feat: add direct rewind materialization fast path

Cargo.toml

@@ -5,6 +5,7 @@ members = [
   "packages/treecrdt-postgres-rs",
   "packages/treecrdt-riblt-wasm",
   "packages/treecrdt-sqlite-ext",
+  "packages/treecrdt-test-support",
   "packages/treecrdt-wasm",
 ]
 resolver = "2"

examples/playground/src/App.tsx

@@ -162,7 +162,6 @@ export default function App() {
     persistSyncSettings(syncServerUrl, syncTransportMode);
   }, [syncServerUrl, syncTransportMode]);
 
-  const counterRef = useRef(0);
   const lamportRef = useRef(0);
   const initEpochRef = useRef(0);
   const disposedRef = useRef(false);
@@ -483,18 +482,14 @@ export default function App() {
       const active = nextClient ?? clientRef.current ?? client;
       if (!active) return;
       try {
-        const [lamport, counter] = await Promise.all([
-          active.meta.headLamport(),
-          replica ? active.meta.replicaMaxCounter(replica) : Promise.resolve(0),
-        ]);
+        const lamport = await active.meta.headLamport();
         lamportRef.current = Math.max(lamportRef.current, lamport);
         setHeadLamport(lamportRef.current);
-        counterRef.current = Math.max(counterRef.current, counter);
       } catch (err) {
         console.error("Failed to refresh meta", err);
       }
     },
-    [client, replica]
+    [client]
   );
 
   const refreshParentsScheduledRef = useRef(false);
@@ -831,7 +826,6 @@ export default function App() {
     setPayloadVersion((v) => v + 1);
     knownOpsRef.current = new Set();
     setCollapse({ defaultCollapsed: true, overrides: new Set([ROOT_ID]) });
-    counterRef.current = 0;
     lamportRef.current = 0;
     setHeadLamport(0);
     setTotalNodes(null);
@@ -887,7 +881,6 @@ export default function App() {
       await verifyLocalOps([op]);
 
       lamportRef.current = Math.max(lamportRef.current, op.meta.lamport);
-      counterRef.current = Math.max(counterRef.current, op.meta.id.counter);
       setHeadLamport(lamportRef.current);
 
       notifyLocalUpdate([op]);
@@ -916,7 +909,6 @@ export default function App() {
       scheduleRefreshParents(parentsAffectedByOps(stateBefore, [op]));
       scheduleRefreshNodeCount();
       lamportRef.current = Math.max(lamportRef.current, op.meta.lamport);
-      counterRef.current = Math.max(counterRef.current, op.meta.id.counter);
       setHeadLamport(lamportRef.current);
     } catch (err) {
       console.error("Failed to append move op", err);
@@ -1014,7 +1006,6 @@ export default function App() {
 
       for (const op of ops) {
         lamportRef.current = Math.max(lamportRef.current, op.meta.lamport);
-        counterRef.current = Math.max(counterRef.current, op.meta.id.counter);
       }
       setHeadLamport(lamportRef.current);
 
@@ -1067,7 +1058,6 @@ export default function App() {
         await ensureChildrenLoaded(parentId, { force: true });
       }
       lamportRef.current = Math.max(lamportRef.current, op.meta.lamport);
-      counterRef.current = Math.max(counterRef.current, op.meta.id.counter);
       setHeadLamport(lamportRef.current);
       setCollapse((prev) => {
         const overrides = new Set(prev.overrides);

examples/playground/src/playground/hooks/usePlaygroundSync.ts

@@ -1,4 +1,4 @@
-import { useEffect, useRef, useState } from 'react';
+import { useCallback, useEffect, useRef, useState } from 'react';
 import type { Operation } from '@treecrdt/interface';
 import { bytesToHex } from '@treecrdt/interface/ids';
 import { type TreecrdtIdentityChainV1 } from '@treecrdt/auth';
@@ -285,6 +285,17 @@ export function usePlaygroundSync(opts: UsePlaygroundSyncOptions): PlaygroundSyn
     setPeers(merged);
   };
 
