go-ethereum/ethdb/memory_database.go

// Copyright 2014 The go-ethereum Authors && Copyright 2015 go-expanse Authors
// This file is part of the go-expanse library.
//
// The go-expanse 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-expanse 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-expanse library. If not, see <http://www.gnu.org/licenses/>.

package ethdb

import (
	"errors"
	"fmt"
	"sync"

	"github.com/expanse-project/go-expanse/common"
)

/*
 * This is a test memory database. Do not use for any production it does not get persisted
 */
type MemDatabase struct {
	db   map[string][]byte
	lock sync.RWMutex
}

func NewMemDatabase() (*MemDatabase, error) {
	return &MemDatabase{
		db: make(map[string][]byte),
	}, nil
}

func (db *MemDatabase) Put(key []byte, value []byte) error {
	db.lock.Lock()
	defer db.lock.Unlock()

	db.db[string(key)] = common.CopyBytes(value)
	return nil
}

func (db *MemDatabase) Set(key []byte, value []byte) {
	db.lock.Lock()
	defer db.lock.Unlock()

	db.Put(key, value)
}

func (db *MemDatabase) Get(key []byte) ([]byte, error) {
	db.lock.RLock()
	defer db.lock.RUnlock()

	if entry, ok := db.db[string(key)]; ok {
		return entry, nil
	}
	return nil, errors.New("not found")
}

func (db *MemDatabase) Keys() [][]byte {
	db.lock.RLock()
	defer db.lock.RUnlock()

	keys := [][]byte{}
	for key, _ := range db.db {
		keys = append(keys, []byte(key))
	}
	return keys
}

/*
func (db *MemDatabase) GetKeys() []*common.Key {
	data, _ := db.Get([]byte("KeyRing"))

	return []*common.Key{common.NewKeyFromBytes(data)}
}
*/

func (db *MemDatabase) Delete(key []byte) error {
	db.lock.Lock()
	defer db.lock.Unlock()

	delete(db.db, string(key))
	return nil
}

func (db *MemDatabase) Print() {
	db.lock.RLock()
	defer db.lock.RUnlock()

	for key, val := range db.db {
		fmt.Printf("%x(%d): ", key, len(key))
		node := common.NewValueFromBytes(val)
		fmt.Printf("%q\n", node.Val)
	}
}

func (db *MemDatabase) Close() {
}

func (db *MemDatabase) LastKnownTD() []byte {
	data, _ := db.Get([]byte("LastKnownTotalDifficulty"))
	if len(data) == 0 || data == nil {
		data = []byte{0x0}
	}
	return data
}

func (db *MemDatabase) NewBatch() Batch {
	return &memBatch{db: db}
}

type kv struct{ k, v []byte }

type memBatch struct {
	db     *MemDatabase
	writes []kv
	lock   sync.RWMutex
}

func (b *memBatch) Put(key, value []byte) error {
	b.lock.Lock()
	defer b.lock.Unlock()

	b.writes = append(b.writes, kv{key, common.CopyBytes(value)})
	return nil
}

func (b *memBatch) Write() error {
	b.lock.RLock()
	defer b.lock.RUnlock()

	b.db.lock.Lock()
	defer b.db.lock.Unlock()

	for _, kv := range b.writes {
		b.db.db[string(kv.k)] = kv.v
	}
	return nil
}