Support pane: mark lists as obsolete only when update button is clicked

Lists older than 2 hours were unconditionally marked as obsolete when
opening the _Support_ pane. Those lists will now be marked as obsolete
only when the _Update now_ button in the _Support_ pane is pressed, i.e.
when launching an update cycle.

Related discussion:
uBlockOrigin/uBlock-discussions#781 (comment)

src/css/support.css

@@ -54,12 +54,12 @@ body.filterIssue #moreButton {
     display: none;
 }
 
-body.shouldUpdate:not(.updated) .e .createEntry {
+body[data-should-update-lists]:not(.updated) .e .createEntry {
     opacity: 0.25;
     pointer-events: none;
 }
 
-body:not(.shouldUpdate) .shouldUpdate {
+body:not([data-should-update-lists]) .shouldUpdate {
     display: none;
     }
 body.updating {

src/js/messaging.js

@@ -602,11 +602,10 @@ const launchReporter = async function(request) {
     const entries = await io.getUpdateAges({
         filters: µb.selectedFilterLists.slice()
     });
-    let shouldUpdateLists = false;
+    const shouldUpdateLists = [];
     for ( const entry of entries ) {
         if ( entry.age < (2 * 60 * 60 * 1000) ) { continue; }
-        io.purge(entry.assetKey);
-        shouldUpdateLists = true;
+        shouldUpdateLists.push(entry.assetKey);
     }
 
     // https://github.com/gorhill/uBlock/commit/6efd8eb#commitcomment-107523558
@@ -634,8 +633,8 @@ const launchReporter = async function(request) {
     const supportURL = new URL(vAPI.getURL('support.html'));
     supportURL.searchParams.set('pageURL', request.pageURL);
     supportURL.searchParams.set('popupPanel', JSON.stringify(request.popupPanel));
-    if ( shouldUpdateLists ) {
-        supportURL.searchParams.set('shouldUpdate', 1);
+    if ( shouldUpdateLists.length ) {
+        supportURL.searchParams.set('shouldUpdateLists', JSON.stringify(shouldUpdateLists));
     }
     return supportURL.href;
 };

src/js/support.js

@@ -210,8 +210,9 @@ const reportedPage = (( ) => {
             dom.text(option, parsedURL.href);
             select.append(option);
         }
-        if ( url.searchParams.get('shouldUpdate') !== null ) {
-            dom.cl.add(dom.body, 'shouldUpdate');
+        const shouldUpdateLists = url.searchParams.get('shouldUpdateLists');
+        if ( shouldUpdateLists !== null ) {
+            dom.body.dataset.shouldUpdateLists = shouldUpdateLists;
         }
         dom.cl.add(dom.body, 'filterIssue');
         return {
@@ -250,8 +251,12 @@ function reportSpecificFilterIssue() {
 }
 
 async function updateFilterLists() {
+    if ( dom.body.dataset.shouldUpdateLists === undefined ) { return false; }
     dom.cl.add(dom.body, 'updating');
+    const assetKeys = JSON.parse(dom.body.dataset.shouldUpdateLists);
+    vAPI.messaging.send('dashboard', { what: 'purgeCaches', assetKeys });
     vAPI.messaging.send('dashboard', { what: 'forceUpdateAssets' });
+    return true;
 }
 
 /******************************************************************************/
@@ -281,9 +286,9 @@ uBlockDashboard.patchCodeMirrorEditor(cmEditor);
     });
 
     if ( reportedPage !== null ) {
-        if ( dom.cl.has(dom.body, 'shouldUpdate') ) {
+        if ( dom.body.dataset.shouldUpdateLists ) {
             dom.on('.supportEntry.shouldUpdate button', 'click', ev => {
-                updateFilterLists();
+                if ( updateFilterLists() === false ) { return; }
                 ev.preventDefault();
             });
         }