metainfo/metainfo.go

   1 package metainfo
   2
   3 import (
   4         "crypto/sha1"
   5         "github.com/anacrolix/libtorgo/bencode"
   6         "io"
   7         "os"
   8 )
   9
  10 // Information specific to a single file inside the MetaInfo structure.
  11 type FileInfo struct {
  12         Length int64    `bencode:"length"`
  13         Path   []string `bencode:"path"`
  14 }
  15
  16 // Load a MetaInfo from an io.Reader. Returns a non-nil error in case of
  17 // failure.
  18 func Load(r io.Reader) (*MetaInfo, error) {
  19         var mi MetaInfo
  20         d := bencode.NewDecoder(r)
  21         err := d.Decode(&mi)
  22         if err != nil {
  23                 return nil, err
  24         }
  25         return &mi, nil
  26 }
  27
  28 // Convenience function for loading a MetaInfo from a file.
  29 func LoadFromFile(filename string) (*MetaInfo, error) {
  30         f, err := os.Open(filename)
  31         if err != nil {
  32                 return nil, err
  33         }
  34         defer f.Close()
  35         return Load(f)
  36 }
  37
  38 // The info dictionary.
  39 type Info struct {
  40         PieceLength int64      `bencode:"piece length"`
  41         Pieces      []byte     `bencode:"pieces"`
  42         Name        string     `bencode:"name"`
  43         Length      int64      `bencode:"length,omitempty"`
  44         Private     bool       `bencode:"private,omitempty"`
  45         Files       []FileInfo `bencode:"files,omitempty"`
  46 }
  47
  48 // The info dictionary with its hash and raw bytes exposed, as these are
  49 // important to Bittorrent.
  50 type InfoEx struct {
  51         Info
  52         Hash  []byte
  53         Bytes []byte
  54 }
  55
  56 func (this *InfoEx) UnmarshalBencode(data []byte) error {
  57         this.Bytes = make([]byte, 0, len(data))
  58         this.Bytes = append(this.Bytes, data...)
  59         h := sha1.New()
  60         h.Write(this.Bytes)
  61         this.Hash = h.Sum(this.Hash)
  62         return bencode.Unmarshal(data, &this.Info)
  63 }
  64
  65 func (this *InfoEx) MarshalBencode() ([]byte, error) {
  66         return bencode.Marshal(&this.Info)
  67 }
  68
  69 type MetaInfo struct {
  70         Info         InfoEx      `bencode:"info"`
  71         Announce     string      `bencode:"announce"`
  72         AnnounceList [][]string  `bencode:"announce-list,omitempty"`
  73         CreationDate int64       `bencode:"creation date,omitempty"`
  74         Comment      string      `bencode:"comment,omitempty"`
  75         CreatedBy    string      `bencode:"created by,omitempty"`
  76         Encoding     string      `bencode:"encoding,omitempty"`
  77         URLList      interface{} `bencode:"url-list,omitempty"`
  78 }