frostfs-node/pkg/local_object_storage/blobstor/fstree/fstree.go

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package fstree
import (
"crypto/sha256"
"errors"
"fmt"
"io/fs"
"os"
"path/filepath"
"strings"
"github.com/nspcc-dev/neofs-node/pkg/util"
cid "github.com/nspcc-dev/neofs-sdk-go/container/id"
oid "github.com/nspcc-dev/neofs-sdk-go/object/id"
)
// FSTree represents an object storage as a filesystem tree.
type FSTree struct {
Info
Depth int
DirNameLen int
}
// Info groups the information about file storage.
type Info struct {
// Permission bits of the root directory.
Permissions fs.FileMode
// Full path to the root directory.
RootPath string
}
const (
// DirNameLen is how many bytes is used to group keys into directories.
DirNameLen = 1 // in bytes
// MaxDepth is maximum depth of nested directories.
MaxDepth = (sha256.Size - 1) / DirNameLen
)
// ErrFileNotFound is returned when file is missing.
var ErrFileNotFound = errors.New("file not found")
func stringifyAddress(addr oid.Address) string {
return addr.Object().EncodeToString() + "." + addr.Container().EncodeToString()
}
func addressFromString(s string) (*oid.Address, error) {
ss := strings.SplitN(s, ".", 2)
if len(ss) != 2 {
return nil, errors.New("invalid address")
}
var obj oid.ID
if err := obj.DecodeString(ss[0]); err != nil {
return nil, err
}
var cnr cid.ID
if err := cnr.DecodeString(ss[1]); err != nil {
return nil, err
}
var addr oid.Address
addr.SetObject(obj)
addr.SetContainer(cnr)
return &addr, nil
}
// IterationPrm contains iteraction parameters.
type IterationPrm struct {
handler func(addr oid.Address, data []byte) error
ignoreErrors bool
}
// WithHandler sets a function to call on each object.
func (p *IterationPrm) WithHandler(f func(addr oid.Address, data []byte) error) {
p.handler = f
}
// WithIgnoreErrors sets a flag indicating whether errors should be ignored.
func (p *IterationPrm) WithIgnoreErrors(ignore bool) {
p.ignoreErrors = ignore
}
// Iterate iterates over all stored objects.
func (t *FSTree) Iterate(prm IterationPrm) error {
return t.iterate(0, []string{t.RootPath}, prm)
}
func (t *FSTree) iterate(depth int, curPath []string, prm IterationPrm) error {
curName := strings.Join(curPath[1:], "")
des, err := os.ReadDir(filepath.Join(curPath...))
if err != nil {
if prm.ignoreErrors {
return nil
}
return err
}
isLast := depth >= t.Depth
l := len(curPath)
curPath = append(curPath, "")
for i := range des {
curPath[l] = des[i].Name()
if !isLast && des[i].IsDir() {
err := t.iterate(depth+1, curPath, prm)
if err != nil {
// Must be error from handler in case errors are ignored.
// Need to report.
return err
}
}
if depth != t.Depth {
continue
}
addr, err := addressFromString(curName + des[i].Name())
if err != nil {
continue
}
data, err := os.ReadFile(filepath.Join(curPath...))
if err != nil {
if prm.ignoreErrors {
continue
}
return err
}
if err := prm.handler(*addr, data); err != nil {
// Error occurred in handler, outside of our scope, needs to be reported.
return err
}
}
return nil
}
func (t *FSTree) treePath(addr oid.Address) string {
sAddr := stringifyAddress(addr)
dirs := make([]string, 0, t.Depth+1+1) // 1 for root, 1 for file
dirs = append(dirs, t.RootPath)
for i := 0; i < t.Depth; i++ {
dirs = append(dirs, sAddr[:t.DirNameLen])
sAddr = sAddr[t.DirNameLen:]
}
dirs = append(dirs, sAddr)
return filepath.Join(dirs...)
}
// Delete removes the object with the specified address from the storage.
func (t *FSTree) Delete(addr oid.Address) error {
p, err := t.Exists(addr)
if err != nil {
return err
}
return os.Remove(p)
}
// Exists returns the path to the file with object contents if it exists in the storage
// and an error otherwise.
func (t *FSTree) Exists(addr oid.Address) (string, error) {
p := t.treePath(addr)
_, err := os.Stat(p)
if os.IsNotExist(err) {
err = ErrFileNotFound
}
return p, err
}
// Put puts an object in the storage.
func (t *FSTree) Put(addr oid.Address, data []byte) error {
p := t.treePath(addr)
if err := util.MkdirAllX(filepath.Dir(p), t.Permissions); err != nil {
return err
}
return os.WriteFile(p, data, t.Permissions)
}
// PutStream puts executes handler on a file opened for write.
func (t *FSTree) PutStream(addr oid.Address, handler func(*os.File) error) error {
p := t.treePath(addr)
if err := util.MkdirAllX(filepath.Dir(p), t.Permissions); err != nil {
return err
}
f, err := os.OpenFile(p, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, t.Permissions)
if err != nil {
return err
}
defer f.Close()
return handler(f)
}
// Get returns an object from the storage by address.
func (t *FSTree) Get(addr oid.Address) ([]byte, error) {
p := t.treePath(addr)
if _, err := os.Stat(p); os.IsNotExist(err) {
return nil, ErrFileNotFound
}
return os.ReadFile(p)
}
// NumberOfObjects walks the file tree rooted at FSTree's root
// and returns number of stored objects.
func (t *FSTree) NumberOfObjects() (uint64, error) {
var counter uint64
// it is simpler to just consider every file
// that is not directory as an object
err := filepath.WalkDir(t.RootPath,
func(_ string, d fs.DirEntry, _ error) error {
if !d.IsDir() {
counter++
}
return nil
},
)
if err != nil {
return 0, fmt.Errorf("could not walk through %s directory: %w", t.RootPath, err)
}
return counter, nil
}