| // Copyright (c) 2020 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "hash_table_base.h" |
| |
| #include "util/test/test.h" |
| |
| #include <algorithm> |
| #include <vector> |
| |
| // This unit-test is also used to illustrate how to use HashTableBase<> |
| // in a concrete way. Here, each node is a simple pointer to a Int class |
| // that wraps a simple integer, but also keeps tracks of |
| // construction/destruction steps in global counters. This is used by the |
| // test to verify that operations like copies or moves do not miss or |
| // create allocations/deallocations. |
| // |
| // Because the derived table HashTableTest owns all pointer objects, it |
| // needs to manually create/deallocate them in its destructor, copy/move |
| // constructors and operators, as well as insert()/erase()/clear() methods. |
| // |
| // Finally, iteration support is provided through const_iterator and |
| // begin(), end() methods, which are enough for range-based for loops. |
| // |
| |
| // A simple int wrapper class that can also count creation/destruction. |
| class Int { |
| public: |
| explicit Int(int x) : x_(x) { creation_counter++; } |
| |
| Int(const Int& other) : x_(other.x_) { creation_counter++; } |
| |
| ~Int() { destruction_counter++; } |
| |
| int& x() { return x_; } |
| const int& x() const { return x_; } |
| |
| size_t hash() const { return static_cast<size_t>(x_); } |
| |
| static void ResetCounters() { |
| creation_counter = 0; |
| destruction_counter = 0; |
| } |
| |
| int x_; |
| |
| static size_t creation_counter; |
| static size_t destruction_counter; |
| }; |
| |
| size_t Int::creation_counter; |
| size_t Int::destruction_counter; |
| |
| // A HashTableBase<> node type that contains a simple pointer to a Int value. |
| struct TestHashNode { |
| Int* int_ptr; |
| |
| bool is_null() const { return !int_ptr; } |
| bool is_tombstone() const { return int_ptr == &kTombstone; } |
| bool is_valid() const { return !is_null() && !is_tombstone(); } |
| size_t hash_value() const { return int_ptr->hash(); } |
| |
| static Int kTombstone; |
| }; |
| |
| // Value is irrelevant since only its address is used. |
| Int TestHashNode::kTombstone(-1); |
| |
| // TestHashTable derives a HashTableBase<> instantiation to demonstrate |
| // full uses of the template. This includes: |
| // |
| // - Storing a pointer in each node, and managing ownership of pointed |
| // objects explicitly in the destructor, copy/move constructor and |
| // operator, as well as insert() and erase() methods. |
| // |
| // - The internal pointed objects are Int instance, but the TestHashTable |
| // API masks that entirely, instead implementing a simple set of integers, |
| // including iteration support. |
| // |
| // Note that placing the integers directly in the nodes would be much easier, |
| // but would not allow demonstrating how to manage ownership in thedestructor |
| class TestHashTable : public HashTableBase<TestHashNode> { |
| public: |
| using BaseType = HashTableBase<TestHashNode>; |
| using Node = BaseType::Node; |
| |
| static_assert(std::is_same<Node, TestHashNode>::value, |
| "HashTableBase<>::Node is not defined properly!"); |
| |
| BaseType& asBaseType() { return *this; } |
| const BaseType& asBaseType() const { return *this; } |
| |
| TestHashTable() = default; |
| |
| // IMPORTANT NOTE: Because the table contains bare owning pointers, we |
| // have to use explicit copy and move constructor/operators for things |
| // to work as expected. This is yet another reason why HashTableBase<> |
