fix: paginate messages for maildir storage

Fixes mailhog/MailHog#178

Author: dsalahutdinov

maildir.go

@@ -134,12 +134,14 @@ func (maildir *Maildir) List(start, limit int) (*data.Messages, error) {
 	}
 	defer dir.Close()
 
-	n, err := dir.Readdir(0)
+	files, err := dir.Readdir(0)
 	if err != nil {
 		return nil, err
 	}
+	from := minInt(start, len(files)-1)
+	to := minInt(start+limit, len(files)-1)
 
-	for _, fileinfo := range n {
+	for _, fileinfo := range files[from:to] {
 		b, err := ioutil.ReadFile(filepath.Join(maildir.Path, fileinfo.Name()))
 		if err != nil {
 			return nil, err
@@ -182,3 +184,10 @@ func (maildir *Maildir) Load(id string) (*data.Message, error) {
 	m.ID = data.MessageID(id)
 	return m, nil
 }
+
+func minInt(x, y int) int {
+	if x < y {
+		return x
+	}
+	return y
+}

maildir_test.go

@@ -0,0 +1,59 @@
+package storage
+
+import (
+	"testing"
+)
+
+func TestMaildirStore(t *testing.T) {
+	storage := CreateMaildir("testdata")
+
+	if storage.Count() != 0 {
+		t.Errorf("storage.Count() expected: %d, got: %d", 0, storage.Count())
+	}
+
+	fillStorage(storage, 25)
+
+	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 TestMaildirLoad(t *testing.T) {
+	storage := CreateMaildir("testdata")
+
+	storage.Store(newMessage("123"))
+
+	item, err := storage.Load("123")
+	if item == nil || err != nil {
+		t.Errorf("storage.Load(\"123\") expected: not nil, got: nil")
+	}
+
+	unexisting, err := storage.Load("321")
+	if unexisting != nil || err == nil {
+		t.Errorf("storage.Load(\"321\") expected: nil, got: not nil")
+	}
+	storage.DeleteAll()
+}
+
+func TestMaildirList(t *testing.T) {
+	storage := CreateMaildir("testdata")
+
+	fillStorage(storage, 25)
+
+	result, err := storage.List(0, 10)
+	if len(*result) != 10 || err != nil {
+		t.Errorf("len(result) expected: %d, got: %d", 10, len(*result))
+	}
+
+	result, err = storage.List(20, 30)
+	if len(*result) != 5 || err != nil {
+		t.Errorf("len(result) expected: %d, got: %d", 5, len(*result))
+	}
+	storage.DeleteAll()
+}

memory_test.go

@@ -9,7 +9,7 @@ import (
 	"github.com/mailhog/data"
 )
 
-func TestStore(t *testing.T) {
+func TestImMemoryStore(t *testing.T) {
 	storage := CreateInMemory()
 
 	if storage.Count() != 0 {
@@ -35,7 +35,7 @@ func TestStore(t *testing.T) {
 	}
 }
 
-func TestDeleteAll(t *testing.T) {
+func TestImMemoryDeleteAll(t *testing.T) {
 	storage := CreateInMemory()
 
 	if storage.Count() != 0 {
@@ -57,7 +57,7 @@ func TestDeleteAll(t *testing.T) {
 	}
 }
 
-func TestDeleteOne(t *testing.T) {
+func TestImMemoryDeleteOne(t *testing.T) {
 	storage := CreateInMemory()
 
 	if storage.Count() != 0 {

storage_test.go

@@ -0,0 +1,35 @@
+package storage
+
+import (
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/mailhog/data"
+)
+
+func fillStorage(storage Storage, itemsCount int) {
+	var wg sync.WaitGroup
+	wg.Add(itemsCount)
+	for i := 0; i < itemsCount; i++ {
+		go func(i int) {
+			msg := newMessage(strconv.Itoa(i))
+			storage.Store(msg)
+			wg.Done()
+		}(i)
+	}
+	wg.Wait()
+}
+
+func newMessage(messageID string) *data.Message {
+	return &data.Message{
+		ID:      data.MessageID(messageID),
+		Created: time.Now(),
+		Raw: &data.SMTPMessage{
+			From: "from@email.com",
+			To:   []string{"to@email.com"},
+			Data: "some data string",
+			Helo: "helo string",
+		},
+	}
+}