/* -*- Mode: C++; tab-width: 2; 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/. */

#ifndef PartiallySeekableInputStream_h

#define PartiallySeekableInputStream_h

#include "mozilla/Attributes.h"

#include "mozilla/Mutex.h"

#include "nsCOMPtr.h"

#include "nsIAsyncInputStream.h"

#include "nsICloneableInputStream.h"

#include "nsIInputStreamLength.h"

#include "nsIIPCSerializableInputStream.h"

#include "nsISeekableStream.h"

namespace mozilla {

namespace net {

// A wrapper for making a stream seekable for the first |aBufferSize| bytes.

// Note that this object takes the ownership of the underlying stream.

class PartiallySeekableInputStream final : public nsISeekableStream

                                         , public nsIAsyncInputStream

                                         , public nsICloneableInputStream

                                         , public nsIIPCSerializableInputStream

                                         , public nsIInputStreamCallback

                                         , public nsIInputStreamLength

                                         , public nsIAsyncInputStreamLength

                                         , public nsIInputStreamLengthCallback

{

public:

  NS_DECL_THREADSAFE_ISUPPORTS

  NS_DECL_NSIINPUTSTREAM

  NS_DECL_NSISEEKABLESTREAM

  NS_DECL_NSIASYNCINPUTSTREAM

  NS_DECL_NSICLONEABLEINPUTSTREAM

  NS_DECL_NSIIPCSERIALIZABLEINPUTSTREAM

  NS_DECL_NSIINPUTSTREAMCALLBACK

  NS_DECL_NSIINPUTSTREAMLENGTH

  NS_DECL_NSIASYNCINPUTSTREAMLENGTH

  NS_DECL_NSIINPUTSTREAMLENGTHCALLBACK

  explicit PartiallySeekableInputStream(already_AddRefed<nsIInputStream> aInputStream,

                                        uint64_t aBufferSize = 4096);

private:

  PartiallySeekableInputStream(already_AddRefed<nsIInputStream> aClonedBaseStream,

                               PartiallySeekableInputStream* aClonedFrom);

  ~PartiallySeekableInputStream() = default;

  void

  Init();

  nsCOMPtr<nsIInputStream> mInputStream;

  // Raw pointers because these are just QI of mInputStream.

  nsICloneableInputStream* mWeakCloneableInputStream;

  nsIIPCSerializableInputStream* mWeakIPCSerializableInputStream;

  nsIAsyncInputStream* mWeakAsyncInputStream;

  nsIInputStreamLength* mWeakInputStreamLength;

  nsIAsyncInputStreamLength* mWeakAsyncInputStreamLength;

  // Protected by mutex.

  nsCOMPtr<nsIInputStreamCallback> mAsyncWaitCallback;

  // Protected by mutex.

  nsCOMPtr<nsIInputStreamLengthCallback> mAsyncInputStreamLengthCallback;

  nsTArray<char> mCachedBuffer;

  uint64_t mBufferSize;

  uint64_t mPos;

  bool mClosed;

  Mutex mMutex;

};

} // net namespace

} // mozilla namespace

#endif // PartiallySeekableInputStream_h