/* -*- 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 "nsScriptableInputStream.h"

#include "nsMemory.h"

#include "nsString.h"

NS_IMPL_ISUPPORTS(nsScriptableInputStream, nsIScriptableInputStream)

// nsIScriptableInputStream methods

NS_IMETHODIMP

nsScriptableInputStream::Close() {

  if (!mInputStream) {

    return NS_ERROR_NOT_INITIALIZED;

  }

  return mInputStream->Close();

}

NS_IMETHODIMP

nsScriptableInputStream::Init(nsIInputStream* aInputStream) {

  if (!aInputStream) {

    return NS_ERROR_NULL_POINTER;

  }

  mInputStream = aInputStream;

  return NS_OK;

}

NS_IMETHODIMP

nsScriptableInputStream::Available(uint64_t* aResult) {

  if (!mInputStream) {

    return NS_ERROR_NOT_INITIALIZED;

  }

  return mInputStream->Available(aResult);

}

NS_IMETHODIMP

nsScriptableInputStream::Read(uint32_t aCount, char** aResult) {

  nsresult rv = NS_OK;

  uint64_t count64 = 0;

  char* buffer = nullptr;

  if (!mInputStream) {

    return NS_ERROR_NOT_INITIALIZED;

  }

  rv = mInputStream->Available(&count64);

  if (NS_FAILED(rv)) {

    return rv;

  }

  // bug716556 - Ensure count+1 doesn't overflow

  uint32_t count =

      XPCOM_MIN((uint32_t)XPCOM_MIN<uint64_t>(count64, aCount), UINT32_MAX - 1);

  buffer = (char*)malloc(count + 1);  // make room for '\0'

  if (!buffer) {

    return NS_ERROR_OUT_OF_MEMORY;

  }

  rv = ReadHelper(buffer, count);

  if (NS_FAILED(rv)) {

    free(buffer);

    return rv;

  }

  buffer[count] = '\0';

  *aResult = buffer;

  return NS_OK;

}

NS_IMETHODIMP

nsScriptableInputStream::ReadBytes(uint32_t aCount, nsACString& aResult) {

  if (!mInputStream) {

    return NS_ERROR_NOT_INITIALIZED;

  }

  if (!aResult.SetLength(aCount, fallible)) {

    return NS_ERROR_OUT_OF_MEMORY;

  }

  MOZ_ASSERT(aResult.Length() == aCount);

  char* ptr = aResult.BeginWriting();

  nsresult rv = ReadHelper(ptr, aCount);

  if (NS_FAILED(rv)) {

    aResult.Truncate();

  }

  return rv;

}

nsresult nsScriptableInputStream::ReadHelper(char* aBuffer, uint32_t aCount) {

  uint32_t totalBytesRead = 0;

  while (1) {

    uint32_t bytesRead;

    nsresult rv = mInputStream->Read(aBuffer + totalBytesRead,

                                     aCount - totalBytesRead, &bytesRead);

    if (NS_FAILED(rv)) {

      return rv;

    }

    totalBytesRead += bytesRead;

    if (totalBytesRead == aCount) {

      break;

    }

    // If we have read zero bytes, we have hit EOF.

    if (bytesRead == 0) {

      return NS_ERROR_FAILURE;

    }

  }

  return NS_OK;

}

nsresult nsScriptableInputStream::Create(nsISupports* aOuter, REFNSIID aIID,

                                         void** aResult) {

  if (aOuter) {

    return NS_ERROR_NO_AGGREGATION;

  }

  RefPtr<nsScriptableInputStream> sis = new nsScriptableInputStream();

  return sis->QueryInterface(aIID, aResult);

}