179 lines
3.5 KiB
Go
179 lines
3.5 KiB
Go
package leveldb
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import (
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"encoding/json"
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"github.com/jmhodges/levigo"
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)
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const defaultFilterBits int = 10
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type Config struct {
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Path string `json:"path"`
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Compression bool `json:"compression"`
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BlockSize int `json:"block_size"`
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WriteBufferSize int `json:"write_buffer_size"`
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CacheSize int `json:"cache_size"`
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}
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type DB struct {
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cfg *Config
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db *levigo.DB
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opts *levigo.Options
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//for default read and write options
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readOpts *levigo.ReadOptions
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writeOpts *levigo.WriteOptions
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iteratorOpts *levigo.ReadOptions
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cache *levigo.Cache
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filter *levigo.FilterPolicy
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}
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func OpenWithConfig(cfg *Config) (*DB, error) {
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db := new(DB)
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db.cfg = cfg
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db.opts = db.initOptions(cfg)
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db.readOpts = levigo.NewReadOptions()
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db.writeOpts = levigo.NewWriteOptions()
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db.iteratorOpts = levigo.NewReadOptions()
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db.iteratorOpts.SetFillCache(false)
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var err error
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db.db, err = levigo.Open(cfg.Path, db.opts)
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return db, err
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}
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func Open(configJson json.RawMessage) (*DB, error) {
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cfg := new(Config)
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err := json.Unmarshal(configJson, cfg)
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if err != nil {
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return nil, err
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}
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return OpenWithConfig(cfg)
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}
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func (db *DB) initOptions(cfg *Config) *levigo.Options {
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opts := levigo.NewOptions()
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opts.SetCreateIfMissing(true)
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if cfg.CacheSize > 0 {
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db.cache = levigo.NewLRUCache(cfg.CacheSize)
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opts.SetCache(db.cache)
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}
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//we must use bloomfilter
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db.filter = levigo.NewBloomFilter(defaultFilterBits)
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opts.SetFilterPolicy(db.filter)
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if !cfg.Compression {
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opts.SetCompression(levigo.NoCompression)
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}
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if cfg.BlockSize > 0 {
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opts.SetBlockSize(cfg.BlockSize)
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}
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if cfg.WriteBufferSize > 0 {
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opts.SetWriteBufferSize(cfg.WriteBufferSize)
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}
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return opts
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}
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func (db *DB) Close() {
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db.opts.Close()
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if db.cache != nil {
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db.cache.Close()
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}
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if db.filter != nil {
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db.filter.Close()
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}
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db.readOpts.Close()
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db.writeOpts.Close()
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db.iteratorOpts.Close()
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db.db.Close()
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db.db = nil
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}
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func (db *DB) Destroy() {
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db.Close()
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opts := levigo.NewOptions()
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defer opts.Close()
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levigo.DestroyDatabase(db.cfg.Path, opts)
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}
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func (db *DB) Clear() {
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it := db.Iterator(nil, nil, 0, 0, -1)
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for ; it.Valid(); it.Next() {
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db.Delete(it.Key())
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}
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}
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func (db *DB) Put(key, value []byte) error {
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return db.db.Put(db.writeOpts, key, value)
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}
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func (db *DB) Get(key []byte) ([]byte, error) {
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return db.db.Get(db.readOpts, key)
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}
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func (db *DB) Delete(key []byte) error {
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return db.db.Delete(db.writeOpts, key)
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}
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func (db *DB) NewWriteBatch() *WriteBatch {
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wb := new(WriteBatch)
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wb.wb = levigo.NewWriteBatch()
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wb.db = db
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return wb
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}
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//limit < 0, unlimit
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//offset must >= 0, if < 0, will get nothing
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func (db *DB) Iterator(min []byte, max []byte, rangeType uint8, offset int, limit int) *Iterator {
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return newIterator(db, db.iteratorOpts, NewRange(min, max, rangeType), offset, limit, IteratorForward)
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}
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//limit < 0, unlimit
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//offset must >= 0, if < 0, will get nothing
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func (db *DB) RevIterator(min []byte, max []byte, rangeType uint8, offset int, limit int) *Iterator {
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return newIterator(db, db.iteratorOpts, NewRange(min, max, rangeType), offset, limit, IteratorBackward)
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}
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func (db *DB) NewSnapshot() *Snapshot {
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return newSnapshot(db)
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}
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func (db *DB) GetInt(key []byte) (int64, error) {
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return Int(db.Get(key))
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}
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func (db *DB) GetUInt(key []byte) (uint64, error) {
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return Uint(db.Get(key))
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}
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func (db *DB) GetFloat(key []byte) (float64, error) {
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return Float(db.Get(key))
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}
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func (db *DB) GetString(key []byte) (string, error) {
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return String(db.Get(key))
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}
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func (db *DB) GetSlice(key []byte) ([]byte, error) {
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return Slice(db.Get(key))
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}
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