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1 /*
2  ** Copyright 2011, The Android Open Source Project
3  **
4  ** Licensed under the Apache License, Version 2.0 (the "License");
5  ** you may not use this file except in compliance with the License.
6  ** You may obtain a copy of the License at
7  **
8  **     http://www.apache.org/licenses/LICENSE-2.0
9  **
10  ** Unless required by applicable law or agreed to in writing, software
11  ** distributed under the License is distributed on an "AS IS" BASIS,
12  ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  ** See the License for the specific language governing permissions and
14  ** limitations under the License.
15  */
16 
17 #include "BlobCache.h"
18 
19 #include <fcntl.h>
20 #include <gtest/gtest.h>
21 #include <stdio.h>
22 
23 #include <memory>
24 
25 namespace android {
26 
27 template <typename T>
28 using sp = std::shared_ptr<T>;
29 
30 class BlobCacheTest : public ::testing::Test {
31 protected:
32     enum {
33         OK = 0,
34         BAD_VALUE = -EINVAL,
35     };
36 
37     enum {
38         MAX_KEY_SIZE = 6,
39         MAX_VALUE_SIZE = 8,
40         MAX_TOTAL_SIZE = 13,
41     };
42 
SetUp()43     virtual void SetUp() { mBC.reset(new BlobCache(MAX_KEY_SIZE, MAX_VALUE_SIZE, MAX_TOTAL_SIZE)); }
44 
TearDown()45     virtual void TearDown() { mBC.reset(); }
46 
47     std::unique_ptr<BlobCache> mBC;
48 };
49 
TEST_F(BlobCacheTest,CacheSingleValueSucceeds)50 TEST_F(BlobCacheTest, CacheSingleValueSucceeds) {
51     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
52     ASSERT_EQ(BlobCache::InsertResult::kInserted, mBC->set("abcd", 4, "efgh", 4));
53     ASSERT_EQ(size_t(4), mBC->get("abcd", 4, buf, 4));
54     ASSERT_EQ('e', buf[0]);
55     ASSERT_EQ('f', buf[1]);
56     ASSERT_EQ('g', buf[2]);
57     ASSERT_EQ('h', buf[3]);
58 }
59 
TEST_F(BlobCacheTest,CacheTwoValuesSucceeds)60 TEST_F(BlobCacheTest, CacheTwoValuesSucceeds) {
61     unsigned char buf[2] = {0xee, 0xee};
62     ASSERT_EQ(BlobCache::InsertResult::kInserted, mBC->set("ab", 2, "cd", 2));
63     ASSERT_EQ(BlobCache::InsertResult::kInserted, mBC->set("ef", 2, "gh", 2));
64     ASSERT_EQ(size_t(2), mBC->get("ab", 2, buf, 2));
65     ASSERT_EQ('c', buf[0]);
66     ASSERT_EQ('d', buf[1]);
67     ASSERT_EQ(size_t(2), mBC->get("ef", 2, buf, 2));
68     ASSERT_EQ('g', buf[0]);
69     ASSERT_EQ('h', buf[1]);
70 }
71 
TEST_F(BlobCacheTest,GetOnlyWritesInsideBounds)72 TEST_F(BlobCacheTest, GetOnlyWritesInsideBounds) {
73     unsigned char buf[6] = {0xee, 0xee, 0xee, 0xee, 0xee, 0xee};
74     ASSERT_EQ(BlobCache::InsertResult::kInserted, mBC->set("abcd", 4, "efgh", 4));
75     ASSERT_EQ(size_t(4), mBC->get("abcd", 4, buf + 1, 4));
76     ASSERT_EQ(0xee, buf[0]);
77     ASSERT_EQ('e', buf[1]);
78     ASSERT_EQ('f', buf[2]);
79     ASSERT_EQ('g', buf[3]);
80     ASSERT_EQ('h', buf[4]);
81     ASSERT_EQ(0xee, buf[5]);
82 }
83 
TEST_F(BlobCacheTest,GetOnlyWritesIfBufferIsLargeEnough)84 TEST_F(BlobCacheTest, GetOnlyWritesIfBufferIsLargeEnough) {
85     unsigned char buf[3] = {0xee, 0xee, 0xee};
