stylus/content/install-user-css.js
2017-09-25 20:01:50 +08:00

124 lines
2.8 KiB
JavaScript

'use strict';
function runtimeSend(request) {
return new Promise((resolve, reject) => {
chrome.runtime.sendMessage(
request,
({status, result}) => (status === 'error' ? reject : resolve)(result)
);
});
}
function createSourceLoader() {
let source;
function fetchText(url) {
return new Promise((resolve, reject) => {
// you can't use fetch in Chrome under 'file:' protocol
const xhr = new XMLHttpRequest();
xhr.open('GET', url);
xhr.addEventListener('load', () => resolve(xhr.responseText));
xhr.addEventListener('error', () => reject(xhr));
xhr.send();
});
}
function load() {
return fetchText(location.href)
.then(_source => {
source = _source;
return source;
});
}
function watch(cb) {
let timer;
const DELAY = 1000;
function start() {
if (timer) {
return;
}
timer = setTimeout(check, DELAY);
}
function stop() {
clearTimeout(timer);
timer = null;
}
function check() {
fetchText(location.href)
.then(_source => {
if (source !== _source) {
source = _source;
return cb(source);
}
})
.catch(console.log)
.then(() => {
timer = setTimeout(check, DELAY);
});
}
return {start, stop};
}
return {load, watch, source: () => source};
}
function initUsercssInstall() {
const sourceLoader = createSourceLoader();
const pendingSource = sourceLoader.load();
let watcher;
chrome.runtime.onConnect.addListener(port => {
// FIXME: is this the correct way to reject a connection?
// https://developer.chrome.com/extensions/messaging#connect
console.assert(port.name === 'usercss-install');
port.onMessage.addListener(msg => {
switch (msg.method) {
case 'getSourceCode':
pendingSource.then(sourceCode =>
port.postMessage({method: msg.method + 'Response', sourceCode})
).catch(err =>
port.postMessage({method: msg.method + 'Response', error: err.message || String(err)})
);
break;
case 'liveReloadStart':
if (!watcher) {
watcher = sourceLoader.watch(sourceCode => {
port.postMessage({method: 'sourceCodeChanged', sourceCode});
});
}
watcher.start();
break;
case 'liveReloadStop':
watcher.stop();
break;
}
});
});
return runtimeSend({
method: 'openUsercssInstallPage',
updateUrl: location.href
}).catch(alert);
}
function isUsercss() {
if (!/text\/(css|plain)/.test(document.contentType)) {
return false;
}
if (!/==userstyle==/i.test(document.body.textContent)) {
return false;
}
return true;
}
if (isUsercss()) {
initUsercssInstall();
}