mfbt/UniquePtrExtensions.h
author Dão Gottwald <dao@mozilla.com>
Wed, 20 Feb 2019 07:20:52 +0000
changeset 516104 b9fe883c6c1eb27d2e16aceba083b8081ec6f944
parent 508163 6f3709b3878117466168c40affa7bca0b60cf75b
permissions -rw-r--r--
Bug 1504766 - Let explicit Dark and Light themes ignore the Windows 10 setting for accent color in title bars. r=ntim,Gijs a=lizzard Differential Revision: https://phabricator.services.mozilla.com/D19764

/* -*- 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/. */

/* Useful extensions to UniquePtr. */

#ifndef mozilla_UniquePtrExtensions_h
#define mozilla_UniquePtrExtensions_h

#include "mozilla/fallible.h"
#include "mozilla/UniquePtr.h"

namespace mozilla {

/**
 * MakeUniqueFallible works exactly like MakeUnique, except that the memory
 * allocation performed is done fallibly, i.e. it can return nullptr.
 */
template <typename T, typename... Args>
typename detail::UniqueSelector<T>::SingleObject MakeUniqueFallible(
    Args&&... aArgs) {
  return UniquePtr<T>(new (fallible) T(std::forward<Args>(aArgs)...));
}

template <typename T>
typename detail::UniqueSelector<T>::UnknownBound MakeUniqueFallible(
    decltype(sizeof(int)) aN) {
  typedef typename RemoveExtent<T>::Type ArrayType;
  return UniquePtr<T>(new (fallible) ArrayType[aN]());
}

template <typename T, typename... Args>
typename detail::UniqueSelector<T>::KnownBound MakeUniqueFallible(
    Args&&... aArgs) = delete;

namespace detail {

template <typename T>
struct FreePolicy {
  void operator()(const void* ptr) { free(const_cast<void*>(ptr)); }
};

}  // namespace detail

template <typename T>
using UniqueFreePtr = UniquePtr<T, detail::FreePolicy<T>>;

}  // namespace mozilla

#endif  // mozilla_UniquePtrExtensions_h