forked from anacrolix/torrent
/
mmap.go
163 lines (145 loc) · 3.37 KB
/
mmap.go
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package storage
import (
"errors"
"fmt"
"io"
"os"
"path/filepath"
"github.com/anacrolix/missinggo"
"github.com/edsrzf/mmap-go"
"github.com/sickyoon/torrent/metainfo"
"github.com/sickyoon/torrent/mmap_span"
)
type mmapClientImpl struct {
baseDir string
pc PieceCompletion
}
func NewMMap(baseDir string) ClientImpl {
return NewMMapWithCompletion(baseDir, pieceCompletionForDir(baseDir))
}
func NewMMapWithCompletion(baseDir string, completion PieceCompletion) ClientImpl {
return &mmapClientImpl{
baseDir: baseDir,
pc: completion,
}
}
func (s *mmapClientImpl) OpenTorrent(info *metainfo.Info, infoHash metainfo.Hash) (t TorrentImpl, err error) {
span, err := mMapTorrent(info, s.baseDir)
t = &mmapTorrentStorage{
infoHash: infoHash,
span: span,
pc: s.pc,
}
return
}
func (s *mmapClientImpl) Close() error {
return s.pc.Close()
}
type mmapTorrentStorage struct {
infoHash metainfo.Hash
span *mmap_span.MMapSpan
pc PieceCompletionGetSetter
}
func (ts *mmapTorrentStorage) Piece(p metainfo.Piece) PieceImpl {
return mmapStoragePiece{
pc: ts.pc,
p: p,
ih: ts.infoHash,
ReaderAt: io.NewSectionReader(ts.span, p.Offset(), p.Length()),
WriterAt: missinggo.NewSectionWriter(ts.span, p.Offset(), p.Length()),
}
}
func (ts *mmapTorrentStorage) Close() error {
return ts.span.Close()
}
type mmapStoragePiece struct {
pc PieceCompletionGetSetter
p metainfo.Piece
ih metainfo.Hash
io.ReaderAt
io.WriterAt
}
func (me mmapStoragePiece) pieceKey() metainfo.PieceKey {
return metainfo.PieceKey{me.ih, me.p.Index()}
}
func (sp mmapStoragePiece) Completion() Completion {
c, err := sp.pc.Get(sp.pieceKey())
if err != nil {
panic(err)
}
return c
}
func (sp mmapStoragePiece) MarkComplete() error {
sp.pc.Set(sp.pieceKey(), true)
return nil
}
func (sp mmapStoragePiece) MarkNotComplete() error {
sp.pc.Set(sp.pieceKey(), false)
return nil
}
func mMapTorrent(md *metainfo.Info, location string) (mms *mmap_span.MMapSpan, err error) {
mms = &mmap_span.MMapSpan{}
defer func() {
if err != nil {
mms.Close()
}
}()
for _, miFile := range md.UpvertedFiles() {
fileName := filepath.Join(append([]string{location, md.Name}, miFile.Path...)...)
var mm mmap.MMap
mm, err = mmapFile(fileName, miFile.Length)
if err != nil {
err = fmt.Errorf("file %q: %s", miFile.DisplayPath(md), err)
return
}
if mm != nil {
mms.Append(mm)
}
}
return
}
func mmapFile(name string, size int64) (ret mmap.MMap, err error) {
dir := filepath.Dir(name)
err = os.MkdirAll(dir, 0777)
if err != nil {
err = fmt.Errorf("making directory %q: %s", dir, err)
return
}
var file *os.File
file, err = os.OpenFile(name, os.O_CREATE|os.O_RDWR, 0666)
if err != nil {
return
}
defer file.Close()
var fi os.FileInfo
fi, err = file.Stat()
if err != nil {
return
}
if fi.Size() < size {
// I think this is necessary on HFS+. Maybe Linux will SIGBUS too if
// you overmap a file but I'm not sure.
err = file.Truncate(size)
if err != nil {
return
}
}
if size == 0 {
// Can't mmap() regions with length 0.
return
}
intLen := int(size)
if int64(intLen) != size {
err = errors.New("size too large for system")
return
}
ret, err = mmap.MapRegion(file, intLen, mmap.RDWR, 0, 0)
if err != nil {
err = fmt.Errorf("error mapping region: %s", err)
return
}
if int64(len(ret)) != size {
panic(len(ret))
}
return
}