.version.load(SeqCst),
-        };
-        (snapshot, edits)
-    }
-
-    pub fn write(
-        &mut self,
-        cx: &AppContext,
-    ) -> (InjectionMapWriter, Snapshot, Vec<Edit<InjectionOffset>>) {
-        let (snapshot, edits) = self.read(cx);
-        (InjectionMapWriter(self), snapshot, edits)
-    }
-
-    fn sync(&self, cx: &AppContext) -> Vec<Edit<InjectionOffset>> {
-        let buffer = self.buffer.read(cx);
-        let last_sync = mem::replace(
-            &mut *self.last_sync.lock(),
-            SyncState {
-                version: buffer.version(),
-                parse_count: buffer.parse_count(),
-                diagnostics_update_count: buffer.diagnostics_update_count(),
-            },
-        );
-        let edits = buffer
-            .edits_since(&last_sync.version)
-            .map(Into::into)
-            .collect::<Vec<_>>();
-        if edits.is_empty() {
-            if last_sync.parse_count != buffer.parse_count()
-                || last_sync.diagnostics_update_count != buffer.diagnostics_update_count()
-            {
-                self.version.fetch_add(1, SeqCst);
-            }
-            Vec::new()
-        } else {
-            self.apply_edits(edits, cx)
-        }
-    }
-
-    fn apply_edits(
-        &self,
-        buffer_edits: Vec<buffer::Edit<Point>>,
-        cx: &AppContext,
-    ) -> Vec<Edit<InjectionOffset>> {
-        let buffer = self.buffer.read(cx);
-        let mut buffer_edits_iter = buffer_edits.iter().cloned().peekable();
-
-        let mut new_transforms = SumTree::<Transform>::new();
-        let mut transforms = self.transforms.lock();
-        let old_max_point = transforms.summary().input.lines;
-        let new_max_point = buffer.max_point();
-        let mut cursor = transforms.cursor::<Point>();
-        let mut injection_sites = self.injection_sites.cursor::<InjectionSitePosition>();
-        let mut pending_after_injections: Vec<InjectionId> = Vec::new();
-
-        while let Some(mut edit) = buffer_edits_iter.next() {
-            dbg!(&edit);
-            // Expand this edit to line boundaries.
-            edit.old.start.column = 0;
-            edit.old.end += Point::new(1, 0);
-            edit.new.start.column = 0;
-            edit.new.end += Point::new(1, 0);
-
-            // Push any transforms preceding the edit.
-            new_transforms.push_tree(cursor.slice(&edit.old.start, Bias::Left, &()), &());
-
-            // Snap edits to row boundaries of intersecting transforms.
-            loop {
-                if cmp::min(edit.old.end, old_max_point) <= cursor.end(&()) {
-                    cursor.seek(&edit.old.end, Bias::Left, &());
-                    cursor.next(&());
-                    let new_old_end = *cursor.start() + Point::new(1, 0);
-                    edit.new.end += new_old_end - edit.old.end;
-                    edit.old.end = new_old_end;
-                }
-
-                if buffer_edits_iter.peek().map_or(false, |next_edit| {
-                    edit.old.end.row >= next_edit.old.start.row
-                }) {
-                    let next_edit = buffer_edits_iter.next().unwrap();
-                    edit.old.end = cmp::max(edit.old.end, next_edit.old.end + Point::new(1, 0));
-                    let row_delta = (next_edit.new.end.row as i32 - next_edit.new.start.row as i32)
-                        - (next_edit.old.end.row as i32 - next_edit.old.start.row as i32);
-                    edit.new.end.row = (edit.new.end.row as i32 + row_delta) as u32;
-                } else {
-                    break;
-                }
-            }
-
-            dbg!(&edit);
-
-            // Find and insert all injections on the lines spanned by the edit, interleaved with isomorphic regions
-            injection_sites.seek(
-                &InjectionSitePosition(buffer.anchor_before(edit.new.start)),
-                Bias::Right,
-                buffer,
-            );
-            let mut last_injection_row: Option<u32> = None;
