/* -*- 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 "nsAutoPtr.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/Services.h"

#include "mozilla/Telemetry.h"

#include "mozilla/TimeStamp.h"

#include "nsString.h"

#include "GeckoProfiler.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;

    nsTArray<ObserverRef>& observers = observerList->mObservers;

    for (uint32_t i = 0; i < observers.Length(); i++) {

      if (observers[i].isWeakRef) {

        nsCOMPtr<nsIObserver> observerRef(

          do_QueryReferent(observers[i].asWeak()));

        if (observerRef) {

          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 */ EmptyCString(),

      suspectPath, KIND_OTHER, UNITS_COUNT, suspect.mReferentCount,

      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);

  }

  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()

{

  UnregisterWeakMemoryReporter(this);

  mShuttingDown = true;

  mObserverTopicTable.Clear();

}

nsresult

nsObserverService::Create(nsISupports* aOuter, const nsIID& aIID,

                          void** aInstancePtr)

{

  LOG(("nsObserverService::Create()"));

  RefPtr<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.

  NS_DispatchToCurrentThread(

    NewRunnableMethod("nsObserverService::RegisterReporter",

                      os,

                      &nsObserverService::RegisterReporter));

  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* aObserver, const char* aTopic,

                               bool aOwnsWeak)

{

  LOG(("nsObserverService::AddObserver(%p: %s)",

       (void*)aObserver, aTopic));

  NS_ENSURE_VALIDCALL

  if (NS_WARN_IF(!aObserver) || NS_WARN_IF(!aTopic)) {

    return NS_ERROR_INVALID_ARG;

  }

  // 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-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(NS_LITERAL_STRING("http-on-* observers only work in the parent process"),

                EmptyString(), EmptyString(), 0, 0,

                nsIScriptError::warningFlag, "chrome javascript",

                false /* from private window */);

    console->LogMessage(error);

    return NS_ERROR_NOT_IMPLEMENTED;

  }

  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));

  NS_ENSURE_VALIDCALL

  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;

  }

  /* This death grip is to protect against stupid consumers who call

     RemoveObserver from their Destructor, see bug 485834/bug 325392. */

  nsCOMPtr<nsIObserver> kungFuDeathGrip(aObserver);

  return observerList->RemoveObserver(aObserver);

}

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);

  }

  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));

  NS_ENSURE_VALIDCALL

  if (NS_WARN_IF(!aTopic)) {

    return NS_ERROR_INVALID_ARG;

  }

  mozilla::TimeStamp start = TimeStamp::Now();

  AUTO_PROFILER_LABEL_DYNAMIC_CSTR(

    "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()

{

  NS_ENSURE_VALIDCALL

  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;

}