Golang DB.GetSnapshot方法代码示例

func ldbDropFolder(db *leveldb.DB, folder []byte) {
	runtime.GC()

	snap, err := db.GetSnapshot()
	if err != nil {
		panic(err)
	}
	defer snap.Release()

	// Remove all items related to the given folder from the device->file bucket
	start := []byte{keyTypeDevice}
	limit := []byte{keyTypeDevice + 1}
	dbi := snap.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
	for dbi.Next() {
		itemFolder := deviceKeyFolder(dbi.Key())
		if bytes.Compare(folder, itemFolder) == 0 {
			db.Delete(dbi.Key(), nil)
		}
	}
	dbi.Release()

	// Remove all items related to the given folder from the global bucket
	start = []byte{keyTypeGlobal}
	limit = []byte{keyTypeGlobal + 1}
	dbi = snap.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
	for dbi.Next() {
		itemFolder := globalKeyFolder(dbi.Key())
		if bytes.Compare(folder, itemFolder) == 0 {
			db.Delete(dbi.Key(), nil)
		}
	}
	dbi.Release()
}

func ldbWithAllFolderTruncated(db *leveldb.DB, folder []byte, fn func(device []byte, f protocol.FileInfoTruncated) bool) {
	runtime.GC()

	start := deviceKey(folder, nil, nil)                                                  // before all folder/device files
	limit := deviceKey(folder, protocol.LocalDeviceID[:], []byte{0xff, 0xff, 0xff, 0xff}) // after all folder/device files
	snap, err := db.GetSnapshot()
	if err != nil {
		panic(err)
	}
	if debugDB {
		l.Debugf("created snapshot %p", snap)
	}
	defer func() {
		if debugDB {
			l.Debugf("close snapshot %p", snap)
		}
		snap.Release()
	}()

	dbi := snap.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
	defer dbi.Release()

	for dbi.Next() {
		device := deviceKeyDevice(dbi.Key())
		var f protocol.FileInfoTruncated
		err := f.UnmarshalXDR(dbi.Value())
		if err != nil {
			panic(err)
		}
		if cont := fn(device, f); !cont {
			return
		}
	}
}

func ldbWithAllRepoTruncated(db *leveldb.DB, repo []byte, fn func(node []byte, f protocol.FileInfoTruncated) bool) {
	defer runtime.GC()

	start := nodeKey(repo, nil, nil)                                                // before all repo/node files
	limit := nodeKey(repo, protocol.LocalNodeID[:], []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() {
		node := nodeKeyNode(dbi.Key())
		var f protocol.FileInfoTruncated
		err := f.UnmarshalXDR(dbi.Value())
		if err != nil {
			panic(err)
		}
		if cont := fn(node, f); !cont {
			return
		}
	}
}

func ldbDropFolder(db *leveldb.DB, folder []byte) {
	runtime.GC()

	snap, err := db.GetSnapshot()
	if err != nil {
		panic(err)
	}
	l.Debugf("created snapshot %p", snap)
	defer func() {
		l.Debugf("close snapshot %p", snap)
		snap.Release()
	}()

	// Remove all items related to the given folder from the device->file bucket
	dbi := snap.NewIterator(util.BytesPrefix([]byte{KeyTypeDevice}), nil)
	for dbi.Next() {
		itemFolder := deviceKeyFolder(dbi.Key())
		if bytes.Compare(folder, itemFolder) == 0 {
			db.Delete(dbi.Key(), nil)
		}
	}
	dbi.Release()

	// Remove all items related to the given folder from the global bucket
	dbi = snap.NewIterator(util.BytesPrefix([]byte{KeyTypeGlobal}), nil)
	for dbi.Next() {
		itemFolder := globalKeyFolder(dbi.Key())
		if bytes.Compare(folder, itemFolder) == 0 {
			db.Delete(dbi.Key(), nil)
		}
	}
	dbi.Release()
}

func ldbListRepos(db *leveldb.DB) []string {
	defer runtime.GC()

	start := []byte{keyTypeGlobal}
	limit := []byte{keyTypeGlobal + 1}
	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()

	repoExists := make(map[string]bool)
	for dbi.Next() {
		repo := string(globalKeyRepo(dbi.Key()))
		if !repoExists[repo] {
			repoExists[repo] = true
		}
	}

	repos := make([]string, 0, len(repoExists))
	for k := range repoExists {
		repos = append(repos, k)
	}

	sort.Strings(repos)
	return repos
}

func ldbListFolders(db *leveldb.DB) []string {
	runtime.GC()

	snap, err := db.GetSnapshot()
	if err != nil {
		panic(err)
	}
	l.Debugf("created snapshot %p", snap)
	defer func() {
		l.Debugf("close snapshot %p", snap)
		snap.Release()
	}()

	dbi := snap.NewIterator(util.BytesPrefix([]byte{KeyTypeGlobal}), nil)
	defer dbi.Release()

	folderExists := make(map[string]bool)
	for dbi.Next() {
		folder := string(globalKeyFolder(dbi.Key()))
		if !folderExists[folder] {
			folderExists[folder] = true
		}
	}

	folders := make([]string, 0, len(folderExists))
	for k := range folderExists {
		folders = append(folders, k)
	}

	sort.Strings(folders)
	return folders
}

func ldbDropRepo(db *leveldb.DB, repo []byte) {
	defer runtime.GC()

	snap, err := db.GetSnapshot()
	if err != nil {
		panic(err)
	}
	defer snap.Release()

