/* -*- 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 "IPCBlobInputStreamChild.h"

#include "IPCBlobInputStreamThread.h"

#include "mozilla/ipc/IPCStreamUtils.h"

#include "mozilla/dom/WorkerCommon.h"

#include "mozilla/dom/WorkerRef.h"

namespace mozilla {

namespace dom {

namespace {

// This runnable is used in case the last stream is forgotten on the 'wrong'

// thread.

class ShutdownRunnable final : public CancelableRunnable

{

public:

  explicit ShutdownRunnable(IPCBlobInputStreamChild* aActor)

    : CancelableRunnable("dom::ShutdownRunnable")

    , mActor(aActor)

  {}

  NS_IMETHOD

  Run() override

  {

    mActor->Shutdown();

    return NS_OK;

  }

private:

  RefPtr<IPCBlobInputStreamChild> mActor;

};

// This runnable is used in case StreamNeeded() has been called on a non-owning

// thread.

class StreamNeededRunnable final : public CancelableRunnable

{

public:

  explicit StreamNeededRunnable(IPCBlobInputStreamChild* aActor)

    : CancelableRunnable("dom::StreamNeededRunnable")

    , mActor(aActor)

  {}

  NS_IMETHOD

  Run() override

  {

    MOZ_ASSERT(mActor->State() != IPCBlobInputStreamChild::eActiveMigrating &&

               mActor->State() != IPCBlobInputStreamChild::eInactiveMigrating);

    if (mActor->State() == IPCBlobInputStreamChild::eActive) {

      mActor->SendStreamNeeded();

    }

    return NS_OK;

  }

private:

  RefPtr<IPCBlobInputStreamChild> mActor;

};

// When the stream has been received from the parent, we inform the

// IPCBlobInputStream.

class StreamReadyRunnable final : public CancelableRunnable

{

public:

  StreamReadyRunnable(IPCBlobInputStream* aDestinationStream,

                      already_AddRefed<nsIInputStream> aCreatedStream)

    : CancelableRunnable("dom::StreamReadyRunnable")

    , mDestinationStream(aDestinationStream)

    , mCreatedStream(std::move(aCreatedStream))

  {

    MOZ_ASSERT(mDestinationStream);

    // mCreatedStream can be null.

  }

  NS_IMETHOD

  Run() override

  {

    mDestinationStream->StreamReady(mCreatedStream.forget());

    return NS_OK;

  }

private:

  RefPtr<IPCBlobInputStream> mDestinationStream;

  nsCOMPtr<nsIInputStream> mCreatedStream;

};

// This runnable is used in case LengthNeeded() has been called on a non-owning

// thread.

class LengthNeededRunnable final : public CancelableRunnable

{

public:

  explicit LengthNeededRunnable(IPCBlobInputStreamChild* aActor)

    : CancelableRunnable("dom::LengthNeededRunnable")

    , mActor(aActor)

  {}

  NS_IMETHOD

  Run() override

  {

    MOZ_ASSERT(mActor->State() != IPCBlobInputStreamChild::eActiveMigrating &&

               mActor->State() != IPCBlobInputStreamChild::eInactiveMigrating);

    if (mActor->State() == IPCBlobInputStreamChild::eActive) {

      mActor->SendLengthNeeded();

    }

    return NS_OK;

  }

private:

  RefPtr<IPCBlobInputStreamChild> mActor;

};

// When the stream has been received from the parent, we inform the

// IPCBlobInputStream.

class LengthReadyRunnable final : public CancelableRunnable

{

public:

  LengthReadyRunnable(IPCBlobInputStream* aDestinationStream, int64_t aSize)

    : CancelableRunnable("dom::LengthReadyRunnable")

    , mDestinationStream(aDestinationStream)

    , mSize(aSize)

  {

    MOZ_ASSERT(mDestinationStream);

  }

  NS_IMETHOD

  Run() override

  {

    mDestinationStream->LengthReady(mSize);

    return NS_OK;

  }

private:

  RefPtr<IPCBlobInputStream> mDestinationStream;

  int64_t mSize;

};

} // anonymous

IPCBlobInputStreamChild::IPCBlobInputStreamChild(const nsID& aID,

                                                 uint64_t aSize)

  : mMutex("IPCBlobInputStreamChild::mMutex")

  , mID(aID)

  , mSize(aSize)

  , mState(eActive)

  , mOwningEventTarget(GetCurrentThreadSerialEventTarget())

{

  // If we are running in a worker, we need to send a Close() to the parent side

  // before the thread is released.

