stylus/content/style-injector.js
2020-10-12 22:04:50 +03:00

448 lines
12 KiB
JavaScript

/* global prefs */
'use strict';
self.createStyleInjector = self.INJECTED === 1 ? self.createStyleInjector : ({
compare,
onUpdate = () => {},
}) => {
const PREFIX = 'stylus-';
const PATCH_ID = 'transition-patch';
// styles are out of order if any of these elements is injected between them
const ORDERED_TAGS = new Set(['head', 'body', 'frameset', 'style', 'link']);
// detect Chrome 65 via a feature it added since browser version can be spoofed
const isChromePre65 = chrome.app && typeof Worklet !== 'function';
const docRewriteObserver = RewriteObserver(_sort);
const docRootObserver = RootObserver(_sortIfNeeded);
const list = [];
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;
return {
list,
apply(styleMap) {
if ('ASS' in styleMap) _init(styleMap);
const styles = _styleMapToArray(styleMap);
return (
!styles.length ?
Promise.resolve([]) :
docRootObserver.evade(() => {
if (!isTransitionPatched && isEnabled) {
_applyTransitionPatch(styles);
}
return styles.map(_addUpdate);
})
).then(_emitUpdate);
},
clear() {
_addRemoveElements(false);
list.length = 0;
table.clear();
_emitUpdate();
},
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) {
el.remove();
}
}
},
remove(id) {
_remove(id);
_emitUpdate();
},
replace(styleMap) {
const styles = _styleMapToArray(styleMap);
const added = new Set(styles.map(s => s.id));
const removed = [];
for (const style of list) {
if (!added.has(style.id)) {
removed.push(style.id);
}
}
styles.forEach(_addUpdate);
removed.forEach(_remove);
_emitUpdate();
},
toggle(enable) {
if (isEnabled === enable) return;
isEnabled = enable;
if (!enable) _toggleObservers(false);
_addRemoveElements(enable);
if (enable) _toggleObservers(true);
},
};
function _add(style) {
_domCreate(style);
const i = list.findIndex(item => compare(item, style) > 0);
table.set(style.id, style);
if (isEnabled) _domInsert(style, (list[i] || {}).el);
list.splice(i < 0 ? list.length : i, 0, style);
return style.el;
}
function _addRemoveElements(add) {
const asses = [];
for (const style of list) {
if (style.ass) {
asses.push(style.el);
} else if (add) {
_domInsert(style);
} else {
_domDelete(style);
}
}
if (ASS) {
ASS.list = ASS.wipedList.concat(add ? asses : []);
}
}
function _addUpdate(style) {
return table.has(style.id) ? _update(style) : _add(style);
}
function _applyTransitionPatch(styles) {
isTransitionPatched = true;
// CSS transition bug workaround: since we insert styles asynchronously,
// the browsers, especially Firefox, may apply all transitions on page load
if (document.readyState === 'complete' ||
document.visibilityState === 'hidden' ||
!styles.some(s => s.code.includes('transition'))) {
return;
}
const style = {
id: PATCH_ID,
code: `
:root:not(#\\0):not(#\\0) * {
transition: none !important;
}
`,
};
_domCreate(style);
_domInsert(style);
// wait for the next paint to complete
// note: requestAnimationFrame won't fire in inactive tabs
requestAnimationFrame(() => setTimeout(_domDelete, 0, style));
}
/**
* @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');
} else if (document instanceof XMLDocument) {
// XML document style
el = createElementNS.call(creationDoc, 'http://www.w3.org/1999/xhtml', 'style');
} else {
// HTML document style; also works on HTML-embedded SVG
el = createElement.call(creationDoc, 'style');
}
if (id) {
el.id = `${PREFIX}${id}`;
const oldEl = document.getElementById(el.id);
if (oldEl) oldEl.id += '-superseded-by-Stylus';
}
el.type = 'text/css';
// 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]();
docRootObserver[onOff]();
}
function _emitUpdate(value) {
_toggleObservers(list.length);
onUpdate();
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
