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..64aba5869f0024fc4314cdf04caf3a4e94f402f4 100644
--- a/content/browser/service_worker/service_worker_registration.cc
+++ b/content/browser/service_worker/service_worker_registration.cc
@@ -182,11 +182,8 @@ 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);
-  }
 }
 
 void ServiceWorkerRegistration::ClaimClients() {
@@ -253,8 +250,27 @@ 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 {

[nhiroki, 2016/07/08 05:04:42]

DCHECK(waiting_version()) ?

[falken, 2016/07/08 07:06:45]

Hmm good catch. The code assumes should_activate_when_ready_ is only true if
there is a waiting_version, but I think thanks to DeleteVersion that's not true.
Updated.

+  if (!should_activate_when_ready_)
+    return false;
+
+  const ServiceWorkerVersion* active = active_version();
+  return !(active &&
+           (active->HasInflightRequests() ||
+            (active->HasControllee() && !waiting_version()->skip_waiting())));

[nhiroki, 2016/07/08 05:04:42]

Negating the whole complex expression would make it difficult to read. How about
deforming it with De Morgan's laws like this?

   !(active && (HasInflight || (HasControllee && !skip_waiting)))
-> !active || !(HasInflight || (HasControllee && !skip_waiting))
-> !active || (!HasInflight && !(HasControllee && !skip_waiting))
-> !active || (!HasInflight && (!HasControllee || skip_waiting))

if (!active)
  return true;
if (!active->HasInflightRequests() &&
    (!HasControllee || waiting_version()->skip_waiting()))
  return true;
return false;

[falken, 2016/07/08 07:06:45]

Done.

 }
 
 void ServiceWorkerRegistration::ActivateWaitingVersion(bool delay) {
@@ -271,8 +287,11 @@ 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));