Revert "Implement MultiBuffer::remove_excerpts by inserting tombstones"

This reverts commit 275b7e8d4f.

crates/editor/src/multi_buffer.rs

@@ -6,8 +6,8 @@ use clock::ReplicaId;
 use collections::{HashMap, HashSet};
 use gpui::{AppContext, Entity, ModelContext, ModelHandle, Task};
 use language::{
-    Buffer, BufferChunks, BufferSnapshot, Chunk, DiagnosticEntry, Event, File, Language, Patch,
+    Buffer, BufferChunks, BufferSnapshot, Chunk, DiagnosticEntry, Event, File, Language, Selection,
-    Selection, ToOffset as _, ToPoint as _, TransactionId,
+    ToOffset as _, ToPoint as _, TransactionId,
 };
 use std::{
     cell::{Ref, RefCell},
@@ -100,7 +100,6 @@ struct Excerpt {
     max_buffer_row: u32,
     text_summary: TextSummary,
     has_trailing_newline: bool,
-    is_tombstone: bool,
 }
 
 #[derive(Clone, Debug, Default)]
@@ -108,12 +107,8 @@ struct ExcerptSummary {
     excerpt_id: ExcerptId,
     max_buffer_row: u32,
     text: TextSummary,
-    visible_excerpts: usize,
 }
 
-#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, PartialOrd, Ord)]
-struct VisibleExcerptCount(usize);
-
 pub struct MultiBufferRows<'a> {
     buffer_row_range: Range<u32>,
     excerpts: Cursor<'a, Excerpt, Point>,
@@ -608,25 +603,16 @@ impl MultiBuffer {
         let range = buffer_snapshot.anchor_before(&props.range.start)
             ..buffer_snapshot.anchor_after(&props.range.end);
         let mut snapshot = self.snapshot.borrow_mut();
+        let mut prev_id = None;
         let edit_start = snapshot.excerpts.summary().text.bytes;
+        snapshot.excerpts.update_last(
+            |excerpt| {
+                excerpt.has_trailing_newline = true;
+                prev_id = Some(excerpt.id.clone());
+            },
+            &(),
+        );
 
