| // Copyright 2020 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "base/containers/checked_iterators.h" |
| |
| #include <algorithm> |
| #include <iterator> |
| |
| #include "base/check_op.h" |
| #include "base/debug/alias.h" |
| #include "base/ranges/algorithm.h" |
| #include "base/test/gtest_util.h" |
| #include "build/build_config.h" |
| #include "testing/gtest/include/gtest/gtest.h" |
| |
| namespace base { |
| |
| TEST(CheckedContiguousIterator, SatisfiesContiguousIteratorConcept) { |
| static_assert(std::contiguous_iterator<CheckedContiguousIterator<int>>); |
| } |
| |
| template <class T, size_t N> |
| constexpr CheckedContiguousConstIterator<T> MakeConstIter(T (&arr)[N], |
| size_t cur) { |
| // We allow cur == N as that makes a pointer at one-past-the-end which is |
| // considered part of the same allocation. |
| CHECK_LE(cur, N); |
| return |
| // SAFETY: `arr` has 1 element, `arr + 1` is considered a pointer into the |
| // same allocation, as it's one past the end. |
| UNSAFE_BUFFERS( |
| CheckedContiguousConstIterator<T>(arr, arr + cur, arr + N)); |
| } |
| |
| template <class T, size_t N> |
| constexpr CheckedContiguousIterator<T> MakeIter(T (&arr)[N], size_t cur) { |
| // We allow cur == N as that makes a pointer at one-past-the-end which is |
| // considered part of the same allocation. |
| CHECK_LE(cur, N); |
| return |
| // SAFETY: `arr` has 1 element, `arr + 1` is considered a pointer into the |
| // same allocation, as it's one past the end. |
| UNSAFE_BUFFERS(CheckedContiguousIterator<T>(arr, arr + cur, arr + N)); |
| } |
| |
| // Checks that constexpr CheckedContiguousConstIterators can be compared at |
| // compile time. |
| TEST(CheckedContiguousIterator, StaticComparisonOperators) { |
| static constexpr int arr[] = {0}; |
| |
| constexpr CheckedContiguousConstIterator<int> begin = MakeConstIter(arr, 0u); |
| constexpr CheckedContiguousConstIterator<int> end = MakeConstIter(arr, 1u); |
| |
| static_assert(begin == begin); |
| static_assert(end == end); |
| |
| static_assert(begin != end); |
| static_assert(end != begin); |
| |
| static_assert(begin < end); |
| |
| static_assert(begin <= begin); |
| static_assert(begin <= end); |
| static_assert(end <= end); |
| |
| static_assert(end > begin); |
| |
| static_assert(end >= end); |
| static_assert(end >= begin); |
| static_assert(begin >= begin); |
| } |
| |
| // Checks that comparison between iterators and const iterators works in both |
| // directions. |
| TEST(CheckedContiguousIterator, ConvertingComparisonOperators) { |
| static int arr[] = {0}; |
| |
| CheckedContiguousIterator<int> begin = MakeIter(arr, 0u); |
| CheckedContiguousConstIterator<int> cbegin = MakeConstIter(arr, 0u); |
| |
| CheckedContiguousIterator<int> end = MakeIter(arr, 1u); |
| CheckedContiguousConstIterator<int> cend = MakeConstIter(arr, 1u); |
| |
| EXPECT_EQ(begin, cbegin); |
| EXPECT_EQ(cbegin, begin); |
| EXPECT_EQ(end, cend); |
| EXPECT_EQ(cend, end); |
| |
| EXPECT_NE(begin, cend); |
| EXPECT_NE(cbegin, end); |
| EXPECT_NE(end, cbegin); |
| EXPECT_NE(cend, begin); |
| |
| EXPECT_LT(begin, cend); |
| EXPECT_LT(cbegin, end); |
| |
| EXPECT_LE(begin, cbegin); |
| EXPECT_LE(cbegin, begin); |
| EXPECT_LE(begin, cend); |
| EXPECT_LE(cbegin, end); |
| EXPECT_LE(end, cend); |
| EXPECT_LE(cend, end); |
| |
