Исходники и презентации

lessons/garbage_collector/weak_map/main.go

@@ -0,0 +1,48 @@
+package main
+
+import (
+	"runtime"
+	"time"
+	"weak"
+)
+
+type WeakMap struct {
+	data map[string]weak.Pointer[string]
+}
+
+func NewWeakMap() WeakMap {
+	return WeakMap{
+		data: make(map[string]weak.Pointer[string]),
+	}
+}
+
+func (w *WeakMap) Set(key string, value *string) {
+	runtime.AddCleanup(value, w.Delete, key)
+	w.data[key] = weak.Make(value)
+}
+
+func (w *WeakMap) Get(key string) *string {
+	if ptr, ok := w.data[key]; ok {
+		return ptr.Value()
+	}
+
+	return nil
+}
+
+func (w *WeakMap) Delete(key string) {
+	delete(w.data, key)
+}
+
+func main() {
+	data := NewWeakMap()
+
+	key := "my key"
+	value := "my data"
+	data.Set(key, &value)
+
+	runtime.GC()
+	time.Sleep(time.Second)
+
+	pointer := data.Get(key)
+	println(pointer == nil)
+}