IteratorTest.cpp File Reference

#include <algorithm>
#include <cassert>
#include <cstddef>
#include <deque>
#include <functional>
#include <map>
#include <set>
#include <tuple>
#include <type_traits>
#include <utility>
#include <vector>
#include <folly/container/Iterator.h>
#include <folly/portability/GTest.h>

Go to the source code of this file.

Functions
	TEST (EmplaceIterator, EmplacerTest)
	TEST (EmplaceIterator, FrontEmplacerTest)
	TEST (EmplaceIterator, BackEmplacerTest)
	TEST (EmplaceIterator, HintEmplacerTest)
	TEST (EmplaceIterator, Copy)
	TEST (EmplaceIterator, Transform)
	TEST (EmplaceIterator, EmplaceArgs)
	TEST (EmplaceIterator, ImplicitUnpack)

Function Documentation

TEST	(	EmplaceIterator	,
		EmplacerTest
	)

Basic tests for folly::emplace_iterator.

Definition at line 153 of file IteratorTest.cpp.

References copy_and_move_test(), folly::emplacer(), and EXPECT_EQ.

                                    {
  {
    Container<int> q;
    copy_and_move_test(q, emplacer(q, q.begin()));
  }
  {
    Container<Object> q;
    emplace_test(q, emplacer(q, q.begin()));
  }
  {
    Container<int> q;
    auto it = emplacer(q, q.begin());
    it = 0;
    it = 1;
    it = 2;
    it = emplacer(q, q.begin());
    it = 3;
    it = 4;
    EXPECT_EQ(q, Container<int>({3, 4, 0, 1, 2}));
  }
}

TEST	(	EmplaceIterator	,
		FrontEmplacerTest
	)

Basic tests for folly::front_emplace_iterator.

Definition at line 178 of file IteratorTest.cpp.

References copy_and_move_test(), EXPECT_EQ, and folly::front_emplacer().

                                         {
  {
    Container<int> q;
    copy_and_move_test(q, front_emplacer(q));
  }
  {
    Container<Object> q;
    emplace_test(q, front_emplacer(q));
  }
  {
    Container<int> q;
    auto it = front_emplacer(q);
    it = 0;
    it = 1;
    it = 2;
    it = front_emplacer(q);
    it = 3;
    it = 4;
    EXPECT_EQ(q, Container<int>({4, 3, 2, 1, 0}));
  }
}

TEST	(	EmplaceIterator	,
		BackEmplacerTest
	)

Basic tests for folly::back_emplace_iterator.

Definition at line 203 of file IteratorTest.cpp.

References folly::back_emplacer(), copy_and_move_test(), and EXPECT_EQ.

                                        {
  {
    Container<int> q;
    copy_and_move_test(q, back_emplacer(q));
  }
  {
    Container<Object> q;
    emplace_test(q, back_emplacer(q));
  }
  {
    Container<int> q;
    auto it = back_emplacer(q);
    it = 0;
    it = 1;
    it = 2;
    it = back_emplacer(q);
    it = 3;
    it = 4;
    EXPECT_EQ(q, Container<int>({0, 1, 2, 3, 4}));
  }
}

TEST	(	EmplaceIterator	,
		HintEmplacerTest
	)

Basic tests for folly::hint_emplace_iterator.

Definition at line 228 of file IteratorTest.cpp.

References ASSERT_EQ, diff(), EXPECT_EQ, folly::hint_emplacer(), i, m, folly::make_emplace_args(), folly::operator<(), and operator==().

