nn/driver/cache/BlobCache/BlobCache_test.cpp - platform/frameworks/ml - Git at Google

 /*
  ** Copyright 2011, The Android Open Source Project
  **
  ** Licensed under the Apache License, Version 2.0 (the "License");
  ** you may not use this file except in compliance with the License.
  ** You may obtain a copy of the License at
  **
  **     http://www.apache.org/licenses/LICENSE-2.0
  **
  ** Unless required by applicable law or agreed to in writing, software
  ** distributed under the License is distributed on an "AS IS" BASIS,
  ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  ** See the License for the specific language governing permissions and
  ** limitations under the License.
  */

 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>

 #include <algorithm>
 #include <memory>
 #include <numeric>
 #include <random>

 #include <gtest/gtest.h>

 #include "BlobCache.h"

 namespace android {

 template <typename T>
 using sp = std::shared_ptr<T>;

 class BlobCacheTest : public ::testing::TestWithParam<BlobCache::Policy> {
    protected:
     enum { OK = 0, BAD_VALUE = -EINVAL };

     enum {
         MAX_KEY_SIZE = 6,
         MAX_VALUE_SIZE = 8,
         MAX_TOTAL_SIZE = 13,
     };

     virtual void SetUp() {
         mBC.reset(new BlobCache(MAX_KEY_SIZE, MAX_VALUE_SIZE, MAX_TOTAL_SIZE, GetParam()));
     }

     virtual void TearDown() { mBC.reset(); }

     std::unique_ptr<BlobCache> mBC;
 };

 INSTANTIATE_TEST_SUITE_P(
         Policy, BlobCacheTest,
         ::testing::Values(
                 BlobCache::Policy(BlobCache::Select::RANDOM, BlobCache::Capacity::HALVE),
                 BlobCache::Policy(BlobCache::Select::LRU, BlobCache::Capacity::HALVE),

                 BlobCache::Policy(BlobCache::Select::RANDOM, BlobCache::Capacity::FIT),
                 BlobCache::Policy(BlobCache::Select::LRU, BlobCache::Capacity::FIT),

                 BlobCache::Policy(BlobCache::Select::RANDOM, BlobCache::Capacity::FIT_HALVE),
                 BlobCache::Policy(BlobCache::Select::LRU, BlobCache::Capacity::FIT_HALVE)));

 TEST_P(BlobCacheTest, CacheSingleValueSucceeds) {
     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
     mBC->set("abcd", 4, "efgh", 4);
     ASSERT_EQ(size_t(4), mBC->get("abcd", 4, buf, 4));
     ASSERT_EQ('e', buf[0]);
     ASSERT_EQ('f', buf[1]);
     ASSERT_EQ('g', buf[2]);
     ASSERT_EQ('h', buf[3]);
 }

 TEST_P(BlobCacheTest, CacheTwoValuesSucceeds) {
     unsigned char buf[2] = {0xee, 0xee};
     mBC->set("ab", 2, "cd", 2);
     mBC->set("ef", 2, "gh", 2);
     ASSERT_EQ(size_t(2), mBC->get("ab", 2, buf, 2));
     ASSERT_EQ('c', buf[0]);
     ASSERT_EQ('d', buf[1]);
     ASSERT_EQ(size_t(2), mBC->get("ef", 2, buf, 2));
     ASSERT_EQ('g', buf[0]);
     ASSERT_EQ('h', buf[1]);
 }

 TEST_P(BlobCacheTest, CacheTwoValuesMallocSucceeds) {
     unsigned char* bufPtr;
     mBC->set("ab", 2, "cd", 2);
     mBC->set("ef", 2, "gh", 2);

     bufPtr = nullptr;
     ASSERT_EQ(size_t(2), mBC->get("ab", 2, &bufPtr, malloc));
     ASSERT_NE(nullptr, bufPtr);
     ASSERT_EQ('c', bufPtr[0]);
     ASSERT_EQ('d', bufPtr[1]);
     free(bufPtr);

     bufPtr = nullptr;
     ASSERT_EQ(size_t(2), mBC->get("ef", 2, &bufPtr, malloc));
     ASSERT_NE(nullptr, bufPtr);
     ASSERT_EQ('g', bufPtr[0]);
     ASSERT_EQ('h', bufPtr[1]);
     free(bufPtr);
 }

 TEST_P(BlobCacheTest, GetOnlyWritesInsideBounds) {
     unsigned char buf[6] = {0xee, 0xee, 0xee, 0xee, 0xee, 0xee};
     mBC->set("abcd", 4, "efgh", 4);
     ASSERT_EQ(size_t(4), mBC->get("abcd", 4, buf + 1, 4));
     ASSERT_EQ(0xee, buf[0]);
     ASSERT_EQ('e', buf[1]);
     ASSERT_EQ('f', buf[2]);
     ASSERT_EQ('g', buf[3]);
     ASSERT_EQ('h', buf[4]);
     ASSERT_EQ(0xee, buf[5]);
 }

 TEST_P(BlobCacheTest, GetOnlyWritesIfBufferIsLargeEnough) {
     unsigned char buf[3] = {0xee, 0xee, 0xee};
     mBC->set("abcd", 4, "efgh", 4);
     ASSERT_EQ(size_t(4), mBC->get("abcd", 4, buf, 3));
     ASSERT_EQ(0xee, buf[0]);
     ASSERT_EQ(0xee, buf[1]);
     ASSERT_EQ(0xee, buf[2]);
 }

 TEST_P(BlobCacheTest, GetWithFailedAllocator) {
     unsigned char buf[3] = {0xee, 0xee, 0xee};
     mBC->set("abcd", 4, "efgh", 4);

     // If allocator fails, verify that we set the value pointer to
     // nullptr, and that we do not modify the buffer that the value
     // pointer originally pointed to.
     unsigned char* bufPtr = &buf[0];
     ASSERT_EQ(size_t(4), mBC->get("abcd", 4, &bufPtr, [](size_t) -> void* { return nullptr; }));
     ASSERT_EQ(nullptr, bufPtr);
     ASSERT_EQ(0xee, buf[0]);
     ASSERT_EQ(0xee, buf[1]);
     ASSERT_EQ(0xee, buf[2]);
 }

 TEST_P(BlobCacheTest, GetDoesntAccessNullBuffer) {
     mBC->set("abcd", 4, "efgh", 4);
     ASSERT_EQ(size_t(4), mBC->get("abcd", 4, NULL, 0));
 }

 TEST_P(BlobCacheTest, MultipleSetsCacheLatestValue) {
     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
     mBC->set("abcd", 4, "efgh", 4);
     mBC->set("abcd", 4, "ijkl", 4);
     ASSERT_EQ(size_t(4), mBC->get("abcd", 4, buf, 4));
     ASSERT_EQ('i', buf[0]);
     ASSERT_EQ('j', buf[1]);
     ASSERT_EQ('k', buf[2]);
     ASSERT_EQ('l', buf[3]);
 }

