/// <reference types="node" />
/// <reference types="node" />
import { Readable } from 'stream';
import type { Document, ObjectId } from '../bson';
import type { Collection } from '../collection';
import type { FindCursor } from '../cursor/find_cursor';
import type { ReadPreference } from '../read_preference';
import type { Sort } from '../sort';
import type { Callback } from '../utils';
import type { GridFSChunk } from './upload';
/** @public */
export interface GridFSBucketReadStreamOptions {
    sort?: Sort;
    skip?: number;
    /** 0-based offset in bytes to start streaming from */
    start?: number;
    /** 0-based offset in bytes to stop streaming before */
    end?: number;
}
/** @public */
export interface GridFSBucketReadStreamOptionsWithRevision extends GridFSBucketReadStreamOptions {
    /** The revision number relative to the oldest file with the given filename. 0
     * gets you the oldest file, 1 gets you the 2nd oldest, -1 gets you the
     * newest. */
    revision?: number;
}
/** @public */
export interface GridFSFile {
    _id: ObjectId;
    length: number;
    chunkSize: number;
    filename: string;
    contentType?: string;
    aliases?: string[];
    metadata?: Document;
    uploadDate: Date;
}
/** @internal */
export interface GridFSBucketReadStreamPrivate {
    bytesRead: number;
    bytesToTrim: number;
    bytesToSkip: number;
    chunks: Collection<GridFSChunk>;
    cursor?: FindCursor<GridFSChunk>;
    expected: number;
    files: Collection<GridFSFile>;
    filter: Document;
    init: boolean;
    expectedEnd: number;
    file?: GridFSFile;
    options: {
        sort?: Sort;
        skip?: number;
        start: number;
        end: number;
    };
    readPreference?: ReadPreference;
}
/**
 * A readable stream that enables you to read buffers from GridFS.
 *
 * Do not instantiate this class directly. Use `openDownloadStream()` instead.
 * @public
 */
export declare class GridFSBucketReadStream extends Readable implements NodeJS.ReadableStream {
    /** @internal */
    s: GridFSBucketReadStreamPrivate;
    /**
     * An error occurred
     * @event
     */
    static readonly ERROR: "error";
    /**
     * Fires when the stream loaded the file document corresponding to the provided id.
     * @event
     */
    static readonly FILE: "file";
    /**
     * Emitted when a chunk of data is available to be consumed.
     * @event
     */
    static readonly DATA: "data";
    /**
     * Fired when the stream is exhausted (no more data events).
     * @event
     */
    static readonly END: "end";
    /**
     * Fired when the stream is exhausted and the underlying cursor is killed
     * @event
     */
    static readonly CLOSE: "close";
    /** @internal
     * @param chunks - Handle for chunks collection
     * @param files - Handle for files collection
     * @param readPreference - The read preference to use
     * @param filter - The filter to use to find the file document
     */
    constructor(chunks: Collection<GridFSChunk>, files: Collection<GridFSFile>, readPreference: ReadPreference | undefined, filter: Document, options?: GridFSBucketReadStreamOptions);
    /**
     * Reads from the cursor and pushes to the stream.
     * Private Impl, do not call directly
     * @internal
     */
    _read(): void;
    /**
     * Sets the 0-based offset in bytes to start streaming from. Throws
     * an error if this stream has entered flowing mode
     * (e.g. if you've already called `on('data')`)
     *
     * @param start - 0-based offset in bytes to start streaming from
     */
    start(start?: number): this;
    /**
     * Sets the 0-based offset in bytes to start streaming from. Throws
     * an error if this stream has entered flowing mode
     * (e.g. if you've already called `on('data')`)
     *
     * @param end - Offset in bytes to stop reading at
     */
    end(end?: number): this;
    /**
     * Marks this stream as aborted (will never push another `data` event)
     * and kills the underlying cursor. Will emit the 'end' event, and then
     * the 'close' event once the cursor is successfully killed.
     *
     * @param callback - called when the cursor is successfully closed or an error occurred.
     */
    abort(callback?: Callback<void>): void;
}
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