mirror of
https://github.com/ethereum/go-ethereum.git
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140 lines
3.4 KiB
Go
140 lines
3.4 KiB
Go
// Copyright 2014 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package ethdb
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import (
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"errors"
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"sync"
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"github.com/ethereum/go-ethereum/common"
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)
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// MemDatabase is an in-memory key-value store.
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type MemDatabase struct {
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db map[string][]byte
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lock sync.RWMutex
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}
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// NewMemDatabase creates an in-memory key-value store.
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func NewMemDatabase() *MemDatabase {
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return &MemDatabase{
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db: make(map[string][]byte),
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}
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}
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// NewMemDatabaseWithCap creates an in-memory key-value store with a specific
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// starting capacity item.
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func NewMemDatabaseWithCap(size int) *MemDatabase {
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return &MemDatabase{
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db: make(map[string][]byte, size),
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}
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}
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// Put sets the value of the key.
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func (db *MemDatabase) Put(key []byte, value []byte) error {
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db.lock.Lock()
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defer db.lock.Unlock()
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db.db[string(key)] = common.CopyBytes(value)
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return nil
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}
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// Has checks if a given key exists.
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func (db *MemDatabase) Has(key []byte) (bool, error) {
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db.lock.RLock()
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defer db.lock.RUnlock()
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_, ok := db.db[string(key)]
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return ok, nil
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}
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// Get retrieves the value associated with a given key.
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func (db *MemDatabase) Get(key []byte) ([]byte, error) {
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db.lock.RLock()
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defer db.lock.RUnlock()
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if entry, ok := db.db[string(key)]; ok {
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return common.CopyBytes(entry), nil
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}
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return nil, errors.New("not found")
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}
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// Keys returns a list of all the keys present in the database.
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func (db *MemDatabase) Keys() [][]byte {
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db.lock.RLock()
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defer db.lock.RUnlock()
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keys := [][]byte{}
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for key := range db.db {
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keys = append(keys, []byte(key))
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}
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return keys
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}
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// Delete removes the specified entry from the database.
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func (db *MemDatabase) Delete(key []byte) error {
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db.lock.Lock()
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defer db.lock.Unlock()
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delete(db.db, string(key))
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return nil
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}
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// Close implements the closer interface. For the memory database, this is a noop.
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func (db *MemDatabase) Close() {}
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// NewBatch creates a memory buffer to group together database writes and flush
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// them out in one go. Batches are not atomic, just an performance optimization.
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func (db *MemDatabase) NewBatch() Batch {
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return &memBatch{db: db}
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}
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// Len returns the number of entries in the database.
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func (db *MemDatabase) Len() int { return len(db.db) }
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type kv struct{ k, v []byte }
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type memBatch struct {
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db *MemDatabase
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writes []kv
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size int
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}
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func (b *memBatch) Put(key, value []byte) error {
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b.writes = append(b.writes, kv{common.CopyBytes(key), common.CopyBytes(value)})
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b.size += len(value)
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return nil
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}
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func (b *memBatch) Write() error {
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b.db.lock.Lock()
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defer b.db.lock.Unlock()
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for _, kv := range b.writes {
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b.db.db[string(kv.k)] = kv.v
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}
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return nil
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}
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func (b *memBatch) ValueSize() int {
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return b.size
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}
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func (b *memBatch) Reset() {
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b.writes = b.writes[:0]
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b.size = 0
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}
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