//===- unittests/ADT/IListIteratorTest.cpp - ilist_iterator unit tests ----===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "llvm/ADT/simple_ilist.h"
#include "gtest/gtest.h"

using namespace llvm;

namespace {

struct Node : ilist_node<Node> {};

TEST(IListIteratorTest, DefaultConstructor) {
  simple_ilist<Node>::iterator I;
  simple_ilist<Node>::reverse_iterator RI;
  simple_ilist<Node>::const_iterator CI;
  simple_ilist<Node>::const_reverse_iterator CRI;
  EXPECT_EQ(nullptr, I.getNodePtr());
  EXPECT_EQ(nullptr, CI.getNodePtr());
  EXPECT_EQ(nullptr, RI.getNodePtr());
  EXPECT_EQ(nullptr, CRI.getNodePtr());
  EXPECT_EQ(I, I);
  EXPECT_EQ(I, CI);
  EXPECT_EQ(CI, I);
  EXPECT_EQ(CI, CI);
  EXPECT_EQ(RI, RI);
  EXPECT_EQ(RI, CRI);
  EXPECT_EQ(CRI, RI);
  EXPECT_EQ(CRI, CRI);
  EXPECT_EQ(I, RI.getReverse());
  EXPECT_EQ(RI, I.getReverse());
}

TEST(IListIteratorTest, Empty) {
  simple_ilist<Node> L;

  // Check iterators of L.
  EXPECT_EQ(L.begin(), L.end());
  EXPECT_EQ(L.rbegin(), L.rend());

  // Reverse of end should be rend (since the sentinel sits on both sides).
  EXPECT_EQ(L.end(), L.rend().getReverse());
  EXPECT_EQ(L.rend(), L.end().getReverse());

  // Iterators shouldn't match default constructors.
  simple_ilist<Node>::iterator I;
  simple_ilist<Node>::reverse_iterator RI;
  EXPECT_NE(I, L.begin());
  EXPECT_NE(I, L.end());
  EXPECT_NE(RI, L.rbegin());
  EXPECT_NE(RI, L.rend());
}

TEST(IListIteratorTest, OneNodeList) {
  simple_ilist<Node> L;
  Node A;
  L.insert(L.end(), A);

  // Check address of reference.
  EXPECT_EQ(&A, &*L.begin());
  EXPECT_EQ(&A, &*L.rbegin());

  // Check that the handle matches.
  EXPECT_EQ(L.rbegin().getNodePtr(), L.begin().getNodePtr());

  // Check iteration.
  EXPECT_EQ(L.end(), ++L.begin());
  EXPECT_EQ(L.begin(), --L.end());
  EXPECT_EQ(L.rend(), ++L.rbegin());
  EXPECT_EQ(L.rbegin(), --L.rend());

  // Check conversions.
  EXPECT_EQ(L.rbegin(), L.begin().getReverse());
  EXPECT_EQ(L.begin(), L.rbegin().getReverse());
}

TEST(IListIteratorTest, TwoNodeList) {
  simple_ilist<Node> L;
  Node A, B;
  L.insert(L.end(), A);
  L.insert(L.end(), B);

  // Check order.
  EXPECT_EQ(&A, &*L.begin());
  EXPECT_EQ(&B, &*++L.begin());
  EXPECT_EQ(L.end(), ++++L.begin());
  EXPECT_EQ(&B, &*L.rbegin());
  EXPECT_EQ(&A, &*++L.rbegin());
  EXPECT_EQ(L.rend(), ++++L.rbegin());

  // Check conversions.
  EXPECT_EQ(++L.rbegin(), L.begin().getReverse());
  EXPECT_EQ(L.rbegin(), (++L.begin()).getReverse());
  EXPECT_EQ(++L.begin(), L.rbegin().getReverse());
  EXPECT_EQ(L.begin(), (++L.rbegin()).getReverse());
}

TEST(IListIteratorTest, CheckEraseForward) {
  simple_ilist<Node> L;
  Node A, B;
  L.insert(L.end(), A);
  L.insert(L.end(), B);

  // Erase nodes.
  auto I = L.begin();
  EXPECT_EQ(&A, &*I);
  L.remove(*I++);
  EXPECT_EQ(&B, &*I);
  L.remove(*I++);
  EXPECT_EQ(L.end(), I);
}

TEST(IListIteratorTest, CheckEraseReverse) {
  simple_ilist<Node> L;
  Node A, B;
  L.insert(L.end(), A);
  L.insert(L.end(), B);

  // Erase nodes.
  auto RI = L.rbegin();
  EXPECT_EQ(&B, &*RI);
  L.remove(*RI++);
  EXPECT_EQ(&A, &*RI);
  L.remove(*RI++);
  EXPECT_EQ(L.rend(), RI);
}

TEST(IListIteratorTest, ReverseConstructor) {
  simple_ilist<Node> L;
  const simple_ilist<Node> &CL = L;
  Node A, B;
  L.insert(L.end(), A);
  L.insert(L.end(), B);

  // Save typing.
  typedef simple_ilist<Node>::iterator iterator;
  typedef simple_ilist<Node>::reverse_iterator reverse_iterator;
  typedef simple_ilist<Node>::const_iterator const_iterator;
  typedef simple_ilist<Node>::const_reverse_iterator const_reverse_iterator;

  // Check conversion values.
  EXPECT_EQ(L.begin(), iterator(L.rend()));
  EXPECT_EQ(++L.begin(), iterator(++L.rbegin()));
  EXPECT_EQ(L.end(), iterator(L.rbegin()));
  EXPECT_EQ(L.rbegin(), reverse_iterator(L.end()));
  EXPECT_EQ(++L.rbegin(), reverse_iterator(++L.begin()));
  EXPECT_EQ(L.rend(), reverse_iterator(L.begin()));

  // Check const iterator constructors.
  EXPECT_EQ(CL.begin(), const_iterator(L.rend()));
  EXPECT_EQ(CL.begin(), const_iterator(CL.rend()));
  EXPECT_EQ(CL.rbegin(), const_reverse_iterator(L.end()));
  EXPECT_EQ(CL.rbegin(), const_reverse_iterator(CL.end()));

  // Confirm lack of implicit conversions.
  static_assert(!std::is_convertible<iterator, reverse_iterator>::value,
                "unexpected implicit conversion");
  static_assert(!std::is_convertible<reverse_iterator, iterator>::value,
                "unexpected implicit conversion");
  static_assert(
      !std::is_convertible<const_iterator, const_reverse_iterator>::value,
      "unexpected implicit conversion");
  static_assert(
      !std::is_convertible<const_reverse_iterator, const_iterator>::value,
      "unexpected implicit conversion");
}

} // end namespace