 TEST_P(BlobCacheTest, SecondSetKeepsFirstValueIfTooLarge) {
     unsigned char buf[MAX_VALUE_SIZE + 1] = {0xee, 0xee, 0xee, 0xee};
     mBC->set("abcd", 4, "efgh", 4);
     mBC->set("abcd", 4, buf, MAX_VALUE_SIZE + 1);
     ASSERT_EQ(size_t(4), mBC->get("abcd", 4, buf, 4));
     ASSERT_EQ('e', buf[0]);
     ASSERT_EQ('f', buf[1]);
     ASSERT_EQ('g', buf[2]);
     ASSERT_EQ('h', buf[3]);
 }

 TEST_P(BlobCacheTest, DoesntCacheIfKeyIsTooBig) {
     char key[MAX_KEY_SIZE + 1];
     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
     for (int i = 0; i < MAX_KEY_SIZE + 1; i++) {
         key[i] = 'a';
     }
     mBC->set(key, MAX_KEY_SIZE + 1, "bbbb", 4);

     ASSERT_EQ(size_t(0), mBC->get(key, MAX_KEY_SIZE + 1, buf, 4));
     ASSERT_EQ(0xee, buf[0]);
     ASSERT_EQ(0xee, buf[1]);
     ASSERT_EQ(0xee, buf[2]);
     ASSERT_EQ(0xee, buf[3]);

     // If key is too large, verify that we do not call the allocator,
     // that we set the value pointer to nullptr, and that we do not
     // modify the buffer that the value pointer originally pointed to.
     unsigned char* bufPtr = &buf[0];
     bool calledAlloc = false;
     ASSERT_EQ(size_t(0), mBC->get(key, MAX_KEY_SIZE + 1, &bufPtr, [&calledAlloc](size_t) -> void* {
         calledAlloc = true;
         return nullptr;
     }));
     ASSERT_EQ(false, calledAlloc);
     ASSERT_EQ(nullptr, bufPtr);
     ASSERT_EQ(0xee, buf[0]);
     ASSERT_EQ(0xee, buf[1]);
     ASSERT_EQ(0xee, buf[2]);
     ASSERT_EQ(0xee, buf[3]);
 }

 TEST_P(BlobCacheTest, DoesntCacheIfValueIsTooBig) {
     unsigned char buf[MAX_VALUE_SIZE + 1];
     for (int i = 0; i < MAX_VALUE_SIZE + 1; i++) {
         buf[i] = 'b';
     }
     mBC->set("abcd", 4, buf, MAX_VALUE_SIZE + 1);
     for (int i = 0; i < MAX_VALUE_SIZE + 1; i++) {
         buf[i] = 0xee;
     }
     ASSERT_EQ(size_t(0), mBC->get("abcd", 4, buf, MAX_VALUE_SIZE + 1));
     for (int i = 0; i < MAX_VALUE_SIZE + 1; i++) {
         SCOPED_TRACE(i);
         ASSERT_EQ(0xee, buf[i]);
     }
 }

 TEST_P(BlobCacheTest, DoesntCacheIfKeyValuePairIsTooBig) {
     // Check a testing assumptions
     ASSERT_TRUE(MAX_TOTAL_SIZE < MAX_KEY_SIZE + MAX_VALUE_SIZE);
     ASSERT_TRUE(MAX_KEY_SIZE < MAX_TOTAL_SIZE);

     enum { bufSize = MAX_TOTAL_SIZE - MAX_KEY_SIZE + 1 };

     char key[MAX_KEY_SIZE];
     char buf[bufSize];
     for (int i = 0; i < MAX_KEY_SIZE; i++) {
         key[i] = 'a';
     }
     for (int i = 0; i < bufSize; i++) {
         buf[i] = 'b';
     }

     mBC->set(key, MAX_KEY_SIZE, buf, MAX_VALUE_SIZE);
     ASSERT_EQ(size_t(0), mBC->get(key, MAX_KEY_SIZE, NULL, 0));
 }

 TEST_P(BlobCacheTest, CacheMaxKeySizeSucceeds) {
     char key[MAX_KEY_SIZE];
     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
     for (int i = 0; i < MAX_KEY_SIZE; i++) {
         key[i] = 'a';
     }
     mBC->set(key, MAX_KEY_SIZE, "wxyz", 4);
     ASSERT_EQ(size_t(4), mBC->get(key, MAX_KEY_SIZE, buf, 4));
     ASSERT_EQ('w', buf[0]);
     ASSERT_EQ('x', buf[1]);
     ASSERT_EQ('y', buf[2]);
     ASSERT_EQ('z', buf[3]);
 }

 TEST_P(BlobCacheTest, CacheMaxValueSizeSucceeds) {
     char buf[MAX_VALUE_SIZE];
     for (int i = 0; i < MAX_VALUE_SIZE; i++) {
         buf[i] = 'b';
     }
     mBC->set("abcd", 4, buf, MAX_VALUE_SIZE);
     for (int i = 0; i < MAX_VALUE_SIZE; i++) {
         buf[i] = 0xee;
     }
     ASSERT_EQ(size_t(MAX_VALUE_SIZE), mBC->get("abcd", 4, buf, MAX_VALUE_SIZE));
     for (int i = 0; i < MAX_VALUE_SIZE; i++) {
         SCOPED_TRACE(i);
         ASSERT_EQ('b', buf[i]);
     }
 }

 TEST_P(BlobCacheTest, CacheMaxKeyValuePairSizeSucceeds) {
     // Check a testing assumption
     ASSERT_TRUE(MAX_KEY_SIZE < MAX_TOTAL_SIZE);

     enum { bufSize = MAX_TOTAL_SIZE - MAX_KEY_SIZE };

     char key[MAX_KEY_SIZE];
     char buf[bufSize];
     for (int i = 0; i < MAX_KEY_SIZE; i++) {
         key[i] = 'a';
     }
     for (int i = 0; i < bufSize; i++) {
         buf[i] = 'b';
     }

     mBC->set(key, MAX_KEY_SIZE, buf, bufSize);
     ASSERT_EQ(size_t(bufSize), mBC->get(key, MAX_KEY_SIZE, NULL, 0));
 }

 TEST_P(BlobCacheTest, CacheMinKeyAndValueSizeSucceeds) {
     unsigned char buf[1] = {0xee};
     mBC->set("x", 1, "y", 1);
     ASSERT_EQ(size_t(1), mBC->get("x", 1, buf, 1));
     ASSERT_EQ('y', buf[0]);
 }

 TEST_P(BlobCacheTest, CacheSizeDoesntExceedTotalLimit) {
     for (int i = 0; i < 256; i++) {
         uint8_t k = i;
         mBC->set(&k, 1, "x", 1);
     }
     int numCached = 0;
     for (int i = 0; i < 256; i++) {
         uint8_t k = i;
         if (mBC->get(&k, 1, NULL, 0) == 1) {
             numCached++;
         }
     }
     ASSERT_GE(MAX_TOTAL_SIZE / 2, numCached);
 }

 TEST_P(BlobCacheTest, ExceedingTotalLimitHalvesCacheSize) {
     if (GetParam().second == BlobCache::Capacity::FIT)
         return;  // test doesn't apply for this policy

