Home | History | Annotate | Download | only in metrics 
      1 // Copyright 2017 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 #include "base/metrics/dummy_histogram.h"
      6 
      7 #include <memory>
      8 
      9 #include "base/logging.h"
     10 #include "base/metrics/histogram_samples.h"
     11 #include "base/metrics/metrics_hashes.h"
     12 
     13 namespace base {
     14 
     15 namespace {
     16 
     17 // Helper classes for DummyHistogram.
     18 class DummySampleCountIterator : public SampleCountIterator {
     19  public:
     20   DummySampleCountIterator() {}
     21   ~DummySampleCountIterator() override {}
     22 
     23   // SampleCountIterator:
     24   bool Done() const override { return true; }
     25   void Next() override { NOTREACHED(); }
     26   void Get(HistogramBase::Sample* min,
     27            int64_t* max,
     28            HistogramBase::Count* count) const override {
     29     NOTREACHED();
     30   }
     31 
     32  private:
     33   DISALLOW_COPY_AND_ASSIGN(DummySampleCountIterator);
     34 };
     35 
     36 class DummyHistogramSamples : public HistogramSamples {
     37  public:
     38   explicit DummyHistogramSamples() : HistogramSamples(0, new LocalMetadata()) {}
     39   ~DummyHistogramSamples() override {
     40     delete static_cast<LocalMetadata*>(meta());
     41   }
     42 
     43   // HistogramSamples:
     44   void Accumulate(HistogramBase::Sample value,
     45                   HistogramBase::Count count) override {}
     46   HistogramBase::Count GetCount(HistogramBase::Sample value) const override {
     47     return HistogramBase::Count();
     48   }
     49   HistogramBase::Count TotalCount() const override {
     50     return HistogramBase::Count();
     51   }
     52   std::unique_ptr<SampleCountIterator> Iterator() const override {
     53     return std::make_unique<DummySampleCountIterator>();
     54   }
     55   bool AddSubtractImpl(SampleCountIterator* iter, Operator op) override {
     56     return true;
     57   }
     58 
     59  private:
     60   DISALLOW_COPY_AND_ASSIGN(DummyHistogramSamples);
     61 };
     62 
     63 }  // namespace
     64 
     65 // static
     66 DummyHistogram* DummyHistogram::GetInstance() {
     67   static base::NoDestructor<DummyHistogram> dummy_histogram;
     68   return dummy_histogram.get();
     69 }
     70 
     71 uint64_t DummyHistogram::name_hash() const {
     72   return HashMetricName(histogram_name());
     73 }
     74 
     75 HistogramType DummyHistogram::GetHistogramType() const {
     76   return DUMMY_HISTOGRAM;
     77 }
     78 
     79 bool DummyHistogram::HasConstructionArguments(
     80     Sample expected_minimum,
     81     Sample expected_maximum,
     82     uint32_t expected_bucket_count) const {
     83   return true;
     84 }
     85 
     86 bool DummyHistogram::AddSamplesFromPickle(PickleIterator* iter) {
     87   return true;
     88 }
     89 
     90 std::unique_ptr<HistogramSamples> DummyHistogram::SnapshotSamples() const {
     91   return std::make_unique<DummyHistogramSamples>();
     92 }
     93 
     94 std::unique_ptr<HistogramSamples> DummyHistogram::SnapshotDelta() {
     95   return std::make_unique<DummyHistogramSamples>();
     96 }
     97 
     98 std::unique_ptr<HistogramSamples> DummyHistogram::SnapshotFinalDelta() const {
     99   return std::make_unique<DummyHistogramSamples>();
    100 }
    101 
    102 }  // namespace base
    103