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_HISTOGRAM_FLATTENER_H_
6 #define BASE_METRICS_HISTOGRAM_FLATTENER_H_
7 
8 #include <map>
9 #include <string>
10 
11 #include "base/macros.h"
12 #include "base/metrics/histogram.h"
13 
14 namespace base {
15 
16 class HistogramSamples;
17 
18 // HistogramFlattener is an interface used by HistogramSnapshotManager, which
19 // handles the logistics of gathering up available histograms for recording.
20 // The implementors handle the exact lower level recording mechanism, or
21 // error report mechanism.
22 class BASE_EXPORT HistogramFlattener {
23  public:
24   virtual void RecordDelta(const HistogramBase& histogram,
25                            const HistogramSamples& snapshot) = 0;
26 
27   // Will be called each time a type of Inconsistency is seen on a histogram,
28   // during inspections done internally in HistogramSnapshotManager class.
29   virtual void InconsistencyDetected(HistogramBase::Inconsistency problem) = 0;
30 
31   // Will be called when a type of Inconsistency is seen for the first time on
32   // a histogram.
33   virtual void UniqueInconsistencyDetected(
34       HistogramBase::Inconsistency problem) = 0;
35 
36   // Will be called when the total logged sample count of a histogram
37   // differs from the sum of logged sample count in all the buckets.  The
38   // argument |amount| is the non-zero discrepancy.
39   virtual void InconsistencyDetectedInLoggedCount(int amount) = 0;
40 
41  protected:
HistogramFlattener()42   HistogramFlattener() {}
~HistogramFlattener()43   virtual ~HistogramFlattener() {}
44 
45  private:
46   DISALLOW_COPY_AND_ASSIGN(HistogramFlattener);
47 };
48 
49 }  // namespace base
50 
51 #endif  // BASE_METRICS_HISTOGRAM_FLATTENER_H_
52