zeta2: Build edit prediction prompt and process model output in client (#41870)

Release Notes:

- N/A

---------

Co-authored-by: Agus Zubiaga <agus@zed.dev>
Co-authored-by: Ben Kunkle <ben@zed.dev>
Co-authored-by: Piotr Osiewicz <24362066+osiewicz@users.noreply.github.com>

crates/language/src/buffer.rs

@@ -720,7 +720,7 @@ impl EditPreview {
     pub fn highlight_edits(
         &self,
         current_snapshot: &BufferSnapshot,
-        edits: &[(Range<Anchor>, String)],
+        edits: &[(Range<Anchor>, impl AsRef<str>)],
         include_deletions: bool,
         cx: &App,
     ) -> HighlightedText {
@@ -747,7 +747,8 @@ impl EditPreview {
                 .end
                 .bias_right(&self.old_snapshot)
                 .to_offset(&self.applied_edits_snapshot);
-            let edit_start_in_preview_snapshot = edit_new_end_in_preview_snapshot - edit_text.len();
+            let edit_start_in_preview_snapshot =
+                edit_new_end_in_preview_snapshot - edit_text.as_ref().len();
 
             let unchanged_range_in_preview_snapshot =
                 offset_in_preview_snapshot..edit_start_in_preview_snapshot;
@@ -772,7 +773,7 @@ impl EditPreview {
                 );
             }
 
-            if !edit_text.is_empty() {
+            if !edit_text.as_ref().is_empty() {
                 highlighted_text.add_text_from_buffer_range(
                     edit_start_in_preview_snapshot..edit_new_end_in_preview_snapshot,
                     &self.applied_edits_snapshot,
@@ -796,7 +797,7 @@ impl EditPreview {
         highlighted_text.build()
     }
 
-    fn compute_visible_range(&self, edits: &[(Range<Anchor>, String)]) -> Option<Range<usize>> {
+    fn compute_visible_range<T>(&self, edits: &[(Range<Anchor>, T)]) -> Option<Range<usize>> {
         let (first, _) = edits.first()?;
         let (last, _) = edits.last()?;
 
@@ -1130,7 +1131,7 @@ impl Buffer {
 
     pub fn preview_edits(
         &self,
-        edits: Arc<[(Range<Anchor>, String)]>,
+        edits: Arc<[(Range<Anchor>, Arc<str>)]>,
         cx: &App,
     ) -> Task<EditPreview> {
         let registry = self.language_registry();

crates/language/src/buffer_tests.rs

@@ -3120,15 +3120,13 @@ async fn test_preview_edits(cx: &mut TestAppContext) {
                 .map(|(range, text)| {
                     (
                         buffer.anchor_before(range.start)..buffer.anchor_after(range.end),
-                        text.to_string(),
+                        text.into(),
                     )
                 })
-                .collect::<Vec<_>>()
+                .collect::<Arc<[_]>>()
         });
         let edit_preview = buffer
-            .read_with(cx, |buffer, cx| {
-                buffer.preview_edits(edits.clone().into(), cx)
-            })
+            .read_with(cx, |buffer, cx| buffer.preview_edits(edits.clone(), cx))
             .await;
         let highlighted_edits = cx.read(|cx| {
             edit_preview.highlight_edits(&buffer.read(cx).snapshot(), &edits, include_deletions, cx)