import { FakeFS, PortablePath } from '@yarnpkg/fslib';
import { Cache } from './Cache';
import { Project } from './Project';
import { Report } from './Report';
import { LocatorHash, Locator } from './types';
export declare type MinimalFetchOptions = {
    project: Project;
    fetcher: Fetcher;
};
export declare type FetchOptions = MinimalFetchOptions & {
    cache: Cache;
    checksums: Map<LocatorHash, string>;
    report: Report;
};
export declare type FetchResult = {
    packageFs: FakeFS<PortablePath>;
    releaseFs?: () => void;
    prefixPath: PortablePath;
    localPath?: PortablePath | null;
    checksum?: string;
};
/**
 * Fetchers are the component tasked from taking a locator and fetching its
 * file data from whatever location the fetcher deems right. For example, the
 * npm fetcher would download them from the npm registry while the workspace
 * fetcher would simply return an plain link to the filesystem.
 */
export interface Fetcher {
    /**
     * This function must return true if the specified locator is understood by
     * this resolver (only its syntax is checked, it doesn't have to be valid
     * and it's fine if the `fetch` ends up returning a 404).
     *
     * @param locator The locator that needs to be validated.
     * @param opts The fetch options.
     */
    supports(locator: Locator, opts: MinimalFetchOptions): boolean;
    /**
     * This function must return the local path for the given package. The local
     * path is the one that's used to resolve relative dependency sources, for
     * example "file:./foo".
     *
     * @param locator The source locator.
     * @param opts The fetch options.
     */
    getLocalPath(locator: Locator, opts: FetchOptions): PortablePath | null;
    /**
     * This function must return a object describing where the package manager
     * can find the data for the specified package on disk.
     *
     * The return value is a more complex than a regular path (cf FetchResult)
     * because the fetchers are allowed to return virtual paths that point to
     * things that don't actually exist (for example directories stored within
     * zip archives).
     *
     * @param locator The source locator.
     * @param opts The fetch options.
     */
    fetch(locator: Locator, opts: FetchOptions): Promise<FetchResult>;
}