| // Copyright 2016 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef THIRD_PARTY_BASE_PTR_UTIL_H_ |
| #define THIRD_PARTY_BASE_PTR_UTIL_H_ |
| |
| #include <memory> |
| #include <utility> |
| |
| namespace pdfium { |
| |
| // Helper to transfer ownership of a raw pointer to a std::unique_ptr<T>. |
| // Note that std::unique_ptr<T> has very different semantics from |
| // std::unique_ptr<T[]>: do not use this helper for array allocations. |
| template <typename T> |
| std::unique_ptr<T> WrapUnique(T* ptr) { |
| return std::unique_ptr<T>(ptr); |
| } |
| |
| namespace internal { |
| |
| template <typename T> |
| struct MakeUniqueResult { |
| using Scalar = std::unique_ptr<T>; |
| }; |
| |
| template <typename T> |
| struct MakeUniqueResult<T[]> { |
| using Array = std::unique_ptr<T[]>; |
| }; |
| |
| template <typename T, size_t N> |
| struct MakeUniqueResult<T[N]> { |
| using Invalid = void; |
| }; |
| |
| } // namespace internal |
| |
| // Helper to construct an object wrapped in a std::unique_ptr. This is an |
| // implementation of C++14's std::MakeUnique that can be used in Chrome. |
| // |
| // MakeUnique<T>(args) should be preferred over WrapUnique(new T(args)): bare |
| // calls to `new` should be treated with scrutiny. |
| // |
| // Usage: |
| // // ptr is a std::unique_ptr<std::string> |
| // auto ptr = MakeUnique<std::string>("hello world!"); |
| // |
| // // arr is a std::unique_ptr<int[]> |
| // auto arr = MakeUnique<int[]>(5); |
| |
| // Overload for non-array types. Arguments are forwarded to T's constructor. |
| template <typename T, typename... Args> |
| typename internal::MakeUniqueResult<T>::Scalar MakeUnique(Args&&... args) { |
| return std::unique_ptr<T>(new T(std::forward<Args>(args)...)); |
| } |
| |
| // Overload for array types of unknown bound, e.g. T[]. The array is allocated |
| // with `new T[n]()` and value-initialized: note that this is distinct from |
| // `new T[n]`, which default-initializes. |
| template <typename T> |
| typename internal::MakeUniqueResult<T>::Array MakeUnique(size_t size) { |
| return std::unique_ptr<T>(new typename std::remove_extent<T>::type[size]()); |
| } |
| |
| // Overload to reject array types of known bound, e.g. T[n]. |
| template <typename T, typename... Args> |
| typename internal::MakeUniqueResult<T>::Invalid MakeUnique(Args&&... args) = |
| delete; |
| |
| } // namespace pdfium |
| |
| #endif // THIRD_PARTY_BASE_PTR_UTIL_H_ |