diff --git a/crates/editor/src/display_map.rs b/crates/editor/src/display_map.rs
index 596dc9507f..537c4f8ee8 100644
--- a/crates/editor/src/display_map.rs
+++ b/crates/editor/src/display_map.rs
@@ -1,4 +1,5 @@
 mod fold_map;
+mod injection_map;
 mod tab_map;
 mod wrap_map;
 
diff --git a/crates/editor/src/display_map/injection_map.rs b/crates/editor/src/display_map/injection_map.rs
new file mode 100644
index 0000000000..3bd142fe78
--- /dev/null
+++ b/crates/editor/src/display_map/injection_map.rs
@@ -0,0 +1,252 @@
+use std::{
+    cmp, mem,
+    sync::atomic::{AtomicUsize, Ordering::SeqCst},
+};
+
+use buffer::{Anchor, Bias, Edit, Point, Rope, TextSummary};
+use gpui::{fonts::HighlightStyle, AppContext, ModelHandle};
+use language::Buffer;
+use parking_lot::Mutex;
+use sum_tree::SumTree;
+
+#[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_contents: SumTree<InjectionContent>,
+    version: AtomicUsize,
+    last_sync: Mutex<SyncState>,
+}
+
+pub struct InjectionSnapshot {
+    transforms: SumTree<Transform>,
+    injection_contents: SumTree<InjectionContent>,
+    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 Injection {
+    id: InjectionId,
+    position: Anchor,
+    is_block: bool,
+}
+
+#[derive(Clone, Debug)]
+struct InjectionSummary {
+    min_id: InjectionId,
+    max_id: InjectionId,
+    min_position: Anchor,
+    max_position: Anchor,
+}
+
+#[derive(Clone, Debug)]
+struct InjectionContent {
+    injection_id: InjectionId,
+    runs: Vec<(usize, HighlightStyle)>,
+    text: Rope,
+}
+
+#[derive(Clone, Debug, Default, PartialEq)]
+struct Transform {
+    summary: TransformSummary,
+    injection_id: Option<InjectionId>,
+}
+
+#[derive(Clone, Debug, Default, Eq, PartialEq)]
+struct TransformSummary {
+    output: TextSummary,
+    input: TextSummary,
+}
+
+#[derive(Copy, Clone)]
+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 read(&self, cx: &AppContext) -> (InjectionSnapshot, Vec<Edit<InjectionOffset>>) {
+        let edits = self.sync(cx);
+        // self.check_invariants(cx);
+        let snapshot = InjectionSnapshot {
+            transforms: self.transforms.lock().clone(),
+            injection_contents: self.injection_contents.clone(),
+            buffer_snapshot: self.buffer.read(cx).snapshot(),
+            version: self.version.load(SeqCst),
+        };
+        (snapshot, edits)
+    }
+
+    pub fn write(
+        &mut self,
+        cx: &AppContext,
+    ) -> (
+        InjectionMapWriter,
+        InjectionSnapshot,
+        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<usize>>,
+        cx: &AppContext,
+    ) -> Vec<Edit<InjectionOffset>> {
+        let buffer = self.buffer.read(cx).snapshot();
+        let mut buffer_edits_iter = buffer_edits.iter().cloned().peekable();
+
+        let mut new_transforms = SumTree::<Transform>::new();
+        let mut transforms = self.transforms.lock();
+        let mut cursor = transforms.cursor::<usize>();
+
+        while let Some(mut edit) = buffer_edits_iter.next() {
+            new_transforms.push_tree(cursor.slice(&edit.old.start, Bias::Left, &()), &());
+            edit.new.start -= edit.old.start - cursor.start();
+            edit.old.start = *cursor.start();
+
+            cursor.seek(&edit.old.end, Bias::Right, &());
+            cursor.next(&());
+
+            let mut delta = edit.new.len() as isize - edit.old.len() as isize;
+            loop {
+                edit.old.end = *cursor.start();
+
+                if let Some(next_edit) = buffer_edits_iter.peek() {
+                    if next_edit.old.start > edit.old.end {
+                        break;
+                    }
+
+                    let next_edit = buffer_edits_iter.next().unwrap();
+                    delta += next_edit.new.len() as isize - next_edit.old.len() as isize;
+
+                    if next_edit.old.end >= edit.old.end {
+                        edit.old.end = next_edit.old.end;
+                        cursor.seek(&edit.old.end, Bias::Right, &());
+                        cursor.next(&());
+                    }
+                } else {
+                    break;
+                }
+            }
+
+            edit.new.end = ((edit.new.start + edit.old.len()) as isize + delta) as usize;
+
+            let anchor = buffer.anchor_before(edit.new.start);
+            let mut injections_cursor = self.injections.cursor::<Anchor>();
+            // folds_cursor.seek(&Fold(anchor..Anchor::max()), Bias::Left, &buffer);
+        }
+
+        todo!()
+    }
+}
+
+impl sum_tree::Item for Injection {
+    type Summary = InjectionSummary;
+
+    fn summary(&self) -> Self::Summary {
+        InjectionSummary {
+            min_id: self.id,
+            max_id: self.id,
+            min_position: self.position.clone(),
+            max_position: self.position.clone(),
+        }
+    }
+}
+
+impl sum_tree::Summary for InjectionSummary {
+    type Context = buffer::Snapshot;
+
+    fn add_summary(&mut self, summary: &Self, _: &buffer::Snapshot) {
+        self.max_position = summary.max_position.clone();
+        self.min_id = cmp::min(self.min_id, summary.min_id);
+        self.max_id = cmp::max(self.max_id, summary.max_id);
+    }
+}
+
+impl Default for InjectionSummary {
+    fn default() -> Self {
+        Self {
+            min_id: InjectionId(0),
+            max_id: InjectionId(usize::MAX),
+            min_position: Anchor::max(),
+            max_position: Anchor::min(),
+        }
+    }
+}
+
+impl sum_tree::Item for InjectionContent {
+    type Summary = InjectionId;
+
+    fn summary(&self) -> Self::Summary {
+        self.injection_id
+    }
+}
+
+impl sum_tree::Item for Transform {
+    type Summary = TransformSummary;
+
+    fn summary(&self) -> Self::Summary {
+        self.summary.clone()
+    }
+}
+
+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
+    }
+}