7703dd5d7f
Consider a node `{FileName: "dir", Attribute: "xxx"}`. In case we add
a new node by path `["dir", "file.txt"]`, create a new intermediate node
with a single attribute.
`GetByPath` now also considers only nodes with a single attribute while building a path.
Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
555 lines
13 KiB
Go
555 lines
13 KiB
Go
package pilorama
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import (
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"bytes"
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"encoding/binary"
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"math/rand"
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"os"
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"path/filepath"
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"github.com/nspcc-dev/neo-go/pkg/io"
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cidSDK "github.com/nspcc-dev/neofs-sdk-go/container/id"
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"go.etcd.io/bbolt"
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)
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type boltForest struct {
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path string
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db *bbolt.DB
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}
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var (
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dataBucket = []byte{0}
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logBucket = []byte{1}
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)
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// NewBoltForest returns storage wrapper for storing operations on CRDT trees.
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//
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// Each tree is stored in a separate bucket by `CID + treeID` key.
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// All integers are stored in little-endian unless explicitly specified otherwise.
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//
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// DB schema (for a single tree):
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// timestamp is 8-byte, id is 4-byte.
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//
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// log storage (logBucket):
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// timestamp in big-endian -> log operation
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//
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// tree storage (dataBucket):
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// 't' + node (id) -> timestamp when the node first appeared
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// 'p' + node (id) -> parent (id)
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// 'm' + node (id) -> serialized meta
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// 'c' + parent (id) + child (id) -> 0/1
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func NewBoltForest(path string) ForestStorage {
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return &boltForest{path: path}
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}
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func (t *boltForest) Init() error { return nil }
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func (t *boltForest) Open() error {
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if err := os.MkdirAll(filepath.Dir(t.path), os.ModePerm); err != nil {
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return err
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}
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db, err := bbolt.Open(t.path, os.ModePerm, bbolt.DefaultOptions)
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if err != nil {
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return err
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}
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t.db = db
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return db.Update(func(tx *bbolt.Tx) error {
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_, err := tx.CreateBucketIfNotExists(dataBucket)
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if err != nil {
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return err
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}
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_, err = tx.CreateBucketIfNotExists(logBucket)
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if err != nil {
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return err
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}
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return nil
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})
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}
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func (t *boltForest) Close() error { return t.db.Close() }
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// TreeMove implements the Forest interface.
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func (t *boltForest) TreeMove(cid cidSDK.ID, treeID string, m *Move) (*LogMove, error) {
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var lm *LogMove
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return lm, t.db.Update(func(tx *bbolt.Tx) error {
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bLog, bTree, err := t.getTreeBuckets(tx, cid, treeID)
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if err != nil {
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return err
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}
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m.Time = t.getLatestTimestamp(bLog)
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if m.Child == RootID {
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m.Child = t.findSpareID(bTree)
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}
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lm, err = t.applyOperation(bLog, bTree, m)
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return err
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})
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}
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// TreeAddByPath implements the Forest interface.
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func (t *boltForest) TreeAddByPath(cid cidSDK.ID, treeID string, attr string, path []string, meta []KeyValue) ([]LogMove, error) {
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var lm []LogMove
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var key [17]byte
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err := t.db.Update(func(tx *bbolt.Tx) error {
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bLog, bTree, err := t.getTreeBuckets(tx, cid, treeID)
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if err != nil {
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return err
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}
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i, node, err := t.getPathPrefix(bTree, attr, path)
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if err != nil {
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return err
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}
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lm = make([]LogMove, len(path)-i+1)
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for j := i; j < len(path); j++ {
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lm[j-i].Move = Move{
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Parent: node,
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Meta: Meta{
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Time: t.getLatestTimestamp(bLog),
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Items: []KeyValue{{Key: attr, Value: []byte(path[j])}},
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},
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Child: t.findSpareID(bTree),
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}
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err := t.do(bLog, bTree, key[:], &lm[j-i])
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if err != nil {
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return err
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}
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node = lm[j-i].Child
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}
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lm[len(lm)-1].Move = Move{
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Parent: node,
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Meta: Meta{
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Time: t.getLatestTimestamp(bLog),
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Items: meta,
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},
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Child: t.findSpareID(bTree),
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}
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return t.do(bLog, bTree, key[:], &lm[len(lm)-1])
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})
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return lm, err
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}
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// getLatestTimestamp returns timestamp for a new operation which is guaranteed to be bigger than
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// all timestamps corresponding to already stored operations.
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// FIXME timestamp should be based on a node position in the container.
