WIP

crates/language/src/multi_buffer.rs

@@ -12,6 +12,7 @@ use clock::ReplicaId;
 use collections::HashMap;
 use gpui::{AppContext, Entity, ModelContext, ModelHandle, MutableAppContext, Task};
 use parking_lot::{Mutex, MutexGuard};
+use smallvec::SmallVec;
 use std::{cmp, io, ops::Range, sync::Arc, time::SystemTime};
 use sum_tree::{Bias, Cursor, SumTree};
 use text::{
@@ -31,6 +32,7 @@ pub struct MultiBuffer {
     snapshot: Mutex<MultiBufferSnapshot>,
     buffers: HashMap<usize, BufferState>,
     subscriptions: Topic,
+    selection_sets: HashMap<SelectionSetId, SelectionSet>,
 }
 
 pub trait ToOffset: 'static {
@@ -409,12 +411,30 @@ impl MultiBuffer {
         self.snapshot.lock().anchor_at(position, bias)
     }
 
-    pub fn anchor_range_set<E>(
+    pub fn anchor_range_map<T, E>(
         &self,
         start_bias: Bias,
         end_bias: Bias,
         entries: E,
-    ) -> AnchorRangeSet
+    ) -> AnchorRangeMap<T>
+    where
+        E: IntoIterator<Item = (Range<usize>, T)>,
+    {
+        let entries = entries.into_iter().peekable();
+        let mut child_maps = SmallVec::new();
+        if let Some((range, _)) = entries.peek() {
+            let mut cursor = self.snapshot.lock().excerpts.cursor::<ExcerptSummary>();
+            cursor.seek(&range.start, Bias::Right, &());
+            let mut excerpt_end = cursor.end(&());
+
+            // child_maps.push
+
+            // for entry in entries {}
+        }
+        AnchorRangeMap { child_maps }
+    }
+
+    pub fn anchor_range_set<E>(&self, start_bias: Bias, end_bias: Bias, ranges: E) -> AnchorRangeSet
     where
         E: IntoIterator<Item = Range<usize>>,
     {

crates/language/src/multi_buffer/anchor.rs

@@ -14,9 +14,9 @@ pub struct Anchor {
     text_anchor: text::Anchor,
 }
 
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, Default, PartialEq, Eq)]
 pub struct AnchorRangeMap<T> {
-    entries: SmallVec<[(ExcerptId, text::AnchorRangeMap<T>); 1]>,
+    pub(crate) child_maps: SmallVec<[(ExcerptId, text::AnchorRangeMap<T>); 1]>,
 }
 
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -99,7 +99,7 @@ impl Anchor {
 
 impl<T> AnchorRangeMap<T> {
     pub fn len(&self) -> usize {
-        self.entries
+        self.child_maps
             .iter()
             .map(|(_, text_map)| text_map.len())
             .sum()
@@ -113,7 +113,7 @@ impl<T> AnchorRangeMap<T> {
         D: TextDimension + Clone,
     {
         let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>();
-        self.entries
+        self.child_maps
             .iter()
             .filter_map(move |(excerpt_id, text_map)| {
                 cursor.seek_forward(excerpt_id, Bias::Left, &());
@@ -154,14 +154,14 @@ impl<T> AnchorRangeMap<T> {
         cursor.seek(&start_offset, start_bias, &());
         let start_excerpt_id = &cursor.start().excerpt_id;
         let start_ix = match self
-            .entries
+            .child_maps
             .binary_search_by_key(&start_excerpt_id, |e| &e.0)
         {
             Ok(ix) | Err(ix) => ix,
         };
 
         let mut entry_ranges = None;
-        let mut entries = self.entries[start_ix..].iter();
+        let mut entries = self.child_maps[start_ix..].iter();
         std::iter::from_fn(move || loop {
             match &mut entry_ranges {
                 None => {
@@ -265,7 +265,7 @@ impl<T> AnchorRangeMap<T> {
     {
         let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>();
         let mut max = None;
-        for (excerpt_id, text_map) in &self.entries {
+        for (excerpt_id, text_map) in &self.child_maps {
             cursor.seek(excerpt_id, Bias::Left, &());
             if let Some(excerpt) = cursor.item() {
                 if excerpt.id == *excerpt_id {