path: root/trie/cache.go

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) Copy() *Cache {
    cache := NewCache(self.backend)
    for k, v := range self.store {
        cache.store[k] = v
    }
    return cache
}

func (self *Cache) Reset() {
    //self.store = make(map[string][]byte)
}