import { FetchOptions } from './Fetcher';
import { Project } from './Project';
import { Report } from './Report';
import { Descriptor, Locator, Package, DescriptorHash } from './types';
export declare type MinimalResolveOptions = {
    project: Project;
    resolver: Resolver;
};
export declare type ResolveOptions = MinimalResolveOptions & {
    fetchOptions?: FetchOptions | null;
    report: Report;
};
/**
 * Resolvers are the components that do all the lifting needed in order to
 * produce a lockfile. In clear, they transfom the following:
 *
 *   webpack@^4.0.0
 *
 * into this:
 *
 *   webpack@4.28.0 | dependencies: ajv@^6.1.0, ajv-keyword@^3.1.0, ...
 *
 * In order to do this, they have three different data structures used to
 * represents the various states of the package resolution:
 *
 *   - **Descriptors** contain a package name and a range (for example, using
 *     the previous example, "^4.0.0" would be the range). This range might
 *     point to multiple possible resolutions, so a descriptor alone isn't
 *     enough to fetch the package data from its remote location.
 *
 *   - **Locators** contain a package name and a reference that is used to
 *     both uniquely identify a package and fetch it from its remote location.
 *     To keep using the same example, "4.28.0" would be the reference. Note
 *     that locators have a funny property: they also are valid descriptors!
 *
 *   - **Packages** are locators that made it big. While locators are quite
 *     small, package definitions are relatively fat and contain much more
 *     information than their cousins - for example the dependency list of the
 *     package.
 */
export interface Resolver {
    /**
     * This function must return true if the specified descriptor is meant to be
     * turned into a locator by this resolver. The other functions (except its
     * locator counterpart) won't be called if it returns false.
     *
     * @param descriptor The descriptor that needs to be validated.
     * @param opts The resolution options.
     */
    supportsDescriptor(descriptor: Descriptor, opts: MinimalResolveOptions): boolean;
    /**
     * This function must return true if the specified locator is meant to be
     * turned into a package definition by this resolver. The other functions
     * (except its locator counterpart) won't be called if it returns false.
     *
     * @param locator The locator that needs to be validated.
     * @param opts The resolution options.
     */
    supportsLocator(locator: Locator, opts: MinimalResolveOptions): boolean;
    /**
     * This function indicates whether the package definition for the specified
     * locator must be kept between installs. You typically want to return true
     * for all packages that are cached, but return false for all packages that
     * hydrate packages directly from the filesystem (for example workspaces).
     *
     * Note that even packages returning false are stored within the lockfile!
     * The difference is that when a new install is done, all package definitions
     * that return false will be discarded and resolved again (their potential
     * cache data will be kept, though).
     *
     * @param locator The queried package.
     * @param opts The resolution options.
     */
    shouldPersistResolution(locator: Locator, opts: MinimalResolveOptions): boolean;
    /**
     * This function is called for each dependency present in the dependency list
     * of a package definition. If it returns a new descriptor, this new
     * descriptor will be used
     *
     * Note that `fromLocator` is not necessarily a locator that's supported by
     * the resolver. It simply is the locator of the package that depends on the
     * specified descriptor, regardless who owns it.
     *
     * A typical case where you will want to use this function is when your
     * resolver must support relative paths (for example the `link:` protocol).
     * In this situation, you'll want to store the `fromLocator` in the bound
     * descriptor in order to be able to access the right location during the
     * next steps of the resolution.
     *
     * @param descriptor The depended descriptor.
     * @param fromLocator The dependent locator.
     * @param opts The resolution options.
     */
    bindDescriptor(descriptor: Descriptor, fromLocator: Locator, opts: MinimalResolveOptions): Descriptor;
    /**
     * This function must return a set of other descriptors that must be
     * transformed into locators before the subject descriptor can be transformed
     * into a locator. This is typically only needed for transform packages, as
     * you need to know the original resolution in order to copy it.
     */
    getResolutionDependencies(descriptor: Descriptor, opts: MinimalResolveOptions): Array<Descriptor>;
    /**
     * This function will, given a descriptor, return the list of locators that
     * potentially satisfy it.
     *
     * The returned array must be sorted in such a way that the preferred
     * locators are first. This will cause the resolution algorithm to prioritize
     * them if possible (it doesn't guarantee that they'll end up being used).
     *
     * @param descriptor The source descriptor.
     * @param dependencies The resolution dependencies and their resolutions.
     * @param opts The resolution options.
     */
    getCandidates(descriptor: Descriptor, dependencies: Map<DescriptorHash, Package>, opts: ResolveOptions): Promise<Array<Locator>>;
    /**
     * This function will, given a locator, return the full package definition
     * for the package pointed at.
     *
     * @param locator The source locator.
     * @param opts The resolution options.
     */
    resolve(locator: Locator, opts: ResolveOptions): Promise<Package>;
}