68 lines
1.5 KiB
Go
68 lines
1.5 KiB
Go
package mmap
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import (
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"fmt"
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"os"
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"path/filepath"
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"github.com/anacrolix/libtorgo/metainfo"
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"launchpad.net/gommap"
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"github.com/anacrolix/torrent/mmap_span"
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)
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func TorrentData(md *metainfo.Info, location string) (mms *mmap_span.MMapSpan, err error) {
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mms = &mmap_span.MMapSpan{}
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defer func() {
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if err != nil {
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mms.Close()
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mms = nil
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}
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}()
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for _, miFile := range md.UpvertedFiles() {
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fileName := filepath.Join(append([]string{location, md.Name}, miFile.Path...)...)
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err = os.MkdirAll(filepath.Dir(fileName), 0777)
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if err != nil {
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err = fmt.Errorf("error creating data directory %q: %s", filepath.Dir(fileName), err)
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return
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}
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var file *os.File
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file, err = os.OpenFile(fileName, os.O_CREATE|os.O_RDWR, 0666)
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if err != nil {
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return
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}
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func() {
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defer file.Close()
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var fi os.FileInfo
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fi, err = file.Stat()
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if err != nil {
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return
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}
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if fi.Size() < miFile.Length {
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err = file.Truncate(miFile.Length)
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if err != nil {
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return
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}
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}
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if miFile.Length == 0 {
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// Can't mmap() regions with length 0.
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return
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}
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var mMap gommap.MMap
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mMap, err = gommap.MapRegion(file.Fd(), 0, miFile.Length, gommap.PROT_READ|gommap.PROT_WRITE, gommap.MAP_SHARED)
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if err != nil {
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err = fmt.Errorf("error mapping file %q, length %d: %s", file.Name(), miFile.Length, err)
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return
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}
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if int64(len(mMap)) != miFile.Length {
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panic("mmap has wrong length")
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}
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mms.Append(mMap)
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}()
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if err != nil {
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return
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}
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}
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return
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}
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