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Commit 1c4409fb authored by Kirill Smelkov's avatar Kirill Smelkov
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parent 4c4ce2ea
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Showing with 68 additions and 73 deletions
go/zodb/storage/fs1/format.go
View file @ 1c4409fb
......@@ -137,10 +137,9 @@ func errf(e ierr, subj, format string, a ...interface{}) error {
return e.err(subj, fmt.Errorf(format, a...))
}
// decodeErr is syntactic shortcut for errf("decode", ...)
// TODO in many places "decode" -> "selfcheck"
func decodeErr(e ierr, format string, a ...interface{}) error {
return errf(e, "decode", format, a...)
// checkErr is syntactic shortcut for errf("check", ...)
func checkErr(e ierr, format string, a ...interface{}) error {
return errf(e, "check", format, a...)
}
// bug panics with errf("bug", ...)
......@@ -167,7 +166,8 @@ func (fh *FileHeader) Load(r io.ReaderAt) error {
// --- Transaction record ---
// HeaderLen returns whole transaction header length including variable part.
// HeaderLen returns whole transaction header length including its variable part.
//
// NOTE: data records start right after transaction header.
func (txnh *TxnHeader) HeaderLen() int64 {
return TxnHeaderFixSize + int64(len(txnh.workMem))
......@@ -209,20 +209,25 @@ const (
LoadNoStrings = 0x01 // do not load user/desc/ext strings
)
// Load reads and decodes transaction record header.
// Load reads and decodes transaction record header @ pos.
//
// Both transaction header starting at pos, and redundant length of previous
// transaction are loaded. The data read is verified for consistency lightly.
//
// No prerequisite requirements are made to previous txnh state.
//
// pos: points to transaction start
// no prerequisite requirements are made to previous txnh state
// TODO describe what happens at EOF and when .LenPrev is still valid
// Rules for .Len/.LenPrev returns:
//
// rules for Len/LenPrev returns:
// Len == 0 transaction header could not be read
// Len == -1 EOF forward
// Len >= TxnHeaderFixSize transaction was read normally
// .Len == 0 transaction header could not be read
// .Len == -1 EOF forward
// .Len >= TxnHeaderFixSize transaction was read normally
//
// LenPrev == 0 prev record length could not be read
// LenPrev == -1 EOF backward
// LenPrev >= TxnHeaderFixSize LenPrev was read/checked normally
// .LenPrev == 0 prev record length could not be read
// .LenPrev == -1 EOF backward
// .LenPrev >= TxnHeaderFixSize LenPrev was read/checked normally
//
// For example when pos points to the end of file .Len will be returned = -1, but
// .LenPrev will be usually valid if file has at least 1 transaction.
func (txnh *TxnHeader) Load(r io.ReaderAt, pos int64, flags TxnLoadFlags) error {
if cap(txnh.workMem) < txnXHeaderFixSize {
txnh.workMem = make([]byte, txnXHeaderFixSize, 256 /* to later avoid allocation for typical strings */)
......@@ -248,14 +253,14 @@ func (txnh *TxnHeader) Load(r io.ReaderAt, pos int64, flags TxnLoadFlags) error
if n >= 0 {
lenPrev := 8 + int64(binary.BigEndian.Uint64(work[8-8:]))
if lenPrev < TxnHeaderFixSize {
return decodeErr(txnh, "invalid prev record length: %v", lenPrev)
return checkErr(txnh, "invalid prev record length: %v", lenPrev)
}
posPrev := txnh.Pos - lenPrev
if posPrev < txnValidFrom {
return decodeErr(txnh, "prev record length goes beyond valid area: %v", lenPrev)
return checkErr(txnh, "prev record length goes beyond valid area: %v", lenPrev)
}
if posPrev < txnValidFrom + TxnHeaderFixSize && posPrev != txnValidFrom {
return decodeErr(txnh, "prev record does not land exactly at valid area start: %v", posPrev)
return checkErr(txnh, "prev record does not land exactly at valid area start: %v", posPrev)
}
txnh.LenPrev = lenPrev
}
......@@ -279,19 +284,19 @@ func (txnh *TxnHeader) Load(r io.ReaderAt, pos int64, flags TxnLoadFlags) error
txnh.Tid = zodb.Tid(binary.BigEndian.Uint64(work[8+0:]))
if !txnh.Tid.Valid() {
return decodeErr(txnh, "invalid tid: %v", txnh.Tid)
return checkErr(txnh, "invalid tid: %v", txnh.Tid)
}
tlen := 8 + int64(binary.BigEndian.Uint64(work[8+8:]))
if tlen < TxnHeaderFixSize {
return decodeErr(txnh, "invalid txn record length: %v", tlen)
return checkErr(txnh, "invalid txn record length: %v", tlen)
}
// XXX also check tlen to not go beyond file size ?