     // Fill up the entire cache with 1 char key/value pairs.
     const int maxEntries = MAX_TOTAL_SIZE / 2;
     for (int i = 0; i < maxEntries; i++) {
         uint8_t k = i;
         mBC->set(&k, 1, "x", 1);
     }
     // Insert one more entry, causing a cache overflow.
     {
         uint8_t k = maxEntries;
         mBC->set(&k, 1, "x", 1);
     }
     // Count the number of entries in the cache; and check which
     // entries they are.
     int numCached = 0;
     for (int i = 0; i < maxEntries + 1; i++) {
         uint8_t k = i;
         bool found = (mBC->get(&k, 1, NULL, 0) == 1);
         if (found) numCached++;
         if (GetParam().first == BlobCache::Select::LRU) {
             SCOPED_TRACE(i);
             ASSERT_EQ(found, i >= maxEntries / 2);
         }
     }
     ASSERT_EQ(maxEntries / 2 + 1, numCached);
 }

 TEST_P(BlobCacheTest, ExceedingTotalLimitJustFitsSmallEntry) {
     if (GetParam().second != BlobCache::Capacity::FIT)
         return;  // test doesn't apply for this policy

     // Fill up the entire cache with 1 char key/value pairs.
     const int maxEntries = MAX_TOTAL_SIZE / 2;
     for (int i = 0; i < maxEntries; i++) {
         uint8_t k = i;
         mBC->set(&k, 1, "x", 1);
     }
     // Insert one more entry, causing a cache overflow.
     {
         uint8_t k = maxEntries;
         mBC->set(&k, 1, "x", 1);
     }
     // Count the number of entries in the cache.
     int numCached = 0;
     for (int i = 0; i < maxEntries + 1; i++) {
         uint8_t k = i;
         if (mBC->get(&k, 1, NULL, 0) == 1) numCached++;
     }
     ASSERT_EQ(maxEntries, numCached);
 }

 // Also see corresponding test in nnCache_test.cpp
 TEST_P(BlobCacheTest, ExceedingTotalLimitFitsBigEntry) {
     // Fill up the entire cache with 1 char key/value pairs.
     const int maxEntries = MAX_TOTAL_SIZE / 2;
     for (int i = 0; i < maxEntries; i++) {
         uint8_t k = i;
         mBC->set(&k, 1, "x", 1);
     }
     // Insert one more entry, causing a cache overflow.
     const int bigValueSize = std::min((MAX_TOTAL_SIZE * 3) / 4 - 1, int(MAX_VALUE_SIZE));
     ASSERT_GT(bigValueSize + 1, MAX_TOTAL_SIZE / 2);  // Check testing assumption
     {
         unsigned char buf[MAX_VALUE_SIZE];
         for (int i = 0; i < bigValueSize; i++) buf[i] = 0xee;
         uint8_t k = maxEntries;
         mBC->set(&k, 1, buf, bigValueSize);
     }
     // Count the number and size of entries in the cache.
     int numCached = 0;
     size_t sizeCached = 0;
     for (int i = 0; i < maxEntries + 1; i++) {
         uint8_t k = i;
         size_t size = mBC->get(&k, 1, NULL, 0);
         if (size) {
             numCached++;
             sizeCached += (size + 1);
         }
     }
     switch (GetParam().second) {
         case BlobCache::Capacity::HALVE:
             // New value is too big for this cleaning algorithm.  So
             // we cleaned the cache, but did not insert the new value.
             ASSERT_EQ(maxEntries / 2, numCached);
             ASSERT_EQ(size_t((maxEntries / 2) * 2), sizeCached);
             break;
         case BlobCache::Capacity::FIT:
         case BlobCache::Capacity::FIT_HALVE: {
             // We had to clean more than half the cache to fit the new
             // value.
             const int initialNumEntries = maxEntries;
             const int initialSizeCached = initialNumEntries * 2;
             const int initialFreeSpace = MAX_TOTAL_SIZE - initialSizeCached;

             // (bigValueSize + 1) = value size + key size
             // trailing "+ 1" is in order to round up
             // "/ 2" is because initial entries are size 2 (1 byte key, 1 byte value)
             const int cleanNumEntries = ((bigValueSize + 1) - initialFreeSpace + 1) / 2;

             const int cleanSpace = cleanNumEntries * 2;
             const int postCleanNumEntries = initialNumEntries - cleanNumEntries;
             const int postCleanSizeCached = initialSizeCached - cleanSpace;
             ASSERT_EQ(postCleanNumEntries + 1, numCached);
             ASSERT_EQ(size_t(postCleanSizeCached + bigValueSize + 1), sizeCached);

             break;
         }
         default:
             FAIL() << "Unknown Capacity value";
     }
 }

 TEST_P(BlobCacheTest, FailedGetWithAllocator) {
     // If get doesn't find anything, verify that we do not call the
     // allocator, that we set the value pointer to nullptr, and that
     // we do not modify the buffer that the value pointer originally
     // pointed to.
     unsigned char buf[1] = {0xee};
     unsigned char* bufPtr = &buf[0];
     bool calledAlloc = false;
     ASSERT_EQ(size_t(0), mBC->get("a", 1, &bufPtr, [&calledAlloc](size_t) -> void* {
         calledAlloc = true;
         return nullptr;
     }));
     ASSERT_EQ(false, calledAlloc);
     ASSERT_EQ(nullptr, bufPtr);
     ASSERT_EQ(0xee, buf[0]);
 }

 TEST_P(BlobCacheTest, ExceedingTotalLimitRemovesLRUEntries) {
     if (GetParam().first != BlobCache::Select::LRU) return;  // test doesn't apply for this policy

     // Fill up the entire cache with 1 char key/value pairs.
     static const int maxEntries = MAX_TOTAL_SIZE / 2;
     for (int i = 0; i < maxEntries; i++) {
         uint8_t k = i;
         mBC->set(&k, 1, "x", 1);
     }

     // Access entries in some known pseudorandom order.
     int accessSequence[maxEntries];
     std::iota(&accessSequence[0], &accessSequence[maxEntries], 0);
     std::mt19937 randomEngine(MAX_TOTAL_SIZE /* seed */);
     std::shuffle(&accessSequence[0], &accessSequence[maxEntries], randomEngine);
     for (int i = 0; i < maxEntries; i++) {
         uint8_t k = accessSequence[i];
         uint8_t buf[1];
         // If we were to pass NULL to get() as the value pointer, this
         // won't count as an access for LRU purposes.
         mBC->get(&k, 1, buf, 1);
     }

     // Insert one more entry, causing a cache overflow.
     {
         uint8_t k = maxEntries;
         mBC->set(&k, 1, "x", 1);
     }

     // Check which entries are in the cache.  We expect to see the
     // "one more entry" we just added, and also the most-recently
     // accessed (according to accessSequence).  That is, we should
     // find exactly the entries with the following keys:
     // . maxEntries
     // . accessSequence[j..maxEntries-1] for some 0 <= j < maxEntries
     uint8_t k = maxEntries;
     ASSERT_EQ(size_t(1), mBC->get(&k, 1, NULL, 0));
     bool foundAny = false;
     for (int i = 0; i < maxEntries; i++) {
         uint8_t k = accessSequence[i];
         bool found = (mBC->get(&k, 1, NULL, 0) == 1);
         if (foundAny == found) continue;
         if (!foundAny) {
             // found == true, so we just discovered j == i
             foundAny = true;
         } else {
             // foundAny == true, found == false -- oops
             FAIL() << "found [" << i - 1 << "]th entry but not [" << i << "]th entry";
         }
     }
 }

 class BlobCacheFlattenTest : public BlobCacheTest {
    protected:
     virtual void SetUp() {
         BlobCacheTest::SetUp();
         mBC2.reset(new BlobCache(MAX_KEY_SIZE, MAX_VALUE_SIZE, MAX_TOTAL_SIZE, GetParam()));
     }

     virtual void TearDown() {
         mBC2.reset();
         BlobCacheTest::TearDown();
     }

     void roundTrip() {
         size_t size = mBC->getFlattenedSize();
         uint8_t* flat = new uint8_t[size];
         ASSERT_EQ(OK, mBC->flatten(flat, size));
         ASSERT_EQ(OK, mBC2->unflatten(flat, size));
         delete[] flat;
     }

     sp<BlobCache> mBC2;
 };

