stylus/content/install-hook-usercss.js
2018-10-07 22:59:31 +08:00

106 lines
2.7 KiB
JavaScript

'use strict';
(() => {
// some weird bug in new Chrome: the content script gets injected multiple times
if (typeof window.initUsercssInstall === 'function') return;
if (!/text\/(css|plain)/.test(document.contentType) ||
!/==userstyle==/i.test(document.body.textContent)) {
return;
}
window.initUsercssInstall = () => {};
orphanCheck();
const DELAY = 500;
const url = location.href;
let sourceCode, port, timer;
chrome.runtime.onConnect.addListener(onConnected);
API.openUsercssInstallPage({url})
.catch(err => alert(err));
function onConnected(newPort) {
port = newPort;
port.onDisconnect.addListener(stop);
port.onMessage.addListener(onMessage);
}
function onMessage(msg, port) {
switch (msg.method) {
case 'getSourceCode':
fetchText(url)
.then(text => {
sourceCode = sourceCode || text;
port.postMessage({
method: msg.method + 'Response',
sourceCode,
});
})
.catch(err => port.postMessage({
method: msg.method + 'Response',
error: err.message || String(err),
}));
break;
case 'liveReloadStart':
start();
break;
case 'liveReloadStop':
stop();
break;
}
}
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 start() {
timer = timer || setTimeout(check, DELAY);
}
function stop() {
clearTimeout(timer);
timer = null;
}
function check() {
fetchText(url)
.then(text => {
if (sourceCode === text) return;
sourceCode = text;
port.postMessage({method: 'sourceCodeChanged', sourceCode});
})
.catch(error => {
console.log(chrome.i18n.getMessage('liveReloadError', error));
})
.then(() => {
timer = null;
start();
});
}
function orphanCheck() {
const eventName = chrome.runtime.id + '-install-hook-usercss';
const orphanCheckRequest = () => {
if (chrome.i18n && chrome.i18n.getUILanguage()) return true;
// In Chrome content script is orphaned on an extension update/reload
// so we need to detach event listeners
removeEventListener(eventName, orphanCheckRequest, true);
try {
chrome.runtime.onConnect.removeListener(onConnected);
} catch (e) {}
};
dispatchEvent(new Event(eventName));
addEventListener(eventName, orphanCheckRequest, true);
}
})();