import { IDisposable } from "./disposable";
/**
 * The response from a barrier. If the barrier is disposed, the status is "disposed".
 * If the barrier is opened, the status is "resolved" and the value is the value passed to open().
 * This is used instead of rejecting a barrier promise so that error state is explicitly handled.
 */
export type BarrierResponse<T> = {
    status: "disposed";
} | {
    status: "resolved";
    value: T;
};
/**
 * A barrier that is initially closed and then becomes opened permanently.
 * You can wait for the barrier to open, but you cannot close it again.
 */
export declare class Barrier<T> implements IDisposable {
    protected _isOpen: boolean;
    protected _promise: Promise<BarrierResponse<T>>;
    protected _completePromise: (v: BarrierResponse<T>) => void;
    constructor();
    /**
     * Returns true if the barrier is open, false if it is closed
     * @returns true if the barrier is open, false if it is closed
     */
    isOpen(): boolean;
    /**
     * Opens the barrier. If the barrier is already open, this method does nothing.
     * @param value the value to return when the barrier is opened
     * @returns
     */
    open(value: T): void;
    /**
     *
     * @returns a promise that resolves when the barrier is opened. If the barrier is already open, the promise resolves immediately.
     */
    wait(): Promise<BarrierResponse<T>>;
    /**
     * DO NOT USE THIS METHOD in production code. This is only for tests.
     * This is a convenience method that waits for the barrier to open and then returns the value.
     * If the Barrier is disposed while waiting to open, an error is thrown.
     * @returns the value if the barrier is open, otherwise throws an error
     */
    __waitAndThrowIfDisposed(): Promise<T>;
    /**
     * Disposes the barrier.
     * If there is a promise waiting for the barrier to open, it will be resolved with a status of "disposed".
     */
    dispose(): void;
}
/**
 * Like Barrier, but you can close the barrier again
 */
export declare class ClosableBarrier<T> extends Barrier<T> {
    close(): void;
}