syncthing/files/leveldb.go

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package files
import (
"bytes"
"sort"
"github.com/calmh/syncthing/lamport"
"github.com/calmh/syncthing/protocol"
"github.com/syndtr/goleveldb/leveldb"
"github.com/syndtr/goleveldb/leveldb/iterator"
"github.com/syndtr/goleveldb/leveldb/opt"
"github.com/syndtr/goleveldb/leveldb/util"
)
const (
keyTypeNode = iota
keyTypeGlobal
)
type fileVersion struct {
version uint64
node []byte
}
type versionList struct {
versions []fileVersion
}
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type fileList []protocol.FileInfo
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func (l fileList) Len() int {
return len(l)
}
func (l fileList) Swap(a, b int) {
l[a], l[b] = l[b], l[a]
}
func (l fileList) Less(a, b int) bool {
return l[a].Name < l[b].Name
}
type dbReader interface {
Get([]byte, *opt.ReadOptions) ([]byte, error)
}
type dbWriter interface {
Put([]byte, []byte)
Delete([]byte)
}
/*
keyTypeNode (1 byte)
repository (64 bytes)
node (32 bytes)
name (variable size)
|
scanner.File
keyTypeGlobal (1 byte)
repository (64 bytes)
name (variable size)
|
[]fileVersion (sorted)
*/
func nodeKey(repo, node, file []byte) []byte {
k := make([]byte, 1+64+32+len(file))
k[0] = keyTypeNode
copy(k[1:], []byte(repo))
copy(k[1+64:], node[:])
copy(k[1+64+32:], []byte(file))
return k
}
func globalKey(repo, file []byte) []byte {
k := make([]byte, 1+64+len(file))
k[0] = keyTypeGlobal
copy(k[1:], []byte(repo))
copy(k[1+64:], []byte(file))
return k
}
func nodeKeyName(key []byte) []byte {
return key[1+64+32:]
}
func globalKeyName(key []byte) []byte {
return key[1+64:]
}
type deletionHandler func(db dbReader, batch dbWriter, repo, node, name []byte, dbi iterator.Iterator) bool
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type fileIterator func(f protocol.FileInfo) bool
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func ldbGenericReplace(db *leveldb.DB, repo, node []byte, fs []protocol.FileInfo, deleteFn deletionHandler) bool {
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sort.Sort(fileList(fs)) // sort list on name, same as on disk
start := nodeKey(repo, node, nil) // before all repo/node files
limit := nodeKey(repo, node, []byte{0xff, 0xff, 0xff, 0xff}) // after all repo/node files
batch := new(leveldb.Batch)
snap, err := db.GetSnapshot()
if err != nil {
panic(err)
}
defer snap.Release()
dbi := snap.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
defer dbi.Release()
moreDb := dbi.Next()
fsi := 0
changed := false
for {
var newName, oldName []byte
moreFs := fsi < len(fs)
if !moreDb && !moreFs {
break
}
if !moreFs && deleteFn == nil {
// We don't have any more updated files to process and deletion
// has not been requested, so we can exit early
break
}
if moreFs {
newName = []byte(fs[fsi].Name)
}
if moreDb {
oldName = nodeKeyName(dbi.Key())
}
cmp := bytes.Compare(newName, oldName)
if debug {
l.Debugf("generic replace; repo=%q node=%x moreFs=%v moreDb=%v cmp=%d newName=%q oldName=%q", repo, node, moreFs, moreDb, cmp, newName, oldName)
}
switch {
case moreFs && (!moreDb || cmp == -1):
changed = true
// Disk is missing this file. Insert it.
ldbInsert(batch, repo, node, newName, fs[fsi])
ldbUpdateGlobal(snap, batch, repo, node, newName, fs[fsi].Version)
fsi++
case cmp == 0:
// File exists on both sides - compare versions.
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var ef protocol.FileInfo
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ef.UnmarshalXDR(dbi.Value())
if fs[fsi].Version > ef.Version {
ldbInsert(batch, repo, node, newName, fs[fsi])
ldbUpdateGlobal(snap, batch, repo, node, newName, fs[fsi].Version)
changed = true
}
// Iterate both sides.
fsi++
moreDb = dbi.Next()
case moreDb && (!moreFs || cmp == 1):
if deleteFn != nil {
if deleteFn(snap, batch, repo, node, oldName, dbi) {
changed = true
}
}
moreDb = dbi.Next()
}
}
err = db.Write(batch, nil)
if err != nil {
panic(err)
}
return changed
}
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func ldbReplace(db *leveldb.DB, repo, node []byte, fs []protocol.FileInfo) bool {
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return ldbGenericReplace(db, repo, node, fs, func(db dbReader, batch dbWriter, repo, node, name []byte, dbi iterator.Iterator) bool {
// Disk has files that we are missing. Remove it.
