Index: base/metrics/persistent_sample_map.h |
diff --git a/base/metrics/persistent_sample_map.h b/base/metrics/persistent_sample_map.h |
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+// Copyright 2016 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. |
+ |
+// PersistentSampleMap implements HistogramSamples interface. It is used |
+// by the SparseHistogram class to store samples in persistent memory which |
+// allows it to be shared between processes or live across restarts. |
+ |
+#ifndef BASE_METRICS_PERSISTENT_SAMPLE_MAP_H_ |
+#define BASE_METRICS_PERSISTENT_SAMPLE_MAP_H_ |
+ |
+#include <stdint.h> |
+ |
+#include <map> |
+ |
+#include "base/compiler_specific.h" |
+#include "base/macros.h" |
+#include "base/memory/scoped_ptr.h" |
+#include "base/metrics/histogram_base.h" |
+#include "base/metrics/histogram_samples.h" |
+#include "base/metrics/persistent_memory_allocator.h" |
+ |
+namespace base { |
+ |
+// The logic here is similar to that of SampleMap but with different data |
+// structures. Changes here likely need to be duplicated there. |
+class BASE_EXPORT PersistentSampleMap : public HistogramSamples { |
+ public: |
+ PersistentSampleMap(uint64_t id, |
+ PersistentMemoryAllocator* allocator, |
+ Metadata* meta); |
+ ~PersistentSampleMap() override; |
+ |
+ // HistogramSamples: |
+ void Accumulate(HistogramBase::Sample value, |
+ HistogramBase::Count count) override; |
+ HistogramBase::Count GetCount(HistogramBase::Sample value) const override; |
+ HistogramBase::Count TotalCount() const override; |
+ scoped_ptr<SampleCountIterator> Iterator() const override; |
+ |
+ protected: |
+ // Performs arithemetic. |op| is ADD or SUBTRACT. |
+ bool AddSubtractImpl(SampleCountIterator* iter, Operator op) override; |
+ |
+ // Gets a pointer to a "count" corresponding to a given |value|. Returns NULL |
+ // if sample does not exist. |
+ HistogramBase::Count* GetSampleCountStorage(HistogramBase::Sample value); |
+ |
+ // Gets a pointer to a "count" corresponding to a given |value|, creating |
+ // the sample (initialized to zero) if it does not already exists. |
+ HistogramBase::Count* GetOrCreateSampleCountStorage( |
+ HistogramBase::Sample value); |
+ |
+ private: |
+ enum : HistogramBase::Sample { kAllSamples = -1 }; |
+ |
+ // Imports samples from persistent memory by iterating over all sample |
+ // records found therein, adding them to the sample_counts_ map. If a |
+ // count for the sample |until_value| is found, stop the import and return |
+ // a pointer to that counter. If that value is not found, null will be |
+ // returned after all currently available samples have been loaded. Pass |
+ // kAllSamples to force the importing of all available samples. |
+ HistogramBase::Count* ImportSamples(HistogramBase::Sample until_value); |
+ |
+ // All created/loaded sample values and their associated counts. The storage |
+ // for the actual Count numbers is owned by the |allocator_|. |
+ std::map<HistogramBase::Sample, HistogramBase::Count*> sample_counts_; |
+ |
+ // The persistent memory allocator holding samples and an iterator through it. |
+ PersistentMemoryAllocator* allocator_; |
+ PersistentMemoryAllocator::Iterator sample_iter_; |
+ |
+ DISALLOW_COPY_AND_ASSIGN(PersistentSampleMap); |
+}; |
+ |
+} // namespace base |
+ |
+#endif // BASE_METRICS_PERSISTENT_SAMPLE_MAP_H_ |