| // Copyright 2014 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "base/test/statistics_delta_reader.h" |
| |
| #include "base/metrics/histogram.h" |
| #include "base/metrics/histogram_samples.h" |
| #include "base/metrics/statistics_recorder.h" |
| #include "base/stl_util.h" |
| |
| namespace base { |
| |
| StatisticsDeltaReader::StatisticsDeltaReader() { |
| StatisticsRecorder::Initialize(); // Safe to call multiple times. |
| |
| // Record any histogram data that exists when the object is created so it can |
| // be subtracted later. |
| StatisticsRecorder::Histograms histograms; |
| StatisticsRecorder::GetSnapshot(std::string(), &histograms); |
| for (size_t i = 0; i < histograms.size(); ++i) { |
| original_samples_[histograms[i]->histogram_name()] = |
| histograms[i]->SnapshotSamples().release(); |
| } |
| } |
| |
| StatisticsDeltaReader::~StatisticsDeltaReader() { |
| STLDeleteValues(&original_samples_); |
| } |
| |
| scoped_ptr<HistogramSamples> |
| StatisticsDeltaReader::GetHistogramSamplesSinceCreation( |
| const std::string& histogram_name) { |
| HistogramBase* histogram = StatisticsRecorder::FindHistogram(histogram_name); |
| if (!histogram) |
| return scoped_ptr<HistogramSamples>(); |
| scoped_ptr<HistogramSamples> named_samples(histogram->SnapshotSamples()); |
| HistogramSamples* named_original_samples = original_samples_[histogram_name]; |
| if (named_original_samples) |
| named_samples->Subtract(*named_original_samples); |
| return named_samples.Pass(); |
| } |
| |
| } // namespace base |