dom/broadcastchannel/BroadcastChannel.cpp

/* -*- 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 "BroadcastChannel.h"
#include "BroadcastChannelChild.h"
#include "mozilla/dom/BroadcastChannelBinding.h"
#include "mozilla/dom/Navigator.h"
#include "mozilla/dom/File.h"
#include "mozilla/dom/StructuredCloneHolder.h"
#include "mozilla/dom/ipc/StructuredCloneData.h"
#include "mozilla/dom/WorkerPrivate.h"
#include "mozilla/dom/WorkerRunnable.h"
#include "mozilla/ipc/BackgroundChild.h"
#include "mozilla/ipc/BackgroundUtils.h"
#include "mozilla/ipc/PBackgroundChild.h"
#include "nsContentUtils.h"

#include "nsIBFCacheEntry.h"
#include "nsIDocument.h"
#include "nsISupportsPrimitives.h"

#ifdef XP_WIN
#undef PostMessage
#endif

namespace mozilla {

using namespace ipc;

namespace dom {

using namespace ipc;

class BroadcastChannelMessage final : public StructuredCloneDataNoTransfers {
 public:
  NS_INLINE_DECL_REFCOUNTING(BroadcastChannelMessage)

  BroadcastChannelMessage() : StructuredCloneDataNoTransfers() {}

 private:
  ~BroadcastChannelMessage() {}
};

namespace {

nsIPrincipal* GetPrincipalFromWorkerPrivate(WorkerPrivate* aWorkerPrivate) {
  nsIPrincipal* principal = aWorkerPrivate->GetPrincipal();
  if (principal) {
    return principal;
  }

  // Walk up to our containing page
  WorkerPrivate* wp = aWorkerPrivate;
  while (wp->GetParent()) {
    wp = wp->GetParent();
  }

  return wp->GetPrincipal();
}

class InitializeRunnable final : public WorkerMainThreadRunnable {
 public:
  InitializeRunnable(WorkerPrivate* aWorkerPrivate, nsACString& aOrigin,
                     PrincipalInfo& aPrincipalInfo, ErrorResult& aRv)
      : WorkerMainThreadRunnable(
            aWorkerPrivate,
            NS_LITERAL_CSTRING("BroadcastChannel :: Initialize")),
        mWorkerPrivate(GetCurrentThreadWorkerPrivate()),
        mOrigin(aOrigin),
        mPrincipalInfo(aPrincipalInfo),
        mRv(aRv) {
    MOZ_ASSERT(mWorkerPrivate);
  }

  bool MainThreadRun() override {
    MOZ_ASSERT(NS_IsMainThread());

    nsIPrincipal* principal = GetPrincipalFromWorkerPrivate(mWorkerPrivate);
    if (!principal) {
      mRv.Throw(NS_ERROR_FAILURE);
      return true;
    }

    mRv = PrincipalToPrincipalInfo(principal, &mPrincipalInfo);
    if (NS_WARN_IF(mRv.Failed())) {
      return true;
    }

    mRv = principal->GetOrigin(mOrigin);
    if (NS_WARN_IF(mRv.Failed())) {
      return true;
    }

    // Walk up to our containing page
    WorkerPrivate* wp = mWorkerPrivate;
    while (wp->GetParent()) {
      wp = wp->GetParent();
    }

    // Window doesn't exist for some kind of workers (eg: SharedWorkers)
    nsPIDOMWindowInner* window = wp->GetWindow();
    if (!window) {
      return true;
    }

    return true;
  }

 private:
  WorkerPrivate* mWorkerPrivate;
  nsACString& mOrigin;
  PrincipalInfo& mPrincipalInfo;
  ErrorResult& mRv;
};

class BCPostMessageRunnable final : public nsIRunnable,
                                    public nsICancelableRunnable {
 public:
  NS_DECL_ISUPPORTS

  BCPostMessageRunnable(BroadcastChannelChild* aActor,
                        BroadcastChannelMessage* aData)
      : mActor(aActor), mData(aData) {
    MOZ_ASSERT(mActor);
  }

