use adoptedStyleSheets

_locales/en/messages.json

@@ -943,6 +943,9 @@
   "optionsAdvanced": {
     "message": "Advanced"
   },
+  "optionsAdvancedAdoptedStyleSheets": {
+    "message": "Apply styles directly via <a href='https://developers.google.com/web/updates/2019/02/constructable-stylesheets'>AdoptedStyleSheets</a>"
+  },
   "optionsAdvancedContextDelete": {
     "message": "Add 'Delete' in editor context menu"
   },

background/style-manager.js

@@ -1,6 +1,6 @@
 /* eslint no-eq-null: 0, eqeqeq: [2, "smart"] */
 /* global createCache db calcStyleDigest db tryRegExp styleCodeEmpty styleSectionGlobal
-  getStyleWithNoCode msg sync uuidv4 URLS */
+  getStyleWithNoCode msg sync uuidv4 URLS prefs */
 /* exported styleManager */
 'use strict';
 
@@ -332,8 +332,10 @@ const styleManager = (() => {
   function ensurePrepared(methods) {
     const prepared = {};
     for (const [name, fn] of Object.entries(methods)) {
-      prepared[name] = (...args) =>
+      prepared[name] = async function () {
-        preparing.then(() => fn(...args));
+        await preparing;
+        return fn.apply(this, arguments);
+      };
     }
     return prepared;
   }
@@ -475,7 +477,7 @@ const styleManager = (() => {
     return result;
   }
 
-  function getSectionsByUrl(url, id) {
+  function getSectionsByUrl(url, id, checkASS) {
     let cache = cachedStyleForUrl.get(url);
     if (!cache) {
       cache = {
@@ -491,13 +493,12 @@ const styleManager = (() => {
           .map(i => styles.get(i))
       );
     }
-    if (id) {
+    const sections = id
-      if (cache.sections[id]) {
+      ? cache.sections[id] && {[id]: cache.sections[id]} || {}
-        return {[id]: cache.sections[id]};
+      : cache.sections;
-      }
+    return checkASS
-      return {};
+      ? Object.assign({ASS: prefs.get('adoptedStyleSheets')}, sections)
-    }
+      : sections;
-    return cache.sections;
 
     function buildCache(styleList) {
       const query = createMatchQuery(url);

content/apply.js

@@ -59,7 +59,7 @@ self.INJECTED !== 1 && (() => {
   function init() {
     return STYLE_VIA_API ?
       API.styleViaAPI({method: 'styleApply'}) :
-      API.getSectionsByUrl(getMatchUrl()).then(styleInjector.apply);
+      API.getSectionsByUrl(getMatchUrl(), null, true).then(styleInjector.apply);
   }
 
   function getMatchUrl() {

content/style-injector.js

@@ -1,3 +1,4 @@
+/* global prefs */
 'use strict';
 
 self.createStyleInjector = self.INJECTED === 1 ? self.createStyleInjector : ({
@@ -16,6 +17,7 @@ self.createStyleInjector = self.INJECTED === 1 ? self.createStyleInjector : ({
   const table = new Map();
   let isEnabled = true;
   let isTransitionPatched;
+  let ASS;
   // will store the original method refs because the page can override them
   let creationDoc, createElement, createElementNS;
 
@@ -24,6 +26,7 @@ self.createStyleInjector = self.INJECTED === 1 ? self.createStyleInjector : ({
     list,
 
     apply(styleMap) {
+      if ('ASS' in styleMap) _init(styleMap);
       const styles = _styleMapToArray(styleMap);
       return (
         !styles.length ?
@@ -45,6 +48,7 @@ self.createStyleInjector = self.INJECTED === 1 ? self.createStyleInjector : ({
     },
 
     clearOrphans() {
+      if (ASS) ASS.list = ASS.wipedList;
       for (const el of document.querySelectorAll(`style[id^="${PREFIX}"].stylus`)) {
         const id = el.id.slice(PREFIX.length);
         if (/^\d+$/.test(id) || id === PATCH_ID) {
@@ -82,24 +86,28 @@ self.createStyleInjector = self.INJECTED === 1 ? self.createStyleInjector : ({
   };
 
   function _add(style) {
-    const el = style.el = _createStyle(style.id, style.code);
+    _domCreate(style);
     const i = list.findIndex(item => compare(item, style) > 0);
     table.set(style.id, style);
-    if (isEnabled) {
+    if (isEnabled) _domInsert(style, (list[i] || {}).el);
-      document.documentElement.insertBefore(el, i < 0 ? null : list[i].el);
-    }
     list.splice(i < 0 ? list.length : i, 0, style);
-    return el;
+    return style.el;
   }
 
