/* -*- 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/dom/StructuredCloneBlob.h"

#include "js/StructuredClone.h"

#include "js/Utility.h"

#include "js/Wrapper.h"

#include "mozilla/dom/BlobImpl.h"

#include "mozilla/dom/StructuredCloneTags.h"

#include "mozilla/Maybe.h"

#include "mozilla/UniquePtr.h"

#include "xpcpublic.h"

namespace mozilla {

namespace dom {

StructuredCloneBlob::StructuredCloneBlob()

    : StructuredCloneHolder(CloningSupported, TransferringNotSupported,

                            StructuredCloneScope::DifferentProcess)

{}

StructuredCloneBlob::~StructuredCloneBlob()

{

  UnregisterWeakMemoryReporter(this);

}

/* static */ already_AddRefed<StructuredCloneBlob>

StructuredCloneBlob::Constructor(GlobalObject& aGlobal, JS::HandleValue aValue,

                                 JS::HandleObject aTargetGlobal,

                                 ErrorResult& aRv)

{

  JSContext* cx = aGlobal.Context();

  RefPtr<StructuredCloneBlob> holder = StructuredCloneBlob::Create();

  Maybe<JSAutoRealm> ar;

  JS::RootedValue value(cx, aValue);

  if (aTargetGlobal) {

    JS::RootedObject targetGlobal(cx, js::CheckedUnwrap(aTargetGlobal));

    if (!targetGlobal) {

      js::ReportAccessDenied(cx);

      aRv.NoteJSContextException(cx);

      return nullptr;

    }

    ar.emplace(cx, targetGlobal);

    if (!JS_WrapValue(cx, &value)) {

      aRv.NoteJSContextException(cx);

      return nullptr;

    }

  } else if (value.isObject()) {

    JS::RootedObject obj(cx, js::CheckedUnwrap(&value.toObject()));

    if (!obj) {

      js::ReportAccessDenied(cx);

      aRv.NoteJSContextException(cx);

      return nullptr;

    }

    ar.emplace(cx, obj);

    value = JS::ObjectValue(*obj);

  }

  holder->Write(cx, value, aRv);

  if (aRv.Failed()) {

    return nullptr;

  }

  return holder.forget();

}

void

StructuredCloneBlob::Deserialize(JSContext* aCx, JS::HandleObject aTargetScope,

                                      JS::MutableHandleValue aResult, ErrorResult& aRv)

{

  JS::RootedObject scope(aCx, js::CheckedUnwrap(aTargetScope));

  if (!scope) {

    js::ReportAccessDenied(aCx);

    aRv.NoteJSContextException(aCx);

    return;

  }

  {

    JSAutoRealm ar(aCx, scope);

    Read(xpc::NativeGlobal(scope), aCx, aResult, aRv);

    if (aRv.Failed()) {

      return;

    }

  }

  if (!JS_WrapValue(aCx, aResult)) {

    aResult.set(JS::UndefinedValue());

    aRv.NoteJSContextException(aCx);

  }

}

/* static */ JSObject*

StructuredCloneBlob::ReadStructuredClone(JSContext* aCx, JSStructuredCloneReader* aReader,

                                         StructuredCloneHolder* aHolder)

{

  JS::RootedObject obj(aCx);

  {

    RefPtr<StructuredCloneBlob> holder = StructuredCloneBlob::Create();

    if (!holder->ReadStructuredCloneInternal(aCx, aReader, aHolder) ||

        !holder->WrapObject(aCx, nullptr, &obj)) {

      return nullptr;

    }

  }

  return obj.get();

}

bool

StructuredCloneBlob::ReadStructuredCloneInternal(JSContext* aCx, JSStructuredCloneReader* aReader,

                                                 StructuredCloneHolder* aHolder)

{

  uint32_t length;

  uint32_t version;

  if (!JS_ReadUint32Pair(aReader, &length, &version)) {

    return false;

  }

  uint32_t blobOffset;

  uint32_t blobCount;

  if (!JS_ReadUint32Pair(aReader, &blobOffset, &blobCount)) {

    return false;

  }

  if (blobCount) {

#ifdef FUZZING

    if (blobOffset >= aHolder->BlobImpls().Length()) {

      return false;

    }

#endif

    BlobImpls().AppendElements(&aHolder->BlobImpls()[blobOffset], blobCount);

  }

  JSStructuredCloneData data(mStructuredCloneScope);

  while (length) {

    size_t size;

    char* buffer = data.AllocateBytes(length, &size);

    if (!buffer || !JS_ReadBytes(aReader, buffer, size)) {

      return false;

    }

    length -= size;

  }

  mBuffer = MakeUnique<JSAutoStructuredCloneBuffer>(mStructuredCloneScope,

                                                    &StructuredCloneHolder::sCallbacks,

                                                    this);

  mBuffer->adopt(std::move(data), version, &StructuredCloneHolder::sCallbacks);

  return true;

}

bool

StructuredCloneBlob::WriteStructuredClone(JSContext* aCx, JSStructuredCloneWriter* aWriter,

                                          StructuredCloneHolder* aHolder)

{

  auto& data = mBuffer->data();

  if (!JS_WriteUint32Pair(aWriter, SCTAG_DOM_STRUCTURED_CLONE_HOLDER, 0) ||

      !JS_WriteUint32Pair(aWriter, data.Size(), JS_STRUCTURED_CLONE_VERSION) ||

      !JS_WriteUint32Pair(aWriter, aHolder->BlobImpls().Length(), BlobImpls().Length())) {

    return false;

  }

  aHolder->BlobImpls().AppendElements(BlobImpls());

  return data.ForEachDataChunk([&](const char* aData, size_t aSize) {

      return JS_WriteBytes(aWriter, aData, aSize);

  });

}

bool

StructuredCloneBlob::WrapObject(JSContext* aCx, JS::HandleObject aGivenProto, JS::MutableHandleObject aResult)

{

    return StructuredCloneHolder_Binding::Wrap(aCx, this, aGivenProto, aResult);

}

NS_IMETHODIMP

StructuredCloneBlob::CollectReports(nsIHandleReportCallback* aHandleReport,

                                    nsISupports* aData, bool aAnonymize)

{

  MOZ_COLLECT_REPORT(

    "explicit/dom/structured-clone-holder", KIND_HEAP, UNITS_BYTES,

    MallocSizeOf(this) + SizeOfExcludingThis(MallocSizeOf),

    "Memory used by StructuredCloneHolder DOM objects.");

  return NS_OK;

}

NS_IMPL_ISUPPORTS(StructuredCloneBlob, nsIMemoryReporter)

} // namespace dom

} // namespace mozilla