85 lines
1.9 KiB
Go
85 lines
1.9 KiB
Go
package node
|
|
|
|
import (
|
|
"container/list"
|
|
|
|
"github.com/lbryio/lbcd/claimtrie/change"
|
|
)
|
|
|
|
type cacheLeaf struct {
|
|
node *Node
|
|
element *list.Element
|
|
changes []change.Change
|
|
height int32
|
|
}
|
|
|
|
type Cache struct {
|
|
nodes map[string]*cacheLeaf
|
|
order *list.List
|
|
limit int
|
|
}
|
|
|
|
func (nc *Cache) insert(name []byte, n *Node, height int32) {
|
|
key := string(name)
|
|
|
|
existing := nc.nodes[key]
|
|
if existing != nil {
|
|
existing.node = n
|
|
existing.height = height
|
|
existing.changes = nil
|
|
nc.order.MoveToFront(existing.element)
|
|
return
|
|
}
|
|
|
|
for nc.order.Len() >= nc.limit {
|
|
// TODO: maybe ensure that we don't remove nodes that have a lot of changes?
|
|
delete(nc.nodes, nc.order.Back().Value.(string))
|
|
nc.order.Remove(nc.order.Back())
|
|
}
|
|
|
|
element := nc.order.PushFront(key)
|
|
nc.nodes[key] = &cacheLeaf{node: n, element: element, height: height}
|
|
}
|
|
|
|
func (nc *Cache) fetch(name []byte, height int32) (*Node, []change.Change, int32) {
|
|
key := string(name)
|
|
|
|
existing := nc.nodes[key]
|
|
if existing != nil && existing.height <= height {
|
|
nc.order.MoveToFront(existing.element)
|
|
return existing.node, existing.changes, existing.height
|
|
}
|
|
return nil, nil, -1
|
|
}
|
|
|
|
func (nc *Cache) addChanges(changes []change.Change, height int32) {
|
|
for _, c := range changes {
|
|
key := string(c.Name)
|
|
existing := nc.nodes[key]
|
|
if existing != nil && existing.height <= height {
|
|
existing.changes = append(existing.changes, c)
|
|
}
|
|
}
|
|
}
|
|
|
|
func (nc *Cache) drop(names [][]byte) {
|
|
for _, name := range names {
|
|
key := string(name)
|
|
existing := nc.nodes[key]
|
|
if existing != nil {
|
|
// we can't roll it backwards because we don't know its previous height value; just toast it
|
|
delete(nc.nodes, key)
|
|
nc.order.Remove(existing.element)
|
|
}
|
|
}
|
|
}
|
|
|
|
func (nc *Cache) clear() {
|
|
nc.nodes = map[string]*cacheLeaf{}
|
|
nc.order = list.New()
|
|
// we'll let the GC sort out the remains...
|
|
}
|
|
|
|
func NewCache(limit int) *Cache {
|
|
return &Cache{limit: limit, nodes: map[string]*cacheLeaf{}, order: list.New()}
|
|
}
|