   function _addRemoveElements(add) {
-    for (const {el} of list) {
+    const asses = [];
-      if (add) {
+    for (const style of list) {
-        document.documentElement.appendChild(el);
+      if (style.ass) {
+        asses.push(style.el);
+      } else if (add) {
+        _domInsert(style);
       } else {
-        el.remove();
+        _domDelete(style);
       }
     }
+    if (ASS) {
+      ASS.list = ASS.wipedList.concat(add ? asses : []);
+    }
   }
 
   function _addUpdate(style) {
@@ -115,20 +123,35 @@ self.createStyleInjector = self.INJECTED === 1 ? self.createStyleInjector : ({
         !styles.some(s => s.code.includes('transition'))) {
       return;
     }
-    const el = _createStyle(PATCH_ID, `
+    const style = {
+      id: PATCH_ID,
+      code: `
         :root:not(#\\0):not(#\\0) * {
           transition: none !important;
         }
-    `);
+      `,
-    document.documentElement.appendChild(el);
+    };
+    _domCreate(style);
+    _domInsert(style);
     // wait for the next paint to complete
     // note: requestAnimationFrame won't fire in inactive tabs
-    requestAnimationFrame(() => setTimeout(() => el.remove()));
+    requestAnimationFrame(() => setTimeout(_domDelete, 0, style));
   }
 
-  function _createStyle(id, code = '') {
+  /**
-    if (!creationDoc) _initCreationDoc();
+   * @returns {Element|CSSStyleSheet}
+   * @mutates style
+   */
+  function _domCreate(style = {}) {
+    const {id, code = ''} = style;
     let el;
+    if (ASS) {
+      el = style.el = new CSSStyleSheet(id ? {media: PREFIX + id} : {});
+      if (_setASSCode(style, code)) {
+        return el;
+      }
+    }
+    if (!creationDoc) _initCreationDoc();
     if (document.documentElement instanceof SVGSVGElement) {
       // SVG document style
       el = createElementNS.call(creationDoc, 'http://www.w3.org/2000/svg', 'style');
@@ -148,9 +171,45 @@ self.createStyleInjector = self.INJECTED === 1 ? self.createStyleInjector : ({
     // SVG className is not a string, but an instance of SVGAnimatedString
     el.classList.add('stylus');
     el.textContent = code;
+    style.el = el;
+    style.ass = false;
     return el;
   }
 
+  function _domInsert({ass, el}, beforeEl) {
+    if (ass) {
+      const list = ASS.omit({el});
+      const i = list.indexOf(beforeEl);
+      list.splice(i >= 0 ? i : list.length, 0, el);
+      ASS.list = list;
+    } else {
+      document.documentElement.insertBefore(el, beforeEl);
+    }
+  }
+
+  function _domDelete({ass, el}) {
+    if (ass) {
+      ASS.omit({el, commit: true});
+    } else {
+      el.remove();
+    }
+  }
+
+  function _setASSCode(style, code) {
+    try {
+      style.el.replaceSync(code); // throws on @import per spec
+      style.ass = true;
+    } catch (err) {
+      style.ass = false;
+    }
+    const isTight = style.ass && list.every(s => s.ass);
+    if (ASS.isTight !== isTight) {
+      ASS.isTight = isTight;
+      docRootObserver[isTight ? 'stop' : 'start']();
+    }
+    return style.ass;
+  }
+
   function _toggleObservers(shouldStart) {
     const onOff = shouldStart && isEnabled ? 'start' : 'stop';
     docRewriteObserver[onOff]();
@@ -163,6 +222,51 @@ self.createStyleInjector = self.INJECTED === 1 ? self.createStyleInjector : ({
     return value;
   }
 
