.

go/zodb/storage/fs1/filestorage.go

@@ -595,31 +595,42 @@ func (dh *DataHeader) loadPrevRev(r io.ReaderAt) error {
 	return nil
 }
 
-// TODO LoadBackRef
+// LoadBackRef reads data for the data record and decodes it as backpointer reference.
+// prerequisite: dh loaded and .LenData == 0 (data record with back-pointer)
+// XXX return backPos=-1 if err?
+func (dh *DataHeader) LoadBackRef(r io.ReaderAt) (backPos int64, err error) {
+	if dh.DataLen != 0 {
+		bug(dh, "LoadBack() on non-backpointer data header")
+	}
+
+	_, err = r.ReadAt(dh.workMem[:8], dh.Pos + DataHeaderSize)
+	if err != nil {
+		return 0, dh.err("read data", noEOF(err))
+	}
+
+	backPos = int64(binary.BigEndian.Uint64(dh.workMem[0:]))
+	if !(backPos == 0 || backPos >= dataValidFrom) {
+		return 0, decodeErr(dh, "invalid backpointer: %v", backPos)
+	}
+	if backPos + DataHeaderSize > dh.TxnPos - 8 {
+		return 0, decodeErr(dh, "backpointer (%v) overlaps with txn (%v)", backPos, dh.TxnPos)
+	}
+
+	return backPos, nil
+}
 
 // LoadBack reads and decodes data header for revision linked via back-pointer.
 // prerequisite: dh XXX     .DataLen == 0
 // if link is to zero (means deleted record) io.EOF is returned
 func (dh *DataHeader) LoadBack(r io.ReaderAt) error {
-	if dh.DataLen != 0 {
-		bug(dh, "LoadBack() on non-backpointer data header")
-	}
-
-	_, err := r.ReadAt(dh.workMem[:8], dh.Pos + DataHeaderSize)
+	backPos, err := dh.LoadBackRef(r)
 	if err != nil {
-		return dh.err("read data", noEOF(err))
+		return err
 	}
 
-	backPos := int64(binary.BigEndian.Uint64(dh.workMem[0:]))
 	if backPos == 0 {
 		return io.EOF	// oid was deleted
 	}
-	if backPos < dataValidFrom {
-		return decodeErr(dh, "invalid backpointer: %v", backPos)
-	}
-	if backPos + DataHeaderSize > dh.TxnPos - 8 {
-		return decodeErr(dh, "backpointer (%v) overlaps with txn (%v)", backPos, dh.TxnPos)
-	}
 
 	posCur := dh.Pos
 	tid := dh.Tid

go/zodb/storage/fs1/fs1tools/dump.go

@@ -20,6 +20,8 @@
 package fs1tools
 
 import (
+	"io"
+
 	"lab.nexedi.com/kirr/neo/go/zodb/storage/fs1"
 
 	"lab.nexedi.com/kirr/go123/xerr"
@@ -65,7 +67,7 @@ func dump(w io.Writer, path string, d dumper) (err error) {
 	// buffer for formatting
 	buf := &xfmt.Buffer{}
 	flushBuf := func() error {
-		err := w.Write(buf.Bytes())
+		_, err := w.Write(buf.Bytes())
 		buf.Reset()
 		return err
 	}
@@ -79,8 +81,8 @@ func dump(w io.Writer, path string, d dumper) (err error) {
 	// TODO d.dumpFileHeader
 
 
-	it := fs.IterateRaw(fwd)
-	for i := 0; ; i++ {
+	it := fs.IterateRaw(fs1.IterForward)
+	for {
 		err = it.NextTxn(fs1.LoadAll)
 		if err != nil {
 			if err == io.EOF {
@@ -91,7 +93,7 @@ func dump(w io.Writer, path string, d dumper) (err error) {
 
 		d.dumpTxn(buf, it.Txnh)	// XXX err
 
-		for j := 0; ; j++ {
+		for {
 			err = it.NextData()
 			if err != nil {
 				if err == io.EOF {
@@ -116,14 +118,16 @@ func dump(w io.Writer, path string, d dumper) (err error) {
 
 // dumper is internal interface to implement various dumping modes
 type dumper interface {
-	dumpFileHeader(buf *xfmt.Buffer, *fs1.FileHeader) error
-	dumpTxn(buf *xfmt.Buffer, *fs1.TxnHeader) error
-	dumpData(buf *xfmt.Buffer, *fs1.DataHeader) error
-	dumpTxnPost(buf *xfmt.Buffer, *fs1.TxnHeader) error
+	dumpFileHeader(*xfmt.Buffer, *fs1.FileHeader) error
+	dumpTxn(*xfmt.Buffer, *fs1.TxnHeader) error
+	dumpData(*xfmt.Buffer, *fs1.DataHeader) error
+	dumpTxnPost(*xfmt.Buffer, *fs1.TxnHeader) error
 }
 