-            while let Some(site) = injection_sites.item() {
-                let injection_row = site.position.to_point(buffer).row;
-
-                if injection_row > edit.new.end.row {
-                    break;
-                }
-
-                // If we've moved on to a new injection row, ensure that any pending injections with an after
-                // disposition are inserted after their target row
-                if let Some(last_injection_row) = last_injection_row {
-                    if injection_row != last_injection_row {
-                        let injection_point = Point::new(last_injection_row + 1, 0);
-                        if injection_point > new_transforms.summary().input.lines {
-                            let injection_offset = injection_point.to_offset(buffer);
-                            new_transforms.push(
-                                Transform::isomorphic(buffer.text_summary_for_range(
-                                    new_transforms.summary().input.bytes..injection_offset,
-                                )),
-                                &(),
-                            );
-                        }
-                        for injection_id in pending_after_injections.drain(..) {
-                            new_transforms.push(
-                                Transform::for_injection(
-                                    self.injections.get(&injection_id, &()).unwrap(),
-                                ),
-                                &(),
-                            )
-                        }
-                    }
-                }
-
-                match site.disposition {
-                    Disposition::AfterLine => pending_after_injections.push(site.injection_id),
-                    Disposition::BeforeLine => {
-                        let injection_point = Point::new(injection_row, 0);
-                        if injection_point > new_transforms.summary().input.lines {
-                            let injection_offset = injection_point.to_offset(buffer);
-                            new_transforms.push(
-                                Transform::isomorphic(buffer.text_summary_for_range(
-                                    new_transforms.summary().input.bytes..injection_offset,
-                                )),
-                                &(),
-                            );
-                        }
-                        new_transforms.push(
-                            Transform::for_injection(
-                                self.injections.get(&site.injection_id, &()).unwrap(),
-                            ),
-                            &(),
-                        );
-                    }
-                }
-
-                last_injection_row = Some(injection_row);
-            }
-
-            if let Some(last_injection_row) = last_injection_row {
-                let injection_point = Point::new(last_injection_row + 1, 0);
-                if injection_point > new_transforms.summary().input.lines {
-                    let injection_offset = injection_point.to_offset(buffer);
-                    new_transforms.push(
-                        Transform::isomorphic(buffer.text_summary_for_range(
-                            new_transforms.summary().input.bytes..injection_offset,
-                        )),
-                        &(),
-                    );
-                }
-                for injection_id in pending_after_injections.drain(..) {
-                    new_transforms.push(
-                        Transform::for_injection(self.injections.get(&injection_id, &()).unwrap()),
-                        &(),
-                    )
-                }
-            }
-
-            let sum = new_transforms.summary();
-            let new_end = cmp::min(edit.new.end, new_max_point);
-            if sum.input.lines < new_end {
-                let text_summary =
