@adguard/agtree/dist/utils/cosmetic-rule-separator.js

Tool set for working with adblock filter lists

/*
 * AGTree v3.4.3 (build date: Thu, 11 Dec 2025 13:43:19 GMT)
 * (c) 2025 Adguard Software Ltd.
 * Released under the MIT license
 * https://github.com/AdguardTeam/tsurlfilter/tree/master/packages/agtree#readme
 */
import { CosmeticRuleSeparator } from '../nodes/index.js';
import { AT_SIGN, SPACE } from './constants.js';

/**
 * @file Cosmetic rule separator finder and categorizer
 */
/**
 * Utility class for cosmetic rule separators.
 */
class CosmeticRuleSeparatorUtils {
    /**
     * Checks whether the specified separator is an exception.
     *
     * @param separator Separator to check
     * @returns `true` if the separator is an exception, `false` otherwise
     */
    static isException(separator) {
        // Simply check the second character
        return separator[1] === AT_SIGN;
    }
    /**
     * Checks whether the specified separator is marks an Extended CSS cosmetic rule.
     *
     * @param separator Separator to check
     * @returns `true` if the separator is marks an Extended CSS cosmetic rule, `false` otherwise
     */
    static isExtendedCssMarker(separator) {
        return (separator === CosmeticRuleSeparator.ExtendedElementHiding
            || separator === CosmeticRuleSeparator.ExtendedElementHidingException
            || separator === CosmeticRuleSeparator.AdgExtendedCssInjection
            || separator === CosmeticRuleSeparator.AdgExtendedCssInjectionException);
    }
    /**
     * Looks for the cosmetic rule separator in the rule. This is a simplified version that
     * masks the recursive function.
     *
     * @param rule Raw rule
     * @returns Separator result or null if no separator was found
     */
    static find(rule) {
        /**
         * Helper function to create results of the `find` method.
         *
         * @param start Start position
         * @param separator Separator type
         * @returns Cosmetic rule separator node
         */
        // eslint-disable-next-line max-len
        function createResult(start, separator) {
            return {
                separator,
                start,
                end: start + separator.length,
            };
        }
        for (let i = 0; i < rule.length; i += 1) {
            if (rule[i] === '#') {
                if (rule[i + 1] === '#' && rule[i - 1] !== SPACE) {
                    // ##
                    return createResult(i, CosmeticRuleSeparator.ElementHiding);
                }
                if (rule[i + 1] === '?' && rule[i + 2] === '#') {
                    // #?#
                    return createResult(i, CosmeticRuleSeparator.ExtendedElementHiding);
                }
                if (rule[i + 1] === '%' && rule[i + 2] === '#') {
                    // #%#
                    return createResult(i, CosmeticRuleSeparator.AdgJsInjection);
                }
                if (rule[i + 1] === '$') {
                    if (rule[i + 2] === '#') {
                        // #$#
                        return createResult(i, CosmeticRuleSeparator.AdgCssInjection);
                    }
                    if (rule[i + 2] === '?' && rule[i + 3] === '#') {
                        // #$?#
                        return createResult(i, CosmeticRuleSeparator.AdgExtendedCssInjection);
                    }
                }
                // Exceptions
                if (rule[i + 1] === '@') {
                    if (rule[i + 2] === '#' && rule[i - 1] !== SPACE) {
                        // #@#
                        return createResult(i, CosmeticRuleSeparator.ElementHidingException);
                    }
                    if (rule[i + 2] === '?' && rule[i + 3] === '#') {
                        // #@?#
                        return createResult(i, CosmeticRuleSeparator.ExtendedElementHidingException);
                    }
                    if (rule[i + 2] === '%' && rule[i + 3] === '#') {
                        // #@%#
                        return createResult(i, CosmeticRuleSeparator.AdgJsInjectionException);
                    }
                    if (rule[i + 2] === '$') {
                        if (rule[i + 3] === '#') {
                            // #@$#
                            return createResult(i, CosmeticRuleSeparator.AdgCssInjectionException);
                        }
                        if (rule[i + 3] === '?' && rule[i + 4] === '#') {
                            // #@$?#
                            return createResult(i, CosmeticRuleSeparator.AdgExtendedCssInjectionException);
                        }
                    }
                }
            }
            if (rule[i] === '$') {
                if (rule[i + 1] === '$') {
                    // $$
                    return createResult(i, CosmeticRuleSeparator.AdgHtmlFiltering);
                }
                if (rule[i + 1] === '@' && rule[i + 2] === '$') {
                    // $@$
                    return createResult(i, CosmeticRuleSeparator.AdgHtmlFilteringException);
                }
            }
        }
        return null;
    }
}

export { CosmeticRuleSeparatorUtils };