1 files changed, 42 insertions, 32 deletions

diff --git a/data/extensions/jid1-KtlZuoiikVfFew@jetpack/content/externalLicenseChecker.js b/data/extensions/jid1-KtlZuoiikVfFew@jetpack/content/externalLicenseChecker.js
index 600a501..f59eed8 100644
--- a/data/extensions/jid1-KtlZuoiikVfFew@jetpack/content/externalLicenseChecker.js
+++ b/data/extensions/jid1-KtlZuoiikVfFew@jetpack/content/externalLicenseChecker.js
@@ -2,6 +2,7 @@
 * GNU LibreJS - A browser add-on to block nonfree nontrivial JavaScript.
 *
 * Copyright (C) 2018 Giorgio Maone <giorgio@maone.net>
+* Copyright (C) 2022 Yuchen Pei <id@ypei.org>
 *
 * This file is part of GNU LibreJS.
 *
@@ -20,38 +21,42 @@
 */
 "use strict";
 {
-  let licensedScripts = null;
-
-  let fetchWebLabels = async args => {
-    // see https://www.gnu.org/software/librejs/free-your-javascript.html#step3
-    let { map, cache } = args;
-    let link = document.querySelector(`link[rel="jslicense"], link[data-jslicense="1"], a[rel="jslicense"], a[data-jslicense="1"]`);
-    let baseURL = link ? link.href : cache.webLabels && new URL(cache.webLabels.href, document.baseURI);
-    if (baseURL) try {
-      let response = await fetch(baseURL);
+  // Find and fetch the url to the web labels table, and returns the
+  // license info in the table as a map from the script url to
+  // { script: {url, label},
+  //   licenseLinks: [{url, label}],
+  //   sources: [{url, label}] }
+  //   
+  // see https://www.gnu.org/software/librejs/free-your-javascript.html#step3
+  const fetchWebLabels = async args => {
+    const { map, cache } = args;
+    const link = document.querySelector(`link[rel="jslicense"], link[data-jslicense="1"], a[rel="jslicense"], a[data-jslicense="1"]`);
+    const webLabelsUrl = link ? link.href : cache.webLabels && new URL(cache.webLabels.href, document.baseURI);
+    if (webLabelsUrl) try {
+      const response = await fetch(webLabelsUrl);
       if (!response.ok) throw `${response.status} ${response.statusText}`;
-      let doc = new DOMParser().parseFromString(
+      const doc = new DOMParser().parseFromString(
         await response.text(),
-        "text/html"
+        'text/html'
       );
-      let base = doc.querySelector("base");
-      if (base) {
-        base.href = base.href;
-      } else {
-        doc.head.appendChild(doc.createElement("base")).href = baseURL;
+      // Sets the base url to be the url of the weblabel page if it
+      // does not exist.  Otherwise relative links on the weblabels
+      // page will use the base of the current page.
+      if (!doc.querySelector("base")) {
+        doc.head.appendChild(doc.createElement("base")).href = webLabelsUrl;
       }
-      let link = a => ({ url: a.href, label: a.textContent });
-      let firstLink = parent => link(parent.querySelector("a"));
-      let allLinks = parent => Array.prototype.map.call(parent.querySelectorAll("a"), link);
-      for (let row of doc.querySelectorAll("table#jslicense-labels1 > tbody > tr")) {
+      const link = a => ({ url: a.href, label: a.textContent });
+      const firstLink = parent => link(parent.querySelector("a"));
+      const allLinks = parent => Array.prototype.map.call(parent.querySelectorAll("a"), link);
+      for (const row of doc.querySelectorAll("table#jslicense-labels1 > tbody > tr")) {
         try {
-          let cols = row.querySelectorAll("td");
-          let script = firstLink(cols[0]);
-          let licenseLinks = allLinks(cols[1]);
-          let sources = cols[2] ? allLinks(cols[2]) : [];
+          const cols = row.querySelectorAll("td");
+          const script = firstLink(cols[0]);
+          const licenseLinks = allLinks(cols[1]);
+          const sources = cols[2] ? allLinks(cols[2]) : [];
           map.set(script.url, { script, licenseLinks, sources });
         } catch (e) {
-          console.error("LibreJS: error parsing Web Labels at %s, row %s", baseURL, row.innerHTML, e);
+          console.error("LibreJS: error parsing Web Labels at %s, row %s", webLabelsUrl, row.innerHTML, e);
         }
       }
     } catch (e) {
@@ -60,9 +65,9 @@
     return map;
   }
 
-  let fetchLicenseInfo = async cache => {
-    let map = new Map();
-    let args = { map, cache };
+  const fetchLicenseInfo = async cache => {
+    const map = new Map();
+    const args = { map, cache };
     // in the fetchXxx methods we add to a map whatever license(s)
     // URLs and source code references we can find in various formats
     // (WebLabels is currently the only implementation), keyed by script URLs.
@@ -75,10 +80,15 @@
     return map;
   }
 
-  let handlers = {
+  const handlers = {
+    // Look up the script url in the web labels and return it if found,
+    //  otherwise return undefined.  The found value is of the format
+    // { script: {url, label},
+    //   licenseLinks: [{url, label}],
+    //   sources: [{url, label}] }
     async checkLicensedScript(m) {
-      let { url, cache } = m;
-      if (!licensedScripts) licensedScripts = await fetchLicenseInfo(cache);
+      const { url, cache } = m;
+      const licensedScripts = await fetchLicenseInfo(cache);
       return licensedScripts.get(url) || licensedScripts.get(url.replace(/\?.*/, ''));
     }
   }
@@ -86,7 +96,7 @@
   browser.runtime.onMessage.addListener(async m => {
     if (m.action in handlers) try {
       debug("Received message", m);
-      let result = await handlers[m.action](m);
+      const result = await handlers[m.action](m);
       return result;
     } catch (e) {
       console.error(e);