.

wcfs/internal/zdata/δftail.go

@@ -339,43 +339,11 @@ func (δftail *_ΔFileTail) _rebuild1(foid zodb.Oid, δZtail *zodb.ΔTail, db *z
 		panic("rebuild1: vδE != nil")
 	}
 
-	vδE := []_ΔFileEpoch{}
-	vδZ := δZtail.Data()
-	atPrev := δZtail.Tail()
-	for i := 0; i < len(vδZ); i++ {
-		δZ := vδZ[i]
-
-		fchanged := false
-		for _, oid := range δZ.Changev {
-			if oid == foid {
-				fchanged = true
-				break
-			}
-		}
-		if !fchanged {
-			continue
-		}
-
-		δ, err := zfilediff(db, foid, atPrev, δZ.Rev)
+	vδE, err := vδEBuild(foid, δZtail, db)
 	if err != nil {
 		return err
 	}
 
-		if δ != nil {
-			δE := _ΔFileEpoch{
-				Rev:             δZ.Rev,
-				oldRoot:         δ.blktabOld,
-				newRoot:         δ.blktabNew,
-				oldBlkSize:      δ.blksizeOld,
-				newBlkSize:      δ.blksizeNew,
-				oldTrackSetZBlk: nil, // nothing was tracked
-			}
-			vδE = append(vδE, δE)
-		}
-
-		atPrev = δZ.Rev
-	}
-
 	δftail.vδE = vδE
 	return nil
 }
@@ -971,7 +939,53 @@ func (δFtail *ΔFtail) _BlkRevAt(ctx context.Context, zfile *ZBigFile, blk int6
 }
 
 
-// ----------------------------------------
+// ---- vδEBuild (rebuild core) ----
+
+// vδEBuild builds vδE from vδZ for file.
+//
+// XXX place ok?
+func vδEBuild(foid zodb.Oid, δZtail *zodb.ΔTail, db *zodb.DB) (vδE []_ΔFileEpoch, err error) {
+	defer xerr.Contextf(&err, "file<%s>: build vδE", foid)
+
+	vδE  = []_ΔFileEpoch{}
+	vδZ := δZtail.Data()
+	atPrev := δZtail.Tail()
+	for i := 0; i < len(vδZ); i++ {
+		δZ := vδZ[i]
+
+		fchanged := false
+		for _, oid := range δZ.Changev {
+			if oid == foid {
+				fchanged = true
+				break
+			}
+		}
+		if !fchanged {
+			continue
+		}
+
+		δ, err := zfilediff(db, foid, atPrev, δZ.Rev)
+		if err != nil {
+			return nil, err
+		}
+
+		if δ != nil {
+			δE := _ΔFileEpoch{
+				Rev:             δZ.Rev,
+				oldRoot:         δ.blktabOld,
+				newRoot:         δ.blktabNew,
+				oldBlkSize:      δ.blksizeOld,
+				newBlkSize:      δ.blksizeNew,
+				oldTrackSetZBlk: nil, // nothing was tracked
+			}
+			vδE = append(vδE, δE)
+		}
+
+		atPrev = δZ.Rev
+	}
+
+	return vδE, nil
+}
 
 
 // zfilediff returns direct difference for ZBigFile<foid> old..new .