// Copyright 2014 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
package trie
import (
"github.com/ethereum/go-ethereum/compression/rle"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/syndtr/goleveldb/leveldb"
)
type Backend interface {
Get([]byte) ([]byte, error)
Put([]byte, []byte) error
}
type Cache struct {
batch *leveldb.Batch
store map[string][]byte
backend Backend
}
func NewCache(backend Backend) *Cache {
return &Cache{new(leveldb.Batch), 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) {
// write the data to the ldb batch
self.batch.Put(key, rle.Compress(data))
self.store[string(key)] = data
}
// Flush flushes the trie to the backing layer. If this is a leveldb instance
// we'll use a batched write, otherwise we'll use regular put.
func (self *Cache) Flush() {
if db, ok := self.backend.(*ethdb.LDBDatabase); ok {
if err := db.LDB().Write(self.batch, nil); err != nil {
glog.Fatal("db write err:", err)
}
} else {
for k, v := range self.store {
self.backend.Put([]byte(k), v)
}
}
}
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)
}
