add reader

src/server/torr/Reader.go

@@ -0,0 +1,48 @@
+package torr
+
+import (
+	"io"
+
+	"github.com/anacrolix/torrent"
+	"server/torr/storage/memcacheV2"
+)
+
+type Reader struct {
+	torrent.Reader
+
+	offset int64
+
+	file  *torrent.File
+	cache *memcacheV2.Cache
+}
+
+func NewReader(file *torrent.File, cache *memcacheV2.Cache) *Reader {
+	r := new(Reader)
+	r.file = file
+	r.Reader = file.NewReader()
+	r.Reader.SetReadahead(0)
+	r.cache = cache
+	return r
+}
+
+func (r *Reader) Seek(offset int64, whence int) (n int64, err error) {
+	switch whence {
+	case io.SeekStart:
+		r.offset = offset
+	case io.SeekCurrent:
+		r.offset += offset
+	case io.SeekEnd:
+		r.offset = r.file.Length() - offset
+	}
+	n, err = r.Reader.Seek(offset, whence)
+	r.offset = n
+	r.cache.SetPos(int(n))
+	return
+}
+
+func (r *Reader) Read(p []byte) (n int, err error) {
+	n, err = r.Reader.Read(p)
+	r.offset += int64(n)
+	r.cache.SetPos(int(n))
+	return
+}