如何用Golang组合模式管理复杂结构 演示文件系统目录树的实现

type Node interface {
    GetName() string
    GetSize() int
    String() string
}

type File struct {
    name string
    size int
}

func (f *File) GetName() string {
    return f.name
}

func (f *File) GetSize() int {
    return f.size
}

func (f *File) String() string {
    return f.name + " (" + strconv.Itoa(f.size) + " KB)"
}

type Directory struct {
    name     string
    children []Node
}

func (d *Directory) GetName() string {
    return d.name
}

func (d *Directory) GetSize() int {
    total := 0
    for _, child := range d.children {
        total += child.GetSize()
    }
    return total
}

func (d *Directory) String() string {
    var res strings.Builder
    res.WriteString(d.name + " (" + strconv.Itoa(d.GetSize()) + " KB)\n")
    for _, child := range d.children {
        res.WriteString(" - " + child.String() + "\n")
    }
    return res.String()
}

func (d *Directory) Add(child Node) {
    d.children = append(d.children, child)
}

root := &Directory{name: "root"}
home := &Directory{name: "home"}
user := &Directory{name: "alice"}

file1 := &File{name: "notes.txt", size: 20}
file2 := &File{name: "photo.jpg", size: 500}

user.Add(file1)
user.Add(file2)
home.Add(user)
root.Add(home)

fmt.Println(root)

root (520 KB)
 - home (520 KB)
   - alice (520 KB)
     - notes.txt (20 KB)
     - photo.jpg (500 KB)