gecko-dev/xpcom/io/NonBlockingAsyncInputStream.cpp

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 "NonBlockingAsyncInputStream.h"
#include "mozilla/ipc/InputStreamUtils.h"
#include "nsIAsyncInputStream.h"
#include "nsICloneableInputStream.h"
#include "nsIInputStream.h"
#include "nsIIPCSerializableInputStream.h"
#include "nsISeekableStream.h"
#include "nsStreamUtils.h"

namespace mozilla {

using namespace ipc;

class NonBlockingAsyncInputStream::AsyncWaitRunnable final
    : public CancelableRunnable {
  RefPtr<NonBlockingAsyncInputStream> mStream;
  nsCOMPtr<nsIInputStreamCallback> mCallback;

 public:
  AsyncWaitRunnable(NonBlockingAsyncInputStream* aStream,
                    nsIInputStreamCallback* aCallback)
      : CancelableRunnable("AsyncWaitRunnable"),
        mStream(aStream),
        mCallback(aCallback) {}

  NS_IMETHOD
  Run() override {
    mStream->RunAsyncWaitCallback(this, mCallback.forget());
    return NS_OK;
  }

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

NS_IMPL_ADDREF(NonBlockingAsyncInputStream);
NS_IMPL_RELEASE(NonBlockingAsyncInputStream);

NonBlockingAsyncInputStream::WaitClosureOnly::WaitClosureOnly(
    AsyncWaitRunnable* aRunnable, nsIEventTarget* aEventTarget)
    : mRunnable(aRunnable), mEventTarget(aEventTarget) {}

NS_INTERFACE_MAP_BEGIN(NonBlockingAsyncInputStream)
  NS_INTERFACE_MAP_ENTRY(nsIInputStream)
  NS_INTERFACE_MAP_ENTRY(nsIAsyncInputStream)
  NS_INTERFACE_MAP_ENTRY_CONDITIONAL(nsICloneableInputStream,
                                     mWeakCloneableInputStream)
  NS_INTERFACE_MAP_ENTRY_CONDITIONAL(nsIIPCSerializableInputStream,
                                     mWeakIPCSerializableInputStream)
  NS_INTERFACE_MAP_ENTRY_CONDITIONAL(nsISeekableStream,
                                     mWeakSeekableInputStream)
  NS_INTERFACE_MAP_ENTRY_CONDITIONAL(nsITellableStream,
                                     mWeakTellableInputStream)
  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIInputStream)
NS_INTERFACE_MAP_END

/* static */
nsresult NonBlockingAsyncInputStream::Create(
    already_AddRefed<nsIInputStream> aInputStream,
    nsIAsyncInputStream** aResult) {
  MOZ_DIAGNOSTIC_ASSERT(aResult);

  nsCOMPtr<nsIInputStream> inputStream = std::move(aInputStream);

  bool nonBlocking = false;
  nsresult rv = inputStream->IsNonBlocking(&nonBlocking);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  MOZ_DIAGNOSTIC_ASSERT(nonBlocking);

#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
  nsCOMPtr<nsIAsyncInputStream> asyncInputStream =
      do_QueryInterface(inputStream);
  MOZ_DIAGNOSTIC_ASSERT(!asyncInputStream);
#endif  // MOZ_DIAGNOSTIC_ASSERT_ENABLED

  RefPtr<NonBlockingAsyncInputStream> stream =
      new NonBlockingAsyncInputStream(inputStream.forget());

  stream.forget(aResult);
  return NS_OK;
}

NonBlockingAsyncInputStream::NonBlockingAsyncInputStream(
    already_AddRefed<nsIInputStream> aInputStream)
    : mInputStream(std::move(aInputStream)),
      mWeakCloneableInputStream(nullptr),
      mWeakIPCSerializableInputStream(nullptr),
      mWeakSeekableInputStream(nullptr),
      mWeakTellableInputStream(nullptr),
      mLock("NonBlockingAsyncInputStream::mLock"),
      mClosed(false) {
  MOZ_ASSERT(mInputStream);

  nsCOMPtr<nsICloneableInputStream> cloneableStream =
      do_QueryInterface(mInputStream);
  if (cloneableStream && SameCOMIdentity(mInputStream, cloneableStream)) {
    mWeakCloneableInputStream = cloneableStream;
  }

  nsCOMPtr<nsIIPCSerializableInputStream> serializableStream =
      do_QueryInterface(mInputStream);
  if (serializableStream && SameCOMIdentity(mInputStream, serializableStream)) {
    mWeakIPCSerializableInputStream = serializableStream;
  }

  nsCOMPtr<nsISeekableStream> seekableStream = do_QueryInterface(mInputStream);
  if (seekableStream && SameCOMIdentity(mInputStream, seekableStream)) {
    mWeakSeekableInputStream = seekableStream;
  }

  nsCOMPtr<nsITellableStream> tellableStream = do_QueryInterface(mInputStream);
  if (tellableStream && SameCOMIdentity(mInputStream, tellableStream)) {
    mWeakTellableInputStream = tellableStream;
  }
}

