From 0da04c6f172052583c54e152e98c85e585f01d41 Mon Sep 17 00:00:00 2001
From: "Frederick F. Kautz IV" <fkautz@alumni.cmu.edu>
Date: Wed, 29 Apr 2015 15:28:42 -0700
Subject: [PATCH] Expirations are now based on last accessed instead of time
 created

---
 pkg/server/server.go                  |  2 +-
 pkg/storage/drivers/memory/lru/lru.go | 15 +++++++++++++++
 pkg/storage/drivers/memory/memory.go  | 11 +++++++++++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/pkg/server/server.go b/pkg/server/server.go
index 4d3338775..479441038 100644
--- a/pkg/server/server.go
+++ b/pkg/server/server.go
@@ -39,7 +39,7 @@ type MemoryFactory struct {
 // GetStartServerFunc builds memory api servers
 func (f MemoryFactory) GetStartServerFunc() StartServerFunc {
 	return func() (chan<- string, <-chan error) {
-		_, _, driver := memory.Start(f.MaxMemory, 3*time.Hour)
+		_, _, driver := memory.Start(f.MaxMemory, 1*time.Hour)
 		ctrl, status, _ := httpserver.Start(api.HTTPHandler(f.Domain, driver), f.Config)
 		return ctrl, status
 	}
diff --git a/pkg/storage/drivers/memory/lru/lru.go b/pkg/storage/drivers/memory/lru/lru.go
index e0c34a024..4dabcf72b 100644
--- a/pkg/storage/drivers/memory/lru/lru.go
+++ b/pkg/storage/drivers/memory/lru/lru.go
@@ -34,6 +34,7 @@ package lru
 
 import (
 	"container/list"
+	"sync"
 )
 
 // Cache is an LRU cache. It is not safe for concurrent access.
@@ -48,6 +49,7 @@ type Cache struct {
 
 	ll    *list.List
 	cache map[interface{}]*list.Element
+	lock  *sync.RWMutex
 }
 
 // A Key may be any value that is comparable. See http://golang.org/ref/spec#Comparison_operators
@@ -66,11 +68,14 @@ func New(maxEntries int) *Cache {
 		MaxEntries: maxEntries,
 		ll:         list.New(),
 		cache:      make(map[interface{}]*list.Element),
+		lock:       &sync.RWMutex{},
 	}
 }
 
 // Add adds a value to the cache.
 func (c *Cache) Add(key Key, value interface{}) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
 	if c.cache == nil {
 		c.cache = make(map[interface{}]*list.Element)
 		c.ll = list.New()
@@ -89,6 +94,8 @@ func (c *Cache) Add(key Key, value interface{}) {
 
 // Get looks up a key's value from the cache.
 func (c *Cache) Get(key Key) (value interface{}, ok bool) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
 	if c.cache == nil {
 		return
 	}
@@ -101,6 +108,8 @@ func (c *Cache) Get(key Key) (value interface{}, ok bool) {
 
 // Remove removes the provided key from the cache.
 func (c *Cache) Remove(key Key) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
 	if c.cache == nil {
 		return
 	}
@@ -111,6 +120,8 @@ func (c *Cache) Remove(key Key) {
 
 // RemoveOldest removes the oldest item from the cache.
 func (c *Cache) RemoveOldest() {
+	c.lock.Lock()
+	defer c.lock.Unlock()
 	if c.cache == nil {
 		return
 	}
@@ -122,6 +133,8 @@ func (c *Cache) RemoveOldest() {
 
 // GetOldest returns the oldest key, value, ok without modifying the lru
 func (c *Cache) GetOldest() (key Key, value interface{}, ok bool) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
 	if c.cache == nil {
 		return nil, nil, false
 	}
@@ -143,6 +156,8 @@ func (c *Cache) removeElement(e *list.Element) {
 
 // Len returns the number of items in the cache.
 func (c *Cache) Len() int {
+	c.lock.Lock()
+	defer c.lock.Unlock()
 	if c.cache == nil {
 		return 0
 	}
diff --git a/pkg/storage/drivers/memory/memory.go b/pkg/storage/drivers/memory/memory.go
index 26c19d342..56c299275 100644
--- a/pkg/storage/drivers/memory/memory.go
+++ b/pkg/storage/drivers/memory/memory.go
@@ -123,6 +123,7 @@ func (memory *memoryDriver) GetObject(w io.Writer, bucket string, object string)
 			dataSlice := data.([]byte)
 			objectBuffer := bytes.NewBuffer(dataSlice)
 			written, err := io.Copy(w, objectBuffer)
+			go memory.updateAccessTime(objectKey)
 			return written, iodine.New(err, nil)
 		}
 	}
@@ -282,6 +283,7 @@ func (memory *memoryDriver) CreateObject(bucket, key, contentType, expectedMD5Su
 		Md5:         md5Sum,
 		Size:        int64(totalLength),
 	}
+	newObject.lastAccessed = time.Now()
 	memory.lock.Lock()
 	if _, ok := memory.objectMetadata[objectKey]; ok == true {
 		memory.lock.Unlock()
@@ -503,3 +505,12 @@ func (memory *memoryDriver) expireObjects() {
 		}
 	}
 }
+
+func (memory *memoryDriver) updateAccessTime(key string) {
+	memory.lock.Lock()
+	defer memory.lock.Unlock()
+	if object, ok := memory.objectMetadata[key]; ok {
+		object.lastAccessed = time.Now()
+		memory.objectMetadata[key] = object
+	}
+}