Bug 1856090 - Improve ServiceWorker state propagation. r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D190245

dom/workers/ScriptLoader.cpp

@@ -616,8 +616,22 @@ already_AddRefed<ScriptLoadRequest> WorkerScriptLoader::CreateScriptLoadRequest(
 
   Maybe<ClientInfo> clientInfo = GetGlobal()->GetClientInfo();
 
-  RefPtr<WorkerLoadContext> loadContext =
-      new WorkerLoadContext(kind, clientInfo, this);
+  // (For non-serviceworkers, this variable does not matter, but false best
+  // captures their behavior.)
+  bool onlyExistingCachedResourcesAllowed = false;
+  if (mWorkerRef->Private()->IsServiceWorker()) {
+    // https://w3c.github.io/ServiceWorker/#importscripts step 4:
+    // > 4. If serviceWorker’s state is not "parsed" or "installing":
+    // >    1. Return map[url] if it exists and a network error otherwise.
+    //
+    // So if our state is beyond installing, it's too late to make a request
+    // that would perform a new fetch which would be cached.
+    onlyExistingCachedResourcesAllowed =
+        mWorkerRef->Private()->GetServiceWorkerDescriptor().State() >
+        ServiceWorkerState::Installing;
+  }
+  RefPtr<WorkerLoadContext> loadContext = new WorkerLoadContext(
+      kind, clientInfo, this, onlyExistingCachedResourcesAllowed);
 
   // Create ScriptLoadRequests for this WorkerScriptLoader
   ReferrerPolicy referrerPolicy = mWorkerRef->Private()->GetReferrerPolicy();
@@ -1429,7 +1443,8 @@ nsresult ScriptLoaderRunnable::Run() {
     handle->mRunnable = this;
     WorkerLoadContext* loadContext = handle->GetContext();
     mCacheCreator->AddLoader(MakeNotNull<RefPtr<CacheLoadHandler>>(
-        mWorkerRef, handle, loadContext->IsTopLevel(), mScriptLoader));
+        mWorkerRef, handle, loadContext->IsTopLevel(),
+        loadContext->mOnlyExistingCachedResourcesAllowed, mScriptLoader));
   }
 
   // The worker may have a null principal on first load, but in that case its

dom/workers/loader/CacheLoadHandler.cpp

@@ -237,13 +237,14 @@ void CacheCreator::DeleteCache(nsresult aReason) {
 CacheLoadHandler::CacheLoadHandler(ThreadSafeWorkerRef* aWorkerRef,
                                    ThreadSafeRequestHandle* aRequestHandle,
                                    bool aIsWorkerScript,
+                                   bool aOnlyExistingCachedResourcesAllowed,
                                    WorkerScriptLoader* aLoader)
     : mRequestHandle(aRequestHandle),
       mLoader(aLoader),
       mWorkerRef(aWorkerRef),
       mIsWorkerScript(aIsWorkerScript),
       mFailed(false),
-      mState(aWorkerRef->Private()->GetServiceWorkerDescriptor().State()) {
+      mOnlyExistingCachedResourcesAllowed(aOnlyExistingCachedResourcesAllowed) {
   MOZ_ASSERT(aWorkerRef);
   MOZ_ASSERT(aWorkerRef->Private()->IsServiceWorker());
   mMainThreadEventTarget = aWorkerRef->Private()->MainThreadEventTarget();
@@ -373,9 +374,7 @@ void CacheLoadHandler::ResolvedCallback(JSContext* aCx,
     // storage was probably wiped without removing the service worker
     // registration.  It can also happen for exposed reasons like the
     // service worker script calling importScripts() after install.
-    if (NS_WARN_IF(mIsWorkerScript ||
-                   (mState != ServiceWorkerState::Parsed &&
-                    mState != ServiceWorkerState::Installing))) {
+    if (NS_WARN_IF(mIsWorkerScript || mOnlyExistingCachedResourcesAllowed)) {
       Fail(NS_ERROR_DOM_INVALID_STATE_ERR);
       return;
     }

dom/workers/loader/CacheLoadHandler.h

@@ -82,7 +82,9 @@ class CacheLoadHandler final : public PromiseNativeHandler,
 
   CacheLoadHandler(ThreadSafeWorkerRef* aWorkerRef,
                    ThreadSafeRequestHandle* aRequestHandle,
-                   bool aIsWorkerScript, WorkerScriptLoader* aLoader);
+                   bool aIsWorkerScript,
+                   bool aOnlyExistingCachedResourcesAllowed,
+                   WorkerScriptLoader* aLoader);
 
   void Fail(nsresult aRv);
 