| EXPECT_GT(end, cbegin); |
| EXPECT_GT(cend, begin); |
| |
| EXPECT_GE(end, cend); |
| EXPECT_GE(cend, end); |
| EXPECT_GE(end, cbegin); |
| EXPECT_GE(cend, begin); |
| EXPECT_GE(begin, cbegin); |
| EXPECT_GE(cbegin, begin); |
| } |
| |
| TEST(CheckedContiguousIteratorDeathTest, OutOfBounds) { |
| static int arr[] = {0, 1, 2}; |
| |
| CheckedContiguousIterator<int> it = MakeIter(arr, 1u); |
| |
| EXPECT_CHECK_DEATH(base::debug::Alias(&it[-2])); |
| EXPECT_EQ(it[-1], 0); |
| EXPECT_EQ(it[0], 1); |
| EXPECT_EQ(it[1], 2); |
| EXPECT_CHECK_DEATH(base::debug::Alias(&it[3])); |
| |
| it += 2; // At [3], in bounds (at end). |
| it -= 3; // At [0], in bounds. |
| it += 1; // Back to [1], in bounds. |
| |
| EXPECT_CHECK_DEATH({ |
| it -= 2; |
| base::debug::Alias(&it); |
| }); |
| EXPECT_CHECK_DEATH({ |
| it += 3; |
| base::debug::Alias(&it); |
| }); |
| EXPECT_CHECK_DEATH({ |
| auto o = it - 2; |
| base::debug::Alias(&o); |
| }); |
| EXPECT_CHECK_DEATH({ |
| auto o = it + 3; |
| base::debug::Alias(&o); |
| }); |
| |
| it++; // At [2], in bounds. |
| ++it; // At [3], in bounds (at end). |
| EXPECT_CHECK_DEATH({ |
| ++it; |
| base::debug::Alias(&it); |
| }); |
| EXPECT_CHECK_DEATH({ |
| it++; |
| base::debug::Alias(&it); |
| }); |
| |
| it -= 3; // At [0], in bounds. |
| EXPECT_CHECK_DEATH({ |
| --it; |
| base::debug::Alias(&it); |
| }); |
| EXPECT_CHECK_DEATH({ |
| it--; |
| base::debug::Alias(&it); |
| }); |
| } |
| |
| } // namespace base |
| |
| namespace { |
| |
| // Helper template that wraps an iterator and disables its dereference and |
| // increment operations. |
| template <typename Iterator> |
| struct DisableDerefAndIncr : Iterator { |
| using Iterator::Iterator; |
| |
| // NOLINTNEXTLINE(google-explicit-constructor) |
| constexpr DisableDerefAndIncr(const Iterator& iter) : Iterator(iter) {} |
| |
| void operator*() = delete; |
| void operator++() = delete; |
| void operator++(int) = delete; |
| }; |
| |
| } // namespace |
| |
| // Inherit `pointer_traits` specialization from the base class. |
| template <typename Iter> |
| struct std::pointer_traits<DisableDerefAndIncr<Iter>> |
| : ::std::pointer_traits<Iter> {}; |
| |
| namespace base { |
| |
| // Tests that using std::copy with CheckedContiguousIterator<int> results in an |
| // optimized code-path that does not invoke the iterator's dereference and |
| // increment operations, as expected in libc++. This fails to compile if |
| // std::copy is not optimized. |
| // NOTE: This test relies on implementation details of the STL and thus might |
| // break in the future during a libc++ roll. If this does happen, please reach |
| // out to memory-safety-dev@chromium.org to reevaluate whether this test will |
| // still be needed. |
| #if defined(_LIBCPP_VERSION) |
| TEST(CheckedContiguousIterator, OptimizedCopy) { |
| using Iter = DisableDerefAndIncr<CheckedContiguousIterator<int>>; |
| |
| int arr_in[5] = {1, 2, 3, 4, 5}; |
| int arr_out[5]; |
| |
| Iter in_begin = MakeIter(arr_in, 0u); |
| Iter in_end = MakeIter(arr_in, 5u); |
| Iter out_begin = MakeIter(arr_out, 0u); |
| Iter out_end = std::copy(in_begin, in_end, out_begin); |
| EXPECT_EQ(out_end, out_begin + (in_end - in_begin)); |
| |
| EXPECT_TRUE(ranges::equal(arr_in, arr_out)); |
| } |
| #endif // defined(_LIBCPP_VERSION) |
| |
| } // namespace base |