chrome_frame/chrome_frame_histograms.cc

   1 // Copyright (c) 2009 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 "chrome_frame/chrome_frame_histograms.h"
   6
   7 #include "base/histogram.h"
   8 #include "base/lazy_instance.h"
   9 #include "base/logging.h"
  10 #include "base/message_loop.h"
  11 #include "base/pickle.h"
  12
  13   // Initialize histogram statistics gathering system.
  14 base::LazyInstance<StatisticsRecorder>
  15     g_statistics_recorder_(base::LINKER_INITIALIZED);
  16
  17 ChromeFrameHistogramSnapshots::ChromeFrameHistogramSnapshots() {
  18   // Ensure that an instance of the StatisticsRecorder object is created.
  19   g_statistics_recorder_.Get();
  20 }
  21
  22 ChromeFrameHistogramSnapshots::HistogramPickledList
  23   ChromeFrameHistogramSnapshots::GatherAllHistograms() {
  24
  25   AutoLock auto_lock(lock_);
  26
  27   StatisticsRecorder::Histograms histograms;
  28   StatisticsRecorder::GetHistograms(&histograms);
  29
  30   HistogramPickledList pickled_histograms;
  31
  32   for (StatisticsRecorder::Histograms::iterator it = histograms.begin();
  33        histograms.end() != it;
  34        it++) {
  35     (*it)->SetFlags(Histogram::kIPCSerializationSourceFlag);
  36     GatherHistogram(**it, &pickled_histograms);
  37   }
  38
  39   return pickled_histograms;
  40 }
  41
  42 void ChromeFrameHistogramSnapshots::GatherHistogram(
  43     const Histogram& histogram,
  44     HistogramPickledList* pickled_histograms) {
  45
  46   // Get up-to-date snapshot of sample stats.
  47   Histogram::SampleSet snapshot;
  48   histogram.SnapshotSample(&snapshot);
  49   const std::string& histogram_name = histogram.histogram_name();
  50
  51   // Check if we already have a log of this histogram and if not create an
  52   // empty set.
  53   LoggedSampleMap::iterator it = logged_samples_.find(histogram_name);
  54   Histogram::SampleSet* already_logged;
  55   if (logged_samples_.end() == it) {
  56     // Add new entry.
  57     already_logged = &logged_samples_[histogram.histogram_name()];
  58     already_logged->Resize(histogram);  // Complete initialization.
  59   } else {
  60     already_logged = &(it->second);
  61     // Deduct any stats we've already logged from our snapshot.
  62     snapshot.Subtract(*already_logged);
  63   }
  64
  65   // Snapshot now contains only a delta to what we've already_logged.
  66   if (snapshot.TotalCount() > 0) {
  67     GatherHistogramDelta(histogram, snapshot, pickled_histograms);
  68     // Add new data into our running total.
  69     already_logged->Add(snapshot);
  70   }
  71 }
  72
  73 void ChromeFrameHistogramSnapshots::GatherHistogramDelta(
  74     const Histogram& histogram,
  75     const Histogram::SampleSet& snapshot,
  76     HistogramPickledList* pickled_histograms) {
  77
  78   DCHECK(0 != snapshot.TotalCount());
  79   snapshot.CheckSize(histogram);
  80
  81   std::string histogram_info =
  82       Histogram::SerializeHistogramInfo(histogram, snapshot);
  83   pickled_histograms->push_back(histogram_info);
  84 }