Cleanup and optimise the code.

cache.go

@@ -5,22 +5,26 @@ import (
 	"time"
 )
 
+// CacheItem represents an item in the cache
 type CacheItem struct {
 	Value     interface{}
 	ExpiresAt time.Time
 }
 
+// Cache is a simple in-memory cache
 type Cache struct {
 	items map[string]CacheItem
 	mutex sync.RWMutex
 }
 
+// NewCache creates a new Cache
 func NewCache() *Cache {
 	return &Cache{
 		items: make(map[string]CacheItem),
 	}
 }
 
+// Set adds an item to the cache
 func (c *Cache) Set(key string, value interface{}, expiration time.Duration) {
 	c.mutex.Lock()
 	defer c.mutex.Unlock()
@@ -30,6 +34,7 @@ func (c *Cache) Set(key string, value interface{}, expiration time.Duration) {
 	}
 }
 
+// Get retrieves an item from the cache
 func (c *Cache) Get(key string) (interface{}, bool) {
 	c.mutex.RLock()
 	defer c.mutex.RUnlock()
@@ -44,12 +49,14 @@ func (c *Cache) Get(key string) (interface{}, bool) {
 	return item.Value, true
 }
 
+// Delete removes an item from the cache
 func (c *Cache) Delete(key string) {
 	c.mutex.Lock()
 	defer c.mutex.Unlock()
 	delete(c.items, key)
 }
 
+// Cleanup removes expired items from the cache
 func (c *Cache) Cleanup() {
 	c.mutex.Lock()
 	defer c.mutex.Unlock()