// Copyright 2018 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/>.
// memory storage layer for the package blockhash
package storage
import (
"context"
"sync"
lru "github.com/hashicorp/golang-lru"
)
type MemStore struct {
cache *lru.Cache
requests *lru.Cache
mu sync.RWMutex
disabled bool
}
//NewMemStore is instantiating a MemStore cache. We are keeping a record of all outgoing requests for chunks, that
//should later be delivered by peer nodes, in the `requests` LRU cache. We are also keeping all frequently requested
//chunks in the `cache` LRU cache.
//
//`requests` LRU cache capacity should ideally never be reached, this is why for the time being it should be initialised
//with the same value as the LDBStore capacity.
func NewMemStore(params *StoreParams, _ *LDBStore) (m *MemStore) {
if params.CacheCapacity == 0 {
return &MemStore{
disabled: true,
}
}
onEvicted := func(key interface{}, value interface{}) {
v := value.(*Chunk)
<-v.dbStoredC
}
c, err := lru.NewWithEvict(int(params.CacheCapacity), onEvicted)
if err != nil {
panic(err)
}
requestEvicted := func(key interface{}, value interface{}) {
// temporary remove of the error log, until we figure out the problem, as it is too spamy
//log.Error("evict called on outgoing request")
}
r, err := lru.NewWithEvict(int(params.ChunkRequestsCacheCapacity), requestEvicted)
if err != nil {
panic(err)
}
return &MemStore{
cache: c,
requests: r,
}
}
func (m *MemStore) Get(ctx context.Context, addr Address) (*Chunk, error) {
if m.disabled {
return nil, ErrChunkNotFound
}
m.mu.RLock()
defer m.mu.RUnlock()
r, ok := m.requests.Get(string(addr))
// it is a request
if ok {
return r.(*Chunk), nil
}
// it is not a request
c, ok := m.cache.Get(string(addr))
if !ok {
return nil, ErrChunkNotFound
}
return c.(*Chunk), nil
}
func (m *MemStore) Put(ctx context.Context, c *Chunk) {
if m.disabled {
return
}
m.mu.Lock()
defer m.mu.Unlock()
// it is a request
if c.ReqC != nil {
select {
case <-c.ReqC:
if c.GetErrored() != nil {
m.requests.Remove(string(c.Addr))
return
}
m.cache.Add(string(c.Addr), c)
m.requests.Remove(string(c.Addr))
default:
m.requests.Add(string(c.Addr), c)
}
return
}
// it is not a request
m.cache.Add(string(c.Addr), c)
m.requests.Remove(string(c.Addr))
}
func (m *MemStore) setCapacity(n int) {
if n <= 0 {
m.disabled = true
} else {
onEvicted := func(key interface{}, value interface{}) {
v := value.(*Chunk)
<-v.dbStoredC
}
c, err := lru.NewWithEvict(n, onEvicted)
if err != nil {
panic(err)
}
r, err := lru.New(defaultChunkRequestsCacheCapacity)
if err != nil {
panic(err)
}
m = &MemStore{
cache: c,
requests: r,
}
}
}
func (s *MemStore) Close() {}