mru_cache_unittest.cc 7.26 KB
Newer Older
gejun's avatar
gejun committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271
// Copyright (c) 2011 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 "base/basictypes.h"
#include "base/containers/mru_cache.h"
#include <gtest/gtest.h>

namespace {

int cached_item_live_count = 0;

struct CachedItem {
  CachedItem() : value(0) {
    cached_item_live_count++;
  }

  explicit CachedItem(int new_value) : value(new_value) {
    cached_item_live_count++;
  }

  explicit CachedItem(const CachedItem& other) : value(other.value) {
    cached_item_live_count++;
  }

  ~CachedItem() {
    cached_item_live_count--;
  }

  int value;
};

}  // namespace

TEST(MRUCacheTest, Basic) {
  typedef base::MRUCache<int, CachedItem> Cache;
  Cache cache(Cache::NO_AUTO_EVICT);

  // Check failure conditions
  {
    CachedItem test_item;
    EXPECT_TRUE(cache.Get(0) == cache.end());
    EXPECT_TRUE(cache.Peek(0) == cache.end());
  }

  static const int kItem1Key = 5;
  CachedItem item1(10);
  Cache::iterator inserted_item = cache.Put(kItem1Key, item1);
  EXPECT_EQ(1U, cache.size());

  // Check that item1 was properly inserted.
  {
    Cache::iterator found = cache.Get(kItem1Key);
    EXPECT_TRUE(inserted_item == cache.begin());
    EXPECT_TRUE(found != cache.end());

    found = cache.Peek(kItem1Key);
    EXPECT_TRUE(found != cache.end());

    EXPECT_EQ(kItem1Key, found->first);
    EXPECT_EQ(item1.value, found->second.value);
  }

  static const int kItem2Key = 7;
  CachedItem item2(12);
  cache.Put(kItem2Key, item2);
  EXPECT_EQ(2U, cache.size());

  // Check that item1 is the oldest since item2 was added afterwards.
  {
    Cache::reverse_iterator oldest = cache.rbegin();
    ASSERT_TRUE(oldest != cache.rend());
    EXPECT_EQ(kItem1Key, oldest->first);
    EXPECT_EQ(item1.value, oldest->second.value);
  }

  // Check that item1 is still accessible by key.
  {
    Cache::iterator test_item = cache.Get(kItem1Key);
    ASSERT_TRUE(test_item != cache.end());
    EXPECT_EQ(kItem1Key, test_item->first);
    EXPECT_EQ(item1.value, test_item->second.value);
  }

  // Check that retrieving item1 pushed item2 to oldest.
  {
    Cache::reverse_iterator oldest = cache.rbegin();
    ASSERT_TRUE(oldest != cache.rend());
    EXPECT_EQ(kItem2Key, oldest->first);
    EXPECT_EQ(item2.value, oldest->second.value);
  }

  // Remove the oldest item and check that item1 is now the only member.
  {
    Cache::reverse_iterator next = cache.Erase(cache.rbegin());

    EXPECT_EQ(1U, cache.size());

    EXPECT_TRUE(next == cache.rbegin());
    EXPECT_EQ(kItem1Key, next->first);
    EXPECT_EQ(item1.value, next->second.value);

    cache.Erase(cache.begin());
    EXPECT_EQ(0U, cache.size());
  }

  // Check that Clear() works properly.
  cache.Put(kItem1Key, item1);
  cache.Put(kItem2Key, item2);
  EXPECT_EQ(2U, cache.size());
  cache.Clear();
  EXPECT_EQ(0U, cache.size());
}

TEST(MRUCacheTest, GetVsPeek) {
  typedef base::MRUCache<int, CachedItem> Cache;
  Cache cache(Cache::NO_AUTO_EVICT);

  static const int kItem1Key = 1;
  CachedItem item1(10);
  cache.Put(kItem1Key, item1);

  static const int kItem2Key = 2;
  CachedItem item2(20);
  cache.Put(kItem2Key, item2);

  // This should do nothing since the size is bigger than the number of items.
  cache.ShrinkToSize(100);

  // Check that item1 starts out as oldest
  {
    Cache::reverse_iterator iter = cache.rbegin();
    ASSERT_TRUE(iter != cache.rend());
    EXPECT_EQ(kItem1Key, iter->first);
    EXPECT_EQ(item1.value, iter->second.value);
  }

  // Check that Peek doesn't change ordering
  {
    Cache::iterator peekiter = cache.Peek(kItem1Key);
    ASSERT_TRUE(peekiter != cache.end());

