From 61918f7f99e99693e0cbdf5762f05453f0dcb7ff Mon Sep 17 00:00:00 2001
From: arnaucube <arnaucube@gmail.com>
Date: Sat, 6 Apr 2019 20:34:55 +0200
Subject: [PATCH] add leveldb as db

---
 README.md          |  2 +-
 db/leveldb.go      | 55 ++++++++++++++++++++++++++++++++++++++++++++++
 db/leveldb_test.go | 53 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 109 insertions(+), 1 deletion(-)
 create mode 100644 db/leveldb.go
 create mode 100644 db/leveldb_test.go

diff --git a/README.md b/README.md
index 26836c9..08c77ba 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 # slowlorisdb
 
-Slow and decentralized cryptographically consistent database
+Slow, decentralized and cryptographically consistent database
 
 ![slowloris](https://04019a5a-a-62cb3a1a-s-sites.googlegroups.com/site/jchristensensdigitalportfolio/slow-loris/IO-moth-eating-frozen-apple-sauce.jpg "slowloris")
diff --git a/db/leveldb.go b/db/leveldb.go
new file mode 100644
index 0000000..69e1f00
--- /dev/null
+++ b/db/leveldb.go
@@ -0,0 +1,55 @@
+package db
+
+import (
+	"github.com/syndtr/goleveldb/leveldb"
+)
+
+// Db is the database with the specified prefix
+type Db struct {
+	ldb    *leveldb.DB
+	prefix []byte
+}
+
+// New creates a new Db database
+func New(path string) (*Db, error) {
+	ldb, err := leveldb.OpenFile(path, nil)
+	if err != nil {
+		return nil, err
+	}
+	return &Db{ldb, []byte{}}, nil
+}
+
+// WithPrefix returns a subdatabase with the specified prefix
+func (db *Db) WithPrefix(prefix []byte) *Db {
+	return &Db{db.ldb, append(db.prefix, prefix...)}
+}
+
+// Put adds the key value to the database
+func (db *Db) Put(key, value []byte) error {
+	err := db.ldb.Put(append(db.prefix, key[:]...), value, nil)
+	return err
+}
+
+// Get retreives a value from the database for a given key
+func (db *Db) Get(key []byte) ([]byte, error) {
+	v, err := db.ldb.Get(append(db.prefix, key[:]...), nil)
+	if err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// Iterate iterates over the database
+func (db *Db) Iterate(f func([]byte, []byte)) error {
+	snapshot, err := db.ldb.GetSnapshot()
+	if err != nil {
+		return err
+	}
+	iter := snapshot.NewIterator(nil, nil)
+	for iter.Next() {
+		f(iter.Key(), iter.Value())
+	}
+	iter.Release()
+	err = iter.Error()
+	return err
+}
diff --git a/db/leveldb_test.go b/db/leveldb_test.go
new file mode 100644
index 0000000..28e4975
--- /dev/null
+++ b/db/leveldb_test.go
@@ -0,0 +1,53 @@
+package db
+
+import (
+	"io/ioutil"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/syndtr/goleveldb/leveldb/errors"
+)
+
+func TestNew(t *testing.T) {
+	dir, err := ioutil.TempDir("", "db")
+	assert.Nil(t, err)
+	_, err = New(dir)
+	assert.Nil(t, err)
+}
+func TestPutAndGet(t *testing.T) {
+	dir, err := ioutil.TempDir("", "db")
+	assert.Nil(t, err)
+	db, err := New(dir)
+	assert.Nil(t, err)
+
+	k := []byte("test key")
+	v := []byte("test value")
+
+	err = db.Put(k, v)
+	assert.Nil(t, err)
+
+	vg, err := db.Get(k)
+	assert.Nil(t, err)
+	assert.Equal(t, v, vg)
+
+}
+
+func TestPrefix(t *testing.T) {
+	dir, err := ioutil.TempDir("", "db")
+	assert.Nil(t, err)
+	db, err := New(dir)
+	assert.Nil(t, err)
+
+	dbPrefix := db.WithPrefix([]byte("prefix1"))
+
+	err = dbPrefix.Put([]byte("k1"), []byte("v1"))
+	assert.Nil(t, err)
+
+	_, err = db.Get([]byte("k1"))
+	assert.Equal(t, err, errors.ErrNotFound)
+
+	v1, err := dbPrefix.Get([]byte("k1"))
+	assert.Nil(t, err)
+	assert.Equal(t, []byte("v1"), v1)
+}