+
+  function _init(styleMap) {
+    if (ASS == null && Array.isArray(document.adoptedStyleSheets)) {
+      _initASS(styleMap.ASS);
+      prefs.subscribe(['adoptedStyleSheets'], (key, value) => {
+        _toggleObservers(false);
+        _addRemoveElements(false);
+        _initASS(value);
+        list.forEach(_domCreate);
+        if (isEnabled) _addRemoveElements(true);
+        _toggleObservers(true);
+      });
+    }
+    delete styleMap.ASS;
+  }
+
+  function _initASS(enable) {
+    if (ASS && !enable) {
+      ASS = false;
+    } else if (!ASS && enable) {
+      ASS = {
+        isTight: true,
+        /** @param {CSSStyleSheet[]} sheets */
+        set list(sheets) {
+          document.adoptedStyleSheets = sheets;
+        },
+        /** @returns {CSSStyleSheet[]} */
+        get list() {
+          return [...document.adoptedStyleSheets];
+        },
+        /** @returns {CSSStyleSheet[]} without our elements */
+        get wipedList() {
+          return ASS.list.filter(({media: {0: id = ''}}) =>
+            !(id.startsWith(PREFIX) && Number(id.slice(PREFIX.length)) || id.endsWith(PATCH_ID)));
+        },
+        omit({el, list = ASS.list, commit}) {
+          const i = list.indexOf(el);
+          if (i >= 0) list.splice(i, 1);
+          if (commit) ASS.list = list;
+          return list;
+        },
+      };
+    }
+  }
+
   /*
   FF59+ workaround: allow the page to read our sheets, https://github.com/openstyles/stylus/issues/461
   First we're trying the page context document where inline styles may be forbidden by CSP
@@ -174,7 +278,7 @@ self.createStyleInjector = self.INJECTED === 1 ? self.createStyleInjector : ({
     creationDoc = !Event.prototype.getPreventDefault && document.wrappedJSObject;
     if (creationDoc) {
       ({createElement, createElementNS} = creationDoc);
-      const el = document.documentElement.appendChild(_createStyle());
+      const el = document.documentElement.appendChild(_domCreate());
       const isApplied = el.sheet;
       el.remove();
       if (isApplied) return;
@@ -188,7 +292,7 @@ self.createStyleInjector = self.INJECTED === 1 ? self.createStyleInjector : ({
     if (!style) return;
     table.delete(id);
     list.splice(list.indexOf(style), 1);
-    style.el.remove();
+    _domDelete(style);
   }
 
   function _sort() {
@@ -237,13 +341,16 @@ self.createStyleInjector = self.INJECTED === 1 ? self.createStyleInjector : ({
     // workaround for Chrome devtools bug fixed in v65
     if (isChromePre65) {
       const oldEl = style.el;
-      style.el = _createStyle(id, code);
+      style.el = _domCreate({id, code});
       if (isEnabled) {
         oldEl.parentNode.insertBefore(style.el, oldEl.nextSibling);
         oldEl.remove();
       }
-    } else {
+    } else if (!style.ass) {
       style.el.textContent = code;
+    } else if (!_setASSCode(style, code)) {
+      _remove(id);
+      _add(style);
     }
   }
 
@@ -283,7 +390,11 @@ self.createStyleInjector = self.INJECTED === 1 ? self.createStyleInjector : ({
     let digest = 0;
     let lastCalledTime = NaN;
     let observing = false;
-    const observer = new MutationObserver(() => {
+    let observer;
+    return {evade, start, stop};
+
+    function create() {
+      observer = new MutationObserver(() => {
         if (digest) {
           if (performance.now() - lastCalledTime > 1000) {
             digest = 0;
@@ -296,7 +407,7 @@ self.createStyleInjector = self.INJECTED === 1 ? self.createStyleInjector : ({
           lastCalledTime = performance.now();
         }
       });
-    return {evade, start, stop};
+    }
 
     function evade(fn) {
       const restore = observing && start;
@@ -306,7 +417,8 @@ self.createStyleInjector = self.INJECTED === 1 ? self.createStyleInjector : ({
     }
 
     function start() {
-      if (observing) return;
+      if (observing || ASS && ASS.isTight) return;
+      if (!observer) create();
       observer.observe(document.documentElement, {childList: true});
       observing = true;
     }

js/prefs.js

@@ -9,6 +9,7 @@ self.prefs = self.INJECTED === 1 ? self.prefs : (() => {
     'disableAll': false,            // boss key
     'exposeIframes': false,         // Add 'stylus-iframe' attribute to HTML element in all iframes
     'newStyleAsUsercss': false,     // create new style in usercss format
+    'adoptedStyleSheets': false,    // try to apply styles via document.adoptedStyleSheets
 
     // checkbox in style config dialog
     'config.autosave': true,

options.html

@@ -232,6 +232,13 @@
         </h1>
       </div>
       <div class="items">
+        <label>
+          <span i18n-html="optionsAdvancedAdoptedStyleSheets"></span>
+          <span class="onoffswitch">
+            <input type="checkbox" id="adoptedStyleSheets" class="slider">
+            <span></span>
+          </span>
+        </label>
         <label>
           <span i18n-text="optionsAdvancedExposeIframes">
             <a data-cmd="note"

options/options.js

@@ -38,6 +38,10 @@ if (FIREFOX && 'update' in (chrome.commands || {})) {
   });
 }
 
+if (!Array.isArray(document.adoptedStyleSheets)) {
+  $('#adoptedStyleSheets').closest('label').classList.add('hidden');
+}
+
 // actions
 $('#options-close-icon').onclick = () => {
   top.dispatchEvent(new CustomEvent('closeOptions'));