removed last-key from lrange if there is no limit needed

Author: alash3al

README.md

@@ -19,7 +19,7 @@ Features
 =========
 - Core data structure: `KV`, `List`, `Hashmap` with advanced implementations.
 - Advanced Publish/Subscribe using webhook and websocket!
-- Pluggable Storage Engine (`badgerdb`, `boltdb`, `leveldb`)
+- Pluggable Storage Engine (`badgerdb`, `boltdb`, `leveldb`, `null`, `sqlite`)
 - Very compatible with any `redis client` including `redis-cli`
 - Standalone with no external dependencies
 - Helpers commands for `Time`, `Encode <hex|md5|sha1|sha256|sha512> <payload>`, `RANDINT`, `RANDSTR`
@@ -202,11 +202,12 @@ TODO
 - [x] PubSub Commands
 - [x] Utils Commands
 - [x] Adding BoltDB engine
+- [x] Adding LevelDB engine
+- [x] Adding Null engine
+- [x] Adding SQLite engine
+- [x] Adding TiKV engine
 - [ ] Adding RAM engine
 - [ ] Writing MyOwn DB Engine 
-- [ ] Writing Test Cases
-- [ ] Document/JSON Commands
-- [ ] GIS Commands
 
 License
 =======

commands_list.go

@@ -137,12 +137,14 @@ func lrangeCommand(c Context) {
 
 	lastKey = hex.EncodeToString([]byte(lastKey))
 
-	c.WriteArray(2)
+	if limit > 0 {
+		c.WriteArray(2)
 
-	if lastKey != "" {
-		c.WriteBulkString(lastKey)
-	} else {
-		c.WriteNull()
+		if lastKey != "" {
+			c.WriteBulkString(lastKey)
+		} else {
+			c.WriteNull()
+		}
 	}
 
 	c.WriteArray(len(data) / 2)

kvstore/tikv/leveldb.go

@@ -0,0 +1,207 @@
+// Copyright 2018 The Redix Authors. All rights reserved.
+// Use of this source code is governed by a Apache 2.0
+// license that can be found in the LICENSE file.
+//
+// tikv is a db engine based on tikv
+package tikv
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/pingcap/tidb/store/tikv"
+	"github.com/syndtr/goleveldb/leveldb"
+	"github.com/syndtr/goleveldb/leveldb/iterator"
+	"github.com/syndtr/goleveldb/leveldb/util"
+
+	"github.com/alash3al/redix/kvstore"
+)
+
+// TiKV - represents a TiKV implementation
+type TiKV struct {
+	// db *store
+	sync.RWMutex
+}
+
+// OpenLevelDB - Opens the specified path
+func OpenLevelDB(path string) (*TiKV, error) {
+	driver := tikv.Driver{}
+	store, err := driver.Open(path)
+
+	return ldb, nil
+}
+
+// Size - returns the size of the database in bytes
+func (ldb *TiKV) Size() int64 {
+	return 0
+}
+
+// GC - runs the garbage collector
+func (ldb *TiKV) GC() error {
+	return nil
+}
+
+// Incr - increment the key by the specified value
+func (ldb *TiKV) Incr(k string, by int64) (int64, error) {
+	ldb.Lock()
+	defer ldb.Unlock()
+
+	val, err := ldb.get(k)
+	if err != nil {
+		val = ""
+	}
+
+	valInt, _ := strconv.ParseInt(val, 10, 64)
+	valInt += by
+
+	err = ldb.set(k, fmt.Sprintf("%d", valInt), -1)
+	if err != nil {
+		return 0, err
+	}
+
+	return valInt, nil
+}
+
+func (ldb *TiKV) set(k, v string, ttl int) error {
+	var expires int64
+	if ttl > 0 {
+		expires = time.Now().Add(time.Duration(ttl) * time.Millisecond).Unix()
+	}
+	v = strconv.Itoa(int(expires)) + ";" + v
+	return ldb.db.Put([]byte(k), []byte(v), nil)
+}
+
+// Set - sets a key with the specified value and optional ttl
+func (ldb *TiKV) Set(k, v string, ttl int) error {
+	return ldb.set(k, v, ttl)
+}
+
+// MSet - sets multiple key-value pairs
+func (ldb *TiKV) MSet(data map[string]string) error {
+	batch := new(leveldb.Batch)
+	for k, v := range data {
+		v = "0;" + v
+		batch.Put([]byte(k), []byte(v))
+	}
+	return ldb.db.Write(batch, nil)
+}
+
+func (ldb *TiKV) get(k string) (string, error) {
+	var data string
+	var err error
+
+	delete := false
+
+	item, err := ldb.db.Get([]byte(k), nil)
+	if err != nil {
+		return "", err
+	}
+
+	parts := strings.SplitN(string(item), ";", 2)
+	expires, actual := parts[0], parts[1]
+
+	if exp, _ := strconv.Atoi(expires); exp > 0 && int(time.Now().Unix()) >= exp {
+		delete = true
+		err = errors.New("key not found")
+	} else {
+		data = actual
+	}
+
+	if delete {
+		ldb.db.Delete([]byte(k), nil)
+		return data, errors.New("key not found")
+	}
+
+	return data, nil
+}
+
+// Get - fetches the value of the specified k
+func (ldb *TiKV) Get(k string) (string, error) {
+	return ldb.get(k)
+}
+
+// MGet - fetch multiple values of the specified keys
+func (ldb *TiKV) MGet(keys []string) (data []string) {
+	for _, key := range keys {
+		val, err := ldb.get(key)
+		if err != nil {
+			data = append(data, "")
+			continue
+		}
+		data = append(data, val)
+	}
+	return data
+}
+
+// TTL - returns the time to live of the specified key's value
+func (ldb *TiKV) TTL(key string) int64 {
+	item, err := ldb.db.Get([]byte(key), nil)
+	if err != nil {
+		return -2
+	}
+
+	parts := strings.SplitN(string(item), ";", 2)
+	exp, _ := strconv.Atoi(parts[0])
+	if exp == 0 {
+		return -1
+	}
+
+	now := time.Now().Unix()
+	if now >= int64(exp) {
+		return -2
+	}
+
+	return int64(exp) - now
+}
+
+// Del - removes key(s) from the store
+func (ldb *TiKV) Del(keys []string) error {
+	batch := new(leveldb.Batch)
+	for _, key := range keys {
+		batch.Delete([]byte(key))
+	}
+	return ldb.db.Write(batch, nil)
+}
+
+// Scan - iterate over the whole store using the handler function
+func (ldb *TiKV) Scan(scannerOpt kvstore.ScannerOptions) error {
+	var iter iterator.Iterator
+
+	if scannerOpt.Offset == "" {
+		iter = ldb.db.NewIterator(nil, nil)
+	} else {
+		iter = ldb.db.NewIterator(&util.Range{Start: []byte(scannerOpt.Offset)}, nil)
+		if !scannerOpt.IncludeOffset {
+			iter.Next()
+		}
+	}
+
+	valid := func(k []byte) bool {
+		if k == nil {
+			return false
+		}
+
+		if scannerOpt.Prefix != "" && !bytes.HasPrefix(k, []byte(scannerOpt.Prefix)) {
+			return false
+		}
+
+		return true
+	}
+
+	for iter.Next() {
+		key := iter.Key()
+		val := strings.SplitN(string(iter.Value()), ";", 2)[1]
+		if valid(key) && !scannerOpt.Handler(string(key), string(val)) {
+			break
+		}
+	}
+
+	iter.Release()
+
+	return iter.Error()
+}