/* -*- 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/. */

#ifndef mozilla_dom_quota_MemoryOutputStream_h

#define mozilla_dom_quota_MemoryOutputStream_h

#include "nsIOutputStream.h"

namespace mozilla {

namespace dom {

namespace quota {

// An output stream so you can read your potentially-async input stream into

// a contiguous buffer in the form of an nsCString using NS_AsyncCopy.

// Back when streams were more synchronous and people didn't know blocking I/O

// was bad, if you wanted to read a stream into a flat buffer, you could use

// NS_ReadInputStreamToString/NS_ReadInputStreamToBuffer.  But those don't work

// with async streams. This can be used to replace hand-rolled Read/AsyncWait()

// loops.  Because you specify the expected size up front, the nsCString buffer

// is pre-allocated so wasteful reallocations can be avoided.  However,

// nsCString currently may over-allocate and this can be problematic on 32-bit

// windows until we're rid of that build configuration.

class MemoryOutputStream final

  : public nsIOutputStream

{

  nsCString mData;

  uint64_t mOffset;

public:

  static already_AddRefed<MemoryOutputStream>

  Create(uint64_t aSize);

  const nsCString&

  Data() const

  {

    return mData;

  }

private:

  MemoryOutputStream()

  : mOffset(0)

  { }

  virtual ~MemoryOutputStream()

  { }

  NS_DECL_THREADSAFE_ISUPPORTS

  NS_DECL_NSIOUTPUTSTREAM

};

} // namespace quota

} // namespace dom

} // namespace mozilla

#endif /* mozilla_dom_quota_MemoryOutputStream_h */