base/metrics/sparse_histogram.h

   1 // Copyright (c) 2012 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 BASE_METRICS_SPARSE_HISTOGRAM_H_
   6 #define BASE_METRICS_SPARSE_HISTOGRAM_H_
   7
   8 #include <map>
   9 #include <string>
  10
  11 #include "base/base_export.h"
  12 #include "base/basictypes.h"
  13 #include "base/compiler_specific.h"
  14 #include "base/logging.h"
  15 #include "base/memory/scoped_ptr.h"
  16 #include "base/metrics/histogram_base.h"
  17 #include "base/metrics/sample_map.h"
  18 #include "base/synchronization/lock.h"
  19
  20 namespace base {
  21
  22 #define UMA_HISTOGRAM_SPARSE_SLOWLY(name, sample) \
  23     do { \
  24       base::HistogramBase* histogram = base::SparseHistogram::FactoryGet( \
  25           name, base::HistogramBase::kUmaTargetedHistogramFlag); \
  26       histogram->Add(sample); \
  27     } while (0)
  28
  29 class HistogramSamples;
  30
  31 class BASE_EXPORT_PRIVATE SparseHistogram : public HistogramBase {
  32  public:
  33   // If there's one with same name, return the existing one. If not, create a
  34   // new one.
  35   static HistogramBase* FactoryGet(const std::string& name, int32 flags);
  36
  37   ~SparseHistogram() override;
  38
  39   // HistogramBase implementation:
  40   HistogramType GetHistogramType() const override;
  41   bool HasConstructionArguments(Sample expected_minimum,
  42                                 Sample expected_maximum,
  43                                 size_t expected_bucket_count) const override;
  44   void Add(Sample value) override;
  45   void AddSamples(const HistogramSamples& samples) override;
  46   bool AddSamplesFromPickle(PickleIterator* iter) override;
  47   scoped_ptr<HistogramSamples> SnapshotSamples() const override;
  48   void WriteHTMLGraph(std::string* output) const override;
  49   void WriteAscii(std::string* output) const override;
  50
  51  protected:
  52   // HistogramBase implementation:
  53   bool SerializeInfoImpl(Pickle* pickle) const override;
  54
  55  private:
  56   // Clients should always use FactoryGet to create SparseHistogram.
  57   explicit SparseHistogram(const std::string& name);
  58
  59   friend BASE_EXPORT_PRIVATE HistogramBase* DeserializeHistogramInfo(
  60       PickleIterator* iter);
  61   static HistogramBase* DeserializeInfoImpl(PickleIterator* iter);
  62
  63   void GetParameters(DictionaryValue* params) const override;
  64   void GetCountAndBucketData(Count* count,
  65                              int64* sum,
  66                              ListValue* buckets) const override;
  67
  68   // Helpers for emitting Ascii graphic.  Each method appends data to output.
  69   void WriteAsciiImpl(bool graph_it,
  70                       const std::string& newline,
  71                       std::string* output) const;
  72
  73   // Write a common header message describing this histogram.
  74   void WriteAsciiHeader(const Count total_count,
  75                         std::string* output) const;
  76
  77   // For constuctor calling.
  78   friend class SparseHistogramTest;
  79
  80   // Protects access to |samples_|.
  81   mutable base::Lock lock_;
  82
  83   SampleMap samples_;
  84
  85   DISALLOW_COPY_AND_ASSIGN(SparseHistogram);
  86 };
  87
  88 }  // namespace base
  89
  90 #endif  // BASE_METRICS_SPARSE_HISTOGRAM_H_