components/rappor/sample.h

   1 // Copyright 2015 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_SAMPLE_H_
   6 #define COMPONENTS_RAPPOR_SAMPLE_H_
   7
   8 #include <map>
   9 #include <string>
  10
  11 #include "base/basictypes.h"
  12 #include "base/macros.h"
  13 #include "components/rappor/rappor_parameters.h"
  14
  15 namespace rappor {
  16
  17 class RapporReports;
  18 class RapporService;
  19 class TestSamplerFactory;
  20
  21 // Sample is a container for information about a single instance of some event
  22 // we are sending Rappor data about.  It may contain multiple different fields,
  23 // which describe different details of the event, and they will be sent in the
  24 // same Rappor report, enabling analysis of correlations between those fields.
  25 class Sample {
  26  public:
  27   ~Sample();
  28
  29   // Sets a string value field in this sample.
  30   void SetStringField(const std::string& field_name, const std::string& value);
  31
  32   // Sets a group of boolean flags as a field in this sample.
  33   // |flags| should be a set of boolean flags stored in the lowest |num_flags|
  34   // bits of |flags|.
  35   void SetFlagsField(const std::string& field_name,
  36                      uint64_t flags,
  37                      size_t num_flags);
  38
  39   // Generate randomized reports and store them in |reports|.
  40   void ExportMetrics(const std::string& secret,
  41                      const std::string& metric_name,
  42                      RapporReports* reports) const;
  43
  44   const RapporParameters& parameters() { return parameters_; }
  45
  46  private:
  47   friend class TestSamplerFactory;
  48   friend class RapporService;
  49
  50   // Constructs a sample.  Instead of calling this directly, call
  51   // RapporService::MakeSampleObj to create a sample.
  52   Sample(int32_t cohort_seed, const RapporParameters& parameters);
  53
  54   const RapporParameters parameters_;
  55
  56   // Offset used for bloom filter hash functions.
  57   uint32_t bloom_offset_;
  58
  59   // Size of each of the different fields, in bytes.
  60   std::map<std::string, size_t> sizes_;
  61
  62   // The non-randomized report values for each field.
  63   std::map<std::string, uint64_t> fields_;
  64
  65   DISALLOW_COPY_AND_ASSIGN(Sample);
  66 };
  67
  68 }  // namespace rappor
  69
  70 #endif  // COMPONENTS_RAPPOR_SAMPLE_H_