Use the same info bytes from a decode, for a recode

This handles strange uses of optional info fields, like private=0

diff --git a/metainfo/metainfo.go b/metainfo/metainfo.go
index 4d7c9f68db3b0576a44950febd2c2ff21dc152da..8d205792837dafb8676101a4a307920642ac100c 100644 (file)
--- a/metainfo/metainfo.go
+++ b/metainfo/metainfo.go
@@ -2,9 +2,10 @@ package metainfo
 
 import (
        "crypto/sha1"
-       "github.com/anacrolix/libtorgo/bencode"
        "io"
        "os"
+
+       "github.com/anacrolix/libtorgo/bencode"
 )
 
 // Information specific to a single file inside the MetaInfo structure.
@@ -53,16 +54,27 @@ type InfoEx struct {
        Bytes []byte
 }
 
+var (
+       _ bencode.Marshaler   = InfoEx{}
+       _ bencode.Unmarshaler = &InfoEx{}
+)
+
 func (this *InfoEx) UnmarshalBencode(data []byte) error {
        this.Bytes = make([]byte, 0, len(data))
        this.Bytes = append(this.Bytes, data...)
        h := sha1.New()
-       h.Write(this.Bytes)
-       this.Hash = h.Sum(this.Hash)
+       _, err := h.Write(this.Bytes)
+       if err != nil {
+               panic(err)
+       }
+       this.Hash = h.Sum(nil)
        return bencode.Unmarshal(data, &this.Info)
 }
 
-func (this *InfoEx) MarshalBencode() ([]byte, error) {
+func (this InfoEx) MarshalBencode() ([]byte, error) {
+       if this.Bytes != nil {
+               return this.Bytes, nil
+       }
        return bencode.Marshal(&this.Info)
 }