First step of upcoming refactor for Xray-core: Add TimeoutWrapperReader; Use DispatchLink() in Tunnel/Socks/HTTP inbounds

https://github.com/XTLS/Xray-core/pull/5067#issuecomment-3236833240

Fixes https://github.com/XTLS/Xray-core/pull/4952#issuecomment-3229878125 for client's Xray-core

common/buf/io.go

@@ -24,9 +24,46 @@ var ErrReadTimeout = errors.New("IO timeout")
 
 // TimeoutReader is a reader that returns error if Read() operation takes longer than the given timeout.
 type TimeoutReader interface {
+	Reader
 	ReadMultiBufferTimeout(time.Duration) (MultiBuffer, error)
 }
 
+type TimeoutWrapperReader struct {
+	Reader
+	mb   MultiBuffer
+	err  error
+	done chan struct{}
+}
+
+func (r *TimeoutWrapperReader) ReadMultiBuffer() (MultiBuffer, error) {
+	if r.done != nil {
+		<-r.done
+		r.done = nil
+		return r.mb, r.err
+	}
+	r.mb = nil
+	r.err = nil
+	return r.Reader.ReadMultiBuffer()
+}
+
+func (r *TimeoutWrapperReader) ReadMultiBufferTimeout(duration time.Duration) (MultiBuffer, error) {
+	if r.done == nil {
+		r.done = make(chan struct{})
+		go func() {
+			r.mb, r.err = r.Reader.ReadMultiBuffer()
+			close(r.done)
+		}()
+	}
+	time.Sleep(duration)
+	select {
+	case <-r.done:
+		r.done = nil
+		return r.mb, r.err
+	default:
+		return nil, nil
+	}
+}
+
 // Writer extends io.Writer with MultiBuffer.
 type Writer interface {
 	// WriteMultiBuffer writes a MultiBuffer into underlying writer.