package repository import ( "context" "crypto/sha256" "io" "os" "restic" "sync" "restic/errors" "restic/hashing" "restic/crypto" "restic/debug" "restic/fs" "restic/pack" ) // Saver implements saving data in a backend. type Saver interface { Save(context.Context, restic.Handle, io.Reader) error } // Packer holds a pack.Packer together with a hash writer. type Packer struct { *pack.Packer hw *hashing.Writer tmpfile *os.File } // packerManager keeps a list of open packs and creates new on demand. type packerManager struct { be Saver key *crypto.Key pm sync.Mutex packers []*Packer pool sync.Pool } const minPackSize = 4 * 1024 * 1024 const maxPackSize = 16 * 1024 * 1024 const maxPackers = 200 // newPackerManager returns an new packer manager which writes temporary files // to a temporary directory func newPackerManager(be Saver, key *crypto.Key) *packerManager { return &packerManager{ be: be, key: key, pool: sync.Pool{ New: func() interface{} { return make([]byte, (minPackSize+maxPackSize)/2) }, }, } } // findPacker returns a packer for a new blob of size bytes. Either a new one is // created or one is returned that already has some blobs. func (r *packerManager) findPacker(size uint) (packer *Packer, err error) { r.pm.Lock() defer r.pm.Unlock() // search for a suitable packer if len(r.packers) > 0 { debug.Log("searching packer for %d bytes\n", size) for i, p := range r.packers { if p.Packer.Size()+size < maxPackSize { debug.Log("found packer %v", p) // remove from list r.packers = append(r.packers[:i], r.packers[i+1:]...) return p, nil } } } // no suitable packer found, return new debug.Log("create new pack for %d bytes", size) tmpfile, err := fs.TempFile("", "restic-temp-pack-") if err != nil { return nil, errors.Wrap(err, "fs.TempFile") } hw := hashing.NewWriter(tmpfile, sha256.New()) p := pack.NewPacker(r.key, hw) packer = &Packer{ Packer: p, hw: hw, tmpfile: tmpfile, } return packer, nil } // insertPacker appends p to s.packs. func (r *packerManager) insertPacker(p *Packer) { r.pm.Lock() defer r.pm.Unlock() r.packers = append(r.packers, p) debug.Log("%d packers\n", len(r.packers)) } // savePacker stores p in the backend. func (r *Repository) savePacker(p *Packer) error { debug.Log("save packer with %d blobs (%d bytes)\n", p.Packer.Count(), p.Packer.Size()) _, err := p.Packer.Finalize() if err != nil { return err } _, err = p.tmpfile.Seek(0, 0) if err != nil { return errors.Wrap(err, "Seek") } id := restic.IDFromHash(p.hw.Sum(nil)) h := restic.Handle{Type: restic.DataFile, Name: id.String()} err = r.be.Save(context.TODO(), h, p.tmpfile) if err != nil { debug.Log("Save(%v) error: %v", h, err) return err } debug.Log("saved as %v", h) err = p.tmpfile.Close() if err != nil { return errors.Wrap(err, "close tempfile") } err = fs.RemoveIfExists(p.tmpfile.Name()) if err != nil { return errors.Wrap(err, "Remove") } // update blobs in the index for _, b := range p.Packer.Blobs() { debug.Log(" updating blob %v to pack %v", b.ID.Str(), id.Str()) r.idx.Store(restic.PackedBlob{ Blob: restic.Blob{ Type: b.Type, ID: b.ID, Offset: b.Offset, Length: uint(b.Length), }, PackID: id, }) } return nil } // countPacker returns the number of open (unfinished) packers. func (r *packerManager) countPacker() int { r.pm.Lock() defer r.pm.Unlock() return len(r.packers) }