swarm: codebase split from go-ethereum (#1405)

state/dbstore.go

@@ -0,0 +1,111 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package state
+
+import (
+	"encoding"
+	"encoding/json"
+	"errors"
+
+	"github.com/syndtr/goleveldb/leveldb"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+)
+
+// ErrNotFound is returned when no results are returned from the database
+var ErrNotFound = errors.New("ErrorNotFound")
+
+// Store defines methods required to get, set, delete values for different keys
+// and close the underlying resources.
+type Store interface {
+	Get(key string, i interface{}) (err error)
+	Put(key string, i interface{}) (err error)
+	Delete(key string) (err error)
+	Close() error
+}
+
+// DBStore uses LevelDB to store values.
+type DBStore struct {
+	db *leveldb.DB
+}
+
+// NewDBStore creates a new instance of DBStore.
+func NewDBStore(path string) (s *DBStore, err error) {
+	db, err := leveldb.OpenFile(path, nil)
+	if err != nil {
+		return nil, err
+	}
+	return &DBStore{
+		db: db,
+	}, nil
+}
+
+// NewInmemoryStore returns a new instance of DBStore. To be used only in tests and simulations.
+func NewInmemoryStore() *DBStore {
+	db, err := leveldb.Open(storage.NewMemStorage(), nil)
+	if err != nil {
+		panic(err)
+	}
+	return &DBStore{
+		db: db,
+	}
+}
+
+// Get retrieves a persisted value for a specific key. If there is no results
+// ErrNotFound is returned. The provided parameter should be either a byte slice or
+// a struct that implements the encoding.BinaryUnmarshaler interface
+func (s *DBStore) Get(key string, i interface{}) (err error) {
+	has, err := s.db.Has([]byte(key), nil)
+	if err != nil || !has {
+		return ErrNotFound
+	}
+
+	data, err := s.db.Get([]byte(key), nil)
+	if err == leveldb.ErrNotFound {
+		return ErrNotFound
+	}
+
+	unmarshaler, ok := i.(encoding.BinaryUnmarshaler)
+	if !ok {
+		return json.Unmarshal(data, i)
+	}
+	return unmarshaler.UnmarshalBinary(data)
+}
+
+// Put stores an object that implements Binary for a specific key.
+func (s *DBStore) Put(key string, i interface{}) (err error) {
+	var bytes []byte
+	if marshaler, ok := i.(encoding.BinaryMarshaler); ok {
+		if bytes, err = marshaler.MarshalBinary(); err != nil {
+			return err
+		}
+	} else {
+		if bytes, err = json.Marshal(i); err != nil {
+			return err
+		}
+	}
+	return s.db.Put([]byte(key), bytes, nil)
+}
+
+// Delete removes entries stored under a specific key.
+func (s *DBStore) Delete(key string) (err error) {
+	return s.db.Delete([]byte(key), nil)
+}
+
+// Close releases the resources used by the underlying LevelDB.
+func (s *DBStore) Close() error {
+	return s.db.Close()
+}

state/dbstore_test.go

@@ -0,0 +1,125 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package state
+
+import (
+	"bytes"
+	"errors"
+	"io/ioutil"
+	"os"
+	"strings"
+	"testing"
+)
+
+var ErrInvalidArraySize = errors.New("invalid byte array size")
+var ErrInvalidValuePersisted = errors.New("invalid value was persisted to the db")
+
+type SerializingType struct {
+	key   string
+	value string
+}
+
+func (st *SerializingType) MarshalBinary() (data []byte, err error) {
+	d := []byte(strings.Join([]string{st.key, st.value}, ";"))
+
+	return d, nil
+}
+
+func (st *SerializingType) UnmarshalBinary(data []byte) (err error) {
+	d := bytes.Split(data, []byte(";"))
+	l := len(d)
+	if l == 0 {
+		return ErrInvalidArraySize
+	}
+	if l == 2 {
+		keyLen := len(d[0])
+		st.key = string(d[0][:keyLen])
+
+		valLen := len(d[1])
+		st.value = string(d[1][:valLen])
+	}
+
+	return nil
+}
+
+// TestDBStore tests basic functionality of DBStore.
+func TestDBStore(t *testing.T) {
+	dir, err := ioutil.TempDir("", "db_store_test")
+	if err != nil {
+		panic(err)
+	}
+	defer os.RemoveAll(dir)
+
+	store, err := NewDBStore(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	testStore(t, store)
+
+	store.Close()
+
+	persistedStore, err := NewDBStore(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer persistedStore.Close()
+
+	testPersistedStore(t, persistedStore)
+}
+
+func testStore(t *testing.T, store Store) {
+	ser := &SerializingType{key: "key1", value: "value1"}
+	jsonify := []string{"a", "b", "c"}
+
+	err := store.Put(ser.key, ser)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = store.Put("key2", jsonify)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+}
+
+func testPersistedStore(t *testing.T, store Store) {
+	ser := &SerializingType{}
+
+	err := store.Get("key1", ser)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if ser.key != "key1" || ser.value != "value1" {
+		t.Fatal(ErrInvalidValuePersisted)
+	}
+
+	as := []string{}
+	err = store.Get("key2", &as)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(as) != 3 {
+		t.Fatalf("serialized array did not match expectation")
+	}
+	if as[0] != "a" || as[1] != "b" || as[2] != "c" {
+		t.Fatalf("elements serialized did not match expected values")
+	}
+}