Use short path for LIMA_HOME on windows

Other commands such as qemu-system-x86_64.exe don't work with
C:\Users\AndersBjörklund, they need to use C:\Users\ANDERS~1

In theory they could have supported using UNC paths such as
\\?\C:\Users\AndersBjörklund, but in practice they do not...

Signed-off-by: Anders F Björklund <[email protected]>

Author: afbjorklund

pkg/store/dirnames/dirnames.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"runtime"
 
 	"github.com/lima-vm/lima/pkg/store/filenames"
 )
@@ -24,11 +25,22 @@ func LimaDir() (string, error) {
 		if err != nil {
 			return "", err
 		}
+		// on windows, DOS paths are needed by some tools like QEMU
+		if runtime.GOOS == "windows" {
+			homeDir, err = ShortName(homeDir)
+			if err != nil {
+				return "", err
+			}
+		}
 		dir = filepath.Join(homeDir, DotLima)
 	}
 	if _, err := os.Stat(dir); errors.Is(err, os.ErrNotExist) {
 		return dir, nil
 	}
+	// on windows, EvalSymlinks translates short paths back to long again
+	if runtime.GOOS == "windows" {
+		return dir, nil
+	}
 	realdir, err := filepath.EvalSymlinks(dir)
 	if err != nil {
 		return "", fmt.Errorf("cannot evaluate symlinks in %q: %w", dir, err)

pkg/store/dirnames/shortname_others.go

@@ -0,0 +1,8 @@
+//go:build !windows
+// +build !windows
+
+package dirnames
+
+func ShortName(path string) (string, error) {
+	return path, nil
+}

pkg/store/dirnames/shortname_test.go

@@ -0,0 +1,34 @@
+package dirnames
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"gotest.tools/v3/assert"
+)
+
+// Note: can't use t.TempDir(), because it is _always_ long... <sigh>
+//       instead use os.TempDir(), something like `C:\users\anders\Temp`
+
+func TestShortNameShort(t *testing.T) {
+	d := os.TempDir()
+	l := filepath.Join(d, "foo")
+	err := os.Mkdir(l, 0755)
+	assert.NilError(t, err)
+	s, err := ShortName(l)
+	t.Logf("%s => %s", l, s)
+	assert.NilError(t, err)
+	os.RemoveAll(l)
+}
+
+func TestShortNameLong(t *testing.T) {
+	d := os.TempDir()
+	l := filepath.Join(d, "baaaaaaaaaar")
+	err := os.Mkdir(l, 0755)
+	assert.NilError(t, err)
+	s, err := ShortName(l)
+	t.Logf("%s => %s", l, s)
+	assert.NilError(t, err)
+	os.RemoveAll(l)
+}

pkg/store/dirnames/shortname_windows.go

@@ -0,0 +1,22 @@
+package dirnames
+
+import (
+	"syscall"
+)
+
+func ShortName(path string) (string, error) {
+	p := syscall.StringToUTF16(path)
+	b := p // GetShortPathName says we can reuse buffer
+	n, err := syscall.GetShortPathName(&p[0], &b[0], uint32(len(b)))
+	if err != nil {
+		return "", err
+	}
+	if n > uint32(len(b)) {
+		b = make([]uint16, n)
+		n, err = syscall.GetShortPathName(&p[0], &b[0], uint32(len(b)))
+		if err != nil {
+			return "", err
+		}
+	}
+	return syscall.UTF16ToString(b), nil
+}