PipeListenerDialer.Close should be called once

PipeListenerDialer.Close will return unix.EINVAL if it is called more
than once. This is to emulate the behavior of other standard listeners.

Also:

  * PipeListenerDialer.Accept will return (nil, unix.EINVAL) if the
    listener is closed. This roughly matches with behavior described in
    accept(2).

  * PipeListenerDialer.Dial will also return (nil, unix.EINVAL) if the
    address passed does not match the one passed to New. It will also
    return (nil, unix.ECONNREFUSED) if the listener is closed. This
    roughly matches the behavior described in connect(2) and unix(7).

  * The custom errors ErrBadAddress and ErrClosed are removed.

1 files changed, 10 insertions, 9 deletions

diff --git a/pipeln.go b/pipeln.go
index c836f28..29c6523 100644
--- a/pipeln.go
+++ b/pipeln.go
@@ -4,13 +4,9 @@ package pipeln
 
 import (
 	"context"
-	"errors"
 	"net"
-)
 
-var (
-	ErrBadAddress = errors.New("bad address")
-	ErrClosed     = errors.New("closed listener")
+	"golang.org/x/sys/unix"
 )
 
 type addr struct {
@@ -34,6 +30,7 @@ type PipeListenerDialer struct {
 	addr  string
 	conns chan net.Conn
 	done  chan struct{}
+	ok    bool
 }
 
 var _ net.Listener = &PipeListenerDialer{}
@@ -43,7 +40,7 @@ func (ln *PipeListenerDialer) Accept() (net.Conn, error) {
 	case conn := <-ln.conns:
 		return conn, nil
 	case <-ln.done:
-		return nil, ErrClosed
+		return nil, unix.EINVAL
 	}
 }
 
@@ -52,20 +49,24 @@ func (ln *PipeListenerDialer) Addr() net.Addr {
 }
 
 func (ln *PipeListenerDialer) Close() error {
+	if !ln.ok {
+		return unix.EINVAL
+	}
 	close(ln.done)
+	ln.ok = false
 	return nil
 }
 
 func (ln *PipeListenerDialer) Dial(_, addr string) (net.Conn, error) {
 	if addr != ln.addr {
-		return nil, ErrBadAddress
+		return nil, unix.EINVAL
 	}
 	s, c := net.Pipe()
 	select {
 	case ln.conns <- s:
 		return c, nil
 	case <-ln.done:
-		return nil, ErrClosed
+		return nil, unix.ECONNREFUSED
 	}
 }
 
@@ -78,5 +79,5 @@ func (ln *PipeListenerDialer) DialContextAddr(_ context.Context, addr string) (n
 }
 
 func New(addr string) *PipeListenerDialer {
-	return &PipeListenerDialer{addr, make(chan net.Conn), make(chan struct{})}
+	return &PipeListenerDialer{addr, make(chan net.Conn), make(chan struct{}), true}
 }