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rclone/lib/file/mkdir_windows.go
albertony fbc7f2e61b lib/file: improve error message when attempting to create dir on nonexistent drive on windows
This replaces built-in os.MkdirAll with a patched version that stops the recursion
when reaching the volume part of the path. The original version would continue recursion,
and for extended length paths end up with \\? as the top-level directory, and the error
message would then be something like:
mkdir \\?: The filename, directory name, or volume label syntax is incorrect.
2021-10-01 23:18:39 +02:00

78 lines
2.0 KiB
Go

//go:build windows
// +build windows
package file
import (
"os"
"path/filepath"
"syscall"
)
// MkdirAll creates a directory named path, along with any necessary parents.
//
// Improves os.MkdirAll by avoiding trying to create a folder \\? when the
// volume of a given extended length path does not exist.
//
// Based on source code from golang's os.MkdirAll
// (https://github.com/golang/go/blob/master/src/os/path.go)
func MkdirAll(path string, perm os.FileMode) error {
// Fast path: if we can tell whether path is a directory or file, stop with success or error.
dir, err := os.Stat(path)
if err == nil {
if dir.IsDir() {
return nil
}
return &os.PathError{
Op: "mkdir",
Path: path,
Err: syscall.ENOTDIR,
}
}
// Slow path: make sure parent exists and then call Mkdir for path.
i := len(path)
for i > 0 && os.IsPathSeparator(path[i-1]) { // Skip trailing path separator.
i--
}
if i > 0 {
path = path[:i]
if path == filepath.VolumeName(path) {
// Make reference to a drive's root directory include the trailing slash.
// In extended-length form without trailing slash ("\\?\C:"), os.Stat
// and os.Mkdir both fails. With trailing slash ("\\?\C:\") works,
// and regular paths with or without it ("C:" and "C:\") both works.
path = path + string(os.PathSeparator)
} else {
// See if there is a parent to be created first.
// Not when path refer to a drive's root directory, because we don't
// want to return noninformative error trying to create \\?.
j := i
for j > 0 && !os.IsPathSeparator(path[j-1]) { // Scan backward over element.
j--
}
if j > 1 {
// Create parent.
err = MkdirAll(path[:j-1], perm)
if err != nil {
return err
}
}
}
}
// Parent now exists; invoke Mkdir and use its result.
err = os.Mkdir(path, perm)
if err != nil {
// Handle arguments like "foo/." by
// double-checking that directory doesn't exist.
dir, err1 := os.Lstat(path)
if err1 == nil && dir.IsDir() {
return nil
}
return err
}
return nil
}