chore: partial done flow

Author: nathanverse

7-lfu-cache/load_group.go

@@ -0,0 +1,71 @@
+package main
+
+import (
+	"container/list"
+	"sync"
+)
+
+type LoadGroup struct {
+	calls map[string]*call
+	mutex sync.Mutex
+	cache *Cache
+}
+
+type call struct {
+	mu     sync.RWMutex
+	result *string
+	err    *error
+}
+
+// Get ensures one loading task is run even if multiple threads are waiting on the same key
+// /*
+func (l *LoadGroup) Get(key string, loaderFunc LoaderFunc) (string, error) {
+	l.mutex.Lock()
+	cache := *(l.cache)
+	vc, err := cache.GetWithoutLoad(key)
+	if err != nil {
+		//
+	}
+
+	if len(vc) != 0 {
+		l.mutex.Unlock()
+		return vc, nil
+	}
+
+	if call, ok := l.calls[key]; ok {
+		l.mutex.Unlock()
+
+		call.mu.RLock()
+		result := call.result
+		call.mu.RUnlock()
+		return *result, nil
+	}
+
+	call := &call{
+		result: new(string),
+	}
+
+	l.calls[key] = call
+	call.mu.Lock()
+	l.mutex.Unlock()
+
+	// TODO: handling panic
+	v, err := loaderFunc(key)
+	if err != nil {
+
+	}
+	call.result = &v
+	call.mu.Unlock()
+
+	// Remove call and update cache
+	l.mutex.Lock()
+	err = cache.Set(key, v)
+	if err != nil {
+		// TODO: handling error
+		l.mutex.Unlock()
+		return "", err
+	}
+
+	delete(l.calls, key)
+	l.mutex.Unlock()
+}

7-lfu-cache/main.go

@@ -10,6 +10,7 @@ var EMPTY_ERROR = errors.New("EMPTY ERROR")
 
 type Cache interface {
 	Get(key string) (string, error)
+	GetWithoutLoad(key string) (string, error)
 	Set(key, value string) error
 }
 
@@ -41,9 +42,6 @@ type lfuItem struct {
 	el    *list.Element // Reference to lruEntry
 }
 
-type LoadGroup struct {
-}
-
 func NewLFUCache(size int, loaderFunc LoaderFunc) (*LFUCache, error) {
 	if size <= 0 {
 		return nil, errors.New("size must be greater than zero")
@@ -99,6 +97,10 @@ func (cache *LFUCache) Get(key string) (string, error) {
 	return value, nil
 }
 
+func load(key string) (string, error) {
+
+}
+
 func (cache *LFUCache) GetKeys() []string {
 	keys := make([]string, 0)
 	for k, _ := range cache.cache {