 INSTANTIATE_TEST_SUITE_P(
         Policy, BlobCacheFlattenTest,
         ::testing::Values(
                 BlobCache::Policy(BlobCache::Select::RANDOM, BlobCache::Capacity::HALVE),
                 BlobCache::Policy(BlobCache::Select::LRU, BlobCache::Capacity::HALVE),

                 BlobCache::Policy(BlobCache::Select::RANDOM, BlobCache::Capacity::FIT),
                 BlobCache::Policy(BlobCache::Select::LRU, BlobCache::Capacity::FIT),

                 BlobCache::Policy(BlobCache::Select::RANDOM, BlobCache::Capacity::FIT_HALVE),
                 BlobCache::Policy(BlobCache::Select::LRU, BlobCache::Capacity::FIT_HALVE)));

 TEST_P(BlobCacheFlattenTest, FlattenOneValue) {
     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
     mBC->set("abcd", 4, "efgh", 4);
     roundTrip();
     ASSERT_EQ(size_t(4), mBC2->get("abcd", 4, buf, 4));
     ASSERT_EQ('e', buf[0]);
     ASSERT_EQ('f', buf[1]);
     ASSERT_EQ('g', buf[2]);
     ASSERT_EQ('h', buf[3]);
 }

 TEST_P(BlobCacheFlattenTest, FlattenFullCache) {
     // Fill up the entire cache with 1 char key/value pairs.
     const int maxEntries = MAX_TOTAL_SIZE / 2;
     for (int i = 0; i < maxEntries; i++) {
         uint8_t k = i;
         mBC->set(&k, 1, &k, 1);
     }

     roundTrip();

     // Verify the deserialized cache
     for (int i = 0; i < maxEntries; i++) {
         uint8_t k = i;
         uint8_t v = 0xee;
         ASSERT_EQ(size_t(1), mBC2->get(&k, 1, &v, 1));
         ASSERT_EQ(k, v);
     }
 }

 TEST_P(BlobCacheFlattenTest, FlattenDoesntChangeCache) {
     // Fill up the entire cache with 1 char key/value pairs.
     const int maxEntries = MAX_TOTAL_SIZE / 2;
     for (int i = 0; i < maxEntries; i++) {
         uint8_t k = i;
         mBC->set(&k, 1, &k, 1);
     }

     size_t size = mBC->getFlattenedSize();
     uint8_t* flat = new uint8_t[size];
     ASSERT_EQ(OK, mBC->flatten(flat, size));
     delete[] flat;

     // Verify the cache that we just serialized
     for (int i = 0; i < maxEntries; i++) {
         uint8_t k = i;
         uint8_t v = 0xee;
         ASSERT_EQ(size_t(1), mBC->get(&k, 1, &v, 1));
         ASSERT_EQ(k, v);
     }
 }

 TEST_P(BlobCacheFlattenTest, FlattenCatchesBufferTooSmall) {
     // Fill up the entire cache with 1 char key/value pairs.
     const int maxEntries = MAX_TOTAL_SIZE / 2;
     for (int i = 0; i < maxEntries; i++) {
         uint8_t k = i;
         mBC->set(&k, 1, &k, 1);
     }

     size_t size = mBC->getFlattenedSize() - 1;
     uint8_t* flat = new uint8_t[size];
     // ASSERT_EQ(BAD_VALUE, mBC->flatten(flat, size));
     // TODO: The above fails. I expect this is so because getFlattenedSize()
     // overstimates the size by using PROPERTY_VALUE_MAX.
     delete[] flat;
 }

 TEST_P(BlobCacheFlattenTest, UnflattenCatchesBadMagic) {
     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
     mBC->set("abcd", 4, "efgh", 4);

     size_t size = mBC->getFlattenedSize();
     uint8_t* flat = new uint8_t[size];
     ASSERT_EQ(OK, mBC->flatten(flat, size));
     flat[1] = ~flat[1];

     // Bad magic should cause an error.
     ASSERT_EQ(BAD_VALUE, mBC2->unflatten(flat, size));
     delete[] flat;

     // The error should cause the unflatten to result in an empty cache
     ASSERT_EQ(size_t(0), mBC2->get("abcd", 4, buf, 4));
 }

 TEST_P(BlobCacheFlattenTest, UnflattenCatchesBadBlobCacheVersion) {
     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
     mBC->set("abcd", 4, "efgh", 4);

     size_t size = mBC->getFlattenedSize();
     uint8_t* flat = new uint8_t[size];
     ASSERT_EQ(OK, mBC->flatten(flat, size));
     flat[5] = ~flat[5];

     // Version mismatches shouldn't cause errors, but should not use the
     // serialized entries
     ASSERT_EQ(OK, mBC2->unflatten(flat, size));
     delete[] flat;

     // The version mismatch should cause the unflatten to result in an empty
     // cache
     ASSERT_EQ(size_t(0), mBC2->get("abcd", 4, buf, 4));
 }

 TEST_P(BlobCacheFlattenTest, UnflattenCatchesBadBlobCacheDeviceVersion) {
     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
     mBC->set("abcd", 4, "efgh", 4);

     size_t size = mBC->getFlattenedSize();
     uint8_t* flat = new uint8_t[size];
     ASSERT_EQ(OK, mBC->flatten(flat, size));
     flat[10] = ~flat[10];

     // Version mismatches shouldn't cause errors, but should not use the
     // serialized entries
     ASSERT_EQ(OK, mBC2->unflatten(flat, size));
     delete[] flat;

     // The version mismatch should cause the unflatten to result in an empty
     // cache
     ASSERT_EQ(size_t(0), mBC2->get("abcd", 4, buf, 4));
 }

 TEST_P(BlobCacheFlattenTest, UnflattenCatchesBufferTooSmall) {
     unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
     mBC->set("abcd", 4, "efgh", 4);

     size_t size = mBC->getFlattenedSize();
     uint8_t* flat = new uint8_t[size];
     ASSERT_EQ(OK, mBC->flatten(flat, size));

     // A buffer truncation shouldt cause an error
     // ASSERT_EQ(BAD_VALUE, mBC2->unflatten(flat, size-1));
     // TODO: The above appears to fail because getFlattenedSize() is
     // conservative.
     delete[] flat;

     // The error should cause the unflatten to result in an empty cache
     ASSERT_EQ(size_t(0), mBC2->get("abcd", 4, buf, 4));
 }

