Bug 1237794: Extend ClearOnShutdown() to allow specifying the shutdown phase
--- a/xpcom/base/ClearOnShutdown.cpp
+++ b/xpcom/base/ClearOnShutdown.cpp
@@ -5,12 +5,13 @@
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/ClearOnShutdown.h"
namespace mozilla {
namespace ClearOnShutdown_Internal {
bool sHasShutDown = false;
-StaticAutoPtr<LinkedList<ShutdownObserver>> sShutdownObservers;
+Array<StaticAutoPtr<ShutdownList>,
+ static_cast<size_t>(ShutdownPhase::ShutdownPhase_Length)> sShutdownObservers;
} // namespace ClearOnShutdown_Internal
} // namespace mozilla
--- a/xpcom/base/ClearOnShutdown.h
+++ b/xpcom/base/ClearOnShutdown.h
@@ -4,26 +4,30 @@
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_ClearOnShutdown_h
#define mozilla_ClearOnShutdown_h
#include "mozilla/LinkedList.h"
#include "mozilla/StaticPtr.h"
+#include "mozilla/Array.h"
#include "MainThreadUtils.h"
/*
* This header exports one public method in the mozilla namespace:
*
* template<class SmartPtr>
- * void ClearOnShutdown(SmartPtr *aPtr)
+ * void ClearOnShutdown(SmartPtr *aPtr, aPhase=SHUTDOWN_FINAL)
*
* This function takes a pointer to a smart pointer and nulls the smart pointer
- * on shutdown.
+ * on shutdown (and a particular phase of shutdown as needed). If a phase
+ * is specified, the ptr will be cleared at the start of that phase. Also,
+ * if a phase has already occurred when ClearOnShutdown() is called, the
+ * pointer will be cleared on the next phase, or SHUTDOWN_FINAL.
*
* This is useful if you have a global smart pointer object which you don't
* want to "leak" on shutdown.
*
* Although ClearOnShutdown will work with any smart pointer (i.e., nsCOMPtr,
* nsRefPtr, nsAutoPtr, StaticRefPtr, and StaticAutoPtr), you probably want to
* use it only with StaticRefPtr and StaticAutoPtr. There is no way to undo a
* call to ClearOnShutdown, so you can call it only on smart pointers which you
@@ -31,16 +35,30 @@
* global variables, which should be Static{Ref,Auto}Ptr.
*
* ClearOnShutdown is currently main-thread only because we don't want to
* accidentally free an object from a different thread than the one it was
* created on.
*/
namespace mozilla {
+
+// Must be contiguous starting at 0
+enum class ShutdownPhase {
+ ProfileChange = 0,
+ WillShutdown,
+ Shutdown,
+ ShutdownThreads,
+ ShutdownLoaders,
+ ShutdownFinal,
+ ShutdownPhase_Length, // never pass this value
+ First = ProfileChange, // for iteration
+ Last = ShutdownFinal
+};
+
namespace ClearOnShutdown_Internal {
class ShutdownObserver : public LinkedListElement<ShutdownObserver>
{
public:
virtual void Shutdown() = 0;
virtual ~ShutdownObserver()
{
@@ -63,50 +81,67 @@ public:
}
}
private:
SmartPtr* mPtr;
};
extern bool sHasShutDown;
-extern StaticAutoPtr<LinkedList<ShutdownObserver>> sShutdownObservers;
+typedef LinkedList<ShutdownObserver> ShutdownList;
+extern Array<StaticAutoPtr<ShutdownList>,
+ static_cast<size_t>(ShutdownPhase::ShutdownPhase_Length)> sShutdownObservers;
} // namespace ClearOnShutdown_Internal
template<class SmartPtr>
inline void
-ClearOnShutdown(SmartPtr* aPtr)
+ClearOnShutdown(SmartPtr* aPtr, ShutdownPhase aPhase = ShutdownPhase::ShutdownFinal)
{
using namespace ClearOnShutdown_Internal;
MOZ_ASSERT(NS_IsMainThread());
MOZ_ASSERT(!sHasShutDown);
+ MOZ_ASSERT(aPhase != ShutdownPhase::ShutdownPhase_Length);
- if (!sShutdownObservers) {
- sShutdownObservers = new LinkedList<ShutdownObserver>();
+ if (!(sShutdownObservers[static_cast<size_t>(aPhase)])) {
+ sShutdownObservers[static_cast<size_t>(aPhase)] = new ShutdownList();
}
- sShutdownObservers->insertBack(new PointerClearer<SmartPtr>(aPtr));
+ sShutdownObservers[static_cast<size_t>(aPhase)]->insertBack(new PointerClearer<SmartPtr>(aPtr));
}
// Called when XPCOM is shutting down, after all shutdown notifications have
// been sent and after all threads' event loops have been purged.
inline void
-KillClearOnShutdown()
+KillClearOnShutdown(ShutdownPhase aPhase)
{
using namespace ClearOnShutdown_Internal;
MOZ_ASSERT(NS_IsMainThread());
- if (sShutdownObservers) {
- while (ShutdownObserver* observer = sShutdownObservers->popFirst()) {
- observer->Shutdown();
- delete observer;
+ // Out of caution, when we clear a phase, Verify all "older" phases are cleared in
+ // case something gets re-added to them after we passed that phase.
