Service Worker: in Unregister, wait until after the active worker no longer controls a document

content/browser/service_worker/service_worker_registration.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/service_worker/service_worker_registration.h"
 
 #include "content/browser/service_worker/service_worker_context_core.h"
 #include "content/browser/service_worker/service_worker_info.h"
 #include "content/browser/service_worker/service_worker_register_job.h"
 #include "content/browser/service_worker/service_worker_utils.h"
@@ skipping 13 matching lines @@
 
 ServiceWorkerRegistration::ServiceWorkerRegistration(
     const GURL& pattern,
     const GURL& script_url,
     int64 registration_id,
     base::WeakPtr<ServiceWorkerContextCore> context)
     : pattern_(pattern),
       script_url_(script_url),
       registration_id_(registration_id),
       is_deleted_(false),
+      is_uninstalling_(false),
       should_activate_when_ready_(false),
       context_(context) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   DCHECK(context_);
   context_->AddLiveRegistration(this);
 }
 
 ServiceWorkerRegistration::~ServiceWorkerRegistration() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   DCHECK(!listeners_.might_have_observers());
   if (context_)
     context_->RemoveLiveRegistration(registration_id_);
-  ResetShouldActivateWhenReady();
+  if (active_version())
+    active_version()->RemoveListener(this);
 }
 
 void ServiceWorkerRegistration::AddListener(Listener* listener) {
   listeners_.AddObserver(listener);
 }
 
 void ServiceWorkerRegistration::RemoveListener(Listener* listener) {
   listeners_.RemoveObserver(listener);
 }
 
 void ServiceWorkerRegistration::NotifyRegistrationFailed() {
   FOR_EACH_OBSERVER(Listener, listeners_, OnRegistrationFailed(this));
 }
 
 ServiceWorkerRegistrationInfo ServiceWorkerRegistration::GetInfo() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   return ServiceWorkerRegistrationInfo(
       script_url(),
       pattern(),
       registration_id_,
       GetVersionInfo(active_version_),
       GetVersionInfo(waiting_version_),
       GetVersionInfo(installing_version_));
 }
 
 void ServiceWorkerRegistration::SetActiveVersion(
     ServiceWorkerVersion* version) {
-  ResetShouldActivateWhenReady();
+  should_activate_when_ready_ = false;
   SetVersionInternal(version, &active_version_,
                      ChangedVersionAttributesMask::ACTIVE_VERSION);
 }
 
 void ServiceWorkerRegistration::SetWaitingVersion(
     ServiceWorkerVersion* version) {
-  ResetShouldActivateWhenReady();
+  should_activate_when_ready_ = false;
   SetVersionInternal(version, &waiting_version_,
                      ChangedVersionAttributesMask::WAITING_VERSION);
 }
 
 void ServiceWorkerRegistration::SetInstallingVersion(
     ServiceWorkerVersion* version) {
   SetVersionInternal(version, &installing_version_,
                      ChangedVersionAttributesMask::INSTALLING_VERSION);
 }
 
@@ skipping 13 matching lines @@
     ServiceWorkerVersion* version,
     scoped_refptr<ServiceWorkerVersion>* data_member,
     int change_flag) {
   if (version == data_member->get())
     return;
   scoped_refptr<ServiceWorkerVersion> protect(version);
   ChangedVersionAttributesMask mask;
   if (version)
     UnsetVersionInternal(version, &mask);
   *data_member = version;
+  if (active_version_ && active_version_ == version)
+    active_version_->AddListener(this);
   mask.add(change_flag);
   ServiceWorkerRegistrationInfo info = GetInfo();
   FOR_EACH_OBSERVER(Listener, listeners_,
                     OnVersionAttributesChanged(this, mask, info));
 }
 
 void ServiceWorkerRegistration::UnsetVersionInternal(
     ServiceWorkerVersion* version,
     ChangedVersionAttributesMask* mask) {
   DCHECK(version);
   if (installing_version_ == version) {
     installing_version_ = NULL;
     mask->add(ChangedVersionAttributesMask::INSTALLING_VERSION);
   } else if (waiting_version_  == version) {
     waiting_version_ = NULL;
     mask->add(ChangedVersionAttributesMask::WAITING_VERSION);
   } else if (active_version_ == version) {
+    active_version_->RemoveListener(this);
     active_version_ = NULL;
     mask->add(ChangedVersionAttributesMask::ACTIVE_VERSION);
   }
 }
 