 }  // namespace android
	/*
	** Copyright 2011, The Android Open Source Project
	**
	** Licensed under the Apache License, Version 2.0 (the "License");
	** you may not use this file except in compliance with the License.
	** You may obtain a copy of the License at
	**
	** http://www.apache.org/licenses/LICENSE-2.0
	**
	** Unless required by applicable law or agreed to in writing, software
	** distributed under the License is distributed on an "AS IS" BASIS,
	** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	** See the License for the specific language governing permissions and
	** limitations under the License.
	*/

	#include <fcntl.h>
	#include <stdio.h>
	#include <stdlib.h>

	#include <algorithm>
	#include <memory>
	#include <numeric>
	#include <random>

	#include <gtest/gtest.h>

	#include "BlobCache.h"

	namespace android {

	template <typename T>
	using sp = std::shared_ptr<T>;

	class BlobCacheTest : public ::testing::TestWithParam<BlobCache::Policy> {
	protected:
	enum { OK = 0, BAD_VALUE = -EINVAL };

	enum {
	MAX_KEY_SIZE = 6,
	MAX_VALUE_SIZE = 8,
	MAX_TOTAL_SIZE = 13,
	};

	virtual void SetUp() {
	mBC.reset(new BlobCache(MAX_KEY_SIZE, MAX_VALUE_SIZE, MAX_TOTAL_SIZE, GetParam()));
	}

	virtual void TearDown() { mBC.reset(); }

	std::unique_ptr<BlobCache> mBC;
	};

	INSTANTIATE_TEST_SUITE_P(
	Policy, BlobCacheTest,
	::testing::Values(
	BlobCache::Policy(BlobCache::Select::RANDOM, BlobCache::Capacity::HALVE),
	BlobCache::Policy(BlobCache::Select::LRU, BlobCache::Capacity::HALVE),

	BlobCache::Policy(BlobCache::Select::RANDOM, BlobCache::Capacity::FIT),
	BlobCache::Policy(BlobCache::Select::LRU, BlobCache::Capacity::FIT),

	BlobCache::Policy(BlobCache::Select::RANDOM, BlobCache::Capacity::FIT_HALVE),
	BlobCache::Policy(BlobCache::Select::LRU, BlobCache::Capacity::FIT_HALVE)));

	TEST_P(BlobCacheTest, CacheSingleValueSucceeds) {
	unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
	mBC->set("abcd", 4, "efgh", 4);
	ASSERT_EQ(size_t(4), mBC->get("abcd", 4, buf, 4));
	ASSERT_EQ('e', buf[0]);
	ASSERT_EQ('f', buf[1]);
	ASSERT_EQ('g', buf[2]);
	ASSERT_EQ('h', buf[3]);
	}

	TEST_P(BlobCacheTest, CacheTwoValuesSucceeds) {
	unsigned char buf[2] = {0xee, 0xee};
	mBC->set("ab", 2, "cd", 2);
	mBC->set("ef", 2, "gh", 2);
	ASSERT_EQ(size_t(2), mBC->get("ab", 2, buf, 2));
	ASSERT_EQ('c', buf[0]);
	ASSERT_EQ('d', buf[1]);
	ASSERT_EQ(size_t(2), mBC->get("ef", 2, buf, 2));
	ASSERT_EQ('g', buf[0]);
	ASSERT_EQ('h', buf[1]);
	}

	TEST_P(BlobCacheTest, CacheTwoValuesMallocSucceeds) {
	unsigned char* bufPtr;
	mBC->set("ab", 2, "cd", 2);
	mBC->set("ef", 2, "gh", 2);

	bufPtr = nullptr;
	ASSERT_EQ(size_t(2), mBC->get("ab", 2, &bufPtr, malloc));
	ASSERT_NE(nullptr, bufPtr);
	ASSERT_EQ('c', bufPtr[0]);
	ASSERT_EQ('d', bufPtr[1]);
	free(bufPtr);

	bufPtr = nullptr;
	ASSERT_EQ(size_t(2), mBC->get("ef", 2, &bufPtr, malloc));
	ASSERT_NE(nullptr, bufPtr);
	ASSERT_EQ('g', bufPtr[0]);
	ASSERT_EQ('h', bufPtr[1]);
	free(bufPtr);
	}

	TEST_P(BlobCacheTest, GetOnlyWritesInsideBounds) {
	unsigned char buf[6] = {0xee, 0xee, 0xee, 0xee, 0xee, 0xee};
	mBC->set("abcd", 4, "efgh", 4);
	ASSERT_EQ(size_t(4), mBC->get("abcd", 4, buf + 1, 4));
	ASSERT_EQ(0xee, buf[0]);
	ASSERT_EQ('e', buf[1]);
	ASSERT_EQ('f', buf[2]);
	ASSERT_EQ('g', buf[3]);
	ASSERT_EQ('h', buf[4]);
	ASSERT_EQ(0xee, buf[5]);
	}

	TEST_P(BlobCacheTest, GetOnlyWritesIfBufferIsLargeEnough) {
	unsigned char buf[3] = {0xee, 0xee, 0xee};
	mBC->set("abcd", 4, "efgh", 4);
	ASSERT_EQ(size_t(4), mBC->get("abcd", 4, buf, 3));
	ASSERT_EQ(0xee, buf[0]);
	ASSERT_EQ(0xee, buf[1]);
	ASSERT_EQ(0xee, buf[2]);
	}

	TEST_P(BlobCacheTest, GetWithFailedAllocator) {
	unsigned char buf[3] = {0xee, 0xee, 0xee};
	mBC->set("abcd", 4, "efgh", 4);

	// If allocator fails, verify that we set the value pointer to
	// nullptr, and that we do not modify the buffer that the value
	// pointer originally pointed to.
	unsigned char* bufPtr = &buf[0];
	ASSERT_EQ(size_t(4), mBC->get("abcd", 4, &bufPtr, [](size_t) -> void* { return nullptr; }));
	ASSERT_EQ(nullptr, bufPtr);
	ASSERT_EQ(0xee, buf[0]);
	ASSERT_EQ(0xee, buf[1]);
	ASSERT_EQ(0xee, buf[2]);
	}

	TEST_P(BlobCacheTest, GetDoesntAccessNullBuffer) {
	mBC->set("abcd", 4, "efgh", 4);
	ASSERT_EQ(size_t(4), mBC->get("abcd", 4, NULL, 0));
	}

	TEST_P(BlobCacheTest, MultipleSetsCacheLatestValue) {
	unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
	mBC->set("abcd", 4, "efgh", 4);
	mBC->set("abcd", 4, "ijkl", 4);
	ASSERT_EQ(size_t(4), mBC->get("abcd", 4, buf, 4));
	ASSERT_EQ('i', buf[0]);
	ASSERT_EQ('j', buf[1]);
	ASSERT_EQ('k', buf[2]);
	ASSERT_EQ('l', buf[3]);
	}

	TEST_P(BlobCacheTest, SecondSetKeepsFirstValueIfTooLarge) {
	unsigned char buf[MAX_VALUE_SIZE + 1] = {0xee, 0xee, 0xee, 0xee};
	mBC->set("abcd", 4, "efgh", 4);
	mBC->set("abcd", 4, buf, MAX_VALUE_SIZE + 1);
	ASSERT_EQ(size_t(4), mBC->get("abcd", 4, buf, 4));
	ASSERT_EQ('e', buf[0]);
	ASSERT_EQ('f', buf[1]);
	ASSERT_EQ('g', buf[2]);
	ASSERT_EQ('h', buf[3]);
	}

