1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
3 /* This Source Code Form is subject to the terms of the Mozilla Public
4  * License, v. 2.0. If a copy of the MPL was not distributed with this
5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6 
7 /* Useful extensions to UniquePtr. */
8 
9 #ifndef mozilla_UniquePtrExtensions_h
10 #define mozilla_UniquePtrExtensions_h
11 
12 #include "mozilla/fallible.h"
13 #include "mozilla/UniquePtr.h"
14 
15 namespace mozilla {
16 
17 /**
18  * MakeUniqueFallible works exactly like MakeUnique, except that the memory
19  * allocation performed is done fallibly, i.e. it can return nullptr.
20  */
21 template <typename T, typename... Args>
MakeUniqueFallible(Args &&...aArgs)22 typename detail::UniqueSelector<T>::SingleObject MakeUniqueFallible(
23     Args&&... aArgs) {
24   return UniquePtr<T>(new (fallible) T(Forward<Args>(aArgs)...));
25 }
26 
27 template <typename T>
MakeUniqueFallible(decltype (sizeof (int))aN)28 typename detail::UniqueSelector<T>::UnknownBound MakeUniqueFallible(
29     decltype(sizeof(int)) aN) {
30   typedef typename RemoveExtent<T>::Type ArrayType;
31   return UniquePtr<T>(new (fallible) ArrayType[aN]());
32 }
33 
34 template <typename T, typename... Args>
35 typename detail::UniqueSelector<T>::KnownBound MakeUniqueFallible(
36     Args&&... aArgs) = delete;
37 
38 namespace detail {
39 
40 template <typename T>
41 struct FreePolicy {
operatorFreePolicy42   void operator()(const void* ptr) { free(const_cast<void*>(ptr)); }
43 };
44 
45 }  // namespace detail
46 
47 template <typename T>
48 using UniqueFreePtr = UniquePtr<T, detail::FreePolicy<T>>;
49 
50 }  // namespace mozilla
51 
52 #endif  // mozilla_UniquePtrExtensions_h
53