The Tor Browser: xpcom/ds/nsObserverService.cpp@b8a032363ba2 (annotated)

xpcom/ds/nsObserverService.cpp@b8a032363ba2 (annotated)

xpcom/ds/nsObserverService.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * 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/. */
 #include "prlog.h"
 #include "nsAutoPtr.h"
 #include "nsIObserverService.h"
 #include "nsIObserver.h"
 #include "nsObserverService.h"
 #include "nsObserverList.h"
 #include "nsThreadUtils.h"
 #include "nsEnumeratorUtils.h"
 #include "mozilla/net/NeckoCommon.h"
 #include "mozilla/Services.h"
 #define NOTIFY_GLOBAL_OBSERVERS
 #if defined(PR_LOGGING)
 // Log module for nsObserverService logging...
 //
 // To enable logging (see prlog.h for full details):
 //
 //    set NSPR_LOG_MODULES=ObserverService:5
 //    set NSPR_LOG_FILE=nspr.log
 //
 // this enables PR_LOG_DEBUG level information and places all output in
 // the file nspr.log
 static PRLogModuleInfo*
 GetObserverServiceLog()
 {
     static PRLogModuleInfo *sLog;
     if (!sLog)
         sLog = PR_NewLogModule("ObserverService");
     return sLog;
 }
   #define LOG(x)  PR_LOG(GetObserverServiceLog(), PR_LOG_DEBUG, x)
 #else
   #define LOG(x)
 #endif /* PR_LOGGING */
 namespace mozilla {
 struct SuspectObserver {
     SuspectObserver(const char* aTopic, size_t aReferentCount)
         : topic(aTopic), referentCount(aReferentCount) {}
     const char* topic;
     size_t referentCount;
 };
 struct ObserverServiceReferentCount {
     ObserverServiceReferentCount()
         : numStrong(0), numWeakAlive(0), numWeakDead(0) {}
     size_t numStrong;
     size_t numWeakAlive;
     size_t numWeakDead;
     nsTArray<SuspectObserver> suspectObservers;
 };
 } // namespace mozilla
 using namespace mozilla;
 PLDHashOperator
 nsObserverService::CountReferents(nsObserverList* aObserverList,
                                   void* aClosure)
 {
     if (!aObserverList) {
         return PL_DHASH_NEXT;
     }
     ObserverServiceReferentCount* referentCount =
         static_cast<ObserverServiceReferentCount*>(aClosure);
     size_t numStrong = 0;
     size_t numWeakAlive = 0;
     size_t numWeakDead = 0;
     nsTArray<ObserverRef>& observers = aObserverList->mObservers;
     for (uint32_t i = 0; i < observers.Length(); i++) {
         if (observers[i].isWeakRef) {
             nsCOMPtr<nsIObserver> observerRef(
                 do_QueryReferent(observers[i].asWeak()));
             if (observerRef) {
                 numWeakAlive++;
             } else {
                 numWeakDead++;
             }
         } else {
             numStrong++;
         }
     }
     referentCount->numStrong += numStrong;
     referentCount->numWeakAlive += numWeakAlive;
     referentCount->numWeakDead += numWeakDead;
     // Keep track of topics that have a suspiciously large number
     // of referents (symptom of leaks).
