gecko-dev/dom/indexedDB/FileSnapshot.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 "FileSnapshot.h"

#include "IDBDatabase.h"
#include "IDBFileHandle.h"
#include "IDBMutableFile.h"
#include "mozilla/Assertions.h"
#include "mozilla/Mutex.h"
#include "nsIAsyncInputStream.h"
#include "nsICloneableInputStream.h"
#include "nsIIPCSerializableInputStream.h"

namespace mozilla {
namespace dom {
namespace indexedDB {

using namespace mozilla::ipc;

namespace {

class StreamWrapper final : public nsIAsyncInputStream,
                            public nsIInputStreamCallback,
                            public nsICloneableInputStream,
                            public nsIIPCSerializableInputStream {
  class CloseRunnable;

  nsCOMPtr<nsIEventTarget> mOwningThread;
  nsCOMPtr<nsIInputStream> mInputStream;
  RefPtr<IDBFileHandle> mFileHandle;
  bool mFinished;

  // This is needed to call OnInputStreamReady() with the correct inputStream.
  // It is protected by mutex.
  nsCOMPtr<nsIInputStreamCallback> mAsyncWaitCallback;

  Mutex mMutex;

 public:
  StreamWrapper(nsIInputStream* aInputStream, IDBFileHandle* aFileHandle)
      : mOwningThread(aFileHandle->GetMutableFile()->Database()->EventTarget()),
        mInputStream(aInputStream),
        mFileHandle(aFileHandle),
        mFinished(false),
        mMutex("StreamWrapper::mMutex") {
    AssertIsOnOwningThread();
    MOZ_ASSERT(aInputStream);
    MOZ_ASSERT(aFileHandle);
    aFileHandle->AssertIsOnOwningThread();

    mFileHandle->OnNewRequest();
  }

 private:
  virtual ~StreamWrapper();

  template <typename M>
  void SerializeInternal(InputStreamParams& aParams,
                         FileDescriptorArray& aFileDescriptors,
                         bool aDelayedStart, uint32_t aMaxSize,
                         uint32_t* aSizeUsed, M* aManager);

  bool IsOnOwningThread() const {
    MOZ_ASSERT(mOwningThread);

    bool current;
    return NS_SUCCEEDED(mOwningThread->IsOnCurrentThread(&current)) && current;
  }

  void AssertIsOnOwningThread() const { MOZ_ASSERT(IsOnOwningThread()); }

  void Finish() {
    AssertIsOnOwningThread();

    if (mFinished) {
      return;
    }

    mFinished = true;

    mFileHandle->OnRequestFinished(/* aActorDestroyedNormally */ true);
  }

  void Destroy() {
    if (IsOnOwningThread()) {
      delete this;
      return;
    }

    RefPtr<Runnable> destroyRunnable = NewNonOwningRunnableMethod(
        "StreamWrapper::Destroy", this, &StreamWrapper::Destroy);

    MOZ_ALWAYS_SUCCEEDS(
        mOwningThread->Dispatch(destroyRunnable, NS_DISPATCH_NORMAL));
  }

  bool IsCloneableInputStream() const {
    nsCOMPtr<nsICloneableInputStream> stream = do_QueryInterface(mInputStream);
    return !!stream;
  }

  bool IsIPCSerializableInputStream() const {
    nsCOMPtr<nsIIPCSerializableInputStream> stream =
        do_QueryInterface(mInputStream);
    return !!stream;
  }

  bool IsAsyncInputStream() const {
    nsCOMPtr<nsIAsyncInputStream> stream = do_QueryInterface(mInputStream);
    return !!stream;
  }

  NS_DECL_THREADSAFE_ISUPPORTS
  NS_DECL_NSIINPUTSTREAM
  NS_DECL_NSIASYNCINPUTSTREAM
  NS_DECL_NSIINPUTSTREAMCALLBACK
  NS_DECL_NSICLONEABLEINPUTSTREAM
  NS_DECL_NSIIPCSERIALIZABLEINPUTSTREAM
};

class StreamWrapper::CloseRunnable final : public Runnable {
  friend class StreamWrapper;

  RefPtr<StreamWrapper> mStreamWrapper;

 public:
  NS_INLINE_DECL_REFCOUNTING_INHERITED(CloseRunnable, Runnable)

 private:
  explicit CloseRunnable(StreamWrapper* aStreamWrapper)
      : Runnable("StreamWrapper::CloseRunnable"),
        mStreamWrapper(aStreamWrapper) {}

  ~CloseRunnable() = default;

  NS_IMETHOD
  Run() override;
};

}  // anonymous namespace

BlobImplSnapshot::BlobImplSnapshot(BlobImpl* aFileImpl,
                                   IDBFileHandle* aFileHandle)
    : mBlobImpl(aFileImpl) {
  MOZ_ASSERT(aFileImpl);
  MOZ_ASSERT(aFileHandle);

  mFileHandle =
      do_GetWeakReference(NS_ISUPPORTS_CAST(EventTarget*, aFileHandle));
}

