/// <reference types="node" />
import { ContextFile } from '../context-file';
export type StrategyFunction = (commonAncestorFile: ContextFile | undefined, existingFile: ContextFile | undefined, proposedFile: ContextFile | undefined, options?: {}) => ContextFile | undefined;
export declare class MergeStrategies {
    /**
     * A strategy that always resolves to the proposed file.
     * @returns the proposed file.
     */
    static alwaysUpdate: StrategyFunction;
    /**
     * A strategy that always resolves to the existing file.
     * @returns the existing file.
     */
    static neverUpdate: StrategyFunction;
    /**
     * A strategy that resolves to the proposed file when an existing file does not exist already.
     * Otherwise, resolves to the existing file.
     */
    static onlyAdd: StrategyFunction;
    /**
     * A strategy that performs a three way merge between the existing, proposed, and common
     * ancestor files. The resolved file may contain conflict markers if the files can not be
     * cleanly merged.
     *
     * The provided files' contents must be UTF-8 encoded in order for the strategy to produce
     * meaningful output. The strategy attempts to detect if the input files are binary. If
     * the strategy detects a merge conflict in a binary file, it always returns the
     * proposedFile.
     */
    static threeWayMerge: StrategyFunction;
    /**
     * A strategy that performs a three way merge between the existing, proposed, and common
     * ancestor files. This strategy resolves conflicts by selecting the proposedFile's side
     * of each conflict.
     */
    static preferProposed: StrategyFunction;
    /**
     * A strategy that performs a three way merge between the existing, proposed, and common
     * ancestor files. This strategy resolves conflicts by selecting the existingFile's side
     * of each conflict.
     */
    static preferExisting: StrategyFunction;
}
/**
 * Returns whether the given Buffer is binary or not using a heuristic based
 * approach of checking for null bytes in the beginning of the file contents.
 */
export declare function isBinary(fileBuffer?: Buffer): boolean;