import { injectable, inject } from 'inversify';
import { ServiceIdentifiers } from '../../../container/ServiceIdentifiers';
import { ICustomNodeGroup } from '../../../interfaces/custom-nodes/ICustomNodeGroup';
import { IEncodedValue } from '../../../interfaces/node-transformers/IEncodedValue';
import { IOptions } from '../../../interfaces/options/IOptions';
import { IStorage } from '../../../interfaces/storages/IStorage';
import { StringArrayEncoding } from '../../../enums/StringArrayEncoding';
import { AbstractReplacer } from './AbstractReplacer';
import { CryptUtils } from '../../../utils/CryptUtils';
import { RandomGeneratorUtils } from '../../../utils/RandomGeneratorUtils';
import { Utils } from '../../../utils/Utils';
@injectable()
export class StringLiteralReplacer extends AbstractReplacer {
/**
* @type {number}
*/
private static readonly minimumLengthForStringArray: number = 3;
/**
* @type {string[]}
*/
private static readonly rc4Keys: string[] = RandomGeneratorUtils.getRandomGenerator()
.n(() => RandomGeneratorUtils.getRandomGenerator().string({length: 4}), 50);
/**
* @type {Map<string, string>}
*/
private readonly stringLiteralCache: Map <string, string> = new Map();
/**
* @type {Map<string, string>}
*/
private readonly stringLiteralHexadecimalIndexCache: Map <string, string> = new Map();
/**
* @type {IStorage<ICustomNodeGroup>}
*/
private readonly customNodeGroupStorage: IStorage<ICustomNodeGroup>;
/**
* @type {IStorage<string>}
*/
private readonly stringArrayStorage: IStorage<string>;
/**
* @param customNodeGroupStorage
* @param stringArrayStorage
* @param options
*/
constructor (
@inject(ServiceIdentifiers.TCustomNodeGroupStorage) customNodeGroupStorage: IStorage<ICustomNodeGroup>,
@inject(ServiceIdentifiers.TStringArrayStorage) stringArrayStorage: IStorage<string>,
@inject(ServiceIdentifiers.IOptions) options: IOptions
) {
super(options);
this.customNodeGroupStorage = customNodeGroupStorage;
this.stringArrayStorage = stringArrayStorage;
}
/**
* @param nodeValue
* @returns {string}
*/
public replace (nodeValue: string): string {
const usingStringArray: boolean = (
this.options.stringArray &&
nodeValue.length >= StringLiteralReplacer.minimumLengthForStringArray &&
RandomGeneratorUtils.getRandomFloat(0, 1) <= this.options.stringArrayThreshold
);
const cacheKey: string = `${nodeValue}-${String(usingStringArray)}`;
if (this.stringLiteralCache.has(cacheKey) && this.options.stringArrayEncoding !== StringArrayEncoding.rc4) {
return <string>this.stringLiteralCache.get(cacheKey);
}
let result: string;
if (usingStringArray) {
result = this.replaceStringLiteralWithStringArrayCall(nodeValue);
} else {
result = `'${Utils.stringToUnicodeEscapeSequence(nodeValue, !this.options.unicodeEscapeSequence)}'`;
}
this.stringLiteralCache.set(cacheKey, result);
return result;
}
/**
* @param value
* @return {string}
*/
private getArrayHexadecimalIndex (value: string): string {
if (this.stringLiteralHexadecimalIndexCache.has(value)) {
return <string>this.stringLiteralHexadecimalIndexCache.get(value);
}
const indexOfValue: number = this.stringArrayStorage.getLength();
const hexadecimalIndex: string = `${Utils.hexadecimalPrefix}${Utils.decToHex(indexOfValue)}`;
this.stringArrayStorage.set(null, value);
this.stringLiteralHexadecimalIndexCache.set(value, hexadecimalIndex);
return hexadecimalIndex;
}
/**
* @param value
* @returns {IEncodedValue}
*/
private getEncodedValue (value: string): IEncodedValue {
let encodedValue: string,
key: string | undefined;
switch (this.options.stringArrayEncoding) {
case StringArrayEncoding.rc4:
key = RandomGeneratorUtils.getRandomGenerator().pickone(StringLiteralReplacer.rc4Keys);
encodedValue = CryptUtils.btoa(CryptUtils.rc4(value, key));
break;
case StringArrayEncoding.base64:
encodedValue = CryptUtils.btoa(value);
break;
default:
encodedValue = value;
}
encodedValue = Utils.stringToUnicodeEscapeSequence(encodedValue, !this.options.unicodeEscapeSequence);
return { encodedValue, key };
}
/**
* @param value
* @returns {string}
*/
private replaceStringLiteralWithStringArrayCall (value: string): string {
const { encodedValue, key }: IEncodedValue = this.getEncodedValue(value);
const hexadecimalIndex: string = this.getArrayHexadecimalIndex(encodedValue);
const rotatedStringArrayStorageId: string = Utils.stringRotate(this.stringArrayStorage.getStorageId(), 1);
const stringArrayStorageCallsWrapperName: string = `_${Utils.hexadecimalPrefix}${rotatedStringArrayStorageId}`;
if (key) {
return `${stringArrayStorageCallsWrapperName}('${hexadecimalIndex}', '${Utils.stringToUnicodeEscapeSequence(key, !this.options.unicodeEscapeSequence)}')`;
}
return `${stringArrayStorageCallsWrapperName}('${hexadecimalIndex}')`;
}
}
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