path: root/swarm/storage/localstore.go

// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library 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.
//
// The go-ethereum library 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 the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package storage

import (
    "encoding/binary"

    "github.com/ethereum/go-ethereum/metrics"
)

//metrics variables
var (
    dbStorePutCounter = metrics.NewRegisteredCounter("storage.db.dbstore.put.count", nil)
)

// LocalStore is a combination of inmemory db over a disk persisted db
// implements a Get/Put with fallback (caching) logic using any 2 ChunkStores
type LocalStore struct {
    memStore ChunkStore
    DbStore  ChunkStore
}

// This constructor uses MemStore and DbStore as components
func NewLocalStore(hash SwarmHasher, params *StoreParams) (*LocalStore, error) {
    dbStore, err := NewDbStore(params.ChunkDbPath, hash, params.DbCapacity, params.Radius)
    if err != nil {
        return nil, err
    }
    return &LocalStore{
        memStore: NewMemStore(dbStore, params.CacheCapacity),
        DbStore:  dbStore,
    }, nil
}

func (self *LocalStore) CacheCounter() uint64 {
    return uint64(self.memStore.(*MemStore).Counter())
}

func (self *LocalStore) DbCounter() uint64 {
    return self.DbStore.(*DbStore).Counter()
}

// LocalStore is itself a chunk store
// unsafe, in that the data is not integrity checked
func (self *LocalStore) Put(chunk *Chunk) {
    chunk.dbStored = make(chan bool)
    self.memStore.Put(chunk)
    if chunk.wg != nil {
        chunk.wg.Add(1)
    }
    go func() {
        dbStorePutCounter.Inc(1)
        self.DbStore.Put(chunk)
        if chunk.wg != nil {
            chunk.wg.Done()
        }
    }()
}

// Get(chunk *Chunk) looks up a chunk in the local stores
// This method is blocking until the chunk is retrieved
// so additional timeout may be needed to wrap this call if
// ChunkStores are remote and can have long latency
func (self *LocalStore) Get(key Key) (chunk *Chunk, err error) {
    chunk, err = self.memStore.Get(key)
    if err == nil {
        return
    }
    chunk, err = self.DbStore.Get(key)
    if err != nil {
        return
    }
    chunk.Size = int64(binary.LittleEndian.Uint64(chunk.SData[0:8]))
    self.memStore.Put(chunk)
    return
}

// Close local store
func (self *LocalStore) Close() {}