components/metrics/serialization/metric_sample.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_METRICS_SERIALIZATION_METRIC_SAMPLE_H_
   6 #define COMPONENTS_METRICS_SERIALIZATION_METRIC_SAMPLE_H_
   7
   8 #include <string>
   9
  10 #include "base/gtest_prod_util.h"
  11 #include "base/macros.h"
  12 #include "base/memory/scoped_ptr.h"
  13
  14 namespace metrics {
  15
  16 // This class is used by libmetrics (ChromeOS) to serialize
  17 // and deserialize measurements to send them to a metrics sending service.
  18 // It is meant to be a simple container with serialization functions.
  19 class MetricSample {
  20  public:
  21   // Types of metric sample used.
  22   enum SampleType {
  23     CRASH,
  24     HISTOGRAM,
  25     LINEAR_HISTOGRAM,
  26     SPARSE_HISTOGRAM,
  27     USER_ACTION
  28   };
  29
  30   ~MetricSample();
  31
  32   // Returns true if the sample is valid (can be serialized without ambiguity).
  33   //
  34   // This function should be used to filter bad samples before serializing them.
  35   bool IsValid() const;
  36
  37   // Getters for type and name. All types of metrics have these so we do not
  38   // need to check the type.
  39   SampleType type() const { return type_; }
  40   const std::string& name() const { return name_; }
  41
  42   // Getters for sample, min, max, bucket_count.
  43   // Check the metric type to make sure the request make sense. (ex: a crash
  44   // sample does not have a bucket_count so we crash if we call bucket_count()
  45   // on it.)
  46   const int sample() const;
  47   const int min() const;
  48   const int max() const;
  49   const int bucket_count() const;
  50
  51   // Returns a serialized version of the sample.
  52   //
  53   // The serialized message for each type is:
  54   // crash: crash\0|name_|\0
  55   // user action: useraction\0|name_|\0
  56   // histogram: histogram\0|name_| |sample_| |min_| |max_| |bucket_count_|\0
  57   // sparsehistogram: sparsehistogram\0|name_| |sample_|\0
  58   // linearhistogram: linearhistogram\0|name_| |sample_| |max_|\0
  59   std::string ToString() const;
  60
  61   // Builds a crash sample.
  62   static scoped_ptr<MetricSample> CrashSample(const std::string& crash_name);
  63
  64   // Builds a histogram sample.
  65   static scoped_ptr<MetricSample> HistogramSample(
  66       const std::string& histogram_name,
  67       int sample,
  68       int min,
  69       int max,
  70       int bucket_count);
  71   // Deserializes a histogram sample.
  72   static scoped_ptr<MetricSample> ParseHistogram(const std::string& serialized);
  73
  74   // Builds a sparse histogram sample.
  75   static scoped_ptr<MetricSample> SparseHistogramSample(
  76       const std::string& histogram_name,
  77       int sample);
  78   // Deserializes a sparse histogram sample.
  79   static scoped_ptr<MetricSample> ParseSparseHistogram(
  80       const std::string& serialized);
  81
  82   // Builds a linear histogram sample.
  83   static scoped_ptr<MetricSample> LinearHistogramSample(
  84       const std::string& histogram_name,
  85       int sample,
  86       int max);
  87   // Deserializes a linear histogram sample.
  88   static scoped_ptr<MetricSample> ParseLinearHistogram(
  89       const std::string& serialized);
  90
  91   // Builds a user action sample.
  92   static scoped_ptr<MetricSample> UserActionSample(
  93       const std::string& action_name);
  94
  95   // Returns true if sample and this object represent the same sample (type,
  96   // name, sample, min, max, bucket_count match).
  97   bool IsEqual(const MetricSample& sample);
  98
  99  private:
 100   MetricSample(SampleType sample_type,
 101                const std::string& metric_name,
 102                const int sample,
 103                const int min,
 104                const int max,
 105                const int bucket_count);
 106
 107   const SampleType type_;
 108   const std::string name_;
 109   const int sample_;
 110   const int min_;
 111   const int max_;
 112   const int bucket_count_;
 113
 114   DISALLOW_COPY_AND_ASSIGN(MetricSample);
 115 };
 116
 117 }  // namespace metrics
 118
 119 #endif  // COMPONENTS_METRICS_SERIALIZATION_METRIC_SAMPLE_H_