                                        {
  {
    init_counters();
    std::map<int, Object> m;
    auto it = hint_emplacer(m, m.end());
    it = make_emplace_args(
        std::piecewise_construct,
        std::forward_as_tuple(0),
        std::forward_as_tuple(0));
    it = make_emplace_args(
        std::piecewise_construct,
        std::forward_as_tuple(1),
        std::forward_as_tuple(0, 0));
    it = make_emplace_args(
        std::piecewise_construct,
        std::forward_as_tuple(2),
        std::forward_as_tuple(Object{}));
    ASSERT_EQ(m.size(), 3);
    EXPECT_EQ(gDefaultCtrCnt, 1);
    EXPECT_EQ(gCopyCtrCnt, 0);
    EXPECT_EQ(gMoveCtrCnt, 1);
    EXPECT_EQ(gExplicitCtrCnt, 1);
    EXPECT_EQ(gMultiargCtrCnt, 1);
    EXPECT_EQ(gCopyOpCnt, 0);
    EXPECT_EQ(gMoveOpCnt, 0);
    EXPECT_EQ(gConvertOpCnt, 0);
  }
  {
    struct O {
      explicit O(int i_) : i(i_) {}
      bool operator<(const O& other) const {
        return i < other.i;
      }
      bool operator==(const O& other) const {
        return i == other.i;
      }
      int i;
    };
    std::vector<int> v1 = {0, 1, 2, 3, 4};
    std::vector<int> v2 = {0, 2, 4};
    std::set<O> diff;
    std::set_difference(
        v1.begin(),
        v1.end(),
        v2.begin(),
        v2.end(),
        hint_emplacer(diff, diff.end()));
    std::set<O> expected = {O(1), O(3)};
    ASSERT_EQ(diff, expected);
  }
}

TEST	(	EmplaceIterator	,
		Copy
	)

Test std::copy() with explicit conversion. This would not compile with a std::back_insert_iterator, because the constructor of Object that takes a single int is explicit.

Definition at line 285 of file IteratorTest.cpp.

References folly::back_emplacer(), folly::copy(), and EXPECT_EQ.

                            {
  init_counters();
  Container<int> in({0, 1, 2});
  Container<Object> out;
  std::copy(in.begin(), in.end(), back_emplacer(out));
  EXPECT_EQ(3, out.size());
  EXPECT_EQ(gDefaultCtrCnt, 0);
  EXPECT_EQ(gCopyCtrCnt, 0);
  EXPECT_EQ(gMoveCtrCnt, 0);
  EXPECT_EQ(gExplicitCtrCnt, 3);
  EXPECT_EQ(gMultiargCtrCnt, 0);
  EXPECT_EQ(gCopyOpCnt, 0);
  EXPECT_EQ(gMoveOpCnt, 0);
  EXPECT_EQ(gConvertOpCnt, 0);
}

TEST	(	EmplaceIterator	,
		Transform
	)

Test std::transform() with multi-argument constructors. This would require a temporary Object with std::back_insert_iterator.

Definition at line 305 of file IteratorTest.cpp.

References folly::back_emplacer(), EXPECT_EQ, i, folly::make_emplace_args(), and folly::pushmi::operators::transform.

                                 {
  init_counters();
  Container<int> in({0, 1, 2});
  Container<Object> out;
  std::transform(in.begin(), in.end(), back_emplacer(out), [](int i) {
    return make_emplace_args(i, i);
  });
  EXPECT_EQ(3, out.size());
  EXPECT_EQ(gDefaultCtrCnt, 0);
  EXPECT_EQ(gCopyCtrCnt, 0);
  EXPECT_EQ(gMoveCtrCnt, 0);
  EXPECT_EQ(gExplicitCtrCnt, 0);
  EXPECT_EQ(gMultiargCtrCnt, 3);
  EXPECT_EQ(gCopyOpCnt, 0);
  EXPECT_EQ(gMoveOpCnt, 0);
  EXPECT_EQ(gConvertOpCnt, 0);
}

TEST	(	EmplaceIterator	,
		EmplaceArgs
	)

Test multi-argument store and forward.

Definition at line 326 of file IteratorTest.cpp.

References EXPECT_EQ, folly::make_emplace_args(), folly::gen::move, folly::rref(), and value.

