Perform initial file load git diff async

crates/language/src/buffer.rs

@@ -425,8 +425,6 @@ impl Buffer {
             UNIX_EPOCH
         };
 
-        let git_diff = smol::block_on(BufferDiff::new(head_text.clone(), &buffer));
-
         Self {
             saved_mtime,
             saved_version: buffer.version(),
@@ -435,7 +433,7 @@ impl Buffer {
             was_dirty_before_starting_transaction: None,
             text: buffer,
             head_text,
-            git_diff,
+            git_diff: BufferDiff::new(),
             file,
             syntax_map: Mutex::new(SyntaxMap::new()),
             parsing_in_background: false,
@@ -659,16 +657,18 @@ impl Buffer {
     }
 
     pub fn update_git(&mut self, cx: &mut ModelContext<Self>) {
-        if self.head_text.is_some() {
+        if let Some(head_text) = &self.head_text {
             let snapshot = self.snapshot();
-            let head_text = self.head_text.clone();
+            let head_text = head_text.clone();
 
-            let buffer_diff = cx
-                .background()
-                .spawn(async move { BufferDiff::new(head_text, &snapshot).await });
+            let mut diff = self.git_diff.clone();
+            let diff = cx.background().spawn(async move {
+                diff.update(&head_text, &snapshot).await;
+                diff
+            });
 
             cx.spawn_weak(|this, mut cx| async move {
-                let buffer_diff = buffer_diff.await;
+                let buffer_diff = diff.await;
                 if let Some(this) = this.upgrade(&cx) {
                     this.update(&mut cx, |this, cx| {
                         this.git_diff = buffer_diff;

crates/language/src/git.rs

@@ -1,4 +1,4 @@
-use std::{ops::Range, sync::Arc};
+use std::ops::Range;
 
 use sum_tree::SumTree;
 use text::{Anchor, BufferSnapshot, OffsetRangeExt, Point, ToPoint};
@@ -98,22 +98,16 @@ impl<'a> sum_tree::Dimension<'a, DiffHunkSummary> for HunkBufferEnd {
 
 #[derive(Clone)]
 pub struct BufferDiff {
-    last_buffer_version: clock::Global,
+    last_buffer_version: Option<clock::Global>,
     tree: SumTree<DiffHunk<Anchor>>,
 }
 
 impl BufferDiff {
-    pub async fn new(head_text: Option<Arc<String>>, buffer: &text::BufferSnapshot) -> BufferDiff {
-        let mut instance = BufferDiff {
-            last_buffer_version: buffer.version().clone(),
+    pub fn new() -> BufferDiff {
+        BufferDiff {
+            last_buffer_version: None,
             tree: SumTree::new(),
-        };
-
-        if let Some(head_text) = head_text {
-            instance.update(&*head_text, buffer);
         }
-
-        instance
     }
 
     pub fn hunks_in_range<'a>(
@@ -142,10 +136,13 @@ impl BufferDiff {
     }
 
     pub fn needs_update(&self, buffer: &text::BufferSnapshot) -> bool {
-        buffer.version().changed_since(&self.last_buffer_version)
+        match &self.last_buffer_version {
+            Some(last) => buffer.version().changed_since(last),
+            None => true,
+        }
     }
 
-    fn update(&mut self, head_text: &str, buffer: &text::BufferSnapshot) {
+    pub async fn update(&mut self, head_text: &str, buffer: &text::BufferSnapshot) {
         let mut tree = SumTree::new();
 
         let buffer_text = buffer.as_rope().to_string();
@@ -160,7 +157,7 @@ impl BufferDiff {
         }
 
         self.tree = tree;
-        self.last_buffer_version = buffer.version().clone();
+        self.last_buffer_version = Some(buffer.version().clone());
     }
 
     #[cfg(test)]
@@ -279,7 +276,8 @@ mod tests {
         .unindent();
 
         let mut buffer = Buffer::new(0, 0, buffer_text);
-        let diff = smol::block_on(BufferDiff::new(Some(Arc::new(head_text.clone())), &buffer));
+        let mut diff = BufferDiff::new();
+        smol::block_on(diff.update(&head_text, &buffer));
         assert_hunks(&diff, &buffer, &head_text, &[(1..2, "two\n")]);
 
         buffer.edit([(0..0, "point five\n")]);

crates/project/src/worktree.rs

@@ -449,7 +449,11 @@ impl LocalWorktree {
             let (file, contents, head_text) = this
                 .update(&mut cx, |t, cx| t.as_local().unwrap().load(&path, cx))
                 .await?;
-            Ok(cx.add_model(|cx| Buffer::from_file(0, contents, head_text, Arc::new(file), cx)))
+            Ok(cx.add_model(|cx| {
+                let mut buffer = Buffer::from_file(0, contents, head_text, Arc::new(file), cx);
+                buffer.update_git(cx);
+                buffer
+            }))
         })
     }