uBlock/platform/mv3/extension/js/utils.js

/*******************************************************************************

    uBlock Origin Lite - a comprehensive, MV3-compliant content blocker
    Copyright (C) 2022-present Raymond Hill

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see {http://www.gnu.org/licenses/}.

    Home: https://github.com/gorhill/uBlock
*/

import { browser } from './ext.js';

/******************************************************************************/

function parsedURLromOrigin(origin) {
    try {
        return new URL(origin);
    } catch {
    }
}

/******************************************************************************/

const toBroaderHostname = hn => {
    if ( hn === '*' ) { return ''; }
    const pos = hn.indexOf('.');
    return pos !== -1 ? hn.slice(pos+1) : '*';
};

/******************************************************************************/

// Is hna descendant hostname of hnb?

const isDescendantHostname = (hna, hnb) => {
    if ( hnb === 'all-urls' ) { return true; }
    if ( hna.endsWith(hnb) === false ) { return false; }
    if ( hna === hnb ) { return false; }
    return hna.charCodeAt(hna.length - hnb.length - 1) === 0x2E /* '.' */;
};

/**
 * Returns whether a hostname is part of a collection, or is descendant of an
 * item in the collection.
 * @param hna - the hostname representing the needle.
 * @param iterb - an iterable representing the haystack of hostnames.
 */

const isDescendantHostnameOfIter = (hna, iterb) => {
    const setb = iterb instanceof Set ? iterb : new Set(iterb);
    if ( setb.has('all-urls') || setb.has('*') ) { return true; }
    let hn = hna;
    while ( hn ) {
        const pos = hn.indexOf('.');
        if ( pos === -1 ) { break; }
        hn = hn.slice(pos + 1);
        if ( setb.has(hn) ) { return true; }
    }
    return false;
};

/**
 * Returns all hostnames in the first collection which are equal or descendant
 * of hostnames in the second collection.
 * @param itera - an iterable which hostnames must be filtered out.
 * @param iterb - an iterable which hostnames must be matched.
 */

const intersectHostnameIters = (itera, iterb) => {
    const setb = iterb instanceof Set ? iterb : new Set(iterb);
    if ( setb.has('all-urls') || setb.has('*') ) { return Array.from(itera); }
    const out = [];
    for ( const hna of itera ) {
        if ( setb.has(hna) || isDescendantHostnameOfIter(hna, setb) ) {
            out.push(hna);
        }
    }
    return out;
};

const subtractHostnameIters = (itera, iterb) => {
    const setb = iterb instanceof Set ? iterb : new Set(iterb);
    if ( setb.has('all-urls') || setb.has('*') ) { return []; }
    const out = [];
    for ( const hna of itera ) {
        if ( setb.has(hna) ) { continue; }
        if ( isDescendantHostnameOfIter(hna, setb) ) { continue; }
        out.push(hna);
    }
    return out;
};

/******************************************************************************/

const matchFromHostname = hn =>
    hn === '*' || hn === 'all-urls' ? '<all_urls>' : `*://*.${hn}/*`;

const matchesFromHostnames = hostnames => {
    const out = [];
    for ( const hn of hostnames ) {
        out.push(matchFromHostname(hn));
    }
    return out;
};

const hostnamesFromMatches = origins => {
    const out = [];
    for ( const origin of origins ) {
        if ( origin === '<all_urls>' ) {
            out.push('all-urls');
            continue;
        }
        const match = /^\*:\/\/(?:\*\.)?([^/]+)\/\*/.exec(origin);
        if ( match === null ) { continue; }
        out.push(match[1]);
    }
    return out;
};

/******************************************************************************/

const broadcastMessage = message => {
    const bc = new self.BroadcastChannel('uBOL');
    bc.postMessage(message);
};

/******************************************************************************/

// https://developer.mozilla.org/docs/Mozilla/Add-ons/WebExtensions/manifest.json/host_permissions#requested_permissions_and_user_prompts
// "Users can grant or revoke host permissions on an ad hoc basis. Therefore,
// most browsers treat host_permissions as optional."

async function hasBroadHostPermissions() {
    return browser.permissions.contains({ origins: [ '<all_urls>' ] });
}

/******************************************************************************/

export {
    broadcastMessage,
    parsedURLromOrigin,
    toBroaderHostname,
    isDescendantHostname,
    isDescendantHostnameOfIter,
    intersectHostnameIters,
    subtractHostnameIters,
    matchFromHostname,
    matchesFromHostnames,
    hostnamesFromMatches,
    hasBroadHostPermissions,
};