                                   {
  Object o1;
  const Object o2;
  Object& o3 = o1;
  const Object& o4 = o3;
  Object o5;

  {
    // Test copy construction.
    auto args = make_emplace_args(0, o1, o2, o3, o4, Object{}, std::cref(o2));
    init_counters();
    auto args2 = args;
    EXPECT_EQ(gDefaultCtrCnt, 0);
    EXPECT_EQ(gCopyCtrCnt, 5);
    EXPECT_EQ(gMoveCtrCnt, 0);
    EXPECT_EQ(gExplicitCtrCnt, 0);
    EXPECT_EQ(gMultiargCtrCnt, 0);
    EXPECT_EQ(gCopyOpCnt, 0);
    EXPECT_EQ(gMoveOpCnt, 0);
    EXPECT_EQ(gConvertOpCnt, 0);

    // Test copy assignment.
    init_counters();
    args = args2;
    EXPECT_EQ(gDefaultCtrCnt, 0);
    EXPECT_EQ(gCopyCtrCnt, 0);
    EXPECT_EQ(gMoveCtrCnt, 0);
    EXPECT_EQ(gExplicitCtrCnt, 0);
    EXPECT_EQ(gMultiargCtrCnt, 0);
    EXPECT_EQ(gCopyOpCnt, 5);
    EXPECT_EQ(gMoveOpCnt, 0);
    EXPECT_EQ(gConvertOpCnt, 0);
  }

  {
    // Test RVO.
    init_counters();
    auto args = make_emplace_args(
        0, o1, o2, o3, o4, Object{}, std::cref(o2), rref(std::move(o5)));
    EXPECT_EQ(gDefaultCtrCnt, 1);
    EXPECT_EQ(gCopyCtrCnt, 4);
    EXPECT_EQ(gMoveCtrCnt, 1);
    EXPECT_EQ(gExplicitCtrCnt, 0);
    EXPECT_EQ(gMultiargCtrCnt, 0);
    EXPECT_EQ(gCopyOpCnt, 0);
    EXPECT_EQ(gMoveOpCnt, 0);
    EXPECT_EQ(gConvertOpCnt, 0);

    // Test move construction.
    init_counters();
    auto args2 = std::move(args);
    EXPECT_EQ(gDefaultCtrCnt, 0);
    EXPECT_EQ(gCopyCtrCnt, 0);
    EXPECT_EQ(gMoveCtrCnt, 5);
    EXPECT_EQ(gExplicitCtrCnt, 0);
    EXPECT_EQ(gMultiargCtrCnt, 0);
    EXPECT_EQ(gCopyOpCnt, 0);
    EXPECT_EQ(gMoveOpCnt, 0);
    EXPECT_EQ(gConvertOpCnt, 0);

    // Test move assignment.
    init_counters();
    args = std::move(args2);
    EXPECT_EQ(gDefaultCtrCnt, 0);
    EXPECT_EQ(gCopyCtrCnt, 0);
    EXPECT_EQ(gMoveCtrCnt, 0);
    EXPECT_EQ(gExplicitCtrCnt, 0);
    EXPECT_EQ(gMultiargCtrCnt, 0);
    EXPECT_EQ(gCopyOpCnt, 0);
    EXPECT_EQ(gMoveOpCnt, 5);
    EXPECT_EQ(gConvertOpCnt, 0);

    // Make sure arguments are stored correctly. lvalues by reference, rvalues
    // by (moved) copy. Rvalues cannot be stored by reference because they may
    // refer to an expired temporary by the time they are accessed.
    static_assert(
        std::is_same<
            int,
            std::tuple_element_t<0, decltype(args)::storage_type>>::value,
        "");
    static_assert(
        std::is_same<
            Object,
            std::tuple_element_t<1, decltype(args)::storage_type>>::value,
        "");
    static_assert(
        std::is_same<
            Object,
            std::tuple_element_t<2, decltype(args)::storage_type>>::value,
        "");
    static_assert(
        std::is_same<
            Object,
            std::tuple_element_t<3, decltype(args)::storage_type>>::value,
        "");
    static_assert(
        std::is_same<
            Object,
            std::tuple_element_t<4, decltype(args)::storage_type>>::value,
        "");
    static_assert(
        std::is_same<
            Object,
            std::tuple_element_t<5, decltype(args)::storage_type>>::value,
        "");
    static_assert(
        std::is_same<
            std::reference_wrapper<const Object>,
            std::tuple_element_t<6, decltype(args)::storage_type>>::value,
        "");
    static_assert(
        std::is_same<
            rvalue_reference_wrapper<Object>,
            std::tuple_element_t<7, decltype(args)::storage_type>>::value,
        "");