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func (t *boltForest) getLatestTimestamp(bLog *bbolt.Bucket) uint64 {
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c := bLog.Cursor()
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key, _ := c.Last()
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if len(key) == 0 {
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return 1
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}
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return binary.BigEndian.Uint64(key) + 1
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}
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// findSpareID returns random unused ID.
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func (t *boltForest) findSpareID(bTree *bbolt.Bucket) uint64 {
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id := uint64(rand.Int63())
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var key [9]byte
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key[0] = 't'
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binary.LittleEndian.PutUint64(key[1:], id)
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for {
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if bTree.Get(key[:]) == nil {
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return id
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}
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id = uint64(rand.Int63())
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binary.LittleEndian.PutUint64(key[1:], id)
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}
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}
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// TreeApply implements the Forest interface.
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func (t *boltForest) TreeApply(cid cidSDK.ID, treeID string, m *Move) error {
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return t.db.Update(func(tx *bbolt.Tx) error {
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bLog, bTree, err := t.getTreeBuckets(tx, cid, treeID)
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if err != nil {
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return err
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}
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_, err = t.applyOperation(bLog, bTree, m)
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return err
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})
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}
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func (t *boltForest) getTreeBuckets(tx *bbolt.Tx, cid cidSDK.ID, treeID string) (*bbolt.Bucket, *bbolt.Bucket, error) {
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treeRoot := bucketName(cid, treeID)
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child, err := tx.CreateBucket(treeRoot)
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if err != nil && err != bbolt.ErrBucketExists {
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return nil, nil, err
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}
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var bLog, bData *bbolt.Bucket
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if err == nil {
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if bLog, err = child.CreateBucket(logBucket); err != nil {
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return nil, nil, err
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}
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if bData, err = child.CreateBucket(dataBucket); err != nil {
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return nil, nil, err
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}
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} else {
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child = tx.Bucket(treeRoot)
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bLog = child.Bucket(logBucket)
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bData = child.Bucket(dataBucket)
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}
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return bLog, bData, nil
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}
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func (t *boltForest) applyOperation(logBucket, treeBucket *bbolt.Bucket, m *Move) (*LogMove, error) {
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var lm LogMove
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var tmp LogMove
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var cKey [17]byte
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c := logBucket.Cursor()
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key, value := c.Last()
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// 1. Undo up until the desired timestamp is here.
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for len(key) == 8 && binary.BigEndian.Uint64(key) > m.Time {
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if err := t.logFromBytes(&tmp, key, value); err != nil {
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return nil, err
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}
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if err := t.undo(&tmp.Move, &tmp, treeBucket, cKey[:]); err != nil {
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return nil, err
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}
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key, value = c.Prev()
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}
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// 2. Insert the operation.
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if len(key) != 8 || binary.BigEndian.Uint64(key) != m.Time {
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lm.Move = *m
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if err := t.do(logBucket, treeBucket, cKey[:], &lm); err != nil {
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return nil, err
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}
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}
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key, value = c.Next()
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// 3. Re-apply all other operations.
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for len(key) == 8 {
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if err := t.logFromBytes(&tmp, key, value); err != nil {
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return nil, err
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}
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if err := t.do(logBucket, treeBucket, cKey[:], &tmp); err != nil {
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return nil, err
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}
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key, value = c.Next()
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}
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return &lm, nil
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}
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func (t *boltForest) do(lb *bbolt.Bucket, b *bbolt.Bucket, key []byte, op *LogMove) error {
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shouldPut := !t.isAncestor(b, key, op.Child, op.Parent) &&
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!(op.Parent != 0 && op.Parent != TrashID && b.Get(timestampKey(key, op.Parent)) == nil)
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shouldRemove := op.Parent == TrashID
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currParent := b.Get(parentKey(key, op.Child))
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if currParent != nil { // node is already in tree
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op.HasOld = true
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op.Old.Parent = binary.LittleEndian.Uint64(currParent)
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if err := op.Old.Meta.FromBytes(b.Get(metaKey(key, op.Child))); err != nil {
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return err
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}
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}
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binary.BigEndian.PutUint64(key, op.Time)
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if err := lb.Put(key[:8], t.logToBytes(op)); err != nil {
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return err
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}
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if !shouldPut {
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return nil
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}
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if shouldRemove {
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if currParent != nil {
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p := binary.LittleEndian.Uint64(currParent)
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if err := b.Delete(childrenKey(key, op.Child, p)); err != nil {
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return err
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}
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}
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return t.removeNode(b, key, op.Child)
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}
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if currParent == nil {
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if err := b.Put(timestampKey(key, op.Child), toUint64(op.Time)); err != nil {
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return err
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}
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} else {
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if err := b.Delete(childrenKey(key, op.Child, binary.LittleEndian.Uint64(currParent))); err != nil {
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return err
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}
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}
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return t.addNode(b, key, op.Child, op.Parent, op.Meta)
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}
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// removeNode removes node keys from the tree except the children key or its parent.