-                    buffer.text_summary_for_range(sum.input.bytes..new_end.to_offset(buffer));
-                new_transforms.push(Transform::isomorphic(text_summary), &());
-            }
-        }
-        new_transforms.push_tree(cursor.suffix(&()), &());
-        drop(cursor);
-
-        *transforms = new_transforms;
-        Vec::new()
-    }
-}
-
-impl<'a> InjectionMapWriter<'a> {
-    pub fn insert<'b, T, U>(
-        &mut self,
-        injections: T,
-        cx: &AppContext,
-    ) -> (Vec<InjectionId>, Snapshot, Vec<Edit<InjectionOffset>>)
-    where
-        T: IntoIterator<Item = (Anchor, InjectionProps)>,
-    {
-        let buffer = self.0.buffer.read(cx);
-        let mut cursor = self.0.injection_sites.cursor::<InjectionSitePosition>();
-        let mut new_sites = SumTree::new();
-        let mut injection_ids = Vec::new();
-        let mut edits = Vec::new();
-
-        for (position, props) in injections {
-            let point = position.to_point(buffer);
-            edits.push(Edit {
-                old: point..point,
-                new: point..point,
-            });
-
-            let id = InjectionId(post_inc(&mut self.0.next_injection_id));
-            injection_ids.push(id);
-            new_sites.push_tree(
-                cursor.slice(
-                    &InjectionSitePosition(position.clone()),
-                    Bias::Right,
-                    buffer,
-                ),
-                buffer,
-            );
-            new_sites.push(
-                InjectionSite {
-                    injection_id: id,
-                    position,
-                    disposition: props.disposition,
-                },
-                buffer,
-            );
-            self.0.injections.push(
-                Injection {
-                    id,
-                    text: props.text,
-                    runs: props.runs,
-                },
-                &(),
-            );
-        }
-        new_sites.push_tree(cursor.suffix(buffer), buffer);
-
-        drop(cursor);
-        self.0.injection_sites = new_sites;
-
-        let edits = self.0.apply_edits(edits, cx);
-        let snapshot = Snapshot {
-            transforms: self.0.transforms.lock().clone(),
-            injections: self.0.injections.clone(),
-            buffer_snapshot: buffer.snapshot(),
-            version: self.0.version.load(SeqCst),
-        };
-
-        (injection_ids, snapshot, edits)
-    }
-}
-
-impl sum_tree::Item for Injection {
-    type Summary = InjectionId;
-
-    fn summary(&self) -> Self::Summary {
-        self.id
-    }
-}
-
-impl sum_tree::KeyedItem for Injection {
-    type Key = InjectionId;
-
-    fn key(&self) -> Self::Key {
-        self.id
-    }
-}
-
-impl sum_tree::Item for InjectionSite {
-    type Summary = InjectionSiteSummary;
-
-    fn summary(&self) -> Self::Summary {
-        InjectionSiteSummary {
-            min_injection_id: self.injection_id,
-            max_injection_id: self.injection_id,
-            min_position: self.position.clone(),
-            max_position: self.position.clone(),
-        }
-    }
-}
-
-impl Default for InjectionSitePosition {
-    fn default() -> Self {
-        Self(Anchor::min())
-    }
-}
-
-impl sum_tree::Summary for InjectionSiteSummary {
-    type Context = buffer::Buffer;
-
-    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
-        self.min_injection_id = cmp::min(self.min_injection_id, summary.min_injection_id);
-        self.max_injection_id = cmp::max(self.max_injection_id, summary.max_injection_id);
-        self.max_position = summary.max_position.clone();
-    }
-}
-
-impl<'a> sum_tree::Dimension<'a, InjectionSiteSummary> for InjectionSitePosition {
-    fn add_summary(&mut self, summary: &'a InjectionSiteSummary, _: &buffer::Buffer) {
-        self.0 = summary.max_position.clone();
-    }
-}
-
-impl<'a> sum_tree::SeekTarget<'a, InjectionSiteSummary, Self> for InjectionSitePosition {
-    fn cmp(&self, cursor_location: &Self, snapshot: &buffer::Buffer) -> Ordering {