txnh.Len = tlen
txnh.Status = zodb.TxnStatus(work[8+16])
if !txnh.Status.Valid() {
return decodeErr(txnh, "invalid status: %v", txnh.Status)
return checkErr(txnh, "invalid status: %v", txnh.Status)
}
......@@ -301,7 +306,7 @@ func (txnh *TxnHeader) Load(r io.ReaderAt, pos int64, flags TxnLoadFlags) error
lstr := int(luser) + int(ldesc) + int(lext)
if TxnHeaderFixSize + int64(lstr) + 8 > txnh.Len {
return decodeErr(txnh, "strings overlap with txn boundary: %v / %v", lstr, txnh.Len)
return checkErr(txnh, "strings overlap with txn boundary: %v / %v", lstr, txnh.Len)
}
// NOTE we encode whole strings length into len(.workMem)
......@@ -387,12 +392,12 @@ func (txnh *TxnHeader) LoadPrev(r io.ReaderAt, flags TxnLoadFlags) error {
}
if txnh.Len != lenPrev {
return decodeErr(txnh, "head/tail lengths mismatch: %v, %v", txnh.Len, lenPrev)
return checkErr(txnh, "head/tail lengths mismatch: %v, %v", txnh.Len, lenPrev)
}
// check tid↓ if we had txnh for "cur" loaded
if lenCur > 0 && txnh.Tid >= tidCur {
return decodeErr(txnh, "tid monitonity broken: %v ; next: %v", txnh.Tid, tidCur)
return checkErr(txnh, "tid monitonity broken: %v ; next: %v", txnh.Tid, tidCur)
}
return nil
......@@ -426,7 +431,7 @@ func (txnh *TxnHeader) LoadNext(r io.ReaderAt, flags TxnLoadFlags) error {
// NOTE also: err could be EOF
if txnh.LenPrev != 0 && txnh.LenPrev != lenCur {
t := &TxnHeader{Pos: posCur} // txn for which we discovered problem
return decodeErr(t, "head/tail lengths mismatch: %v, %v", lenCur, txnh.LenPrev)
return checkErr(t, "head/tail lengths mismatch: %v, %v", lenCur, txnh.LenPrev)
}
if err != nil {
......@@ -435,7 +440,7 @@ func (txnh *TxnHeader) LoadNext(r io.ReaderAt, flags TxnLoadFlags) error {
// check tid↑
if txnh.Tid <= tidCur {
return decodeErr(txnh, "tid monotonity broken: %v ; prev: %v", txnh.Tid, tidCur)
return checkErr(txnh, "tid monotonity broken: %v ; prev: %v", txnh.Tid, tidCur)
}
return nil
......@@ -456,6 +461,7 @@ func (dh *DataHeader) Len() int64 {
// Load reads and decodes data record header.
