Avoid one last memory copy

pkg/api/api_router.go

@@ -63,7 +63,7 @@ func HTTPHandler(driver drivers.Driver) http.Handler {
 	//	h = quota.BandwidthCap(h, 100*1024*1024, time.Duration(24*time.Hour))
 	//	h = quota.RequestLimit(h, 100, time.Duration(30*time.Minute))
 	//	h = quota.RequestLimit(h, 1000, time.Duration(24*time.Hour))
-	h = quota.ConnectionLimit(h, 5)
+	h = quota.ConnectionLimit(h, 4)
 	h = logging.LogHandler(h)
 	return h
 }

pkg/storage/drivers/memory/memory.go

@@ -43,7 +43,7 @@ import (
 type memoryDriver struct {
 	storedBuckets map[string]storedBucket
 	lock          *sync.RWMutex
-	objects       *Intelligent
+	objects       *Cache
 }
 
 type storedBucket struct {
@@ -69,7 +69,7 @@ func Start(maxSize uint64, expiration time.Duration) (chan<- string, <-chan erro
 	var memory *memoryDriver
 	memory = new(memoryDriver)
 	memory.storedBuckets = make(map[string]storedBucket)
-	memory.objects = NewIntelligent(maxSize, expiration)
+	memory.objects = NewCache(maxSize, expiration)
 	memory.lock = new(sync.RWMutex)
 
 	memory.objects.OnExpired = memory.expiredObject
@@ -207,30 +207,6 @@ func (memory *memoryDriver) CreateObject(bucket, key, contentType, expectedMD5Su
 	return md5sum, iodine.New(err, nil)
 }
 
-// getMD5AndData - this is written as a wrapper to capture md5sum and data in a more memory efficient way
-func getMD5AndData(reader io.Reader) ([]byte, []byte, error) {
-	hash := md5.New()
-	var data []byte
-
-	var err error
-	var length int
-	for err == nil {
-		byteBuffer := make([]byte, 1024*1024)
-		length, err = reader.Read(byteBuffer)
-		// While hash.Write() wouldn't mind a Nil byteBuffer
-		// It is necessary for us to verify this and break
-		if length == 0 {
-			break
-		}
-		hash.Write(byteBuffer[0:length])
-		data = append(data, byteBuffer[0:length]...)
-	}
-	if err != io.EOF {
-		return nil, nil, err
-	}
-	return hash.Sum(nil), data, nil
-}
-
 // createObject - PUT object to memory buffer
 func (memory *memoryDriver) createObject(bucket, key, contentType, expectedMD5Sum string, size int64, data io.Reader) (string, error) {
 	memory.lock.RLock()
@@ -267,15 +243,35 @@ func (memory *memoryDriver) createObject(bucket, key, contentType, expectedMD5Su
 		}
 		expectedMD5Sum = hex.EncodeToString(expectedMD5SumBytes)
 	}
-	md5SumBytes, readBytes, err := getMD5AndData(data)
+
-	if err != nil {
+	// calculate md5
+	hash := md5.New()
+	var readBytes []byte
+
+	var err error
+	var length int
+	for err == nil {
+		byteBuffer := make([]byte, 1024*1024)
+		length, err = data.Read(byteBuffer)
+		// While hash.Write() wouldn't mind a Nil byteBuffer
+		// It is necessary for us to verify this and break
+		if length == 0 {
+			break
+		}
+		hash.Write(byteBuffer[0:length])
+		readBytes = append(readBytes, byteBuffer[0:length]...)
+	}
+	if err != io.EOF {
 		return "", iodine.New(err, nil)
 	}
+	go debug.FreeOSMemory()
+	md5SumBytes := hash.Sum(nil)
 	totalLength := len(readBytes)
+
 	memory.lock.Lock()
 	memory.objects.Set(objectKey, readBytes)
 	memory.lock.Unlock()
-	// de-allocating
+	// setting up for de-allocation
 	readBytes = nil
 
 	md5Sum := hex.EncodeToString(md5SumBytes)

pkg/storage/drivers/memory/memory_cache.go

@@ -23,9 +23,9 @@ import (
 
 var zeroExpiration = time.Duration(0)
 
-// Intelligent holds the required variables to compose an in memory cache system
+// Cache holds the required variables to compose an in memory cache system
 // which also provides expiring key mechanism and also maxSize
-type Intelligent struct {
+type Cache struct {
 	// Mutex is used for handling the concurrent
 	// read/write requests for cache
 	sync.Mutex
@@ -62,12 +62,12 @@ type Stats struct {
 	Expired uint64
 }
 
-// NewIntelligent creates an inmemory cache
+// NewCache creates an inmemory cache
 //
 // maxSize is used for expiring objects before we run out of memory
 // expiration is used for expiration of a key from cache
-func NewIntelligent(maxSize uint64, expiration time.Duration) *Intelligent {
+func NewCache(maxSize uint64, expiration time.Duration) *Cache {
-	return &Intelligent{
+	return &Cache{
 		items:      map[string]interface{}{},
 		updatedAt:  map[string]time.Time{},
 		expiration: expiration,
@@ -76,7 +76,7 @@ func NewIntelligent(maxSize uint64, expiration time.Duration) *Intelligent {
 }
 
 // Stats get current cache statistics
-func (r *Intelligent) Stats() Stats {
+func (r *Cache) Stats() Stats {
 	return Stats{
 		Bytes:   r.currentSize,
 		Items:   uint64(len(r.items)),
@@ -85,7 +85,7 @@ func (r *Intelligent) Stats() Stats {
 }
 
 // ExpireObjects expire objects in go routine
-func (r *Intelligent) ExpireObjects(gcInterval time.Duration) {
+func (r *Cache) ExpireObjects(gcInterval time.Duration) {
 	r.stopExpireTimer = make(chan struct{})
 	ticker := time.NewTicker(gcInterval)
 	go func() {
@@ -103,7 +103,7 @@ func (r *Intelligent) ExpireObjects(gcInterval time.Duration) {
 }
 
 // Get returns a value of a given key if it exists
-func (r *Intelligent) Get(key string) (interface{}, bool) {
+func (r *Cache) Get(key string) (interface{}, bool) {
 	r.Lock()
 	defer r.Unlock()
 	value, ok := r.items[key]
@@ -115,7 +115,7 @@ func (r *Intelligent) Get(key string) (interface{}, bool) {
 }
 
 // Set will persist a value to the cache
-func (r *Intelligent) Set(key string, value interface{}) {
+func (r *Cache) Set(key string, value interface{}) {
 	r.Lock()
 	// remove random key if only we reach the maxSize threshold,
 	// if not assume infinite memory
@@ -135,7 +135,7 @@ func (r *Intelligent) Set(key string, value interface{}) {
 }
 
 // Expire expires keys which have expired
-func (r *Intelligent) Expire() {
+func (r *Cache) Expire() {
 	r.Lock()
 	defer r.Unlock()
 	for key := range r.items {
@@ -146,7 +146,7 @@ func (r *Intelligent) Expire() {
 }
 
 // Delete deletes a given key if exists
-func (r *Intelligent) Delete(key string) {
+func (r *Cache) Delete(key string) {
 	if _, ok := r.items[key]; ok {
 		r.currentSize -= uint64(len(r.items[key].([]byte)))
 		delete(r.items, key)
@@ -158,7 +158,7 @@ func (r *Intelligent) Delete(key string) {
 	}
 }
 
-func (r *Intelligent) isValid(key string) bool {
+func (r *Cache) isValid(key string) bool {
 	updatedAt, ok := r.updatedAt[key]
 	if !ok {
 		return false