    Cache::reverse_iterator iter = cache.rbegin();
    ASSERT_TRUE(iter != cache.rend());
    EXPECT_EQ(kItem1Key, iter->first);
    EXPECT_EQ(item1.value, iter->second.value);
  }
}

TEST(MRUCacheTest, KeyReplacement) {
  typedef base::MRUCache<int, CachedItem> Cache;
  Cache cache(Cache::NO_AUTO_EVICT);

  static const int kItem1Key = 1;
  CachedItem item1(10);
  cache.Put(kItem1Key, item1);

  static const int kItem2Key = 2;
  CachedItem item2(20);
  cache.Put(kItem2Key, item2);

  static const int kItem3Key = 3;
  CachedItem item3(30);
  cache.Put(kItem3Key, item3);

  static const int kItem4Key = 4;
  CachedItem item4(40);
  cache.Put(kItem4Key, item4);

  CachedItem item5(50);
  cache.Put(kItem3Key, item5);

  EXPECT_EQ(4U, cache.size());
  for (int i = 0; i < 3; ++i) {
    Cache::reverse_iterator iter = cache.rbegin();
    ASSERT_TRUE(iter != cache.rend());
  }

  // Make it so only the most important element is there.
  cache.ShrinkToSize(1);

  Cache::iterator iter = cache.begin();
  EXPECT_EQ(kItem3Key, iter->first);
  EXPECT_EQ(item5.value, iter->second.value);
}

// Make sure that the owning version release its pointers properly.
TEST(MRUCacheTest, Owning) {
  typedef base::OwningMRUCache<int, CachedItem*> Cache;
  Cache cache(Cache::NO_AUTO_EVICT);

  int initial_count = cached_item_live_count;

  // First insert and item and then overwrite it.
  static const int kItem1Key = 1;
  cache.Put(kItem1Key, new CachedItem(20));
  cache.Put(kItem1Key, new CachedItem(22));

  // There should still be one item, and one extra live item.
  Cache::iterator iter = cache.Get(kItem1Key);
  EXPECT_EQ(1U, cache.size());
  EXPECT_TRUE(iter != cache.end());
  EXPECT_EQ(initial_count + 1, cached_item_live_count);

  // Now remove it.
  cache.Erase(cache.begin());
  EXPECT_EQ(initial_count, cached_item_live_count);

  // Now try another cache that goes out of scope to make sure its pointers
  // go away.
  {
    Cache cache2(Cache::NO_AUTO_EVICT);
    cache2.Put(1, new CachedItem(20));
    cache2.Put(2, new CachedItem(20));
  }

  // There should be no objects leaked.
  EXPECT_EQ(initial_count, cached_item_live_count);

  // Check that Clear() also frees things correctly.
  {
    Cache cache2(Cache::NO_AUTO_EVICT);
    cache2.Put(1, new CachedItem(20));
    cache2.Put(2, new CachedItem(20));
    EXPECT_EQ(initial_count + 2, cached_item_live_count);
    cache2.Clear();
    EXPECT_EQ(initial_count, cached_item_live_count);
  }
}

TEST(MRUCacheTest, AutoEvict) {
  typedef base::OwningMRUCache<int, CachedItem*> Cache;
  static const Cache::size_type kMaxSize = 3;

  int initial_count = cached_item_live_count;

  {
    Cache cache(kMaxSize);

    static const int kItem1Key = 1, kItem2Key = 2, kItem3Key = 3, kItem4Key = 4;
    cache.Put(kItem1Key, new CachedItem(20));
    cache.Put(kItem2Key, new CachedItem(21));
    cache.Put(kItem3Key, new CachedItem(22));
    cache.Put(kItem4Key, new CachedItem(23));

    // The cache should only have kMaxSize items in it even though we inserted
    // more.
    EXPECT_EQ(kMaxSize, cache.size());
  }

  // There should be no objects leaked.
  EXPECT_EQ(initial_count, cached_item_live_count);
}

TEST(MRUCacheTest, HashingMRUCache) {
  // Very simple test to make sure that the hashing cache works correctly.
  typedef base::HashingMRUCache<std::string, CachedItem> Cache;
  Cache cache(Cache::NO_AUTO_EVICT);

  CachedItem one(1);
  cache.Put("First", one);

  CachedItem two(2);
  cache.Put("Second", two);

  EXPECT_EQ(one.value, cache.Get("First")->second.value);
  EXPECT_EQ(two.value, cache.Get("Second")->second.value);
  cache.ShrinkToSize(1);
  EXPECT_EQ(two.value, cache.Get("Second")->second.value);
  EXPECT_TRUE(cache.Get("First") == cache.end());
}