package storage import ( "encoding/binary" "io" "go.etcd.io/bbolt" "github.com/anacrolix/torrent/metainfo" ) type boltDBPiece struct { db *bbolt.DB p metainfo.Piece ih metainfo.Hash key [24]byte } var ( _ PieceImpl = (*boltDBPiece)(nil) dataBucketKey = []byte("data") ) func (me *boltDBPiece) pc() PieceCompletionGetSetter { return boltPieceCompletion{me.db} } func (me *boltDBPiece) pk() metainfo.PieceKey { return metainfo.PieceKey{me.ih, me.p.Index()} } func (me *boltDBPiece) Completion() Completion { c, err := me.pc().Get(me.pk()) switch err { case bbolt.ErrDatabaseNotOpen: return Completion{} case nil: default: panic(err) } return c } func (me *boltDBPiece) MarkComplete() error { return me.pc().Set(me.pk(), true) } func (me *boltDBPiece) MarkNotComplete() error { return me.pc().Set(me.pk(), false) } func (me *boltDBPiece) ReadAt(b []byte, off int64) (n int, err error) { err = me.db.View(func(tx *bbolt.Tx) error { db := tx.Bucket(dataBucketKey) if db == nil { return io.EOF } ci := off / chunkSize off %= chunkSize for len(b) != 0 { ck := me.chunkKey(int(ci)) _b := db.Get(ck[:]) // If the chunk is the wrong size, assume it's missing as we can't rely on the data. if len(_b) != chunkSize { return io.EOF } n1 := copy(b, _b[off:]) off = 0 ci++ b = b[n1:] n += n1 } return nil }) return } func (me *boltDBPiece) chunkKey(index int) (ret [26]byte) { copy(ret[:], me.key[:]) binary.BigEndian.PutUint16(ret[24:], uint16(index)) return } func (me *boltDBPiece) WriteAt(b []byte, off int64) (n int, err error) { err = me.db.Update(func(tx *bbolt.Tx) error { db, err := tx.CreateBucketIfNotExists(dataBucketKey) if err != nil { return err } ci := off / chunkSize off %= chunkSize for len(b) != 0 { _b := make([]byte, chunkSize) ck := me.chunkKey(int(ci)) copy(_b, db.Get(ck[:])) n1 := copy(_b[off:], b) db.Put(ck[:], _b) if n1 > len(b) { break } b = b[n1:] off = 0 ci++ n += n1 } return nil }) return }