diff options
Diffstat (limited to 'xpcom/ds/nsObserverService.cpp')
| -rw-r--r-- | xpcom/ds/nsObserverService.cpp | 357 |
1 files changed, 357 insertions, 0 deletions
diff --git a/xpcom/ds/nsObserverService.cpp b/xpcom/ds/nsObserverService.cpp new file mode 100644 index 0000000000..5ed81b01a7 --- /dev/null +++ b/xpcom/ds/nsObserverService.cpp @@ -0,0 +1,357 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* 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 "mozilla/Logging.h" +#include "nsComponentManagerUtils.h" +#include "nsContentUtils.h" +#include "nsIConsoleService.h" +#include "nsIObserverService.h" +#include "nsIObserver.h" +#include "nsIScriptError.h" +#include "nsObserverService.h" +#include "nsObserverList.h" +#include "nsServiceManagerUtils.h" +#include "nsThreadUtils.h" +#include "nsEnumeratorUtils.h" +#include "xpcpublic.h" +#include "mozilla/AppShutdown.h" +#include "mozilla/net/NeckoCommon.h" +#include "mozilla/ProfilerLabels.h" +#include "mozilla/ProfilerMarkers.h" +#include "mozilla/ResultExtensions.h" +#include "mozilla/Telemetry.h" +#include "mozilla/TimeStamp.h" +#include "nsString.h" + +// Log module for nsObserverService logging... +// +// To enable logging (see prlog.h for full details): +// +// set MOZ_LOG=ObserverService:5 +// set MOZ_LOG_FILE=service.log +// +// This enables LogLevel::Debug level information and places all output in +// the file service.log. +static mozilla::LazyLogModule sObserverServiceLog("ObserverService"); +#define LOG(x) MOZ_LOG(sObserverServiceLog, mozilla::LogLevel::Debug, x) + +using namespace mozilla; + +NS_IMETHODIMP +nsObserverService::CollectReports(nsIHandleReportCallback* aHandleReport, + nsISupports* aData, bool aAnonymize) { + struct SuspectObserver { + SuspectObserver(const char* aTopic, size_t aReferentCount) + : mTopic(aTopic), mReferentCount(aReferentCount) {} + const char* mTopic; + size_t mReferentCount; + }; + + size_t totalNumStrong = 0; + size_t totalNumWeakAlive = 0; + size_t totalNumWeakDead = 0; + nsTArray<SuspectObserver> suspectObservers; + + for (auto iter = mObserverTopicTable.Iter(); !iter.Done(); iter.Next()) { + nsObserverList* observerList = iter.Get(); + if (!observerList) { + continue; + } + + size_t topicNumStrong = 0; + size_t topicNumWeakAlive = 0; + size_t topicNumWeakDead = 0; + + nsMaybeWeakPtrArray<nsIObserver>& observers = observerList->mObservers; + for (uint32_t i = 0; i < observers.Length(); i++) { + if (observers[i].IsWeak()) { + nsCOMPtr<nsIObserver> ref = observers[i].GetValue(); + if (ref) { + topicNumWeakAlive++; + } else { + topicNumWeakDead++; + } + } else { + topicNumStrong++; + } + } + + totalNumStrong += topicNumStrong; + totalNumWeakAlive += topicNumWeakAlive; + totalNumWeakDead += topicNumWeakDead; + + // Keep track of topics that have a suspiciously large number + // of referents (symptom of leaks). + size_t topicTotal = topicNumStrong + topicNumWeakAlive + topicNumWeakDead; + if (topicTotal > kSuspectReferentCount) { + SuspectObserver suspect(observerList->GetKey(), topicTotal); + suspectObservers.AppendElement(suspect); + } + } + + // These aren't privacy-sensitive and so don't need anonymizing. + for (uint32_t i = 0; i < suspectObservers.Length(); i++) { + SuspectObserver& suspect = suspectObservers[i]; + nsPrintfCString