1// Copyright (c) 2011 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 NET_DISK_CACHE_STATS_HISTOGRAM_H_
6#define NET_DISK_CACHE_STATS_HISTOGRAM_H_
7#pragma once
8
9#include <string>
10
11#include "base/metrics/histogram.h"
12
13namespace disk_cache {
14
15class Stats;
16
17// This class provides support for sending the disk cache size stats as a UMA
18// histogram. We'll provide our own storage and management for the data, and a
19// SampleSet with a copy of our data.
20//
21// Class derivation of Histogram "deprecated," and should not be copied, and
22// may eventually go away.
23//
24class StatsHistogram : public base::Histogram {
25 public:
26  class StatsSamples : public SampleSet {
27   public:
28    Counts* GetCounts() {
29      return &counts_;
30    }
31  };
32
33  explicit StatsHistogram(const std::string& name, Sample minimum,
34                          Sample maximum, size_t bucket_count)
35      : Histogram(name, minimum, maximum, bucket_count), init_(false) {}
36  ~StatsHistogram();
37
38  static StatsHistogram* StatsHistogramFactoryGet(const std::string& name);
39
40  // We'll be reporting data from the given set of cache stats.
41  bool Init(const Stats* stats);
42
43  virtual Sample ranges(size_t i) const;
44  virtual size_t bucket_count() const;
45  virtual void SnapshotSample(SampleSet* sample) const;
46  virtual Inconsistencies FindCorruption(const SampleSet& snapshot) const;
47  virtual uint32 CalculateRangeChecksum() const;
48
49 private:
50  bool init_;
51  static const Stats* stats_;
52  DISALLOW_COPY_AND_ASSIGN(StatsHistogram);
53};
54
55}  // namespace disk_cache
56
57#endif  // NET_DISK_CACHE_STATS_HISTOGRAM_H_
58