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-rw-r--r--xpcom/ds/nsObserverService.cpp357
1 files changed, 357 insertions, 0 deletions
diff --git a/xpcom/ds/nsObserverService.cpp b/xpcom/ds/nsObserverService.cpp
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+++ b/xpcom/ds/nsObserverService.cpp
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+/* -*- 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;
+}