suspectPath("observer-service-suspect/referent(topic=%s)", + suspect.mTopic); + aHandleReport->Callback( + /* process */ ""_ns, suspectPath, KIND_OTHER, UNITS_COUNT, + suspect.mReferentCount, + nsLiteralCString("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); + } + + MOZ_COLLECT_REPORT( + "observer-service/referent/strong", KIND_OTHER, UNITS_COUNT, + totalNumStrong, + "The number of strong references held by the observer service."); + + MOZ_COLLECT_REPORT( + "observer-service/referent/weak/alive", KIND_OTHER, UNITS_COUNT, + totalNumWeakAlive, + "The number of weak references held by the observer service that are " + "still alive."); + + MOZ_COLLECT_REPORT( + "observer-service/referent/weak/dead", KIND_OTHER, UNITS_COUNT, + totalNumWeakDead, + "The number of weak references held by the observer service that are " + "dead."); + + 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() { + if (mShuttingDown) { + return; + } + + mShuttingDown = true; + UnregisterWeakMemoryReporter(this); + mObserverTopicTable.Clear(); +} + +nsresult nsObserverService::Create(const nsIID& aIID, void** aInstancePtr) { + LOG(("nsObserverService::Create()")); + + RefPtr<nsObserverService> os = new nsObserverService(); + + // The memory reporter can not be immediately registered here because + // the nsMemoryReporterManager may attempt to get the nsObserverService + // during initialization, causing a recursive GetService. + NS_DispatchToCurrentThread( + NewRunnableMethod("nsObserverService::RegisterReporter", os, + &nsObserverService::RegisterReporter)); + + return os->QueryInterface(aIID, aInstancePtr); +} + +nsresult nsObserverService::EnsureValidCall() const { + 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; + } + + return NS_OK; +} + +nsresult nsObserverService::FilterHttpOnTopics(const char* aTopic) { + // Specifically allow http-on-opening-request and http-on-stop-request in the + // child process; see bug 1269765. + if (mozilla::net::IsNeckoChild() && !strncmp(aTopic, "http-on-", 8) && + strcmp(aTopic, "http-on-failed-opening-request") && + strcmp(aTopic, "http-on-opening-request") && + strcmp(aTopic, "http-on-stop-request") && + strcmp(aTopic, "http-on-image-cache-response")) { + nsCOMPtr<nsIConsoleService> console( + do_GetService(NS_CONSOLESERVICE_CONTRACTID)); + nsCOMPtr<nsIScriptError> error( + do_CreateInstance(NS_SCRIPTERROR_CONTRACTID)); + error->Init(u"http-on-* observers only work in the parent process"_ns, + u""_ns, u""_ns, 0, 0, nsIScriptError::warningFlag, + "chrome javascript"_ns, false /* from private window */, + true /* from chrome context */); + console->LogMessage(error); + + return NS_ERROR_NOT_IMPLEMENTED; + } + + return NS_OK; +} + +NS_IMETHODIMP +nsObserverService::AddObserver(nsIObserver* aObserver, const char* aTopic, + bool aOwnsWeak) { + LOG(("nsObserverService::AddObserver(%p: %s, %s)", (void*)aObserver, aTopic, + aOwnsWeak ? "weak" : "strong")); + + MOZ_TRY(EnsureValidCall()); + if (NS_WARN_IF(!aObserver) || NS_WARN_IF(!aTopic)) { + return NS_ERROR_INVALID_ARG; + } + + MOZ_TRY(FilterHttpOnTopics(aTopic)); + + nsObserverList* observerList = mObserverTopicTable.PutEntry(aTopic); + if (!observerList) { + return NS_ERROR_OUT_OF_MEMORY; + } + + return observerList->AddObserver(aObserver, aOwnsWeak); +} + +NS_IMETHODIMP +nsObserverService::RemoveObserver(nsIObserver* aObserver, const