  if (!NS_IsMainThread()) {

    WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate();

    if (!workerPrivate) {

      return;

    }

    RefPtr<StrongWorkerRef> workerRef =

      StrongWorkerRef::Create(workerPrivate, "IPCBlobInputStreamChild");

    if (!workerRef) {

      return;

    }

    // We must keep the worker alive until the migration is completed.

    mWorkerRef = new ThreadSafeWorkerRef(workerRef);

  }

}

IPCBlobInputStreamChild::~IPCBlobInputStreamChild()

{}

void

IPCBlobInputStreamChild::Shutdown()

{

  MutexAutoLock lock(mMutex);

  RefPtr<IPCBlobInputStreamChild> kungFuDeathGrip = this;

  mWorkerRef = nullptr;

  mPendingOperations.Clear();

  if (mState == eActive) {

    SendClose();

    mState = eInactive;

  }

}

void

IPCBlobInputStreamChild::ActorDestroy(IProtocol::ActorDestroyReason aReason)

{

  bool migrating = false;

  {

    MutexAutoLock lock(mMutex);

    migrating = mState == eActiveMigrating;

    mState = migrating ? eInactiveMigrating : eInactive;

  }

  if (migrating) {

    // We were waiting for this! Now we can migrate the actor in the correct

    // thread.

    RefPtr<IPCBlobInputStreamThread> thread =

      IPCBlobInputStreamThread::GetOrCreate();

    MOZ_ASSERT(thread, "We cannot continue without DOMFile thread.");

    ResetManager();

    thread->MigrateActor(this);

    return;

  }

  // Let's cleanup the workerRef and the pending operation queue.

  Shutdown();

}

IPCBlobInputStreamChild::ActorState

IPCBlobInputStreamChild::State()

{

  MutexAutoLock lock(mMutex);

  return mState;

}

already_AddRefed<IPCBlobInputStream>

IPCBlobInputStreamChild::CreateStream()

{

  bool shouldMigrate = false;

  RefPtr<IPCBlobInputStream> stream = new IPCBlobInputStream(this);

  {

    MutexAutoLock lock(mMutex);

    if (mState == eInactive) {

      return nullptr;

    }

    // The stream is active but maybe it is not running in the DOM-File thread.

    // We should migrate it there.

    if (mState == eActive &&

        !IPCBlobInputStreamThread::IsOnFileEventTarget(mOwningEventTarget)) {

      MOZ_ASSERT(mStreams.IsEmpty());

      shouldMigrate = true;

      mState = eActiveMigrating;

    }

    mStreams.AppendElement(stream);

  }

  // Send__delete__ will call ActorDestroy(). mMutex cannot be locked at this

  // time.

  if (shouldMigrate) {

    Send__delete__(this);

  }

  return stream.forget();

}

void

IPCBlobInputStreamChild::ForgetStream(IPCBlobInputStream* aStream)

{

  MOZ_ASSERT(aStream);

  RefPtr<IPCBlobInputStreamChild> kungFuDeathGrip = this;

  {

    MutexAutoLock lock(mMutex);

    mStreams.RemoveElement(aStream);

    if (!mStreams.IsEmpty() || mState != eActive) {

      return;

    }

  }

  if (mOwningEventTarget->IsOnCurrentThread()) {

    Shutdown();

    return;

  }

  RefPtr<ShutdownRunnable> runnable = new ShutdownRunnable(this);

  mOwningEventTarget->Dispatch(runnable, NS_DISPATCH_NORMAL);

}

void

IPCBlobInputStreamChild::StreamNeeded(IPCBlobInputStream* aStream,

                                      nsIEventTarget* aEventTarget)

{

  MutexAutoLock lock(mMutex);

  if (mState == eInactive) {

    return;

  }

  MOZ_ASSERT(mStreams.Contains(aStream));

  PendingOperation* opt = mPendingOperations.AppendElement();

  opt->mStream = aStream;

  opt->mEventTarget = aEventTarget;

  opt->mOp = PendingOperation::eStreamNeeded;

  if (mState == eActiveMigrating || mState == eInactiveMigrating) {

    // This operation will be continued when the migration is completed.

    return;

  }

  MOZ_ASSERT(mState == eActive);

  if (mOwningEventTarget->IsOnCurrentThread()) {

    SendStreamNeeded();

    return;

  }

  RefPtr<StreamNeededRunnable> runnable = new StreamNeededRunnable(this);

  mOwningEventTarget->Dispatch(runnable.forget(), NS_DISPATCH_NORMAL);

}

mozilla::ipc::IPCResult

IPCBlobInputStreamChild::RecvStreamReady(const OptionalIPCStream& aStream)