//
// pos: points to data header start
// no prerequisite requirements are made to previous dh state
func (dh *DataHeader) Load(r io.ReaderAt, pos int64) error {
......@@ -475,36 +481,36 @@ func (dh *DataHeader) Load(r io.ReaderAt, pos int64) error {
dh.Oid = zodb.Oid(binary.BigEndian.Uint64(dh.workMem[0:])) // XXX -> zodb.Oid.Decode() ?
dh.Tid = zodb.Tid(binary.BigEndian.Uint64(dh.workMem[8:])) // XXX -> zodb.Tid.Decode() ?
if !dh.Tid.Valid() {
return decodeErr(dh, "invalid tid: %v", dh.Tid)
return checkErr(dh, "invalid tid: %v", dh.Tid)
}
dh.PrevRevPos = int64(binary.BigEndian.Uint64(dh.workMem[16:]))
dh.TxnPos = int64(binary.BigEndian.Uint64(dh.workMem[24:]))
if dh.TxnPos < txnValidFrom {
return decodeErr(dh, "invalid txn position: %v", dh.TxnPos)
return checkErr(dh, "invalid txn position: %v", dh.TxnPos)
}
if dh.TxnPos + TxnHeaderFixSize > pos {
return decodeErr(dh, "txn position not decreasing: %v", dh.TxnPos)
return checkErr(dh, "txn position not decreasing: %v", dh.TxnPos)
}
if dh.PrevRevPos != 0 { // zero means there is no previous revision
if dh.PrevRevPos < dataValidFrom {
return decodeErr(dh, "invalid prev revision position: %v", dh.PrevRevPos)
return checkErr(dh, "invalid prev revision position: %v", dh.PrevRevPos)
}
if dh.PrevRevPos + DataHeaderSize > dh.TxnPos - 8 {
return decodeErr(dh, "prev revision position (%v) overlaps with txn (%v)", dh.PrevRevPos, dh.TxnPos)
return checkErr(dh, "prev revision position (%v) overlaps with txn (%v)", dh.PrevRevPos, dh.TxnPos)
}
}
verlen := binary.BigEndian.Uint16(dh.workMem[32:])
if verlen != 0 {
return decodeErr(dh, "non-zero version: #%v", verlen)
return checkErr(dh, "non-zero version: #%v", verlen)
}
dh.DataLen = int64(binary.BigEndian.Uint64(dh.workMem[34:]))
if dh.DataLen < 0 {
// XXX also check DataLen < max ?
return decodeErr(dh, "invalid data len: %v", dh.DataLen)
return checkErr(dh, "invalid data len: %v", dh.DataLen)
}
return nil
......@@ -512,8 +518,8 @@ func (dh *DataHeader) Load(r io.ReaderAt, pos int64) error {
// LoadPrevRev reads and decodes previous revision data record header.
//
// prerequisite: dh .Oid .Tid .PrevRevPos are initialized:
// - TODO describe how
// prerequisite: dh .Oid .Tid .PrevRevPos are initialized.
//
// when there is no previous revision: io.EOF is returned
func (dh *DataHeader) LoadPrevRev(r io.ReaderAt) error {
if dh.PrevRevPos == 0 {
......@@ -522,31 +528,30 @@ func (dh *DataHeader) LoadPrevRev(r io.ReaderAt) error {
posCur := dh.Pos
err := dh.loadPrevRev(r)
err := dh.loadPrevRev(r, dh.PrevRevPos)
if err != nil {
// data record @...: loading prev rev: data record @...: ...
err = &DataError{posCur, "loading prev rev", err}
// data record @...: -> (prev rev): data record @...: ...
