perf: cache file attribution for instant blame navigation

src/editor.rs

@@ -1561,13 +1561,19 @@ impl Buffer {
     }
 
     fn refresh_file(&mut self) -> io::Result<bool> {
-        if self.diff_snapshot.is_some() || self.dirty() {
+        if self.diff_snapshot.is_some() {
             return Ok(false);
         }
         let Some(path) = &self.path else {
             return Ok(false);
         };
         let stamp = FileStamp::read(path)?;
+        if self.dirty() {
+            if stamp.is_none() && self.disk_stamp.is_some() {
+                return Err(io::Error::new(io::ErrorKind::NotFound, "File was removed"));
+            }
+            return Ok(false);
+        }
         if stamp == self.disk_stamp {
             return Ok(false);
         }
@@ -1670,8 +1676,10 @@ struct PendingLspNavigation {
 pub(crate) struct BlameSource {
     buffer: usize,
     revision: u64,
-    pub(crate) path: PathBuf,
+    pub(crate) path: Arc<Path>,
     pub(crate) row: usize,
+    save_revision: u64,
+    disk_stamp: Option<FileStamp>,
     pane: usize,
     tab: usize,
 }
@@ -1712,7 +1720,7 @@ pub struct Editor {
     battery_charge: Option<u8>,
     battery_label: String,
     git_blame: bool,
-    line_blame: Option<(BlameSource, String)>,
+    line_blame: Option<(BlameSource, Arc<crate::blame::LineBlame>, String)>,
     lsp_names: Vec<String>,
     lsp_label: String,
     quit: bool,
@@ -4682,27 +4690,37 @@ impl Editor {
             || self.should_quit()
             || self.diff.is_some()
             || self.active.diff_snapshot.is_some()
+            || self.active.reload_error.is_some()
         {
             return None;
         }
         Some(BlameSource {
             buffer: self.buffer_id(),
             revision: self.text_revision(),
-            path: self.path()?.to_owned(),
+            path: Arc::from(self.path()?),
             row: self.cursor().row,
+            save_revision: self.active.save_revision,
+            disk_stamp: self.active.disk_stamp,
             pane: self.pane_id(),
             tab: self.tab_id(),
         })
     }
 
-    pub(crate) fn blame_source_is_current(&self, source: &BlameSource) -> bool {
+    pub(crate) fn blame_file_source_is_current(&self, source: &BlameSource) -> bool {
         self.git_blame
             && !self.should_quit()
             && self.diff.is_none()
             && self.active.diff_snapshot.is_none()
+            && self.active.reload_error.is_none()
             && source.buffer == self.buffer_id()
             && source.revision == self.text_revision()
-            && Some(source.path.as_path()) == self.path()
+            && source.save_revision == self.active.save_revision
+            && source.disk_stamp == self.active.disk_stamp
+            && Some(source.path.as_ref()) == self.path()
+    }
+
+    pub(crate) fn blame_source_is_current(&self, source: &BlameSource) -> bool {
+        self.blame_file_source_is_current(source)
             && source.row == self.cursor().row
             && source.pane == self.pane_id()
             && source.tab == self.tab_id()
@@ -4712,14 +4730,32 @@ impl Editor {
         self.line_blame.take().is_some()
     }
 
+    pub(crate) fn set_cached_line_blame(
+        &mut self,
+        source: &BlameSource,
+        blame: Arc<crate::blame::LineBlame>,
+    ) -> bool {
+        let mut source = source.clone();
+        source.row = self.cursor().row;
+        source.pane = self.pane_id();
+        source.tab = self.tab_id();
+        self.set_line_blame(source, blame)
+    }
+
     pub(crate) fn set_line_blame(
         &mut self,
         source: BlameSource,
-        blame: crate::blame::LineBlame,
+        blame: Arc<crate::blame::LineBlame>,
     ) -> bool {
         if !self.blame_source_is_current(&source) {
             return false;
         }
+        if let Some((previous, metadata, _)) = &mut self.line_blame
+            && Arc::ptr_eq(metadata, &blame)
+        {
+            *previous = source;
+            return false;
+        }
         let label = if blame.uncommitted {
             "Uncommitted".to_owned()
         } else {
@@ -4728,15 +4764,19 @@ impl Editor {
                 blame.author, blame.summary, blame.commit
             ))
         };
-        self.line_blame = Some((source, label));
-        true
+        let changed = self
+            .line_blame
+            .as_ref()
+            .is_none_or(|(_, _, previous)| previous != &label);
+        self.line_blame = Some((source, blame, label));
+        changed
     }
 
     pub(crate) fn line_blame(&self) -> Option<&str> {
         self.line_blame
             .as_ref()
-            .filter(|(source, _)| self.blame_source_is_current(source))
-            .map(|(_, label)| label.as_str())
+            .filter(|(source, _, _)| self.blame_source_is_current(source))
+            .map(|(_, _, label)| label.as_str())
     }
     pub fn lsp_names(&self) -> &[String] {
         &self.lsp_names