 // "normal" dumper
 type dumper1 struct {
+	ntxn  int // current transaction record #
+	ndata int // current data record # inside current transaction
 }
 
 func (d *dumper1) dumpFileHeader(buf *xfmt.Buffer, fh *fs1.FileHeader) error {
@@ -131,20 +135,24 @@ func (d *dumper1) dumpFileHeader(buf *xfmt.Buffer, fh *fs1.FileHeader) error {
 }
 
 func (d *dumper1) dumpTxn(buf *xfmt.Buffer, txnh *fs1.TxnHeader) error {
-	buf .S("Trans #") .D_f("05", i) .S(" tid=") .V(it.Txnh.Tid)
-	buf .S(" time=") .V(it.Txnh.Tid.Time()) .S(" offset=") .D64(it.Txnh.Pos)
-	buf .S("\n    status=") .Qpy(it.Txnh.Status)
-	buf .S(" user=") .Qpyb(it.Txnh.User)
-	buf .S(" description=") .Qpyb(it.Txnh.Description) .S("\n")
+	buf .S("Trans #") .D_f("05", d.ntxn) .S(" tid=") .V(txnh.Tid)
+	buf .S(" time=") .V(txnh.Tid.Time()) .S(" offset=") .D64(txnh.Pos)
+	buf .S("\n    status=") .Qpy(txnh.Status)
+	buf .S(" user=") .Qpyb(txnh.User)
+	buf .S(" description=") .Qpyb(txnh.Description) .S("\n")
+
+	d.ntxn++
+	d.ndata = 0
+	return nil
 }
 
 func (d *dumper1) dumpData(buf *xfmt.Buffer, dh *fs1.DataHeader) error {
-	buf .S("  data #") .D_f("05", j) .S(" oid=") .V(it.Datah.Oid)
+	buf .S("  data #") .D_f("05", d.ndata) .S(" oid=") .V(dh.Oid)
 
-	if it.Datah.DataLen == 0 {
+	if dh.DataLen == 0 {
 		buf .S(" class=undo or abort of object creation")
 
-		backPos, err := it.Datah.LoadBackRef()
+		backPos, err := dh.LoadBackRef()
 		if err != nil {
 			// XXX
 		}
@@ -154,14 +162,18 @@ func (d *dumper1) dumpData(buf *xfmt.Buffer, dh *fs1.DataHeader) error {
 		}
 	} else {
 		// XXX Datah.LoadData()
-		modname, classname = zodb.GetPickleMetadata(...)	// XXX
-		fullclass = "%s.%s" % (modname, classname)
+		//modname, classname = zodb.GetPickleMetadata(...)	// XXX
+		//fullclass = "%s.%s" % (modname, classname)
+		fullclass = "AAA.BBB"	// FIXME stub
 
-		buf .S(" size=") .D(len(...))
+		buf .S(" size=") .D(dh.DataLen)
 		buf .S(" class=") .S(fullclass)
 	}
 
 	buf .S("\n")
+
+	d.ndata++
+	return nil
 }
 
 func (d *dumper1) dumpTxnPost(buf *xfmt.Buffer, txnh *fs1.TxnHeader) error {
@@ -181,14 +193,14 @@ func (d *dumperVerbose) dumpFileHeader(buf *xfmt.Buffer, fh *fs1.FileHeader) err
 
 func (d *dumperVerbose) dumpTxn(buf *xfmt.Buffer, txnh *fs1.TxnHeader) error {
 	buf .S("=" * 60)
-	buf .S("\noffset: ") .D64(it.Txnh.Pos)
-	buf .S("\nend pos: ") .D64(it.Txnh.Pos + it.Txnh.Len)
-	buf .S("\ntransaction id: ") .V(it.Txnh.Tid)
-	buf .S("\ntrec len: ") .D64(it.Txnh.Len)
-	buf .S("\nstatus: ") .Qpy(it.Txnh.Status)
-	buf .S("\nuser: ") .Qpyb(it.Txnh.User)
-	buf .S("\ndescription: ") .Qpyb(it.Txnh.Description)
-	buf .S("\nlen(extra): ") .D(len(it.Txnh.Extension))
+	buf .S("\noffset: ") .D64(txnh.Pos)
+	buf .S("\nend pos: ") .D64(txnh.Pos + txnh.Len)
+	buf .S("\ntransaction id: ") .V(txnh.Tid)
+	buf .S("\ntrec len: ") .D64(txnh.Len)
+	buf .S("\nstatus: ") .Qpy(txnh.Status)
+	buf .S("\nuser: ") .Qpyb(txnh.User)
+	buf .S("\ndescription: ") .Qpyb(txnh.Description)
+	buf .S("\nlen(extra): ") .D(len(txnh.Extension))
 	buf .S("\n")
 	return nil
 }
@@ -219,6 +231,6 @@ func (d *dumperVerbose) dumpTxnPost(buf *xfmt.Buffer, txnh *fs1.TxnHeader) error
 	// NOTE printing the same .Len twice
 	// we do not print/check redundant len here because our
 	// FileStorage code checks/reports this itself
-	buf .S("redundant trec len: " .D64(it.Txnh.Len)) .S("\n")
+	buf .S("redundant trec len: " .D64(txnh.Len)) .S("\n")
 	return nil
 }