BlobImplSnapshot::BlobImplSnapshot(BlobImpl* aFileImpl,
                                   nsIWeakReference* aFileHandle)
    : mBlobImpl(aFileImpl), mFileHandle(aFileHandle) {
  MOZ_ASSERT(aFileImpl);
  MOZ_ASSERT(aFileHandle);
}

NS_IMPL_ISUPPORTS_INHERITED(BlobImplSnapshot, BlobImpl, PIBlobImplSnapshot)

already_AddRefed<BlobImpl> BlobImplSnapshot::CreateSlice(
    uint64_t aStart, uint64_t aLength, const nsAString& aContentType,
    ErrorResult& aRv) {
  RefPtr<BlobImpl> blobImpl =
      mBlobImpl->CreateSlice(aStart, aLength, aContentType, aRv);

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

  blobImpl = new BlobImplSnapshot(blobImpl, mFileHandle);
  return blobImpl.forget();
}

void BlobImplSnapshot::CreateInputStream(nsIInputStream** aStream,
                                         ErrorResult& aRv) {
  nsCOMPtr<EventTarget> et = do_QueryReferent(mFileHandle);
  RefPtr<IDBFileHandle> fileHandle = static_cast<IDBFileHandle*>(et.get());
  if (!fileHandle || !fileHandle->IsOpen()) {
    aRv.Throw(NS_ERROR_DOM_FILEHANDLE_INACTIVE_ERR);
    return;
  }

  nsCOMPtr<nsIInputStream> stream;
  mBlobImpl->CreateInputStream(getter_AddRefs(stream), aRv);
  if (NS_WARN_IF(aRv.Failed())) {
    return;
  }

  RefPtr<StreamWrapper> wrapper = new StreamWrapper(stream, fileHandle);

  wrapper.forget(aStream);
}

BlobImpl* BlobImplSnapshot::GetBlobImpl() const {
  nsCOMPtr<EventTarget> et = do_QueryReferent(mFileHandle);
  RefPtr<IDBFileHandle> fileHandle = static_cast<IDBFileHandle*>(et.get());
  if (!fileHandle || !fileHandle->IsOpen()) {
    return nullptr;
  }

  return mBlobImpl;
}

void BlobImplSnapshot::GetBlobImplType(nsAString& aBlobImplType) const {
  aBlobImplType.AssignLiteral("BlobImplSnapshot[");

  nsAutoString blobImplType;
  mBlobImpl->GetBlobImplType(blobImplType);
  aBlobImplType.Append(blobImplType);

  aBlobImplType.AppendLiteral("]");
}

StreamWrapper::~StreamWrapper() {
  AssertIsOnOwningThread();

  Finish();
}

NS_IMPL_ADDREF(StreamWrapper)
NS_IMPL_RELEASE_WITH_DESTROY(StreamWrapper, Destroy())

NS_INTERFACE_MAP_BEGIN(StreamWrapper)
  NS_INTERFACE_MAP_ENTRY(nsIInputStream)
  NS_INTERFACE_MAP_ENTRY_CONDITIONAL(nsIAsyncInputStream, IsAsyncInputStream())
  NS_INTERFACE_MAP_ENTRY_CONDITIONAL(nsIInputStreamCallback,
                                     IsAsyncInputStream())
  NS_INTERFACE_MAP_ENTRY_CONDITIONAL(nsICloneableInputStream,
                                     IsCloneableInputStream())
  NS_INTERFACE_MAP_ENTRY_CONDITIONAL(nsIIPCSerializableInputStream,
                                     IsIPCSerializableInputStream())
  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIInputStream)
NS_INTERFACE_MAP_END

NS_IMETHODIMP
StreamWrapper::Close() {
  RefPtr<CloseRunnable> closeRunnable = new CloseRunnable(this);

  MOZ_ALWAYS_SUCCEEDS(
      mOwningThread->Dispatch(closeRunnable, NS_DISPATCH_NORMAL));

  return NS_OK;
}

NS_IMETHODIMP
StreamWrapper::Available(uint64_t* _retval) {
  return mInputStream->Available(_retval);
}

NS_IMETHODIMP
StreamWrapper::Read(char* aBuf, uint32_t aCount, uint32_t* _retval) {
  return mInputStream->Read(aBuf, aCount, _retval);
}

NS_IMETHODIMP
StreamWrapper::ReadSegments(nsWriteSegmentFun aWriter, void* aClosure,
                            uint32_t aCount, uint32_t* _retval) {
  return mInputStream->ReadSegments(aWriter, aClosure, aCount, _retval);
}