    // Check whether args.get() restores the original argument type for
    // rvalue references to emplace_args.
    static_assert(
        std::is_same<int&&, decltype(get_emplace_arg<0>(std::move(args)))>::
            value,
        "");
    static_assert(
        std::is_same<Object&, decltype(get_emplace_arg<1>(std::move(args)))>::
            value,
        "");
    static_assert(
        std::is_same<
            const Object&,
            decltype(get_emplace_arg<2>(std::move(args)))>::value,
        "");
    static_assert(
        std::is_same<Object&, decltype(get_emplace_arg<3>(std::move(args)))>::
            value,
        "");
    static_assert(
        std::is_same<
            const Object&,
            decltype(get_emplace_arg<4>(std::move(args)))>::value,
        "");
    static_assert(
        std::is_same<Object&&, decltype(get_emplace_arg<5>(std::move(args)))>::
            value,
        "");
    static_assert(
        std::is_same<
            const Object&,
            decltype(get_emplace_arg<6>(std::move(args)))>::value,
        "");
    static_assert(
        std::is_same<Object&&, decltype(get_emplace_arg<7>(std::move(args)))>::
            value,
        "");

    // lvalue references to emplace_args should behave mostly like std::tuples.
    // Note that get_emplace_arg<7>(args) does not compile, because
    // folly::rvalue_reference_wrappers can only be unwrapped through an rvalue
    // reference.
    static_assert(
        std::is_same<int&, decltype(get_emplace_arg<0>(args))>::value, "");
    static_assert(
        std::is_same<Object&, decltype(get_emplace_arg<1>(args))>::value, "");
    static_assert(
        std::is_same<Object&, decltype(get_emplace_arg<2>(args))>::value, "");
    static_assert(
        std::is_same<Object&, decltype(get_emplace_arg<3>(args))>::value, "");
    static_assert(
        std::is_same<Object&, decltype(get_emplace_arg<4>(args))>::value, "");
    static_assert(
        std::is_same<Object&, decltype(get_emplace_arg<5>(args))>::value, "");
    static_assert(
        std::is_same<const Object&, decltype(get_emplace_arg<6>(args))>::value,
        "");
  }
}

TEST	(	EmplaceIterator	,
		ImplicitUnpack
	)

Test implicit unpacking.

Definition at line 505 of file IteratorTest.cpp.

References folly::back_emplacer(), folly::emplacer(), EXPECT_EQ, folly::front_emplacer(), std::tr1::make_tuple(), and test().

                                      {
  static std::size_t multiCtrCnt;
  static std::size_t pairCtrCnt;
  static std::size_t tupleCtrCnt;

  struct Object2 {
    Object2(int, int) {
      ++multiCtrCnt;
    }
    explicit Object2(const std::pair<int, int>&) {
      ++pairCtrCnt;
    }
    explicit Object2(const std::tuple<int, int>&) {
      ++tupleCtrCnt;
    }
  };

  auto test = [](auto&& it, bool expectUnpack) {
    multiCtrCnt = pairCtrCnt = tupleCtrCnt = 0;
    it = std::make_pair(0, 0);
    it = std::make_tuple(0, 0);
    if (expectUnpack) {
      EXPECT_EQ(multiCtrCnt, 2);
      EXPECT_EQ(pairCtrCnt, 0);
      EXPECT_EQ(tupleCtrCnt, 0);
    } else {
      EXPECT_EQ(multiCtrCnt, 0);
      EXPECT_EQ(pairCtrCnt, 1);
      EXPECT_EQ(tupleCtrCnt, 1);
    }
  };

  Container<Object2> q;

  test(emplacer(q, q.begin()), true);
  test(emplacer<false>(q, q.begin()), false);
  test(front_emplacer(q), true);
  test(front_emplacer<false>(q), false);
  test(back_emplacer(q), true);
  test(back_emplacer<false>(q), false);
}