.

wcfs/internal/zdata/δftail.go

@@ -374,6 +374,28 @@ func (δFtail *ΔFtail) Update(δZ *zodb.EventCommit) (_ ΔF, err error) {
 // ForgetPast discards all δFtail entries with rev ≤ revCut.
 func (δFtail *ΔFtail) ForgetPast(revCut zodb.Tid) {
 	δFtail.δBtail.ForgetPast(revCut)
+
+	// XXX locking
+	// XXX keep index which file changed epoch where (similarly to ΔBtail),
+	// and, instead of scanning all files, trim vδE only on files that is really necessary.
+	for _, δftail := range δFtail.byFile {
+		δftail.forgetPast(revCut)
+	}
+}
+
+func (δftail *_ΔFileTail) forgetPast(revCut zodb.Tid) {
+	// XXX locking
+	icut := 0
+	for ; icut < len(δftail.vδE); icut++ {
+		if δftail.vδE[icut].Rev > revCut {
+			break
+		}
+	}
+
+	// vδE[:icut] should be forgotten
+	if icut > 0 { // XXX workarond for ΔFtail.ForgetPast calling forgetPast on all files
+		δftail.vδE = append([]_ΔFileEpoch(nil), δftail.vδE[icut:]...)
+	}
 }
 
 // XXX don't need

wcfs/internal/zdata/δftail_test.go

@@ -177,6 +177,9 @@ func testΔFtail(t_ *testing.T, testq chan ΔFTestEntry) {
 	t := xbtreetest.NewT(t_)
 	X := exc.Raiseif
 
+	// XXX start δFtail when zfile is not yet exists
+	//     this way we'll verify how ΔFtail rebuilds vδE for started-to-be-tracked file
+
 	δFtail := NewΔFtail(t.Head().At, t.DB)
 
 	// load zfile via root['treegen/file']
@@ -187,7 +190,7 @@ func testΔFtail(t_ *testing.T, testq chan ΔFTestEntry) {
 	err = zroot.PActivate(ctx);  X(err)
 	zfile := zroot.Data["treegen/file"].(*ZBigFile)
 	zroot.PDeactivate()
-	zfileOid := zfile.POid()
+	foid := zfile.POid()
 	err = zfile.PActivate(ctx);  X(err)
 	blktabOid := zfile.blktab.POid()
 	if blktabOid != t.Root() {
@@ -400,7 +403,7 @@ func testΔFtail(t_ *testing.T, testq chan ΔFTestEntry) {
 		}
 		δfilesOK := setOid{}
 		if δfok != nil {
-			δfilesOK.Add(zfileOid)
+			δfilesOK.Add(foid)
 		}
 		if !δfiles.Equal(δfilesOK) {
 			t.Errorf("wrong δF.ByFile:\nhave keys: %s\nwant keys: %s", δfiles, δfilesOK)
@@ -408,7 +411,7 @@ func testΔFtail(t_ *testing.T, testq chan ΔFTestEntry) {
 		}
 
 		// verify δf
-		δf := δF.ByFile[zfileOid]
+		δf := δF.ByFile[foid]
 		if !reflect.DeepEqual(δf, δfok) {
 			t.Errorf("δf:\nhave: %v\nwant: %v", δf, δfok)
 		}
@@ -451,6 +454,19 @@ func testΔFtail(t_ *testing.T, testq chan ΔFTestEntry) {
 			//t.Logf("#   vδt: %s", vδfstr(δFtail.SliceByFileRev(zfile, δFtail.Tail(), δFtail.Head())))
 		}
 
+		// verify vδE
+		vδEok := []_ΔFileEpoch{}
+		for _, δf := range vδf {
+			if δf.Epoch {
+				vδEok = append(vδEok, _ΔFileEpoch{Rev: δf.Rev}) // XXX + root,size
+			}
+		}
+		δftail := δFtail.byFile[foid]
+		if !reflect.DeepEqual(δftail.vδE, vδEok) {
+			t.Errorf("vδE:\nhave: %v\nwant: %v", δftail.vδE, vδEok)
+		}
+
+
 		// SliceByFileRev
 		for j := 0; j < len(vδf); j++ {
 			for k := j; k < len(vδf); k++ {