feat: add support for mega.nz (close 1553)

pkg/chanio/chanio.go

@@ -0,0 +1,62 @@
+package chanio
+
+import (
+	"io"
+	"sync/atomic"
+)
+
+type ChanIO struct {
+	cl  atomic.Bool
+	c   chan []byte
+	buf []byte
+}
+
+func New() *ChanIO {
+	return &ChanIO{
+		cl:  atomic.Bool{},
+		c:   make(chan []byte),
+		buf: make([]byte, 0),
+	}
+}
+
+func (c *ChanIO) Read(p []byte) (int, error) {
+	if c.cl.Load() {
+		if len(c.buf) == 0 {
+			return 0, io.EOF
+		}
+		n := copy(p, c.buf)
+		if len(c.buf) > n {
+			c.buf = c.buf[n:]
+		} else {
+			c.buf = make([]byte, 0)
+		}
+		return n, nil
+	}
+	for len(c.buf) < len(p) && !c.cl.Load() {
+		c.buf = append(c.buf, <-c.c...)
+	}
+	n := copy(p, c.buf)
+	if len(c.buf) > n {
+		c.buf = c.buf[n:]
+	} else {
+		c.buf = make([]byte, 0)
+	}
+	return n, nil
+}
+
+func (c *ChanIO) Write(p []byte) (int, error) {
+	if c.cl.Load() {
+		return 0, io.ErrClosedPipe
+	}
+	c.c <- p
+	return len(p), nil
+}
+
+func (c *ChanIO) Close() error {
+	if c.cl.Load() {
+		return io.ErrClosedPipe
+	}
+	c.cl.Store(true)
+	close(c.c)
+	return nil
+}