import type { dh } from '@deephaven/jsapi-types';
import { type UriVariableDescriptor } from './useObjectFetcher';
/** Function for unsubscribing from a given subscription */
export type UnsubscribeFunction = () => void;
/** Update when the ObjectFetch is still loading */
export type ObjectFetchLoading = {
    status: 'loading';
};
/** Update when the ObjectFetch has errored */
export type ObjectFetchError = {
    error: NonNullable<unknown>;
    status: 'error';
};
/** Update when the object is ready */
export type ObjectFetchReady<T> = {
    fetch: () => Promise<T>;
    status: 'ready';
};
/**
 * Update with the current `fetch` function and status of the object.
 * - If both `fetch` and `error` are `null`, it is still loading the fetcher
 * - If `fetch` is not `null`, the object is ready to be fetched
 * - If `error` is not `null`, there was an error loading the object
 */
export type ObjectFetchUpdate<T = unknown> = ObjectFetchLoading | ObjectFetchError | ObjectFetchReady<T>;
export type ObjectFetchUpdateCallback<T = unknown> = (update: ObjectFetchUpdate<T>) => void;
/** ObjectFetchManager for managing a subscription to an object using a VariableDescriptor */
export type ObjectFetchManager = {
    /**
     * Subscribe to the fetch function for an object using a variable descriptor.
     * It's possible that the fetch function changes over time, due to disconnection/reconnection, starting/stopping of applications that the object may be associated with, etc.
     *
     * @param descriptor Descriptor object or URI of the object to fetch. Can be extended by a specific implementation to include more details necessary for the ObjectManager.
     * @param onUpdate Callback function to be called when the object is updated.
     * @returns An unsubscribe function to stop listening for fetch updates and clean up the object.
     */
    subscribe: <T = unknown>(descriptor: dh.ide.VariableDescriptor | UriVariableDescriptor, onUpdate: ObjectFetchUpdateCallback<T>) => UnsubscribeFunction;
};
/** Context for tracking an implementation of the ObjectFetchManager. */
export declare const ObjectFetchManagerContext: import("react").Context<ObjectFetchManager | null>;
/**
 * Retrieve a `fetch` function for the given variable descriptor.
 *
 * @param descriptor Descriptor or URI to get the `fetch` function for
 * @returns An object with the current `fetch` function, OR an error status set if there was an issue fetching the object.
 *          Retrying is left up to the ObjectManager implementation used from this context.
 */
export declare function useObjectFetch<T = unknown>(descriptor: dh.ide.VariableDescriptor | UriVariableDescriptor): ObjectFetchUpdate<T>;
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