  NS_IMETHOD Run() override {
    MOZ_ASSERT(mActor);
    if (mActor->IsActorDestroyed()) {
      return NS_OK;
    }

    ClonedMessageData message;
    mData->BuildClonedMessageDataForBackgroundChild(mActor->Manager(), message);
    mActor->SendPostMessage(message);
    return NS_OK;
  }

  nsresult Cancel() override {
    mActor = nullptr;
    return NS_OK;
  }

 private:
  ~BCPostMessageRunnable() {}

  RefPtr<BroadcastChannelChild> mActor;
  RefPtr<BroadcastChannelMessage> mData;
};

NS_IMPL_ISUPPORTS(BCPostMessageRunnable, nsICancelableRunnable, nsIRunnable)

class CloseRunnable final : public nsIRunnable, public nsICancelableRunnable {
 public:
  NS_DECL_ISUPPORTS

  explicit CloseRunnable(BroadcastChannel* aBC) : mBC(aBC) { MOZ_ASSERT(mBC); }

  NS_IMETHOD Run() override {
    mBC->Shutdown();
    return NS_OK;
  }

  nsresult Cancel() override { return NS_OK; }

 private:
  ~CloseRunnable() {}

  RefPtr<BroadcastChannel> mBC;
};

NS_IMPL_ISUPPORTS(CloseRunnable, nsICancelableRunnable, nsIRunnable)

class TeardownRunnable {
 protected:
  explicit TeardownRunnable(BroadcastChannelChild* aActor) : mActor(aActor) {
    MOZ_ASSERT(mActor);
  }

  void RunInternal() {
    MOZ_ASSERT(mActor);
    if (!mActor->IsActorDestroyed()) {
      mActor->SendClose();
    }
  }

 protected:
  virtual ~TeardownRunnable() = default;

 private:
  RefPtr<BroadcastChannelChild> mActor;
};

class TeardownRunnableOnMainThread final : public Runnable,
                                           public TeardownRunnable {
 public:
  explicit TeardownRunnableOnMainThread(BroadcastChannelChild* aActor)
      : Runnable("TeardownRunnableOnMainThread"), TeardownRunnable(aActor) {}

  NS_IMETHOD Run() override {
    RunInternal();
    return NS_OK;
  }
};

class TeardownRunnableOnWorker final : public WorkerControlRunnable,
                                       public TeardownRunnable {
 public:
  TeardownRunnableOnWorker(WorkerPrivate* aWorkerPrivate,
                           BroadcastChannelChild* aActor)
      : WorkerControlRunnable(aWorkerPrivate, WorkerThreadUnchangedBusyCount),
        TeardownRunnable(aActor) {}

  bool WorkerRun(JSContext*, WorkerPrivate*) override {
    RunInternal();
    return true;
  }

  bool PreDispatch(WorkerPrivate* aWorkerPrivate) override { return true; }

  void PostDispatch(WorkerPrivate* aWorkerPrivate,
                    bool aDispatchResult) override {}

  bool PreRun(WorkerPrivate* aWorkerPrivate) override { return true; }

  void PostRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate,
               bool aRunResult) override {}
};

class BroadcastChannelWorkerHolder final : public WorkerHolder {
  BroadcastChannel* mChannel;

 public:
  explicit BroadcastChannelWorkerHolder(BroadcastChannel* aChannel)
      : WorkerHolder("BroadcastChannelWorkerHolder"), mChannel(aChannel) {
    MOZ_COUNT_CTOR(BroadcastChannelWorkerHolder);
  }

  virtual bool Notify(WorkerStatus aStatus) override {
    if (aStatus >= Closing) {
      mChannel->Shutdown();
    }

    return true;
  }

 private:
  ~BroadcastChannelWorkerHolder() {
    MOZ_COUNT_DTOR(BroadcastChannelWorkerHolder);
  }
};

}  // namespace

BroadcastChannel::BroadcastChannel(nsPIDOMWindowInner* aWindow,
                                   const PrincipalInfo& aPrincipalInfo,
                                   const nsACString& aOrigin,
                                   const nsAString& aChannel)
    : DOMEventTargetHelper(aWindow),
      mWorkerHolder(nullptr),
      mChannel(aChannel),
      mInnerID(0),
      mState(StateActive) {
  // Window can be null in workers

