package backend import ( "bytes" "context" "fmt" "io" "github.com/cenkalti/backoff/v4" "github.com/restic/restic/internal/debug" "github.com/restic/restic/internal/errors" "github.com/restic/restic/internal/restic" ) // LoadAll reads all data stored in the backend for the handle into the given // buffer, which is truncated. If the buffer is not large enough or nil, a new // one is allocated. func LoadAll(ctx context.Context, buf []byte, be restic.Backend, h restic.Handle) ([]byte, error) { retriedInvalidData := false err := be.Load(ctx, h, 0, 0, func(rd io.Reader) error { // make sure this is idempotent, in case an error occurs this function may be called multiple times! wr := bytes.NewBuffer(buf[:0]) _, cerr := io.Copy(wr, rd) if cerr != nil { return cerr } buf = wr.Bytes() // retry loading damaged data only once. If a file fails to download correctly // the second time, then it is likely corrupted at the backend. Return the data // to the caller in that case to let it decide what to do with the data. if !retriedInvalidData && h.Type != restic.ConfigFile { id, err := restic.ParseID(h.Name) if err == nil && !restic.Hash(buf).Equal(id) { debug.Log("retry loading broken blob %v", h) retriedInvalidData = true return errors.Errorf("loadAll(%v): invalid data returned", h) } } return nil }) if err != nil { return nil, err } return buf, nil } // LimitedReadCloser wraps io.LimitedReader and exposes the Close() method. type LimitedReadCloser struct { io.Closer io.LimitedReader } // LimitReadCloser returns a new reader wraps r in an io.LimitedReader, but also // exposes the Close() method. func LimitReadCloser(r io.ReadCloser, n int64) *LimitedReadCloser { return &LimitedReadCloser{Closer: r, LimitedReader: io.LimitedReader{R: r, N: n}} } // DefaultLoad implements Backend.Load using lower-level openReader func func DefaultLoad(ctx context.Context, h restic.Handle, length int, offset int64, openReader func(ctx context.Context, h restic.Handle, length int, offset int64) (io.ReadCloser, error), fn func(rd io.Reader) error) error { if err := h.Valid(); err != nil { return backoff.Permanent(err) } if offset < 0 { return errors.New("offset is negative") } if length < 0 { return errors.Errorf("invalid length %d", length) } rd, err := openReader(ctx, h, length, offset) if err != nil { return err } err = fn(rd) if err != nil { _ = rd.Close() // ignore secondary errors closing the reader return err } return rd.Close() } type memorizedLister struct { fileInfos []restic.FileInfo tpe restic.FileType } func (m *memorizedLister) List(ctx context.Context, t restic.FileType, fn func(restic.FileInfo) error) error { if t != m.tpe { return fmt.Errorf("filetype mismatch, expected %s got %s", m.tpe, t) } for _, fi := range m.fileInfos { if ctx.Err() != nil { break } err := fn(fi) if err != nil { return err } } return ctx.Err() } func MemorizeList(ctx context.Context, be restic.Lister, t restic.FileType) (restic.Lister, error) { if _, ok := be.(*memorizedLister); ok { return be, nil } var fileInfos []restic.FileInfo err := be.List(ctx, t, func(fi restic.FileInfo) error { fileInfos = append(fileInfos, fi) return nil }) if err != nil { return nil, err } return &memorizedLister{ fileInfos: fileInfos, tpe: t, }, nil }