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func (t *boltForest) removeNode(b *bbolt.Bucket, key []byte, node Node) error {
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if err := b.Delete(parentKey(key, node)); err != nil {
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return err
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}
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if err := b.Delete(metaKey(key, node)); err != nil {
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return err
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}
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return b.Delete(timestampKey(key, node))
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}
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// addNode adds node keys to the tree except the timestamp key.
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func (t *boltForest) addNode(b *bbolt.Bucket, key []byte, child, parent Node, meta Meta) error {
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err := b.Put(parentKey(key, child), toUint64(parent))
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if err != nil {
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return err
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}
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err = b.Put(childrenKey(key, child, parent), []byte{1})
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if err != nil {
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return err
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}
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return b.Put(metaKey(key, child), meta.Bytes())
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}
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func (t *boltForest) undo(m *Move, lm *LogMove, b *bbolt.Bucket, key []byte) error {
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if err := b.Delete(childrenKey(key, m.Child, m.Parent)); err != nil {
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return err
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}
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if !lm.HasOld {
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return t.removeNode(b, key, m.Child)
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}
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return t.addNode(b, key, m.Child, lm.Old.Parent, lm.Old.Meta)
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}
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func (t *boltForest) isAncestor(b *bbolt.Bucket, key []byte, parent, child Node) bool {
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key[0] = 'p'
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for c := child; c != parent; {
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binary.LittleEndian.PutUint64(key[1:], c)
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rawParent := b.Get(key[:9])
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if len(rawParent) != 8 {
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return false
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}
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c = binary.LittleEndian.Uint64(rawParent)
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}
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return true
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}
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// TreeGetByPath implements the Forest interface.
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func (t *boltForest) TreeGetByPath(cid cidSDK.ID, treeID string, attr string, path []string, latest bool) ([]Node, error) {
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if len(path) == 0 {
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return nil, nil
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}
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var nodes []Node
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return nodes, t.db.View(func(tx *bbolt.Tx) error {
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treeRoot := tx.Bucket(bucketName(cid, treeID))
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if treeRoot == nil {
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return ErrTreeNotFound
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}
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b := treeRoot.Bucket(dataBucket)
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i, curNode, err := t.getPathPrefix(b, attr, path[:len(path)-1])
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if err != nil {
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return err
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}
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if i < len(path)-1 {
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return nil
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}
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c := b.Cursor()
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var (
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metaKey [9]byte
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id [9]byte
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childID [9]byte
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m Meta
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maxTimestamp uint64
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)
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id[0] = 'c'
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metaKey[0] = 'm'
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binary.LittleEndian.PutUint64(id[1:], curNode)
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key, _ := c.Seek(id[:])
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for len(key) == 1+8+8 && bytes.Equal(id[:9], key[:9]) {
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child := binary.LittleEndian.Uint64(key[9:])
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copy(metaKey[1:], key[9:17])
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if m.FromBytes(b.Get(metaKey[:])) == nil && string(m.GetAttr(attr)) == path[len(path)-1] {
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if latest {
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ts := binary.LittleEndian.Uint64(b.Get(timestampKey(childID[:], child)))
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if ts >= maxTimestamp {
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nodes = append(nodes[:0], child)
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maxTimestamp = ts
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}
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} else {
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nodes = append(nodes, child)
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}
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}
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key, _ = c.Next()
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}
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return nil
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})
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}
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// TreeGetMeta implements the forest interface.
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func (t *boltForest) TreeGetMeta(cid cidSDK.ID, treeID string, nodeID Node) (Meta, Node, error) {
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key := parentKey(make([]byte, 9), nodeID)
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var m Meta
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var parentID uint64
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err := t.db.View(func(tx *bbolt.Tx) error {
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treeRoot := tx.Bucket(bucketName(cid, treeID))
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if treeRoot == nil {
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return ErrTreeNotFound
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}
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b := treeRoot.Bucket(dataBucket)
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if data := b.Get(key); len(data) == 8 {
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parentID = binary.LittleEndian.Uint64(data)
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}
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return m.FromBytes(b.Get(metaKey(key, nodeID)))
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})
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return m, parentID, err
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}
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// TreeGetChildren implements the Forest interface.
