Add support for persistent sparse histograms.

base/metrics/sample_map.cc

 // Copyright (c) 2012 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/metrics/sample_map.h"
 
 #include "base/logging.h"
+#include "base/stl_util.h"
 
 namespace base {
 
 typedef HistogramBase::Count Count;
 typedef HistogramBase::Sample Sample;
 
 SampleMap::SampleMap() : SampleMap(0) {}
 
 SampleMap::SampleMap(uint64_t id) : HistogramSamples(id) {}
 
 SampleMap::~SampleMap() {}
 
 void SampleMap::Accumulate(Sample value, Count count) {
   sample_counts_[value] += count;
   IncreaseSum(static_cast<int64_t>(count) * value);
   IncreaseRedundantCount(count);
 }
 
 Count SampleMap::GetCount(Sample value) const {
   std::map<Sample, Count>::const_iterator it = sample_counts_.find(value);
   if (it == sample_counts_.end())
     return 0;
   return it->second;
 }
 
 Count SampleMap::TotalCount() const {
   Count count = 0;
-  for (const auto& entry : sample_counts_) {
+  for (const auto& entry : sample_counts_)
     count += entry.second;
-  }
   return count;
 }
 
 scoped_ptr<SampleCountIterator> SampleMap::Iterator() const {
-  return scoped_ptr<SampleCountIterator>(new SampleMapIterator(sample_counts_));
+  return make_scoped_ptr(new SampleMapIterator(sample_counts_));
 }
 
-bool SampleMap::AddSubtractImpl(SampleCountIterator* iter,
-                                HistogramSamples::Operator op) {
+bool SampleMap::AddSubtractImpl(SampleCountIterator* iter, Operator op) {
   Sample min;
   Sample max;
   Count count;
   for (; !iter->Done(); iter->Next()) {
     iter->Get(&min, &max, &count);
     if (min + 1 != max)
       return false;  // SparseHistogram only supports bucket with size 1.
 
     sample_counts_[min] += (op == HistogramSamples::ADD) ? count : -count;
   }
@@ skipping 13 matching lines @@
 }
 
 void SampleMapIterator::Next() {
   DCHECK(!Done());
   ++iter_;
   SkipEmptyBuckets();
 }
 
 void SampleMapIterator::Get(Sample* min, Sample* max, Count* count) const {
   DCHECK(!Done());
-  if (min != NULL)
+  if (min)
     *min = iter_->first;
-  if (max != NULL)
+  if (max)
     *max = iter_->first + 1;
-  if (count != NULL)
+  if (count)
     *count = iter_->second;
 }
 
 void SampleMapIterator::SkipEmptyBuckets() {
-  while (!Done() && iter_->second == 0) {
+  while (!Done() && iter_->second == 0)
     ++iter_;
-  }
 }
 
 }  // namespace base