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 // The common code for different SparseHistogram macros.
  23 #define HISTOGRAM_SPARSE_COMMON(name, sample, flag) \
  24     do { \
  25       base::HistogramBase* histogram( \
  26           base::SparseHistogram::FactoryGet(name, flag)); \
  27       DCHECK_EQ(histogram->histogram_name(), name); \
  28       histogram->Add(sample); \
  29     } while (0)
  30
  31 #define HISTOGRAM_SPARSE_SLOWLY(name, sample) \
  32     HISTOGRAM_SPARSE_COMMON(name, sample, base::HistogramBase::kNoFlags)
  33
  34 #define UMA_HISTOGRAM_SPARSE_SLOWLY(name, sample) \
  35     HISTOGRAM_SPARSE_COMMON(name, sample, \
  36                             base::HistogramBase::kUmaTargetedHistogramFlag)
  37
  38 //------------------------------------------------------------------------------
  39 // Define debug only version of macros.
  40 #ifndef NDEBUG
  41
  42 #define DHISTOGRAM_SPARSE_SLOWLY(name, sample) \
  43     HISTOGRAM_SPARSE_SLOWLY(name, sample)
  44
  45 #else  // NDEBUG
  46
  47 #define DHISTOGRAM_SPARSE_SLOWLY(name, sample) \
  48     while (0) { \
  49       static_cast<void>(name); \
  50       static_cast<void>(sample); \
  51     }
  52
  53 #endif  // NDEBUG
  54
  55 class HistogramSamples;
  56
  57 class BASE_EXPORT_PRIVATE SparseHistogram : public HistogramBase {
  58  public:
  59   // If there's one with same name, return the existing one. If not, create a
  60   // new one.
  61   static HistogramBase* FactoryGet(const std::string& name, int32 flags);
  62
  63   virtual ~SparseHistogram();
  64
  65   // HistogramBase implementation:
  66   virtual HistogramType GetHistogramType() const OVERRIDE;
  67   virtual bool HasConstructionArguments(
  68       Sample expected_minimum,
  69       Sample expected_maximum,
  70       size_t expected_bucket_count) const OVERRIDE;
  71   virtual void Add(Sample value) OVERRIDE;
  72   virtual void AddSamples(const HistogramSamples& samples) OVERRIDE;
  73   virtual bool AddSamplesFromPickle(PickleIterator* iter) OVERRIDE;
  74   virtual scoped_ptr<HistogramSamples> SnapshotSamples() const OVERRIDE;
  75   virtual void WriteHTMLGraph(std::string* output) const OVERRIDE;
  76   virtual void WriteAscii(std::string* output) const OVERRIDE;
  77
  78  protected:
  79   // HistogramBase implementation:
  80   virtual bool SerializeInfoImpl(Pickle* pickle) const OVERRIDE;
  81
  82  private:
  83   // Clients should always use FactoryGet to create SparseHistogram.
  84   explicit SparseHistogram(const std::string& name);
  85
  86   friend BASE_EXPORT_PRIVATE HistogramBase* DeserializeHistogramInfo(
  87       PickleIterator* iter);
  88   static HistogramBase* DeserializeInfoImpl(PickleIterator* iter);
  89
  90   virtual void GetParameters(DictionaryValue* params) const OVERRIDE;
  91   virtual void GetCountAndBucketData(Count* count,
  92                                      int64* sum,
  93                                      ListValue* buckets) const OVERRIDE;
  94
  95   // Helpers for emitting Ascii graphic.  Each method appends data to output.
  96   void WriteAsciiImpl(bool graph_it,
  97                       const std::string& newline,
  98                       std::string* output) const;
  99
 100   // Write a common header message describing this histogram.
 101   void WriteAsciiHeader(const Count total_count,
 102                         std::string* output) const;
 103
 104   // For constuctor calling.
 105   friend class SparseHistogramTest;
 106
 107   // Protects access to |samples_|.
 108   mutable base::Lock lock_;
 109
 110   SampleMap samples_;
 111
 112   DISALLOW_COPY_AND_ASSIGN(SparseHistogram);
 113 };
 114
 115 }  // namespace base
 116
 117 #endif  // BASE_METRICS_SPARSE_HISTOGRAM_H_