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