From 1f2e80cd3953a8e0d39aed9cd3ce3916800764ea Mon Sep 17 00:00:00 2001
From: po-lan <42771836+po-lan@users.noreply.github.com>
Date: Mon, 27 May 2024 17:05:28 +0800
Subject: [PATCH] =?UTF-8?q?=E5=AF=B9=20get=5Fgroup=5Fmember=5Flist=20?=
 =?UTF-8?q?=E5=A2=9E=E5=BC=BA?=
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一个基于LRU思想写出来的缓存结构
来降低写入数据库的次数
---
 src/onebot11/action/group/LRUCache.ts | 178 ++++++++++++++++++++++++++
 1 file changed, 178 insertions(+)
 create mode 100644 src/onebot11/action/group/LRUCache.ts

diff --git a/src/onebot11/action/group/LRUCache.ts b/src/onebot11/action/group/LRUCache.ts
new file mode 100644
index 00000000..d45bf8ba
--- /dev/null
+++ b/src/onebot11/action/group/LRUCache.ts
@@ -0,0 +1,178 @@
+import { logError, logDebug } from "@/common/utils/log";
+
+type group_id = number;
+type user_id = number;
+
+class cacheNode<T> {
+  value: T;
+  groupId: group_id;
+  userId: user_id;
+  prev: cacheNode<T> | null;
+  next: cacheNode<T> | null;
+  timestamp: number;
+
+  constructor(groupId: group_id, userId: user_id, value: T) {
+    this.groupId = groupId;
+    this.userId = userId;
+    this.value = value;
+    this.prev = null;
+    this.next = null;
+    this.timestamp = Date.now();
+  }
+}
+
+type cache<T> = { [key: group_id]: { [key: user_id]: cacheNode<T> } };
+class LRU<T> {
+  private maxAge: number;
+  private maxSize: number;
+  private currentSize: number;
+  private cache: cache<T>;
+  private head: cacheNode<T> | null = null;
+  private tail: cacheNode<T> | null = null;
+  private onFuncs: ((node: cacheNode<T>) => void)[] = [];
+
+  constructor(maxAge: number = 2e4, maxSize: number = 5e3) {
+    this.maxAge = maxAge;
+    this.maxSize = maxSize;
+    this.cache = Object.create(null);
+    this.currentSize = 0;
+
+    if (maxSize == 0) return;
+    setInterval(() => this.removeExpired(), this.maxAge);
+  }
+
+  // 移除LRU节点
+  private removeLRUNode(node: cacheNode<T>) {
+    logDebug(
+      "removeLRUNode",
+      node.groupId,
+      node.userId,
+      node.value,
+      this.currentSize
+    );
+    node.prev = node.next = null;
+    delete this.cache[node.groupId][node.userId];
+    this.removeNode(node);
+    this.onFuncs.forEach((func) => func(node));
+    this.currentSize--;
+    logDebug("removeLRUNode", "After", this.currentSize);
+  }
+
+  public on(func: (node: cacheNode<T>) => void) {
+    this.onFuncs.push(func);
+  }
+
+  private removeExpired() {
+    console.log("remove expired LRU node", !!this.tail);
+    //console.log(`now current`, this.currentSize);
+    //const rCurrent = Object.values(this.cache)
+    //  .map((group) => Object.values(group))
+    //  .flat().length;
+    //console.log(`realiy current`, rCurrent);
+
+    const now = Date.now();
+    let current = this.tail;
+    const nodesToRemove: cacheNode<T>[] = [];
+    let removedCount = 0;
+
+    // 收集需要删除的节点
+    while (current && now - current.timestamp > this.maxAge) {
+      nodesToRemove.push(current);
+      current = current.prev;
+      removedCount++;
+      if (removedCount >= 100) break;
+    }
+
+    // 更新链表指向
+    if (nodesToRemove.length > 0) {
+      const newTail = nodesToRemove[nodesToRemove.length - 1].prev;
+      if (newTail) {
+        newTail.next = null;
+      } else {
+        this.head = null;
+      }
+      this.tail = newTail;
+    }
+
+    // 删除收集到的节点
+    // console.log(nodesToRemove)
+    nodesToRemove.forEach((node) => {
+      // console.log("node is null", node === null);
+      node.prev = node.next = null;
+      delete this.cache[node.groupId][node.userId];
+
+      this.currentSize--;
+      this.onFuncs.forEach((func) => func(node));
+    });
+    
+    console.log("after remove expired current", this.currentSize);
+    // console.log(
+    //  "after remove expired realiy current",
+    //  Object.values(this.cache)
+    //    .map((group) => Object.values(group))
+    //    .flat().length
+    // );
+  }
+
+  private addNode(node: cacheNode<T>) {
+    node.next = this.head;
+    if (this.head) this.head.prev = node;
+    if (!this.tail) this.tail = node;
+    this.head = node;
+  }
+
+  private removeNode(node: cacheNode<T>) {
+    if (node.prev) node.prev.next = node.next;
+    if (node.next) node.next.prev = node.prev;
+    if (node === this.head) this.head = node.next;
+    if (node === this.tail) this.tail = node.prev;
+  }
+
+  private moveToHead(node: cacheNode<T>) {
+    if (this.head === node) return;
+
+    this.removeNode(node);
+    this.addNode(node);
+    node.prev = null;
+
+    logDebug("moveToHead", node.groupId, node.userId, node.value);
+  }
+
+  public set(groupId: group_id, userId: user_id, value: T) {
+    logDebug("set", groupId, userId, value, this.currentSize);
+
+    if (!this.cache[groupId]) {
+      logDebug("set", "create group", groupId);
+      this.cache[groupId] = Object.create(null);
+    }
+
+    const groupObject = this.cache[groupId];
+
+    if (groupObject[userId]) {
+      logDebug("update", groupId, userId, value);
+      const node = groupObject[userId];
+      node.value = value;
+      node.timestamp = Date.now();
+      this.moveToHead(node);
+    } else {
+      logDebug("add", groupId, userId, value);
+      const node = new cacheNode(groupId, userId, value);
+      groupObject[userId] = node;
+      this.currentSize++;
+      this.addNode(node);
+      if (this.currentSize > this.maxSize) {
+        const tail = this.tail!;
+        logDebug(
+          "remove expired LRU node",
+          tail.groupId,
+          tail.userId,
+          tail.value,
+          this.currentSize
+        );
+        this.removeLRUNode(tail);
+      }
+    }
+  }
+}
+
+export default LRU;