From e08aa0f83206e88c7751aa4950561f7d8dd36dc5 Mon Sep 17 00:00:00 2001
From: Andrew Hust <andrew.hust@clickbank.com>
Date: Fri, 4 Nov 2016 15:01:03 -0600
Subject: [PATCH 1/2] added locking to mutation methods Store, DeleteOne and
 DeleteAll to InMemory storage

---
 memory.go      |  8 ++++++
 memory_test.go | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+)
 create mode 100644 memory_test.go

diff --git a/memory.go b/memory.go
index a603a4e..90764d6 100644
--- a/memory.go
+++ b/memory.go
@@ -2,6 +2,7 @@ package storage
 
 import (
 	"strings"
+	"sync"
 
 	"github.com/mailhog/data"
 )
@@ -10,6 +11,7 @@ import (
 type InMemory struct {
 	MessageIDIndex map[string]int
 	Messages       []*data.Message
+	mu             sync.Mutex
 }
 
 // CreateInMemory creates a new in memory storage backend
@@ -22,8 +24,10 @@ func CreateInMemory() *InMemory {
 
 // Store stores a message and returns its storage ID
 func (memory *InMemory) Store(m *data.Message) (string, error) {
+	memory.mu.Lock()
 	memory.Messages = append(memory.Messages, m)
 	memory.MessageIDIndex[string(m.ID)] = len(memory.Messages) - 1
+	memory.mu.Unlock()
 	return string(m.ID), nil
 }
 
@@ -156,6 +160,7 @@ func (memory *InMemory) List(start int, limit int) (*data.Messages, error) {
 
 // DeleteOne deletes an individual message by storage ID
 func (memory *InMemory) DeleteOne(id string) error {
+	memory.mu.Lock()
 	index := memory.MessageIDIndex[id]
 	delete(memory.MessageIDIndex, id)
 	for k, v := range memory.MessageIDIndex {
@@ -164,13 +169,16 @@ func (memory *InMemory) DeleteOne(id string) error {
 		}
 	}
 	memory.Messages = append(memory.Messages[:index], memory.Messages[index+1:]...)
+	memory.mu.Unlock()
 	return nil
 }
 
 // DeleteAll deletes all in memory messages
 func (memory *InMemory) DeleteAll() error {
+	memory.mu.Lock()
 	memory.Messages = make([]*data.Message, 0)
 	memory.MessageIDIndex = make(map[string]int)
+	memory.mu.Unlock()
 	return nil
 }
 
diff --git a/memory_test.go b/memory_test.go
new file mode 100644
index 0000000..fe52913
--- /dev/null
+++ b/memory_test.go
@@ -0,0 +1,75 @@
+package storage
+
+import (
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/mailhog/data"
+)
+
+func TestStore(t *testing.T) {
+	storage := CreateInMemory()
+
+	if storage.Count() != 0 {
+		t.Errorf("storage.Count() expected: %d, got: %d", 0, storage.Count())
+	}
+
+	var wg sync.WaitGroup
+	wg.Add(25)
+	for i := 0; i < 25; i++ {
+		go func(i int) {
+			msg := &data.Message{
+				ID:      data.MessageID(i),
+				Created: time.Now(),
+			}
+			storage.Store(msg)
+			wg.Done()
+		}(i)
+	}
+	wg.Wait()
+
+	if storage.Count() != 25 {
+		t.Errorf("storage.Count() expected: %d, got: %d", 25, storage.Count())
+	}
+}
+
+func TestDeleteAll(t *testing.T) {
+	storage := CreateInMemory()
+
+	if storage.Count() != 0 {
+		t.Errorf("storage.Count() expected: %d, got: %d", 0, storage.Count())
+	}
+
+	for i := 0; i < 25; i++ {
+		storage.Store(&data.Message{ID: data.MessageID(i), Created: time.Now()})
+	}
+
+	if storage.Count() != 25 {
+		t.Errorf("storage.Count() expected: %d, got: %d", 25, storage.Count())
+	}
+
+	storage.DeleteAll()
+
+	if storage.Count() != 0 {
+		t.Errorf("storage.Count() expected: %d, got: %d", 0, storage.Count())
+	}
+}
+
+func TestDeleteOne(t *testing.T) {
+	storage := CreateInMemory()
+
+	if storage.Count() != 0 {
+		t.Errorf("storage.Count() expected: %d, got: %d", 0, storage.Count())
+	}
+
+	for i := 0; i < 25; i++ {
+		storage.Store(&data.Message{ID: data.MessageID(i), Created: time.Now()})
+	}
+
+	storage.DeleteOne("1")
+
+	if storage.Count() != 24 {
+		t.Errorf("storage.Count() expected: %d, got: %d", 0, storage.Count())
+	}
+}

From a8cd8744e4bae6381e63c175ad3f76e8481d245c Mon Sep 17 00:00:00 2001
From: Andrew Hust <andrew.hust@clickbank.com>
Date: Mon, 14 Nov 2016 19:20:26 -0700
Subject: [PATCH 2/2] switched mutex unlock to be deferred

---
 memory.go | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/memory.go b/memory.go
index 90764d6..9c5be8a 100644
--- a/memory.go
+++ b/memory.go
@@ -25,9 +25,9 @@ func CreateInMemory() *InMemory {
 // Store stores a message and returns its storage ID
 func (memory *InMemory) Store(m *data.Message) (string, error) {
 	memory.mu.Lock()
+	defer memory.mu.Unlock()
 	memory.Messages = append(memory.Messages, m)
 	memory.MessageIDIndex[string(m.ID)] = len(memory.Messages) - 1
-	memory.mu.Unlock()
 	return string(m.ID), nil
 }
 
@@ -161,6 +161,7 @@ func (memory *InMemory) List(start int, limit int) (*data.Messages, error) {
 // DeleteOne deletes an individual message by storage ID
 func (memory *InMemory) DeleteOne(id string) error {
 	memory.mu.Lock()
+	defer memory.mu.Unlock()
 	index := memory.MessageIDIndex[id]
 	delete(memory.MessageIDIndex, id)
 	for k, v := range memory.MessageIDIndex {
@@ -169,16 +170,15 @@ func (memory *InMemory) DeleteOne(id string) error {
 		}
 	}
 	memory.Messages = append(memory.Messages[:index], memory.Messages[index+1:]...)
-	memory.mu.Unlock()
 	return nil
 }
 
 // DeleteAll deletes all in memory messages
 func (memory *InMemory) DeleteAll() error {
 	memory.mu.Lock()
+	defer memory.mu.Unlock()
 	memory.Messages = make([]*data.Message, 0)
 	memory.MessageIDIndex = make(map[string]int)
-	memory.mu.Unlock()
 	return nil
 }