NonBlockingAsyncInputStream::~NonBlockingAsyncInputStream() = default;

NS_IMETHODIMP
NonBlockingAsyncInputStream::Close() {
  RefPtr<AsyncWaitRunnable> waitClosureOnlyRunnable;
  nsCOMPtr<nsIEventTarget> waitClosureOnlyEventTarget;

  {
    MutexAutoLock lock(mLock);

    if (mClosed) {
      // Here we could return NS_BASE_STREAM_CLOSED as well, but just to avoid
      // warning messages, let's make everybody happy with a NS_OK.
      return NS_OK;
    }

    mClosed = true;

    NS_ENSURE_STATE(mInputStream);
    nsresult rv = mInputStream->Close();
    if (NS_WARN_IF(NS_FAILED(rv))) {
      mWaitClosureOnly.reset();
      return rv;
    }

    // If we have a WaitClosureOnly runnable, it's time to use it.
    if (mWaitClosureOnly.isSome()) {
      waitClosureOnlyRunnable = std::move(mWaitClosureOnly->mRunnable);
      waitClosureOnlyEventTarget = std::move(mWaitClosureOnly->mEventTarget);

      mWaitClosureOnly.reset();

      // Now we want to dispatch the asyncWaitCallback.
      mAsyncWaitCallback = waitClosureOnlyRunnable;
    }
  }

  if (waitClosureOnlyRunnable) {
    if (waitClosureOnlyEventTarget) {
      waitClosureOnlyEventTarget->Dispatch(waitClosureOnlyRunnable,
                                           NS_DISPATCH_NORMAL);
    } else {
      waitClosureOnlyRunnable->Run();
    }
  }

  return NS_OK;
}

// nsIInputStream interface

NS_IMETHODIMP
NonBlockingAsyncInputStream::Available(uint64_t* aLength) {
  nsresult rv = mInputStream->Available(aLength);
  // Don't issue warnings for legal condition NS_BASE_STREAM_CLOSED.
  if (rv == NS_BASE_STREAM_CLOSED || NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  // Nothing more to read. Let's close the stream now.
  if (*aLength == 0) {
    MutexAutoLock lock(mLock);
    mInputStream->Close();
    mClosed = true;
    return NS_BASE_STREAM_CLOSED;
  }

  return NS_OK;
}

NS_IMETHODIMP
NonBlockingAsyncInputStream::StreamStatus() {
  return mInputStream->StreamStatus();
}

NS_IMETHODIMP
NonBlockingAsyncInputStream::Read(char* aBuffer, uint32_t aCount,
                                  uint32_t* aReadCount) {
  return mInputStream->Read(aBuffer, aCount, aReadCount);
}

namespace {

class MOZ_RAII ReadSegmentsData {
 public:
  ReadSegmentsData(NonBlockingAsyncInputStream* aStream,
                   nsWriteSegmentFun aFunc, void* aClosure)
      : mStream(aStream), mFunc(aFunc), mClosure(aClosure) {}

  NonBlockingAsyncInputStream* mStream;
  nsWriteSegmentFun mFunc;
  void* mClosure;
};

nsresult ReadSegmentsWriter(nsIInputStream* aInStream, void* aClosure,
                            const char* aFromSegment, uint32_t aToOffset,
                            uint32_t aCount, uint32_t* aWriteCount) {
  ReadSegmentsData* data = static_cast<ReadSegmentsData*>(aClosure);
  return data->mFunc(data->mStream, data->mClosure, aFromSegment, aToOffset,
                     aCount, aWriteCount);
}

}  // namespace

NS_IMETHODIMP
NonBlockingAsyncInputStream::ReadSegments(nsWriteSegmentFun aWriter,
                                          void* aClosure, uint32_t aCount,
                                          uint32_t* aResult) {
  ReadSegmentsData data(this, aWriter, aClosure);
  return mInputStream->ReadSegments(ReadSegmentsWriter, &data, aCount, aResult);
}

NS_IMETHODIMP
NonBlockingAsyncInputStream::IsNonBlocking(bool* aNonBlocking) {
  *aNonBlocking = true;
  return NS_OK;
}

