mirror of
https://github.com/mozilla/gecko-dev.git
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39004db706
* * * Bug 936964 (part 7b) - Fix a use-after-free found by ASan. --HG-- extra : rebase_source : d38ab6b63e9d576773baf8e55fa4f7182c33915e
333 lines
10 KiB
C++
333 lines
10 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "prlog.h"
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#include "nsAutoPtr.h"
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#include "nsIObserverService.h"
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#include "nsIObserver.h"
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#include "nsObserverService.h"
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#include "nsObserverList.h"
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#include "nsThreadUtils.h"
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#include "nsEnumeratorUtils.h"
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#include "mozilla/net/NeckoCommon.h"
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#include "mozilla/Services.h"
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#define NOTIFY_GLOBAL_OBSERVERS
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#if defined(PR_LOGGING)
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// Log module for nsObserverService logging...
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//
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// To enable logging (see prlog.h for full details):
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//
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// set NSPR_LOG_MODULES=ObserverService:5
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// set NSPR_LOG_FILE=nspr.log
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//
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// this enables PR_LOG_DEBUG level information and places all output in
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// the file nspr.log
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static PRLogModuleInfo*
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GetObserverServiceLog()
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{
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static PRLogModuleInfo *sLog;
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if (!sLog)
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sLog = PR_NewLogModule("ObserverService");
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return sLog;
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}
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#define LOG(x) PR_LOG(GetObserverServiceLog(), PR_LOG_DEBUG, x)
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#else
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#define LOG(x)
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#endif /* PR_LOGGING */
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namespace mozilla {
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struct SuspectObserver {
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SuspectObserver(const char* aTopic, size_t aReferentCount)
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: topic(aTopic), referentCount(aReferentCount) {}
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const char* topic;
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size_t referentCount;
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};
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struct ObserverServiceReferentCount {
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ObserverServiceReferentCount()
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: numStrong(0), numWeakAlive(0), numWeakDead(0) {}
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size_t numStrong;
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size_t numWeakAlive;
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size_t numWeakDead;
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nsTArray<SuspectObserver> suspectObservers;
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};
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} // namespace mozilla
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using namespace mozilla;
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PLDHashOperator
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nsObserverService::CountReferents(nsObserverList* aObserverList,
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void* aClosure)
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{
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if (!aObserverList) {
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return PL_DHASH_NEXT;
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}
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ObserverServiceReferentCount* referentCount =
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static_cast<ObserverServiceReferentCount*>(aClosure);
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size_t numStrong = 0;
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size_t numWeakAlive = 0;
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size_t numWeakDead = 0;
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nsTArray<ObserverRef>& observers = aObserverList->mObservers;
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for (uint32_t i = 0; i < observers.Length(); i++) {
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if (observers[i].isWeakRef) {
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nsCOMPtr<nsIObserver> observerRef(
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do_QueryReferent(observers[i].asWeak()));
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if (observerRef) {
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numWeakAlive++;
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} else {
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numWeakDead++;
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}
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} else {
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numStrong++;
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}
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}
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referentCount->numStrong += numStrong;
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referentCount->numWeakAlive += numWeakAlive;
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referentCount->numWeakDead += numWeakDead;
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// Keep track of topics that have a suspiciously large number
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// of referents (symptom of leaks).
