1  // Copyright (c) 2012 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 "table/filter_block.h"
  6  
  7  #include "leveldb/filter_policy.h"
  8  #include "util/coding.h"
  9  #include "util/hash.h"
 10  #include "util/logging.h"
 11  #include "util/testharness.h"
 12  #include "util/testutil.h"
 13  
 14  namespace leveldb {
 15  
 16  // For testing: emit an array with one hash value per key
 17  class TestHashFilter : public FilterPolicy {
 18   public:
 19    const char* Name() const override { return "TestHashFilter"; }
 20  
 21    void CreateFilter(const Slice* keys, int n, std::string* dst) const override {
 22      for (int i = 0; i < n; i++) {
 23        uint32_t h = Hash(keys[i].data(), keys[i].size(), 1);
 24        PutFixed32(dst, h);
 25      }
 26    }
 27  
 28    bool KeyMayMatch(const Slice& key, const Slice& filter) const override {
 29      uint32_t h = Hash(key.data(), key.size(), 1);
 30      for (size_t i = 0; i + 4 <= filter.size(); i += 4) {
 31        if (h == DecodeFixed32(filter.data() + i)) {
 32          return true;
 33        }
 34      }
 35      return false;
 36    }
 37  };
 38  
 39  class FilterBlockTest {
 40   public:
 41    TestHashFilter policy_;
 42  };
 43  
 44  TEST(FilterBlockTest, EmptyBuilder) {
 45    FilterBlockBuilder builder(&policy_);
 46    Slice block = builder.Finish();
 47    ASSERT_EQ("\\x00\\x00\\x00\\x00\\x0b", EscapeString(block));
 48    FilterBlockReader reader(&policy_, block);
 49    ASSERT_TRUE(reader.KeyMayMatch(0, "foo"));
 50    ASSERT_TRUE(reader.KeyMayMatch(100000, "foo"));
 51  }
 52  
 53  TEST(FilterBlockTest, SingleChunk) {
 54    FilterBlockBuilder builder(&policy_);
 55    builder.StartBlock(100);
 56    builder.AddKey("foo");
 57    builder.AddKey("bar");
 58    builder.AddKey("box");
 59    builder.StartBlock(200);
 60    builder.AddKey("box");
 61    builder.StartBlock(300);
 62    builder.AddKey("hello");
 63    Slice block = builder.Finish();
 64    FilterBlockReader reader(&policy_, block);
 65    ASSERT_TRUE(reader.KeyMayMatch(100, "foo"));
 66    ASSERT_TRUE(reader.KeyMayMatch(100, "bar"));
 67    ASSERT_TRUE(reader.KeyMayMatch(100, "box"));
 68    ASSERT_TRUE(reader.KeyMayMatch(100, "hello"));
 69    ASSERT_TRUE(reader.KeyMayMatch(100, "foo"));
 70    ASSERT_TRUE(!reader.KeyMayMatch(100, "missing"));
 71    ASSERT_TRUE(!reader.KeyMayMatch(100, "other"));
 72  }
 73  
 74  TEST(FilterBlockTest, MultiChunk) {
 75    FilterBlockBuilder builder(&policy_);
 76  
 77    // First filter
 78    builder.StartBlock(0);
 79    builder.AddKey("foo");
 80    builder.StartBlock(2000);
 81    builder.AddKey("bar");
 82  
 83    // Second filter
 84    builder.StartBlock(3100);
 85    builder.AddKey("box");
 86  
 87    // Third filter is empty
 88  
 89    // Last filter
 90    builder.StartBlock(9000);
 91    builder.AddKey("box");
 92    builder.AddKey("hello");
 93  
 94    Slice block = builder.Finish();
 95    FilterBlockReader reader(&policy_, block);
 96  
 97    // Check first filter
 98    ASSERT_TRUE(reader.KeyMayMatch(0, "foo"));
 99    ASSERT_TRUE(reader.KeyMayMatch(2000, "bar"));
100    ASSERT_TRUE(!reader.KeyMayMatch(0, "box"));
101    ASSERT_TRUE(!reader.KeyMayMatch(0, "hello"));
102  
103    // Check second filter
104    ASSERT_TRUE(reader.KeyMayMatch(3100, "box"));
105    ASSERT_TRUE(!reader.KeyMayMatch(3100, "foo"));
106    ASSERT_TRUE(!reader.KeyMayMatch(3100, "bar"));
107    ASSERT_TRUE(!reader.KeyMayMatch(3100, "hello"));
108  
109    // Check third filter (empty)
110    ASSERT_TRUE(!reader.KeyMayMatch(4100, "foo"));
111    ASSERT_TRUE(!reader.KeyMayMatch(4100, "bar"));
112    ASSERT_TRUE(!reader.KeyMayMatch(4100, "box"));
113    ASSERT_TRUE(!reader.KeyMayMatch(4100, "hello"));
114  
115    // Check last filter
116    ASSERT_TRUE(reader.KeyMayMatch(9000, "box"));
117    ASSERT_TRUE(reader.KeyMayMatch(9000, "hello"));
118    ASSERT_TRUE(!reader.KeyMayMatch(9000, "foo"));
119    ASSERT_TRUE(!reader.KeyMayMatch(9000, "bar"));
120  }
121  
122  }  // namespace leveldb
123  
124  int main(int argc, char** argv) { return leveldb::test::RunAllTests(); }