go-ethereum/swarm/storage/netstore.go
2018-01-23 17:50:32 +01:00

78 lines
2.1 KiB
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 (
"time"
)
// NetStore implements the ChunkStore interface,
// this chunk access layer assumed 2 chunk stores
// local storage eg. LocalStore and network storage eg., NetStore
// access by calling network is blocking with a timeout
type NetStore struct {
localStore *LocalStore
retrieve func(chunk *Chunk) error
}
func NewNetStore(localStore *LocalStore, retrieve func(chunk *Chunk) error) *NetStore {
return &NetStore{localStore, retrieve}
}
// Get is the entrypoint for local retrieve requests
// waits for response or times out
func (self *NetStore) Get(key Key) (chunk *Chunk, err error) {
if self.retrieve == nil {
chunk, err = self.localStore.Get(key)
if err == nil {
return chunk, nil
}
if err != ErrFetching {
return nil, err
}
} else {
var created bool
chunk, created = self.localStore.GetOrCreateRequest(key)
if chunk.ReqC == nil {
return chunk, nil
}
if created {
if err := self.retrieve(chunk); err != nil {
return nil, err
}
}
}
t := time.NewTicker(searchTimeout)
defer t.Stop()
select {
case <-t.C:
return nil, ErrNotFound
case <-chunk.ReqC:
}
return chunk, nil
}
// Put is the entrypoint for local store requests coming from storeLoop
func (self *NetStore) Put(chunk *Chunk) {
self.localStore.Put(chunk)
}
// Close chunk store
func (self *NetStore) Close() {}