| // should only be used with care (preferrably with non-owning pointers). |
| // |
| TestHashTable(const TestHashTable& other) : BaseType(other) { |
| // Only node (i.e. pointers) are copied by the base type. |
| for (Node& node : ValidNodesRange()) { |
| node.int_ptr = new Int(*node.int_ptr); |
| } |
| } |
| |
| TestHashTable& operator=(const TestHashTable& other) { |
| if (this != &other) { |
| this->~TestHashTable(); |
| new (this) TestHashTable(other); |
| } |
| return *this; |
| } |
| |
| TestHashTable(TestHashTable&& other) noexcept : BaseType(std::move(other)) {} |
| TestHashTable& operator=(TestHashTable&& other) noexcept { |
| if (this != &other) { |
| this->~TestHashTable(); |
| new (this) TestHashTable(std::move(other)); |
| } |
| return *this; |
| } |
| |
| ~TestHashTable() { |
| // Discard all valid Int pointers in the hash table. |
| for (Node& node : ValidNodesRange()) |
| delete node.int_ptr; |
| } |
| |
| // Return true iff the table contains |x|. |
| bool contains(int x) const { |
| size_t hash = static_cast<size_t>(x); |
| Node* node = NodeLookup( |
| hash, [&](const Node* node) { return node->int_ptr->x() == x; }); |
| return node->is_valid(); |
| } |
| |
| // Try to insert |x| in the table. Returns true on success, or false if |
| // the value was already in it. |
| bool insert(int x) { |
| size_t hash = static_cast<size_t>(x); |
| Node* node = NodeLookup( |
| hash, [&](const Node* node) { return node->int_ptr->x() == x; }); |
| if (node->is_valid()) |
| return false; |
| |
| node->int_ptr = new Int(x); |
| UpdateAfterInsert(); |
| return true; |
| } |
| |
| // Try to remove |x| from the table. Return true on success, or false |
| // if the value was not in it. |
| bool erase(int x) { |
| size_t hash = static_cast<size_t>(x); |
| Node* node = NodeLookup( |
| hash, [&](const Node* node) { return node->int_ptr->x() == x; }); |
| if (!node->is_valid()) |
| return false; |
| |
| delete node->int_ptr; |
| node->int_ptr = &TestHashNode::kTombstone; |
| UpdateAfterRemoval(); |
| return true; |
| } |
| |
| // Remove all items |
| void clear() { |
| // Remove all pointed objects, since NodeClear() will not do it. |
| for (Node& node : ValidNodesRange()) |
| delete node.int_ptr; |
| |
| NodeClear(); |
| } |
| |
| // Define const_iterator that point to the integer value instead of the node |
| // of the Int instance to completely hide these from this class' API. |
| struct const_iterator : public BaseType::NodeIterator { |
| const int& operator*() const { |
| return (this->BaseType::NodeIterator::operator*()).int_ptr->x(); |
| } |
| const int* operator->() const { return &(this->operator*()); } |
| }; |
| |
| const_iterator begin() const { return {BaseType::NodeBegin()}; } |
| |
| const_iterator end() const { return {BaseType::NodeEnd()}; } |
| }; |
| |
| TEST(HashTableBaseTest, Construction) { |
| Int::ResetCounters(); |
| { |
| TestHashTable table; |
| EXPECT_TRUE(table.empty()); |
| EXPECT_EQ(table.size(), 0u); |
| EXPECT_EQ(table.begin(), table.end()); |
| } |
| |
| // No item was created or destroyed. |
| EXPECT_EQ(Int::creation_counter, 0u); |
| EXPECT_EQ(Int::destruction_counter, 0u); |
| } |
| |
| TEST(HashTableBaseTest, InsertionsAndLookups) { |
| Int::ResetCounters(); |
| { |
| TestHashTable table; |
| table.insert(1); |
| table.insert(5); |
| table.insert(7); |
| |
| EXPECT_FALSE(table.empty()); |
| EXPECT_EQ(table.size(), 3u); |
| EXPECT_NE(table.begin(), table.end()); |
| |
| EXPECT_EQ(Int::creation_counter, 3u); |
| EXPECT_EQ(Int::destruction_counter, 0u); |
| |
