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// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_TYPES_FIXED_ARRAY_H_
#define BASE_TYPES_FIXED_ARRAY_H_
#include <stddef.h>
#include <memory>
#include <type_traits>
#include "third_party/abseil-cpp/absl/container/fixed_array.h"
namespace base {
// `FixedArray` provides `absl::FixedArray` in Chromium, but when `T` is
// trivially-default-constructible, forces the no-default-value constructor to
// initialize the elements to `T()`, instead of leaving them uninitialized. This
// makes `base::FixedArray` behave like `std::vector` instead of `std::array`
// and avoids the risk of UB.
// Trivially-default-constructible case: no-value constructor should init
template <typename T,
size_t N = absl::kFixedArrayUseDefault,
typename A = std::allocator<T>,
typename = void>
class FixedArray : public absl::FixedArray<T, N, A> {
public:
using absl::FixedArray<T, N, A>::FixedArray;
explicit FixedArray(absl::FixedArray<T, N, A>::size_type n,
const absl::FixedArray<T, N, A>::allocator_type& a =
typename absl::FixedArray<T, N, A>::allocator_type())
: FixedArray(n, T(), a) {}
};
// Non-trivially-default-constructible case: Pass through all constructors
template <typename T, size_t N, typename A>
struct FixedArray<
T,
N,
A,
std::enable_if_t<!std::is_trivially_default_constructible_v<T>>>
: public absl::FixedArray<T, N, A> {
using absl::FixedArray<T, N, A>::FixedArray;
};
} // namespace base
#endif // BASE_TYPES_FIXED_ARRAY_H_
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