-        snapshot.excerpts = {
-            let mut cursor = snapshot.excerpts.cursor::<VisibleExcerptCount>();
-            let mut new_excerpts = cursor.slice(
-                &VisibleExcerptCount(snapshot.excerpts.summary().visible_excerpts),
-                Bias::Left,
-                &(),
-            );
-            if let Some(mut excerpt) = cursor.item().cloned() {
-                excerpt.has_trailing_newline = !excerpt.is_tombstone;
-                new_excerpts.push(excerpt, &());
-                cursor.next(&());
-            }
-            new_excerpts.push_tree(cursor.suffix(&()), &());
-            new_excerpts
-        };
-
-        let prev_id = snapshot.excerpts.last().map(|e| e.id.clone());
         let id = ExcerptId::between(&prev_id.unwrap_or(ExcerptId::min()), &ExcerptId::max());
         self.buffers
             .borrow_mut()
@@ -669,60 +655,39 @@ impl MultiBuffer {
     ) {
         let mut buffers = self.buffers.borrow_mut();
         let mut snapshot = self.snapshot.borrow_mut();
-        let mut edits = Patch::default();
+        let mut new_excerpts = SumTree::new();
-        snapshot.excerpts = {
+        let mut cursor = snapshot.excerpts.cursor::<(Option<&ExcerptId>, usize)>();
-            let mut new_excerpts = SumTree::new();
+        let mut edits = Vec::new();
-            let mut cursor = snapshot.excerpts.cursor::<(Option<&ExcerptId>, usize)>();
+        for excerpt_id in excerpt_ids {
-            for excerpt_id in excerpt_ids {
+            new_excerpts.push_tree(cursor.slice(&Some(excerpt_id), Bias::Left, &()), &());
-                new_excerpts.push_tree(cursor.slice(&Some(excerpt_id), Bias::Left, &()), &());
+            if let Some(excerpt) = cursor.item() {
-                if let Some(excerpt) = cursor.item() {
+                if excerpt.id == *excerpt_id {
-                    if excerpt.id == *excerpt_id {
+                    let mut old_start = cursor.start().1;
-                        let old_start = cursor.start().1;
-                        let old_end = cursor.end(&()).1;
-                        cursor.next(&());
-
-                        if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
-                            buffer_state.excerpts.retain(|id| id != excerpt_id);
-                        }
-
-                        new_excerpts.push(excerpt.tombstone(), &());
-                        let new_start = new_excerpts.summary().text.bytes;
-                        edits.push(Edit {
-                            old: old_start..old_end,
-                            new: new_start..new_start,
-                        });
-                    }
-                }
-            }
-            new_excerpts.push_tree(cursor.suffix(&()), &());
-            new_excerpts
-        };
-
-        // Ensure there's no trailing newline on the last visible excerpt.
-        snapshot.excerpts = {
-            let mut cursor = snapshot.excerpts.cursor::<(VisibleExcerptCount, usize)>();
-            let mut new_excerpts = cursor.slice(
-                &VisibleExcerptCount(snapshot.excerpts.summary().visible_excerpts),
-                Bias::Left,
-                &(),
-            );
-            if let Some(mut excerpt) = cursor.item().cloned() {
-                if excerpt.has_trailing_newline {
-                    let old_start = cursor.start().1;
                     let old_end = cursor.end(&()).1;
-                    edits = edits.compose([Edit {
+                    cursor.next(&());
-                        old: old_start..old_end,
-                        new: old_start..old_end - 1,
-                    }]);
-                }
-                excerpt.has_trailing_newline = false;
-                new_excerpts.push(excerpt, &());
-                cursor.next(&());
-            }
-            new_excerpts.push_tree(cursor.suffix(&()), &());
-            new_excerpts
-        };
 
+                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
+                        buffer_state.excerpts.retain(|id| id != excerpt_id);
+                    }
+
+                    // When removing the last excerpt, remove the trailing newline from
+                    // the previous excerpt.
+                    if cursor.item().is_none() && old_start > 0 {
+                        old_start -= 1;
+                        new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
+                    }
+
+                    let new_start = new_excerpts.summary().text.bytes;
+                    edits.push(Edit {
+                        old: old_start..old_end,
+                        new: new_start..new_start,
+                    });
+                }
+            }
+        }
+        new_excerpts.push_tree(cursor.suffix(&()), &());
+        drop(cursor);
+        snapshot.excerpts = new_excerpts;
         self.subscriptions.publish_mut(edits);
         cx.notify();
     }
@@ -923,10 +888,6 @@ impl MultiBufferSnapshot {
         iter::from_fn(move || {
             if offset == *cursor.start() {
                 cursor.prev(&());
-                while cursor.item()?.is_tombstone {
-                    cursor.prev(&());
-                }
-
                 let excerpt = cursor.item()?;
                 excerpt_chunks = Some(
                     excerpt
@@ -1677,7 +1638,7 @@ impl Excerpt {
         range: Range<text::Anchor>,
         has_trailing_newline: bool,
     ) -> Self {
-        Self {
+        Excerpt {
             id,
             max_buffer_row: range.end.to_point(&buffer).row,
             text_summary: buffer.text_summary_for_range::<TextSummary, _>(range.to_offset(&buffer)),
@@ -1685,20 +1646,6 @@ impl Excerpt {
             buffer,
             range,
             has_trailing_newline,
-            is_tombstone: false,
-        }
-    }
-
-    fn tombstone(&self) -> Self {
-        Self {
-            id: self.id.clone(),
-            buffer_id: self.buffer_id,
-            buffer: self.buffer.clone(),
-            range: self.range.start.clone()..self.range.start.clone(),
-            max_buffer_row: 0,
-            text_summary: Default::default(),
-            has_trailing_newline: false,
-            is_tombstone: true,
         }
     }
 
