Chris Lu
5 years ago
2 changed files with 242 additions and 0 deletions
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package bounded_tree |
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import ( |
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"fmt" |
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"github.com/chrislusf/seaweedfs/weed/glog" |
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"github.com/chrislusf/seaweedfs/weed/util" |
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) |
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type Node struct { |
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Parent *Node |
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Name string |
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Children map[string]*Node |
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} |
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type BoundedTree struct { |
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root *Node |
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} |
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func NewBoundedTree() *BoundedTree { |
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return &BoundedTree{ |
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root: &Node{ |
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Name: "/", |
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}, |
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} |
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} |
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type VisitNodeFunc func(path util.FullPath) (childDirectories []string, err error) |
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// If the path is not visited, call the visitFn for each level of directory
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// No action if the directory has been visited before or does not exist.
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// A leaf node, which has no children, represents a directory not visited.
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// A non-leaf node or a non-existing node represents a directory already visited, or does not need to visit.
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func (t *BoundedTree) EnsureVisited(p util.FullPath, visitFn VisitNodeFunc) { |
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println() |
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println("EnsureVisited", p) |
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if t.root == nil { |
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return |
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} |
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components := p.Split() |
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fmt.Printf("components %v %d\n", components, len(components)) |
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if canDelete := t.ensureVisited(t.root, util.FullPath("/"), components, 0, visitFn); canDelete { |
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t.root = nil |
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} |
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} |
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func (t *BoundedTree) ensureVisited(n *Node, currentPath util.FullPath, components []string, i int, visitFn VisitNodeFunc) (canDeleteNode bool) { |
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println("ensureVisited", currentPath, i) |
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if n == nil { |
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fmt.Printf("%s null\n", currentPath) |
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return |
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} |
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if n.isVisited() { |
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fmt.Printf("%s visited %v\n", currentPath, n.Name) |
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} else { |
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fmt.Printf("ensure %v\n", currentPath) |
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children, err := visitFn(currentPath) |
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if err != nil { |
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glog.V(0).Infof("failed to visit %s: %v", currentPath, err) |
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return |
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} |
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if len(children) == 0 { |
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fmt.Printf(" canDelete %v without children\n", currentPath) |
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return true |
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} |
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n.Children = make(map[string]*Node) |
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for _, child := range children { |
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fmt.Printf(" add child %v %v\n", currentPath, child) |
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n.Children[child] = &Node{ |
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Name: child, |
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} |
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} |
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} |
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if i >= len(components) { |
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return |
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} |
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fmt.Printf(" check child %v %v\n", currentPath, components[i]) |
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toVisitNode, found := n.Children[components[i]] |
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if !found { |
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fmt.Printf(" did not find child %v %v\n", currentPath, components[i]) |
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return |
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} |
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fmt.Printf(" ensureVisited %v %v\n", currentPath, toVisitNode.Name) |
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if canDelete := t.ensureVisited(toVisitNode, currentPath.Child(components[i]), components, i+1, visitFn); canDelete { |
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fmt.Printf(" delete %v %v\n", currentPath, components[i]) |
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delete(n.Children, components[i]) |
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if len(n.Children) == 0 { |
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fmt.Printf(" canDelete %v\n", currentPath) |
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return true |
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} |
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} |
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return false |
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} |
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func (n *Node) isVisited() bool { |
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if n == nil { |
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return true |
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} |
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if len(n.Children) > 0 { |
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return true |
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} |
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return false |
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} |
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func (n *Node) getChild(childName string) *Node { |
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if n == nil { |
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return nil |
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} |
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if len(n.Children) > 0 { |
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return n.Children[childName] |
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} |
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return nil |
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} |
@ -0,0 +1,113 @@ |
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package bounded_tree |
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import ( |
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"fmt" |
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"testing" |
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"github.com/chrislusf/seaweedfs/weed/util" |
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) |
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var ( |
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visitFn = func(path util.FullPath) (childDirectories []string, err error) { |
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fmt.Printf(" visit %v ...\n", path) |
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switch path { |
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case "/": |
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return []string{"a", "g", "h"}, nil |
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case "/a": |
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return []string{"b", "f"}, nil |
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case "/a/b": |
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return []string{"c", "e"}, nil |
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case "/a/b/c": |
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return []string{"d"}, nil |
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case "/a/b/c/d": |
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return []string{"i", "j"}, nil |
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case "/a/b/c/d/i": |
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return []string{}, nil |
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case "/a/b/c/d/j": |
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return []string{}, nil |
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case "/a/b/e": |
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return []string{}, nil |
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case "/a/f": |
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return []string{}, nil |
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} |
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return nil, nil |
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} |
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printMap = func(m map[string]*Node) { |
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for k := range m { |
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println(" >", k) |
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} |
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} |
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) |
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func TestBoundedTree(t *testing.T) { |
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// a/b/c/d/i
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// a/b/c/d/j
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// a/b/c/d
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// a/b/e
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// a/f
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// g
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// h
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tree := NewBoundedTree() |
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tree.EnsureVisited(util.FullPath("/a/b/c"), visitFn) |
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printMap(tree.root.Children) |
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a := tree.root.getChild("a") |
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b := a.getChild("b") |
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if !b.isVisited() { |
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t.Errorf("expect visited /a/b") |
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} |
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c := b.getChild("c") |
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if !c.isVisited() { |
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t.Errorf("expect visited /a/b/c") |
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} |
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d := c.getChild("d") |
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if d.isVisited() { |
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t.Errorf("expect unvisited /a/b/c/d") |
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} |
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tree.EnsureVisited(util.FullPath("/a/b/c/d"), visitFn) |
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tree.EnsureVisited(util.FullPath("/a/b/c/d/i"), visitFn) |
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tree.EnsureVisited(util.FullPath("/a/b/c/d/j"), visitFn) |
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tree.EnsureVisited(util.FullPath("/a/b/e"), visitFn) |
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tree.EnsureVisited(util.FullPath("/a/f"), visitFn) |
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printMap(tree.root.Children) |
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} |
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func TestEmptyBoundedTree(t *testing.T) { |
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// g
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// h
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tree := NewBoundedTree() |
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visitFn := func(path util.FullPath) (childDirectories []string, err error) { |
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fmt.Printf(" visit %v ...\n", path) |
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switch path { |
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case "/": |
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return []string{"g", "h"}, nil |
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} |
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t.Fatalf("expected visit %s", path) |
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return nil, nil |
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} |
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tree.EnsureVisited(util.FullPath("/a/b"), visitFn) |
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tree.EnsureVisited(util.FullPath("/a/b"), visitFn) |
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printMap(tree.root.Children) |
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} |
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