/// <reference types="node" />
import { EventEmitter } from "events";
import * as BetterSqlite3 from "better-sqlite3";
export interface PoolConnection extends BetterSqlite3.Database {
    /** Whether the connection is available and can be acquired. */
    readonly available: boolean;
    /** Releases the connection. */
    release(): void;
}
export interface PoolOptions extends BetterSqlite3.Options {
    /**
     * The number of milliseconds to wait when executing queries on a locked
     * database, before throwing a SQLITE_BUSY error. Also, this option is used
     * to determine how long it'd be waited before throwing timeout error when
     * acquiring the connection. (default: 5000).
     */
    timeout?: number;
    /**
     * A function that gets called with every SQL string executed by the
     * database connection (default: `null`).
     */
    verbose?: (...args: any[]) => any;
    /** Max connections in the pool, default is `5`. */
    max?: number;
    onConnectionCreated?: (conn: PoolConnection) => void;
}
export declare class Pool extends EventEmitter implements PoolOptions {
    readonly path: string;
    readonly memory: boolean;
    readonly readonly: boolean;
    readonly fileMustExist: boolean;
    readonly timeout: number;
    readonly verbose: (...args: any[]) => any;
    onConnectionCreated?: (conn: PoolConnection) => void;
    readonly max: number;
    protected connections: PoolConnection[];
    private _closed;
    /**
     * Creates a new pool to store database connections.
     *
     * @param path A SQLite database file path, can be set to
     *  `:memory` to open a memory based database.
     * @param options If this argument is set to a boolean, it's equivalent to
     *  `readonly`, if set to a number, it's equivalent to `max`.
     *
     * @see https://github.com/JoshuaWise/better-sqlite3/wiki/API#new-databasepath-options
     */
    constructor(path: string, options?: number | boolean | PoolOptions);
    /**
     * Acquires a connection from the pool.
     * @see https://github.com/JoshuaWise/better-sqlite3/wiki/API#class-database
     */
    acquire(): Promise<PoolConnection>;
    private _getAvailableConnection;
    private _createConnection;
    /**
     * low level create connection
     * TODO: this should be abstract method for universal Database Pool
     */
    private _rawCreateConnection;
    private _waitConnection;
    /**
     * Closes all connections in the pool.
     * @see https://github.com/JoshuaWise/better-sqlite3/wiki/API#close---this
     */
    close(): void;
}
export default Pool;