1 // Copyright 2017 The Chromium Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "base/metrics/dummy_histogram.h"
6
7 #include <memory>
8
9 #include "base/metrics/histogram_samples.h"
10 #include "base/metrics/metrics_hashes.h"
11 #include "base/no_destructor.h"
12 #include "base/notreached.h"
13 #include "base/values.h"
14
15 namespace base {
16
17 namespace {
18
19 // Helper classes for DummyHistogram.
20 class DummySampleCountIterator : public SampleCountIterator {
21 public:
22 DummySampleCountIterator() = default;
23 DummySampleCountIterator(const DummySampleCountIterator&) = delete;
24 DummySampleCountIterator& operator=(const DummySampleCountIterator&) = delete;
25 ~DummySampleCountIterator() override = default;
26
27 // SampleCountIterator:
Done() const28 bool Done() const override { return true; }
Next()29 void Next() override { NOTREACHED(); }
Get(HistogramBase::Sample * min,int64_t * max,HistogramBase::Count * count)30 void Get(HistogramBase::Sample* min,
31 int64_t* max,
32 HistogramBase::Count* count) override {
33 NOTREACHED();
34 }
35 };
36
37 class DummyHistogramSamples : public HistogramSamples {
38 public:
DummyHistogramSamples()39 DummyHistogramSamples()
40 : HistogramSamples(0, std::make_unique<LocalMetadata>()) {}
41 DummyHistogramSamples(const DummyHistogramSamples&) = delete;
42 DummyHistogramSamples& operator=(const DummyHistogramSamples&) = delete;
43
44 // HistogramSamples:
Accumulate(HistogramBase::Sample value,HistogramBase::Count count)45 void Accumulate(HistogramBase::Sample value,
46 HistogramBase::Count count) override {}
GetCount(HistogramBase::Sample value) const47 HistogramBase::Count GetCount(HistogramBase::Sample value) const override {
48 return HistogramBase::Count();
49 }
TotalCount() const50 HistogramBase::Count TotalCount() const override {
51 return HistogramBase::Count();
52 }
Iterator() const53 std::unique_ptr<SampleCountIterator> Iterator() const override {
54 return std::make_unique<DummySampleCountIterator>();
55 }
ExtractingIterator()56 std::unique_ptr<SampleCountIterator> ExtractingIterator() override {
57 return std::make_unique<DummySampleCountIterator>();
58 }
IsDefinitelyEmpty() const59 bool IsDefinitelyEmpty() const override {
60 NOTREACHED();
61 return true;
62 }
AddSubtractImpl(SampleCountIterator * iter,Operator op)63 bool AddSubtractImpl(SampleCountIterator* iter, Operator op) override {
64 return true;
65 }
66 };
67
68 } // namespace
69
70 // static
GetInstance()71 DummyHistogram* DummyHistogram::GetInstance() {
72 static base::NoDestructor<DummyHistogram> dummy_histogram;
73 return dummy_histogram.get();
74 }
75
name_hash() const76 uint64_t DummyHistogram::name_hash() const {
77 return HashMetricName(histogram_name());
78 }
79
GetHistogramType() const80 HistogramType DummyHistogram::GetHistogramType() const {
81 return DUMMY_HISTOGRAM;
82 }
83
HasConstructionArguments(Sample expected_minimum,Sample expected_maximum,size_t expected_bucket_count) const84 bool DummyHistogram::HasConstructionArguments(
85 Sample expected_minimum,
86 Sample expected_maximum,
87 size_t expected_bucket_count) const {
88 return true;
89 }
90
AddSamplesFromPickle(PickleIterator * iter)91 bool DummyHistogram::AddSamplesFromPickle(PickleIterator* iter) {
92 return true;
93 }
94
SnapshotSamples() const95 std::unique_ptr<HistogramSamples> DummyHistogram::SnapshotSamples() const {
96 return std::make_unique<DummyHistogramSamples>();
97 }
98
SnapshotUnloggedSamples() const99 std::unique_ptr<HistogramSamples> DummyHistogram::SnapshotUnloggedSamples()
100 const {
101 return std::make_unique<DummyHistogramSamples>();
102 }
103
SnapshotDelta()104 std::unique_ptr<HistogramSamples> DummyHistogram::SnapshotDelta() {
105 return std::make_unique<DummyHistogramSamples>();
106 }
107
SnapshotFinalDelta() const108 std::unique_ptr<HistogramSamples> DummyHistogram::SnapshotFinalDelta() const {
109 return std::make_unique<DummyHistogramSamples>();
110 }
111
ToGraphDict() const112 Value::Dict DummyHistogram::ToGraphDict() const {
113 return Value::Dict();
114 }
115
GetParameters() const116 Value::Dict DummyHistogram::GetParameters() const {
117 return Value::Dict();
118 }
119
120 } // namespace base
121