1 files changed, 147 insertions, 0 deletions
diff --git a/weed/filesys/fscache.go b/weed/filesys/fscache.go
new file mode 100644
index 000000000..974f378c7
--- /dev/null
+++ b/weed/filesys/fscache.go
@@ -0,0 +1,147 @@
+package filesys
+
+import (
+	"github.com/chrislusf/seaweedfs/weed/util"
+	"github.com/seaweedfs/fuse/fs"
+)
+
+type FsCache struct {
+	root *FsNode
+}
+type FsNode struct {
+	parent   *FsNode
+	node     fs.Node
+	name     string
+	children map[string]*FsNode
+}
+
+func newFsCache(root fs.Node) *FsCache {
+	return &FsCache{
+		root: &FsNode{
+			node: root,
+		},
+	}
+}
+
+func (c *FsCache) GetFsNode(path util.FullPath) fs.Node {
+	t := c.root
+	for _, p := range path.Split() {
+		t = t.findChild(p)
+		if t == nil {
+			return nil
+		}
+	}
+	return t.node
+}
+
+func (c *FsCache) SetFsNode(path util.FullPath, node fs.Node) {
+	t := c.root
+	for _, p := range path.Split() {
+		t = t.ensureChild(p)
+	}
+	t.node = node
+}
+
+func (c *FsCache) EnsureFsNode(path util.FullPath, genNodeFn func() fs.Node) fs.Node {
+	t := c.GetFsNode(path)
+	if t != nil {
+		return t
+	}
+	t = genNodeFn()
+	c.SetFsNode(path, t)
+	return t
+}
+
+func (c *FsCache) DeleteFsNode(path util.FullPath) {
+	t := c.root
+	for _, p := range path.Split() {
+		t = t.findChild(p)
+		if t == nil {
+			return
+		}
+	}
+	if t.parent != nil {
+		t.parent.deleteChild(t.name)
+	}
+	t.deleteSelf()
+}
+
+// oldPath and newPath are full path including the new name
+func (c *FsCache) Move(oldPath util.FullPath, newPath util.FullPath) *FsNode {
+
+	// find old node
+	src := c.root
+	for _, p := range oldPath.Split() {
+		src = src.findChild(p)
+		if src == nil {
+			return src
+		}
+	}
+	if src.parent != nil {
+		src.parent.deleteChild(src.name)
+	}
+	src.parent = nil
+
+	// find new node
+	target := c.root
+	for _, p := range newPath.Split() {
+		target = target.ensureChild(p)
+	}
+	parent := target.parent
+	src.name = target.name
+	parent.deleteChild(target.name)
+
+	target.deleteSelf()
+
+	src.connectToParent(parent)
+
+	return src
+}
+
+func (n *FsNode) connectToParent(parent *FsNode) {
+	n.parent = parent
+	oldNode := parent.findChild(n.name)
+	if oldNode != nil {
+		oldNode.deleteSelf()
+	}
+	parent.children[n.name] = n
+}
+
+func (n *FsNode) findChild(name string) *FsNode {
+	child, found := n.children[name]
+	if found {
+		return child
+	}
+	return nil
+}
+
+func (n *FsNode) ensureChild(name string) *FsNode {
+	if n.children == nil {
+		n.children = make(map[string]*FsNode)
+	}
+	child, found := n.children[name]
+	if found {
+		return child
+	}
+	t := &FsNode{
+		parent:   n,
+		node:     nil,
+		name:     name,
+		children: nil,
+	}
+	n.children[name] = t
+	return t
+}
+
+func (n *FsNode) deleteChild(name string) {
+	delete(n.children, name)
+}
+
+func (n *FsNode) deleteSelf() {
+	for _, child := range n.children {
+		child.deleteSelf()
+	}
+	n.node = nil
+	n.parent = nil
+	n.children = nil
+}