.

wcfs/internal/xbtree/δbtail.go

@@ -308,16 +308,28 @@ func (δBtail *ΔBtail) rebuildAll() (err error) {
 	tracefΔBtail("\nRebuildAll @%s..@%s    trackNewRoots: %s\n", δBtail.Tail(), δBtail.Head(), δBtail.trackNewRoots)
 
 	for root := range δBtail.trackNewRoots {
+		delete(δBtail.trackNewRoots, root)
 		δBtail.rebuild1(root)
 	}
 
 	return nil
 }
 
+// rebuild1IfNeeded rebuilds ΔBtail for single root if that root needs rebuilding.
+func (δBtail *ΔBtail) rebuild1IfNeeded(root zodb.Oid) error {
+	// XXX locking
+	_, ok := δBtail.trackNewRoots[root]
+	if !ok {
+		return nil
+	}
+
+	delete(δBtail.trackNewRoots, root)
+	return δBtail.rebuild1(root)
+}
+
 // rebuild1 rebuilds ΔBtail for single root.
 func (δBtail *ΔBtail) rebuild1(root zodb.Oid) error {
 	// XXX locking
-	delete(δBtail.trackNewRoots, root)
 	δTtail := δBtail.vδTbyRoot[root] // must be there
 	δtrackSet, δrevSet, err := δTtail.rebuild(root, δBtail.δZtail, δBtail.db)
 	if err != nil {
@@ -328,6 +340,7 @@ func (δBtail *ΔBtail) rebuild1(root zodb.Oid) error {
 	return nil
 }
 
+
 // rebuild rebuilds ΔTtail taking trackNew requests into account.
 //
 // It returns:
@@ -338,7 +351,7 @@ func (δBtail *ΔBtail) rebuild1(root zodb.Oid) error {
 //
 // XXX place
 func (δTtail *ΔTtail) rebuild(root zodb.Oid, δZtail *zodb.ΔTail, db *zodb.DB) (δtrackSet blib.PPTreeSubSet, δrevSet setTid, err error) {
-	defer xerr.Context(&err, "ΔTtail rebuild")
+	defer xerr.Contextf(&err, "ΔTtail<%s> rebuild", root)
 	// XXX locking
 
 	tracefΔBtail("\nRebuild %s @%s .. @%s\n", root, δZtail.Tail(), δZtail.Head())
@@ -765,13 +778,18 @@ func (δBtail *ΔBtail) GetAt(ctx context.Context, root *Tree, key Key, at zodb.
 	// XXX key not tracked		-> panic
 	// XXX at not ∈ (tail, head]	-> panic
 
-	// XXX dirty -> rebuild
+	// XXX locking
 
 	rootAt := root.PJar().At()
 	if rootAt != δBtail.Head() {
 		panicf("δBtail: root.at (@%s)  !=  head (@%s)", rootAt, δBtail.Head())
 	}
 
+	err = δBtail.rebuild1IfNeeded(root.POid())
+	if err != nil {
+		return
+	}
+
 	δTtail := δBtail.vδTbyRoot[root.POid()]
 	if δTtail == nil {
 		panicf("δBtail: root<%s> not tracked", root.POid())
@@ -842,7 +860,12 @@ func (δBtail *ΔBtail) GetAt(ctx context.Context, root *Tree, key Key, at zodb.
 func (δBtail *ΔBtail) SliceByRootRev(root zodb.Oid, lo, hi zodb.Tid) /*readonly*/[]ΔTree {
 	xtail.AssertSlice(δBtail, lo, hi)
 	// XXX locking
-	// XXX rebuild
+
+	err := δBtail.rebuild1IfNeeded(root)
+	if err != nil {
+		panic(err) // XXX
+	}
+
 	δTtail, ok := δBtail.vδTbyRoot[root]
 	if !ok {
 		return []ΔTree{}