// nsICloneableInputStream interface

NS_IMETHODIMP
NonBlockingAsyncInputStream::GetCloneable(bool* aCloneable) {
  NS_ENSURE_STATE(mWeakCloneableInputStream);
  return mWeakCloneableInputStream->GetCloneable(aCloneable);
}

NS_IMETHODIMP
NonBlockingAsyncInputStream::Clone(nsIInputStream** aResult) {
  NS_ENSURE_STATE(mWeakCloneableInputStream);

  nsCOMPtr<nsIInputStream> clonedStream;
  nsresult rv = mWeakCloneableInputStream->Clone(getter_AddRefs(clonedStream));
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  nsCOMPtr<nsIAsyncInputStream> asyncStream;
  rv = Create(clonedStream.forget(), getter_AddRefs(asyncStream));
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  asyncStream.forget(aResult);
  return NS_OK;
}

// nsIAsyncInputStream interface

NS_IMETHODIMP
NonBlockingAsyncInputStream::CloseWithStatus(nsresult aStatus) {
  return Close();
}

NS_IMETHODIMP
NonBlockingAsyncInputStream::AsyncWait(nsIInputStreamCallback* aCallback,
                                       uint32_t aFlags,
                                       uint32_t aRequestedCount,
                                       nsIEventTarget* aEventTarget) {
  RefPtr<AsyncWaitRunnable> runnable;
  {
    MutexAutoLock lock(mLock);

    mWaitClosureOnly.reset();
    mAsyncWaitCallback = nullptr;

    if (!aCallback) {
      // Canceling previous callbacks, which is done above.
      return NS_OK;
    }

    // Maybe the stream is already closed.
    if (!mClosed) {
      uint64_t length;
      nsresult rv = mInputStream->Available(&length);
      if (NS_SUCCEEDED(rv) && length == 0) {
        mInputStream->Close();
        mClosed = true;
      }
    }

    runnable = new AsyncWaitRunnable(this, aCallback);
    if ((aFlags & nsIAsyncInputStream::WAIT_CLOSURE_ONLY) && !mClosed) {
      mWaitClosureOnly.emplace(runnable, aEventTarget);
      return NS_OK;
    }

    mAsyncWaitCallback = runnable;
  }

  MOZ_ASSERT(runnable);

  if (aEventTarget) {
    return aEventTarget->Dispatch(runnable.forget());
  }

  return runnable->Run();
}

// nsIIPCSerializableInputStream

void NonBlockingAsyncInputStream::SerializedComplexity(
    uint32_t aMaxSize, uint32_t* aSizeUsed, uint32_t* aPipes,
    uint32_t* aTransferables) {
  InputStreamHelper::SerializedComplexity(mInputStream, aMaxSize, aSizeUsed,
                                          aPipes, aTransferables);
}

void NonBlockingAsyncInputStream::Serialize(
    mozilla::ipc::InputStreamParams& aParams, uint32_t aMaxSize,
    uint32_t* aSizeUsed) {
  MOZ_ASSERT(mWeakIPCSerializableInputStream);
  InputStreamHelper::SerializeInputStream(mInputStream, aParams, aMaxSize,
                                          aSizeUsed);
}

bool NonBlockingAsyncInputStream::Deserialize(
    const mozilla::ipc::InputStreamParams& aParams) {
  MOZ_CRASH("NonBlockingAsyncInputStream cannot be deserialized!");
  return true;
}

// nsISeekableStream

NS_IMETHODIMP
NonBlockingAsyncInputStream::Seek(int32_t aWhence, int64_t aOffset) {
  NS_ENSURE_STATE(mWeakSeekableInputStream);
  return mWeakSeekableInputStream->Seek(aWhence, aOffset);
}

NS_IMETHODIMP
NonBlockingAsyncInputStream::SetEOF() {
  NS_ENSURE_STATE(mWeakSeekableInputStream);
  return NS_ERROR_NOT_IMPLEMENTED;
}

// nsITellableStream

NS_IMETHODIMP
NonBlockingAsyncInputStream::Tell(int64_t* aResult) {
  NS_ENSURE_STATE(mWeakTellableInputStream);
  return mWeakTellableInputStream->Tell(aResult);
}

void NonBlockingAsyncInputStream::RunAsyncWaitCallback(
    NonBlockingAsyncInputStream::AsyncWaitRunnable* aRunnable,
    already_AddRefed<nsIInputStreamCallback> aCallback) {
  nsCOMPtr<nsIInputStreamCallback> callback = std::move(aCallback);

  {
    MutexAutoLock lock(mLock);
    if (mAsyncWaitCallback != aRunnable) {
      // The callback has been canceled in the meantime.
      return;
    }

    mAsyncWaitCallback = nullptr;
  }

  callback->OnInputStreamReady(this);
}

}  // namespace mozilla