torrent/data/mmap/mmap.go

90 lines
1.9 KiB
Go

package mmap
import (
"fmt"
"os"
"path/filepath"
"github.com/edsrzf/mmap-go"
"github.com/anacrolix/torrent/metainfo"
"github.com/anacrolix/torrent/mmap_span"
)
type torrentData struct {
// Supports non-torrent specific data operations for the torrent.Data
// interface.
mmap_span.MMapSpan
completed []bool
}
func (me *torrentData) PieceComplete(piece int) bool {
return me.completed[piece]
}
func (me *torrentData) PieceCompleted(piece int) error {
me.completed[piece] = true
return nil
}
func TorrentData(md *metainfo.Info, location string) (ret *torrentData, err error) {
var 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...)...)
err = os.MkdirAll(filepath.Dir(fileName), 0777)
if err != nil {
err = fmt.Errorf("error creating data directory %q: %s", filepath.Dir(fileName), err)
return
}
var file *os.File
file, err = os.OpenFile(fileName, os.O_CREATE|os.O_RDWR, 0666)
if err != nil {
return
}
func() {
defer file.Close()
var fi os.FileInfo
fi, err = file.Stat()
if err != nil {
return
}
if fi.Size() < miFile.Length {
err = file.Truncate(miFile.Length)
if err != nil {
return
}
}
if miFile.Length == 0 {
// Can't mmap() regions with length 0.
return
}
var mMap mmap.MMap
mMap, err = mmap.MapRegion(file,
int(miFile.Length), // Probably not great on <64 bit systems.
mmap.RDWR, 0, 0)
if err != nil {
err = fmt.Errorf("error mapping file %q, length %d: %s", file.Name(), miFile.Length, err)
return
}
if int64(len(mMap)) != miFile.Length {
panic("mmap has wrong length")
}
mms.Append(mMap)
}()
if err != nil {
return
}
}
ret = &torrentData{
MMapSpan: mms,
completed: make([]bool, md.NumPieces()),
}
return
}