123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123
import { DeferredStack } from "./deferred.ts";import { Connection } from "./connection.ts";import { log } from "./logger.ts";
/** @ignore */export class PoolConnection extends Connection {  _pool?: ConnectionPool = undefined;
  private _idleTimer?: number = undefined;  private _idle = false;
  /**   * Should be called by the pool.   */  enterIdle() {    this._idle = true;    if (this.config.idleTimeout) {      this._idleTimer = setTimeout(() => {        log.info("connection idle timeout");        this._pool!.remove(this);        try {          this.close();        } catch (error) {          log.warning(`error closing idle connection`, error);        }      }, this.config.idleTimeout);    }  }
  /**   * Should be called by the pool.   */  exitIdle() {    this._idle = false;    if (this._idleTimer !== undefined) {      clearTimeout(this._idleTimer);    }  }
  /**   * Remove the connection from the pool permanently, when the connection is not usable.   */  removeFromPool() {    this._pool!.reduceSize();    this._pool = undefined;  }
  returnToPool() {    this._pool?.push(this);  }}
/** @ignore */export class ConnectionPool {  _deferred: DeferredStack<PoolConnection>;  _connections: PoolConnection[] = [];  _closed: boolean = false;
  constructor(maxSize: number, creator: () => Promise<PoolConnection>) {    this._deferred = new DeferredStack(maxSize, this._connections, async () => {      const conn = await creator();      conn._pool = this;      return conn;    });  }
  get info() {    return {      size: this._deferred.size,      maxSize: this._deferred.maxSize,      available: this._deferred.available,    };  }
  push(conn: PoolConnection) {    if (this._closed) {      conn.close();      this.reduceSize();    }    if (this._deferred.push(conn)) {      conn.enterIdle();    }  }
  async pop(): Promise<PoolConnection> {    if (this._closed) {      throw new Error("Connection pool is closed");    }    let conn = this._deferred.tryPopAvailable();    if (conn) {      conn.exitIdle();    } else {      conn = await this._deferred.pop();    }    return conn;  }
  remove(conn: PoolConnection) {    return this._deferred.remove(conn);  }
  /**   * Close the pool and all connections in the pool.   *   * After closing, pop() will throw an error,   * push() will close the connection immediately.   */  close() {    this._closed = true;
    let conn: PoolConnection | undefined;    while (conn = this._deferred.tryPopAvailable()) {      conn.exitIdle();      conn.close();      this.reduceSize();    }  }
  reduceSize() {    this._deferred.reduceSize();  }}