components/rappor/rappor_parameters.h

   1 // Copyright 2014 The Chromium 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.
   4
   5 #ifndef COMPONENTS_RAPPOR_RAPPOR_PARAMETERS_H_
   6 #define COMPONENTS_RAPPOR_RAPPOR_PARAMETERS_H_
   7
   8 #include <string>
   9
  10 namespace rappor {
  11
  12 enum Probability {
  13   PROBABILITY_75,    // 75%
  14   PROBABILITY_50,    // 50%
  15   PROBABILITY_25,    // 25%
  16 };
  17
  18
  19 // A metric is reported when its reporting group is in the set of groups
  20 // passed in to RapporService::Start()
  21 enum RecordingGroup {
  22   // Metrics for UMA users.
  23   UMA_RAPPOR_GROUP = 1 << 0,
  24   // Metrics related to SafeBrowsing, for SafeBrowsing users.
  25   SAFEBROWSING_RAPPOR_GROUP = 1 << 1,
  26 };
  27
  28 // An object describing a rappor metric and the parameters used to generate it.
  29 //
  30 // For a full description of the rappor metrics, see
  31 // http://www.chromium.org/developers/design-documents/rappor
  32 struct RapporParameters {
  33   // Get a string representing the parameters, for DCHECK_EQ.
  34   std::string ToString() const;
  35
  36   // The maximum number of cohorts we divide clients into.
  37   static const int kMaxCohorts;
  38
  39   // The number of cohorts to divide the reports for this metric into.
  40   // This should divide kMaxCohorts evenly so that each cohort has an equal
  41   // probability of being assigned users.
  42   int num_cohorts;
  43
  44   // The number of bytes stored in the Bloom filter.
  45   int bloom_filter_size_bytes;
  46   // The number of hash functions used in the Bloom filter.
  47   int bloom_filter_hash_function_count;
  48
  49   // The probability that a bit will be redacted with fake data.
  50   Probability fake_prob;
  51   // The probability that a fake bit will be a one.
  52   Probability fake_one_prob;
  53
  54   // The probability that a one bit in the redacted data reports as one.
  55   Probability one_coin_prob;
  56   // The probability that a zero bit in the redacted data reports as one.
  57   Probability zero_coin_prob;
  58
  59   // The reporting level this metric is reported at.
  60   RecordingGroup recording_group;
  61 };
  62
  63 }  // namespace rappor
  64
  65 #endif  // COMPONENTS_RAPPOR_RAPPOR_PARAMETERS_H_