86     ASSERT_EQ(BlobCache::InsertResult::kInserted, mBC->set("abcd", 4, "efgh", 4));
87     ASSERT_EQ(size_t(4), mBC->get("abcd", 4, buf, 3));
88     ASSERT_EQ(0xee, buf[0]);
89     ASSERT_EQ(0xee, buf[1]);
90     ASSERT_EQ(0xee, buf[2]);
91 }
92 
TEST_F(BlobCacheTest,GetDoesntAccessNullBuffer)93 TEST_F(BlobCacheTest, GetDoesntAccessNullBuffer) {
94     ASSERT_EQ(BlobCache::InsertResult::kInserted, mBC->set("abcd", 4, "efgh", 4));
95     ASSERT_EQ(size_t(4), mBC->get("abcd", 4, nullptr, 0));
96 }
97 
TEST_F(BlobCacheTest,MultipleSetsCacheLatestValue)98 TEST_F(BlobCacheTest, MultipleSetsCacheLatestValue) {
99     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
100     ASSERT_EQ(BlobCache::InsertResult::kInserted, mBC->set("abcd", 4, "efgh", 4));
101     ASSERT_EQ(BlobCache::InsertResult::kInserted, mBC->set("abcd", 4, "ijkl", 4));
102     ASSERT_EQ(size_t(4), mBC->get("abcd", 4, buf, 4));
103     ASSERT_EQ('i', buf[0]);
104     ASSERT_EQ('j', buf[1]);
105     ASSERT_EQ('k', buf[2]);
106     ASSERT_EQ('l', buf[3]);
107 }
108 
TEST_F(BlobCacheTest,SecondSetKeepsFirstValueIfTooLarge)109 TEST_F(BlobCacheTest, SecondSetKeepsFirstValueIfTooLarge) {
110     unsigned char buf[MAX_VALUE_SIZE + 1] = {0xee, 0xee, 0xee, 0xee};
111     ASSERT_EQ(BlobCache::InsertResult::kInserted, mBC->set("abcd", 4, "efgh", 4));
112     ASSERT_EQ(BlobCache::InsertResult::kValueTooBig, mBC->set("abcd", 4, buf, MAX_VALUE_SIZE + 1));
113     ASSERT_EQ(size_t(4), mBC->get("abcd", 4, buf, 4));
114     ASSERT_EQ('e', buf[0]);
115     ASSERT_EQ('f', buf[1]);
116     ASSERT_EQ('g', buf[2]);
117     ASSERT_EQ('h', buf[3]);
118 }
119 
TEST_F(BlobCacheTest,DoesntCacheIfKeyIsTooBig)120 TEST_F(BlobCacheTest, DoesntCacheIfKeyIsTooBig) {
121     char key[MAX_KEY_SIZE + 1];
122     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
123     for (int i = 0; i < MAX_KEY_SIZE + 1; i++) {
124         key[i] = 'a';
125     }
126     ASSERT_EQ(BlobCache::InsertResult::kKeyTooBig, mBC->set(key, MAX_KEY_SIZE + 1, "bbbb", 4));
127     ASSERT_EQ(size_t(0), mBC->get(key, MAX_KEY_SIZE + 1, buf, 4));
128     ASSERT_EQ(0xee, buf[0]);
129     ASSERT_EQ(0xee, buf[1]);
130     ASSERT_EQ(0xee, buf[2]);
131     ASSERT_EQ(0xee, buf[3]);
132 }
133 
TEST_F(BlobCacheTest,DoesntCacheIfValueIsTooBig)134 TEST_F(BlobCacheTest, DoesntCacheIfValueIsTooBig) {
135     char buf[MAX_VALUE_SIZE + 1];
136     for (int i = 0; i < MAX_VALUE_SIZE + 1; i++) {
137         buf[i] = 'b';
138     }
139     ASSERT_EQ(BlobCache::InsertResult::kValueTooBig, mBC->set("abcd", 4, buf, MAX_VALUE_SIZE + 1));
140     for (int i = 0; i < MAX_VALUE_SIZE + 1; i++) {
141         buf[i] = 0xee;
142     }
143     ASSERT_EQ(size_t(0), mBC->get("abcd", 4, buf, MAX_VALUE_SIZE + 1));
144     for (int i = 0; i < MAX_VALUE_SIZE + 1; i++) {
145         SCOPED_TRACE(i);
146         ASSERT_EQ(0xee, buf[i]);
147     }
148 }
149 
TEST_F(BlobCacheTest,DoesntCacheIfKeyValuePairIsTooBig)150 TEST_F(BlobCacheTest, DoesntCacheIfKeyValuePairIsTooBig) {
151     // Check a testing assumptions
152     ASSERT_TRUE(MAX_TOTAL_SIZE < MAX_KEY_SIZE + MAX_VALUE_SIZE);
153     ASSERT_TRUE(MAX_KEY_SIZE < MAX_TOTAL_SIZE);