     size_t total = numStrong + numWeakAlive + numWeakDead;
     if (total > kSuspectReferentCount) {
         SuspectObserver suspect(aObserverList->GetKey(), total);
         referentCount->suspectObservers.AppendElement(suspect);
     }
     return PL_DHASH_NEXT;
 }
 NS_IMETHODIMP
 nsObserverService::CollectReports(nsIHandleReportCallback* aHandleReport,
                                   nsISupports* aData)
 {
     ObserverServiceReferentCount referentCount;
     mObserverTopicTable.EnumerateEntries(CountReferents, &referentCount);
     nsresult rv;
     for (uint32_t i = 0; i < referentCount.suspectObservers.Length(); i++) {
         SuspectObserver& suspect = referentCount.suspectObservers[i];
         nsPrintfCString suspectPath("observer-service-suspect/"
                                     "referent(topic=%s)",
                                     suspect.topic);
         rv = aHandleReport->Callback(/* process */ EmptyCString(),
             suspectPath, KIND_OTHER, UNITS_COUNT, suspect.referentCount,
             NS_LITERAL_CSTRING("A topic with a suspiciously large number of "
                                "referents.  This may be symptomatic of a leak "
                                "if the number of referents is high with "
                                "respect to the number of windows."),
             aData);
       if (NS_WARN_IF(NS_FAILED(rv)))
           return rv;
     }
     rv = aHandleReport->Callback(/* process */ EmptyCString(),
         NS_LITERAL_CSTRING("observer-service/referent/strong"),
         KIND_OTHER, UNITS_COUNT, referentCount.numStrong,
         NS_LITERAL_CSTRING("The number of strong references held by the "
                            "observer service."),
         aData);
     if (NS_WARN_IF(NS_FAILED(rv)))
         return rv;
     rv = aHandleReport->Callback(/* process */ EmptyCString(),
         NS_LITERAL_CSTRING("observer-service/referent/weak/alive"),
         KIND_OTHER, UNITS_COUNT, referentCount.numWeakAlive,
         NS_LITERAL_CSTRING("The number of weak references held by the "
                            "observer service that are still alive."),
         aData);
     if (NS_WARN_IF(NS_FAILED(rv)))
         return rv;
     rv = aHandleReport->Callback(/* process */ EmptyCString(),
         NS_LITERAL_CSTRING("observer-service/referent/weak/dead"),
         KIND_OTHER, UNITS_COUNT, referentCount.numWeakDead,
         NS_LITERAL_CSTRING("The number of weak references held by the "
                            "observer service that are dead."),
         aData);
     if (NS_WARN_IF(NS_FAILED(rv)))
         return rv;
     return NS_OK;
 }
 ////////////////////////////////////////////////////////////////////////////////
 // nsObserverService Implementation
 NS_IMPL_ISUPPORTS(
     nsObserverService,
     nsIObserverService,
     nsObserverService,
     nsIMemoryReporter)
 nsObserverService::nsObserverService() :
     mShuttingDown(false)
 {
 }
 nsObserverService::~nsObserverService(void)
 {
     Shutdown();
 }
 void
 nsObserverService::RegisterReporter()
 {
     RegisterWeakMemoryReporter(this);
 }
 void
 nsObserverService::Shutdown()
 {
     UnregisterWeakMemoryReporter(this);
     mShuttingDown = true;
     mObserverTopicTable.Clear();
 }
 nsresult
 nsObserverService::Create(nsISupports* outer, const nsIID& aIID, void* *aInstancePtr)
 {
     LOG(("nsObserverService::Create()"));
     nsRefPtr<nsObserverService> os = new nsObserverService();
     if (!os)
         return NS_ERROR_OUT_OF_MEMORY;
     // The memory reporter can not be immediately registered here because
     // the nsMemoryReporterManager may attempt to get the nsObserverService
     // during initialization, causing a recursive GetService.