  KeepAliveIfHasListenersFor(NS_LITERAL_STRING("message"));
}

BroadcastChannel::~BroadcastChannel() {
  Shutdown();
  MOZ_ASSERT(!mWorkerHolder);
}

JSObject* BroadcastChannel::WrapObject(JSContext* aCx,
                                       JS::Handle<JSObject*> aGivenProto) {
  return BroadcastChannelBinding::Wrap(aCx, this, aGivenProto);
}

/* static */ already_AddRefed<BroadcastChannel> BroadcastChannel::Constructor(
    const GlobalObject& aGlobal, const nsAString& aChannel, ErrorResult& aRv) {
  nsCOMPtr<nsPIDOMWindowInner> window =
      do_QueryInterface(aGlobal.GetAsSupports());
  // Window is null in workers.

  nsAutoCString origin;
  PrincipalInfo principalInfo;
  WorkerPrivate* workerPrivate = nullptr;

  if (NS_IsMainThread()) {
    nsCOMPtr<nsIGlobalObject> incumbent = mozilla::dom::GetIncumbentGlobal();

    if (!incumbent) {
      aRv.Throw(NS_ERROR_FAILURE);
      return nullptr;
    }

    nsIPrincipal* principal = incumbent->PrincipalOrNull();
    if (!principal) {
      aRv.Throw(NS_ERROR_UNEXPECTED);
      return nullptr;
    }

    aRv = principal->GetOrigin(origin);
    if (NS_WARN_IF(aRv.Failed())) {
      return nullptr;
    }

    aRv = PrincipalToPrincipalInfo(principal, &principalInfo);
    if (NS_WARN_IF(aRv.Failed())) {
      return nullptr;
    }
  } else {
    JSContext* cx = aGlobal.Context();
    workerPrivate = GetWorkerPrivateFromContext(cx);
    MOZ_ASSERT(workerPrivate);

    RefPtr<InitializeRunnable> runnable =
        new InitializeRunnable(workerPrivate, origin, principalInfo, aRv);
    runnable->Dispatch(Closing, aRv);
  }

  if (aRv.Failed()) {
    return nullptr;
  }

  RefPtr<BroadcastChannel> bc =
      new BroadcastChannel(window, principalInfo, origin, aChannel);

  // Register this component to PBackground.
  PBackgroundChild* actorChild = BackgroundChild::GetOrCreateForCurrentThread();
  if (NS_WARN_IF(!actorChild)) {
    // Firefox is probably shutting down. Let's return a 'generic' error.
    aRv.Throw(NS_ERROR_FAILURE);
    return nullptr;
  }

  PBroadcastChannelChild* actor = actorChild->SendPBroadcastChannelConstructor(
      principalInfo, origin, nsString(aChannel));

  bc->mActor = static_cast<BroadcastChannelChild*>(actor);
  MOZ_ASSERT(bc->mActor);

  bc->mActor->SetParent(bc);

  if (!workerPrivate) {
    MOZ_ASSERT(window);
    bc->mInnerID = window->WindowID();

    // Register as observer for inner-window-destroyed.
    nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
    if (obs) {
      obs->AddObserver(bc, "inner-window-destroyed", false);
    }
  } else {
    bc->mWorkerHolder = new BroadcastChannelWorkerHolder(bc);
    if (NS_WARN_IF(!bc->mWorkerHolder->HoldWorker(workerPrivate, Closing))) {
      bc->mWorkerHolder = nullptr;
      aRv.Throw(NS_ERROR_FAILURE);
      return nullptr;
    }
  }

  return bc.forget();
}

void BroadcastChannel::PostMessage(JSContext* aCx,
                                   JS::Handle<JS::Value> aMessage,
                                   ErrorResult& aRv) {
  if (mState != StateActive) {
    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
    return;
  }

