// uses slash separated paths.
func WalkDir(root string, fn fs.WalkDirFunc) error {
	info, err := os.Lstat(root)
	if err != nil {
		err = fn(root, nil, err)
	} else {
		err = walkDir(root, fs.FileInfoToDirEntry(info), fn)
	}
	if err == SkipDir || err == SkipAll {
		return nil
	}
	return err
}

// Walk walks the file tree rooted at root, calling fn for each file or

func (conf *dnsConfig) nameList(name string) []string {
	// Check name length (see isDomainName).
	l := len(name)
	rooted := l > 0 && name[l-1] == '.'
	if l > 254 || l == 254 && !rooted {
		return nil
	}

	// If name is rooted (trailing dot), try only that name.
	if rooted {
		if avoidDNS(name) {
			return nil
		}
		return []string{name}
	}

}

// A Generator represents the state of a single Go source file
// being scanned for generator commands.
type Generator struct {
	r        io.Reader
	path     string // full rooted path name.
	dir      string // full rooted directory of file.
	file     string // base name of file.
	pkg      string
	commands map[string][]string
	lineNum  int // current line number.
	env      []string
}

	Short:     "package lists and patterns",
	Long: `
Many commands apply to a set of packages:

	go <action> [packages]

Usually, [packages] is a list of import paths.

An import path that is a rooted path or that begins with
a . or .. element is interpreted as a file system path and
denotes the package in that directory.

Otherwise, the import path P denotes the package found in

// but may produce false positives on non-trivial paths.
func pathNeedsClean(path []byte) bool {
	if len(path) == 0 {
		return true
	}

	rooted := path[0] == '/'
	n := len(path)

	r, w := 0, 0
	if rooted {
		r, w = 1, 1
	}

	for r < n {
		switch {
		case path[r] > 127:
			// Non ascii.
			return true
		case path[r] == '/':
			// multiple / elements

				"or add it to the kubeletConfigurationNonPathFieldPaths set, as appropriate:\n%s",
				strings.Join(sets.List(unexpected), "\n"))
		}
	}
}

// allPrimitiveFieldPaths returns the set of field paths in type `tp`, rooted at `path`.
// It recursively descends into the definition of type `tp` accumulating paths to primitive leaf fields or paths in `skipRecurseList`.

	// (see loop in semacquire).
	if root.nwait.Load() == 0 {
		return
	}

	// Harder case: search for a waiter and wake it.
	lockWithRank(&root.lock, lockRankRoot)
	if root.nwait.Load() == 0 {
		// The count is already consumed by another goroutine,
		// so no need to wake up another goroutine.
		unlock(&root.lock)
		return
	}
	s, t0, tailtime := root.dequeue(addr)
	if s != nil {
		root.nwait.Add(-1)

		if node, ok := path[i].(*ast.IfStmt); ok && node.Else == stmt {
			stmt = node
			continue
		}
		break
	}
	return stmt.(ast.Stmt)
}

// WalkASTWithParent walks the AST rooted at n. The semantics are
// similar to ast.Inspect except it does not call f(nil).
func WalkASTWithParent(n ast.Node, f func(n ast.Node, parent ast.Node) bool) {
	var ancestors []ast.Node

	}
}

// xremove removes the file p.
func xremove(p string) {
	if vflag > 2 {
		errprintf("rm %s\n", p)
	}
	os.Remove(p)
}

// xremoveall removes the file or directory tree rooted at p.
func xremoveall(p string) {
	if vflag > 2 {
		errprintf("rm -r %s\n", p)
	}
	os.RemoveAll(p)
}

// xreaddir replaces dst with a list of the names of the files and subdirectories in dir.

// The files provided by fsys must implement [io.Seeker].
func FS(fsys fs.FS) FileSystem {
	return ioFS{fsys}
}

// FileServer returns a handler that serves HTTP requests
// with the contents of the file system rooted at root.
//
// As a special case, the returned file server redirects any request
// ending in "/index.html" to the same path, without the final
// "index.html".
//