     nsRefPtr<nsRunnableMethod<nsObserverService> > registerRunnable =
         NS_NewRunnableMethod(os, &nsObserverService::RegisterReporter);
     NS_DispatchToCurrentThread(registerRunnable);
     return os->QueryInterface(aIID, aInstancePtr);
 }
 #define NS_ENSURE_VALIDCALL \
     if (!NS_IsMainThread()) {                                     \
         MOZ_CRASH("Using observer service off the main thread!"); \
         return NS_ERROR_UNEXPECTED;                               \
     }                                                             \
     if (mShuttingDown) {                                          \
         NS_ERROR("Using observer service after XPCOM shutdown!"); \
         return NS_ERROR_ILLEGAL_DURING_SHUTDOWN;                  \
     }
 NS_IMETHODIMP
 nsObserverService::AddObserver(nsIObserver* anObserver, const char* aTopic,
                                bool ownsWeak)
 {
     LOG(("nsObserverService::AddObserver(%p: %s)",
          (void*) anObserver, aTopic));
     NS_ENSURE_VALIDCALL
     if (NS_WARN_IF(!anObserver) || NS_WARN_IF(!aTopic))
         return NS_ERROR_INVALID_ARG;
     if (mozilla::net::IsNeckoChild() && !strncmp(aTopic, "http-on-", 8)) {
       return NS_ERROR_NOT_IMPLEMENTED;
     }
     nsObserverList *observerList = mObserverTopicTable.PutEntry(aTopic);
     if (!observerList)
         return NS_ERROR_OUT_OF_MEMORY;
     return observerList->AddObserver(anObserver, ownsWeak);
 }
 NS_IMETHODIMP
 nsObserverService::RemoveObserver(nsIObserver* anObserver, const char* aTopic)
 {
     LOG(("nsObserverService::RemoveObserver(%p: %s)",
          (void*) anObserver, aTopic));
     NS_ENSURE_VALIDCALL
     if (NS_WARN_IF(!anObserver) || NS_WARN_IF(!aTopic))
         return NS_ERROR_INVALID_ARG;
     nsObserverList *observerList = mObserverTopicTable.GetEntry(aTopic);
     if (!observerList)
         return NS_ERROR_FAILURE;
     /* This death grip is to protect against stupid consumers who call
        RemoveObserver from their Destructor, see bug 485834/bug 325392. */
     nsCOMPtr<nsIObserver> kungFuDeathGrip(anObserver);
     return observerList->RemoveObserver(anObserver);
 }
 NS_IMETHODIMP
 nsObserverService::EnumerateObservers(const char* aTopic,
                                       nsISimpleEnumerator** anEnumerator)
 {
     NS_ENSURE_VALIDCALL
     if (NS_WARN_IF(!anEnumerator) || NS_WARN_IF(!aTopic))
         return NS_ERROR_INVALID_ARG;
     nsObserverList *observerList = mObserverTopicTable.GetEntry(aTopic);
     if (!observerList)
         return NS_NewEmptyEnumerator(anEnumerator);
     return observerList->GetObserverList(anEnumerator);
 }
 // Enumerate observers of aTopic and call Observe on each.
 NS_IMETHODIMP nsObserverService::NotifyObservers(nsISupports *aSubject,
                                                  const char *aTopic,
                                                  const char16_t *someData)
 {
     LOG(("nsObserverService::NotifyObservers(%s)", aTopic));
     NS_ENSURE_VALIDCALL
     if (NS_WARN_IF(!aTopic))
         return NS_ERROR_INVALID_ARG;
     nsObserverList *observerList = mObserverTopicTable.GetEntry(aTopic);
     if (observerList)
         observerList->NotifyObservers(aSubject, aTopic, someData);
 #ifdef NOTIFY_GLOBAL_OBSERVERS
     observerList = mObserverTopicTable.GetEntry("*");
     if (observerList)
         observerList->NotifyObservers(aSubject, aTopic, someData);
 #endif
     return NS_OK;
 }
 static PLDHashOperator
 UnmarkGrayObserverEntry(nsObserverList* aObserverList, void* aClosure)
 {
     if (aObserverList) {
         aObserverList->UnmarkGrayStrongObservers();
     }
     return PL_DHASH_NEXT;
 }
 NS_IMETHODIMP
 nsObserverService::UnmarkGrayStrongObservers()
 {
     NS_ENSURE_VALIDCALL
     mObserverTopicTable.EnumerateEntries(UnmarkGrayObserverEntry, nullptr);
     return NS_OK;
 }

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xpcom/ds/nsObserverService.cpp@b8a032363ba2 (annotated)

xpcom/ds/nsObserverService.cpp