	TEST_P(BlobCacheTest, DoesntCacheIfKeyIsTooBig) {
	char key[MAX_KEY_SIZE + 1];
	unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
	for (int i = 0; i < MAX_KEY_SIZE + 1; i++) {
	key[i] = 'a';
	}
	mBC->set(key, MAX_KEY_SIZE + 1, "bbbb", 4);

	ASSERT_EQ(size_t(0), mBC->get(key, MAX_KEY_SIZE + 1, buf, 4));
	ASSERT_EQ(0xee, buf[0]);
	ASSERT_EQ(0xee, buf[1]);
	ASSERT_EQ(0xee, buf[2]);
	ASSERT_EQ(0xee, buf[3]);

	// If key is too large, verify that we do not call the allocator,
	// that we set the value pointer to nullptr, and that we do not
	// modify the buffer that the value pointer originally pointed to.
	unsigned char* bufPtr = &buf[0];
	bool calledAlloc = false;
	ASSERT_EQ(size_t(0), mBC->get(key, MAX_KEY_SIZE + 1, &bufPtr, [&calledAlloc](size_t) -> void* {
	calledAlloc = true;
	return nullptr;
	}));
	ASSERT_EQ(false, calledAlloc);
	ASSERT_EQ(nullptr, bufPtr);
	ASSERT_EQ(0xee, buf[0]);
	ASSERT_EQ(0xee, buf[1]);
	ASSERT_EQ(0xee, buf[2]);
	ASSERT_EQ(0xee, buf[3]);
	}

	TEST_P(BlobCacheTest, DoesntCacheIfValueIsTooBig) {
	unsigned char buf[MAX_VALUE_SIZE + 1];
	for (int i = 0; i < MAX_VALUE_SIZE + 1; i++) {
	buf[i] = 'b';
	}
	mBC->set("abcd", 4, buf, MAX_VALUE_SIZE + 1);
	for (int i = 0; i < MAX_VALUE_SIZE + 1; i++) {
	buf[i] = 0xee;
	}
	ASSERT_EQ(size_t(0), mBC->get("abcd", 4, buf, MAX_VALUE_SIZE + 1));
	for (int i = 0; i < MAX_VALUE_SIZE + 1; i++) {
	SCOPED_TRACE(i);
	ASSERT_EQ(0xee, buf[i]);
	}
	}

	TEST_P(BlobCacheTest, DoesntCacheIfKeyValuePairIsTooBig) {
	// Check a testing assumptions
	ASSERT_TRUE(MAX_TOTAL_SIZE < MAX_KEY_SIZE + MAX_VALUE_SIZE);
	ASSERT_TRUE(MAX_KEY_SIZE < MAX_TOTAL_SIZE);

	enum { bufSize = MAX_TOTAL_SIZE - MAX_KEY_SIZE + 1 };

	char key[MAX_KEY_SIZE];
	char buf[bufSize];
	for (int i = 0; i < MAX_KEY_SIZE; i++) {
	key[i] = 'a';
	}
	for (int i = 0; i < bufSize; i++) {
	buf[i] = 'b';
	}

	mBC->set(key, MAX_KEY_SIZE, buf, MAX_VALUE_SIZE);
	ASSERT_EQ(size_t(0), mBC->get(key, MAX_KEY_SIZE, NULL, 0));
	}

	TEST_P(BlobCacheTest, CacheMaxKeySizeSucceeds) {
	char key[MAX_KEY_SIZE];
	unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
	for (int i = 0; i < MAX_KEY_SIZE; i++) {
	key[i] = 'a';
	}
	mBC->set(key, MAX_KEY_SIZE, "wxyz", 4);
	ASSERT_EQ(size_t(4), mBC->get(key, MAX_KEY_SIZE, buf, 4));
	ASSERT_EQ('w', buf[0]);
	ASSERT_EQ('x', buf[1]);
	ASSERT_EQ('y', buf[2]);
	ASSERT_EQ('z', buf[3]);
	}

	TEST_P(BlobCacheTest, CacheMaxValueSizeSucceeds) {
	char buf[MAX_VALUE_SIZE];
	for (int i = 0; i < MAX_VALUE_SIZE; i++) {
	buf[i] = 'b';
	}
	mBC->set("abcd", 4, buf, MAX_VALUE_SIZE);
	for (int i = 0; i < MAX_VALUE_SIZE; i++) {
	buf[i] = 0xee;
	}
	ASSERT_EQ(size_t(MAX_VALUE_SIZE), mBC->get("abcd", 4, buf, MAX_VALUE_SIZE));
	for (int i = 0; i < MAX_VALUE_SIZE; i++) {
	SCOPED_TRACE(i);
	ASSERT_EQ('b', buf[i]);
	}
	}

	TEST_P(BlobCacheTest, CacheMaxKeyValuePairSizeSucceeds) {
	// Check a testing assumption
	ASSERT_TRUE(MAX_KEY_SIZE < MAX_TOTAL_SIZE);

	enum { bufSize = MAX_TOTAL_SIZE - MAX_KEY_SIZE };

	char key[MAX_KEY_SIZE];
	char buf[bufSize];
	for (int i = 0; i < MAX_KEY_SIZE; i++) {
	key[i] = 'a';
	}
	for (int i = 0; i < bufSize; i++) {
	buf[i] = 'b';
	}

	mBC->set(key, MAX_KEY_SIZE, buf, bufSize);
	ASSERT_EQ(size_t(bufSize), mBC->get(key, MAX_KEY_SIZE, NULL, 0));
	}

	TEST_P(BlobCacheTest, CacheMinKeyAndValueSizeSucceeds) {
	unsigned char buf[1] = {0xee};
	mBC->set("x", 1, "y", 1);
	ASSERT_EQ(size_t(1), mBC->get("x", 1, buf, 1));
	ASSERT_EQ('y', buf[0]);
	}

	TEST_P(BlobCacheTest, CacheSizeDoesntExceedTotalLimit) {
	for (int i = 0; i < 256; i++) {
	uint8_t k = i;
	mBC->set(&k, 1, "x", 1);
	}
	int numCached = 0;
	for (int i = 0; i < 256; i++) {
	uint8_t k = i;
	if (mBC->get(&k, 1, NULL, 0) == 1) {
	numCached++;
	}
	}
	ASSERT_GE(MAX_TOTAL_SIZE / 2, numCached);
	}

	TEST_P(BlobCacheTest, ExceedingTotalLimitHalvesCacheSize) {
	if (GetParam().second == BlobCache::Capacity::FIT)
	return; // test doesn't apply for this policy

