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// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/thumbnail/cc/scoped_ptr_expiring_cache.h"
#include <stddef.h>
#include <algorithm>
#include <vector>
#include "base/memory/ptr_util.h"
#include "base/memory/ref_counted.h"
#include "base/rand_util.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"
#define MAX_CACHE_SIZE 5u
namespace thumbnail {
namespace {
unsigned int GenerateValue(unsigned int key) {
return (key * key * 127) % 133 + key * 23;
}
class MockObject {
public:
static std::unique_ptr<MockObject> Create(unsigned int key) {
return base::WrapUnique(new MockObject(key));
}
MockObject(const MockObject&) = delete;
MockObject& operator=(const MockObject&) = delete;
unsigned int value() const { return value_; }
private:
explicit MockObject(unsigned int key) : value_(GenerateValue(key)) {}
unsigned int value_;
};
} // namespace
typedef testing::Test ScopedPtrExpiringCacheTest;
typedef ScopedPtrExpiringCache<unsigned int, MockObject>
TestScopedPtrExpiringCache;
TEST_F(ScopedPtrExpiringCacheTest, SimplePutAndGet) {
TestScopedPtrExpiringCache cache(MAX_CACHE_SIZE);
EXPECT_EQ(MAX_CACHE_SIZE, cache.MaximumCacheSize());
EXPECT_EQ(0u, cache.size());
for (unsigned int i = 0; i < MAX_CACHE_SIZE; i++) {
cache.Put(i, MockObject::Create(i));
}
EXPECT_EQ(MAX_CACHE_SIZE, cache.size());
unsigned int next_key = MAX_CACHE_SIZE;
// One cache entry should have been evicted.
cache.Put(next_key, MockObject::Create(next_key));
EXPECT_EQ(MAX_CACHE_SIZE, cache.size());
size_t cached_count = 0;
for (unsigned int i = 0; i < MAX_CACHE_SIZE + 1; i++) {
if (cache.Get(i)) {
EXPECT_EQ(GenerateValue(i), cache.Get(i)->value());
cached_count++;
}
}
EXPECT_EQ(MAX_CACHE_SIZE, cached_count);
// Test Get as membership test.
cached_count = 0;
for (unsigned int i = 0; i < MAX_CACHE_SIZE + 1; i++) {
if (cache.Get(i)) {
cached_count++;
}
}
EXPECT_EQ(MAX_CACHE_SIZE, cached_count);
cache.Clear();
EXPECT_EQ(0u, cache.size());
for (unsigned int i = 0; i < MAX_CACHE_SIZE + 1; i++) {
EXPECT_EQ(nullptr, cache.Get(i));
}
}
// The eviction policy is least-recently-used, where we define used as insertion
// into the cache. We test that the first to be evicted is the first entry
// inserted into the cache.
TEST_F(ScopedPtrExpiringCacheTest, EvictedEntry) {
TestScopedPtrExpiringCache cache(MAX_CACHE_SIZE);
for (unsigned int i = 0; i < MAX_CACHE_SIZE; i++) {
cache.Put(i, MockObject::Create(i));
}
unsigned int next_key = MAX_CACHE_SIZE;
cache.Put(next_key, MockObject::Create(next_key));
EXPECT_EQ(MAX_CACHE_SIZE, cache.size());
EXPECT_EQ(GenerateValue(next_key), cache.Get(next_key)->value());
// The first inserted entry should have been evicted.
EXPECT_EQ(nullptr, cache.Get(0));
// The rest of the content should be present.
for (unsigned int i = 1; i < MAX_CACHE_SIZE; i++) {
EXPECT_TRUE(cache.Get(i) != nullptr);
}
next_key++;
// The first candidate to be evicted is the head of the iterator.
unsigned int head_key = cache.begin()->first;
EXPECT_TRUE(cache.Get(head_key) != nullptr);
cache.Put(next_key, MockObject::Create(next_key));
EXPECT_NE(cache.begin()->first, head_key);
EXPECT_EQ(nullptr, cache.Get(head_key));
}
TEST_F(ScopedPtrExpiringCacheTest, RetainedEntry) {
TestScopedPtrExpiringCache cache(MAX_CACHE_SIZE);
for (unsigned int i = 0; i < MAX_CACHE_SIZE; i++) {
cache.Put(i, MockObject::Create(i));
}
// Add (cache size - 1)-entries.
for (unsigned int i = 0; i < MAX_CACHE_SIZE; i++) {
EXPECT_TRUE(cache.Get(i) != nullptr);
}
for (unsigned int i = MAX_CACHE_SIZE; i < 2 * MAX_CACHE_SIZE - 1; i++) {
cache.Put(i, MockObject::Create(i));
}
EXPECT_EQ(MAX_CACHE_SIZE, cache.size());
for (unsigned int i = 0; i < MAX_CACHE_SIZE - 1; i++) {
EXPECT_EQ(nullptr, cache.Get(i));
}
// The only retained entry (from the first round of insertion) is the last to
// be inserted.
EXPECT_TRUE(cache.Get(MAX_CACHE_SIZE - 1) != nullptr);
}
// Test that the iterator order is the insertion order. The first element of
// the iterator is the oldest entry in the cache.
TEST_F(ScopedPtrExpiringCacheTest, Iterator) {
TestScopedPtrExpiringCache cache(MAX_CACHE_SIZE);
std::vector<unsigned int> test_keys;
for (unsigned int i = 0; i < MAX_CACHE_SIZE; i++) {
test_keys.push_back(i);
}
base::RandomShuffle(test_keys.begin(), test_keys.end());
for (unsigned int i = 0; i < MAX_CACHE_SIZE; i++) {
cache.Put(test_keys[i], MockObject::Create(test_keys[i]));
}
TestScopedPtrExpiringCache::iterator cache_iter = cache.begin();
std::vector<unsigned int>::iterator key_iter = test_keys.begin();
while (cache_iter != cache.end() && key_iter != test_keys.end()) {
EXPECT_EQ(cache_iter->first, *key_iter);
cache_iter++;
key_iter++;
}
}
} // namespace thumbnail
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