Add QuicLRUCache.

net/quic/platform/api/quic_lru_cache_test.cc

+// Copyright (c) 2016 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 "net/quic/platform/api/quic_lru_cache.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace net {
+namespace test {
+namespace {
+
+struct CachedItem {
+  explicit CachedItem(uint32_t new_value) : value(new_value) {}
+
+  uint32_t value;
+};
+
+TEST(QuicLRUCacheTest, InsertAndLookup) {
+  QuicLRUCache<int, CachedItem> cache(5);
+  EXPECT_EQ(nullptr, cache.Lookup(1));
+  EXPECT_EQ(0u, cache.Size());
+  EXPECT_EQ(5u, cache.MaxSize());
+
+  // Check that item 1 was properly inserted.
+  std::unique_ptr<CachedItem> item1(new CachedItem(11));
+  cache.Insert(1, std::move(item1));
+  EXPECT_EQ(1u, cache.Size());
+  EXPECT_EQ(11u, cache.Lookup(1)->value);
+
+  // Check that item 2 overrides item 1.
+  std::unique_ptr<CachedItem> item2(new CachedItem(12));
+  cache.Insert(1, std::move(item2));
+  EXPECT_EQ(1u, cache.Size());
+  EXPECT_EQ(12u, cache.Lookup(1)->value);
+
+  std::unique_ptr<CachedItem> item3(new CachedItem(13));
+  cache.Insert(3, std::move(item3));
+  EXPECT_EQ(2u, cache.Size());
+  EXPECT_EQ(13u, cache.Lookup(3)->value);
+
+  // No memory leakage.
+  cache.Clear();
+  EXPECT_EQ(0u, cache.Size());
+}
+
+TEST(QuicLRUCacheTest, Eviction) {
+  QuicLRUCache<int, CachedItem> cache(3);
+
+  for (size_t i = 1; i <= 4; ++i) {
+    std::unique_ptr<CachedItem> item(new CachedItem(10 + i));
+    cache.Insert(i, std::move(item));
+  }
+
+  EXPECT_EQ(3u, cache.Size());
+  EXPECT_EQ(3u, cache.MaxSize());
+
+  // Make sure item 1 is evicted.
+  EXPECT_EQ(nullptr, cache.Lookup(1));
+  EXPECT_EQ(14u, cache.Lookup(4)->value);
+
+  EXPECT_EQ(12u, cache.Lookup(2)->value);
+  std::unique_ptr<CachedItem> item5(new CachedItem(15));
+  cache.Insert(5, std::move(item5));
+  // Make sure item 3 is evicted.
+  EXPECT_EQ(nullptr, cache.Lookup(3));
+  EXPECT_EQ(15u, cache.Lookup(5)->value);
+
+  // No memory leakage.
+  cache.Clear();
+  EXPECT_EQ(0u, cache.Size());
+}
+
+}  // namespace
+}  // namespace test
+}  // namespace net