https://bugzilla.mozilla.org/show_bug.cgi?id=1579345#c3
and since userAgent.navigator can be spoofed via about:config or devtools,
we're checking for getPreventDefault that was removed in FF59
*/
function _initCreationDoc() {
creationDoc = !Event.prototype.getPreventDefault && document.wrappedJSObject;
if (creationDoc) {
({createElement, createElementNS} = creationDoc);
const el = document.documentElement.appendChild(_domCreate());
const isApplied = el.sheet;
el.remove();
if (isApplied) return;
}
creationDoc = document;
({createElement, createElementNS} = document);
}
function _remove(id) {
const style = table.get(id);
if (!style) return;
table.delete(id);
list.splice(list.indexOf(style), 1);
_domDelete(style);
}
function _sort() {
docRootObserver.evade(() => {
list.sort(compare);
_addRemoveElements(true);
});
}
function _sortIfNeeded() {
let needsSort;
let el = list.length && list[0].el;
if (!el) {
needsSort = false;
} else if (el.parentNode !== creationDoc.documentElement) {
needsSort = true;
} else {
let i = 0;
while (el) {
if (i < list.length && el === list[i].el) {
i++;
} else if (ORDERED_TAGS.has(el.localName)) {
needsSort = true;
break;
}
el = el.nextElementSibling;
}
// some styles are not injected to the document
if (i < list.length) needsSort = true;
}
if (needsSort) _sort();
return needsSort;
}
function _styleMapToArray(styleMap) {
return Object.values(styleMap).map(s => ({
id: s.id,
code: s.code.join(''),
}));
}
function _update({id, code}) {
const style = table.get(id);
if (style.code === code) return;
style.code = code;
// workaround for Chrome devtools bug fixed in v65
if (isChromePre65) {
const oldEl = style.el;
style.el = _domCreate({id, code});
if (isEnabled) {
oldEl.parentNode.insertBefore(style.el, oldEl.nextSibling);
oldEl.remove();
}
} else if (!style.ass) {
style.el.textContent = code;
} else if (!_setASSCode(style, code)) {
_remove(id);
_add(style);
}
}
function RewriteObserver(onChange) {
// detect documentElement being rewritten from inside the script
let root;
let observing = false;
let timer;
const observer = new MutationObserver(_check);
return {start, stop};
function start() {
if (observing) return;
// detect dynamic iframes rewritten after creation by the embedder i.e. externally
root = document.documentElement;
timer = setTimeout(_check);
observer.observe(document, {childList: true});
observing = true;
}
function stop() {
if (!observing) return;
clearTimeout(timer);
observer.disconnect();
observing = false;
}
function _check() {
if (root !== document.documentElement) {
root = document.documentElement;
onChange();
}
}
}
function RootObserver(onChange) {
let digest = 0;
let lastCalledTime = NaN;
let observing = false;
let observer;
return {evade, start, stop};
function create() {
observer = new MutationObserver(() => {
if (digest) {
if (performance.now() - lastCalledTime > 1000) {
digest = 0;
} else if (digest > 5) {
throw new Error('The page keeps generating mutations. Skip the event.');
}
}
if (onChange()) {
digest++;
lastCalledTime = performance.now();
}
});
}
function evade(fn) {
const restore = observing && start;
stop();
return new Promise(resolve => _run(fn, resolve, _waitForRoot))
.then(restore);
}
function start() {
if (observing || ASS && ASS.isTight) return;
if (!observer) create();
observer.observe(document.documentElement, {childList: true});
observing = true;
}
function stop() {
if (!observing) return;
// FIXME: do we need this?
observer.takeRecords();
observer.disconnect();
observing = false;
}
function _run(fn, resolve, wait) {
if (document.documentElement) {
resolve(fn());
return true;
}
if (wait) wait(fn, resolve);
}
function _waitForRoot(...args) {
new MutationObserver((_, observer) => _run(...args) && observer.disconnect())
.observe(document, {childList: true});
}
}
};