From e3ec2ff16c41bd928013a390f91cc1d9f4fd7eb4 Mon Sep 17 00:00:00 2001
From: Jim Myhrberg <contact@jimeh.me>
Date: Mon, 11 Jul 2016 14:11:38 +0100
Subject: [PATCH] Add very basic in-memory storage adapter

---
 storage/inmemory/store.go      |  69 ++++++++++++++
 storage/inmemory/store_test.go | 164 +++++++++++++++++++++++++++++++++
 2 files changed, 233 insertions(+)
 create mode 100644 storage/inmemory/store.go
 create mode 100644 storage/inmemory/store_test.go

diff --git a/storage/inmemory/store.go b/storage/inmemory/store.go
new file mode 100644
index 0000000..a350456
--- /dev/null
+++ b/storage/inmemory/store.go
@@ -0,0 +1,69 @@
+package inmemory
+
+import (
+	"errors"
+	"sync"
+)
+
+// ErrNotFound is returned when Get() tries to fetch a non-existent key.
+var ErrNotFound = errors.New("not found")
+
+// New creates a new Store using given path to persist data.
+func New() (*Store, error) {
+	store := &Store{
+		Data:     map[string][]byte{},
+		Sequence: 0,
+	}
+	return store, nil
+}
+
+// Store allows storing data into a in-memory map.
+type Store struct {
+	sync.RWMutex
+	Data     map[string][]byte
+	Sequence int
+	Closed   bool
+}
+
+// Close database.
+func (s *Store) Close() error {
+	s.Data = make(map[string][]byte)
+	s.Sequence = 0
+	return nil
+}
+
+// Get a given key's value.
+func (s *Store) Get(key []byte) ([]byte, error) {
+	s.RLock()
+	value := s.Data[string(key)]
+	s.RUnlock()
+	if value == nil {
+		return nil, ErrNotFound
+	}
+	return value, nil
+}
+
+// Set a given key's to the specified value.
+func (s *Store) Set(key []byte, value []byte) error {
+	s.Lock()
+	s.Data[string(key)] = value
+	s.Unlock()
+	return nil
+}
+
+// Delete a given key.
+func (s *Store) Delete(key []byte) error {
+	s.Lock()
+	delete(s.Data, string(key))
+	s.Unlock()
+	return nil
+}
+
+// NextSequence returns a auto-incrementing int.
+func (s *Store) NextSequence() (int, error) {
+	s.Lock()
+	s.Sequence++
+	seq := s.Sequence
+	s.Unlock()
+	return seq, nil
+}
diff --git a/storage/inmemory/store_test.go b/storage/inmemory/store_test.go
new file mode 100644
index 0000000..a20b17b
--- /dev/null
+++ b/storage/inmemory/store_test.go
@@ -0,0 +1,164 @@
+package inmemory
+
+import (
+	"testing"
+
+	"github.com/jimeh/ozu.io/storage"
+	"github.com/stretchr/testify/suite"
+)
+
+// Setup Suite
+
+var examples = []struct {
+	key   []byte
+	value []byte
+}{
+	{key: []byte("hello"), value: []byte("world")},
+	{key: []byte("foo"), value: []byte("bar")},
+	{key: []byte("wtf"), value: []byte("dude")},
+}
+
+type StoreSuite struct {
+	suite.Suite
+	store *Store
+}
+
+func (s *StoreSuite) SetupTest() {
+	store, err := New()
+	s.Require().NoError(err)
+	s.store = store
+}
+
+func (s *StoreSuite) TearDownTest() {
+	_ = s.store.Close()
+}
+
+func (s *StoreSuite) Seed() {
+	for _, e := range examples {
+		s.store.Data[string(e.key)] = e.value
+	}
+}
+
+// Tests
+
+func (s *StoreSuite) TestStoreInterface() {
+	s.Implements(new(storage.Store), new(Store))
+}
+
+func (s *StoreSuite) TestSet() {
+	for _, e := range examples {
+		err := s.store.Set(e.key, e.value)
+		s.NoError(err)
+	}
+
+	for _, e := range examples {
+		result, _ := s.store.Data[string(e.key)]
+		s.Equal(e.value, result)
+	}
+}
+
+func (s *StoreSuite) TestGetExisting() {
+	s.Seed()
+
+	for _, e := range examples {
+		result, err := s.store.Get(e.key)
+		s.NoError(err)
+		s.Equal(e.value, result)
+	}
+}
+
+func (s *StoreSuite) TestGetNonExistant() {
+	result, err := s.store.Get([]byte("does-not-exist"))
+	s.Nil(result)
+	s.EqualError(err, "not found")
+}
+
+func (s *StoreSuite) TestDeleteExisting() {
+	s.Seed()
+
+	for _, e := range examples {
+		value := s.store.Data[string(e.key)]
+		s.Require().Equal(e.value, value)
+
+		value, err := s.store.Get(e.key)
+		s.Require().NoError(err)
+		s.Require().Equal(value, e.value)
+
+		err = s.store.Delete(e.key)
+		s.NoError(err)
+
+		value, err = s.store.Get(e.key)
+		s.Nil(value)
+		s.EqualError(err, "not found")
+
+		_, has := s.store.Data[string(e.key)]
+		s.Equal(false, has)
+	}
+}
+
+func (s *StoreSuite) TestDeleteNonExistant() {
+	err := s.store.Delete([]byte("does-not-exist"))
+	s.NoError(err)
+}
+
+func (s *StoreSuite) TestNextSequenceExisting() {
+	s.store.Sequence = 5
+
+	result, err := s.store.NextSequence()
+	s.NoError(err)
+	s.Equal(6, result)
+}
+
+func (s *StoreSuite) TestNextSequenceNonExistant() {
+	for i := 1; i < 10; i++ {
+		result, err := s.store.NextSequence()
+
+		s.NoError(err)
+		s.Equal(i, result)
+	}
+}
+
+// Run Suite
+
+func TestStoreSuite(t *testing.T) {
+	suite.Run(t, new(StoreSuite))
+}
+
+// Benchmarks
+
+func BenchmarkGet(b *testing.B) {
+	store, _ := New()
+
+	key := []byte("hello")
+	value := []byte("world")
+	_ = store.Set(key, value)
+
+	for n := 0; n < b.N; n++ {
+		_, _ = store.Get(key)
+	}
+
+	_ = store.Close()
+}
+
+func BenchmarkSet(b *testing.B) {
+	store, _ := New()
+
+	key := []byte("hello")
+	value := []byte("world")
+
+	for n := 0; n < b.N; n++ {
+		_ = store.Set(append(key, string(n)...), value)
+	}
+
+	_ = store.Close()
+}
+
+func BenchmarkNextSequence(b *testing.B) {
+	store, _ := New()
+
+	for n := 0; n < b.N; n++ {
+		_, _ = store.NextSequence()
+	}
+
+	_ = store.Close()
+}