lotus/lib/commp/writer.go
2020-10-26 15:16:28 +01:00

114 lines
2.9 KiB
Go

package commp
import (
"bytes"
"math/bits"
"github.com/ipfs/go-cid"
"golang.org/x/xerrors"
ffi "github.com/filecoin-project/filecoin-ffi"
"github.com/filecoin-project/go-padreader"
"github.com/filecoin-project/go-state-types/abi"
"github.com/filecoin-project/lotus/api"
"github.com/filecoin-project/lotus/extern/sector-storage/ffiwrapper"
"github.com/filecoin-project/lotus/extern/sector-storage/zerocomm"
)
const commPBufPad = abi.PaddedPieceSize(8 << 20)
const CommPBuf = abi.UnpaddedPieceSize(commPBufPad - (commPBufPad / 128)) // can't use .Unpadded() for const
type Writer struct {
len int64
buf [CommPBuf]byte
leaves []cid.Cid
}
func (w *Writer) Write(p []byte) (int, error) {
n := len(p)
for len(p) > 0 {
buffered := int(w.len % int64(len(w.buf)))
toBuffer := len(w.buf) - buffered
if toBuffer > len(p) {
toBuffer = len(p)
}
copied := copy(w.buf[buffered:], p[:toBuffer])
p = p[copied:]
w.len += int64(copied)
if copied > 0 && w.len%int64(len(w.buf)) == 0 {
leaf, err := ffiwrapper.GeneratePieceCIDFromFile(abi.RegisteredSealProof_StackedDrg32GiBV1, bytes.NewReader(w.buf[:]), CommPBuf)
if err != nil {
return 0, err
}
w.leaves = append(w.leaves, leaf)
}
}
return n, nil
}
func (w *Writer) Sum() (api.DataCIDSize, error) {
// process last non-zero leaf if exists
lastLen := w.len % int64(len(w.buf))
rawLen := w.len
// process remaining bit of data
if lastLen != 0 {
if len(w.leaves) != 0 {
copy(w.buf[lastLen:], make([]byte, int(int64(CommPBuf)-lastLen)))
lastLen = int64(CommPBuf)
}
r, sz := padreader.New(bytes.NewReader(w.buf[:lastLen]), uint64(lastLen))
p, err := ffiwrapper.GeneratePieceCIDFromFile(abi.RegisteredSealProof_StackedDrg32GiBV1, r, sz)
if err != nil {
return api.DataCIDSize{}, err
}
if sz < CommPBuf { // special case for pieces smaller than 16MiB
return api.DataCIDSize{
PayloadSize: w.len,
PieceSize: sz.Padded(),
PieceCID: p,
}, nil
}
w.leaves = append(w.leaves, p)
}
// pad with zero pieces to power-of-two size
fillerLeaves := (1 << (bits.Len(uint(len(w.leaves) - 1)))) - len(w.leaves)
for i := 0; i < fillerLeaves; i++ {
w.leaves = append(w.leaves, zerocomm.ZeroPieceCommitment(CommPBuf))
}
if len(w.leaves) == 1 {
return api.DataCIDSize{
PayloadSize: rawLen,
PieceSize: abi.PaddedPieceSize(len(w.leaves)) * commPBufPad,
PieceCID: w.leaves[0],
}, nil
}
pieces := make([]abi.PieceInfo, len(w.leaves))
for i, leaf := range w.leaves {
pieces[i] = abi.PieceInfo{
Size: commPBufPad,
PieceCID: leaf,
}
}
p, err := ffi.GenerateUnsealedCID(abi.RegisteredSealProof_StackedDrg32GiBV1, pieces)
if err != nil {
return api.DataCIDSize{}, xerrors.Errorf("generating unsealed CID: %w", err)
}
return api.DataCIDSize{
PayloadSize: rawLen,
PieceSize: abi.PaddedPieceSize(len(w.leaves)) * commPBufPad,
PieceCID: p,
}, nil
}