	// Fill up the entire cache with 1 char key/value pairs.
	const int maxEntries = MAX_TOTAL_SIZE / 2;
	for (int i = 0; i < maxEntries; i++) {
	uint8_t k = i;
	mBC->set(&k, 1, "x", 1);
	}
	// Insert one more entry, causing a cache overflow.
	{
	uint8_t k = maxEntries;
	mBC->set(&k, 1, "x", 1);
	}
	// Count the number of entries in the cache; and check which
	// entries they are.
	int numCached = 0;
	for (int i = 0; i < maxEntries + 1; i++) {
	uint8_t k = i;
	bool found = (mBC->get(&k, 1, NULL, 0) == 1);
	if (found) numCached++;
	if (GetParam().first == BlobCache::Select::LRU) {
	SCOPED_TRACE(i);
	ASSERT_EQ(found, i >= maxEntries / 2);
	}
	}
	ASSERT_EQ(maxEntries / 2 + 1, numCached);
	}

	TEST_P(BlobCacheTest, ExceedingTotalLimitJustFitsSmallEntry) {
	if (GetParam().second != BlobCache::Capacity::FIT)
	return; // test doesn't apply for this policy

	// Fill up the entire cache with 1 char key/value pairs.
	const int maxEntries = MAX_TOTAL_SIZE / 2;
	for (int i = 0; i < maxEntries; i++) {
	uint8_t k = i;
	mBC->set(&k, 1, "x", 1);
	}
	// Insert one more entry, causing a cache overflow.
	{
	uint8_t k = maxEntries;
	mBC->set(&k, 1, "x", 1);
	}
	// Count the number of entries in the cache.
	int numCached = 0;
	for (int i = 0; i < maxEntries + 1; i++) {
	uint8_t k = i;
	if (mBC->get(&k, 1, NULL, 0) == 1) numCached++;
	}
	ASSERT_EQ(maxEntries, numCached);
	}

	// Also see corresponding test in nnCache_test.cpp
	TEST_P(BlobCacheTest, ExceedingTotalLimitFitsBigEntry) {
	// Fill up the entire cache with 1 char key/value pairs.
	const int maxEntries = MAX_TOTAL_SIZE / 2;
	for (int i = 0; i < maxEntries; i++) {
	uint8_t k = i;
	mBC->set(&k, 1, "x", 1);
	}
	// Insert one more entry, causing a cache overflow.
	const int bigValueSize = std::min((MAX_TOTAL_SIZE * 3) / 4 - 1, int(MAX_VALUE_SIZE));
	ASSERT_GT(bigValueSize + 1, MAX_TOTAL_SIZE / 2); // Check testing assumption
	{
	unsigned char buf[MAX_VALUE_SIZE];
	for (int i = 0; i < bigValueSize; i++) buf[i] = 0xee;
	uint8_t k = maxEntries;
	mBC->set(&k, 1, buf, bigValueSize);
	}
	// Count the number and size of entries in the cache.
	int numCached = 0;
	size_t sizeCached = 0;
	for (int i = 0; i < maxEntries + 1; i++) {
	uint8_t k = i;
	size_t size = mBC->get(&k, 1, NULL, 0);
	if (size) {
	numCached++;
	sizeCached += (size + 1);
	}
	}
	switch (GetParam().second) {
	case BlobCache::Capacity::HALVE:
	// New value is too big for this cleaning algorithm. So
	// we cleaned the cache, but did not insert the new value.
	ASSERT_EQ(maxEntries / 2, numCached);
	ASSERT_EQ(size_t((maxEntries / 2) * 2), sizeCached);
	break;
	case BlobCache::Capacity::FIT:
	case BlobCache::Capacity::FIT_HALVE: {
	// We had to clean more than half the cache to fit the new
	// value.
	const int initialNumEntries = maxEntries;
	const int initialSizeCached = initialNumEntries * 2;
	const int initialFreeSpace = MAX_TOTAL_SIZE - initialSizeCached;

	// (bigValueSize + 1) = value size + key size
	// trailing "+ 1" is in order to round up
	// "/ 2" is because initial entries are size 2 (1 byte key, 1 byte value)
	const int cleanNumEntries = ((bigValueSize + 1) - initialFreeSpace + 1) / 2;

	const int cleanSpace = cleanNumEntries * 2;
	const int postCleanNumEntries = initialNumEntries - cleanNumEntries;
	const int postCleanSizeCached = initialSizeCached - cleanSpace;
	ASSERT_EQ(postCleanNumEntries + 1, numCached);
	ASSERT_EQ(size_t(postCleanSizeCached + bigValueSize + 1), sizeCached);

	break;
	}
	default:
	FAIL() << "Unknown Capacity value";
	}
	}

	TEST_P(BlobCacheTest, FailedGetWithAllocator) {
	// If get doesn't find anything, verify that we do not call the
	// allocator, that we set the value pointer to nullptr, and that
	// we do not modify the buffer that the value pointer originally
	// pointed to.
	unsigned char buf[1] = {0xee};
	unsigned char* bufPtr = &buf[0];
	bool calledAlloc = false;
	ASSERT_EQ(size_t(0), mBC->get("a", 1, &bufPtr, [&calledAlloc](size_t) -> void* {
	calledAlloc = true;
	return nullptr;
	}));
	ASSERT_EQ(false, calledAlloc);
	ASSERT_EQ(nullptr, bufPtr);
	ASSERT_EQ(0xee, buf[0]);
	}

	TEST_P(BlobCacheTest, ExceedingTotalLimitRemovesLRUEntries) {
	if (GetParam().first != BlobCache::Select::LRU) return; // test doesn't apply for this policy

	// Fill up the entire cache with 1 char key/value pairs.
	static const int maxEntries = MAX_TOTAL_SIZE / 2;
	for (int i = 0; i < maxEntries; i++) {
	uint8_t k = i;
	mBC->set(&k, 1, "x", 1);
	}

	// Access entries in some known pseudorandom order.
	int accessSequence[maxEntries];
	std::iota(&accessSequence[0], &accessSequence[maxEntries], 0);
	std::mt19937 randomEngine(MAX_TOTAL_SIZE /* seed */);
	std::shuffle(&accessSequence[0], &accessSequence[maxEntries], randomEngine);
	for (int i = 0; i < maxEntries; i++) {
	uint8_t k = accessSequence[i];
	uint8_t buf[1];
	// If we were to pass NULL to get() as the value pointer, this
	// won't count as an access for LRU purposes.
	mBC->get(&k, 1, buf, 1);
	}

	// Insert one more entry, causing a cache overflow.
	{
	uint8_t k = maxEntries;
	mBC->set(&k, 1, "x", 1);
	}

	// Check which entries are in the cache. We expect to see the
	// "one more entry" we just added, and also the most-recently
	// accessed (according to accessSequence). That is, we should
	// find exactly the entries with the following keys:
	// . maxEntries
	// . accessSequence[j..maxEntries-1] for some 0 <= j < maxEntries
	uint8_t k = maxEntries;
	ASSERT_EQ(size_t(1), mBC->get(&k, 1, NULL, 0));
	bool foundAny = false;
	for (int i = 0; i < maxEntries; i++) {
	uint8_t k = accessSequence[i];
	bool found = (mBC->get(&k, 1, NULL, 0) == 1);
	if (foundAny == found) continue;
	if (!foundAny) {
	// found == true, so we just discovered j == i
	foundAny = true;
	} else {
	// foundAny == true, found == false -- oops
	FAIL() << "found [" << i - 1 << "]th entry but not [" << i << "]th entry";
	}
	}
	}

	class BlobCacheFlattenTest : public BlobCacheTest {
	protected:
	virtual void SetUp() {
	BlobCacheTest::SetUp();
	mBC2.reset(new BlobCache(MAX_KEY_SIZE, MAX_VALUE_SIZE, MAX_TOTAL_SIZE, GetParam()));
	}

	virtual void TearDown() {
	mBC2.reset();
	BlobCacheTest::TearDown();
	}

	void roundTrip() {
	size_t size = mBC->getFlattenedSize();
	uint8_t* flat = new uint8_t[size];
	ASSERT_EQ(OK, mBC->flatten(flat, size));
	ASSERT_EQ(OK, mBC2->unflatten(flat, size));
	delete[] flat;
	}

	sp<BlobCache> mBC2;
	};

