From 11d4b357743479e0650a5efbaf5536c62f7b576d Mon Sep 17 00:00:00 2001
From: Andrey Ivanov <aivanov@cinimex.ru>
Date: Tue, 23 Jun 2020 14:45:11 +0300
Subject: [PATCH] HW4 is completed

---
 hw04_lru_cache/cache.go      | 26 +++++++++++++++++++-------
 hw04_lru_cache/cache_test.go |  7 +++----
 2 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/hw04_lru_cache/cache.go b/hw04_lru_cache/cache.go
index dd93cfd..1d8288e 100644
--- a/hw04_lru_cache/cache.go
+++ b/hw04_lru_cache/cache.go
@@ -1,4 +1,5 @@
 package hw04_lru_cache //nolint:golint,stylecheck
+import "sync"
 
 type Key string
 
@@ -12,6 +13,7 @@ type lruCache struct {
 	capacity int
 	queue    *List
 	items    map[Key]*ListItem
+	mx       sync.RWMutex
 }
 
 type Item struct {
@@ -23,25 +25,33 @@ func NewCache(capacity int) Cache {
 	return &lruCache{
 		capacity: capacity,
 		queue:    NewList(),
-		items:    map[Key]*ListItem{},
+		items:    make(map[Key]*ListItem),
 	}
 }
 
 func (l *lruCache) Set(key Key, value interface{}) bool {
-	if _, exists := l.Get(key); exists {
-		l.items[key].Value = value
+	if _, exists := l.items[key]; exists {
+		l.mx.RLock()
+		l.items[key].Value = Item{Value: value, Key: key}
+		l.queue.MoveToFront(l.items[key])
+		l.mx.RUnlock()
 		return exists
 	}
-	if l.queue.Len() >= l.capacity {
-		// TODO: нужно как-то удалить элемент из мапа
-		//delete(l.items,l.queue.Back().(*Item).Key)
+	if l.queue.Len() == l.capacity {
+		l.mx.RLock()
+		delete(l.items, l.queue.Back().Value.(Item).Key)
 		l.queue.Remove(l.queue.Back())
+		l.mx.RUnlock()
 	}
-	l.items[key] = l.queue.PushFront(value)
+	l.mx.RLock()
+	l.items[key] = l.queue.PushFront(Item{Value: value, Key: key})
+	l.mx.RUnlock()
 	return false
 }
 
 func (l *lruCache) Get(key Key) (interface{}, bool) {
+	l.mx.Lock()
+	defer l.mx.Unlock()
 	if l.items[key] == nil {
 		return nil, false
 	}
@@ -50,7 +60,9 @@ func (l *lruCache) Get(key Key) (interface{}, bool) {
 }
 
 func (l *lruCache) Clear() {
+	l.mx.Lock()
 	l.items = nil
 	l.queue.len = 0
 	l.queue.Info = ListItem{}
+	l.mx.Unlock()
 }
diff --git a/hw04_lru_cache/cache_test.go b/hw04_lru_cache/cache_test.go
index fd3ea5c..c16cf82 100644
--- a/hw04_lru_cache/cache_test.go
+++ b/hw04_lru_cache/cache_test.go
@@ -31,18 +31,18 @@ func TestCache(t *testing.T) {
 
 		val, ok := c.Get("aaa")
 		require.True(t, ok)
-		require.Equal(t, 100, val)
+		require.Equal(t, 100, val.(Item).Value)
 
 		val, ok = c.Get("bbb")
 		require.True(t, ok)
-		require.Equal(t, 200, val)
+		require.Equal(t, 200, val.(Item).Value)
 
 		wasInCache = c.Set("aaa", 300)
 		require.True(t, wasInCache)
 
 		val, ok = c.Get("aaa")
 		require.True(t, ok)
-		require.Equal(t, 300, val)
+		require.Equal(t, 300, val.(Item).Value)
 
 		val, ok = c.Get("ccc")
 		require.False(t, ok)
@@ -79,7 +79,6 @@ func TestCache(t *testing.T) {
 }
 
 func TestCacheMultithreading(t *testing.T) {
-	t.Skip() // Remove if task with asterisk completed
 
 	c := NewCache(10)
 	wg := &sync.WaitGroup{}