memory_database.go

// Copyright (c) 2017-2019 The Qitmeer developers
//
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.

// The parts code inspired by
// http://github.com/go-ethereum/ethdb/leveldb/leveldb.go

package statedb

import (
	"errors"
	"github.com/Qitmeer/qng/common/util"
	"sync"
)

/*
 * 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 {
	return &MemDatabase{
		db: make(map[string][]byte),
	}
}

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

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

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

	_, ok := db.db[string(key)]
	return ok, nil
}

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

	if entry, ok := db.db[string(key)]; ok {
		return util.CopyBytes(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) Close() {}

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

func (db *MemDatabase) Len() int { return len(db.db) }

type kv struct{ k, v []byte }

type memBatch struct {
	db     *MemDatabase
	writes []kv
	size   int
}

func (b *memBatch) Put(key, value []byte) error {
	b.writes = append(b.writes, kv{util.CopyBytes(key), util.CopyBytes(value)})
	b.size += len(value)
	return nil
}

func (b *memBatch) Write() error {
	b.db.lock.Lock()
	defer b.db.lock.Unlock()

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

func (b *memBatch) ValueSize() int {
	return b.size
}

func (b *memBatch) Reset() {
	b.writes = b.writes[:0]
	b.size = 0
}