service worker: Wait for inflight requests before activating

content/browser/service_worker/service_worker_registration.cc

Index: content/browser/service_worker/service_worker_registration.cc
diff --git a/content/browser/service_worker/service_worker_registration.cc b/content/browser/service_worker/service_worker_registration.cc
index cfd1e5e6e0d9554e6d069da150e3b52d4c66c3bd..a31feb46daea8b51f105d4cfa0f3bd9a01ad4846 100644
--- a/content/browser/service_worker/service_worker_registration.cc
+++ b/content/browser/service_worker/service_worker_registration.cc
@@ -107,10 +107,11 @@ ServiceWorkerRegistrationInfo ServiceWorkerRegistration::GetInfo() {
 
 void ServiceWorkerRegistration::SetActiveVersion(
     const scoped_refptr<ServiceWorkerVersion>& version) {
-  should_activate_when_ready_ = false;
   if (active_version_ == version)

[nhiroki, 2016/07/13 04:29:30]

(This comment is not related to this CL. You don't have to work on this in this
CL)

I suspect this condition is never satisfied. In production, SetActiveVersion()
can be called from ServiceWorkerStorage::GetOrCreateRegistration() or
ServiceWorkerRegistration::ActivateWaitingVersion(). On the former callsite, a
registration is newly created and its |active_version_| should always be
nullptr. On the latter callsite, it would be strange if |activating_version| is
equal to |exiting_version|.

If these are true, we could replace this if-statement with
DCHECK_NE(active_version_, version) etc.

[falken, 2016/07/14 13:52:07]

Acknowledged. (OTOH, it may be reasonable to write complex setters like this to
be idempotent, even if current code doesn't use them that way.)

     return;
 
+  should_activate_when_ready_ = false;
+
   ChangedVersionAttributesMask mask;
   if (version)
     UnsetVersionInternal(version.get(), &mask);
@@ -126,10 +127,11 @@ void ServiceWorkerRegistration::SetActiveVersion(
 
 void ServiceWorkerRegistration::SetWaitingVersion(
     const scoped_refptr<ServiceWorkerVersion>& version) {
-  should_activate_when_ready_ = false;
   if (waiting_version_ == version)

[nhiroki, 2016/07/13 04:29:30]

ditto.

     return;
 
+  should_activate_when_ready_ = false;
+
   ChangedVersionAttributesMask mask;
   if (version)
     UnsetVersionInternal(version.get(), &mask);
@@ -171,6 +173,7 @@ void ServiceWorkerRegistration::UnsetVersionInternal(
     mask->add(ChangedVersionAttributesMask::INSTALLING_VERSION);
   } else if (waiting_version_.get() == version) {
     waiting_version_ = NULL;
+    should_activate_when_ready_ = false;
     mask->add(ChangedVersionAttributesMask::WAITING_VERSION);
   } else if (active_version_.get() == version) {
     active_version_->RemoveListener(this);
@@ -182,11 +185,8 @@ void ServiceWorkerRegistration::UnsetVersionInternal(
 void ServiceWorkerRegistration::ActivateWaitingVersionWhenReady() {
   DCHECK(waiting_version());
   should_activate_when_ready_ = true;
-
-  if (!active_version() || !active_version()->HasControllee() ||
-      waiting_version()->skip_waiting()) {
+  if (IsReadyToActivate())
     ActivateWaitingVersion(false);

[kinuko, 2016/07/13 02:28:34]

nit: add '/* delay */' comment

[falken, 2016/07/14 13:52:07]

Done.

-  }
 }
 
 void ServiceWorkerRegistration::ClaimClients() {
@@ -253,15 +253,38 @@ void ServiceWorkerRegistration::OnNoControllees(ServiceWorkerVersion* version) {
   DCHECK_EQ(active_version(), version);
   if (is_uninstalling_)
     Clear();
-  else if (should_activate_when_ready_)
-    ActivateWaitingVersion(true);
+  else if (IsReadyToActivate())
+    ActivateWaitingVersion(true /* delay */);
+}
+
+void ServiceWorkerRegistration::OnNoInflightRequests(
+    ServiceWorkerVersion* version) {
+  if (!context_)
+    return;
+  DCHECK_EQ(active_version(), version);
+  if (IsReadyToActivate())
+    ActivateWaitingVersion(false /* delay */);
+}
+
+bool ServiceWorkerRegistration::IsReadyToActivate() const {
+  if (!should_activate_when_ready_)
+    return false;
+
+  DCHECK(waiting_version());
+  const ServiceWorkerVersion* active = active_version();
+  if (!active)
+    return true;
+  if (!active->HasInflightRequests() &&
+      (!active->HasControllee() || waiting_version()->skip_waiting())) {
+    return true;
+  }
+  return false;
 }
 
 void ServiceWorkerRegistration::ActivateWaitingVersion(bool delay) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK(context_);
-  DCHECK(waiting_version());
-  DCHECK(should_activate_when_ready_);
+  DCHECK(IsReadyToActivate());
   should_activate_when_ready_ = false;
   scoped_refptr<ServiceWorkerVersion> activating_version = waiting_version();
   scoped_refptr<ServiceWorkerVersion> exiting_version = active_version();
@@ -271,8 +294,11 @@ void ServiceWorkerRegistration::ActivateWaitingVersion(bool delay) {
 
   // "5. If exitingWorker is not null,
   if (exiting_version.get()) {
-    // TODO(michaeln): should wait for events to be complete
+    // TODO(falken): Update the quoted spec comments once
+    // https://github.com/slightlyoff/ServiceWorker/issues/916 is codified in
+    // the spec.
     // "1. Wait for exitingWorker to finish handling any in-progress requests."
+    // This is already handled by IsReadyToActivate().
     // "2. Terminate exitingWorker."
     exiting_version->StopWorker(
         base::Bind(&ServiceWorkerUtils::NoOpStatusCallback));