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func (t *boltForest) TreeGetChildren(cid cidSDK.ID, treeID string, nodeID Node) ([]uint64, error) {
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key := make([]byte, 9)
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key[0] = 'c'
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binary.LittleEndian.PutUint64(key[1:], nodeID)
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var children []uint64
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err := t.db.View(func(tx *bbolt.Tx) error {
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treeRoot := tx.Bucket(bucketName(cid, treeID))
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if treeRoot == nil {
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return ErrTreeNotFound
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}
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b := treeRoot.Bucket(dataBucket)
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c := b.Cursor()
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for k, _ := c.Seek(key); len(k) == 17 && binary.LittleEndian.Uint64(k[1:]) == nodeID; k, _ = c.Next() {
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children = append(children, binary.LittleEndian.Uint64(k[9:]))
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}
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return nil
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})
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return children, err
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}
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func (t *boltForest) getPathPrefix(bTree *bbolt.Bucket, attr string, path []string) (int, Node, error) {
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var key [9]byte
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c := bTree.Cursor()
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var curNode Node
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var m Meta
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loop:
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for i := range path {
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key[0] = 'c'
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binary.LittleEndian.PutUint64(key[1:], curNode)
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childKey, _ := c.Seek(key[:])
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for {
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if len(childKey) != 17 || binary.LittleEndian.Uint64(childKey[1:]) != curNode {
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break
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}
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child := binary.LittleEndian.Uint64(childKey[9:])
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if err := m.FromBytes(bTree.Get(metaKey(key[:], child))); err != nil {
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return 0, 0, err
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}
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// Internal nodes have exactly one attribute.
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if len(m.Items) == 1 && m.Items[0].Key == attr && string(m.Items[0].Value) == path[i] {
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curNode = child
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continue loop
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}
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childKey, _ = c.Next()
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}
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return i, curNode, nil
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}
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return len(path), curNode, nil
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}
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func (t *boltForest) logFromBytes(lm *LogMove, key []byte, data []byte) error {
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r := io.NewBinReaderFromBuf(data)
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lm.Child = r.ReadU64LE()
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lm.Parent = r.ReadU64LE()
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if err := lm.Meta.FromBytes(r.ReadVarBytes()); err != nil {
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return err
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}
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lm.HasOld = r.ReadBool()
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if lm.HasOld {
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lm.Old.Parent = r.ReadU64LE()
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if err := lm.Old.Meta.FromBytes(r.ReadVarBytes()); err != nil {
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return err
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}
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}
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return r.Err
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}
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func (t *boltForest) logToBytes(lm *LogMove) []byte {
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w := io.NewBufBinWriter()
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w.WriteU64LE(lm.Child)
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w.WriteU64LE(lm.Parent)
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w.WriteVarBytes(lm.Meta.Bytes())
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w.WriteBool(lm.HasOld)
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if lm.HasOld {
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w.WriteU64LE(lm.Old.Parent)
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w.WriteVarBytes(lm.Old.Meta.Bytes())
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}
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return w.Bytes()
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}
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func bucketName(cid cidSDK.ID, treeID string) []byte {
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return []byte(cid.String() + treeID)
|
|
}
|
|
|
|
// 't' + node (id) -> timestamp when the node first appeared
|
|
func timestampKey(key []byte, child Node) []byte {
|
|
key[0] = 't'
|
|
binary.LittleEndian.PutUint64(key[1:], child)
|
|
return key[:9]
|
|
}
|
|
|
|
// 'p' + node (id) -> parent (id)
|
|
func parentKey(key []byte, child Node) []byte {
|
|
key[0] = 'p'
|
|
binary.LittleEndian.PutUint64(key[1:], child)
|
|
return key[:9]
|
|
}
|
|
|
|
// 'm' + node (id) -> serialized meta
|
|
func metaKey(key []byte, child Node) []byte {
|
|
key[0] = 'm'
|
|
binary.LittleEndian.PutUint64(key[1:], child)
|
|
return key[:9]
|
|
}
|
|
|
|
// 'c' + parent (id) + child (id) -> 0/1
|
|
func childrenKey(key []byte, child, parent Node) []byte {
|
|
key[0] = 'c'
|
|
binary.LittleEndian.PutUint64(key[1:], parent)
|
|
binary.LittleEndian.PutUint64(key[9:], child)
|
|
return key[:17]
|
|
}
|
|
|
|
func toUint64(x uint64) []byte {
|
|
var a [8]byte
|
|
binary.LittleEndian.PutUint64(a[:], x)
|
|
return a[:]
|
|
}
|