err = &DataError{posCur, "-> (prev rev)", err}
}
return err
}
func (dh *DataHeader) loadPrevRev(r io.ReaderAt) error {
// worker for LoadPrevRev and LoadBack
func (dh *DataHeader) loadPrevRev(r io.ReaderAt, prevPos int64) error {
oid := dh.Oid
tid := dh.Tid
err := dh.Load(r, dh.PrevRevPos)
err := dh.Load(r, prevPos)
if err != nil {
return err
}
if dh.Oid != oid {
// XXX vvv valid only if DataError prints oid
return decodeErr(dh, "oid mismatch")
return checkErr(dh, "oid mismatch: %s -> %s", oid, dh.Oid)
}
if dh.Tid >= tid {
// XXX vvv valid only if DataError prints tid
return decodeErr(dh, "tid mismatch")
return checkErr(dh, "tid not ↓: %s -> %s", tid, dh.Tid)
}
return nil
......@@ -567,10 +572,10 @@ func (dh *DataHeader) LoadBackRef(r io.ReaderAt) (backPos int64, err error) {
backPos = int64(binary.BigEndian.Uint64(dh.workMem[0:]))
if !(backPos == 0 || backPos >= dataValidFrom) {
return 0, decodeErr(dh, "invalid backpointer: %v", backPos)
return 0, checkErr(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 0, checkErr(dh, "backpointer (%v) overlaps with txn (%v)", backPos, dh.TxnPos)
}
return backPos, nil
......@@ -578,7 +583,8 @@ func (dh *DataHeader) LoadBackRef(r io.ReaderAt) (backPos int64, err error) {
// LoadBack reads and decodes data header for revision linked via back-pointer.
//
// prerequisite: dh XXX .DataLen == 0
// prerequisite: dh is loaded and .DataLen == 0
//
// if link is to zero (means deleted record) io.EOF is returned
func (dh *DataHeader) LoadBack(r io.ReaderAt) error {
backPos, err := dh.LoadBackRef(r)
......@@ -591,26 +597,11 @@ func (dh *DataHeader) LoadBack(r io.ReaderAt) error {
}
posCur := dh.Pos
tid := dh.Tid
// TODO compare this with loadPrevRev() way
err = func() error {
err := dh.Load(r, backPos)
err = dh.loadPrevRev(r, backPos)
if err != nil {
return err
}
// XXX also dh.Oid == oid ?
// but in general back pointer might point to record with different oid
if dh.Tid >= tid {
return decodeErr(dh, "tid not decreasing")
}
return err
}()
if err != nil {
err = &DataError{posCur, "loading back rev", err}
// data record @...: -> (prev rev): data record @...: ...
err = &DataError{posCur, "-> (back)", err}
}
return err
......@@ -618,12 +609,13 @@ func (dh *DataHeader) LoadBack(r io.ReaderAt) error {
// LoadNext reads and decodes data header for next data record in the same transaction.
//
// prerequisite: dh .Pos .DataLen are initialized
// when there is no more data records: io.EOF is returned
// prerequisite: dh .Pos .DataLen are initialized.
//
// When there is no more data records: io.EOF is returned.
func (dh *DataHeader) LoadNext(r io.ReaderAt, txnh *TxnHeader) error {
err := dh.loadNext(r, txnh)
if err != nil && err != io.EOF {
err = txnh.err("iterating", err)
err = txnh.err("-> (iter data)", err)
}
return err
}
......@@ -640,7 +632,9 @@ func (dh *DataHeader) loadNext(r io.ReaderAt, txnh *TxnHeader) error {
}
if nextPos + DataHeaderSize > txnTailPos {
return &DataError{nextPos, "decode", fmt.Errorf("data record header overlaps txn boundary")} // XXX
return &DataError{nextPos, "check",
fmt.Errorf("data record header [..., %d] overlaps txn boundary [..., %d)",
nextPos + DataHeaderSize, txnTailPos)}
}
err := dh.Load(r, nextPos)
......@@ -649,13 +643,14 @@ func (dh *DataHeader) loadNext(r io.ReaderAt, txnh *TxnHeader) error {
}
if dh.Tid != txnh.Tid {
return decodeErr(dh, "data.tid != txn.Tid") // XXX
return checkErr(dh, "tid mismatch: %s -> %s", txnh.Tid, dh.Tid)
}
if dh.TxnPos != txnh.Pos {
return decodeErr(dh, "data.txnPos != txn.Pos") // XXX
return checkErr(dh, "txn position not pointing back: %d", dh.TxnPos)
}
if dh.Pos + dh.Len() > txnTailPos {
return decodeErr(dh, "data record overlaps txn boundary") // XXX
return checkErr(dh, "data record [..., %d) overlaps txn boundary [..., %d)",
dh.Pos + dh.Len(), txnTailPos)
}
return nil
......
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