1 // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file. See the AUTHORS file for names of contributors.
4
5 #include "leveldb/cache.h"
6
7 #include <vector>
8 #include "util/coding.h"
9 #include "util/testharness.h"
10
11 namespace leveldb {
12
13 // Conversions between numeric keys/values and the types expected by Cache.
EncodeKey(int k)14 static std::string EncodeKey(int k) {
15 std::string result;
16 PutFixed32(&result, k);
17 return result;
18 }
DecodeKey(const Slice & k)19 static int DecodeKey(const Slice& k) {
20 assert(k.size() == 4);
21 return DecodeFixed32(k.data());
22 }
EncodeValue(uintptr_t v)23 static void* EncodeValue(uintptr_t v) { return reinterpret_cast<void*>(v); }
DecodeValue(void * v)24 static int DecodeValue(void* v) { return reinterpret_cast<uintptr_t>(v); }
25
26 class CacheTest {
27 public:
28 static CacheTest* current_;
29
Deleter(const Slice & key,void * v)30 static void Deleter(const Slice& key, void* v) {
31 current_->deleted_keys_.push_back(DecodeKey(key));
32 current_->deleted_values_.push_back(DecodeValue(v));
33 }
34
35 static const int kCacheSize = 1000;
36 std::vector<int> deleted_keys_;
37 std::vector<int> deleted_values_;
38 Cache* cache_;
39
CacheTest()40 CacheTest() : cache_(NewLRUCache(kCacheSize)) {
41 current_ = this;
42 }
43
~CacheTest()44 ~CacheTest() {
45 delete cache_;
46 }
47
Lookup(int key)48 int Lookup(int key) {
49 Cache::Handle* handle = cache_->Lookup(EncodeKey(key));
50 const int r = (handle == NULL) ? -1 : DecodeValue(cache_->Value(handle));
51 if (handle != NULL) {
52 cache_->Release(handle);
53 }
54 return r;
55 }
56
Insert(int key,int value,int charge=1)57 void Insert(int key, int value, int charge = 1) {
58 cache_->Release(cache_->Insert(EncodeKey(key), EncodeValue(value), charge,
59 &CacheTest::Deleter));
60 }
61
Erase(int key)62 void Erase(int key) {
63 cache_->Erase(EncodeKey(key));
64 }
65 };
66 CacheTest* CacheTest::current_;
67
TEST(CacheTest,HitAndMiss)68 TEST(CacheTest, HitAndMiss) {
69 ASSERT_EQ(-1, Lookup(100));
70
71 Insert(100, 101);
72 ASSERT_EQ(101, Lookup(100));
73 ASSERT_EQ(-1, Lookup(200));
74 ASSERT_EQ(-1, Lookup(300));
75
76 Insert(200, 201);
77 ASSERT_EQ(101, Lookup(100));
78 ASSERT_EQ(201, Lookup(200));
79 ASSERT_EQ(-1, Lookup(300));
80
81 Insert(100, 102);
82 ASSERT_EQ(102, Lookup(100));
83 ASSERT_EQ(201, Lookup(200));
84 ASSERT_EQ(-1, Lookup(300));
85
86 ASSERT_EQ(1, deleted_keys_.size());
87 ASSERT_EQ(100, deleted_keys_[0]);
88 ASSERT_EQ(101, deleted_values_[0]);
89 }
90
TEST(CacheTest,Erase)91 TEST(CacheTest, Erase) {
92 Erase(200);
93 ASSERT_EQ(0, deleted_keys_.size());
94
95 Insert(100, 101);
96 Insert(200, 201);
97 Erase(100);
98 ASSERT_EQ(-1, Lookup(100));
99 ASSERT_EQ(201, Lookup(200));
100 ASSERT_EQ(1, deleted_keys_.size());
101 ASSERT_EQ(100, deleted_keys_[0]);
102 ASSERT_EQ(101, deleted_values_[0]);
103
104 Erase(100);
105 ASSERT_EQ(-1, Lookup(100));
106 ASSERT_EQ(201, Lookup(200));
107 ASSERT_EQ(1, deleted_keys_.size());
108 }
109
TEST(CacheTest,EntriesArePinned)110 TEST(CacheTest, EntriesArePinned) {
111 Insert(100, 101);
112 Cache::Handle* h1 = cache_->Lookup(EncodeKey(100));
113 ASSERT_EQ(101, DecodeValue(cache_->Value(h1)));
114
115 Insert(100, 102);
116 Cache::Handle* h2 = cache_->Lookup(EncodeKey(100));
117 ASSERT_EQ(102, DecodeValue(cache_->Value(h2)));
118 ASSERT_EQ(0, deleted_keys_.size());
119
120 cache_->Release(h1);
121 ASSERT_EQ(1, deleted_keys_.size());
122 ASSERT_EQ(100, deleted_keys_[0]);
123 ASSERT_EQ(101, deleted_values_[0]);
124
125 Erase(100);
126 ASSERT_EQ(-1, Lookup(100));
127 ASSERT_EQ(1, deleted_keys_.size());
128
129 cache_->Release(h2);
130 ASSERT_EQ(2, deleted_keys_.size());
131 ASSERT_EQ(100, deleted_keys_[1]);
132 ASSERT_EQ(102, deleted_values_[1]);
133 }
134
TEST(CacheTest,EvictionPolicy)135 TEST(CacheTest, EvictionPolicy) {
136 Insert(100, 101);
137 Insert(200, 201);
138
139 // Frequently used entry must be kept around
140 for (int i = 0; i < kCacheSize + 100; i++) {
141 Insert(1000+i, 2000+i);
142 ASSERT_EQ(2000+i, Lookup(1000+i));
143 ASSERT_EQ(101, Lookup(100));
144 }
145 ASSERT_EQ(101, Lookup(100));
146 ASSERT_EQ(-1, Lookup(200));
147 }
148
TEST(CacheTest,HeavyEntries)149 TEST(CacheTest, HeavyEntries) {
150 // Add a bunch of light and heavy entries and then count the combined
151 // size of items still in the cache, which must be approximately the
152 // same as the total capacity.
153 const int kLight = 1;
154 const int kHeavy = 10;
155 int added = 0;
156 int index = 0;
157 while (added < 2*kCacheSize) {
158 const int weight = (index & 1) ? kLight : kHeavy;
159 Insert(index, 1000+index, weight);
160 added += weight;
161 index++;
162 }
163
164 int cached_weight = 0;
165 for (int i = 0; i < index; i++) {
166 const int weight = (i & 1 ? kLight : kHeavy);
167 int r = Lookup(i);
168 if (r >= 0) {
169 cached_weight += weight;
170 ASSERT_EQ(1000+i, r);
171 }
172 }
173 ASSERT_LE(cached_weight, kCacheSize + kCacheSize/10);
174 }
175
TEST(CacheTest,NewId)176 TEST(CacheTest, NewId) {
177 uint64_t a = cache_->NewId();
178 uint64_t b = cache_->NewId();
179 ASSERT_NE(a, b);
180 }
181
182 } // namespace leveldb
183
main(int argc,char ** argv)184 int main(int argc, char** argv) {
185 return leveldb::test::RunAllTests();
186 }
187