+  const refreshLoadedSyncState = useCallback(
+    async (extraParentIds: Iterable<string> = []) => {
+      await refreshMeta();
+      const parentIds = new Set(Object.keys(treeStateRef.current.childrenByParent));
+      for (const parentId of extraParentIds) parentIds.add(parentId);
+      await refreshParents(Array.from(parentIds));
+      await refreshNodeCount();
+    },
+    [refreshMeta, refreshNodeCount, refreshParents, treeStateRef]
+  );
+
   const isRemotePeerId = (peerId: string) => peerId.startsWith('remote:');
   const syncOnceOptionsForPeer = (peerId: string, localCodewordsPerMessage: number) => ({
     maxCodewords: PLAYGROUND_SYNC_MAX_CODEWORDS,
@@ -629,9 +640,7 @@ export function usePlaygroundSync(opts: UsePlaygroundSyncOptions): PlaygroundSyn
         if (lastErr) throw lastErr;
         throw new Error('No peers responded to sync.');
       }
-      await refreshMeta();
-      await refreshParents(Object.keys(treeStateRef.current.childrenByParent));
-      await refreshNodeCount();
+      await refreshLoadedSyncState();
     } catch (err) {
       console.error('Sync failed', err);
       setSyncError(formatSyncError(err));
@@ -702,9 +711,7 @@ export function usePlaygroundSync(opts: UsePlaygroundSyncOptions): PlaygroundSyn
         if (lastErr) throw lastErr;
         throw new Error('No peers responded to sync.');
       }
-      await refreshMeta();
-      await refreshParents(Object.keys(treeStateRef.current.childrenByParent));
-      await refreshNodeCount();
+      await refreshLoadedSyncState();
     } catch (err) {
       console.error('Scoped sync failed', err);
       setSyncError(formatSyncError(err));
@@ -787,11 +794,7 @@ export function usePlaygroundSync(opts: UsePlaygroundSyncOptions): PlaygroundSyn
           );
         }
 
-        await refreshMeta();
-        const parentIds = new Set(Object.keys(treeStateRef.current.childrenByParent));
-        parentIds.add(viewRootId);
-        await refreshParents(Array.from(parentIds));
-        await refreshNodeCount();
+        await refreshLoadedSyncState([viewRootId]);
 
         autoSyncDoneRef.current = true;
         if (typeof window !== 'undefined') {
@@ -819,9 +822,7 @@ export function usePlaygroundSync(opts: UsePlaygroundSyncOptions): PlaygroundSyn
     authMaterial.localTokensB64.length,
     autoSyncJoinTick,
     joinMode,
-    refreshMeta,
-    refreshNodeCount,
-    refreshParents,
+    refreshLoadedSyncState,
     syncBusy,
     viewRootId,
   ]);
@@ -981,8 +982,7 @@ export function usePlaygroundSync(opts: UsePlaygroundSyncOptions): PlaygroundSyn
         if (debugSync && ops.length > 0) {
           console.debug(`[sync:${selfPeerId}] applyOps(${ops.length})`);
         }
-        const affected =
-          ops.length > 0 ? ((await client.ops.appendMany(ops)) as unknown as string[]) : [];
+        const affected = ops.length > 0 ? await client.ops.appendMany(ops) : [];
         await onRemoteOpsApplied(ops, affected);
       },
     };

packages/treecrdt-core/src/lib.rs

@@ -17,13 +17,18 @@ pub use ids::{Lamport, NodeId, OperationId, ReplicaId};
 pub use materialization::{
     apply_incremental_ops_with_delta, apply_persisted_remote_ops_with_delta,
     catch_up_materialized_state, materialize_persisted_remote_ops_with_delta,
-    IncrementalApplyResult, MaterializationCursor, MaterializationFrontier, MaterializationHead,
-    MaterializationKey, MaterializationState, PersistedRemoteApplyResult, PersistedRemoteStores,
+    orchestrate_persisted_remote_append, try_direct_rewind_catch_up_materialized_state,
+    try_shortcut_out_of_order_payload_noops, CatchUpResult, FrontierRewindStorage,
+    IncrementalApplyResult, MaterializationCursor, MaterializationFrontier,
+    MaterializationFrontierRef, MaterializationHead, MaterializationKey, MaterializationState,
+    MaterializationStateRef, PayloadNoopShortcut, PersistedRemoteApplyResult,
+    PersistedRemoteStores,
 };
 pub use ops::{cmp_op_key, cmp_ops, Operation, OperationKind, OperationMetadata};
 pub use traits::{
-    Clock, IndexProvider, LamportClock, MemoryNodeStore, MemoryPayloadStore, MemoryStorage,
-    NodeStore, NoopParentOpIndex, NoopStorage, ParentOpIndex, PayloadStore, Storage,
+    Clock, ExactNodeStore, ExactPayloadStore, IndexProvider, LamportClock, MemoryNodeStore,
+    MemoryPayloadStore, MemoryStorage, NodeStore, NoopParentOpIndex, NoopStorage, ParentOpIndex,
+    PayloadStore, Storage, TruncatingParentOpIndex,
 };
 pub use tree::{
     ApplyDelta, LocalFinalizePlan, LocalPlacement, NodeExport, NodeSnapshotExport, TreeCrdt,