+ for (size_t phase = static_cast<size_t>(ShutdownPhase::First);
+ phase <= static_cast<size_t>(aPhase);
+ phase++) {
+ if (phase != static_cast<size_t>(aPhase)) {
+ // Because I'm extra paranoid make this assert always
+ MOZ_RELEASE_ASSERT(!sShutdownObservers[static_cast<size_t>(phase)]);
+ } else {
+ if (sShutdownObservers[static_cast<size_t>(phase)]) {
+ while (ShutdownObserver* observer = sShutdownObservers[static_cast<size_t>(phase)]->popFirst()) {
+ observer->Shutdown();
+ delete observer;
+ }
+ sShutdownObservers[static_cast<size_t>(phase)] = nullptr;
+ }
}
}
- sShutdownObservers = nullptr;
- sHasShutDown = true;
+ if (aPhase == ShutdownPhase::ShutdownFinal) {
+ // All must have been cleared here
+ sHasShutDown = true;
+ }
}
} // namespace mozilla
#endif
--- a/xpcom/build/XPCOMInit.cpp
+++ b/xpcom/build/XPCOMInit.cpp
@@ -838,35 +838,38 @@ ShutdownXPCOM(nsIServiceManager* aServMg
return NS_ERROR_UNEXPECTED;
}
RefPtr<nsObserverService> observerService;
CallGetService("@mozilla.org/observer-service;1",
(nsObserverService**)getter_AddRefs(observerService));
if (observerService) {
+ mozilla::KillClearOnShutdown(ShutdownPhase::WillShutdown);
observerService->NotifyObservers(nullptr,
NS_XPCOM_WILL_SHUTDOWN_OBSERVER_ID,
nullptr);
nsCOMPtr<nsIServiceManager> mgr;
rv = NS_GetServiceManager(getter_AddRefs(mgr));
if (NS_SUCCEEDED(rv)) {
+ mozilla::KillClearOnShutdown(ShutdownPhase::Shutdown);
observerService->NotifyObservers(mgr, NS_XPCOM_SHUTDOWN_OBSERVER_ID,
nullptr);
}
}
// This must happen after the shutdown of media and widgets, which
// are triggered by the NS_XPCOM_SHUTDOWN_OBSERVER_ID notification.
NS_ProcessPendingEvents(thread);
gfxPlatform::ShutdownLayersIPC();
mozilla::scache::StartupCache::DeleteSingleton();
if (observerService)
+ mozilla::KillClearOnShutdown(ShutdownPhase::ShutdownThreads);
observerService->NotifyObservers(nullptr,
NS_XPCOM_SHUTDOWN_THREADS_OBSERVER_ID,
nullptr);
gXPCOMThreadsShutDown = true;
NS_ProcessPendingEvents(thread);
// Shutdown the timer thread and all timers that might still be alive before
@@ -887,27 +890,28 @@ ShutdownXPCOM(nsIServiceManager* aServMg
// Late-write checks needs to find the profile directory, so it has to
// be initialized before mozilla::services::Shutdown or (because of
// xpcshell tests replacing the service) modules being unloaded.
mozilla::InitLateWriteChecks();
// We save the "xpcom-shutdown-loaders" observers to notify after
// the observerservice is gone.
if (observerService) {
+ mozilla::KillClearOnShutdown(ShutdownPhase::ShutdownLoaders);
observerService->EnumerateObservers(NS_XPCOM_SHUTDOWN_LOADERS_OBSERVER_ID,
getter_AddRefs(moduleLoaders));
observerService->Shutdown();
}
}
// Free ClearOnShutdown()'ed smart pointers. This needs to happen *after*
// we've finished notifying observers of XPCOM shutdown, because shutdown
// observers themselves might call ClearOnShutdown().
- mozilla::KillClearOnShutdown();
+ mozilla::KillClearOnShutdown(ShutdownPhase::ShutdownFinal);
// XPCOM is officially in shutdown mode NOW
// Set this only after the observers have been notified as this
// will cause servicemanager to become inaccessible.
mozilla::services::Shutdown();
#ifdef DEBUG_dougt
fprintf(stderr, "* * * * XPCOM shutdown. Access will be denied * * * * \n");