implementing inode equivalent on windows

Signed-off-by: Juan Bustamante <[email protected]>

pkg/archive/archive.go

@@ -220,7 +220,7 @@ func WriteDirToTar(tw TarWriter, srcDir, basePath string, uid, gid int, mode int
 
 		header.Name = getHeaderNameFromBaseAndRelPath(basePath, relPath)
 		if hasHardlinks(fi, file) {
-			inode, err := getInodeFromStat(fi.Sys())
+			inode, err := getInodeFromStat(fi.Sys(), file)
 			if err != nil {
 				return err
 			}

pkg/archive/archive_unix.go

@@ -11,7 +11,7 @@ func hasHardlinks(fi os.FileInfo, path string) bool {
 	return fi.Sys().(*syscall.Stat_t).Nlink > 1
 }
 
-func getInodeFromStat(stat interface{}) (inode uint64, err error) {
+func getInodeFromStat(stat interface{}, path string) (inode uint64, err error) {
 	s, ok := stat.(*syscall.Stat_t)
 	if ok {
 		inode = s.Ino

pkg/archive/archive_windows.go

@@ -14,40 +14,50 @@ func hasHardlinks(fi os.FileInfo, path string) bool {
 	case *syscall.ByHandleFileInformation:
 		numberOfLinks = v.NumberOfLinks
 	default:
-		// We need to open the file and create an instance of a ByHandleFileInformation
-		fPath, err := syscall.UTF16PtrFromString(path)
-		if err != nil {
-			return false
-		}
-
-		handle, err := syscall.CreateFile(
-			fPath,
-			windows.FILE_READ_ATTRIBUTES,
-			syscall.FILE_SHARE_READ|syscall.FILE_SHARE_WRITE|syscall.FILE_SHARE_DELETE,
-			nil,
-			syscall.OPEN_EXISTING,
-			syscall.FILE_FLAG_BACKUP_SEMANTICS,
-			0)
-		if err != nil {
-			return false
+		if info, err := open(path); err == nil {
+			numberOfLinks = info.NumberOfLinks
 		}
-		defer syscall.CloseHandle(handle)
-
-		// Get the number of links
-		var info syscall.ByHandleFileInformation
-		err = syscall.GetFileInformationByHandle(handle, &info)
-		if err != nil {
-			return false
-		}
-		numberOfLinks = info.NumberOfLinks
 	}
 	return numberOfLinks > 1
 }
 
-func getInodeFromStat(stat interface{}) (inode uint64, err error) {
+func getInodeFromStat(stat interface{}, path string) (inode uint64, err error) {
 	s, ok := stat.(*syscall.ByHandleFileInformation)
 	if ok {
-		inode = uint64(s.VolumeSerialNumber)
+		inode = (uint64(s.FileIndexHigh) << 32) | uint64(s.FileIndexLow)
+	} else {
+		s, err = open(path)
+		if err != nil {
+			inode = (uint64(s.FileIndexHigh) << 32) | uint64(s.FileIndexLow)
+		}
 	}
 	return
 }
+
+func open(path string) (*syscall.ByHandleFileInformation, error) {
+	// We need to open the file and create an instance of a ByHandleFileInformation
+	fPath, err := syscall.UTF16PtrFromString(path)
+	if err != nil {
+		return nil, err
+	}
+
+	handle, err := syscall.CreateFile(
+		fPath,
+		windows.FILE_READ_ATTRIBUTES,
+		syscall.FILE_SHARE_READ|syscall.FILE_SHARE_WRITE|syscall.FILE_SHARE_DELETE,
+		nil,
+		syscall.OPEN_EXISTING,
+		syscall.FILE_FLAG_BACKUP_SEMANTICS,
+		0)
+	if err != nil {
+		return nil, err
+	}
+	defer syscall.CloseHandle(handle)
+
+	var info syscall.ByHandleFileInformation
+	err = syscall.GetFileInformationByHandle(handle, &info)
+	if err != nil {
+		return nil, err
+	}
+	return &info, nil
+}