components/rappor/sample.cc

   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 #include "components/rappor/sample.h"
   6
   7 #include <map>
   8 #include <string>
   9
  10 #include "base/logging.h"
  11 #include "components/metrics/metrics_hashes.h"
  12 #include "components/rappor/bloom_filter.h"
  13 #include "components/rappor/byte_vector_utils.h"
  14 #include "components/rappor/proto/rappor_metric.pb.h"
  15 #include "components/rappor/reports.h"
  16
  17 namespace rappor {
  18
  19 Sample::Sample(int32_t cohort_seed, const RapporParameters& parameters)
  20   : parameters_(parameters),
  21     bloom_offset_((cohort_seed % parameters_.num_cohorts) *
  22           parameters_.bloom_filter_hash_function_count) {
  23   // Must use bloom filter size that fits in uint64.
  24   DCHECK_LE(parameters_.bloom_filter_size_bytes, 8);
  25 }
  26
  27 Sample::~Sample() {
  28 }
  29
  30 void Sample::SetStringField(const std::string& field_name,
  31                             const std::string& value) {
  32   DVLOG(2) << "Recording sample \"" << value
  33            << "\" for sample metric field \"" << field_name << "\"";
  34   DCHECK_EQ(0u, sizes_[field_name]);
  35   fields_[field_name] = internal::GetBloomBits(
  36       parameters_.bloom_filter_size_bytes,
  37       parameters_.bloom_filter_hash_function_count,
  38       bloom_offset_,
  39       value);
  40   sizes_[field_name] = parameters_.bloom_filter_size_bytes;
  41 }
  42
  43 void Sample::SetFlagsField(const std::string& field_name,
  44                            uint64_t flags,
  45                            size_t num_flags) {
  46   DVLOG(2) << "Recording flags " << flags
  47            << " for sample metric field \"" << field_name << "\"";
  48   DCHECK_EQ(0u, sizes_[field_name]);
  49   DCHECK_GT(num_flags, 0u);
  50   DCHECK_LE(num_flags, 64u);
  51   DCHECK(num_flags == 64u || flags >> num_flags == 0);
  52   fields_[field_name] = flags;
  53   sizes_[field_name] = (num_flags + 7) / 8;
  54 }
  55
  56 void Sample::ExportMetrics(const std::string& secret,
  57                            const std::string& metric_name,
  58                            RapporReports* reports) const {
  59   for (const auto& kv : fields_) {
  60     uint64_t value = kv.second;
  61     const auto it = sizes_.find(kv.first);
  62     DCHECK(it != sizes_.end());
  63     size_t size = it->second;
  64     ByteVector value_bytes(size);
  65     Uint64ToByteVector(value, size, &value_bytes);
  66     ByteVector report_bytes = internal::GenerateReport(
  67         secret, parameters_, value_bytes);
  68
  69     RapporReports::Report* report = reports->add_report();
  70     report->set_name_hash(metrics::HashMetricName(
  71         metric_name + "." + kv.first));
  72     report->set_bits(std::string(report_bytes.begin(), report_bytes.end()));
  73     DVLOG(2) << "Exporting sample " << metric_name << "." << kv.first;
  74   }
  75 }
  76
  77 }  // namespace rappor