char* aTopic) { + LOG(("nsObserverService::RemoveObserver(%p: %s)", (void*)aObserver, aTopic)); + + if (mShuttingDown) { + // The service is shutting down. Let's ignore this call. + return NS_OK; + } + + MOZ_TRY(EnsureValidCall()); + if (NS_WARN_IF(!aObserver) || NS_WARN_IF(!aTopic)) { + return NS_ERROR_INVALID_ARG; + } + + nsObserverList* observerList = mObserverTopicTable.GetEntry(aTopic); + if (!observerList) { + return NS_ERROR_FAILURE; + } + + return observerList->RemoveObserver(aObserver); +} + +NS_IMETHODIMP +nsObserverService::EnumerateObservers(const char* aTopic, + nsISimpleEnumerator** anEnumerator) { + LOG(("nsObserverService::EnumerateObservers(%s)", aTopic)); + + MOZ_TRY(EnsureValidCall()); + 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); + } + + observerList->GetObserverList(anEnumerator); + return NS_OK; +} + +// Enumerate observers of aTopic and call Observe on each. +NS_IMETHODIMP nsObserverService::NotifyObservers(nsISupports* aSubject, + const char* aTopic, + const char16_t* aSomeData) { + LOG(("nsObserverService::NotifyObservers(%s)", aTopic)); + + MOZ_TRY(EnsureValidCall()); + if (NS_WARN_IF(!aTopic)) { + return NS_ERROR_INVALID_ARG; + } + + MOZ_ASSERT(AppShutdown::IsNoOrLegalShutdownTopic(aTopic)); + + AUTO_PROFILER_MARKER_TEXT("NotifyObservers", OTHER, MarkerStack::Capture(), + nsDependentCString(aTopic)); + AUTO_PROFILER_LABEL_DYNAMIC_CSTR_NONSENSITIVE( + "nsObserverService::NotifyObservers", OTHER, aTopic); + + nsObserverList* observerList = mObserverTopicTable.GetEntry(aTopic); + if (observerList) { + observerList->NotifyObservers(aSubject, aTopic, aSomeData); + } + + return NS_OK; +} + +NS_IMETHODIMP +nsObserverService::UnmarkGrayStrongObservers() { + MOZ_TRY(EnsureValidCall()); + + nsCOMArray<nsIObserver> strongObservers; + for (auto iter = mObserverTopicTable.Iter(); !iter.Done(); iter.Next()) { + nsObserverList* aObserverList = iter.Get(); + if (aObserverList) { + aObserverList->AppendStrongObservers(strongObservers); + } + } + + for (uint32_t i = 0; i < strongObservers.Length(); ++i) { + xpc_TryUnmarkWrappedGrayObject(strongObservers[i]); + } + + return NS_OK; +} + +bool nsObserverService::HasObservers(const char* aTopic) { + return mObserverTopicTable.Contains(aTopic); +} + +namespace { + +class NotifyWhenScriptSafeRunnable : public mozilla::Runnable { + public: + NotifyWhenScriptSafeRunnable(nsIObserverService* aObs, nsISupports* aSubject, + const char* aTopic, const char16_t* aData) + : mozilla::Runnable("NotifyWhenScriptSafeRunnable"), + mObs(aObs), + mSubject(aSubject), + mTopic(aTopic) { + if (aData) { + mData.Assign(aData); + } else { + mData.SetIsVoid(true); + } + } + + NS_IMETHOD Run() override { + const char16_t* data = mData.IsVoid() ? nullptr : mData.get(); + return mObs->NotifyObservers(mSubject, mTopic.get(), data); + } + + private: + nsCOMPtr<nsIObserverService> mObs; + nsCOMPtr<nsISupports> mSubject; + nsCString mTopic; + nsString mData; +}; + +} // namespace + +nsresult nsIObserverService::NotifyWhenScriptSafe(nsISupports* aSubject, + const char* aTopic, + const char16_t* aData) { + if (nsContentUtils::IsSafeToRunScript()) { + return NotifyObservers(aSubject, aTopic, aData); + } + + nsContentUtils::AddScriptRunner(MakeAndAddRef<NotifyWhenScriptSafeRunnable>( + this, aSubject, aTopic, aData)); + return NS_OK; +} |