shell bypass 403
/**
* The MIT License (MIT)
* Copyright (c) 2017-present Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
*/
'use strict';
var clone = require('../utils/clone');
var parser = require('../parser');
var transform = require('../transform');
var optimizationTransforms = require('./transforms');
module.exports = {
/**
* Optimizer transforms a regular expression into an optimized version,
* replacing some sub-expressions with their idiomatic patterns.
*
* @param string | RegExp | AST - a regexp to optimize.
*
* @return TransformResult - an optimized regexp.
*
* Example:
*
* /[a-zA-Z_0-9][a-zA-Z_0-9]*\e{1,}/
*
* Optimized to:
*
* /\w+e+/
*/
optimize: function optimize(regexp) {
var _ref = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {},
_ref$whitelist = _ref.whitelist,
whitelist = _ref$whitelist === undefined ? [] : _ref$whitelist,
_ref$blacklist = _ref.blacklist,
blacklist = _ref$blacklist === undefined ? [] : _ref$blacklist;
var transformsRaw = whitelist.length > 0 ? whitelist : Array.from(optimizationTransforms.keys());
var transformToApply = transformsRaw.filter(function (transform) {
return !blacklist.includes(transform);
});
var ast = regexp;
if (regexp instanceof RegExp) {
regexp = '' + regexp;
}
if (typeof regexp === 'string') {
ast = parser.parse(regexp);
}
var result = new transform.TransformResult(ast);
var prevResultString = void 0;
do {
// Get a copy of the current state here so
// we can compare it with the state at the
// end of the loop.
prevResultString = result.toString();
ast = clone(result.getAST());
transformToApply.forEach(function (transformName) {
if (!optimizationTransforms.has(transformName)) {
throw new Error('Unknown optimization-transform: ' + transformName + '. ' + 'Available transforms are: ' + Array.from(optimizationTransforms.keys()).join(', '));
}
var transformer = optimizationTransforms.get(transformName);
// Don't override result just yet since we
// might want to rollback the transform
var newResult = transform.transform(ast, transformer);
if (newResult.toString() !== result.toString()) {
if (newResult.toString().length <= result.toString().length) {
result = newResult;
} else {
// Result has changed but is not shorter:
// restore ast to its previous state.
ast = clone(result.getAST());
}
}
});
// Keep running the optimizer until it stops
// making any change to the regexp.
} while (result.toString() !== prevResultString);
return result;
}
};