//===- unittests/ADT/IListTest.cpp - ilist 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/ilist.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/ilist_node.h"
#include "gtest/gtest.h"
#include <ostream>

using namespace llvm;

namespace {

struct Node : ilist_node<Node> {
  int Value;

  Node() {}
  Node(int Value) : Value(Value) {}
  Node(const Node&) = default;
  ~Node() { Value = -1; }
};

TEST(IListTest, Basic) {
  ilist<Node> List;
  List.push_back(new Node(1));
  EXPECT_EQ(1, List.back().Value);
  EXPECT_EQ(nullptr, List.getPrevNode(List.back()));
  EXPECT_EQ(nullptr, List.getNextNode(List.back()));

  List.push_back(new Node(2));
  EXPECT_EQ(2, List.back().Value);
  EXPECT_EQ(2, List.getNextNode(List.front())->Value);
  EXPECT_EQ(1, List.getPrevNode(List.back())->Value);

  const ilist<Node> &ConstList = List;
  EXPECT_EQ(2, ConstList.back().Value);
  EXPECT_EQ(2, ConstList.getNextNode(ConstList.front())->Value);
  EXPECT_EQ(1, ConstList.getPrevNode(ConstList.back())->Value);
}

TEST(IListTest, cloneFrom) {
  Node L1Nodes[] = {Node(0), Node(1)};
  Node L2Nodes[] = {Node(0), Node(1)};
  ilist<Node> L1, L2, L3;

  // Build L1 from L1Nodes.
  L1.push_back(&L1Nodes[0]);
  L1.push_back(&L1Nodes[1]);

  // Build L2 from L2Nodes, based on L1 nodes.
  L2.cloneFrom(L1, [&](const Node &N) { return &L2Nodes[N.Value]; });

  // Add a node to L3 to be deleted, and then rebuild L3 by copying L1.
  L3.push_back(new Node(7));
  L3.cloneFrom(L1, [](const Node &N) { return new Node(N); });

  EXPECT_EQ(2u, L1.size());
  EXPECT_EQ(&L1Nodes[0], &L1.front());
  EXPECT_EQ(&L1Nodes[1], &L1.back());
  EXPECT_EQ(2u, L2.size());
  EXPECT_EQ(&L2Nodes[0], &L2.front());
  EXPECT_EQ(&L2Nodes[1], &L2.back());
  EXPECT_EQ(2u, L3.size());
  EXPECT_EQ(0, L3.front().Value);
  EXPECT_EQ(1, L3.back().Value);

  // Don't free nodes on the stack.
  L1.clearAndLeakNodesUnsafely();
  L2.clearAndLeakNodesUnsafely();
}

TEST(IListTest, SpliceOne) {
  ilist<Node> List;
  List.push_back(new Node(1));

  // The single-element splice operation supports noops.
  List.splice(List.begin(), List, List.begin());
  EXPECT_EQ(1u, List.size());
  EXPECT_EQ(1, List.front().Value);
  EXPECT_TRUE(std::next(List.begin()) == List.end());

  // Altenative noop. Move the first element behind itself.
  List.push_back(new Node(2));
  List.push_back(new Node(3));
  List.splice(std::next(List.begin()), List, List.begin());
  EXPECT_EQ(3u, List.size());
  EXPECT_EQ(1, List.front().Value);
  EXPECT_EQ(2, std::next(List.begin())->Value);
  EXPECT_EQ(3, List.back().Value);
}

TEST(IListTest, SpliceSwap) {
  ilist<Node> L;
  Node N0(0);
  Node N1(1);
  L.insert(L.end(), &N0);
  L.insert(L.end(), &N1);
  EXPECT_EQ(0, L.front().Value);
  EXPECT_EQ(1, L.back().Value);

  L.splice(L.begin(), L, ++L.begin());
  EXPECT_EQ(1, L.front().Value);
  EXPECT_EQ(0, L.back().Value);

  L.clearAndLeakNodesUnsafely();
}

TEST(IListTest, SpliceSwapOtherWay) {
  ilist<Node> L;
  Node N0(0);
  Node N1(1);
  L.insert(L.end(), &N0);
  L.insert(L.end(), &N1);
  EXPECT_EQ(0, L.front().Value);
  EXPECT_EQ(1, L.back().Value);

  L.splice(L.end(), L, L.begin());
  EXPECT_EQ(1, L.front().Value);
  EXPECT_EQ(0, L.back().Value);

  L.clearAndLeakNodesUnsafely();
}

TEST(IListTest, UnsafeClear) {
  ilist<Node> List;

  // Before even allocating a sentinel.
  List.clearAndLeakNodesUnsafely();
  EXPECT_EQ(0u, List.size());

