golang/dep

// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// +build windows

package fs

import (
    "os"
    "syscall"

    "github.com/pkg/errors"
)

// renameFallback attempts to determine the appropriate fallback to failed rename
// operation depending on the resulting error.
func renameFallback(err error, src, dst string) error {
    // Rename may fail if src and dst are on different devices; fall back to
    // copy if we detect that case. syscall.EXDEV is the common name for the
    // cross device link error which has varying output text across different
    // operating systems.
    terr, ok := err.(*os.LinkError)
    if !ok {
        return err
    }

    if terr.Err != syscall.EXDEV {
        // In windows it can drop down to an operating system call that
        // returns an operating system error with a different number and
        // message. Checking for that as a fall back.
        noerr, ok := terr.Err.(syscall.Errno)

        // 0x11 (ERROR_NOT_SAME_DEVICE) is the windows error.
        // See https://msdn.microsoft.com/en-us/library/cc231199.aspx
        if ok && noerr != 0x11 {
            return errors.Wrapf(terr, "link error: cannot rename %s to %s", src, dst)
        }
    }

    return renameByCopy(src, dst)
}