-        self.0.cmp(&cursor_location.0, snapshot).unwrap()
-    }
-}
-
-impl Default for InjectionSiteSummary {
-    fn default() -> Self {
-        Self {
-            min_injection_id: InjectionId(usize::MAX),
-            max_injection_id: InjectionId(0),
-            min_position: Anchor::max(),
-            max_position: Anchor::min(),
-        }
-    }
-}
-
-impl Transform {
-    fn isomorphic(text_summary: TextSummary) -> Self {
-        Self {
-            input: text_summary.clone(),
-            output: text_summary,
-            injection_id: None,
-        }
-    }
-
-    fn for_injection(injection: &Injection) -> Self {
-        Self {
-            input: Default::default(),
-            output: injection.text.summary(),
-            injection_id: Some(injection.id),
-        }
-    }
-}
-
-impl sum_tree::Item for Transform {
-    type Summary = TransformSummary;
-
-    fn summary(&self) -> Self::Summary {
-        let min_injection_id;
-        let max_injection_id;
-        if let Some(id) = self.injection_id {
-            min_injection_id = id;
-            max_injection_id = id;
-        } else {
-            min_injection_id = InjectionId(usize::MAX);
-            max_injection_id = InjectionId(0);
-        }
-
-        TransformSummary {
-            input: self.input.clone(),
-            output: self.output.clone(),
-            min_injection_id,
-            max_injection_id,
-        }
-    }
-}
-
-impl sum_tree::Summary for TransformSummary {
-    type Context = ();
-
-    fn add_summary(&mut self, other: &Self, _: &()) {
-        self.input += &other.input;
-        self.output += &other.output;
-    }
-}
-
-impl<'a> sum_tree::Dimension<'a, TransformSummary> for usize {
-    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
-        *self += summary.input.bytes
-    }
-}
-
-impl<'a> sum_tree::Dimension<'a, TransformSummary> for Point {
-    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
-        *self += summary.input.lines
-    }
-}
-
-impl<'a> sum_tree::Dimension<'a, TransformSummary> for InjectionOffset {
-    fn add_summary(&mut self, summary: &'a TransformSummary, _: &()) {
-        self.0 += summary.output.bytes
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use std::env;
-
-    use super::*;
-    use buffer::RandomCharIter;
-    use rand::prelude::*;
-
-    #[gpui::test(iterations = 1000)]
-    fn test_random(cx: &mut gpui::MutableAppContext, mut rng: StdRng) {
-        let operations = env::var("OPERATIONS")
-            .map(|i| i.parse().expect("invalid `OPERATIONS` variable"))
-            .unwrap_or(1);
-
-        let buffer = cx.add_model(|cx| {
-            let len = rng.gen_range(0..10);
-            let text = RandomCharIter::new(&mut rng).take(len).collect::<String>();
-            Buffer::new(0, text, cx)
-        });
-        let (map, initial_snapshot) = InjectionMap::new(buffer.clone(), cx.as_ref());
-        assert_eq!(
-            initial_snapshot.transforms.summary().input,
-            buffer.read(cx).text_summary()
-        );
-
-        for _ in 0..operations {
-            log::info!("text: {:?}", buffer.read(cx).text());
-            match rng.gen_range(0..=100) {
-                _ => {
-                    let edits = buffer.update(cx, |buffer, _| {
-                        let start_version = buffer.version.clone();
-                        let edit_count = rng.gen_range(1..=5);
-                        buffer.randomly_edit(&mut rng, edit_count);
-                        buffer
-                            .edits_since::<Point>(&start_version)
-                            .collect::<Vec<_>>()
-                    });
-                    log::info!("editing {:?}", edits);
-                }
-            }
-
-            let (snapshot, edits) = map.read(cx.as_ref());
-            assert_eq!(
-                snapshot.transforms.summary().input,
-                buffer.read(cx).text_summary()
-            );
-        }
-    }
-}