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size_t total = numStrong + numWeakAlive + numWeakDead;
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if (total > kSuspectReferentCount) {
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SuspectObserver suspect(aObserverList->GetKey(), total);
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referentCount->suspectObservers.AppendElement(suspect);
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}
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return PL_DHASH_NEXT;
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}
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NS_IMETHODIMP
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nsObserverService::CollectReports(nsIHandleReportCallback* aHandleReport,
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nsISupports* aData)
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{
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ObserverServiceReferentCount referentCount;
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mObserverTopicTable.EnumerateEntries(CountReferents, &referentCount);
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nsresult rv;
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for (uint32_t i = 0; i < referentCount.suspectObservers.Length(); i++) {
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SuspectObserver& suspect = referentCount.suspectObservers[i];
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nsPrintfCString suspectPath("observer-service-suspect/"
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"referent(topic=%s)",
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suspect.topic);
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rv = aHandleReport->Callback(/* process */ EmptyCString(),
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suspectPath, KIND_OTHER, UNITS_COUNT, suspect.referentCount,
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NS_LITERAL_CSTRING("A topic with a suspiciously large number of "
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"referents. This may be symptomatic of a leak "
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"if the number of referents is high with "
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"respect to the number of windows."),
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aData);
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if (NS_WARN_IF(NS_FAILED(rv)))
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return rv;
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}
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rv = aHandleReport->Callback(/* process */ EmptyCString(),
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NS_LITERAL_CSTRING("observer-service/referent/strong"),
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KIND_OTHER, UNITS_COUNT, referentCount.numStrong,
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NS_LITERAL_CSTRING("The number of strong references held by the "
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"observer service."),
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aData);
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if (NS_WARN_IF(NS_FAILED(rv)))
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return rv;
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rv = aHandleReport->Callback(/* process */ EmptyCString(),
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NS_LITERAL_CSTRING("observer-service/referent/weak/alive"),
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KIND_OTHER, UNITS_COUNT, referentCount.numWeakAlive,
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NS_LITERAL_CSTRING("The number of weak references held by the "
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"observer service that are still alive."),
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aData);
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if (NS_WARN_IF(NS_FAILED(rv)))
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return rv;
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rv = aHandleReport->Callback(/* process */ EmptyCString(),
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NS_LITERAL_CSTRING("observer-service/referent/weak/dead"),
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KIND_OTHER, UNITS_COUNT, referentCount.numWeakDead,
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NS_LITERAL_CSTRING("The number of weak references held by the "
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"observer service that are dead."),
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aData);
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if (NS_WARN_IF(NS_FAILED(rv)))
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return rv;
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return NS_OK;
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}
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////////////////////////////////////////////////////////////////////////////////
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// nsObserverService Implementation
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NS_IMPL_ISUPPORTS_INHERITED2(
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nsObserverService,
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MemoryMultiReporter,
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nsIObserverService,
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nsObserverService)
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nsObserverService::nsObserverService() :
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MemoryMultiReporter("observer-service"),
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mShuttingDown(false)
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{
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}
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nsObserverService::~nsObserverService(void)
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{
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Shutdown();
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}
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void
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nsObserverService::RegisterReporter()
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{
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RegisterWeakMemoryReporter(this);
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}
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void
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nsObserverService::Shutdown()
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{
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UnregisterWeakMemoryReporter(this);
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mShuttingDown = true;
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mObserverTopicTable.Clear();
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}
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nsresult
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nsObserverService::Create(nsISupports* outer, const nsIID& aIID, void* *aInstancePtr)
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{
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LOG(("nsObserverService::Create()"));
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nsRefPtr<nsObserverService> os = new nsObserverService();
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if (!os)
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return NS_ERROR_OUT_OF_MEMORY;
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// The memory reporter can not be immediately registered here because
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// the nsMemoryReporterManager may attempt to get the nsObserverService
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// during initialization, causing a recursive GetService.