154 
155     enum { bufSize = MAX_TOTAL_SIZE - MAX_KEY_SIZE + 1 };
156 
157     char key[MAX_KEY_SIZE];
158     char buf[bufSize];
159     for (int i = 0; i < MAX_KEY_SIZE; i++) {
160         key[i] = 'a';
161     }
162     for (int i = 0; i < bufSize; i++) {
163         buf[i] = 'b';
164     }
165 
166     ASSERT_EQ(BlobCache::InsertResult::kCombinedTooBig,
167               mBC->set(key, MAX_KEY_SIZE, buf, MAX_VALUE_SIZE));
168     ASSERT_EQ(size_t(0), mBC->get(key, MAX_KEY_SIZE, nullptr, 0));
169 }
170 
TEST_F(BlobCacheTest,CacheMaxKeySizeSucceeds)171 TEST_F(BlobCacheTest, CacheMaxKeySizeSucceeds) {
172     char key[MAX_KEY_SIZE];
173     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
174     for (int i = 0; i < MAX_KEY_SIZE; i++) {
175         key[i] = 'a';
176     }
177     ASSERT_EQ(BlobCache::InsertResult::kInserted, mBC->set(key, MAX_KEY_SIZE, "wxyz", 4));
178     ASSERT_EQ(size_t(4), mBC->get(key, MAX_KEY_SIZE, buf, 4));
179     ASSERT_EQ('w', buf[0]);
180     ASSERT_EQ('x', buf[1]);
181     ASSERT_EQ('y', buf[2]);
182     ASSERT_EQ('z', buf[3]);
183 }
184 
TEST_F(BlobCacheTest,CacheMaxValueSizeSucceeds)185 TEST_F(BlobCacheTest, CacheMaxValueSizeSucceeds) {
186     char buf[MAX_VALUE_SIZE];
187     for (int i = 0; i < MAX_VALUE_SIZE; i++) {
188         buf[i] = 'b';
189     }
190     ASSERT_EQ(BlobCache::InsertResult::kInserted, mBC->set("abcd", 4, buf, MAX_VALUE_SIZE));
191     for (int i = 0; i < MAX_VALUE_SIZE; i++) {
192         buf[i] = 0xee;
193     }
194     ASSERT_EQ(size_t(MAX_VALUE_SIZE), mBC->get("abcd", 4, buf, MAX_VALUE_SIZE));
195     for (int i = 0; i < MAX_VALUE_SIZE; i++) {
196         SCOPED_TRACE(i);
197         ASSERT_EQ('b', buf[i]);
198     }
199 }
200 
TEST_F(BlobCacheTest,CacheMaxKeyValuePairSizeSucceeds)201 TEST_F(BlobCacheTest, CacheMaxKeyValuePairSizeSucceeds) {
202     // Check a testing assumption
203     ASSERT_TRUE(MAX_KEY_SIZE < MAX_TOTAL_SIZE);
204 
205     enum { bufSize = MAX_TOTAL_SIZE - MAX_KEY_SIZE };
206 
207     char key[MAX_KEY_SIZE];
208     char buf[bufSize];
209     for (int i = 0; i < MAX_KEY_SIZE; i++) {
210         key[i] = 'a';
211     }
212     for (int i = 0; i < bufSize; i++) {
213         buf[i] = 'b';
214     }
215 
216     ASSERT_EQ(BlobCache::InsertResult::kInserted, mBC->set(key, MAX_KEY_SIZE, buf, bufSize));
217     ASSERT_EQ(size_t(bufSize), mBC->get(key, MAX_KEY_SIZE, nullptr, 0));
218 }
219 
220 // Verify that kNotEnoughSpace is returned from BlobCache::set when expected.
221 // Note: This relies on internal knowledge of how BlobCache works.
TEST_F(BlobCacheTest,NotEnoughSpace)222 TEST_F(BlobCacheTest, NotEnoughSpace) {
223     // Insert a small entry into the cache.
224     ASSERT_EQ(BlobCache::InsertResult::kInserted, mBC->set("x", 1, "y", 1));
225 
226     // Attempt to put a max size entry into the cache. If the cache were empty,
227     // as in CacheMaxKeyValuePairSizeSucceeds, this would succeed. Based on the
228     // current logic of BlobCache, the small entry is not big enough to allow it
229     // to be cleaned to insert the new entry.
