Add file and pipe Windows wrappers

This includes Reader, Writer, and Closer interfaces on top of
Windows file handles in a way that does not block the system thread
while the IO is outstanding.

This also includes net.Listener and net.Conn for named pipes.

pipe_test.go

@@ -0,0 +1,148 @@
+package winio
+
+import (
+	"bufio"
+	"net"
+	"os"
+	"syscall"
+	"testing"
+	"time"
+)
+
+var testPipeName = `\\.\pipe\winiotestpipe`
+
+func TestDialUnknownFailsImmediately(t *testing.T) {
+	_, err := DialPipe(testPipeName, nil)
+	if err.(*os.PathError).Err != syscall.ENOENT {
+		t.Fatalf("expected ENOENT got %v", err)
+	}
+}
+
+func TestDialListenerTimesOut(t *testing.T) {
+	l, err := ListenPipe(testPipeName, "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer l.Close()
+	var d = time.Duration(10 * time.Millisecond)
+	_, err = DialPipe(testPipeName, &d)
+	if err != syscall.ETIMEDOUT {
+		t.Fatalf("expected ETIMEDOUT, got %v", err)
+	}
+}
+
+func TestDialAccessDeniedWithRestrictedSD(t *testing.T) {
+	l, err := ListenPipe(testPipeName, "D:P(A;;0x1200FF;;;WD)")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer l.Close()
+	_, err = DialPipe(testPipeName, nil)
+	if err.(*os.PathError).Err != syscall.ERROR_ACCESS_DENIED {
+		t.Fatalf("expected EACCES, got %v", err)
+	}
+}
+
+func getConnection() (client net.Conn, server net.Conn, err error) {
+	l, err := ListenPipe(testPipeName, "")
+	if err != nil {
+		return
+	}
+	defer l.Close()
+
+	type response struct {
+		c   net.Conn
+		err error
+	}
+	ch := make(chan response)
+	go func() {
+		c, err := l.Accept()
+		ch <- response{c, err}
+	}()
+
+	c, err := DialPipe(testPipeName, nil)
+	if err != nil {
+		return
+	}
+
+	r := <-ch
+	if err = r.err; err != nil {
+		c.Close()
+		return
+	}
+
+	client = c
+	server = r.c
+	return
+}
+
+func TestReadTimeout(t *testing.T) {
+	c, s, err := getConnection()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+	defer s.Close()
+
+	c.SetReadDeadline(time.Now().Add(10 * time.Millisecond))
+
+	buf := make([]byte, 10)
+	_, err = c.Read(buf)
+	if err != syscall.ETIMEDOUT {
+		t.Fatalf("expected ETIMEDOUT, got %v", err)
+	}
+}
+
+func server(l net.Listener) {
+	c, err := l.Accept()
+	if err != nil {
+		panic(err)
+	}
+	defer c.Close()
+	rw := bufio.NewReadWriter(bufio.NewReader(c), bufio.NewWriter(c))
+	s, err := rw.ReadString('\n')
+	if err != nil {
+		panic(err)
+	}
+	_, err = rw.WriteString("got " + s)
+	if err != nil {
+		panic(err)
+	}
+	err = rw.Flush()
+	if err != nil {
+		panic(err)
+	}
+}
+
+func TestFullListenDialReadWrite(t *testing.T) {
+	l, err := ListenPipe(testPipeName, "")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	go server(l)
+
+	c, err := DialPipe(testPipeName, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rw := bufio.NewReadWriter(bufio.NewReader(c), bufio.NewWriter(c))
+	_, err = rw.WriteString("hello world\n")
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = rw.Flush()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	s, err := rw.ReadString('\n')
+	if err != nil {
+		t.Fatal(err)
+	}
+	ms := "got hello world\n"
+	if s != ms {
+		t.Errorf("expected '%s', got '%s'", ms, s)
+	}
+}