  // Empty list with sentinel.
  ilist<Node>::iterator E = List.end();
  List.clearAndLeakNodesUnsafely();
  EXPECT_EQ(0u, List.size());
  // The sentinel shouldn't change.
  EXPECT_TRUE(E == List.end());

  // List with contents.
  List.push_back(new Node(1));
  ASSERT_EQ(1u, List.size());
  Node *N = &*List.begin();
  EXPECT_EQ(1, N->Value);
  List.clearAndLeakNodesUnsafely();
  EXPECT_EQ(0u, List.size());
  ASSERT_EQ(1, N->Value);
  delete N;

  // List is still functional.
  List.push_back(new Node(5));
  List.push_back(new Node(6));
  ASSERT_EQ(2u, List.size());
  EXPECT_EQ(5, List.front().Value);
  EXPECT_EQ(6, List.back().Value);
}

struct NodeWithCallback : ilist_node<NodeWithCallback> {
  int Value = 0;
  bool IsInList = false;
  bool WasTransferred = false;

  NodeWithCallback() = default;
  NodeWithCallback(int Value) : Value(Value) {}
  NodeWithCallback(const NodeWithCallback &) = delete;
};

} // end namespace

namespace llvm {
// These nodes are stack-allocated for testing purposes, so don't let the ilist
// own or delete them.
template <> struct ilist_alloc_traits<NodeWithCallback> {
  static void deleteNode(NodeWithCallback *) {}
};

template <> struct ilist_callback_traits<NodeWithCallback> {
  void addNodeToList(NodeWithCallback *N) { N->IsInList = true; }
  void removeNodeFromList(NodeWithCallback *N) { N->IsInList = false; }
  template <class Iterator>
  void transferNodesFromList(ilist_callback_traits &Other, Iterator First,
                             Iterator Last) {
    for (; First != Last; ++First) {
      First->WasTransferred = true;
      Other.removeNodeFromList(&*First);
      addNodeToList(&*First);
    }
  }
};
} // end namespace llvm

namespace {

TEST(IListTest, addNodeToList) {
  ilist<NodeWithCallback> L1, L2;
  NodeWithCallback N(7);
  ASSERT_FALSE(N.IsInList);
  ASSERT_FALSE(N.WasTransferred);

  L1.insert(L1.begin(), &N);
  ASSERT_EQ(1u, L1.size());
  ASSERT_EQ(&N, &L1.front());
  ASSERT_TRUE(N.IsInList);
  ASSERT_FALSE(N.WasTransferred);

  L2.splice(L2.end(), L1);
  ASSERT_EQ(&N, &L2.front());
  ASSERT_TRUE(N.IsInList);
  ASSERT_TRUE(N.WasTransferred);

  L1.remove(&N);
  ASSERT_EQ(0u, L1.size());
  ASSERT_FALSE(N.IsInList);
  ASSERT_TRUE(N.WasTransferred);
}

TEST(IListTest, sameListSplice) {
  NodeWithCallback N1(1);
  NodeWithCallback N2(2);
  ASSERT_FALSE(N1.WasTransferred);
  ASSERT_FALSE(N2.WasTransferred);

  ilist<NodeWithCallback> L1;
  L1.insert(L1.end(), &N1);
  L1.insert(L1.end(), &N2);
  ASSERT_EQ(2u, L1.size());
  ASSERT_EQ(&N1, &L1.front());
  ASSERT_FALSE(N1.WasTransferred);
  ASSERT_FALSE(N2.WasTransferred);

  // Swap the nodes with splice inside the same list. Check that we get the
  // transfer callback.
  L1.splice(L1.begin(), L1, std::next(L1.begin()), L1.end());
  ASSERT_EQ(2u, L1.size());
  ASSERT_EQ(&N1, &L1.back());
  ASSERT_EQ(&N2, &L1.front());
  ASSERT_FALSE(N1.WasTransferred);
  ASSERT_TRUE(N2.WasTransferred);
}

struct PrivateNode : private ilist_node<PrivateNode> {
  friend struct llvm::ilist_detail::NodeAccess;

  int Value = 0;

  PrivateNode() = default;
  PrivateNode(int Value) : Value(Value) {}
  PrivateNode(const PrivateNode &) = delete;
};

TEST(IListTest, privateNode) {
  // Instantiate various APIs to be sure they're callable when ilist_node is
  // inherited privately.
  ilist<PrivateNode> L;
  PrivateNode N(7);
  L.insert(L.begin(), &N);
  ++L.begin();
  (void)*L.begin();
  (void)(L.begin() == L.end());

  ilist<PrivateNode> L2;
  L2.splice(L2.end(), L);
  L2.remove(&N);
}

} // end namespace