230     ASSERT_TRUE(MAX_KEY_SIZE < MAX_TOTAL_SIZE);
231 
232     enum { bufSize = MAX_TOTAL_SIZE - MAX_KEY_SIZE };
233 
234     char key[MAX_KEY_SIZE];
235     char buf[bufSize];
236     for (int i = 0; i < MAX_KEY_SIZE; i++) {
237         key[i] = 'a';
238     }
239     for (int i = 0; i < bufSize; i++) {
240         buf[i] = 'b';
241     }
242 
243     ASSERT_EQ(BlobCache::InsertResult::kNotEnoughSpace, mBC->set(key, MAX_KEY_SIZE, buf, bufSize));
244     ASSERT_EQ(0, mBC->get(key, MAX_KEY_SIZE, nullptr, 0));
245 
246     // The original entry remains in the cache.
247     unsigned char buf2[1] = {0xee};
248     ASSERT_EQ(size_t(1), mBC->get("x", 1, buf2, 1));
249     ASSERT_EQ('y', buf2[0]);
250 }
251 
TEST_F(BlobCacheTest,CacheMinKeyAndValueSizeSucceeds)252 TEST_F(BlobCacheTest, CacheMinKeyAndValueSizeSucceeds) {
253     unsigned char buf[1] = {0xee};
254     ASSERT_EQ(BlobCache::InsertResult::kInserted, mBC->set("x", 1, "y", 1));
255     ASSERT_EQ(size_t(1), mBC->get("x", 1, buf, 1));
256     ASSERT_EQ('y', buf[0]);
257 }
258 
TEST_F(BlobCacheTest,CacheSizeDoesntExceedTotalLimit)259 TEST_F(BlobCacheTest, CacheSizeDoesntExceedTotalLimit) {
260     for (int i = 0; i < 256; i++) {
261         uint8_t k = i;
262         mBC->set(&k, 1, "x", 1);
263     }
264     int numCached = 0;
265     for (int i = 0; i < 256; i++) {
266         uint8_t k = i;
267         if (mBC->get(&k, 1, nullptr, 0) == 1) {
268             numCached++;
269         }
270     }
271     ASSERT_GE(MAX_TOTAL_SIZE / 2, numCached);
272 }
273 
TEST_F(BlobCacheTest,ExceedingTotalLimitHalvesCacheSize)274 TEST_F(BlobCacheTest, ExceedingTotalLimitHalvesCacheSize) {
275     // Fill up the entire cache with 1 char key/value pairs.
276     const int maxEntries = MAX_TOTAL_SIZE / 2;
277     for (int i = 0; i < maxEntries; i++) {
278         uint8_t k = i;
279         ASSERT_EQ(BlobCache::InsertResult::kInserted, mBC->set(&k, 1, "x", 1));
280     }
281     // Insert one more entry, causing a cache overflow.
282     {
283         uint8_t k = maxEntries;
284         ASSERT_EQ(BlobCache::InsertResult::kDidClean, mBC->set(&k, 1, "x", 1));
285     }
286     // Count the number of entries in the cache.
287     int numCached = 0;
288     for (int i = 0; i < maxEntries + 1; i++) {
289         uint8_t k = i;
290         if (mBC->get(&k, 1, nullptr, 0) == 1) {
291             numCached++;
292         }
293     }
294     ASSERT_EQ(maxEntries / 2 + 1, numCached);
295 }
296 
TEST_F(BlobCacheTest,InvalidKeySize)297 TEST_F(BlobCacheTest, InvalidKeySize) {
298     ASSERT_EQ(BlobCache::InsertResult::kInvalidKeySize, mBC->set("", 0, "efgh", 4));
299 }
300 
TEST_F(BlobCacheTest,InvalidValueSize)301 TEST_F(BlobCacheTest, InvalidValueSize) {
302     ASSERT_EQ(BlobCache::InsertResult::kInvalidValueSize, mBC->set("abcd", 4, "", 0));
303 }
304 
305 class BlobCacheFlattenTest : public BlobCacheTest {
306 protected:
SetUp()307     virtual void SetUp() {
308         BlobCacheTest::SetUp();
309         mBC2.reset(new BlobCache(MAX_KEY_SIZE, MAX_VALUE_SIZE, MAX_TOTAL_SIZE));
310     }
311 
TearDown()312     virtual void TearDown() {
313         mBC2.reset();
314         BlobCacheTest::TearDown();
315     }
316 
roundTrip()317     void roundTrip() {
318         size_t size = mBC->getFlattenedSize();
319         uint8_t* flat = new uint8_t[size];
320         ASSERT_EQ(OK, mBC->flatten(flat, size));
321         ASSERT_EQ(OK, mBC2->unflatten(flat, size));
322         delete[] flat;
323     }
324 
325     sp<BlobCache> mBC2;
326 };
327 
TEST_F(BlobCacheFlattenTest,FlattenOneValue)328 TEST_F(BlobCacheFlattenTest, FlattenOneValue) {
329     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
330     mBC->set("abcd", 4, "efgh", 4);
331     roundTrip();
332     ASSERT_EQ(size_t(4), mBC2->get("abcd", 4, buf, 4));
333     ASSERT_EQ('e', buf[0]);
334     ASSERT_EQ('f', buf[1]);
335     ASSERT_EQ('g', buf[2]);
336     ASSERT_EQ('h', buf[3]);
337 }
338 
TEST_F(BlobCacheFlattenTest,FlattenFullCache)339 TEST_F(BlobCacheFlattenTest, FlattenFullCache) {
340     // Fill up the entire cache with 1 char key/value pairs.
