v0.0.42

dataext/lruMap.go

@@ -19,40 +19,38 @@ import (
 // There are also a bunch of unit tests to ensure that the cache is always in a consistent state
 //
 
-type LRUData interface{}
-
-type LRUMap struct {
+type LRUMap[TData any] struct {
 	maxsize int
 	lock    sync.Mutex
 
-	cache map[string]*cacheNode
+	cache map[string]*cacheNode[TData]
 
-	lfuHead *cacheNode
-	lfuTail *cacheNode
+	lfuHead *cacheNode[TData]
+	lfuTail *cacheNode[TData]
 }
 
-type cacheNode struct {
+type cacheNode[TData any] struct {
 	key    string
-	data   LRUData
-	parent *cacheNode
-	child  *cacheNode
+	data   TData
+	parent *cacheNode[TData]
+	child  *cacheNode[TData]
 }
 
-func NewLRUMap(size int) *LRUMap {
+func NewLRUMap[TData any](size int) *LRUMap[TData] {
 	if size <= 2 && size != 0 {
 		panic("Size must be > 2  (or 0)")
 	}
 
-	return &LRUMap{
+	return &LRUMap[TData]{
 		maxsize: size,
 		lock:    sync.Mutex{},
-		cache:   make(map[string]*cacheNode, size+1),
+		cache:   make(map[string]*cacheNode[TData], size+1),
 		lfuHead: nil,
 		lfuTail: nil,
 	}
 }
 
-func (c *LRUMap) Put(key string, value LRUData) {
+func (c *LRUMap[TData]) Put(key string, value TData) {
 	if c.maxsize == 0 {
 		return // cache disabled
 	}
@@ -70,7 +68,7 @@ func (c *LRUMap) Put(key string, value LRUData) {
 	}
 
 	// key does not exist: insert into map and add to top of LFU
-	node = &cacheNode{
+	node = &cacheNode[TData]{
 		key:    key,
 		data:   value,
 		parent: nil,
@@ -95,9 +93,9 @@ func (c *LRUMap) Put(key string, value LRUData) {
 	}
 }
 
-func (c *LRUMap) TryGet(key string) (LRUData, bool) {
+func (c *LRUMap[TData]) TryGet(key string) (TData, bool) {
 	if c.maxsize == 0 {
-		return nil, false // cache disabled
+		return *new(TData), false // cache disabled
 	}
 
 	c.lock.Lock()
@@ -105,13 +103,13 @@ func (c *LRUMap) TryGet(key string) (LRUData, bool) {
 
 	val, ok := c.cache[key]
 	if !ok {
-		return nil, false
+		return *new(TData), false
 	}
 	c.moveNodeToTop(val)
 	return val.data, ok
 }
 
-func (c *LRUMap) moveNodeToTop(node *cacheNode) {
+func (c *LRUMap[TData]) moveNodeToTop(node *cacheNode[TData]) {
 	// (only called in critical section !)
 
 	if c.lfuHead == node { // fast case
@@ -144,7 +142,7 @@ func (c *LRUMap) moveNodeToTop(node *cacheNode) {
 	}
 }
 
-func (c *LRUMap) Size() int {
+func (c *LRUMap[TData]) Size() int {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 	return len(c.cache)