enigma-bbs/core/file_util.js

/* jslint node: true */
'use strict';

//	ENiGMA½
const EnigAssert	= require('./enigma_assert.js');

//	deps
const fse			= require('fs-extra');
const paths			= require('path');
const async			= require('async');

exports.moveFileWithCollisionHandling		= moveFileWithCollisionHandling;
exports.copyFileWithCollisionHandling		= copyFileWithCollisionHandling;
exports.pathWithTerminatingSeparator		= pathWithTerminatingSeparator;

function moveOrCopyFileWithCollisionHandling(src, dst, operation, cb) {
    operation			= operation || 'copy';
    const dstPath		= paths.dirname(dst);
    const dstFileExt	= paths.extname(dst);
    const dstFileSuffix	= paths.basename(dst, dstFileExt);

    EnigAssert('move' === operation || 'copy' === operation);

    let renameIndex		= 0;
    let opOk			= false;
    let tryDstPath;

    function tryOperation(src, dst, callback) {
        if('move' === operation) {
            fse.move(src, tryDstPath, err => {
                return callback(err);
            });
        } else if('copy' === operation) {
            fse.copy(src, tryDstPath, { overwrite : false, errorOnExist : true }, err => {
                return callback(err);
            });
        }
    }

    async.until(
        () => opOk,	//	until moved OK
        (cb) => {
            if(0 === renameIndex) {
                //	try originally supplied path first
                tryDstPath = dst;
            } else {
                tryDstPath = paths.join(dstPath, `${dstFileSuffix}(${renameIndex})${dstFileExt}`);
            }

            tryOperation(src, tryDstPath, err => {
                if(err) {
                    //	for some reason fs-extra copy doesn't pass err.code
                    //	:TODO: this is dangerous: submit a PR to fs-extra to set EEXIST
                    if('EEXIST' === err.code || 'copy' === operation) {
                        renameIndex += 1;
                        return cb(null);	//	keep trying
                    }

                    return cb(err);
                }

                opOk = true;
                return cb(null, tryDstPath);
            });
        },
        (err, finalPath) => {
            return cb(err, finalPath);
        }
    );
}

//
//	Move |src| -> |dst| renaming to file(1).ext, file(2).ext, etc.
//	in the case of collisions.
//
function moveFileWithCollisionHandling(src, dst, cb) {
    return moveOrCopyFileWithCollisionHandling(src, dst, 'move', cb);
}

function copyFileWithCollisionHandling(src, dst, cb) {
    return moveOrCopyFileWithCollisionHandling(src, dst, 'copy', cb);
}

function pathWithTerminatingSeparator(path) {
    if(path && paths.sep !== path.charAt(path.length - 1)) {
        path = path + paths.sep;
    }
    return path;
}