NS_IMETHODIMP
StreamWrapper::IsNonBlocking(bool* _retval) {
  return mInputStream->IsNonBlocking(_retval);
}

void StreamWrapper::Serialize(InputStreamParams& aParams,
                              FileDescriptorArray& aFileDescriptors,
                              bool aDelayedStart, uint32_t aMaxSize,
                              uint32_t* aSizeUsed, ContentChild* aManager) {
  SerializeInternal(aParams, aFileDescriptors, aDelayedStart, aMaxSize,
                    aSizeUsed, aManager);
}

void StreamWrapper::Serialize(InputStreamParams& aParams,
                              FileDescriptorArray& aFileDescriptors,
                              bool aDelayedStart, uint32_t aMaxSize,
                              uint32_t* aSizeUsed, PBackgroundChild* aManager) {
  SerializeInternal(aParams, aFileDescriptors, aDelayedStart, aMaxSize,
                    aSizeUsed, aManager);
}

void StreamWrapper::Serialize(InputStreamParams& aParams,
                              FileDescriptorArray& aFileDescriptors,
                              bool aDelayedStart, uint32_t aMaxSize,
                              uint32_t* aSizeUsed, ContentParent* aManager) {
  SerializeInternal(aParams, aFileDescriptors, aDelayedStart, aMaxSize,
                    aSizeUsed, aManager);
}

void StreamWrapper::Serialize(InputStreamParams& aParams,
                              FileDescriptorArray& aFileDescriptors,
                              bool aDelayedStart, uint32_t aMaxSize,
                              uint32_t* aSizeUsed,
                              PBackgroundParent* aManager) {
  SerializeInternal(aParams, aFileDescriptors, aDelayedStart, aMaxSize,
                    aSizeUsed, aManager);
}

template <typename M>
void StreamWrapper::SerializeInternal(InputStreamParams& aParams,
                                      FileDescriptorArray& aFileDescriptors,
                                      bool aDelayedStart, uint32_t aMaxSize,
                                      uint32_t* aSizeUsed, M* aManager) {
  MOZ_ASSERT(aSizeUsed);
  *aSizeUsed = 0;

  nsCOMPtr<nsIIPCSerializableInputStream> stream =
      do_QueryInterface(mInputStream);

  if (stream) {
    stream->Serialize(aParams, aFileDescriptors, aDelayedStart, aMaxSize,
                      aSizeUsed, aManager);
  }
}

bool StreamWrapper::Deserialize(const InputStreamParams& aParams,
                                const FileDescriptorArray& aFileDescriptors) {
  MOZ_CRASH("This method should never be called");
  return false;
}

NS_IMETHODIMP
StreamWrapper::CloseWithStatus(nsresult aStatus) {
  nsCOMPtr<nsIAsyncInputStream> stream = do_QueryInterface(mInputStream);
  if (!stream) {
    return NS_ERROR_NO_INTERFACE;
  }

  nsresult rv = stream->CloseWithStatus(aStatus);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  return Close();
}

NS_IMETHODIMP
StreamWrapper::AsyncWait(nsIInputStreamCallback* aCallback, uint32_t aFlags,
                         uint32_t aRequestedCount,
                         nsIEventTarget* aEventTarget) {
  nsCOMPtr<nsIAsyncInputStream> stream = do_QueryInterface(mInputStream);
  if (!stream) {
    return NS_ERROR_NO_INTERFACE;
  }

  nsCOMPtr<nsIInputStreamCallback> callback = aCallback ? this : nullptr;
  {
    MutexAutoLock lock(mMutex);

    if (mAsyncWaitCallback && aCallback) {
      return NS_ERROR_FAILURE;
    }

    mAsyncWaitCallback = aCallback;
  }

  return stream->AsyncWait(callback, aFlags, aRequestedCount, aEventTarget);
}

// nsIInputStreamCallback

NS_IMETHODIMP
StreamWrapper::OnInputStreamReady(nsIAsyncInputStream* aStream) {
  nsCOMPtr<nsIAsyncInputStream> stream = do_QueryInterface(mInputStream);
  if (!stream) {
    return NS_ERROR_NO_INTERFACE;
  }

  nsCOMPtr<nsIInputStreamCallback> callback;
  {
    MutexAutoLock lock(mMutex);

    // We have been canceled in the meanwhile.
    if (!mAsyncWaitCallback) {
      return NS_OK;
    }

    callback.swap(mAsyncWaitCallback);
  }

  MOZ_ASSERT(callback);
  return callback->OnInputStreamReady(this);
}

// nsICloneableInputStream

NS_IMETHODIMP
StreamWrapper::GetCloneable(bool* aCloneable) {
  nsCOMPtr<nsICloneableInputStream> stream = do_QueryInterface(mInputStream);
  if (!stream) {
    *aCloneable = false;
    return NS_ERROR_NO_INTERFACE;
  }

  return stream->GetCloneable(aCloneable);
}

NS_IMETHODIMP
StreamWrapper::Clone(nsIInputStream** aResult) {
  nsCOMPtr<nsICloneableInputStream> stream = do_QueryInterface(mInputStream);
  if (!stream) {
    return NS_ERROR_NO_INTERFACE;
  }

  return stream->Clone(aResult);
}

NS_IMETHODIMP
StreamWrapper::CloseRunnable::Run() {
  mStreamWrapper->Finish();

  return NS_OK;
}

}  // namespace indexedDB
}  // namespace dom
}  // namespace mozilla