add a concurrent-safe map

tools/rwmap/rwmap.go

@@ -0,0 +1,59 @@
+package rwmap
+
+import (
+	"sync"
+)
+
+type RWMap[K comparable, V any] struct {
+	m map[K]V
+	sync.RWMutex
+}
+
+func NewRWMap[K comparable, V any]() *RWMap[K, V] {
+	return &RWMap[K, V]{
+		m: make(map[K]V),
+	}
+}
+
+func (rw *RWMap[K, V]) Get(key K) (V, bool) {
+	rw.RLock()
+	value, ok := rw.m[key]
+	rw.RUnlock()
+	return value, ok
+}
+
+func (rw *RWMap[K, V]) Set(key K, value V) {
+	rw.Lock()
+	rw.m[key] = value
+	rw.Unlock()
+}
+
+func (rw *RWMap[K, V]) Delete(key K) {
+	rw.Lock()
+	delete(rw.m, key)
+	rw.Unlock()
+}
+
+func (rw *RWMap[K, V]) Exists(key K) bool {
+	rw.RLock()
+	_, exists := rw.m[key]
+	rw.RUnlock()
+	return exists
+}
+
+func (rw *RWMap[K, V]) Len() int {
+	rw.RLock()
+	length := len(rw.m)
+	rw.RUnlock()
+	return length
+}
+
+func (rw *RWMap[K, V]) Iterate(iter func(K, V) bool) {
+	rw.RLock()
+	defer rw.RUnlock()
+	for k, v := range rw.m {
+		if !iter(k, v) {
+			break
+		}
+	}
+}