stylus/background/storage.js

/* exported calcStyleDigest detectSloppyRegexps */
'use strict';

function normalizeStyleSections({sections}) {
  // retain known properties in an arbitrarily predefined order
  return (sections || []).map(section => ({
    code: section.code || '',
    urls: section.urls || [],
    urlPrefixes: section.urlPrefixes || [],
    domains: section.domains || [],
    regexps: section.regexps || [],
  }));
}

function calcStyleDigest(style) {
  const jsonString = style.usercssData ?
    style.sourceCode : JSON.stringify(normalizeStyleSections(style));
  const text = new TextEncoder('utf-8').encode(jsonString);
  return crypto.subtle.digest('SHA-1', text).then(hex);

  function hex(buffer) {
    const parts = [];
    const PAD8 = '00000000';
    const view = new DataView(buffer);
    for (let i = 0; i < view.byteLength; i += 4) {
      parts.push((PAD8 + view.getUint32(i).toString(16)).slice(-8));
    }
    return parts.join('');
  }
}

/*
  According to CSS4 @document specification the entire URL must match.
  Stylish-for-Chrome implemented it incorrectly since the very beginning.
  We'll detect styles that abuse the bug by finding the sections that
  would have been applied by Stylish but not by us as we follow the spec.
  Additionally we'll check for invalid regexps.
*/
function detectSloppyRegexps({matchUrl, ids}) {
  // TODO
}