341     const int maxEntries = MAX_TOTAL_SIZE / 2;
342     for (int i = 0; i < maxEntries; i++) {
343         uint8_t k = i;
344         mBC->set(&k, 1, &k, 1);
345     }
346 
347     roundTrip();
348 
349     // Verify the deserialized cache
350     for (int i = 0; i < maxEntries; i++) {
351         uint8_t k = i;
352         uint8_t v = 0xee;
353         ASSERT_EQ(size_t(1), mBC2->get(&k, 1, &v, 1));
354         ASSERT_EQ(k, v);
355     }
356 }
357 
TEST_F(BlobCacheFlattenTest,FlattenDoesntChangeCache)358 TEST_F(BlobCacheFlattenTest, FlattenDoesntChangeCache) {
359     // Fill up the entire cache with 1 char key/value pairs.
360     const int maxEntries = MAX_TOTAL_SIZE / 2;
361     for (int i = 0; i < maxEntries; i++) {
362         uint8_t k = i;
363         mBC->set(&k, 1, &k, 1);
364     }
365 
366     size_t size = mBC->getFlattenedSize();
367     uint8_t* flat = new uint8_t[size];
368     ASSERT_EQ(OK, mBC->flatten(flat, size));
369     delete[] flat;
370 
371     // Verify the cache that we just serialized
372     for (int i = 0; i < maxEntries; i++) {
373         uint8_t k = i;
374         uint8_t v = 0xee;
375         ASSERT_EQ(size_t(1), mBC->get(&k, 1, &v, 1));
376         ASSERT_EQ(k, v);
377     }
378 }
379 
TEST_F(BlobCacheFlattenTest,FlattenCatchesBufferTooSmall)380 TEST_F(BlobCacheFlattenTest, FlattenCatchesBufferTooSmall) {
381     // Fill up the entire cache with 1 char key/value pairs.
382     const int maxEntries = MAX_TOTAL_SIZE / 2;
383     for (int i = 0; i < maxEntries; i++) {
384         uint8_t k = i;
385         mBC->set(&k, 1, &k, 1);
386     }
387 
388     size_t size = mBC->getFlattenedSize() - 1;
389     uint8_t* flat = new uint8_t[size];
390     // ASSERT_EQ(BAD_VALUE, mBC->flatten(flat, size));
391     // TODO: The above fails. I expect this is so because getFlattenedSize()
392     // overstimates the size by using PROPERTY_VALUE_MAX.
393     delete[] flat;
394 }
395 
TEST_F(BlobCacheFlattenTest,UnflattenCatchesBadMagic)396 TEST_F(BlobCacheFlattenTest, UnflattenCatchesBadMagic) {
397     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
398     mBC->set("abcd", 4, "efgh", 4);
399 
400     size_t size = mBC->getFlattenedSize();
401     uint8_t* flat = new uint8_t[size];
402     ASSERT_EQ(OK, mBC->flatten(flat, size));
403     flat[1] = ~flat[1];
404 
405     // Bad magic should cause an error.
