Bug 1212333 - WorkerDebuggerManager should live on the main thread;r=khuey

dom/workers/RuntimeService.cpp

@@ -1974,12 +1974,6 @@ RuntimeService::Shutdown()
   // That's it, no more workers.
   mShuttingDown = true;
 
-  // Remove all listeners from the worker debugger manager to ensure that it
-  // gets properly destroyed.
-  if (NS_FAILED(ClearWorkerDebuggerManagerListeners())) {
-    NS_WARNING("Failed to clear worker debugger manager listeners!");
-  }
-
   nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
   NS_WARN_IF_FALSE(obs, "Failed to get observer service?!");
 

dom/workers/WorkerDebuggerManager.cpp

@@ -8,22 +8,23 @@
 
 #include "nsISimpleEnumerator.h"
 
+#include "mozilla/ClearOnShutdown.h"
+
 #include "WorkerPrivate.h"
 
 USING_WORKERS_NAMESPACE
 
+namespace {
+
 class RegisterDebuggerMainThreadRunnable final : public nsRunnable
 {
-  RefPtr<WorkerDebuggerManager> mManager;
   WorkerPrivate* mWorkerPrivate;
   bool mNotifyListeners;
 
 public:
-  RegisterDebuggerMainThreadRunnable(WorkerDebuggerManager* aManager,
-                                     WorkerPrivate* aWorkerPrivate,
+  RegisterDebuggerMainThreadRunnable(WorkerPrivate* aWorkerPrivate,
                                      bool aNotifyListeners)
-  : mManager(aManager),
-    mWorkerPrivate(aWorkerPrivate),
+  : mWorkerPrivate(aWorkerPrivate),
     mNotifyListeners(aNotifyListeners)
   { }
 
@@ -34,21 +35,21 @@ private:
   NS_IMETHOD
   Run() override
   {
-    mManager->RegisterDebuggerMainThread(mWorkerPrivate, mNotifyListeners);
+    WorkerDebuggerManager* manager = WorkerDebuggerManager::Get();
+    MOZ_ASSERT(manager);
 
+    manager->RegisterDebuggerMainThread(mWorkerPrivate, mNotifyListeners);
     return NS_OK;
   }
 };
 
 class UnregisterDebuggerMainThreadRunnable final : public nsRunnable
 {
-  RefPtr<WorkerDebuggerManager> mManager;
   WorkerPrivate* mWorkerPrivate;
 
 public:
-  UnregisterDebuggerMainThreadRunnable(WorkerDebuggerManager* aManager,
-                                       WorkerPrivate* aWorkerPrivate)
-  : mManager(aManager), mWorkerPrivate(aWorkerPrivate)
+  explicit UnregisterDebuggerMainThreadRunnable(WorkerPrivate* aWorkerPrivate)
+  : mWorkerPrivate(aWorkerPrivate)
   { }
 
 private:
@@ -58,12 +59,19 @@ private:
   NS_IMETHOD
   Run() override
   {
-    mManager->UnregisterDebuggerMainThread(mWorkerPrivate);
+    WorkerDebuggerManager* manager = WorkerDebuggerManager::Get();
+    MOZ_ASSERT(manager);
 
+    manager->UnregisterDebuggerMainThread(mWorkerPrivate);
     return NS_OK;
   }
 };
 
+// Does not hold an owning reference.
+static WorkerDebuggerManager* gWorkerDebuggerManager;
+
+} /* anonymous namespace */
+
 BEGIN_WORKERS_NAMESPACE
 
 class WorkerDebuggerEnumerator final : public nsISimpleEnumerator
@@ -116,7 +124,54 @@ WorkerDebuggerManager::~WorkerDebuggerManager()
   AssertIsOnMainThread();
 }
 
