package fstree import ( "crypto/sha256" "errors" "io/ioutil" "os" "path" "strings" cid "github.com/nspcc-dev/neofs-api-go/pkg/container/id" objectSDK "github.com/nspcc-dev/neofs-api-go/pkg/object" ) // FSTree represents object storage as 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 os.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 *objectSDK.Address) string { return addr.ObjectID().String() + "." + addr.ContainerID().String() } func addressFromString(s string) (*objectSDK.Address, error) { ss := strings.SplitN(s, ".", 2) if len(ss) != 2 { return nil, errors.New("invalid address") } oid := objectSDK.NewID() if err := oid.Parse(ss[0]); err != nil { return nil, err } id := cid.New() if err := id.Parse(ss[1]); err != nil { return nil, err } addr := objectSDK.NewAddress() addr.SetObjectID(oid) addr.SetContainerID(id) return addr, nil } // Iterate iterates over all stored objects. func (t *FSTree) Iterate(f func(addr *objectSDK.Address, data []byte) error) error { return t.iterate(0, []string{t.RootPath}, f) } func (t *FSTree) iterate(depth int, curPath []string, f func(*objectSDK.Address, []byte) error) error { curName := strings.Join(curPath[1:], "") des, err := ioutil.ReadDir(path.Join(curPath...)) if err != 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, f) if err != nil { return err } } if depth != t.Depth { continue } addr, err := addressFromString(curName + des[i].Name()) if err != nil { continue } data, err := ioutil.ReadFile(path.Join(curPath...)) if err != nil { return err } if err := f(addr, data); err != nil { return err } } return nil } func (t *FSTree) treePath(addr *objectSDK.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 path.Join(dirs...) } // Delete removes object with the specified address from storage. func (t *FSTree) Delete(addr *objectSDK.Address) error { p, err := t.Exists(addr) if err != nil { return err } return os.Remove(p) } // Exists returns path to file with object contents if it exists in storage // and an error otherwise. func (t *FSTree) Exists(addr *objectSDK.Address) (string, error) { p := t.treePath(addr) _, err := os.Stat(p) if os.IsNotExist(err) { err = ErrFileNotFound } return p, err } // Put puts object in storage. func (t *FSTree) Put(addr *objectSDK.Address, data []byte) error { p := t.treePath(addr) if err := os.MkdirAll(path.Dir(p), t.Permissions); err != nil { return err } return ioutil.WriteFile(p, data, t.Permissions) } // Get returns object from storage by address. func (t *FSTree) Get(addr *objectSDK.Address) ([]byte, error) { p := t.treePath(addr) if _, err := os.Stat(p); os.IsNotExist(err) { return nil, ErrFileNotFound } return ioutil.ReadFile(p) }