crates/editor/src/display_map/wrap_map.rs 🔗

@@ -6,7 +6,7 @@ use gpui::{fonts::FontId, text_layout::LineWrapper, Entity, ModelContext, Task};
 use language::{HighlightedChunk, Point};
 use lazy_static::lazy_static;
 use smol::future::yield_now;
-use std::{collections::VecDeque, ops::Range, time::Duration};
+use std::{collections::VecDeque, mem, ops::Range, time::Duration};
 use sum_tree::{Bias, Cursor, SumTree};
 
 pub type Edit = buffer::Edit<u32>;
@@ -14,11 +14,16 @@ pub type Edit = buffer::Edit<u32>;
 pub struct WrapMap {
     snapshot: Snapshot,
     pending_edits: VecDeque<(TabSnapshot, Vec<TabEdit>)>,
+    interpolated_edits: Patch,
+    edits_since_sync: Patch,
     wrap_width: Option<f32>,
     background_task: Option<Task<()>>,
     font: (FontId, f32),
 }
 
+#[derive(Default)]
+struct Patch(Vec<Edit>);
+
 impl Entity for WrapMap {
     type Event = ();
 }
@@ -81,6 +86,8 @@ impl WrapMap {
             font: (font_id, font_size),
             wrap_width: None,
             pending_edits: Default::default(),
+            interpolated_edits: Default::default(),
+            edits_since_sync: Default::default(),
             snapshot: Snapshot::new(tab_snapshot),
             background_task: None,
         };
@@ -99,10 +106,13 @@ impl WrapMap {
         tab_snapshot: TabSnapshot,
         edits: Vec<TabEdit>,
         cx: &mut ModelContext<Self>,
-    ) -> Snapshot {
+    ) -> (Snapshot, Vec<Edit>) {
         self.pending_edits.push_back((tab_snapshot, edits));
         self.flush_edits(cx);
-        self.snapshot.clone()
+        (
+            self.snapshot.clone(),
+            mem::take(&mut self.edits_since_sync).0,
+        )
     }
 
     pub fn set_font(&mut self, font_id: FontId, font_size: f32, cx: &mut ModelContext<Self>) {
@@ -204,26 +214,32 @@ impl WrapMap {
                 let update_task = cx.background().spawn(async move {
                     let mut line_wrapper = font_cache.line_wrapper(font_id, font_size);
 
+                    let mut output_edits = Patch::default();
                     for (tab_snapshot, edits) in pending_edits {
-                        snapshot
+                        let wrap_edits = snapshot
                             .update(tab_snapshot, &edits, wrap_width, &mut line_wrapper)
                             .await;
+                        output_edits.compose(&wrap_edits);
                     }
-                    snapshot
+                    (snapshot, output_edits)
                 });
 
                 match cx
                     .background()
                     .block_with_timeout(Duration::from_millis(1), update_task)
                 {
-                    Ok(snapshot) => {
+                    Ok((snapshot, output_edits)) => {
                         self.snapshot = snapshot;
+                        self.edits_since_sync.compose(&output_edits);
                     }
                     Err(update_task) => {
                         self.background_task = Some(cx.spawn(|this, mut cx| async move {
-                            let snapshot = update_task.await;
+                            let (snapshot, output_edits) = update_task.await;
                             this.update(&mut cx, |this, cx| {
                                 this.snapshot = snapshot;
+                                this.edits_since_sync
+                                    .compose(mem::take(&mut this.interpolated_edits).invert())
+                                    .compose(&output_edits);
                                 this.background_task = None;
                                 this.flush_edits(cx);
                                 cx.notify();
@@ -240,7 +256,9 @@ impl WrapMap {
             if tab_snapshot.version() <= self.snapshot.tab_snapshot.version() {
                 to_remove_len += 1;
             } else {
-                self.snapshot.interpolate(tab_snapshot.clone(), &edits);
+                let interpolated_edits = self.snapshot.interpolate(tab_snapshot.clone(), &edits);
+                self.edits_since_sync.compose(&interpolated_edits);
+                self.interpolated_edits.compose(&interpolated_edits);
             }
         }
 
@@ -250,6 +268,59 @@ impl WrapMap {
     }
 }
 
+impl Patch {
+    fn compose(&mut self, other: &Self) -> &mut Self {
+
+        // let mut other_ranges = edit.ranges.iter().peekable();
+        // let mut new_ranges = Vec::new();
+        // let insertion_len = edit.new_text.as_ref().map_or(0, |t| t.len());
+        // let mut delta = 0;
+
+        // for mut self_range in self.ranges.iter().cloned() {
+        //     self_range.start += delta;
+        //     self_range.end += delta;
+
+        //     while let Some(other_range) = other_ranges.peek() {
+        //         let mut other_range = (*other_range).clone();
+        //         other_range.start += delta;
+        //         other_range.end += delta;
+
+        //         if other_range.start <= self_range.end {
+        //             other_ranges.next().unwrap();
+        //             delta += insertion_len;
+
+        //             if other_range.end < self_range.start {
+        //                 new_ranges.push(other_range.start..other_range.end + insertion_len);
+        //                 self_range.start += insertion_len;
+        //                 self_range.end += insertion_len;
+        //             } else {
+        //                 self_range.start = cmp::min(self_range.start, other_range.start);
+        //                 self_range.end = cmp::max(self_range.end, other_range.end) + insertion_len;
+        //             }
+        //         } else {
+        //             break;
+        //         }
+        //     }
+
+        //     new_ranges.push(self_range);
+        // }
+
+        // for other_range in other_ranges {
+        //     new_ranges.push(other_range.start + delta..other_range.end + delta + insertion_len);
+        //     delta += insertion_len;
+        // }
+
+        // self.ranges = new_ranges;
+    }
+
+    fn invert(&mut self) -> &mut Self {
+        for edit in &mut self.0 {
+            mem::swap(&mut edit.old, &mut edit.new);
+        }
+        self
+    }
+}
+
 impl Snapshot {
     fn new(tab_snapshot: TabSnapshot) -> Self {
         let mut transforms = SumTree::new();
@@ -264,7 +335,7 @@ impl Snapshot {
         }
     }
 