-NS_IMPL_ISUPPORTS(WorkerDebuggerManager, nsIWorkerDebuggerManager);
+// static
+already_AddRefed<WorkerDebuggerManager>
+WorkerDebuggerManager::GetInstance()
+{
+  RefPtr<WorkerDebuggerManager> manager = WorkerDebuggerManager::GetOrCreate();
+  return manager.forget();
+}
+
+// static
+WorkerDebuggerManager*
+WorkerDebuggerManager::GetOrCreate()
+{
+  AssertIsOnMainThread();
+
+  if (!gWorkerDebuggerManager) {
+    // The observer service now owns us until shutdown.
+    gWorkerDebuggerManager = new WorkerDebuggerManager();
+    if (NS_FAILED(gWorkerDebuggerManager->Init())) {
+      NS_WARNING("Failed to initialize worker debugger manager!");
+      gWorkerDebuggerManager = nullptr;
+      return nullptr;
+    }
+  }
+
+  return gWorkerDebuggerManager;
+}
+
+WorkerDebuggerManager*
+WorkerDebuggerManager::Get()
+{
+  MOZ_ASSERT(gWorkerDebuggerManager);
+  return gWorkerDebuggerManager;
+}
+
+NS_IMPL_ISUPPORTS(WorkerDebuggerManager, nsIObserver, nsIWorkerDebuggerManager);
+
+NS_IMETHODIMP
+WorkerDebuggerManager::Observe(nsISupports* aSubject, const char* aTopic,
+                               const char16_t* aData)
+{
+  if (!strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID)) {
+    Shutdown();
+    return NS_OK;
+  }
+
+  NS_NOTREACHED("Unknown observer topic!");
+  return NS_OK;
+}
 
 NS_IMETHODIMP
 WorkerDebuggerManager::GetWorkerDebuggerEnumerator(
@@ -161,8 +216,20 @@ WorkerDebuggerManager::RemoveListener(
   return NS_OK;
 }
 
+nsresult
+WorkerDebuggerManager::Init()
+{
+  nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
+  NS_ENSURE_TRUE(obs, NS_ERROR_FAILURE);
+
+  nsresult rv = obs->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
 void
-WorkerDebuggerManager::ClearListeners()
+WorkerDebuggerManager::Shutdown()
 {
   AssertIsOnMainThread();
 
@@ -205,8 +272,7 @@ WorkerDebuggerManager::RegisterDebugger(WorkerPrivate* aWorkerPrivate)
     }
 
     nsCOMPtr<nsIRunnable> runnable =
-      new RegisterDebuggerMainThreadRunnable(this, aWorkerPrivate,
-                                             hasListeners);
+      new RegisterDebuggerMainThreadRunnable(aWorkerPrivate, hasListeners);
     MOZ_ALWAYS_TRUE(NS_SUCCEEDED(
       NS_DispatchToMainThread(runnable, NS_DISPATCH_NORMAL)));
 
@@ -225,7 +291,7 @@ WorkerDebuggerManager::UnregisterDebugger(WorkerPrivate* aWorkerPrivate)
     UnregisterDebuggerMainThread(aWorkerPrivate);
   } else {
     nsCOMPtr<nsIRunnable> runnable =
-      new UnregisterDebuggerMainThreadRunnable(this, aWorkerPrivate);
+      new UnregisterDebuggerMainThreadRunnable(aWorkerPrivate);
     MOZ_ALWAYS_TRUE(NS_SUCCEEDED(
       NS_DispatchToMainThread(runnable, NS_DISPATCH_NORMAL)));
 

dom/workers/WorkerDebuggerManager.h

@@ -9,6 +9,7 @@
 
 #include "Workers.h"
 
+#include "nsIObserver.h"
 #include "nsIWorkerDebuggerManager.h"
 
 #include "nsServiceManagerUtils.h"
@@ -24,7 +25,8 @@ BEGIN_WORKERS_NAMESPACE
 
 class WorkerDebugger;
 
-class WorkerDebuggerManager final : public nsIWorkerDebuggerManager
+class WorkerDebuggerManager final : public nsIObserver,
+                                    public nsIWorkerDebuggerManager
 {
   Mutex mMutex;
 
@@ -35,54 +37,58 @@ class WorkerDebuggerManager final : public nsIWorkerDebuggerManager
   nsTArray<RefPtr<WorkerDebugger>> mDebuggers;
 
 public:
+  static already_AddRefed<WorkerDebuggerManager>
+  GetInstance();
+
   static WorkerDebuggerManager*
-  GetOrCreateService()
-  {
-    nsCOMPtr<nsIWorkerDebuggerManager> manager =
-      do_GetService(WORKERDEBUGGERMANAGER_CONTRACTID);
-    return static_cast<WorkerDebuggerManager*>(manager.get());
-  }
+  GetOrCreate();
+
+  static WorkerDebuggerManager*
+  Get();
 
