1 // Copyright 2014 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/test/statistics_delta_reader.h" 6 7 #include "base/metrics/histogram.h" 8 #include "base/metrics/histogram_samples.h" 9 #include "base/metrics/statistics_recorder.h" 10 #include "base/stl_util.h" 11 12 namespace base { 13 14 StatisticsDeltaReader::StatisticsDeltaReader() { 15 StatisticsRecorder::Initialize(); // Safe to call multiple times. 16 17 // Record any histogram data that exists when the object is created so it can 18 // be subtracted later. 19 StatisticsRecorder::Histograms histograms; 20 StatisticsRecorder::GetSnapshot(std::string(), &histograms); 21 for (size_t i = 0; i < histograms.size(); ++i) { 22 original_samples_[histograms[i]->histogram_name()] = 23 histograms[i]->SnapshotSamples().release(); 24 } 25 } 26 27 StatisticsDeltaReader::~StatisticsDeltaReader() { 28 STLDeleteValues(&original_samples_); 29 } 30 31 scoped_ptr<HistogramSamples> 32 StatisticsDeltaReader::GetHistogramSamplesSinceCreation( 33 const std::string& histogram_name) { 34 HistogramBase* histogram = StatisticsRecorder::FindHistogram(histogram_name); 35 if (!histogram) 36 return scoped_ptr<HistogramSamples>(); 37 scoped_ptr<HistogramSamples> named_samples(histogram->SnapshotSamples()); 38 HistogramSamples* named_original_samples = original_samples_[histogram_name]; 39 if (named_original_samples) 40 named_samples->Subtract(*named_original_samples); 41 return named_samples.Pass(); 42 } 43 44 } // namespace base 45