-    fn interpolate(&mut self, new_tab_snapshot: TabSnapshot, edits: &[TabEdit]) {
+    fn interpolate(&mut self, new_tab_snapshot: TabSnapshot, edits: &[TabEdit]) -> Patch {
         let mut new_transforms;
         if edits.is_empty() {
             new_transforms = self.transforms.clone();
@@ -320,6 +391,7 @@ impl Snapshot {
         self.tab_snapshot = new_tab_snapshot;
         self.interpolated = true;
         self.check_invariants();
+        todo!()
     }
 
     async fn update(
@@ -328,7 +400,7 @@ impl Snapshot {
         edits: &[TabEdit],
         wrap_width: f32,
         line_wrapper: &mut LineWrapper,
-    ) {
+    ) -> Patch {
         #[derive(Debug)]
         struct RowEdit {
             old_rows: Range<u32>,
@@ -458,6 +530,7 @@ impl Snapshot {
         self.tab_snapshot = new_tab_snapshot;
         self.interpolated = false;
         self.check_invariants();
+        todo!()
     }
 
     pub fn chunks_at(&self, wrap_row: u32) -> Chunks {
@@ -896,6 +969,8 @@ impl<'a> sum_tree::Dimension<'a, TransformSummary> for WrapPoint {
     }
 }
 
+fn compose(prev: &mut Vec<Edit>, next: &[Edit]) {}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -962,7 +1037,8 @@ mod tests {
             notifications.recv().await.unwrap();
         }
 
-        let snapshot = wrap_map.update(&mut cx, |map, cx| map.sync(tabs_snapshot, Vec::new(), cx));
+        let (snapshot, _) =
+            wrap_map.update(&mut cx, |map, cx| map.sync(tabs_snapshot, Vec::new(), cx));
         let actual_text = snapshot.text();
         assert_eq!(
             actual_text, expected_text,
@@ -987,7 +1063,7 @@ mod tests {
                         cx.read(|cx| fold_map.randomly_mutate(&mut rng, cx))
                     {
                         let (tabs_snapshot, edits) = tab_map.sync(folds_snapshot, edits);
-                        let mut snapshot =
+                        let (mut snapshot, _) =
                             wrap_map.update(&mut cx, |map, cx| map.sync(tabs_snapshot, edits, cx));
                         snapshot.check_invariants();
                         snapshot.verify_chunks(&mut rng);
@@ -1012,7 +1088,7 @@ mod tests {
 
             let unwrapped_text = tabs_snapshot.text();
             let expected_text = wrap_text(&unwrapped_text, wrap_width, &mut line_wrapper);
-            let mut snapshot = wrap_map.update(&mut cx, |map, cx| {
+            let (mut snapshot, _) = wrap_map.update(&mut cx, |map, cx| {
                 map.sync(tabs_snapshot.clone(), edits, cx)
             });
             snapshot.check_invariants();
@@ -1026,7 +1102,7 @@ mod tests {
             }
 
             if !wrap_map.read_with(&cx, |map, _| map.is_rewrapping()) {
-                let mut wrapped_snapshot =
+                let (mut wrapped_snapshot, _) =
                     wrap_map.update(&mut cx, |map, cx| map.sync(tabs_snapshot, Vec::new(), cx));
                 let actual_text = wrapped_snapshot.text();
                 log::info!("Wrapping finished: {:?}", actual_text);