Synchronize verified assets incrementally and guard update activation

frontend/sw-update.js

@@ -64,7 +64,7 @@
    * @param {Function} [opts.setTimeout]
    * @returns {Promise<{refreshed: number, caches: number, resumed: number}>}
    */
-  async function refreshShellInPlace({ cachesApi, fetchFn, isShellCache, bust, timeoutMs, attempts, attemptTimeoutMs, concurrency, stagingKey, setTimeout: setTimeoutFn }) {
+  async function refreshLegacyShell({ cachesApi, fetchFn, isShellCache, bust, timeoutMs, attempts, attemptTimeoutMs, concurrency, stagingKey, setTimeout: setTimeoutFn }) {
     const names = (await cachesApi.keys()).filter(isShellCache);
     if (!names.length) return { refreshed: 0, caches: 0, resumed: 0 }; // uncontrolled page: a reload already hits the network
 
@@ -145,6 +145,42 @@
     return { refreshed: urls.size, caches: names.length, resumed };
   }
 
+  async function refreshShellInPlace(opts) {
+    const core = root.AssetSyncCore;
+    if (core) {
+      const response = await opts.fetchFn('/api/manifest', { cache: 'no-store' });
+      if (!response.ok) throw new Error('Manifest unavailable');
+      const m = await response.json();
+      const cache = await opts.cachesApi.open(core.CACHE);
+      // Only upgraded workers can route the persistent scheme. A rollback
+      // worker explicitly advertises the legacy path through CACHE_STATUS.
+      const reg = root.navigator && await root.navigator.serviceWorker.getRegistration();
+      const worker = reg && (reg.waiting || reg.active);
+      const status = await askCacheStatus(worker);
+      if (status && status.assetSync) {
+        const result = await core.syncAssets(m,{cache,fetchFn:opts.fetchFn});
+        if (!reg.waiting) await core.commit(m,cache);
+        return result;
+      }
+    }
+    return refreshLegacyShell({ ...opts, isShellCache: n => n !== 'ytplayer-assets' && opts.isShellCache(n) });
+  }
+
+  function playing() { return typeof Player !== 'undefined' && !!Player._wantsPlaying; }
+  function reportPlaying(value = playing()) {
+    const sw = root.navigator && root.navigator.serviceWorker;
+    if (!sw) return;
+    sw.getRegistration().then(reg => {
+      for (const worker of [sw.controller, reg && reg.waiting]) if(worker) worker.postMessage({type:'PLAYING',value});
+    }).catch(()=>{});
+  }
+  if (root.document && root.navigator && root.navigator.serviceWorker) {
+    if (root.VisibleTimer) root.VisibleTimer.setIntervalWhenVisible(()=>reportPlaying(),1000);
+    for (const event of ['play','pause','ended']) root.document.addEventListener(event,()=>reportPlaying(),true);
+    root.document.addEventListener('visibilitychange',()=>reportPlaying());
+    root.navigator.serviceWorker.addEventListener('controllerchange',()=>reportPlaying());
+  }
+
   /**
    * Asks a worker whether it has already precached its whole shell.
    * Resolves to null on any problem (no reply, no MessageChannel, timeout) —
@@ -191,7 +227,14 @@
    * @param {Function} [opts.setTimeout]                injectable for tests
    * @returns {Promise<void>}
    */
-  async function applyUpdate({ reg, container, reload, refreshShell, askStatus, onPhase, setTimeout: setTimeoutFn }) {
+  async function applyUpdate({ reg, container, reload, refreshShell, askStatus, onPhase, isPlaying = playing, confirmOverride = root.confirm && root.confirm.bind(root), setTimeout: setTimeoutFn }) {
+    let overridden = false;
+    const guard = () => {
+      if (!isPlaying() || overridden) return true;
+      if (confirmOverride && confirmOverride('Playing - update after this song / when paused. Update now anyway? Playback may stop.')) { overridden = true; return true; }
+      return false;
+    };
+    if (!guard()) throw new Error('Playing - update after this song / when paused');
     const scheduleTimeout = setTimeoutFn || (typeof setTimeout !== 'undefined' ? setTimeout : null);
     const waiting = reg && reg.waiting;
 
@@ -209,6 +252,7 @@
     if (onPhase) onPhase(precached ? 'ready' : 'downloading');
     if (!precached && refreshShell) await refreshShell();
 
+    if (!guard()) throw new Error('Playing - update after this song / when paused');
     if (!waiting) {
       reload();
       return;
@@ -216,7 +260,7 @@
 
     let reloaded = false;
     const reloadOnce = () => {
-      if (reloaded) return;
+      if (reloaded || (isPlaying() && !overridden)) return;
       reloaded = true;
       reload();
     };
@@ -224,6 +268,7 @@
     // either way; reload on controllerchange, or after a short safety net.
     container.addEventListener('controllerchange', reloadOnce, { once: true });
     if (scheduleTimeout) scheduleTimeout(reloadOnce, 4000);
+    if (overridden) waiting.postMessage({type:'PLAYING',value:false});
     waiting.postMessage({ type: 'SKIP_WAITING' });
   }