.

wcfs/δftail.go

@@ -176,9 +176,33 @@ func (δFtail *ΔFtail) SliceByFileRev(file *BigFile, lo, hi zodb.Tid) /*readonl
 
 	// XXX activate zfile?
 	vδT := δFtail.δBtail.SliceByRootRev(file.zfile.blktab, lo, hi)
-	//kv = kvAtTail
+	vδZ := δFtail.δBtail.δZtail.SliceByRev(lo, hi)
+
+	// state of `{} blk -> zblk` at current change
+	δblktab := map[int64]zodb.Oid{}
+	zblkBoundTo := map[zodb.Oid]SetI64 // {} zblk -> {}blk
+
+	iz := len(vδZ) - 1
+	it := len(vδT) - 1
+	for (iz >= 0 && it >= 0) {	// XXX -> ||
+		δZ := vδZ[iz]
+		δT := vδT[it]
+		if δZ.Rev >= δT.Rev {
+			for _, oid := range δZ.Changev {
+				// XXX oid -> tracked ZBlk?
+				// ZBlk -> bound to {}blk @head
+				for blk := range boundToAtHead {
+					if !δblktab.Has(blk) {
+						δblktab[blk] = oid
+					}
+				}
+			}
+		}
+		if δT.Rev >= δZ.Rev {
+			...
+		}
+	}
 
-	_ = vδT
 	panic("TODO")
 
 }