path: root/ethdb/memory_database.go

// Copyright 2014 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 ethdb

import (
    "errors"
    "sync"

    "github.com/dexon-foundation/dexon/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 {
    return &MemDatabase{
        db: make(map[string][]byte),
    }
}

func NewMemDatabaseWithCap(size int) *MemDatabase {
    return &MemDatabase{
        db: make(map[string][]byte, size),
    }
}

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) 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 common.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) 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
    del  bool
}

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

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

func (b *memBatch) Delete(key []byte) error {
    b.writes = append(b.writes, kv{common.CopyBytes(key), nil, true})
    b.size += 1
    return nil
}

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

    for _, kv := range b.writes {
        if kv.del {
            delete(b.db.db, string(kv.k))
            continue
        }
        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
}