{

  nsCOMPtr<nsIInputStream> stream = mozilla::ipc::DeserializeIPCStream(aStream);

  RefPtr<IPCBlobInputStream> pendingStream;

  nsCOMPtr<nsIEventTarget> eventTarget;

  {

    MutexAutoLock lock(mMutex);

    // We have been shutdown in the meantime.

    if (mState == eInactive) {

      return IPC_OK();

    }

    MOZ_ASSERT(!mPendingOperations.IsEmpty());

    MOZ_ASSERT(mState == eActive);

    pendingStream = mPendingOperations[0].mStream;

    eventTarget = mPendingOperations[0].mEventTarget;

    MOZ_ASSERT(mPendingOperations[0].mOp == PendingOperation::eStreamNeeded);

    mPendingOperations.RemoveElementAt(0);

  }

  RefPtr<StreamReadyRunnable> runnable =

    new StreamReadyRunnable(pendingStream, stream.forget());

  // If IPCBlobInputStream::AsyncWait() has been executed without passing an

  // event target, we run the callback synchronous because any thread could be

  // result to be the wrong one. See more in nsIAsyncInputStream::asyncWait

  // documentation.

  if (eventTarget) {

    eventTarget->Dispatch(runnable, NS_DISPATCH_NORMAL);

  } else {

    runnable->Run();

  }

  return IPC_OK();

}

void

IPCBlobInputStreamChild::LengthNeeded(IPCBlobInputStream* aStream,

                                      nsIEventTarget* aEventTarget)

{

  MutexAutoLock lock(mMutex);

  if (mState == eInactive) {

    return;

  }

  MOZ_ASSERT(mStreams.Contains(aStream));

  PendingOperation* opt = mPendingOperations.AppendElement();

  opt->mStream = aStream;

  opt->mEventTarget = aEventTarget;

  opt->mOp = PendingOperation::eLengthNeeded;

  if (mState == eActiveMigrating || mState == eInactiveMigrating) {

    // This operation will be continued when the migration is completed.

    return;

  }

  MOZ_ASSERT(mState == eActive);

  if (mOwningEventTarget->IsOnCurrentThread()) {

    SendLengthNeeded();

    return;

  }

  RefPtr<LengthNeededRunnable> runnable = new LengthNeededRunnable(this);

  mOwningEventTarget->Dispatch(runnable.forget(), NS_DISPATCH_NORMAL);

}

mozilla::ipc::IPCResult

IPCBlobInputStreamChild::RecvLengthReady(const int64_t& aLength)

{

  RefPtr<IPCBlobInputStream> pendingStream;

  nsCOMPtr<nsIEventTarget> eventTarget;

  {

    MutexAutoLock lock(mMutex);

    // We have been shutdown in the meantime.

    if (mState == eInactive) {

      return IPC_OK();

    }

    MOZ_ASSERT(!mPendingOperations.IsEmpty());

    MOZ_ASSERT(mState == eActive);

    pendingStream = mPendingOperations[0].mStream;

    eventTarget = mPendingOperations[0].mEventTarget;

    MOZ_ASSERT(mPendingOperations[0].mOp == PendingOperation::eLengthNeeded);

    mPendingOperations.RemoveElementAt(0);

  }

  RefPtr<LengthReadyRunnable> runnable =

    new LengthReadyRunnable(pendingStream, aLength);

   MOZ_ASSERT(eventTarget);

  eventTarget->Dispatch(runnable, NS_DISPATCH_NORMAL);

  return IPC_OK();

}

void

IPCBlobInputStreamChild::Migrated()

{

  MutexAutoLock lock(mMutex);

  MOZ_ASSERT(mState == eInactiveMigrating);

  mWorkerRef = nullptr;

  mOwningEventTarget = GetCurrentThreadSerialEventTarget();

  MOZ_ASSERT(IPCBlobInputStreamThread::IsOnFileEventTarget(mOwningEventTarget));

  // Maybe we have no reasons to keep this actor alive.

  if (mStreams.IsEmpty()) {

    mState = eInactive;

    SendClose();

    return;

  }

  mState = eActive;

  // Let's processing the pending operations. We need a stream for each pending

  // operation.

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

    if (mPendingOperations[i].mOp == PendingOperation::eStreamNeeded) {

      SendStreamNeeded();

    } else {

      MOZ_ASSERT(mPendingOperations[i].mOp == PendingOperation::eLengthNeeded);

      SendLengthNeeded();

    }

  }

}

} // namespace dom

} // namespace mozilla