 void ServiceWorkerRegistration::ActivateWaitingVersionWhenReady() {
   DCHECK(waiting_version());
-  if (should_activate_when_ready_)
+  should_activate_when_ready_ = true;
+  if (!active_version() || !active_version()->HasControllee())
+    ActivateWaitingVersion();
+}
+
+void ServiceWorkerRegistration::ClearWhenReady() {
+  DCHECK(context_);
+  if (is_uninstalling_)
     return;
-  if (active_version() && active_version()->HasControllee()) {
-    active_version()->AddListener(this);
-    should_activate_when_ready_ = true;
+  is_uninstalling_ = true;
+
+  context_->storage()->NotifyUninstallingRegistration(this);
+  context_->storage()->DeleteRegistration(
+      id(),
+      script_url().GetOrigin(),
+      base::Bind(&ServiceWorkerUtils::NoOpStatusCallback));
+
+  if (!active_version() || !active_version()->HasControllee())
+    Clear();
+}
+
+void ServiceWorkerRegistration::AbortPendingClear() {
+  DCHECK(context_);
+  if (!is_uninstalling())
     return;
-  }
-  ActivateWaitingVersion();
+  is_uninstalling_ = false;
+  context_->storage()->NotifyDoneUninstallingRegistration(this);
+
+  scoped_refptr<ServiceWorkerVersion> most_recent_version =
+      waiting_version() ? waiting_version() : active_version();
+  DCHECK(most_recent_version);

[falken, 2014/08/12 09:06:06]

My earlier patches handled the case where there is no waiting or active version.
But I think that's an impossible case. The only window for waiting/active to
change is from the end of an unregister() and the beginning of a register() for
the same-scope. Since only RegisterJob mutates waiting/active, I don't expect
them to be cleared.

If code changes someday, the DCHECK will trip and we can deal with it then. I
don't want to add code to handle an impossible condition because it's a deep
rabbit hole (should we set is_deleted_ to false? what about 'installing'? etc)

+  context_->storage()->NotifyInstallingRegistration(this);
+  context_->storage()->StoreRegistration(
+      this,
+      most_recent_version,
+      base::Bind(&ServiceWorkerRegistration::OnStoreFinished,
+                 this,
+                 most_recent_version));
 }
 
 void ServiceWorkerRegistration::OnNoControllees(ServiceWorkerVersion* version) {
   DCHECK_EQ(active_version(), version);
-  DCHECK(should_activate_when_ready_);
-  active_version_->RemoveListener(this);
+  if (is_uninstalling_)
+    Clear();
+  else if (should_activate_when_ready_)
+    ActivateWaitingVersion();
+  is_uninstalling_ = false;
   should_activate_when_ready_ = false;
-  ActivateWaitingVersion();
 }
 
 void ServiceWorkerRegistration::ActivateWaitingVersion() {
   DCHECK(context_);
   DCHECK(waiting_version());
+  DCHECK(should_activate_when_ready_);
+  should_activate_when_ready_ = false;
   scoped_refptr<ServiceWorkerVersion> activating_version = waiting_version();
   scoped_refptr<ServiceWorkerVersion> exiting_version = active_version();
 
   if (activating_version->is_doomed() ||
       activating_version->status() == ServiceWorkerVersion::REDUNDANT) {
     return;  // Activation is no longer relevant.
   }
 
   // "4. If exitingWorker is not null,
   if (exiting_version) {
@@ skipping 50 matching lines @@
   // "12. Run the [[UpdateState]] algorithm passing registration.activeWorker
   // and "activated" as the arguments."
   activating_version->SetStatus(ServiceWorkerVersion::ACTIVATED);
   if (context_) {
     context_->storage()->UpdateToActiveState(
         this,
         base::Bind(&ServiceWorkerUtils::NoOpStatusCallback));
   }
 }
 
-void ServiceWorkerRegistration::ResetShouldActivateWhenReady() {
-  if (should_activate_when_ready_) {
-    active_version()->RemoveListener(this);
-    should_activate_when_ready_ = false;
-  }
-}
-
 void ServiceWorkerRegistration::OnDeleteFinished(
     ServiceWorkerStatusCode status) {
   // Intentionally empty completion callback, used to prevent
   // |this| from being deleted until the storage method completes.
 }
 
+void ServiceWorkerRegistration::Clear() {
+  context_->storage()->NotifyDoneUninstallingRegistration(this);
+
+  if (installing_version()) {
+    installing_version()->Doom();
+    UnsetVersion(installing_version());
+  }
+
+  if (waiting_version()) {
+    waiting_version()->Doom();
+    UnsetVersion(waiting_version());
+  }
+
+  if (active_version()) {
+    active_version()->Doom();
+    UnsetVersion(active_version());
+  }
+}
+
+void ServiceWorkerRegistration::OnStoreFinished(
+    scoped_refptr<ServiceWorkerVersion> version,
+    ServiceWorkerStatusCode status) {
+  if (!context_)
+    return;
+  context_->storage()->NotifyDoneInstallingRegistration(
+      this, version.get(), status);
+}
+
 }  // namespace content