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208 lines
3.6 KiB
208 lines
3.6 KiB
package db
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import (
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"bytes"
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"fmt"
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"sync"
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)
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func init() {
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registerDBCreator(MemDBBackendStr, func(name string, dir string) (DB, error) {
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return NewMemDB(), nil
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}, false)
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}
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type MemDB struct {
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mtx sync.Mutex
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db map[string][]byte
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}
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func NewMemDB() *MemDB {
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database := &MemDB{
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db: make(map[string][]byte),
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}
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return database
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}
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func (db *MemDB) Get(key []byte) []byte {
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db.mtx.Lock()
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defer db.mtx.Unlock()
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return db.db[string(key)]
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}
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func (db *MemDB) Has(key []byte) bool {
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db.mtx.Lock()
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defer db.mtx.Unlock()
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_, ok := db.db[string(key)]
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return ok
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}
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func (db *MemDB) Set(key []byte, value []byte) {
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db.mtx.Lock()
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defer db.mtx.Unlock()
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db.SetNoLock(key, value)
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}
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func (db *MemDB) SetSync(key []byte, value []byte) {
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db.mtx.Lock()
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defer db.mtx.Unlock()
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db.SetNoLock(key, value)
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}
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// NOTE: Implements atomicSetDeleter
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func (db *MemDB) SetNoLock(key []byte, value []byte) {
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if value == nil {
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value = []byte{}
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}
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db.db[string(key)] = value
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}
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func (db *MemDB) Delete(key []byte) {
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db.mtx.Lock()
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defer db.mtx.Unlock()
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delete(db.db, string(key))
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}
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func (db *MemDB) DeleteSync(key []byte) {
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db.mtx.Lock()
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defer db.mtx.Unlock()
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delete(db.db, string(key))
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}
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// NOTE: Implements atomicSetDeleter
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func (db *MemDB) DeleteNoLock(key []byte) {
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delete(db.db, string(key))
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}
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func (db *MemDB) Close() {
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// Close is a noop since for an in-memory
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// database, we don't have a destination
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// to flush contents to nor do we want
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// any data loss on invoking Close()
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// See the discussion in https://github.com/tendermint/tmlibs/pull/56
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}
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func (db *MemDB) Print() {
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db.mtx.Lock()
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defer db.mtx.Unlock()
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for key, value := range db.db {
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fmt.Printf("[%X]:\t[%X]\n", []byte(key), value)
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}
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}
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func (db *MemDB) Stats() map[string]string {
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db.mtx.Lock()
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defer db.mtx.Unlock()
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stats := make(map[string]string)
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stats["database.type"] = "memDB"
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stats["database.size"] = fmt.Sprintf("%d", len(db.db))
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return stats
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}
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func (db *MemDB) NewBatch() Batch {
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db.mtx.Lock()
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defer db.mtx.Unlock()
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return &memBatch{db, nil}
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}
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func (db *MemDB) Mutex() *sync.Mutex {
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return &(db.mtx)
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}
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//----------------------------------------
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func (db *MemDB) Iterator(start, end []byte) Iterator {
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/*
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XXX
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it := newMemDBIterator()
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it.db = db
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it.cur = 0
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db.mtx.Lock()
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defer db.mtx.Unlock()
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// We need a copy of all of the keys.
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// Not the best, but probably not a bottleneck depending.
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for key, _ := range db.db {
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it.keys = append(it.keys, key)
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}
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sort.Strings(it.keys)
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return it
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*/
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return nil
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}
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func (db *MemDB) ReverseIterator(start, end []byte) Iterator {
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// XXX
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return nil
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}
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type memDBIterator struct {
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cur int
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keys []string
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db DB
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}
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func newMemDBIterator() *memDBIterator {
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return &memDBIterator{}
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}
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func (it *memDBIterator) Seek(key []byte) {
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for i, ik := range it.keys {
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it.cur = i
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if bytes.Compare(key, []byte(ik)) <= 0 {
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return
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}
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}
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it.cur += 1 // If not found, becomes invalid.
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}
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func (it *memDBIterator) Valid() bool {
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return 0 <= it.cur && it.cur < len(it.keys)
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}
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func (it *memDBIterator) Next() {
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if !it.Valid() {
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panic("memDBIterator Next() called when invalid")
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}
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it.cur++
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}
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func (it *memDBIterator) Prev() {
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if !it.Valid() {
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panic("memDBIterator Next() called when invalid")
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}
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it.cur--
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}
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func (it *memDBIterator) Key() []byte {
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if !it.Valid() {
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panic("memDBIterator Key() called when invalid")
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}
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return []byte(it.keys[it.cur])
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}
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func (it *memDBIterator) Value() []byte {
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if !it.Valid() {
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panic("memDBIterator Value() called when invalid")
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}
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return it.db.Get(it.Key())
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}
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func (it *memDBIterator) Close() {
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it.db = nil
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it.keys = nil
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}
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func (it *memDBIterator) GetError() error {
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return nil
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}
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