if debug {
l.Debugf("delete; repo=%q node=%x name=%q", repo, node, name)
}
batch.Delete(dbi.Key())
ldbRemoveFromGlobal(db, batch, repo, node, name)
return true
})
}
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func ldbReplaceWithDelete(db *leveldb.DB, repo, node []byte, fs []protocol.FileInfo) bool {
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return ldbGenericReplace(db, repo, node, fs, func(db dbReader, batch dbWriter, repo, node, name []byte, dbi iterator.Iterator) bool {
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var f protocol.FileInfo
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err := f.UnmarshalXDR(dbi.Value())
if err != nil {
panic(err)
}
if !protocol.IsDeleted(f.Flags) {
if debug {
l.Debugf("mark deleted; repo=%q node=%x name=%q", repo, node, name)
}
f.Blocks = nil
f.Version = lamport.Default.Tick(f.Version)
f.Flags |= protocol.FlagDeleted
batch.Put(dbi.Key(), f.MarshalXDR())
ldbUpdateGlobal(db, batch, repo, node, nodeKeyName(dbi.Key()), f.Version)
return true
}
return false
})
}
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func ldbUpdate(db *leveldb.DB, repo, node []byte, fs []protocol.FileInfo) bool {
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batch := new(leveldb.Batch)
snap, err := db.GetSnapshot()
if err != nil {
panic(err)
}
defer snap.Release()
for _, f := range fs {
name := []byte(f.Name)
fk := nodeKey(repo, node, name)
bs, err := snap.Get(fk, nil)
if err == leveldb.ErrNotFound {
ldbInsert(batch, repo, node, name, f)
ldbUpdateGlobal(snap, batch, repo, node, name, f.Version)
continue
}
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var ef protocol.FileInfo
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err = ef.UnmarshalXDR(bs)
if err != nil {
panic(err)
}
if ef.Version != f.Version {
ldbInsert(batch, repo, node, name, f)
ldbUpdateGlobal(snap, batch, repo, node, name, f.Version)
}
}
err = db.Write(batch, nil)
if err != nil {
panic(err)
}
return true
}
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func ldbInsert(batch dbWriter, repo, node, name []byte, file protocol.FileInfo) {
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if debug {
l.Debugf("insert; repo=%q node=%x %v", repo, node, file)
}
nk := nodeKey(repo, node, name)
batch.Put(nk, file.MarshalXDR())
}
// ldbUpdateGlobal adds this node+version to the version list for the given
// file. If the node is already present in the list, the version is updated.
// If the file does not have an entry in the global list, it is created.
func ldbUpdateGlobal(db dbReader, batch dbWriter, repo, node, file []byte, version uint64) bool {
if debug {
l.Debugf("update global; repo=%q node=%x file=%q version=%d", repo, node, file, version)
}
gk := globalKey(repo, file)
svl, err := db.Get(gk, nil)
if err != nil && err != leveldb.ErrNotFound {
panic(err)
}
var fl versionList
nv := fileVersion{
node: node,
version: version,
}
if svl != nil {
err = fl.UnmarshalXDR(svl)
if err != nil {
panic(err)
}
for i := range fl.versions {
if bytes.Compare(fl.versions[i].node, node) == 0 {
if fl.versions[i].version == version {
// No need to do anything
return false
}
fl.versions = append(fl.versions[:i], fl.versions[i+1:]...)
break
}
}
}
for i := range fl.versions {
if fl.versions[i].version <= version {
t := append(fl.versions, fileVersion{})
copy(t[i+1:], t[i:])
t[i] = nv
fl.versions = t
goto done
}
}
fl.versions = append(fl.versions, nv)
done:
batch.Put(gk, fl.MarshalXDR())
return true
}
// ldbRemoveFromGlobal removes the node from the global version list for the
// given file. If the version list is empty after this, the file entry is
// removed entirely.
func ldbRemoveFromGlobal(db dbReader, batch dbWriter, repo, node, file []byte) {
if debug {
l.Debugf("remove from global; repo=%q node=%x file=%q", repo, node, file)
}
gk := globalKey(repo, file)
svl, err := db.Get(gk, nil)
if err != nil {
panic(err)
}
var fl versionList
err = fl.UnmarshalXDR(svl)
if err != nil {
panic(err)
}
for i := range fl.versions {
if bytes.Compare(fl.versions[i].node, node) == 0 {
fl.versions = append(fl.versions[:i], fl.versions[i+1:]...)
