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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/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"
static const uint32_t kMinTelemetryNotifyObserversLatencyMs = 1;
// 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(nsISupports* aOuter, 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")) {
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", 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;
}
mozilla::TimeStamp start = TimeStamp::Now();
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);
}
uint32_t latencyMs = round((TimeStamp::Now() - start).ToMilliseconds());
if (latencyMs >= kMinTelemetryNotifyObserversLatencyMs) {
Telemetry::Accumulate(Telemetry::NOTIFY_OBSERVERS_LATENCY_MS,
nsDependentCString(aTopic), latencyMs);
}
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;
}
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() {
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;
}