refactor: rewrite task pool

src/libs/pool.js

@@ -3,74 +3,132 @@ import { kissLog } from "./log";
 
 /**
  * 任务池
- * @param {*} _interval
- * @param {*} _limit
- * @param {*} _retryInteral
- * @returns
  */
-const TaskPool = (_interval = 100, _limit = 100, _retryInteral = 1000) => {
-  const pool = [];
-  const maxRetry = 2; // 最大重试次数
-  let maxCount = _limit; // 最大数量
-  let curCount = 0; // 当前数量
-  let interval = _interval; // 间隔时间
-  let timer = null;
+class TaskPool {
+  #pool = [];
 
-  const run = async () => {
-    // console.log("timer", timer);
-    timer && clearTimeout(timer);
-    timer = setTimeout(run, interval);
+  #maxRetry = 2; // 最大重试次数
+  #retryInterval = 1000; // 重试间隔时间
+  #limit; // 最大并发数
+  #interval; // 任务最小启动间隔
 
-    if (curCount < maxCount) {
-      const item = pool.shift();
-      if (item) {
-        curCount++;
-        const { fn, args, resolve, reject, retry } = item;
-        try {
-          const res = await fn(args);
-          resolve(res);
-        } catch (err) {
-          kissLog(err, "task");
-          if (retry < maxRetry) {
-            const retryTimer = setTimeout(() => {
-              clearTimeout(retryTimer);
-              pool.push({ fn, args, resolve, reject, retry: retry + 1 });
-            }, _retryInteral);
-          } else {
-            reject(err);
-          }
-        } finally {
-          curCount--;
+  #currentConcurrent = 0; // 当前正在执行的任务数
+  #lastExecutionTime = 0; // 上一个任务的启动时间
+  #schedulerTimer = null; // 用于调度下一个任务的定时器
+
+  constructor(
+    interval = DEFAULT_FETCH_INTERVAL,
+    limit = DEFAULT_FETCH_LIMIT,
+    retryInterval = 1000
+  ) {
+    this.#interval = interval;
+    this.#limit = limit;
+    this.#retryInterval = retryInterval;
+  }
+
+  /**
+   * 调度器
+   */
+  #scheduleNext() {
+    if (this.#schedulerTimer) {
+      return;
+    }
+
+    if (this.#currentConcurrent >= this.#limit || this.#pool.length === 0) {
+      return;
+    }
+
+    const now = Date.now();
+    const timeSinceLast = now - this.#lastExecutionTime;
+    const delay = Math.max(0, this.#interval - timeSinceLast);
+
+    this.#schedulerTimer = setTimeout(() => {
+      this.#schedulerTimer = null;
+      if (this.#currentConcurrent < this.#limit && this.#pool.length > 0) {
+        const task = this.#pool.shift();
+        if (task) {
+          this.#lastExecutionTime = Date.now();
+          this.#execute(task);
         }
       }
-    }
-  };
 
-  return {
-    push: async (fn, args) => {
-      if (!timer) {
-        run();
+      if (this.#pool.length > 0) {
+        this.#scheduleNext();
       }
-      return new Promise((resolve, reject) => {
-        pool.push({ fn, args, resolve, reject, retry: 0 });
-      });
-    },
-    update: (_interval = 100, _limit = 100) => {
-      if (_interval >= 0 && _interval <= 5000 && _interval !== interval) {
-        interval = _interval;
+    }, delay);
+  }
+
+  /**
+   * 执行单个任务
+   * @param {object} task - 任务对象
+   */
+  async #execute(task) {
+    this.#currentConcurrent++;
+    const { fn, args, resolve, reject, retry } = task;
+
+    try {
+      const res = await fn(args);
+      resolve(res);
+    } catch (err) {
+      kissLog(err, "task");
+      if (retry < this.#maxRetry) {
+        setTimeout(() => {
+          this.#pool.unshift({ ...task, retry: retry + 1 }); // unshift 保证重试任务优先
+          this.#scheduleNext();
+        }, this.#retryInterval);
+      } else {
+        reject(err);
       }
-      if (_limit >= 1 && _limit <= 100 && _limit !== maxCount) {
-        maxCount = _limit;
-      }
-    },
-    clear: () => {
-      pool.length = 0;
-      curCount = 0;
-      timer && clearTimeout(timer);
-      timer = null;
-    },
-  };
-};
+    } finally {
+      this.#currentConcurrent--;
+      this.#scheduleNext();
+    }
+  }
+
+  /**
+   * 向任务池中添加一个新任务
+   * @param {Function} fn - 要执行的异步函数
+   * @param {*} args - 函数的参数
+   * @returns {Promise}
+   */
+  push(fn, args) {
+    return new Promise((resolve, reject) => {
+      this.#pool.push({ fn, args, resolve, reject, retry: 0 });
+      this.#scheduleNext();
+    });
+  }
+
+  /**
+   * 更新任务池的配置
+   * @param {number} interval - 新的最小任务间隔
+   * @param {number} limit - 新的最大并发数
+   */
+  update(interval, limit) {
+    if (interval >= 0) {
+      this.#interval = interval;
+    }
+    if (limit >= 1) {
+      this.#limit = limit;
+    }
+
+    this.#scheduleNext();
+  }
+
+  /**
+   * 清空任务池
+   */
+  clear() {
+    for (const task of this.#pool) {
+      task.reject("the task pool was cleared");
+    }
+
+    this.#pool.length = 0;
+    if (this.#schedulerTimer) {
+      clearTimeout(this.#schedulerTimer);
+      this.#schedulerTimer = null;
+    }
+  }
+}
 
 /**
  * 请求池实例
@@ -79,20 +137,19 @@ let fetchPool;
 
 /**
  * 获取请求池实例
- * @param {*} interval
- * @param {*} limit
+ * @param interval
+ * @param limit
  * @returns
  */
 export const getFetchPool = (interval, limit) => {
   if (!fetchPool) {
-    fetchPool = TaskPool(
+    fetchPool = new TaskPool(
       interval ?? DEFAULT_FETCH_INTERVAL,
       limit ?? DEFAULT_FETCH_LIMIT
     );
   } else if (interval && limit) {
     updateFetchPool(interval, limit);
   }
-
   return fetchPool;
 };
 
@@ -102,12 +159,12 @@ export const getFetchPool = (interval, limit) => {
  * @param {*} limit
  */
 export const updateFetchPool = (interval, limit) => {
-  fetchPool && fetchPool.update(interval, limit);
+  fetchPool?.update(interval, limit);
 };
 
 /**
  * 清空请求池
  */
 export const clearFetchPool = () => {
-  fetchPool && fetchPool.clear();
+  fetchPool?.clear();
 };