406     ASSERT_EQ(BAD_VALUE, mBC2->unflatten(flat, size));
407     delete[] flat;
408 
409     // The error should cause the unflatten to result in an empty cache
410     ASSERT_EQ(size_t(0), mBC2->get("abcd", 4, buf, 4));
411 }
412 
TEST_F(BlobCacheFlattenTest,UnflattenCatchesBadBlobCacheVersion)413 TEST_F(BlobCacheFlattenTest, UnflattenCatchesBadBlobCacheVersion) {
414     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
415     mBC->set("abcd", 4, "efgh", 4);
416 
417     size_t size = mBC->getFlattenedSize();
418     uint8_t* flat = new uint8_t[size];
419     ASSERT_EQ(OK, mBC->flatten(flat, size));
420     flat[5] = ~flat[5];
421 
422     // Version mismatches shouldn't cause errors, but should not use the
423     // serialized entries
424     ASSERT_EQ(OK, mBC2->unflatten(flat, size));
425     delete[] flat;
426 
427     // The version mismatch should cause the unflatten to result in an empty
428     // cache
429     ASSERT_EQ(size_t(0), mBC2->get("abcd", 4, buf, 4));
430 }
431 
TEST_F(BlobCacheFlattenTest,UnflattenCatchesBadBlobCacheDeviceVersion)432 TEST_F(BlobCacheFlattenTest, UnflattenCatchesBadBlobCacheDeviceVersion) {
433     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
434     mBC->set("abcd", 4, "efgh", 4);
435 
436     size_t size = mBC->getFlattenedSize();
437     uint8_t* flat = new uint8_t[size];
438     ASSERT_EQ(OK, mBC->flatten(flat, size));
439     flat[10] = ~flat[10];
440 
441     // Version mismatches shouldn't cause errors, but should not use the
442     // serialized entries
443     ASSERT_EQ(OK, mBC2->unflatten(flat, size));
444     delete[] flat;
445 
446     // The version mismatch should cause the unflatten to result in an empty
447     // cache
448     ASSERT_EQ(size_t(0), mBC2->get("abcd", 4, buf, 4));
449 }
450 
TEST_F(BlobCacheFlattenTest,UnflattenCatchesBufferTooSmall)451 TEST_F(BlobCacheFlattenTest, UnflattenCatchesBufferTooSmall) {
452     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
453     mBC->set("abcd", 4, "efgh", 4);
454 
455     size_t size = mBC->getFlattenedSize();
456     uint8_t* flat = new uint8_t[size];
457     ASSERT_EQ(OK, mBC->flatten(flat, size));
458 
459     // A buffer truncation shouldt cause an error
460     // ASSERT_EQ(BAD_VALUE, mBC2->unflatten(flat, size-1));
461     // TODO: The above appears to fail because getFlattenedSize() is
462     // conservative.
463     delete[] flat;
464 
465     // The error should cause the unflatten to result in an empty cache
466     ASSERT_EQ(size_t(0), mBC2->get("abcd", 4, buf, 4));
467 }
468 
469 // Test for a divide by zero bug (b/239862516). Before the fix, unflatten() would not reset
470 // mTotalSize when it encountered an error, which would trigger division by 0 in clean() in the
471 // right conditions.
TEST_F(BlobCacheFlattenTest,SetAfterFailedUnflatten)472 TEST_F(BlobCacheFlattenTest, SetAfterFailedUnflatten) {
473     // isCleanable() must be true, so mTotalSize must be > mMaxTotalSize / 2 after unflattening
474     // after one entry is lost. To make this the case, MaxTotalSize is 30 and three 10 sized
475     // entries are used. One of those entries is lost, resulting in mTotalSize=20
476     const size_t kMaxKeySize = 10;
477     const size_t kMaxValueSize = 10;
478     const size_t kMaxTotalSize = 30;
479     mBC.reset(new BlobCache(kMaxKeySize, kMaxValueSize, kMaxTotalSize));
480     mBC2.reset(new BlobCache(kMaxKeySize, kMaxValueSize, kMaxTotalSize));
481     mBC->set("aaaaa", 5, "aaaaa", 5);
482     mBC->set("bbbbb", 5, "bbbbb", 5);
483     mBC->set("ccccc", 5, "ccccc", 5);
484 
485     size_t size = mBC->getFlattenedSize();
486     uint8_t* flat = new uint8_t[size];
487     ASSERT_EQ(OK, mBC->flatten(flat, size));
488 
489     ASSERT_EQ(BAD_VALUE, mBC2->unflatten(flat, size - 10));
490     delete[] flat;
491 
492     // This line will trigger clean() which caused a crash.
493     mBC2->set("dddddddddd", 10, "dddddddddd", 10);
494 }
495 
496 } // namespace android
497