break
}
}
if len(fl.versions) == 0 {
batch.Delete(gk)
} else {
batch.Put(gk, fl.MarshalXDR())
}
}
func ldbWithHave(db *leveldb.DB, repo, node []byte, fn fileIterator) {
start := nodeKey(repo, node, nil) // before all repo/node files
limit := nodeKey(repo, node, []byte{0xff, 0xff, 0xff, 0xff}) // after all repo/node files
snap, err := db.GetSnapshot()
if err != nil {
panic(err)
}
defer snap.Release()
dbi := snap.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
defer dbi.Release()
for dbi.Next() {
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var f protocol.FileInfo
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err := f.UnmarshalXDR(dbi.Value())
if err != nil {
panic(err)
}
if cont := fn(f); !cont {
return
}
}
}
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func ldbGet(db *leveldb.DB, repo, node, file []byte) protocol.FileInfo {
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nk := nodeKey(repo, node, file)
bs, err := db.Get(nk, nil)
if err == leveldb.ErrNotFound {
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return protocol.FileInfo{}
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}
if err != nil {
panic(err)
}
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var f protocol.FileInfo
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err = f.UnmarshalXDR(bs)
if err != nil {
panic(err)
}
return f
}
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func ldbGetGlobal(db *leveldb.DB, repo, file []byte) protocol.FileInfo {
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k := globalKey(repo, file)
snap, err := db.GetSnapshot()
if err != nil {
panic(err)
}
defer snap.Release()
bs, err := snap.Get(k, nil)
if err == leveldb.ErrNotFound {
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return protocol.FileInfo{}
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}
if err != nil {
panic(err)
}
var vl versionList
err = vl.UnmarshalXDR(bs)
if err != nil {
panic(err)
}
if len(vl.versions) == 0 {
l.Debugln(k)
panic("no versions?")
}
k = nodeKey(repo, vl.versions[0].node, file)
bs, err = snap.Get(k, nil)
if err != nil {
panic(err)
}
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var f protocol.FileInfo
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err = f.UnmarshalXDR(bs)
if err != nil {
panic(err)
}
return f
}
func ldbWithGlobal(db *leveldb.DB, repo []byte, fn fileIterator) {
start := globalKey(repo, nil)
limit := globalKey(repo, []byte{0xff, 0xff, 0xff, 0xff})
snap, err := db.GetSnapshot()
if err != nil {
panic(err)
}
defer snap.Release()
dbi := snap.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
defer dbi.Release()
for dbi.Next() {
var vl versionList
err := vl.UnmarshalXDR(dbi.Value())
if err != nil {
panic(err)
}
if len(vl.versions) == 0 {
l.Debugln(dbi.Key())
panic("no versions?")
}
fk := nodeKey(repo, vl.versions[0].node, globalKeyName(dbi.Key()))
bs, err := snap.Get(fk, nil)
if err != nil {
panic(err)
}
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var f protocol.FileInfo
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err = f.UnmarshalXDR(bs)
if err != nil {
panic(err)
}
if cont := fn(f); !cont {
return
}
}
}
func ldbAvailability(db *leveldb.DB, repo, file []byte) []protocol.NodeID {
k := globalKey(repo, file)
bs, err := db.Get(k, nil)
if err == leveldb.ErrNotFound {
return nil
}
if err != nil {
panic(err)
}
var vl versionList
err = vl.UnmarshalXDR(bs)
if err != nil {
panic(err)
}
var nodes []protocol.NodeID
for _, v := range vl.versions {
if v.version != vl.versions[0].version {
break
}
var n protocol.NodeID
copy(n[:], v.node)
nodes = append(nodes, n)
}
return nodes
}
func ldbWithNeed(db *leveldb.DB, repo, node []byte, fn fileIterator) {
start := globalKey(repo, nil)
limit := globalKey(repo, []byte{0xff, 0xff, 0xff, 0xff})
snap, err := db.GetSnapshot()
if err != nil {
panic(err)
}
defer snap.Release()
dbi := snap.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
defer dbi.Release()
for dbi.Next() {
var vl versionList
err := vl.UnmarshalXDR(dbi.Value())
if err != nil {
panic(err)
}
if len(vl.versions) == 0 {
l.Debugln(dbi.Key())
panic("no versions?")
}
have := false // If we have the file, any version
need := false // If we have a lower version of the file
var haveVersion uint64
for _, v := range vl.versions {
if bytes.Compare(v.node, node) == 0 {
have = true
haveVersion = v.version
need = v.version < vl.versions[0].version
break
}
}
if need || !have {
name := globalKeyName(dbi.Key())
if debug {
l.Debugf("need repo=%q node=%x name=%q need=%v have=%v haveV=%d globalV=%d", repo, node, name, need, have, haveVersion, vl.versions[0].version)
}
fk := nodeKey(repo, vl.versions[0].node, name)
bs, err := snap.Get(fk, nil)
if err != nil {
panic(err)
}
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var gf protocol.FileInfo
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err = gf.UnmarshalXDR(bs)
if err != nil {
panic(err)
}
if protocol.IsDeleted(gf.Flags) && !have {
// We don't need deleted files that we don't have
continue
}
if cont := fn(gf); !cont {
return
}
}
}
}