FedP2P/storage/bolt_piece.go

109 lines
2.0 KiB
Go

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
}