Replace local *FileInformationByHandleEx with x/sys/windows

We also get pre-defined constants instead of carrying our own copies.

However, this changes the public API winio.FileBasicInfo from using
syscall.Filetime to using windows.Filetime, as visible in
backuptar/tar.go.

Signed-off-by: Paul "TBBle" Hampson <Paul.Hampson@Pobox.com>

backuptar/tar.go

@@ -16,6 +16,7 @@ import (
 	"time"
 
 	"github.com/Microsoft/go-winio"
+	"golang.org/x/sys/windows"
 )
 
 const (
@@ -297,11 +298,11 @@ func FileInfoFromHeader(hdr *tar.Header) (name string, size int64, fileInfo *win
 		size = hdr.Size
 	}
 	fileInfo = &winio.FileBasicInfo{
-		LastAccessTime: syscall.NsecToFiletime(hdr.AccessTime.UnixNano()),
-		LastWriteTime:  syscall.NsecToFiletime(hdr.ModTime.UnixNano()),
-		ChangeTime:     syscall.NsecToFiletime(hdr.ChangeTime.UnixNano()),
+		LastAccessTime: windows.NsecToFiletime(hdr.AccessTime.UnixNano()),
+		LastWriteTime:  windows.NsecToFiletime(hdr.ModTime.UnixNano()),
+		ChangeTime:     windows.NsecToFiletime(hdr.ChangeTime.UnixNano()),
 		// Default to ModTime, we'll pull hdrCreationTime below if present
-		CreationTime: syscall.NsecToFiletime(hdr.ModTime.UnixNano()),
+		CreationTime: windows.NsecToFiletime(hdr.ModTime.UnixNano()),
 	}
 	if attrStr, ok := hdr.PAXRecords[hdrFileAttributes]; ok {
 		attr, err := strconv.ParseUint(attrStr, 10, 32)
@@ -319,7 +320,7 @@ func FileInfoFromHeader(hdr *tar.Header) (name string, size int64, fileInfo *win
 		if err != nil {
 			return "", 0, nil, err
 		}
-		fileInfo.CreationTime = syscall.NsecToFiletime(creationTime.UnixNano())
+		fileInfo.CreationTime = windows.NsecToFiletime(creationTime.UnixNano())
 	}
 	return
 }

fileinfo.go

@@ -5,29 +5,22 @@ package winio
 import (
 	"os"
 	"runtime"
-	"syscall"
 	"unsafe"
-)
-
-//sys getFileInformationByHandleEx(h syscall.Handle, class uint32, buffer *byte, size uint32) (err error) = GetFileInformationByHandleEx
-//sys setFileInformationByHandle(h syscall.Handle, class uint32, buffer *byte, size uint32) (err error) = SetFileInformationByHandle
 
-const (
-	fileBasicInfo = 0
-	fileIDInfo    = 0x12
+	"golang.org/x/sys/windows"
 )
 
 // FileBasicInfo contains file access time and file attributes information.
 type FileBasicInfo struct {
-	CreationTime, LastAccessTime, LastWriteTime, ChangeTime syscall.Filetime
+	CreationTime, LastAccessTime, LastWriteTime, ChangeTime windows.Filetime
 	FileAttributes                                          uint32
 	pad                                                     uint32 // padding
 }
 
 // GetFileBasicInfo retrieves times and attributes for a file.
 func GetFileBasicInfo(f *os.File) (*FileBasicInfo, error) {
 	bi := &FileBasicInfo{}
-	if err := getFileInformationByHandleEx(syscall.Handle(f.Fd()), fileBasicInfo, (*byte)(unsafe.Pointer(bi)), uint32(unsafe.Sizeof(*bi))); err != nil {
+	if err := windows.GetFileInformationByHandleEx(windows.Handle(f.Fd()), windows.FileBasicInfo, (*byte)(unsafe.Pointer(bi)), uint32(unsafe.Sizeof(*bi))); err != nil {
 		return nil, &os.PathError{Op: "GetFileInformationByHandleEx", Path: f.Name(), Err: err}
 	}
 	runtime.KeepAlive(f)
@@ -36,7 +29,7 @@ func GetFileBasicInfo(f *os.File) (*FileBasicInfo, error) {
 
 // SetFileBasicInfo sets times and attributes for a file.
 func SetFileBasicInfo(f *os.File, bi *FileBasicInfo) error {
-	if err := setFileInformationByHandle(syscall.Handle(f.Fd()), fileBasicInfo, (*byte)(unsafe.Pointer(bi)), uint32(unsafe.Sizeof(*bi))); err != nil {
+	if err := windows.SetFileInformationByHandle(windows.Handle(f.Fd()), windows.FileBasicInfo, (*byte)(unsafe.Pointer(bi)), uint32(unsafe.Sizeof(*bi))); err != nil {
 		return &os.PathError{Op: "SetFileInformationByHandle", Path: f.Name(), Err: err}
 	}
 	runtime.KeepAlive(f)
@@ -53,7 +46,7 @@ type FileIDInfo struct {
 // GetFileID retrieves the unique (volume, file ID) pair for a file.
 func GetFileID(f *os.File) (*FileIDInfo, error) {
 	fileID := &FileIDInfo{}
-	if err := getFileInformationByHandleEx(syscall.Handle(f.Fd()), fileIDInfo, (*byte)(unsafe.Pointer(fileID)), uint32(unsafe.Sizeof(*fileID))); err != nil {
+	if err := windows.GetFileInformationByHandleEx(windows.Handle(f.Fd()), windows.FileIdInfo, (*byte)(unsafe.Pointer(fileID)), uint32(unsafe.Sizeof(*fileID))); err != nil {
 		return nil, &os.PathError{Op: "GetFileInformationByHandleEx", Path: f.Name(), Err: err}
 	}
 	runtime.KeepAlive(f)