package metainfo // this file is from https://github.com/majestrate/XD import ( "crypto/sha1" "github.com/zeebo/bencode" "io" "os" "path/filepath" ) type FilePath []string // get filepath func (f FilePath) FilePath() string { return filepath.Join(f...) } /** open file using base path */ func (f FilePath) Open(base string) (*os.File, error) { return os.OpenFile(filepath.Join(base, f.FilePath()), os.O_RDWR|os.O_CREATE, 0600) } type FileInfo struct { // length of file Length uint64 `bencode:"length"` // relative path of file Path FilePath `bencode:"path"` // md5sum Sum []byte `bencode:"md5sum,omitempty"` } // info section of torrent file type Info struct { // length of pices in bytes PieceLength uint32 `bencode:"piece length"` // piece data Pieces []byte `bencode:"pieces"` // name of root file Path string `bencode:"name"` // file metadata Files []FileInfo `bencode:"files,omitempty"` // private torrent Private *int64 `bencode:"private,omitempty"` // length of file in signle file mode Length uint64 `bencode:"length,omitempty"` // md5sum Sum []byte `bencode:"md5sum,omitempty"` } // get fileinfos from this info section func (i Info) GetFiles() (infos []FileInfo) { if i.Length > 0 { infos = append(infos, FileInfo{ Length: i.Length, Path: FilePath([]string{i.Path}), Sum: i.Sum, }) } else { infos = append(infos, i.Files...) } return } func (i Info) NumPieces() uint32 { return uint32(len(i.Pieces) / 20) } // a torrent file type TorrentFile struct { Info Info `bencode:"info"` Announce string `bencode:"announce"` AnnounceList [][]string `bencode:"announce-list"` Created uint64 `bencode:"created"` Comment []byte `bencode:"comment"` CreatedBy []byte `bencode:"created by"` Encoding []byte `bencode:"encoding"` } // get total size of files from torrent info section func (tf *TorrentFile) TotalSize() uint64 { if tf.IsSingleFile() { return tf.Info.Length } total := uint64(0) for _, f := range tf.Info.Files { total += f.Length } return total } func (tf *TorrentFile) GetAllAnnounceURLS() (l []string) { if len(tf.Announce) > 0 { l = append(l, tf.Announce) } for _, al := range tf.AnnounceList { for _, a := range al { if len(a) > 0 { l = append(l, a) } } } return } func (tf *TorrentFile) TorrentName() string { return string(tf.Info.Path) } // return true if this torrent is private otherwise return false func (tf *TorrentFile) IsPrivate() bool { return tf.Info.Private != nil && *tf.Info.Private == 1 } // calculate infohash func (tf *TorrentFile) Infohash() (ih [20]byte) { s := sha1.New() enc := bencode.NewEncoder(s) enc.Encode(&tf.Info) d := s.Sum(nil) copy(ih[:], d[:]) return } // return true if this torrent is for a single file func (tf *TorrentFile) IsSingleFile() bool { return tf.Info.Length > 0 } // bencode this file via an io.Writer func (tf *TorrentFile) Encode(w io.Writer) (err error) { enc := bencode.NewEncoder(w) err = enc.Encode(tf) return } // load from an io.Reader func (tf *TorrentFile) Decode(r io.Reader) (err error) { dec := bencode.NewDecoder(r) err = dec.Decode(tf) return }