vendor: github.com/moby/buildkit v0.21.0-rc1

Signed-off-by: Jonathan A. Sternberg <jonathan.sternberg@docker.com>

vendor/github.com/moby/buildkit/util/system/path_windows.go

@@ -0,0 +1,29 @@
+package system
+
+import (
+	"path/filepath"
+	"strings"
+)
+
+// DefaultSystemVolumeName is the default system volume label on Windows
+const DefaultSystemVolumeName = "C:"
+
+// IsAbsolutePath prepends the default system volume label
+// to the path that is presumed absolute, and then calls filepath.IsAbs
+func IsAbsolutePath(path string) bool {
+	path = filepath.Clean(path)
+	if strings.HasPrefix(path, "\\") {
+		path = DefaultSystemVolumeName + path
+	}
+	return filepath.IsAbs(path)
+}
+
+// GetAbsolutePath returns an absolute path rooted
+// to C:\\ on Windows.
+func GetAbsolutePath(path string) string {
+	path = filepath.Clean(path)
+	if len(path) >= 2 && strings.EqualFold(path[:2], DefaultSystemVolumeName) {
+		return path
+	}
+	return DefaultSystemVolumeName + path
+}