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nsRefPtr<nsRunnableMethod<nsObserverService> > registerRunnable =
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NS_NewRunnableMethod(os, &nsObserverService::RegisterReporter);
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NS_DispatchToCurrentThread(registerRunnable);
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return os->QueryInterface(aIID, aInstancePtr);
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}
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#define NS_ENSURE_VALIDCALL \
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if (!NS_IsMainThread()) { \
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NS_ERROR("Using observer service off the main thread!"); \
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return NS_ERROR_UNEXPECTED; \
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} \
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if (mShuttingDown) { \
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NS_ERROR("Using observer service after XPCOM shutdown!"); \
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return NS_ERROR_ILLEGAL_DURING_SHUTDOWN; \
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}
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NS_IMETHODIMP
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nsObserverService::AddObserver(nsIObserver* anObserver, const char* aTopic,
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bool ownsWeak)
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{
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LOG(("nsObserverService::AddObserver(%p: %s)",
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(void*) anObserver, aTopic));
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NS_ENSURE_VALIDCALL
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if (NS_WARN_IF(!anObserver) || NS_WARN_IF(!aTopic))
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return NS_ERROR_INVALID_ARG;
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if (mozilla::net::IsNeckoChild() && !strncmp(aTopic, "http-on-", 8)) {
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return NS_ERROR_NOT_IMPLEMENTED;
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}
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nsObserverList *observerList = mObserverTopicTable.PutEntry(aTopic);
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if (!observerList)
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return NS_ERROR_OUT_OF_MEMORY;
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return observerList->AddObserver(anObserver, ownsWeak);
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}
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NS_IMETHODIMP
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nsObserverService::RemoveObserver(nsIObserver* anObserver, const char* aTopic)
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{
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LOG(("nsObserverService::RemoveObserver(%p: %s)",
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(void*) anObserver, aTopic));
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NS_ENSURE_VALIDCALL
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if (NS_WARN_IF(!anObserver) || NS_WARN_IF(!aTopic))
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return NS_ERROR_INVALID_ARG;
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nsObserverList *observerList = mObserverTopicTable.GetEntry(aTopic);
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if (!observerList)
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return NS_ERROR_FAILURE;
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/* This death grip is to protect against stupid consumers who call
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RemoveObserver from their Destructor, see bug 485834/bug 325392. */
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nsCOMPtr<nsIObserver> kungFuDeathGrip(anObserver);
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return observerList->RemoveObserver(anObserver);
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}
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NS_IMETHODIMP
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nsObserverService::EnumerateObservers(const char* aTopic,
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nsISimpleEnumerator** anEnumerator)
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{
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NS_ENSURE_VALIDCALL
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if (NS_WARN_IF(!anEnumerator) || NS_WARN_IF(!aTopic))
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return NS_ERROR_INVALID_ARG;
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nsObserverList *observerList = mObserverTopicTable.GetEntry(aTopic);
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if (!observerList)
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return NS_NewEmptyEnumerator(anEnumerator);
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return observerList->GetObserverList(anEnumerator);
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}
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// Enumerate observers of aTopic and call Observe on each.
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NS_IMETHODIMP nsObserverService::NotifyObservers(nsISupports *aSubject,
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const char *aTopic,
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const PRUnichar *someData)
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{
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LOG(("nsObserverService::NotifyObservers(%s)", aTopic));
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NS_ENSURE_VALIDCALL
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if (NS_WARN_IF(!aTopic))
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return NS_ERROR_INVALID_ARG;
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nsObserverList *observerList = mObserverTopicTable.GetEntry(aTopic);
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if (observerList)
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observerList->NotifyObservers(aSubject, aTopic, someData);
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#ifdef NOTIFY_GLOBAL_OBSERVERS
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observerList = mObserverTopicTable.GetEntry("*");
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if (observerList)
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observerList->NotifyObservers(aSubject, aTopic, someData);
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#endif
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return NS_OK;
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}
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static PLDHashOperator
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UnmarkGrayObserverEntry(nsObserverList* aObserverList, void* aClosure)
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{
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if (aObserverList) {
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aObserverList->UnmarkGrayStrongObservers();
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}
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return PL_DHASH_NEXT;
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}
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NS_IMETHODIMP
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nsObserverService::UnmarkGrayStrongObservers()
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{
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NS_ENSURE_VALIDCALL
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mObserverTopicTable.EnumerateEntries(UnmarkGrayObserverEntry, nullptr);
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return NS_OK;
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}
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