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 it's reporting level is >= the reporting level
  20 // passed in to RapporService::Start()
  21 enum ReportingLevel {
  22   // No metrics are reported at this level.
  23   REPORTING_DISABLED = 0,
  24   // Metrics suitable for broader populations.
  25   COARSE_LEVEL,
  26   // Metrics suitable for UMA opt-in users.
  27   FINE_LEVEL,
  28 };
  29
  30 // An object describing a rappor metric and the parameters used to generate it.
  31 //
  32 // For a full description of the rappor metrics, see
  33 // http://www.chromium.org/developers/design-documents/rappor
  34 struct RapporParameters {
  35   // Get a string representing the parameters, for DCHECK_EQ.
  36   std::string ToString() const;
  37
  38   // The maximum number of cohorts we divide clients into.
  39   static const int kMaxCohorts;
  40
  41   // The number of cohorts to divide the reports for this metric into.
  42   // This should divide kMaxCohorts evenly so that each cohort has an equal
  43   // probability of being assigned users.
  44   int num_cohorts;
  45
  46   // The number of bytes stored in the Bloom filter.
  47   int bloom_filter_size_bytes;
  48   // The number of hash functions used in the Bloom filter.
  49   int bloom_filter_hash_function_count;
  50
  51   // The probability that a bit will be redacted with fake data.
  52   Probability fake_prob;
  53   // The probability that a fake bit will be a one.
  54   Probability fake_one_prob;
  55
  56   // The probability that a one bit in the redacted data reports as one.
  57   Probability one_coin_prob;
  58   // The probability that a zero bit in the redacted data reports as one.
  59   Probability zero_coin_prob;
  60
  61   // The reporting level this metric is reported at.
  62   ReportingLevel reporting_level;
  63 };
  64
  65 }  // namespace rappor
  66
  67 #endif  // COMPONENTS_RAPPOR_RAPPOR_PARAMETERS_H_