	INSTANTIATE_TEST_SUITE_P(
	Policy, BlobCacheFlattenTest,
	::testing::Values(
	BlobCache::Policy(BlobCache::Select::RANDOM, BlobCache::Capacity::HALVE),
	BlobCache::Policy(BlobCache::Select::LRU, BlobCache::Capacity::HALVE),

	BlobCache::Policy(BlobCache::Select::RANDOM, BlobCache::Capacity::FIT),
	BlobCache::Policy(BlobCache::Select::LRU, BlobCache::Capacity::FIT),

	BlobCache::Policy(BlobCache::Select::RANDOM, BlobCache::Capacity::FIT_HALVE),
	BlobCache::Policy(BlobCache::Select::LRU, BlobCache::Capacity::FIT_HALVE)));

	TEST_P(BlobCacheFlattenTest, FlattenOneValue) {
	unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
	mBC->set("abcd", 4, "efgh", 4);
	roundTrip();
	ASSERT_EQ(size_t(4), mBC2->get("abcd", 4, buf, 4));
	ASSERT_EQ('e', buf[0]);
	ASSERT_EQ('f', buf[1]);
	ASSERT_EQ('g', buf[2]);
	ASSERT_EQ('h', buf[3]);
	}

	TEST_P(BlobCacheFlattenTest, FlattenFullCache) {
	// Fill up the entire cache with 1 char key/value pairs.
	const int maxEntries = MAX_TOTAL_SIZE / 2;
	for (int i = 0; i < maxEntries; i++) {
	uint8_t k = i;
	mBC->set(&k, 1, &k, 1);
	}

	roundTrip();

	// Verify the deserialized cache
	for (int i = 0; i < maxEntries; i++) {
	uint8_t k = i;
	uint8_t v = 0xee;
	ASSERT_EQ(size_t(1), mBC2->get(&k, 1, &v, 1));
	ASSERT_EQ(k, v);
	}
	}

	TEST_P(BlobCacheFlattenTest, FlattenDoesntChangeCache) {
	// Fill up the entire cache with 1 char key/value pairs.
	const int maxEntries = MAX_TOTAL_SIZE / 2;
	for (int i = 0; i < maxEntries; i++) {
	uint8_t k = i;
	mBC->set(&k, 1, &k, 1);
	}

	size_t size = mBC->getFlattenedSize();
	uint8_t* flat = new uint8_t[size];
	ASSERT_EQ(OK, mBC->flatten(flat, size));
	delete[] flat;

	// Verify the cache that we just serialized
	for (int i = 0; i < maxEntries; i++) {
	uint8_t k = i;
	uint8_t v = 0xee;
	ASSERT_EQ(size_t(1), mBC->get(&k, 1, &v, 1));
	ASSERT_EQ(k, v);
	}
	}

	TEST_P(BlobCacheFlattenTest, FlattenCatchesBufferTooSmall) {
	// Fill up the entire cache with 1 char key/value pairs.
	const int maxEntries = MAX_TOTAL_SIZE / 2;
	for (int i = 0; i < maxEntries; i++) {
	uint8_t k = i;
	mBC->set(&k, 1, &k, 1);
	}

	size_t size = mBC->getFlattenedSize() - 1;
	uint8_t* flat = new uint8_t[size];
	// ASSERT_EQ(BAD_VALUE, mBC->flatten(flat, size));
	// TODO: The above fails. I expect this is so because getFlattenedSize()
	// overstimates the size by using PROPERTY_VALUE_MAX.
	delete[] flat;
	}

	TEST_P(BlobCacheFlattenTest, UnflattenCatchesBadMagic) {
	unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
	mBC->set("abcd", 4, "efgh", 4);

	size_t size = mBC->getFlattenedSize();
	uint8_t* flat = new uint8_t[size];
	ASSERT_EQ(OK, mBC->flatten(flat, size));
	flat[1] = ~flat[1];

	// Bad magic should cause an error.
	ASSERT_EQ(BAD_VALUE, mBC2->unflatten(flat, size));
	delete[] flat;

	// The error should cause the unflatten to result in an empty cache
	ASSERT_EQ(size_t(0), mBC2->get("abcd", 4, buf, 4));
	}

	TEST_P(BlobCacheFlattenTest, UnflattenCatchesBadBlobCacheVersion) {
	unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
	mBC->set("abcd", 4, "efgh", 4);

	size_t size = mBC->getFlattenedSize();
	uint8_t* flat = new uint8_t[size];
	ASSERT_EQ(OK, mBC->flatten(flat, size));
	flat[5] = ~flat[5];

	// Version mismatches shouldn't cause errors, but should not use the
	// serialized entries
	ASSERT_EQ(OK, mBC2->unflatten(flat, size));
	delete[] flat;

	// The version mismatch should cause the unflatten to result in an empty
	// cache
	ASSERT_EQ(size_t(0), mBC2->get("abcd", 4, buf, 4));
	}

	TEST_P(BlobCacheFlattenTest, UnflattenCatchesBadBlobCacheDeviceVersion) {
	unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
	mBC->set("abcd", 4, "efgh", 4);

	size_t size = mBC->getFlattenedSize();
	uint8_t* flat = new uint8_t[size];
	ASSERT_EQ(OK, mBC->flatten(flat, size));
	flat[10] = ~flat[10];

	// Version mismatches shouldn't cause errors, but should not use the
	// serialized entries
	ASSERT_EQ(OK, mBC2->unflatten(flat, size));
	delete[] flat;

	// The version mismatch should cause the unflatten to result in an empty
	// cache
	ASSERT_EQ(size_t(0), mBC2->get("abcd", 4, buf, 4));
	}

	TEST_P(BlobCacheFlattenTest, UnflattenCatchesBufferTooSmall) {
	unsigned char buf[4] = {0xee, 0xee, 0xee, 0xee};
	mBC->set("abcd", 4, "efgh", 4);

	size_t size = mBC->getFlattenedSize();
	uint8_t* flat = new uint8_t[size];
	ASSERT_EQ(OK, mBC->flatten(flat, size));

	// A buffer truncation shouldt cause an error
	// ASSERT_EQ(BAD_VALUE, mBC2->unflatten(flat, size-1));
	// TODO: The above appears to fail because getFlattenedSize() is
	// conservative.
	delete[] flat;

	// The error should cause the unflatten to result in an empty cache
	ASSERT_EQ(size_t(0), mBC2->get("abcd", 4, buf, 4));
	}

	} // namespace android