   WorkerDebuggerManager();
 
-  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
   NS_DECL_NSIWORKERDEBUGGERMANAGER
 
-  void ClearListeners();
+  nsresult
+  Init();
 
-  void RegisterDebugger(WorkerPrivate* aWorkerPrivate);
+  void
+  Shutdown();
 
-  void UnregisterDebugger(WorkerPrivate* aWorkerPrivate);
+  void
+  RegisterDebugger(WorkerPrivate* aWorkerPrivate);
 
-  void RegisterDebuggerMainThread(WorkerPrivate* aWorkerPrivate,
-                                  bool aNotifyListeners);
+  void
+  RegisterDebuggerMainThread(WorkerPrivate* aWorkerPrivate,
+                             bool aNotifyListeners);
 
-  void UnregisterDebuggerMainThread(WorkerPrivate* aWorkerPrivate);
+  void
+  UnregisterDebugger(WorkerPrivate* aWorkerPrivate);
+
+  void
+  UnregisterDebuggerMainThread(WorkerPrivate* aWorkerPrivate);
 
 private:
   virtual ~WorkerDebuggerManager();
 };
 
-inline nsresult
-ClearWorkerDebuggerManagerListeners()
-{
-  RefPtr<WorkerDebuggerManager> manager =
-    WorkerDebuggerManager::GetOrCreateService();
-  if (!manager) {
-    return NS_ERROR_FAILURE;
-  }
-
-  manager->ClearListeners();
-  return NS_OK;
-}
-
 inline nsresult
 RegisterWorkerDebugger(WorkerPrivate* aWorkerPrivate)
 {
-  RefPtr<WorkerDebuggerManager> manager =
-    WorkerDebuggerManager::GetOrCreateService();
-  if (!manager) {
-    return NS_ERROR_FAILURE;
+  WorkerDebuggerManager* manager;
+
+  if (NS_IsMainThread()) {
+    manager = WorkerDebuggerManager::GetOrCreate();
+    if (!manager) {
+      NS_WARNING("Failed to create worker debugger manager!");
+      return NS_ERROR_FAILURE;
+    }
+  }
+  else {
+    manager = WorkerDebuggerManager::Get();
   }
 
   manager->RegisterDebugger(aWorkerPrivate);
@@ -92,10 +98,17 @@ RegisterWorkerDebugger(WorkerPrivate* aWorkerPrivate)
 inline nsresult
 UnregisterWorkerDebugger(WorkerPrivate* aWorkerPrivate)
 {
-  RefPtr<WorkerDebuggerManager> manager =
-    WorkerDebuggerManager::GetOrCreateService();
-  if (!manager) {
-    return NS_ERROR_FAILURE;
+  WorkerDebuggerManager* manager;
+
+  if (NS_IsMainThread()) {
+    manager = WorkerDebuggerManager::GetOrCreate();
+    if (!manager) {
+      NS_WARNING("Failed to create worker debugger manager!");
+      return NS_ERROR_FAILURE;
+    }
+  }
+  else {
+    manager = WorkerDebuggerManager::Get();
   }
 
   manager->UnregisterDebugger(aWorkerPrivate);

layout/build/nsLayoutModule.cpp

@@ -322,7 +322,8 @@ NS_GENERIC_FACTORY_SINGLETON_CONSTRUCTOR(QuotaManagerService,
                                          QuotaManagerService::FactoryCreate)
 NS_GENERIC_FACTORY_SINGLETON_CONSTRUCTOR(ServiceWorkerManager,
                                          ServiceWorkerManager::GetInstance)
-NS_GENERIC_FACTORY_CONSTRUCTOR(WorkerDebuggerManager)
+NS_GENERIC_FACTORY_SINGLETON_CONSTRUCTOR(WorkerDebuggerManager,
+                                         WorkerDebuggerManager::GetInstance)
 
 #ifdef MOZ_WIDGET_GONK
 NS_GENERIC_FACTORY_SINGLETON_CONSTRUCTOR(SystemWorkerManager,