| EXPECT_FALSE(table.contains(0)); |
| EXPECT_TRUE(table.contains(1)); |
| EXPECT_FALSE(table.contains(2)); |
| EXPECT_FALSE(table.contains(3)); |
| EXPECT_TRUE(table.contains(5)); |
| EXPECT_FALSE(table.contains(6)); |
| EXPECT_TRUE(table.contains(7)); |
| EXPECT_FALSE(table.contains(8)); |
| } |
| |
| EXPECT_EQ(Int::creation_counter, 3u); |
| EXPECT_EQ(Int::destruction_counter, 3u); |
| } |
| |
| TEST(HashTableBaseTest, CopyAssignment) { |
| Int::ResetCounters(); |
| { |
| TestHashTable table; |
| table.insert(1); |
| table.insert(5); |
| table.insert(7); |
| |
| EXPECT_FALSE(table.empty()); |
| EXPECT_EQ(table.size(), 3u); |
| |
| TestHashTable table2; |
| EXPECT_TRUE(table2.empty()); |
| table2 = table; |
| EXPECT_FALSE(table2.empty()); |
| EXPECT_EQ(table2.size(), 3u); |
| EXPECT_FALSE(table.empty()); |
| EXPECT_EQ(table.size(), 3u); |
| |
| EXPECT_EQ(Int::creation_counter, 6u); |
| EXPECT_EQ(Int::destruction_counter, 0u); |
| |
| EXPECT_FALSE(table.contains(0)); |
| EXPECT_TRUE(table.contains(1)); |
| EXPECT_FALSE(table.contains(2)); |
| EXPECT_FALSE(table.contains(3)); |
| EXPECT_TRUE(table.contains(5)); |
| EXPECT_FALSE(table.contains(6)); |
| EXPECT_TRUE(table.contains(7)); |
| EXPECT_FALSE(table.contains(8)); |
| |
| EXPECT_FALSE(table2.contains(0)); |
| EXPECT_TRUE(table2.contains(1)); |
| EXPECT_FALSE(table2.contains(2)); |
| EXPECT_FALSE(table2.contains(3)); |
| EXPECT_TRUE(table2.contains(5)); |
| EXPECT_FALSE(table2.contains(6)); |
| EXPECT_TRUE(table2.contains(7)); |
| EXPECT_FALSE(table2.contains(8)); |
| } |
| |
| EXPECT_EQ(Int::creation_counter, 6u); |
| EXPECT_EQ(Int::destruction_counter, 6u); |
| } |
| |
| TEST(HashTableBaseTest, MoveAssignment) { |
| Int::ResetCounters(); |
| { |
| TestHashTable table; |
| table.insert(1); |
| table.insert(5); |
| table.insert(7); |
| |
| EXPECT_FALSE(table.empty()); |
| EXPECT_EQ(table.size(), 3u); |
| |
| TestHashTable table2; |
| EXPECT_TRUE(table2.empty()); |
| table2 = std::move(table); |
| EXPECT_FALSE(table2.empty()); |
| EXPECT_EQ(table2.size(), 3u); |
| EXPECT_TRUE(table.empty()); |
| EXPECT_EQ(table.size(), 0u); |
| |
| EXPECT_EQ(Int::creation_counter, 3u); |
| EXPECT_EQ(Int::destruction_counter, 0u); |
| |
| EXPECT_FALSE(table2.contains(0)); |
| EXPECT_TRUE(table2.contains(1)); |
| EXPECT_FALSE(table2.contains(2)); |
| EXPECT_FALSE(table2.contains(3)); |
| EXPECT_TRUE(table2.contains(5)); |
| EXPECT_FALSE(table2.contains(6)); |
| EXPECT_TRUE(table2.contains(7)); |
| EXPECT_FALSE(table2.contains(8)); |
| } |
| |
| EXPECT_EQ(Int::creation_counter, 3u); |
| EXPECT_EQ(Int::destruction_counter, 3u); |
| } |
| |
| TEST(HashTableBaseTest, Clear) { |
| Int::ResetCounters(); |
| { |
| TestHashTable table; |
| table.insert(1); |
| table.insert(5); |
| table.insert(7); |
| |
| EXPECT_FALSE(table.empty()); |
| EXPECT_EQ(table.size(), 3u); |
| |
| table.clear(); |
| EXPECT_TRUE(table.empty()); |
| |
| EXPECT_EQ(Int::creation_counter, 3u); |
| EXPECT_EQ(Int::destruction_counter, 3u); |
| } |
| |
| EXPECT_EQ(Int::creation_counter, 3u); |
| EXPECT_EQ(Int::destruction_counter, 3u); |
| } |
| |
| TEST(HashTableBaseTest, Iteration) { |
| TestHashTable table; |
| table.insert(1); |
| table.insert(5); |
| table.insert(7); |
| |
| EXPECT_FALSE(table.empty()); |
| EXPECT_EQ(table.size(), 3u); |
| |
| std::vector<int> values; |
| |
| for (const int& x : table) |
| values.push_back(x); |
| |
| std::sort(values.begin(), values.end()); |
| EXPECT_EQ(values.size(), 3u); |
| EXPECT_EQ(values[0], 1); |
| EXPECT_EQ(values[1], 5); |
| EXPECT_EQ(values[2], 7); |
| } |