	// Remove all items related to the given repo from the node->file bucket
	start := []byte{keyTypeNode}
	limit := []byte{keyTypeNode + 1}
	dbi := snap.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
	for dbi.Next() {
		itemRepo := nodeKeyRepo(dbi.Key())
		if bytes.Compare(repo, itemRepo) == 0 {
			db.Delete(dbi.Key(), nil)
		}
	}
	dbi.Release()

	// Remove all items related to the given repo from the global bucket
	start = []byte{keyTypeGlobal}
	limit = []byte{keyTypeGlobal + 1}
	dbi = snap.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
	for dbi.Next() {
		itemRepo := globalKeyRepo(dbi.Key())
		if bytes.Compare(repo, itemRepo) == 0 {
			db.Delete(dbi.Key(), nil)
		}
	}
	dbi.Release()
}

func clearItems(db *leveldb.DB) error {
	snap, err := db.GetSnapshot()
	if err != nil {
		return err
	}
	defer snap.Release()

	// Iterate over k2

	it := snap.NewIterator(util.BytesPrefix([]byte{1}), nil)
	defer it.Release()

	batch := new(leveldb.Batch)
	for it.Next() {
		k1 := it.Key()
		k2 := it.Value()

		// k2 should exist
		_, err := snap.Get(k2, nil)
		if err != nil {
			return err
		}

		// Delete the k1 => k2 mapping first
		batch.Delete(k1)
		// Then the k2 => data mapping
		batch.Delete(k2)
	}
	if testing.Verbose() {
		log.Printf("batch write (clear) %p", batch)
	}
	return db.Write(batch, nil)
}

func ldbWithHave(db *leveldb.DB, folder, device []byte, truncate bool, fn Iterator) {
	start := deviceKey(folder, device, nil)                            // before all folder/device files
	limit := deviceKey(folder, device, []byte{0xff, 0xff, 0xff, 0xff}) // after all folder/device files
	snap, err := db.GetSnapshot()
	if err != nil {
		panic(err)
	}
	if debugDB {
		l.Debugf("created snapshot %p", snap)
	}
	defer func() {
		if debugDB {
			l.Debugf("close snapshot %p", snap)
		}
		snap.Release()
	}()

	dbi := snap.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
	defer dbi.Release()

	for dbi.Next() {
		f, err := unmarshalTrunc(dbi.Value(), truncate)
		if err != nil {
			panic(err)
		}
		if cont := fn(f); !cont {
			return
		}
	}
}

func clearItems(db *leveldb.DB) error {
	snap, err := db.GetSnapshot()
	if err != nil {
		return err
	}
	defer snap.Release()

	// Iterate from the start of k2 space to the end
	it := snap.NewIterator(&util.Range{Start: []byte{2}, Limit: []byte{2, 0xff, 0xff, 0xff, 0xff}}, nil)
	defer it.Release()

	batch := &leveldb.Batch{}
	for it.Next() {
		k2 := it.Key()
		k1 := it.Value()

		// k1 should exist
		_, err := snap.Get(k1, nil)
		if err != nil {
			return err
		}

		// Delete the k2 => k1 mapping first
		batch.Delete(k2)
		// Then the k1 => key mapping
		batch.Delete(k1)
	}
	return db.Write(batch, nil)
}

func ldbListFolders(db *leveldb.DB) []string {
	runtime.GC()

	start := []byte{keyTypeGlobal}
	limit := []byte{keyTypeGlobal + 1}
	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()

	folderExists := make(map[string]bool)
	for dbi.Next() {
		folder := string(globalKeyFolder(dbi.Key()))
		if !folderExists[folder] {
			folderExists[folder] = true
		}
	}

	folders := make([]string, 0, len(folderExists))
	for k := range folderExists {
		folders = append(folders, k)
	}

	sort.Strings(folders)
	return folders
}

func ldbWithGlobal(db *leveldb.DB, folder []byte, truncate bool, fn fileIterator) {
	runtime.GC()

	start := globalKey(folder, nil)
	limit := globalKey(folder, []byte{0xff, 0xff, 0xff, 0xff})
	snap, err := db.GetSnapshot()
	if err != nil {
		panic(err)
	}
	if debugDB {
		l.Debugf("created snapshot %p", snap)
	}
	defer func() {
		if debugDB {
			l.Debugf("close snapshot %p", snap)
		}
		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?")
		}
		name := globalKeyName(dbi.Key())
		fk := deviceKey(folder, vl.versions[0].device, name)
		if debugDB {
			l.Debugf("snap.Get %p %x", snap, fk)
		}
		bs, err := snap.Get(fk, nil)
		if err != nil {
			l.Debugf("folder: %q (%x)", folder, folder)
			l.Debugf("key: %q (%x)", dbi.Key(), dbi.Key())
			l.Debugf("vl: %v", vl)
			l.Debugf("vl.versions[0].device: %x", vl.versions[0].device)
			l.Debugf("name: %q (%x)", name, name)
			l.Debugf("fk: %q", fk)
			l.Debugf("fk: %x %x %x", fk[1:1+64], fk[1+64:1+64+32], fk[1+64+32:])
			panic(err)
		}

