xpcom/ds/ArenaAllocatorExtensions.h
author Kris Maglione <maglione.k@gmail.com>
Thu, 10 May 2018 10:36:53 -0700
changeset 473641 1becc594554c1a273535ed175895e801667735e9
parent 439997 6bb54c25baf91492fcacdcea8b50256e0e4eb26f
child 505383 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1460600: Remove unsupported --enable-system-hunspell flag. r=glandium Our bundled Hunspell now significantly differs from upstream Hunspell. Most importantly, it supports loading dictionaries from jar: URIs, which is now a requirement for loading bundled and extension dictionaries. This means that system Hunspell libraries are no longer compatible with our spell checker code. We should remove the option to use them so that users don't fall into the trap of trying to use them. MozReview-Commit-ID: 2ihJe6YOnGf

/* -*- 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_ArenaAllocatorExtensions_h
#define mozilla_ArenaAllocatorExtensions_h

#include "mozilla/ArenaAllocator.h"
#include "mozilla/CheckedInt.h"
#include "nsAString.h"

/**
 * Extensions to the ArenaAllocator class.
 */
namespace mozilla {

namespace detail {

template<typename T, size_t ArenaSize, size_t Alignment>
T* DuplicateString(const T* aSrc, const CheckedInt<size_t>& aLen,
                   ArenaAllocator<ArenaSize, Alignment>& aArena);

} // namespace detail

/**
 * Makes an arena allocated null-terminated copy of the source string. The
 * source string must be null-terminated.
 *
 * @param aSrc String to copy.
 * @param aArena The arena to allocate the string copy out of.
 * @return An arena allocated null-terminated string.
 */
template<typename T, size_t ArenaSize, size_t Alignment>
T* ArenaStrdup(const T* aStr,
               ArenaAllocator<ArenaSize, Alignment>& aArena)
{
  return detail::DuplicateString(aStr, nsCharTraits<T>::length(aStr), aArena);
}

/**
 * Makes an arena allocated null-terminated copy of the source string.
 *
 * @param aSrc String to copy.
 * @param aArena The arena to allocate the string copy out of.
 * @return An arena allocated null-terminated string.
 */
template<typename T, size_t ArenaSize, size_t Alignment>
T* ArenaStrdup(const detail::nsTStringRepr<T>& aStr,
               ArenaAllocator<ArenaSize, Alignment>& aArena)
{
  return detail::DuplicateString(aStr.BeginReading(), aStr.Length(), aArena);
}

/**
 * Copies the source string and adds a null terminator. Source string does not
 * have to be null terminated.
 */
template<typename T, size_t ArenaSize, size_t Alignment>
T* detail::DuplicateString(const T* aSrc, const CheckedInt<size_t>& aLen,
                           ArenaAllocator<ArenaSize, Alignment>& aArena)
{
  const auto byteLen = (aLen + 1) * sizeof(T);
  if (!byteLen.isValid()) {
    return nullptr;
  }

  T* p = static_cast<T*>(aArena.Allocate(byteLen.value(), mozilla::fallible));
  if (p) {
    memcpy(p, aSrc, byteLen.value() - sizeof(T));
    p[aLen.value()] = T(0);
  }

  return p;
}

} // namespace mozilla

#endif // mozilla_ArenaAllocatorExtensions_h