@@ -110,7 +112,7 @@ class CacheLoadHandler final : public PromiseNativeHandler,
   RefPtr<ThreadSafeWorkerRef> mWorkerRef;
   const bool mIsWorkerScript;
   bool mFailed;
-  const ServiceWorkerState mState;
+  bool mOnlyExistingCachedResourcesAllowed;
   nsCOMPtr<nsIInputStreamPump> mPump;
   nsCOMPtr<nsIURI> mBaseURI;
   mozilla::dom::ChannelInfo mChannelInfo;

dom/workers/loader/WorkerLoadContext.cpp

@@ -13,11 +13,14 @@ namespace dom {
 
 WorkerLoadContext::WorkerLoadContext(
     Kind aKind, const Maybe<ClientInfo>& aClientInfo,
-    workerinternals::loader::WorkerScriptLoader* aScriptLoader)
+    workerinternals::loader::WorkerScriptLoader* aScriptLoader,
+    bool aOnlyExistingCachedResourcesAllowed)
     : JS::loader::LoadContextBase(JS::loader::ContextKind::Worker),
       mKind(aKind),
       mClientInfo(aClientInfo),
-      mScriptLoader(aScriptLoader){};
+      mScriptLoader(aScriptLoader),
+      mOnlyExistingCachedResourcesAllowed(
+          aOnlyExistingCachedResourcesAllowed){};
 
 ThreadSafeRequestHandle::ThreadSafeRequestHandle(
     JS::loader::ScriptLoadRequest* aRequest, nsISerialEventTarget* aSyncTarget)

dom/workers/loader/WorkerLoadContext.h

@@ -98,7 +98,8 @@ class WorkerLoadContext : public JS::loader::LoadContextBase {
   };
 
   WorkerLoadContext(Kind aKind, const Maybe<ClientInfo>& aClientInfo,
-                    workerinternals::loader::WorkerScriptLoader* aScriptLoader);
+                    workerinternals::loader::WorkerScriptLoader* aScriptLoader,
+                    bool aOnlyExistingCachedResourcesAllowed);
 
   // Used to detect if the `is top-level` bit is set on a given module.
   bool IsTopLevel() {
@@ -163,6 +164,11 @@ class WorkerLoadContext : public JS::loader::LoadContextBase {
 
   CacheStatus mCacheStatus = Uncached;
 
+  // If the requested script is not currently in the cache, should we initiate
+  // a request to fetch and cache it?  Only ServiceWorkers that are being
+  // installed are allowed to go to the network (and then cache the result).
+  bool mOnlyExistingCachedResourcesAllowed = false;
+
   bool IsAwaitingPromise() const { return bool(mCachePromise); }
 };
 

dom/workers/loader/WorkerModuleLoader.cpp

@@ -50,9 +50,10 @@ already_AddRefed<ModuleLoadRequest> WorkerModuleLoader::CreateStaticImport(
   // See Discussion in https://github.com/w3c/webappsec-csp/issues/336
   Maybe<ClientInfo> clientInfo = GetGlobalObject()->GetClientInfo();
 
-  RefPtr<WorkerLoadContext> loadContext =
-      new WorkerLoadContext(WorkerLoadContext::Kind::StaticImport, clientInfo,
-                            aParent->GetWorkerLoadContext()->mScriptLoader);
+  RefPtr<WorkerLoadContext> loadContext = new WorkerLoadContext(
+      WorkerLoadContext::Kind::StaticImport, clientInfo,
+      aParent->GetWorkerLoadContext()->mScriptLoader,
+      aParent->GetWorkerLoadContext()->mOnlyExistingCachedResourcesAllowed);
   RefPtr<ModuleLoadRequest> request = new ModuleLoadRequest(
       aURI, aParent->ReferrerPolicy(), aParent->mFetchOptions, SRIMetadata(),
       aParent->mURI, loadContext, false, /* is top level */
@@ -91,6 +92,8 @@ already_AddRefed<ModuleLoadRequest> WorkerModuleLoader::CreateDynamicImport(
   }
 
   // Not supported for Service Workers.
+  // https://github.com/w3c/ServiceWorker/issues/1585 covers existing discussion
+  // about potentially supporting use of import().
   if (workerPrivate->IsServiceWorker()) {
     return nullptr;
   }
@@ -123,9 +126,16 @@ already_AddRefed<ModuleLoadRequest> WorkerModuleLoader::CreateDynamicImport(
 
   Maybe<ClientInfo> clientInfo = GetGlobalObject()->GetClientInfo();
 
-  RefPtr<WorkerLoadContext> context =
-      new WorkerLoadContext(WorkerLoadContext::Kind::DynamicImport, clientInfo,
-                            GetCurrentScriptLoader());
+  RefPtr<WorkerLoadContext> context = new WorkerLoadContext(
+      WorkerLoadContext::Kind::DynamicImport, clientInfo,
+      GetCurrentScriptLoader(),
+      // When dynamic import is supported in ServiceWorkers,
+      // the current plan in onlyExistingCachedResourcesAllowed
+      // is that only existing cached resources will be
+      // allowed.  (`import()` will not be used for caching
+      // side effects, but instead a specific method will be
+      // used during installation.)
+      true);
 
   ReferrerPolicy referrerPolicy = workerPrivate->GetReferrerPolicy();
   RefPtr<ModuleLoadRequest> request = new ModuleLoadRequest(