Golang levigo.DB類代碼示例

func getPlaylistFromDB(db *levigo.DB) []playListItem {
	log.Println("Loading Playlist from file...")

	ro := levigo.NewReadOptions()

	data, err := db.Get(ro, []byte("playlist"))
	if err != nil {
		log.Fatal(err)
	}

	p := bytes.NewBuffer(data)

	dec := gob.NewDecoder(p)

	var playlist []playListItem
	//we must decode into a pointer, so we'll take the address of e
	err = dec.Decode(&playlist)
	if err != nil {
		log.Print(err)
		playlist = []playListItem{}
	}

	log.Println("Loaded ", len(playlist), " items into playlist")
	log.Println(playlist)
	return playlist

}

func AddProc(procID int, db *levigo.DB) error {
	ro := levigo.NewReadOptions()
	wo := levigo.NewWriteOptions()

	data, err := db.Get(ro, []byte("procs"))
	spdata := bytes.Split(data, []byte(":"))

	for i, e := range spdata {

		if string(e) != "" {
			fmt.Println("ProcID: #", i, string(e))
			pid, err := strconv.Atoi(string(e))
			if err != nil {
				return err
			}
			if pid == procID {
				return errors.New("Process already exists")
			}
			if isProcAlive(pid) == false {
				removeProc(pid, db)
			}
		}

		if err != nil {
			return err
		}
	}

	strdata := string(data)
	strdata = strdata + ":" + strconv.Itoa(procID)

	err = db.Put(wo, []byte("procs"), []byte(strdata))
	return err
}

func loadUsers(db *levigo.DB) map[string]User {
	log.Println("Loading Users from file...")

	ro := levigo.NewReadOptions()

	data, err := db.Get(ro, []byte("Users"))
	if err != nil {
		log.Fatal(err)
	}

	p := bytes.NewBuffer(data)

	dec := gob.NewDecoder(p)

	var users map[string]User
	//we must decode into a pointer, so we'll take the address of e
	err = dec.Decode(&users)
	if err != nil {
		log.Print(err)
		users = map[string]User{}
	}

	log.Println("Loaded ", len(users), " users")
	log.Printf("%+v", users)
	return users

}

func (ahr AddHashRequest) Execute(database *levigo.DB, ro *levigo.ReadOptions, wo *levigo.WriteOptions) (*kminvalues.KMinValues, error) {
	if ahr.Key == "" {
		return nil, NoKeySpecified
	}

	keyBytes := []byte(ahr.Key)

	data, err := database.Get(ro, keyBytes)
	if err != nil {
		return nil, err
	}

	kmv, err := kminvalues.KMinValuesFromBytes(data)
	if err != nil {
		if len(data) == 0 {
			kmv = kminvalues.NewKMinValues(*defaultSize)
		} else {
			return nil, err
		}
	}
	kmv.AddHash(ahr.Hash)

	err = database.Put(wo, keyBytes, kmv.Bytes())
	return kmv, err
}

// Fetch a Tx by hash
func GetTx(db *levigo.DB, txHash string) (tx *Tx, err error) {
	ro := levigo.NewReadOptions()
	defer ro.Close()
	txKey, blockErr := db.Get(ro, []byte(fmt.Sprintf("tx!%s", txHash)))
	if blockErr != nil {
		err = errors.New("Tx not found")
		return
	}

	txData, blockErr := db.Get(ro, txKey)
	if blockErr != nil {
		err = errors.New("Tx not found")
		return
	}

	tx = new(Tx)
	err = json.Unmarshal(txData, tx)
	if err != nil {
		return
	}

	for txo_index, txo := range tx.TxOuts {
		txo.Spent, _ = GetTxoSpent(db, txo.Addr, tx.Hash, txo_index)
	}

	return
}

// Return the last height processed
func GetLastHeight(db *levigo.DB) (lastHeight uint, err error) {
	ro := levigo.NewReadOptions()
	defer ro.Close()
	lastHeightRaw, _ := db.Get(ro, []byte("last-height"))
	lastHeightInt, _ := strconv.Atoi(string(lastHeightRaw[:]))
	lastHeight = uint(lastHeightInt)
	return
}

func removeProc(pid int, db *levigo.DB) error {
	wo := levigo.NewWriteOptions()
	err := db.Delete(wo, []byte(strconv.Itoa(pid)))
	if err != nil {
		return err
	}
	return killProc(pid)

}

// Write the datastore version to a shard.
func writeDataStoreVersion(store *dataStore, ldb *levigo.DB, v uint32) error {
	w := new(bytes.Buffer)
	encoder := gob.NewEncoder(w)
	err := encoder.Encode(&v)
	if err != nil {
		return err
	}
	return ldb.Put(store.writeOpts, []byte{VERSION_KEY}, w.Bytes())
}

func (sr SetRequest) Execute(database *levigo.DB, ro *levigo.ReadOptions, wo *levigo.WriteOptions) (*KMinValues, error) {
	if sr.Key == "" {
		return nil, NoKeySpecified
	}

	keyBytes := []byte(sr.Key)
	err := database.Put(wo, keyBytes, sr.Kmv.Bytes())

	return sr.Kmv, err
}

func AddIndex(index [2]string, key []byte, indexDb *levigo.DB, wb *levigo.WriteBatch) error {
	searchKey := []byte(index[0] + "~" + index[1])
	keys, err := indexDb.Get(LReadOptions, searchKey)
	if err != nil {
		return err
	}
	keys = appendDataKey(keys, key)
	wb.Put(searchKey, keys)
	return nil
}

/*
DelKey deletes key from provided DB handle.
*/
func DelKey(key string, db *levigo.DB) bool {
	writer := levigo.NewWriteOptions()
	defer writer.Close()

	err := db.Delete(writer, []byte(key))
	if err != nil {
		golerror.Boohoo("Key "+key+" query failed.", false)
		return false
	}
	return true
}

/*
GetVal gets value of Key from provided db handle.
*/
func GetVal(key string, db *levigo.DB) string {
	reader := levigo.NewReadOptions()
	defer reader.Close()

	data, err := db.Get(reader, []byte(key))
	if err != nil {
		golerror.Boohoo("Key "+key+" query failed.", false)
		return ""
	}
	return string(data)
}

func writeUsersToDB(db *levigo.DB, users map[string]User) {
	wo := levigo.NewWriteOptions()
	m := new(bytes.Buffer)
	enc := gob.NewEncoder(m)
	enc.Encode(users)

	err := db.Put(wo, []byte("Users"), m.Bytes())
	if err != nil {
		log.Fatal(err)
	}
	wo.Close()
}

func writePlaylistToDB(db *levigo.DB, playlist []playListItem) {
	wo := levigo.NewWriteOptions()
	m := new(bytes.Buffer)
	enc := gob.NewEncoder(m)
	enc.Encode(playlist)

	err := db.Put(wo, []byte("playlist"), m.Bytes())
	if err != nil {
		log.Fatal(err)
	}
	wo.Close()
}

/*
PushKeyVal push KeyVal in provided DB handle.
*/
func PushKeyVal(key string, val string, db *levigo.DB) bool {
	writer := levigo.NewWriteOptions()
	defer writer.Close()

	keyname := []byte(key)
	value := []byte(val)
	err := db.Put(writer, keyname, value)
	if err != nil {
		golerror.Boohoo("Key "+key+" insertion failed. It's value was "+val, false)
		return false
	}
	return true
}