use Automerge as Document instead of AutoCommit

This allows a lot of operations to drop mut.

1 files changed, 12 insertions, 5 deletions

diff --git a/src/remake/switch.rs b/src/remake/switch.rs
index 9aae748..e60c942 100644
--- a/src/remake/switch.rs
+++ b/src/remake/switch.rs
@@ -219,10 +219,10 @@ async fn switch<H: Host>(
     // 2. Build (or reuse), verify and replay without holding any lock.
     let (new_doc, copy_heads, mut stats) = tokio::task::spawn_blocking(
         move || -> Result<(Document, Vec<ChangeHash>, ReplayStats), String> {
-            let mut copy = copy;
+            let copy = copy;
             let snapshot = match prebuilt {
                 Some(snapshot) => snapshot,
-                None => snapshot::build(&mut copy, &request.params())
+                None => snapshot::build(&copy, &request.params())
                     .map_err(|error| format!("snapshot build failed: {error}"))?,
             };
             if snapshot.epoch != expected {
@@ -235,13 +235,20 @@ async fn switch<H: Host>(
             // A fresh actor: this node's writes in the new epoch.
             let mut doc = snapshot.doc.with_actor(actor);
 
+            // The carried record and the replayed writes go into one change.
+            let heads = copy.get_heads();
+            let paths = delta::changed_paths(&copy, &base, &heads);
+            let mut transaction = doc.transaction();
+
             // Keep this remake's record visible in the new epoch, for its history.
-            if carry_record && let Err(error) = store::copy_path(&copy, &mut doc, &record_path) {
+            if carry_record
+                && let Err(error) = store::copy_path(&copy, &mut transaction, &record_path)
+            {
                 warn!(error = %error, "Could not carry the remake record into the new epoch");
             }
 
-            let heads = copy.get_heads();
-            let stats = delta::replay(&mut copy, &base, &heads, &mut doc, &translator);
+            let stats = delta::replay_paths(&copy, &mut transaction, &paths, &translator);
+            transaction.commit();
             Ok((doc, heads, stats))
         },
     )