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package bounded_tree
import (
"sync"
"github.com/chrislusf/seaweedfs/weed/glog"
"github.com/chrislusf/seaweedfs/weed/util"
)
type Node struct {
Parent *Node
Name string
Children map[string]*Node
}
type BoundedTree struct {
root *Node
sync.RWMutex
baseDir util.FullPath
}
func NewBoundedTree(baseDir util.FullPath) *BoundedTree {
return &BoundedTree{
root: &Node{
Name: "/",
},
baseDir: baseDir,
}
}
type VisitNodeFunc func(path util.FullPath) (childDirectories []string, err error)
// If the path is not visited, call the visitFn for each level of directory
// No action if the directory has been visited before or does not exist.
// A leaf node, which has no children, represents a directory not visited.
// A non-leaf node or a non-existing node represents a directory already visited, or does not need to visit.
func (t *BoundedTree) EnsureVisited(p util.FullPath, visitFn VisitNodeFunc) (visitErr error) {
t.Lock()
defer t.Unlock()
if t.root == nil {
return
}
if t.baseDir != "/" {
p = p[len(t.baseDir):]
}
components := p.Split()
// fmt.Printf("components %v %d\n", components, len(components))
canDelete, err := t.ensureVisited(t.root, t.baseDir, components, 0, visitFn)
if err != nil {
return err
}
if canDelete {
t.root = nil
}
return nil
}
func (t *BoundedTree) ensureVisited(n *Node, currentPath util.FullPath, components []string, i int, visitFn VisitNodeFunc) (canDeleteNode bool, visitErr error) {
// println("ensureVisited", currentPath, i)
if n == nil {
// fmt.Printf("%s null\n", currentPath)
return
}
if n.isVisited() {
// fmt.Printf("%s visited %v\n", currentPath, n.Name)
} else {
// fmt.Printf("ensure %v\n", currentPath)
filerPath := currentPath
if t.baseDir != "/" {
filerPath = t.baseDir + filerPath
}
children, err := visitFn(filerPath)
if err != nil {
glog.V(0).Infof("failed to visit %s: %v", currentPath, err)
return false, err
}
if len(children) == 0 {
// fmt.Printf(" canDelete %v without children\n", currentPath)
return true, nil
}
n.Children = make(map[string]*Node)
for _, child := range children {
// fmt.Printf(" add child %v %v\n", currentPath, child)
n.Children[child] = &Node{
Name: child,
}
}
}
if i >= len(components) {
return
}
// fmt.Printf(" check child %v %v\n", currentPath, components[i])
toVisitNode, found := n.Children[components[i]]
if !found {
// fmt.Printf(" did not find child %v %v\n", currentPath, components[i])
return
}
// fmt.Printf(" ensureVisited %v %v\n", currentPath, toVisitNode.Name)
canDelete, childVisitErr := t.ensureVisited(toVisitNode, currentPath.Child(components[i]), components, i+1, visitFn)
if childVisitErr != nil {
return false, childVisitErr
}
if canDelete {
// fmt.Printf(" delete %v %v\n", currentPath, components[i])
delete(n.Children, components[i])
if len(n.Children) == 0 {
// fmt.Printf(" canDelete %v\n", currentPath)
return true, nil
}
}
return false, nil
}
func (n *Node) isVisited() bool {
if n == nil {
return true
}
if len(n.Children) > 0 {
return true
}
return false
}
func (n *Node) getChild(childName string) *Node {
if n == nil {
return nil
}
if len(n.Children) > 0 {
return n.Children[childName]
}
return nil
}
func (t *BoundedTree) HasVisited(p util.FullPath) bool {
t.RLock()
defer t.RUnlock()
if t.root == nil {
return true
}
components := p.Split()
// fmt.Printf("components %v %d\n", components, len(components))
return t.hasVisited(t.root, util.FullPath("/"), components, 0)
}
func (t *BoundedTree) hasVisited(n *Node, currentPath util.FullPath, components []string, i int) bool {
if n == nil {
return true
}
if !n.isVisited() {
return false
}
// fmt.Printf(" hasVisited child %v %+v %d\n", currentPath, components, i)
if i >= len(components) {
return true
}
toVisitNode, found := n.Children[components[i]]
if !found {
return true
}
return t.hasVisited(toVisitNode, currentPath.Child(components[i]), components, i+1)
}
|
