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 gommap.MMap
mMap, err = gommap.MapRegion(file.Fd(), 0, miFile.Length, gommap.PROT_READ|gommap.PROT_WRITE, gommap.MAP_SHARED)
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
}
func fileToMmap(filename string, length int64, devZero *os.File) gommap.MMap {
osFile, err := os.Open(filename)
if err != nil {
log.Fatal(err)
}
mmapFd := osFile.Fd()
goMMap, err := gommap.MapRegion(mmapFd, 0, length, gommap.PROT_READ, gommap.MAP_PRIVATE)
if err != nil {
log.Fatal(err)
}
if int64(len(goMMap)) != length {
log.Printf("file mmap has wrong size: %#v", filename)
}
osFile.Close()
return goMMap
}