Finish conversion from bloom filter to prefix set in safe browsing.

chrome/browser/safe_browsing/bloom_filter.h

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-//
-// A simple bloom filter. It uses a large number (20) of hashes to reduce the
-// possibility of false positives. The bloom filter's hashing uses random keys
-// in order to minimize the chance that a false positive for one user is a false
-// positive for all.
-//
-// The bloom filter manages it serialization to disk with the following file
-// format:
-//         4 byte version number
-//         4 byte number of hash keys (n)
-//     n * 8 bytes of hash keys
-// Remaining bytes are the filter data.
-
-#ifndef CHROME_BROWSER_SAFE_BROWSING_BLOOM_FILTER_H_
-#define CHROME_BROWSER_SAFE_BROWSING_BLOOM_FILTER_H_
-
-#include <vector>
-
-#include "base/gtest_prod_util.h"
-#include "base/memory/ref_counted.h"
-#include "base/memory/scoped_ptr.h"
-#include "chrome/browser/safe_browsing/safe_browsing_util.h"
-
-class FilePath;
-
-class BloomFilter : public base::RefCountedThreadSafe<BloomFilter> {
- public:
-  typedef uint64 HashKey;
-  typedef std::vector<HashKey> HashKeys;
-
-  // Constructs an empty filter with the given size.
-  explicit BloomFilter(int bit_size);
-
-  // Constructs a filter from serialized data. This object owns the memory and
-  // will delete it on destruction.
-  BloomFilter(char* data, int size, const HashKeys& keys);
-
-  void Insert(SBPrefix hash);
-  bool Exists(SBPrefix hash) const;
-
-  const char* data() const { return data_.get(); }
-  int size() const { return byte_size_; }
-
-  // Loading and storing the filter from / to disk.
-  static BloomFilter* LoadFile(const FilePath& filter_name);
-  bool WriteFile(const FilePath& filter_name) const;
-
-  // How many bits to use per item. See the design doc for more information.
-  static const int kBloomFilterSizeRatio = 25;
-
-  // Force a minimum size on the bloom filter to prevent a high false positive
-  // hash request rate (in bytes).
-  static const int kBloomFilterMinSize = 250000;
-
-  // Force a maximum size on the bloom filter to avoid using too much memory
-  // (in bytes).
-  static const int kBloomFilterMaxSize = 3 * 1024 * 1024;
-
-  // Use the above constants to calculate an appropriate size to pass
-  // to the BloomFilter constructor based on the intended |key_count|.
-  // TODO(shess): This is very clunky.  It would be cleaner to have
-  // the constructor manage this, but at this time the unit and perf
-  // tests wish to make their own calculations.
-  static int FilterSizeForKeyCount(int key_count);
-
-  // Check whether the contents of the bloom filter have changed since
-  // construction.  Present while debugging PrefixSet.
-  bool CheckChecksum() const;
-
- private:
-  friend class base::RefCountedThreadSafe<BloomFilter>;
-  FRIEND_TEST_ALL_PREFIXES(SafeBrowsingBloomFilter, BloomFilterUse);
-  FRIEND_TEST_ALL_PREFIXES(SafeBrowsingBloomFilter, BloomFilterFile);
-
-  static const int kNumHashKeys = 20;
-  static const int kFileVersion = 1;
-
-  // Enumerate failures for histogramming purposes.  DO NOT CHANGE THE
-  // ORDERING OF THESE VALUES.
-  enum FailureType {
-    FAILURE_FILTER_READ_OPEN,
-    FAILURE_FILTER_READ_VERSION,
-    FAILURE_FILTER_READ_NUM_KEYS,
-    FAILURE_FILTER_READ_KEY,
-    FAILURE_FILTER_READ_DATA_MINSIZE,
-    FAILURE_FILTER_READ_DATA_MAXSIZE,
-    FAILURE_FILTER_READ_DATA_SHORT,
-    FAILURE_FILTER_READ_DATA,
-
-    // Memory space for histograms is determined by the max.  ALWAYS
-    // ADD NEW VALUES BEFORE THIS ONE.
-    FAILURE_FILTER_MAX
-  };
-
-  static void RecordFailure(FailureType failure_type);
-
-  ~BloomFilter();
-
-  int byte_size_;  // size in bytes
-  int bit_size_;   // size in bits
-  scoped_array<char> data_;
-
-  // Random keys used for hashing.
-  HashKeys hash_keys_;
-
-  // For debugging, used to verify that |hash_keys_| and |data_| have
-  // not changed other than via constructor or Insert().
-  uint32 checksum_;
-
-  DISALLOW_COPY_AND_ASSIGN(BloomFilter);
-};
-
-#endif  // CHROME_BROWSER_SAFE_BROWSING_BLOOM_FILTER_H_