torrent/ratelimitreader.go

33 lines
615 B
Go

package torrent
import (
"fmt"
"io"
"time"
"golang.org/x/net/context"
"golang.org/x/time/rate"
)
type rateLimitedReader struct {
l *rate.Limiter
r io.Reader
}
func (me rateLimitedReader) Read(b []byte) (n int, err error) {
// Wait until we can read at all.
if err := me.l.WaitN(context.Background(), 1); err != nil {
panic(err)
}
// Limit the read to within the burst.
if me.l.Limit() != rate.Inf && len(b) > me.l.Burst() {
b = b[:me.l.Burst()]
}
n, err = me.r.Read(b)
// Pay the piper.
if !me.l.ReserveN(time.Now(), n-1).OK() {
panic(fmt.Sprintf("burst exceeded?: %d", n-1))
}
return
}