/* -*-  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/. */

#include "mozilla/devtools/ZeroCopyNSIOutputStream.h"

#include "mozilla/DebugOnly.h"

#include "mozilla/Unused.h"

namespace mozilla {

namespace devtools {

ZeroCopyNSIOutputStream::ZeroCopyNSIOutputStream(nsCOMPtr<nsIOutputStream>& out)

  : out(out)

  , result_(NS_OK)

  , amountUsed(0)

  , writtenCount(0)

{

  DebugOnly<bool> nonBlocking = false;

  MOZ_ASSERT(out->IsNonBlocking(&nonBlocking) == NS_OK);

  MOZ_ASSERT(!nonBlocking);

}

ZeroCopyNSIOutputStream::~ZeroCopyNSIOutputStream()

{

  if (!failed())

    Unused << NS_WARN_IF(NS_FAILED(writeBuffer()));

}

nsresult

ZeroCopyNSIOutputStream::writeBuffer()

{

  if (failed())

    return result_;

  if (amountUsed == 0)

    return NS_OK;

  int32_t amountWritten = 0;

  while (amountWritten < amountUsed) {

    uint32_t justWritten = 0;

    result_ = out->Write(buffer + amountWritten,

                         amountUsed - amountWritten,

                         &justWritten);

    if (NS_WARN_IF(NS_FAILED(result_)))

      return result_;

    amountWritten += justWritten;

  }

  writtenCount += amountUsed;

  amountUsed = 0;

  return NS_OK;

}

// ZeroCopyOutputStream Interface

bool

ZeroCopyNSIOutputStream::Next(void** data, int* size)

{

  MOZ_ASSERT(data != nullptr);

  MOZ_ASSERT(size != nullptr);

  if (failed())

    return false;

  if (amountUsed == BUFFER_SIZE) {

    if (NS_FAILED(writeBuffer()))

      return false;

  }

  *data = buffer + amountUsed;

  *size = BUFFER_SIZE - amountUsed;

  amountUsed = BUFFER_SIZE;

  return true;

}

void

ZeroCopyNSIOutputStream::BackUp(int count)

{

  MOZ_ASSERT(count >= 0,

             "Cannot back up a negative amount of bytes.");

  MOZ_ASSERT(amountUsed == BUFFER_SIZE,

             "Can only call BackUp directly after calling Next.");

  MOZ_ASSERT(count <= amountUsed,

             "Can't back up further than we've given out.");

  amountUsed -= count;

}

::google::protobuf::int64

ZeroCopyNSIOutputStream::ByteCount() const

{

  return writtenCount + amountUsed;

}

} // namespace devtools

} // namespace mozilla