lotus/extern/sector-storage/piece_provider.go
2021-05-20 12:49:53 +02:00

111 lines
3.1 KiB
Go

package sectorstorage
import (
"bufio"
"context"
"io"
"github.com/ipfs/go-cid"
"golang.org/x/xerrors"
"github.com/filecoin-project/go-state-types/abi"
"github.com/filecoin-project/specs-storage/storage"
"github.com/filecoin-project/lotus/extern/sector-storage/fr32"
"github.com/filecoin-project/lotus/extern/sector-storage/stores"
"github.com/filecoin-project/lotus/extern/sector-storage/storiface"
)
type Unsealer interface {
SectorsUnsealPiece(ctx context.Context, sector storage.SectorRef, offset storiface.UnpaddedByteIndex, size abi.UnpaddedPieceSize, randomness abi.SealRandomness, commd *cid.Cid) error
}
type PieceProvider struct {
storage *stores.Remote
index stores.SectorIndex
uns Unsealer
}
func NewPieceProvider(storage *stores.Remote, index stores.SectorIndex, uns Unsealer) *PieceProvider {
return &PieceProvider{
storage: storage,
index: index,
uns: uns,
}
}
func (p *PieceProvider) tryReadUnsealedPiece(ctx context.Context, sector storage.SectorRef, offset storiface.UnpaddedByteIndex, size abi.UnpaddedPieceSize) (io.ReadCloser, context.CancelFunc, error) {
// acquire a lock purely for reading unsealed sectors
ctx, cancel := context.WithCancel(ctx)
if err := p.index.StorageLock(ctx, sector.ID, storiface.FTUnsealed, storiface.FTNone); err != nil {
cancel()
return nil, nil, xerrors.Errorf("acquiring read sector lock: %w", err)
}
r, err := p.storage.Reader(ctx, sector, abi.PaddedPieceSize(offset.Padded()), size.Padded(), storiface.FTUnsealed)
if err != nil {
cancel()
return nil, nil, err
}
if r == nil {
cancel()
}
return r, cancel, nil
}
func (p *PieceProvider) ReadPiece(ctx context.Context, sector storage.SectorRef, offset storiface.UnpaddedByteIndex, size abi.UnpaddedPieceSize, ticket abi.SealRandomness, unsealed cid.Cid) (io.ReadCloser, bool, error) {
if err := offset.Valid(); err != nil {
return nil, false, xerrors.Errorf("offset is not valid: %w", err)
}
if err := size.Validate(); err != nil {
return nil, false, xerrors.Errorf("size is not a valid piece size: %w", err)
}
r, unlock, err := p.tryReadUnsealedPiece(ctx, sector, offset, size)
if err != nil {
return nil, false, err
}
var uns bool
if r == nil {
uns = true
commd := &unsealed
if unsealed == cid.Undef {
commd = nil
}
if err := p.uns.SectorsUnsealPiece(ctx, sector, offset, size, ticket, commd); err != nil {
return nil, false, xerrors.Errorf("unsealing piece: %w", err)
}
r, unlock, err = p.tryReadUnsealedPiece(ctx, sector, offset, size)
if err != nil {
return nil, true, xerrors.Errorf("read after unsealing: %w", err)
}
if r == nil {
return nil, true, xerrors.Errorf("got no reader after unsealing piece")
}
}
upr, err := fr32.NewUnpadReader(r, size.Padded())
if err != nil {
return nil, uns, xerrors.Errorf("creating unpadded reader: %w", err)
}
return &funcCloser{
Reader: bufio.NewReaderSize(upr, 127),
close: func() error {
err = r.Close()
unlock()
return err
},
}, uns, nil
}
type funcCloser struct {
io.Reader
close func() error
}
func (fc *funcCloser) Close() error { return fc.close() }