@@ -1775,7 +1722,6 @@ impl fmt::Debug for Excerpt {
             .field("range", &self.range)
             .field("text_summary", &self.text_summary)
             .field("has_trailing_newline", &self.has_trailing_newline)
-            .field("is_tombstone", &self.is_tombstone)
             .finish()
     }
 }
@@ -1792,7 +1738,6 @@ impl sum_tree::Item for Excerpt {
             excerpt_id: self.id.clone(),
             max_buffer_row: self.max_buffer_row,
             text,
-            visible_excerpts: if self.is_tombstone { 0 } else { 1 },
         }
     }
 }
@@ -1805,7 +1750,6 @@ impl sum_tree::Summary for ExcerptSummary {
         self.excerpt_id = summary.excerpt_id.clone();
         self.text.add_summary(&summary.text, &());
         self.max_buffer_row = cmp::max(self.max_buffer_row, summary.max_buffer_row);
-        self.visible_excerpts += summary.visible_excerpts;
     }
 }
 
@@ -1851,12 +1795,6 @@ impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a ExcerptId> {
     }
 }
 
-impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for VisibleExcerptCount {
-    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
-        self.0 += summary.visible_excerpts;
-    }
-}
-
 impl<'a> MultiBufferRows<'a> {
     pub fn seek(&mut self, row: u32) {
         self.buffer_row_range = 0..0;
@@ -1865,13 +1803,6 @@ impl<'a> MultiBufferRows<'a> {
             .seek_forward(&Point::new(row, 0), Bias::Right, &());
         if self.excerpts.item().is_none() {
             self.excerpts.prev(&());
-            while let Some(excerpt) = self.excerpts.item() {
-                if excerpt.is_tombstone {
-                    self.excerpts.prev(&());
-                } else {
-                    break;
-                }
-            }
 
             if self.excerpts.item().is_none() && row == 0 {
                 self.buffer_row_range = 0..1;
@@ -1901,11 +1832,9 @@ impl<'a> Iterator for MultiBufferRows<'a> {
             self.excerpts.item()?;
             self.excerpts.next(&());
             let excerpt = self.excerpts.item()?;
-            if !excerpt.is_tombstone {
+            self.buffer_row_range.start = excerpt.range.start.to_point(&excerpt.buffer).row;
-                self.buffer_row_range.start = excerpt.range.start.to_point(&excerpt.buffer).row;
+            self.buffer_row_range.end =
-                self.buffer_row_range.end =
+                self.buffer_row_range.start + excerpt.text_summary.lines.row + 1;
-                    self.buffer_row_range.start + excerpt.text_summary.lines.row + 1;
-            }
         }
     }
 }
@@ -1940,9 +1869,6 @@ impl<'a> Iterator for MultiBufferChunks<'a> {
             Some(chunk)
         } else {
             self.excerpts.next(&());
-            while self.excerpts.item()?.is_tombstone {
-                self.excerpts.next(&());
-            }
             let excerpt = self.excerpts.item()?;
             self.excerpt_chunks = Some(
                 excerpt.chunks_in_range(0..self.range.end - self.excerpts.start(), self.theme),
@@ -1962,14 +1888,6 @@ impl<'a> MultiBufferBytes<'a> {
                 self.chunk = chunk;
             } else {
                 self.excerpts.next(&());
-                while let Some(excerpt) = self.excerpts.item() {
-                    if excerpt.is_tombstone {
-                        self.excerpts.next(&());
-                    } else {
-                        break;
-                    }
-                }
-
                 if let Some(excerpt) = self.excerpts.item() {
                     let mut excerpt_bytes =
                         excerpt.bytes_in_range(0..self.range.end - self.excerpts.start());