package repository import ( "context" "encoding/json" "io" "sync" "time" "github.com/restic/restic/internal" "github.com/restic/restic/internal/errors" "github.com/restic/restic/internal/debug" ) // Index holds a lookup table for id -> pack. type Index struct { m sync.Mutex pack map[restic.BlobHandle][]indexEntry final bool // set to true for all indexes read from the backend ("finalized") id restic.ID // set to the ID of the index when it's finalized supersedes restic.IDs created time.Time } type indexEntry struct { packID restic.ID offset uint length uint } // NewIndex returns a new index. func NewIndex() *Index { return &Index{ pack: make(map[restic.BlobHandle][]indexEntry), created: time.Now(), } } func (idx *Index) store(blob restic.PackedBlob) { newEntry := indexEntry{ packID: blob.PackID, offset: blob.Offset, length: blob.Length, } h := restic.BlobHandle{ID: blob.ID, Type: blob.Type} idx.pack[h] = append(idx.pack[h], newEntry) } // Final returns true iff the index is already written to the repository, it is // finalized. func (idx *Index) Final() bool { idx.m.Lock() defer idx.m.Unlock() return idx.final } const ( indexMinBlobs = 20 indexMaxBlobs = 2000 indexMinAge = 2 * time.Minute indexMaxAge = 15 * time.Minute ) // IndexFull returns true iff the index is "full enough" to be saved as a preliminary index. var IndexFull = func(idx *Index) bool { idx.m.Lock() defer idx.m.Unlock() debug.Log("checking whether index %p is full", idx) packs := len(idx.pack) age := time.Now().Sub(idx.created) if age > indexMaxAge { debug.Log("index %p is old enough", idx, age) return true } if packs < indexMinBlobs || age < indexMinAge { debug.Log("index %p only has %d packs or is too young (%v)", idx, packs, age) return false } if packs > indexMaxBlobs { debug.Log("index %p has %d packs", idx, packs) return true } debug.Log("index %p is not full", idx) return false } // Store remembers the id and pack in the index. An existing entry will be // silently overwritten. func (idx *Index) Store(blob restic.PackedBlob) { idx.m.Lock() defer idx.m.Unlock() if idx.final { panic("store new item in finalized index") } debug.Log("%v", blob) idx.store(blob) } // Lookup queries the index for the blob ID and returns a restic.PackedBlob. func (idx *Index) Lookup(id restic.ID, tpe restic.BlobType) (blobs []restic.PackedBlob, err error) { idx.m.Lock() defer idx.m.Unlock() h := restic.BlobHandle{ID: id, Type: tpe} if packs, ok := idx.pack[h]; ok { blobs = make([]restic.PackedBlob, 0, len(packs)) for _, p := range packs { debug.Log("id %v found in pack %v at %d, length %d", id.Str(), p.packID.Str(), p.offset, p.length) blob := restic.PackedBlob{ Blob: restic.Blob{ Type: tpe, Length: p.length, ID: id, Offset: p.offset, }, PackID: p.packID, } blobs = append(blobs, blob) } return blobs, nil } debug.Log("id %v not found", id.Str()) return nil, errors.Errorf("id %v not found in index", id) } // ListPack returns a list of blobs contained in a pack. func (idx *Index) ListPack(id restic.ID) (list []restic.PackedBlob) { idx.m.Lock() defer idx.m.Unlock() for h, packList := range idx.pack { for _, entry := range packList { if entry.packID == id { list = append(list, restic.PackedBlob{ Blob: restic.Blob{ ID: h.ID, Type: h.Type, Length: entry.length, Offset: entry.offset, }, PackID: entry.packID, }) } } } return list } // Has returns true iff the id is listed in the index. func (idx *Index) Has(id restic.ID, tpe restic.BlobType) bool { _, err := idx.Lookup(id, tpe) if err == nil { return true } return false } // LookupSize returns the length of the plaintext content of the blob with the // given id. func (idx *Index) LookupSize(id restic.ID, tpe restic.BlobType) (plaintextLength uint, err error) { blobs, err := idx.Lookup(id, tpe) if err != nil { return 0, err } return uint(restic.PlaintextLength(int(blobs[0].Length))), nil } // Supersedes returns the list of indexes this index supersedes, if any. func (idx *Index) Supersedes() restic.IDs { return idx.supersedes } // AddToSupersedes adds the ids to the list of indexes superseded by this // index. If the index has already been finalized, an error is returned. func (idx *Index) AddToSupersedes(ids ...restic.ID) error { idx.m.Lock() defer idx.m.Unlock() if idx.final { return errors.New("index already finalized") } idx.supersedes = append(idx.supersedes, ids...) return nil } // Each returns a channel that yields all blobs known to the index. When the // context is cancelled, the background goroutine terminates. This blocks any // modification of the index. func (idx *Index) Each(ctx context.Context) <-chan restic.PackedBlob { idx.m.Lock() ch := make(chan restic.PackedBlob) go func() { defer idx.m.Unlock() defer func() { close(ch) }() for h, packs := range idx.pack { for _, blob := range packs { select { case <-ctx.Done(): return case ch <- restic.PackedBlob{ Blob: restic.Blob{ ID: h.ID, Type: h.Type, Offset: blob.offset, Length: blob.length, }, PackID: blob.packID, }: } } } }() return ch } // Packs returns all packs in this index func (idx *Index) Packs() restic.IDSet { idx.m.Lock() defer idx.m.Unlock() packs := restic.NewIDSet() for _, list := range idx.pack { for _, entry := range list { packs.Insert(entry.packID) } } return packs } // Count returns the number of blobs of type t in the index. func (idx *Index) Count(t restic.BlobType) (n uint) { debug.Log("counting blobs of type %v", t) idx.m.Lock() defer idx.m.Unlock() for h, list := range idx.pack { if h.Type != t { continue } n += uint(len(list)) } return } type packJSON struct { ID restic.ID `json:"id"` Blobs []blobJSON `json:"blobs"` } type blobJSON struct { ID restic.ID `json:"id"` Type restic.BlobType `json:"type"` Offset uint `json:"offset"` Length uint `json:"length"` } // generatePackList returns a list of packs. func (idx *Index) generatePackList() ([]*packJSON, error) { list := []*packJSON{} packs := make(map[restic.ID]*packJSON) for h, packedBlobs := range idx.pack { for _, blob := range packedBlobs { if blob.packID.IsNull() { panic("null pack id") } debug.Log("handle blob %v", h) if blob.packID.IsNull() { debug.Log("blob %v has no packID! (offset %v, length %v)", h, blob.offset, blob.length) return nil, errors.Errorf("unable to serialize index: pack for blob %v hasn't been written yet", h) } // see if pack is already in map p, ok := packs[blob.packID] if !ok { // else create new pack p = &packJSON{ID: blob.packID} // and append it to the list and map list = append(list, p) packs[p.ID] = p } // add blob p.Blobs = append(p.Blobs, blobJSON{ ID: h.ID, Type: h.Type, Offset: blob.offset, Length: blob.length, }) } } debug.Log("done") return list, nil } type jsonIndex struct { Supersedes restic.IDs `json:"supersedes,omitempty"` Packs []*packJSON `json:"packs"` } // Encode writes the JSON serialization of the index to the writer w. func (idx *Index) Encode(w io.Writer) error { debug.Log("encoding index") idx.m.Lock() defer idx.m.Unlock() return idx.encode(w) } // encode writes the JSON serialization of the index to the writer w. func (idx *Index) encode(w io.Writer) error { debug.Log("encoding index") list, err := idx.generatePackList() if err != nil { return err } enc := json.NewEncoder(w) idxJSON := jsonIndex{ Supersedes: idx.supersedes, Packs: list, } return enc.Encode(idxJSON) } // Finalize sets the index to final and writes the JSON serialization to w. func (idx *Index) Finalize(w io.Writer) error { debug.Log("encoding index") idx.m.Lock() defer idx.m.Unlock() idx.final = true return idx.encode(w) } // ID returns the ID of the index, if available. If the index is not yet // finalized, an error is returned. func (idx *Index) ID() (restic.ID, error) { idx.m.Lock() defer idx.m.Unlock() if !idx.final { return restic.ID{}, errors.New("index not finalized") } return idx.id, nil } // SetID sets the ID the index has been written to. This requires that // Finalize() has been called before, otherwise an error is returned. func (idx *Index) SetID(id restic.ID) error { idx.m.Lock() defer idx.m.Unlock() if !idx.final { return errors.New("index is not final") } if !idx.id.IsNull() { return errors.New("ID already set") } debug.Log("ID set to %v", id.Str()) idx.id = id return nil } // Dump writes the pretty-printed JSON representation of the index to w. func (idx *Index) Dump(w io.Writer) error { debug.Log("dumping index") idx.m.Lock() defer idx.m.Unlock() list, err := idx.generatePackList() if err != nil { return err } outer := jsonIndex{ Supersedes: idx.Supersedes(), Packs: list, } buf, err := json.MarshalIndent(outer, "", " ") if err != nil { return err } _, err = w.Write(append(buf, '\n')) if err != nil { return errors.Wrap(err, "Write") } debug.Log("done") return nil } // isErrOldIndex returns true if the error may be caused by an old index // format. func isErrOldIndex(err error) bool { if e, ok := err.(*json.UnmarshalTypeError); ok && e.Value == "array" { return true } return false } // ErrOldIndexFormat means an index with the old format was detected. var ErrOldIndexFormat = errors.New("index has old format") // DecodeIndex loads and unserializes an index from rd. func DecodeIndex(buf []byte) (idx *Index, err error) { debug.Log("Start decoding index") idxJSON := &jsonIndex{} err = json.Unmarshal(buf, idxJSON) if err != nil { debug.Log("Error %v", err) if isErrOldIndex(err) { debug.Log("index is probably old format, trying that") err = ErrOldIndexFormat } return nil, errors.Wrap(err, "Decode") } idx = NewIndex() for _, pack := range idxJSON.Packs { for _, blob := range pack.Blobs { idx.store(restic.PackedBlob{ Blob: restic.Blob{ Type: blob.Type, ID: blob.ID, Offset: blob.Offset, Length: blob.Length, }, PackID: pack.ID, }) } } idx.supersedes = idxJSON.Supersedes idx.final = true debug.Log("done") return idx, nil } // DecodeOldIndex loads and unserializes an index in the old format from rd. func DecodeOldIndex(buf []byte) (idx *Index, err error) { debug.Log("Start decoding old index") list := []*packJSON{} err = json.Unmarshal(buf, &list) if err != nil { debug.Log("Error %#v", err) return nil, errors.Wrap(err, "Decode") } idx = NewIndex() for _, pack := range list { for _, blob := range pack.Blobs { idx.store(restic.PackedBlob{ Blob: restic.Blob{ Type: blob.Type, ID: blob.ID, Offset: blob.Offset, Length: blob.Length, }, PackID: pack.ID, }) } } idx.final = true debug.Log("done") return idx, nil } // LoadIndexWithDecoder loads the index and decodes it with fn. func LoadIndexWithDecoder(ctx context.Context, repo restic.Repository, id restic.ID, fn func([]byte) (*Index, error)) (idx *Index, err error) { debug.Log("Loading index %v", id.Str()) buf, err := repo.LoadAndDecrypt(ctx, restic.IndexFile, id) if err != nil { return nil, err } idx, err = fn(buf) if err != nil { debug.Log("error while decoding index %v: %v", id, err) return nil, err } idx.id = id return idx, nil }