import { AbortOptions, MaybePromise, Semaphore, Startable } from '@mithic/commons';
import { Queue } from '../queue.js';
/** A queue of async tasks. */
export declare class TaskQueue implements Startable {
    private readonly semaphore;
    private readonly queue;
    private paused;
    private _pending;
    private queued;
    constructor(semaphore?: Semaphore, queue?: Queue<RunnableTask>, autoStart?: boolean);
    get started(): boolean;
    /** Returns the total number of unfinished tasks. */
    get size(): number;
    /** Returns the number of running but unfinished tasks. */
    get pending(): number;
    /** Pauses further task processing. Already started tasks will keep running. */
    pause(): void;
    start(): void;
    close(options?: AbortOptions): Promise<void>;
    /** Adds a task to this {@link TaskQueue}. */
    push<T>(task: (options?: AbortOptions) => MaybePromise<T>, options?: TaskOptions): Promise<T>;
    /** Polls and waits for the top queue task to complete. */
    poll(options?: AbortOptions): Promise<void>;
    /** Tries to poll the top queue task and waits for it to complete if not throttled. */
    tryPoll(): Promise<void> | undefined;
    private pollLoop;
    private runOnceThenRelease;
    private runOnce;
}
/** A runnable task with priority in a {@link TaskQueue}. */
export declare class RunnableTask {
    /** The task's runnable function. */
    readonly run: () => Promise<void>;
    /** Priority of this task. Operations with greater priority will be scheduled first. Defaults to 0. */
    readonly priority: number;
    constructor(
    /** The task's runnable function. */
    run: () => Promise<void>, 
    /** Priority of this task. Operations with greater priority will be scheduled first. Defaults to 0. */
    priority?: number);
    /** Returns priority of this task. */
    valueOf(): number;
}
/** Options for a task in a {@link TaskQueue}. */
export interface TaskOptions extends AbortOptions {
    /** Priority of operation. Operations with greater priority will be scheduled first. Defaults to 0. */
    priority?: number;
}
//# sourceMappingURL=task.d.ts.map