		f, err := unmarshalTrunc(bs, truncate)
		if err != nil {
			panic(err)
		}

		if cont := fn(f); !cont {
			return
		}
	}
}

func ldbCheckGlobals(db *leveldb.DB, folder []byte) {
	defer runtime.GC()

	snap, err := db.GetSnapshot()
	if err != nil {
		panic(err)
	}
	l.Debugf("created snapshot %p", snap)
	defer func() {
		l.Debugf("close snapshot %p", snap)
		snap.Release()
	}()

	start := globalKey(folder, nil)
	limit := globalKey(folder, []byte{0xff, 0xff, 0xff, 0xff})
	dbi := snap.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
	defer dbi.Release()

	batch := new(leveldb.Batch)
	l.Debugf("new batch %p", batch)

	var fk []byte
	for dbi.Next() {
		gk := dbi.Key()
		var vl versionList
		err := vl.UnmarshalXDR(dbi.Value())
		if err != nil {
			panic(err)
		}

		// Check the global version list for consistency. An issue in previous
		// versions of goleveldb could result in reordered writes so that
		// there are global entries pointing to no longer existing files. Here
		// we find those and clear them out.

		name := globalKeyName(gk)
		var newVL versionList
		for _, version := range vl.versions {
			fk = deviceKeyInto(fk[:cap(fk)], folder, version.device, name)
			l.Debugf("snap.Get %p %x", snap, fk)
			_, err := snap.Get(fk, nil)
			if err == leveldb.ErrNotFound {
				continue
			}
			if err != nil {
				panic(err)
			}
			newVL.versions = append(newVL.versions, version)
		}

		if len(newVL.versions) != len(vl.versions) {
			l.Infof("db repair: rewriting global version list for %x %x", gk[1:1+64], gk[1+64:])
			batch.Put(dbi.Key(), newVL.MustMarshalXDR())
		}
	}
	l.Debugf("db check completed for %q", folder)
	db.Write(batch, nil)
}

func ldbGetGlobal(db *leveldb.DB, folder, file []byte) protocol.FileInfo {
	k := globalKey(folder, file)
	snap, err := db.GetSnapshot()
	if err != nil {
		panic(err)
	}
	if debugDB {
		l.Debugf("created snapshot %p", snap)
	}
	defer func() {
		if debugDB {
			l.Debugf("close snapshot %p", snap)
		}
		snap.Release()
	}()

	if debugDB {
		l.Debugf("snap.Get %p %x", snap, k)
	}
	bs, err := snap.Get(k, nil)
	if err == leveldb.ErrNotFound {
		return protocol.FileInfo{}
	}
	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 = deviceKey(folder, vl.versions[0].device, file)
	if debugDB {
		l.Debugf("snap.Get %p %x", snap, k)
	}
	bs, err = snap.Get(k, nil)
	if err != nil {
		panic(err)
	}

	var f protocol.FileInfo
	err = f.UnmarshalXDR(bs)
	if err != nil {
		panic(err)
	}
	return f
}

func ldbUpdate(db *leveldb.DB, repo, node []byte, fs []protocol.FileInfo) uint64 {
	defer runtime.GC()

	batch := new(leveldb.Batch)
	snap, err := db.GetSnapshot()
	if err != nil {
		panic(err)
	}
	defer snap.Release()

	var maxLocalVer uint64
	for _, f := range fs {
		name := []byte(f.Name)
		fk := nodeKey(repo, node, name)
		bs, err := snap.Get(fk, nil)
		if err == leveldb.ErrNotFound {
			if lv := ldbInsert(batch, repo, node, name, f); lv > maxLocalVer {
				maxLocalVer = lv
			}
			if f.IsInvalid() {
				ldbRemoveFromGlobal(snap, batch, repo, node, name)
			} else {
				ldbUpdateGlobal(snap, batch, repo, node, name, f.Version)
			}
			continue
		}

		var ef protocol.FileInfoTruncated
		err = ef.UnmarshalXDR(bs)
		if err != nil {
			panic(err)
		}
		// Flags might change without the version being bumped when we set the
		// invalid flag on an existing file.
		if ef.Version != f.Version || ef.Flags != f.Flags {
			if lv := ldbInsert(batch, repo, node, name, f); lv > maxLocalVer {
				maxLocalVer = lv
			}
			if f.IsInvalid() {
				ldbRemoveFromGlobal(snap, batch, repo, node, name)
			} else {
				ldbUpdateGlobal(snap, batch, repo, node, name, f.Version)
			}
		}
	}

	err = db.Write(batch, nil)
	if err != nil {
		panic(err)
	}

	return maxLocalVer
}