code review 177590043: net: FileListener on windows

src/net/file_windows.go

Index: src/net/file_windows.go 
=================================================================== 
--- a/src/net/file_windows.go 
+++ b/src/net/file_windows.go 
@@ -9,13 +9,106 @@ 
	"syscall" 
 ) 
 
+func dupCloseOnExec(fd int) (syscall.Handle, error) { 
+	var h syscall.Handle 
+	p, _ := syscall.GetCurrentProcess() 
+	err := syscall.DuplicateHandle(p, syscall.Handle(fd), p, &h, 0, false, syscall.DUPLICATE_SAME_ACCESS) 
+	if err != nil { 
+	return 0, err 
+	} 
+	return h, nil 
+} 
+ 
+func newFileFD(f *os.File) (*netFD, error) { 
+	fd, err := dupCloseOnExec(int(f.Fd())) 
+	if err != nil { 
+	return nil, os.NewSyscallError("dup", err) 
+	} 
+ 
+	if err = syscall.SetNonblock(fd, true); err != nil { 
+	closesocket(fd) 
+	return nil, err 
+	} 
+ 
+	sotype, err := syscall.GetsockoptInt(fd, syscall.SOL_SOCKET, syscall.SO_TYPE) 
+	if err != nil { 
+	closesocket(fd) 
+	return nil, os.NewSyscallError("getsockopt", err) 
+	} 
+	lsa, err := syscall.Getsockname(fd) 
+	if err != nil { 
+	return nil, os.NewSyscallError("getsockname", err) 
+	} 
+ 
+	family := syscall.AF_UNSPEC 
+	toAddr := sockaddrToTCP 
+	switch lsa.(type) { 
+	default: 
+	closesocket(fd) 
+	return nil, syscall.EINVAL 
+	case *syscall.SockaddrInet4: 
+	family = syscall.AF_INET 
+	if sotype == syscall.SOCK_DGRAM { 
+	toAddr = sockaddrToUDP 
+	} else if sotype == syscall.SOCK_RAW { 
+	toAddr = sockaddrToIP 
+	} 
+	case *syscall.SockaddrInet6: 
+	family = syscall.AF_INET6 
+	if sotype == syscall.SOCK_DGRAM { 
+	toAddr = sockaddrToUDP 
+	} else if sotype == syscall.SOCK_RAW { 
+	toAddr = sockaddrToIP 
+	} 
+	case *syscall.SockaddrUnix: 
+	return nil, os.NewSyscallError("UnixListener", syscall.EWINDOWS) 
+	} 
+	laddr := toAddr(lsa) 
+	rsa, _ := syscall.Getpeername(fd) 
+	raddr := toAddr(rsa) 
+ 
+	netfd, err := newFD(fd, family, sotype, laddr.Network()) 
+	if err != nil { 
+	closesocket(fd) 
+	return nil, err 
+	} 
+	// fd is not handled yet 
+	if err := netfd.init(); err != nil { 
+	// handle invalid parameter. When passing same handle to 
+	// CreateIoCompletionPort twice, it returns ERROR_INVALID_PARAMETER(87). 
+	// Ignoring this here because when passing handle into this function 
+	// from external process, Or create socket manually and pass to here, 
+	// this init() should work gracefully. 
+	if errno, ok := err.(syscall.Errno); ok && int(errno) != -87 { 
+	netfd.Close() 
+	return nil, err 
+	} 
+	} 
+	netfd.setAddr(laddr, raddr) 
+	return netfd, nil 
+} 
+ 
 // FileConn returns a copy of the network connection corresponding to 
 // the open file f. It is the caller's responsibility to close f when 
 // finished. Closing c does not affect f, and closing f does not 
 // affect c. 
 func FileConn(f *os.File) (c Conn, err error) { 
-	// TODO: Implement this 
-	return nil, os.NewSyscallError("FileConn", syscall.EWINDOWS) 
+	fd, err := newFileFD(f) 
+	if err != nil { 
+	return nil, err 
+	} 
+	switch fd.laddr.(type) { 
+	case *TCPAddr: 
+	return newTCPConn(fd), nil 
+	case *UDPAddr: 
+	return newUDPConn(fd), nil 
+	case *IPAddr: 
+	return newIPConn(fd), nil 
+	case *UnixAddr: 
+	return nil, os.NewSyscallError("FileConn", syscall.EWINDOWS) 
+	} 
+	fd.Close() 
+	return nil, syscall.EINVAL 
 } 
 
 // FileListener returns a copy of the network listener corresponding 
@@ -23,8 +116,18 @@ 
 // when finished. Closing l does not affect f, and closing f does not 
 // affect l. 
 func FileListener(f *os.File) (l Listener, err error) { 
-	// TODO: Implement this 
-	return nil, os.NewSyscallError("FileListener", syscall.EWINDOWS) 
+	fd, err := newFileFD(f) 
+	if err != nil { 
+	return nil, err 
+	} 
+	switch fd.laddr.(type) { 
+	case *TCPAddr: 
+	return &TCPListener{fd}, nil 
+	case *UnixAddr: 
+	return nil, os.NewSyscallError("UnixListener", syscall.EWINDOWS) 
+	} 
+	fd.Close() 
+	return nil, syscall.EINVAL 
 } 
 
 // FilePacketConn returns a copy of the packet network connection