初步实验使用KV数据库（pebble）存储缓存索引

internal/utils/kvstore/table_counter.go

@@ -0,0 +1,33 @@
+// Copyright 2024 GoEdge CDN goedge.cdn@gmail.com. All rights reserved. Official site: https://goedge.cn .
+
+package kvstore
+
+type CounterTable[T int64 | uint64] struct {
+	*Table[T]
+}
+
+func NewCounterTable[T int64 | uint64](name string) (*CounterTable[T], error) {
+	table, err := NewTable[T](name, NewIntValueEncoder[T]())
+	if err != nil {
+		return nil, err
+	}
+
+	return &CounterTable[T]{
+		Table: table,
+	}, nil
+}
+
+func (this *CounterTable[T]) Increase(key string, delta T) (newValue T, err error) {
+	err = this.Table.WriteTx(func(tx *Tx[T]) error {
+		value, getErr := tx.Get(key)
+		if getErr != nil {
+			if !IsKeyNotFound(getErr) {
+				return getErr
+			}
+		}
+
+		newValue = value + delta
+		return tx.Set(key, newValue)
+	})
+	return
+}