  PostMessageInternal(aCx, aMessage, aRv);
}

void BroadcastChannel::PostMessageInternal(JSContext* aCx,
                                           JS::Handle<JS::Value> aMessage,
                                           ErrorResult& aRv) {
  RefPtr<BroadcastChannelMessage> data = new BroadcastChannelMessage();

  data->Write(aCx, aMessage, aRv);
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  PostMessageData(data);
}

void BroadcastChannel::PostMessageData(BroadcastChannelMessage* aData) {
  RemoveDocFromBFCache();

  RefPtr<BCPostMessageRunnable> runnable =
      new BCPostMessageRunnable(mActor, aData);

  if (NS_FAILED(NS_DispatchToCurrentThread(runnable))) {
    NS_WARNING("Failed to dispatch to the current thread!");
  }
}

void BroadcastChannel::Close() {
  if (mState != StateActive) {
    return;
  }

  // We cannot call Shutdown() immediatelly because we could have some
  // postMessage runnable already dispatched. Instead, we change the state to
  // StateClosed and we shutdown the actor asynchrounsly.

  mState = StateClosed;
  RefPtr<CloseRunnable> runnable = new CloseRunnable(this);

  if (NS_FAILED(NS_DispatchToCurrentThread(runnable))) {
    NS_WARNING("Failed to dispatch to the current thread!");
  }
}

void BroadcastChannel::Shutdown() {
  mState = StateClosed;

  // The DTOR of this WorkerHolder will release the worker for us.
  mWorkerHolder = nullptr;

  if (mActor) {
    mActor->SetParent(nullptr);

    if (NS_IsMainThread()) {
      RefPtr<TeardownRunnableOnMainThread> runnable =
          new TeardownRunnableOnMainThread(mActor);
      NS_DispatchToCurrentThread(runnable);
    } else {
      WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();
      MOZ_ASSERT(workerPrivate);

      RefPtr<TeardownRunnableOnWorker> runnable =
          new TeardownRunnableOnWorker(workerPrivate, mActor);
      runnable->Dispatch();
    }

    mActor = nullptr;
  }

  IgnoreKeepAliveIfHasListenersFor(NS_LITERAL_STRING("message"));
}

NS_IMETHODIMP
BroadcastChannel::Observe(nsISupports* aSubject, const char* aTopic,
                          const char16_t* aData) {
  MOZ_ASSERT(NS_IsMainThread());
  MOZ_ASSERT(!strcmp(aTopic, "inner-window-destroyed"));

  // If the window is destroyed we have to release the reference that we are
  // keeping.
  nsCOMPtr<nsISupportsPRUint64> wrapper = do_QueryInterface(aSubject);
  NS_ENSURE_TRUE(wrapper, NS_ERROR_FAILURE);

  uint64_t innerID;
  nsresult rv = wrapper->GetData(&innerID);
  NS_ENSURE_SUCCESS(rv, rv);

  if (innerID == mInnerID) {
    nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
    if (obs) {
      obs->RemoveObserver(this, "inner-window-destroyed");
    }

    Shutdown();
  }

  return NS_OK;
}

void BroadcastChannel::RemoveDocFromBFCache() {
  if (!NS_IsMainThread()) {
    return;
  }

  nsPIDOMWindowInner* window = GetOwner();
  if (!window) {
    return;
  }

  nsIDocument* doc = window->GetExtantDoc();
  if (!doc) {
    return;
  }

  nsCOMPtr<nsIBFCacheEntry> bfCacheEntry = doc->GetBFCacheEntry();
  if (!bfCacheEntry) {
    return;
  }

  bfCacheEntry->RemoveFromBFCacheSync();
}

NS_IMPL_CYCLE_COLLECTION_CLASS(BroadcastChannel)

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(BroadcastChannel,
                                                  DOMEventTargetHelper)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(BroadcastChannel,
                                                DOMEventTargetHelper)
  tmp->Shutdown();
NS_IMPL_CYCLE_COLLECTION_UNLINK_END

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(BroadcastChannel)
  NS_INTERFACE_MAP_ENTRY(nsIObserver)
NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)

NS_IMPL_ADDREF_INHERITED(BroadcastChannel, DOMEventTargetHelper)
NS_IMPL_RELEASE_INHERITED(BroadcastChannel, DOMEventTargetHelper)

}  // namespace dom
}  // namespace mozilla