1 files changed, 42 insertions, 0 deletions
diff --git a/trie/cache.go b/trie/cache.go
new file mode 100644
index 000000000..e03702b25
--- /dev/null
+++ b/trie/cache.go
@@ -0,0 +1,42 @@
+package trie
+
+type Backend interface {
+	Get([]byte) ([]byte, error)
+	Put([]byte, []byte)
+}
+
+type Cache struct {
+	store   map[string][]byte
+	backend Backend
+}
+
+func NewCache(backend Backend) *Cache {
+	return &Cache{make(map[string][]byte), backend}
+}
+
+func (self *Cache) Get(key []byte) []byte {
+	data := self.store[string(key)]
+	if data == nil {
+		data, _ = self.backend.Get(key)
+	}
+
+	return data
+}
+
+func (self *Cache) Put(key []byte, data []byte) {
+	self.store[string(key)] = data
+}
+
+func (self *Cache) Flush() {
+	for k, v := range self.store {
+		self.backend.Put([]byte(k), v)
+	}
+
+	// This will eventually grow too large. We'd could
+	// do a make limit on storage and push out not-so-popular nodes.
+	//self.Reset()
+}
+
+func (self *Cache) Reset() {
+	self.store = make(map[string][]byte)
+}